]> git.ipfire.org Git - thirdparty/vim.git/commitdiff
Git 2.40
authorJunio C Hamano <gitster@pobox.com>
Sun, 12 Mar 2023 21:34:41 +0000 (14:34 -0700)
committerdummy <dummy>
Sun, 13 Sep 2020 12:26:40 +0000 (12:26 +0000)
Signed-off-by: Junio C Hamano <gitster@pobox.com>
14 files changed:
xdiff.h [new file with mode: 0644]
xdiffi.c [new file with mode: 0644]
xdiffi.h [new file with mode: 0644]
xemit.c [new file with mode: 0644]
xemit.h [new file with mode: 0644]
xhistogram.c [new file with mode: 0644]
xinclude.h [new file with mode: 0644]
xmacros.h [new file with mode: 0644]
xpatience.c [new file with mode: 0644]
xprepare.c [new file with mode: 0644]
xprepare.h [new file with mode: 0644]
xtypes.h [new file with mode: 0644]
xutils.c [new file with mode: 0644]
xutils.h [new file with mode: 0644]

diff --git a/xdiff.h b/xdiff.h
new file mode 100644 (file)
index 0000000..bb56b23
--- /dev/null
+++ b/xdiff.h
@@ -0,0 +1,153 @@
+/*
+ *  LibXDiff by Davide Libenzi ( File Differential Library )
+ *  Copyright (C) 2003  Davide Libenzi
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Lesser General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 2.1 of the License, or (at your option) any later version.
+ *
+ *  This library is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public
+ *  License along with this library; if not, see
+ *  <http://www.gnu.org/licenses/>.
+ *
+ *  Davide Libenzi <davidel@xmailserver.org>
+ *
+ */
+
+#if !defined(XDIFF_H)
+#define XDIFF_H
+
+#ifdef __cplusplus
+extern "C" {
+#endif /* #ifdef __cplusplus */
+
+/* xpparm_t.flags */
+#define XDF_NEED_MINIMAL (1 << 0)
+
+#define XDF_IGNORE_WHITESPACE (1 << 1)
+#define XDF_IGNORE_WHITESPACE_CHANGE (1 << 2)
+#define XDF_IGNORE_WHITESPACE_AT_EOL (1 << 3)
+#define XDF_IGNORE_CR_AT_EOL (1 << 4)
+#define XDF_WHITESPACE_FLAGS (XDF_IGNORE_WHITESPACE | \
+                             XDF_IGNORE_WHITESPACE_CHANGE | \
+                             XDF_IGNORE_WHITESPACE_AT_EOL | \
+                             XDF_IGNORE_CR_AT_EOL)
+
+#define XDF_IGNORE_BLANK_LINES (1 << 7)
+
+#define XDF_PATIENCE_DIFF (1 << 14)
+#define XDF_HISTOGRAM_DIFF (1 << 15)
+#define XDF_DIFF_ALGORITHM_MASK (XDF_PATIENCE_DIFF | XDF_HISTOGRAM_DIFF)
+#define XDF_DIFF_ALG(x) ((x) & XDF_DIFF_ALGORITHM_MASK)
+
+#define XDF_INDENT_HEURISTIC (1 << 23)
+
+/* xdemitconf_t.flags */
+#define XDL_EMIT_FUNCNAMES (1 << 0)
+#define XDL_EMIT_NO_HUNK_HDR (1 << 1)
+#define XDL_EMIT_FUNCCONTEXT (1 << 2)
+
+/* merge simplification levels */
+#define XDL_MERGE_MINIMAL 0
+#define XDL_MERGE_EAGER 1
+#define XDL_MERGE_ZEALOUS 2
+#define XDL_MERGE_ZEALOUS_ALNUM 3
+
+/* merge favor modes */
+#define XDL_MERGE_FAVOR_OURS 1
+#define XDL_MERGE_FAVOR_THEIRS 2
+#define XDL_MERGE_FAVOR_UNION 3
+
+/* merge output styles */
+#define XDL_MERGE_DIFF3 1
+#define XDL_MERGE_ZEALOUS_DIFF3 2
+
+typedef struct s_mmfile {
+       char *ptr;
+       long size;
+} mmfile_t;
+
+typedef struct s_mmbuffer {
+       char *ptr;
+       long size;
+} mmbuffer_t;
+
+typedef struct s_xpparam {
+       unsigned long flags;
+
+       /* -I<regex> */
+       regex_t **ignore_regex;
+       size_t ignore_regex_nr;
+
+       /* See Documentation/diff-options.txt. */
+       char **anchors;
+       size_t anchors_nr;
+} xpparam_t;
+
+typedef struct s_xdemitcb {
+       void *priv;
+       int (*out_hunk)(void *,
+                       long old_begin, long old_nr,
+                       long new_begin, long new_nr,
+                       const char *func, long funclen);
+       int (*out_line)(void *, mmbuffer_t *, int);
+} xdemitcb_t;
+
+typedef long (*find_func_t)(const char *line, long line_len, char *buffer, long buffer_size, void *priv);
+
+typedef int (*xdl_emit_hunk_consume_func_t)(long start_a, long count_a,
+                                           long start_b, long count_b,
+                                           void *cb_data);
+
+typedef struct s_xdemitconf {
+       long ctxlen;
+       long interhunkctxlen;
+       unsigned long flags;
+       find_func_t find_func;
+       void *find_func_priv;
+       xdl_emit_hunk_consume_func_t hunk_func;
+} xdemitconf_t;
+
+typedef struct s_bdiffparam {
+       long bsize;
+} bdiffparam_t;
+
+
+#define xdl_malloc(x) xmalloc(x)
+#define xdl_calloc(n, sz) xcalloc(n, sz)
+#define xdl_free(ptr) free(ptr)
+#define xdl_realloc(ptr,x) xrealloc(ptr,x)
+
+void *xdl_mmfile_first(mmfile_t *mmf, long *size);
+long xdl_mmfile_size(mmfile_t *mmf);
+
+int xdl_diff(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp,
+            xdemitconf_t const *xecfg, xdemitcb_t *ecb);
+
+typedef struct s_xmparam {
+       xpparam_t xpp;
+       int marker_size;
+       int level;
+       int favor;
+       int style;
+       const char *ancestor;   /* label for orig */
+       const char *file1;      /* label for mf1 */
+       const char *file2;      /* label for mf2 */
+} xmparam_t;
+
+#define DEFAULT_CONFLICT_MARKER_SIZE 7
+
+int xdl_merge(mmfile_t *orig, mmfile_t *mf1, mmfile_t *mf2,
+               xmparam_t const *xmp, mmbuffer_t *result);
+
+#ifdef __cplusplus
+}
+#endif /* #ifdef __cplusplus */
+
+#endif /* #if !defined(XDIFF_H) */
diff --git a/xdiffi.c b/xdiffi.c
new file mode 100644 (file)
index 0000000..344c2df
--- /dev/null
+++ b/xdiffi.c
@@ -0,0 +1,1089 @@
+/*
+ *  LibXDiff by Davide Libenzi ( File Differential Library )
+ *  Copyright (C) 2003 Davide Libenzi
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Lesser General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 2.1 of the License, or (at your option) any later version.
+ *
+ *  This library is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public
+ *  License along with this library; if not, see
+ *  <http://www.gnu.org/licenses/>.
+ *
+ *  Davide Libenzi <davidel@xmailserver.org>
+ *
+ */
+
+#include "xinclude.h"
+
+#define XDL_MAX_COST_MIN 256
+#define XDL_HEUR_MIN_COST 256
+#define XDL_LINE_MAX (long)((1UL << (CHAR_BIT * sizeof(long) - 1)) - 1)
+#define XDL_SNAKE_CNT 20
+#define XDL_K_HEUR 4
+
+typedef struct s_xdpsplit {
+       long i1, i2;
+       int min_lo, min_hi;
+} xdpsplit_t;
+
+/*
+ * See "An O(ND) Difference Algorithm and its Variations", by Eugene Myers.
+ * Basically considers a "box" (off1, off2, lim1, lim2) and scan from both
+ * the forward diagonal starting from (off1, off2) and the backward diagonal
+ * starting from (lim1, lim2). If the K values on the same diagonal crosses
+ * returns the furthest point of reach. We might encounter expensive edge cases
+ * using this algorithm, so a little bit of heuristic is needed to cut the
+ * search and to return a suboptimal point.
+ */
+static long xdl_split(unsigned long const *ha1, long off1, long lim1,
+                     unsigned long const *ha2, long off2, long lim2,
+                     long *kvdf, long *kvdb, int need_min, xdpsplit_t *spl,
+                     xdalgoenv_t *xenv) {
+       long dmin = off1 - lim2, dmax = lim1 - off2;
+       long fmid = off1 - off2, bmid = lim1 - lim2;
+       long odd = (fmid - bmid) & 1;
+       long fmin = fmid, fmax = fmid;
+       long bmin = bmid, bmax = bmid;
+       long ec, d, i1, i2, prev1, best, dd, v, k;
+
+       /*
+        * Set initial diagonal values for both forward and backward path.
+        */
+       kvdf[fmid] = off1;
+       kvdb[bmid] = lim1;
+
+       for (ec = 1;; ec++) {
+               int got_snake = 0;
+
+               /*
+                * We need to extend the diagonal "domain" by one. If the next
+                * values exits the box boundaries we need to change it in the
+                * opposite direction because (max - min) must be a power of
+                * two.
+                *
+                * Also we initialize the external K value to -1 so that we can
+                * avoid extra conditions in the check inside the core loop.
+                */
+               if (fmin > dmin)
+                       kvdf[--fmin - 1] = -1;
+               else
+                       ++fmin;
+               if (fmax < dmax)
+                       kvdf[++fmax + 1] = -1;
+               else
+                       --fmax;
+
+               for (d = fmax; d >= fmin; d -= 2) {
+                       if (kvdf[d - 1] >= kvdf[d + 1])
+                               i1 = kvdf[d - 1] + 1;
+                       else
+                               i1 = kvdf[d + 1];
+                       prev1 = i1;
+                       i2 = i1 - d;
+                       for (; i1 < lim1 && i2 < lim2 && ha1[i1] == ha2[i2]; i1++, i2++);
+                       if (i1 - prev1 > xenv->snake_cnt)
+                               got_snake = 1;
+                       kvdf[d] = i1;
+                       if (odd && bmin <= d && d <= bmax && kvdb[d] <= i1) {
+                               spl->i1 = i1;
+                               spl->i2 = i2;
+                               spl->min_lo = spl->min_hi = 1;
+                               return ec;
+                       }
+               }
+
+               /*
+                * We need to extend the diagonal "domain" by one. If the next
+                * values exits the box boundaries we need to change it in the
+                * opposite direction because (max - min) must be a power of
+                * two.
+                *
+                * Also we initialize the external K value to -1 so that we can
+                * avoid extra conditions in the check inside the core loop.
+                */
+               if (bmin > dmin)
+                       kvdb[--bmin - 1] = XDL_LINE_MAX;
+               else
+                       ++bmin;
+               if (bmax < dmax)
+                       kvdb[++bmax + 1] = XDL_LINE_MAX;
+               else
+                       --bmax;
+
+               for (d = bmax; d >= bmin; d -= 2) {
+                       if (kvdb[d - 1] < kvdb[d + 1])
+                               i1 = kvdb[d - 1];
+                       else
+                               i1 = kvdb[d + 1] - 1;
+                       prev1 = i1;
+                       i2 = i1 - d;
+                       for (; i1 > off1 && i2 > off2 && ha1[i1 - 1] == ha2[i2 - 1]; i1--, i2--);
+                       if (prev1 - i1 > xenv->snake_cnt)
+                               got_snake = 1;
+                       kvdb[d] = i1;
+                       if (!odd && fmin <= d && d <= fmax && i1 <= kvdf[d]) {
+                               spl->i1 = i1;
+                               spl->i2 = i2;
+                               spl->min_lo = spl->min_hi = 1;
+                               return ec;
+                       }
+               }
+
+               if (need_min)
+                       continue;
+
+               /*
+                * If the edit cost is above the heuristic trigger and if
+                * we got a good snake, we sample current diagonals to see
+                * if some of them have reached an "interesting" path. Our
+                * measure is a function of the distance from the diagonal
+                * corner (i1 + i2) penalized with the distance from the
+                * mid diagonal itself. If this value is above the current
+                * edit cost times a magic factor (XDL_K_HEUR) we consider
+                * it interesting.
+                */
+               if (got_snake && ec > xenv->heur_min) {
+                       for (best = 0, d = fmax; d >= fmin; d -= 2) {
+                               dd = d > fmid ? d - fmid: fmid - d;
+                               i1 = kvdf[d];
+                               i2 = i1 - d;
+                               v = (i1 - off1) + (i2 - off2) - dd;
+
+                               if (v > XDL_K_HEUR * ec && v > best &&
+                                   off1 + xenv->snake_cnt <= i1 && i1 < lim1 &&
+                                   off2 + xenv->snake_cnt <= i2 && i2 < lim2) {
+                                       for (k = 1; ha1[i1 - k] == ha2[i2 - k]; k++)
+                                               if (k == xenv->snake_cnt) {
+                                                       best = v;
+                                                       spl->i1 = i1;
+                                                       spl->i2 = i2;
+                                                       break;
+                                               }
+                               }
+                       }
+                       if (best > 0) {
+                               spl->min_lo = 1;
+                               spl->min_hi = 0;
+                               return ec;
+                       }
+
+                       for (best = 0, d = bmax; d >= bmin; d -= 2) {
+                               dd = d > bmid ? d - bmid: bmid - d;
+                               i1 = kvdb[d];
+                               i2 = i1 - d;
+                               v = (lim1 - i1) + (lim2 - i2) - dd;
+
+                               if (v > XDL_K_HEUR * ec && v > best &&
+                                   off1 < i1 && i1 <= lim1 - xenv->snake_cnt &&
+                                   off2 < i2 && i2 <= lim2 - xenv->snake_cnt) {
+                                       for (k = 0; ha1[i1 + k] == ha2[i2 + k]; k++)
+                                               if (k == xenv->snake_cnt - 1) {
+                                                       best = v;
+                                                       spl->i1 = i1;
+                                                       spl->i2 = i2;
+                                                       break;
+                                               }
+                               }
+                       }
+                       if (best > 0) {
+                               spl->min_lo = 0;
+                               spl->min_hi = 1;
+                               return ec;
+                       }
+               }
+
+               /*
+                * Enough is enough. We spent too much time here and now we
+                * collect the furthest reaching path using the (i1 + i2)
+                * measure.
+                */
+               if (ec >= xenv->mxcost) {
+                       long fbest, fbest1, bbest, bbest1;
+
+                       fbest = fbest1 = -1;
+                       for (d = fmax; d >= fmin; d -= 2) {
+                               i1 = XDL_MIN(kvdf[d], lim1);
+                               i2 = i1 - d;
+                               if (lim2 < i2)
+                                       i1 = lim2 + d, i2 = lim2;
+                               if (fbest < i1 + i2) {
+                                       fbest = i1 + i2;
+                                       fbest1 = i1;
+                               }
+                       }
+
+                       bbest = bbest1 = XDL_LINE_MAX;
+                       for (d = bmax; d >= bmin; d -= 2) {
+                               i1 = XDL_MAX(off1, kvdb[d]);
+                               i2 = i1 - d;
+                               if (i2 < off2)
+                                       i1 = off2 + d, i2 = off2;
+                               if (i1 + i2 < bbest) {
+                                       bbest = i1 + i2;
+                                       bbest1 = i1;
+                               }
+                       }
+
+                       if ((lim1 + lim2) - bbest < fbest - (off1 + off2)) {
+                               spl->i1 = fbest1;
+                               spl->i2 = fbest - fbest1;
+                               spl->min_lo = 1;
+                               spl->min_hi = 0;
+                       } else {
+                               spl->i1 = bbest1;
+                               spl->i2 = bbest - bbest1;
+                               spl->min_lo = 0;
+                               spl->min_hi = 1;
+                       }
+                       return ec;
+               }
+       }
+}
+
+
+/*
+ * Rule: "Divide et Impera" (divide & conquer). Recursively split the box in
+ * sub-boxes by calling the box splitting function. Note that the real job
+ * (marking changed lines) is done in the two boundary reaching checks.
+ */
+int xdl_recs_cmp(diffdata_t *dd1, long off1, long lim1,
+                diffdata_t *dd2, long off2, long lim2,
+                long *kvdf, long *kvdb, int need_min, xdalgoenv_t *xenv) {
+       unsigned long const *ha1 = dd1->ha, *ha2 = dd2->ha;
+
+       /*
+        * Shrink the box by walking through each diagonal snake (SW and NE).
+        */
+       for (; off1 < lim1 && off2 < lim2 && ha1[off1] == ha2[off2]; off1++, off2++);
+       for (; off1 < lim1 && off2 < lim2 && ha1[lim1 - 1] == ha2[lim2 - 1]; lim1--, lim2--);
+
+       /*
+        * If one dimension is empty, then all records on the other one must
+        * be obviously changed.
+        */
+       if (off1 == lim1) {
+               char *rchg2 = dd2->rchg;
+               long *rindex2 = dd2->rindex;
+
+               for (; off2 < lim2; off2++)
+                       rchg2[rindex2[off2]] = 1;
+       } else if (off2 == lim2) {
+               char *rchg1 = dd1->rchg;
+               long *rindex1 = dd1->rindex;
+
+               for (; off1 < lim1; off1++)
+                       rchg1[rindex1[off1]] = 1;
+       } else {
+               xdpsplit_t spl;
+               spl.i1 = spl.i2 = 0;
+
+               /*
+                * Divide ...
+                */
+               if (xdl_split(ha1, off1, lim1, ha2, off2, lim2, kvdf, kvdb,
+                             need_min, &spl, xenv) < 0) {
+
+                       return -1;
+               }
+
+               /*
+                * ... et Impera.
+                */
+               if (xdl_recs_cmp(dd1, off1, spl.i1, dd2, off2, spl.i2,
+                                kvdf, kvdb, spl.min_lo, xenv) < 0 ||
+                   xdl_recs_cmp(dd1, spl.i1, lim1, dd2, spl.i2, lim2,
+                                kvdf, kvdb, spl.min_hi, xenv) < 0) {
+
+                       return -1;
+               }
+       }
+
+       return 0;
+}
+
+
+int xdl_do_diff(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp,
+               xdfenv_t *xe) {
+       long ndiags;
+       long *kvd, *kvdf, *kvdb;
+       xdalgoenv_t xenv;
+       diffdata_t dd1, dd2;
+       int res;
+
+       if (xdl_prepare_env(mf1, mf2, xpp, xe) < 0)
+               return -1;
+
+       if (XDF_DIFF_ALG(xpp->flags) == XDF_PATIENCE_DIFF) {
+               res = xdl_do_patience_diff(xpp, xe);
+               goto out;
+       }
+
+       if (XDF_DIFF_ALG(xpp->flags) == XDF_HISTOGRAM_DIFF) {
+               res = xdl_do_histogram_diff(xpp, xe);
+               goto out;
+       }
+
+       /*
+        * Allocate and setup K vectors to be used by the differential
+        * algorithm.
+        *
+        * One is to store the forward path and one to store the backward path.
+        */
+       ndiags = xe->xdf1.nreff + xe->xdf2.nreff + 3;
+       if (!XDL_ALLOC_ARRAY(kvd, 2 * ndiags + 2)) {
+
+               xdl_free_env(xe);
+               return -1;
+       }
+       kvdf = kvd;
+       kvdb = kvdf + ndiags;
+       kvdf += xe->xdf2.nreff + 1;
+       kvdb += xe->xdf2.nreff + 1;
+
+       xenv.mxcost = xdl_bogosqrt(ndiags);
+       if (xenv.mxcost < XDL_MAX_COST_MIN)
+               xenv.mxcost = XDL_MAX_COST_MIN;
+       xenv.snake_cnt = XDL_SNAKE_CNT;
+       xenv.heur_min = XDL_HEUR_MIN_COST;
+
+       dd1.nrec = xe->xdf1.nreff;
+       dd1.ha = xe->xdf1.ha;
+       dd1.rchg = xe->xdf1.rchg;
+       dd1.rindex = xe->xdf1.rindex;
+       dd2.nrec = xe->xdf2.nreff;
+       dd2.ha = xe->xdf2.ha;
+       dd2.rchg = xe->xdf2.rchg;
+       dd2.rindex = xe->xdf2.rindex;
+
+       res = xdl_recs_cmp(&dd1, 0, dd1.nrec, &dd2, 0, dd2.nrec,
+                          kvdf, kvdb, (xpp->flags & XDF_NEED_MINIMAL) != 0,
+                          &xenv);
+       xdl_free(kvd);
+ out:
+       if (res < 0)
+               xdl_free_env(xe);
+
+       return res;
+}
+
+
+static xdchange_t *xdl_add_change(xdchange_t *xscr, long i1, long i2, long chg1, long chg2) {
+       xdchange_t *xch;
+
+       if (!(xch = (xdchange_t *) xdl_malloc(sizeof(xdchange_t))))
+               return NULL;
+
+       xch->next = xscr;
+       xch->i1 = i1;
+       xch->i2 = i2;
+       xch->chg1 = chg1;
+       xch->chg2 = chg2;
+       xch->ignore = 0;
+
+       return xch;
+}
+
+
+static int recs_match(xrecord_t *rec1, xrecord_t *rec2)
+{
+       return (rec1->ha == rec2->ha);
+}
+
+/*
+ * If a line is indented more than this, get_indent() just returns this value.
+ * This avoids having to do absurd amounts of work for data that are not
+ * human-readable text, and also ensures that the output of get_indent fits
+ * within an int.
+ */
+#define MAX_INDENT 200
+
+/*
+ * Return the amount of indentation of the specified line, treating TAB as 8
+ * columns. Return -1 if line is empty or contains only whitespace. Clamp the
+ * output value at MAX_INDENT.
+ */
+static int get_indent(xrecord_t *rec)
+{
+       long i;
+       int ret = 0;
+
+       for (i = 0; i < rec->size; i++) {
+               char c = rec->ptr[i];
+
+               if (!XDL_ISSPACE(c))
+                       return ret;
+               else if (c == ' ')
+                       ret += 1;
+               else if (c == '\t')
+                       ret += 8 - ret % 8;
+               /* ignore other whitespace characters */
+
+               if (ret >= MAX_INDENT)
+                       return MAX_INDENT;
+       }
+
+       /* The line contains only whitespace. */
+       return -1;
+}
+
+/*
+ * If more than this number of consecutive blank rows are found, just return
+ * this value. This avoids requiring O(N^2) work for pathological cases, and
+ * also ensures that the output of score_split fits in an int.
+ */
+#define MAX_BLANKS 20
+
+/* Characteristics measured about a hypothetical split position. */
+struct split_measurement {
+       /*
+        * Is the split at the end of the file (aside from any blank lines)?
+        */
+       int end_of_file;
+
+       /*
+        * How much is the line immediately following the split indented (or -1
+        * if the line is blank):
+        */
+       int indent;
+
+       /*
+        * How many consecutive lines above the split are blank?
+        */
+       int pre_blank;
+
+       /*
+        * How much is the nearest non-blank line above the split indented (or
+        * -1 if there is no such line)?
+        */
+       int pre_indent;
+
+       /*
+        * How many lines after the line following the split are blank?
+        */
+       int post_blank;
+
+       /*
+        * How much is the nearest non-blank line after the line following the
+        * split indented (or -1 if there is no such line)?
+        */
+       int post_indent;
+};
+
+struct split_score {
+       /* The effective indent of this split (smaller is preferred). */
+       int effective_indent;
+
+       /* Penalty for this split (smaller is preferred). */
+       int penalty;
+};
+
+/*
+ * Fill m with information about a hypothetical split of xdf above line split.
+ */
+static void measure_split(const xdfile_t *xdf, long split,
+                         struct split_measurement *m)
+{
+       long i;
+
+       if (split >= xdf->nrec) {
+               m->end_of_file = 1;
+               m->indent = -1;
+       } else {
+               m->end_of_file = 0;
+               m->indent = get_indent(xdf->recs[split]);
+       }
+
+       m->pre_blank = 0;
+       m->pre_indent = -1;
+       for (i = split - 1; i >= 0; i--) {
+               m->pre_indent = get_indent(xdf->recs[i]);
+               if (m->pre_indent != -1)
+                       break;
+               m->pre_blank += 1;
+               if (m->pre_blank == MAX_BLANKS) {
+                       m->pre_indent = 0;
+                       break;
+               }
+       }
+
+       m->post_blank = 0;
+       m->post_indent = -1;
+       for (i = split + 1; i < xdf->nrec; i++) {
+               m->post_indent = get_indent(xdf->recs[i]);
+               if (m->post_indent != -1)
+                       break;
+               m->post_blank += 1;
+               if (m->post_blank == MAX_BLANKS) {
+                       m->post_indent = 0;
+                       break;
+               }
+       }
+}
+
+/*
+ * The empirically-determined weight factors used by score_split() below.
+ * Larger values means that the position is a less favorable place to split.
+ *
+ * Note that scores are only ever compared against each other, so multiplying
+ * all of these weight/penalty values by the same factor wouldn't change the
+ * heuristic's behavior. Still, we need to set that arbitrary scale *somehow*.
+ * In practice, these numbers are chosen to be large enough that they can be
+ * adjusted relative to each other with sufficient precision despite using
+ * integer math.
+ */
+
+/* Penalty if there are no non-blank lines before the split */
+#define START_OF_FILE_PENALTY 1
+
+/* Penalty if there are no non-blank lines after the split */
+#define END_OF_FILE_PENALTY 21
+
+/* Multiplier for the number of blank lines around the split */
+#define TOTAL_BLANK_WEIGHT (-30)
+
+/* Multiplier for the number of blank lines after the split */
+#define POST_BLANK_WEIGHT 6
+
+/*
+ * Penalties applied if the line is indented more than its predecessor
+ */
+#define RELATIVE_INDENT_PENALTY (-4)
+#define RELATIVE_INDENT_WITH_BLANK_PENALTY 10
+
+/*
+ * Penalties applied if the line is indented less than both its predecessor and
+ * its successor
+ */
+#define RELATIVE_OUTDENT_PENALTY 24
+#define RELATIVE_OUTDENT_WITH_BLANK_PENALTY 17
+
+/*
+ * Penalties applied if the line is indented less than its predecessor but not
+ * less than its successor
+ */
+#define RELATIVE_DEDENT_PENALTY 23
+#define RELATIVE_DEDENT_WITH_BLANK_PENALTY 17
+
+/*
+ * We only consider whether the sum of the effective indents for splits are
+ * less than (-1), equal to (0), or greater than (+1) each other. The resulting
+ * value is multiplied by the following weight and combined with the penalty to
+ * determine the better of two scores.
+ */
+#define INDENT_WEIGHT 60
+
+/*
+ * How far do we slide a hunk at most?
+ */
+#define INDENT_HEURISTIC_MAX_SLIDING 100
+
+/*
+ * Compute a badness score for the hypothetical split whose measurements are
+ * stored in m. The weight factors were determined empirically using the tools
+ * and corpus described in
+ *
+ *     https://github.com/mhagger/diff-slider-tools
+ *
+ * Also see that project if you want to improve the weights based on, for
+ * example, a larger or more diverse corpus.
+ */
+static void score_add_split(const struct split_measurement *m, struct split_score *s)
+{
+       /*
+        * A place to accumulate penalty factors (positive makes this index more
+        * favored):
+        */
+       int post_blank, total_blank, indent, any_blanks;
+
+       if (m->pre_indent == -1 && m->pre_blank == 0)
+               s->penalty += START_OF_FILE_PENALTY;
+
+       if (m->end_of_file)
+               s->penalty += END_OF_FILE_PENALTY;
+
+       /*
+        * Set post_blank to the number of blank lines following the split,
+        * including the line immediately after the split:
+        */
+       post_blank = (m->indent == -1) ? 1 + m->post_blank : 0;
+       total_blank = m->pre_blank + post_blank;
+
+       /* Penalties based on nearby blank lines: */
+       s->penalty += TOTAL_BLANK_WEIGHT * total_blank;
+       s->penalty += POST_BLANK_WEIGHT * post_blank;
+
+       if (m->indent != -1)
+               indent = m->indent;
+       else
+               indent = m->post_indent;
+
+       any_blanks = (total_blank != 0);
+
+       /* Note that the effective indent is -1 at the end of the file: */
+       s->effective_indent += indent;
+
+       if (indent == -1) {
+               /* No additional adjustments needed. */
+       } else if (m->pre_indent == -1) {
+               /* No additional adjustments needed. */
+       } else if (indent > m->pre_indent) {
+               /*
+                * The line is indented more than its predecessor.
+                */
+               s->penalty += any_blanks ?
+                       RELATIVE_INDENT_WITH_BLANK_PENALTY :
+                       RELATIVE_INDENT_PENALTY;
+       } else if (indent == m->pre_indent) {
+               /*
+                * The line has the same indentation level as its predecessor.
+                * No additional adjustments needed.
+                */
+       } else {
+               /*
+                * The line is indented less than its predecessor. It could be
+                * the block terminator of the previous block, but it could
+                * also be the start of a new block (e.g., an "else" block, or
+                * maybe the previous block didn't have a block terminator).
+                * Try to distinguish those cases based on what comes next:
+                */
+               if (m->post_indent != -1 && m->post_indent > indent) {
+                       /*
+                        * The following line is indented more. So it is likely
+                        * that this line is the start of a block.
+                        */
+                       s->penalty += any_blanks ?
+                               RELATIVE_OUTDENT_WITH_BLANK_PENALTY :
+                               RELATIVE_OUTDENT_PENALTY;
+               } else {
+                       /*
+                        * That was probably the end of a block.
+                        */
+                       s->penalty += any_blanks ?
+                               RELATIVE_DEDENT_WITH_BLANK_PENALTY :
+                               RELATIVE_DEDENT_PENALTY;
+               }
+       }
+}
+
+static int score_cmp(struct split_score *s1, struct split_score *s2)
+{
+       /* -1 if s1.effective_indent < s2->effective_indent, etc. */
+       int cmp_indents = ((s1->effective_indent > s2->effective_indent) -
+                          (s1->effective_indent < s2->effective_indent));
+
+       return INDENT_WEIGHT * cmp_indents + (s1->penalty - s2->penalty);
+}
+
+/*
+ * Represent a group of changed lines in an xdfile_t (i.e., a contiguous group
+ * of lines that was inserted or deleted from the corresponding version of the
+ * file). We consider there to be such a group at the beginning of the file, at
+ * the end of the file, and between any two unchanged lines, though most such
+ * groups will usually be empty.
+ *
+ * If the first line in a group is equal to the line following the group, then
+ * the group can be slid down. Similarly, if the last line in a group is equal
+ * to the line preceding the group, then the group can be slid up. See
+ * group_slide_down() and group_slide_up().
+ *
+ * Note that loops that are testing for changed lines in xdf->rchg do not need
+ * index bounding since the array is prepared with a zero at position -1 and N.
+ */
+struct xdlgroup {
+       /*
+        * The index of the first changed line in the group, or the index of
+        * the unchanged line above which the (empty) group is located.
+        */
+       long start;
+
+       /*
+        * The index of the first unchanged line after the group. For an empty
+        * group, end is equal to start.
+        */
+       long end;
+};
+
+/*
+ * Initialize g to point at the first group in xdf.
+ */
+static void group_init(xdfile_t *xdf, struct xdlgroup *g)
+{
+       g->start = g->end = 0;
+       while (xdf->rchg[g->end])
+               g->end++;
+}
+
+/*
+ * Move g to describe the next (possibly empty) group in xdf and return 0. If g
+ * is already at the end of the file, do nothing and return -1.
+ */
+static inline int group_next(xdfile_t *xdf, struct xdlgroup *g)
+{
+       if (g->end == xdf->nrec)
+               return -1;
+
+       g->start = g->end + 1;
+       for (g->end = g->start; xdf->rchg[g->end]; g->end++)
+               ;
+
+       return 0;
+}
+
+/*
+ * Move g to describe the previous (possibly empty) group in xdf and return 0.
+ * If g is already at the beginning of the file, do nothing and return -1.
+ */
+static inline int group_previous(xdfile_t *xdf, struct xdlgroup *g)
+{
+       if (g->start == 0)
+               return -1;
+
+       g->end = g->start - 1;
+       for (g->start = g->end; xdf->rchg[g->start - 1]; g->start--)
+               ;
+
+       return 0;
+}
+
+/*
+ * If g can be slid toward the end of the file, do so, and if it bumps into a
+ * following group, expand this group to include it. Return 0 on success or -1
+ * if g cannot be slid down.
+ */
+static int group_slide_down(xdfile_t *xdf, struct xdlgroup *g)
+{
+       if (g->end < xdf->nrec &&
+           recs_match(xdf->recs[g->start], xdf->recs[g->end])) {
+               xdf->rchg[g->start++] = 0;
+               xdf->rchg[g->end++] = 1;
+
+               while (xdf->rchg[g->end])
+                       g->end++;
+
+               return 0;
+       } else {
+               return -1;
+       }
+}
+
+/*
+ * If g can be slid toward the beginning of the file, do so, and if it bumps
+ * into a previous group, expand this group to include it. Return 0 on success
+ * or -1 if g cannot be slid up.
+ */
+static int group_slide_up(xdfile_t *xdf, struct xdlgroup *g)
+{
+       if (g->start > 0 &&
+           recs_match(xdf->recs[g->start - 1], xdf->recs[g->end - 1])) {
+               xdf->rchg[--g->start] = 1;
+               xdf->rchg[--g->end] = 0;
+
+               while (xdf->rchg[g->start - 1])
+                       g->start--;
+
+               return 0;
+       } else {
+               return -1;
+       }
+}
+
+/*
+ * Move back and forward change groups for a consistent and pretty diff output.
+ * This also helps in finding joinable change groups and reducing the diff
+ * size.
+ */
+int xdl_change_compact(xdfile_t *xdf, xdfile_t *xdfo, long flags) {
+       struct xdlgroup g, go;
+       long earliest_end, end_matching_other;
+       long groupsize;
+
+       group_init(xdf, &g);
+       group_init(xdfo, &go);
+
+       while (1) {
+               /*
+                * If the group is empty in the to-be-compacted file, skip it:
+                */
+               if (g.end == g.start)
+                       goto next;
+
+               /*
+                * Now shift the change up and then down as far as possible in
+                * each direction. If it bumps into any other changes, merge
+                * them.
+                */
+               do {
+                       groupsize = g.end - g.start;
+
+                       /*
+                        * Keep track of the last "end" index that causes this
+                        * group to align with a group of changed lines in the
+                        * other file. -1 indicates that we haven't found such
+                        * a match yet:
+                        */
+                       end_matching_other = -1;
+
+                       /* Shift the group backward as much as possible: */
+                       while (!group_slide_up(xdf, &g))
+                               if (group_previous(xdfo, &go))
+                                       BUG("group sync broken sliding up");
+
+                       /*
+                        * This is this highest that this group can be shifted.
+                        * Record its end index:
+                        */
+                       earliest_end = g.end;
+
+                       if (go.end > go.start)
+                               end_matching_other = g.end;
+
+                       /* Now shift the group forward as far as possible: */
+                       while (1) {
+                               if (group_slide_down(xdf, &g))
+                                       break;
+                               if (group_next(xdfo, &go))
+                                       BUG("group sync broken sliding down");
+
+                               if (go.end > go.start)
+                                       end_matching_other = g.end;
+                       }
+               } while (groupsize != g.end - g.start);
+
+               /*
+                * If the group can be shifted, then we can possibly use this
+                * freedom to produce a more intuitive diff.
+                *
+                * The group is currently shifted as far down as possible, so
+                * the heuristics below only have to handle upwards shifts.
+                */
+
+               if (g.end == earliest_end) {
+                       /* no shifting was possible */
+               } else if (end_matching_other != -1) {
+                       /*
+                        * Move the possibly merged group of changes back to
+                        * line up with the last group of changes from the
+                        * other file that it can align with.
+                        */
+                       while (go.end == go.start) {
+                               if (group_slide_up(xdf, &g))
+                                       BUG("match disappeared");
+                               if (group_previous(xdfo, &go))
+                                       BUG("group sync broken sliding to match");
+                       }
+               } else if (flags & XDF_INDENT_HEURISTIC) {
+                       /*
+                        * Indent heuristic: a group of pure add/delete lines
+                        * implies two splits, one between the end of the
+                        * "before" context and the start of the group, and
+                        * another between the end of the group and the
+                        * beginning of the "after" context. Some splits are
+                        * aesthetically better and some are worse. We compute
+                        * a badness "score" for each split, and add the scores
+                        * for the two splits to define a "score" for each
+                        * position that the group can be shifted to. Then we
+                        * pick the shift with the lowest score.
+                        */
+                       long shift, best_shift = -1;
+                       struct split_score best_score;
+
+                       shift = earliest_end;
+                       if (g.end - groupsize - 1 > shift)
+                               shift = g.end - groupsize - 1;
+                       if (g.end - INDENT_HEURISTIC_MAX_SLIDING > shift)
+                               shift = g.end - INDENT_HEURISTIC_MAX_SLIDING;
+                       for (; shift <= g.end; shift++) {
+                               struct split_measurement m;
+                               struct split_score score = {0, 0};
+
+                               measure_split(xdf, shift, &m);
+                               score_add_split(&m, &score);
+                               measure_split(xdf, shift - groupsize, &m);
+                               score_add_split(&m, &score);
+                               if (best_shift == -1 ||
+                                   score_cmp(&score, &best_score) <= 0) {
+                                       best_score.effective_indent = score.effective_indent;
+                                       best_score.penalty = score.penalty;
+                                       best_shift = shift;
+                               }
+                       }
+
+                       while (g.end > best_shift) {
+                               if (group_slide_up(xdf, &g))
+                                       BUG("best shift unreached");
+                               if (group_previous(xdfo, &go))
+                                       BUG("group sync broken sliding to blank line");
+                       }
+               }
+
+       next:
+               /* Move past the just-processed group: */
+               if (group_next(xdf, &g))
+                       break;
+               if (group_next(xdfo, &go))
+                       BUG("group sync broken moving to next group");
+       }
+
+       if (!group_next(xdfo, &go))
+               BUG("group sync broken at end of file");
+
+       return 0;
+}
+
+
+int xdl_build_script(xdfenv_t *xe, xdchange_t **xscr) {
+       xdchange_t *cscr = NULL, *xch;
+       char *rchg1 = xe->xdf1.rchg, *rchg2 = xe->xdf2.rchg;
+       long i1, i2, l1, l2;
+
+       /*
+        * Trivial. Collects "groups" of changes and creates an edit script.
+        */
+       for (i1 = xe->xdf1.nrec, i2 = xe->xdf2.nrec; i1 >= 0 || i2 >= 0; i1--, i2--)
+               if (rchg1[i1 - 1] || rchg2[i2 - 1]) {
+                       for (l1 = i1; rchg1[i1 - 1]; i1--);
+                       for (l2 = i2; rchg2[i2 - 1]; i2--);
+
+                       if (!(xch = xdl_add_change(cscr, i1, i2, l1 - i1, l2 - i2))) {
+                               xdl_free_script(cscr);
+                               return -1;
+                       }
+                       cscr = xch;
+               }
+
+       *xscr = cscr;
+
+       return 0;
+}
+
+
+void xdl_free_script(xdchange_t *xscr) {
+       xdchange_t *xch;
+
+       while ((xch = xscr) != NULL) {
+               xscr = xscr->next;
+               xdl_free(xch);
+       }
+}
+
+static int xdl_call_hunk_func(xdfenv_t *xe UNUSED, xdchange_t *xscr, xdemitcb_t *ecb,
+                             xdemitconf_t const *xecfg)
+{
+       xdchange_t *xch, *xche;
+
+       for (xch = xscr; xch; xch = xche->next) {
+               xche = xdl_get_hunk(&xch, xecfg);
+               if (!xch)
+                       break;
+               if (xecfg->hunk_func(xch->i1, xche->i1 + xche->chg1 - xch->i1,
+                                    xch->i2, xche->i2 + xche->chg2 - xch->i2,
+                                    ecb->priv) < 0)
+                       return -1;
+       }
+       return 0;
+}
+
+static void xdl_mark_ignorable_lines(xdchange_t *xscr, xdfenv_t *xe, long flags)
+{
+       xdchange_t *xch;
+
+       for (xch = xscr; xch; xch = xch->next) {
+               int ignore = 1;
+               xrecord_t **rec;
+               long i;
+
+               rec = &xe->xdf1.recs[xch->i1];
+               for (i = 0; i < xch->chg1 && ignore; i++)
+                       ignore = xdl_blankline(rec[i]->ptr, rec[i]->size, flags);
+
+               rec = &xe->xdf2.recs[xch->i2];
+               for (i = 0; i < xch->chg2 && ignore; i++)
+                       ignore = xdl_blankline(rec[i]->ptr, rec[i]->size, flags);
+
+               xch->ignore = ignore;
+       }
+}
+
+static int record_matches_regex(xrecord_t *rec, xpparam_t const *xpp) {
+       regmatch_t regmatch;
+       int i;
+
+       for (i = 0; i < xpp->ignore_regex_nr; i++)
+               if (!regexec_buf(xpp->ignore_regex[i], rec->ptr, rec->size, 1,
+                                &regmatch, 0))
+                       return 1;
+
+       return 0;
+}
+
+static void xdl_mark_ignorable_regex(xdchange_t *xscr, const xdfenv_t *xe,
+                                    xpparam_t const *xpp)
+{
+       xdchange_t *xch;
+
+       for (xch = xscr; xch; xch = xch->next) {
+               xrecord_t **rec;
+               int ignore = 1;
+               long i;
+
+               /*
+                * Do not override --ignore-blank-lines.
+                */
+               if (xch->ignore)
+                       continue;
+
+               rec = &xe->xdf1.recs[xch->i1];
+               for (i = 0; i < xch->chg1 && ignore; i++)
+                       ignore = record_matches_regex(rec[i], xpp);
+
+               rec = &xe->xdf2.recs[xch->i2];
+               for (i = 0; i < xch->chg2 && ignore; i++)
+                       ignore = record_matches_regex(rec[i], xpp);
+
+               xch->ignore = ignore;
+       }
+}
+
+int xdl_diff(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp,
+            xdemitconf_t const *xecfg, xdemitcb_t *ecb) {
+       xdchange_t *xscr;
+       xdfenv_t xe;
+       emit_func_t ef = xecfg->hunk_func ? xdl_call_hunk_func : xdl_emit_diff;
+
+       if (xdl_do_diff(mf1, mf2, xpp, &xe) < 0) {
+
+               return -1;
+       }
+       if (xdl_change_compact(&xe.xdf1, &xe.xdf2, xpp->flags) < 0 ||
+           xdl_change_compact(&xe.xdf2, &xe.xdf1, xpp->flags) < 0 ||
+           xdl_build_script(&xe, &xscr) < 0) {
+
+               xdl_free_env(&xe);
+               return -1;
+       }
+       if (xscr) {
+               if (xpp->flags & XDF_IGNORE_BLANK_LINES)
+                       xdl_mark_ignorable_lines(xscr, &xe, xpp->flags);
+
+               if (xpp->ignore_regex)
+                       xdl_mark_ignorable_regex(xscr, &xe, xpp);
+
+               if (ef(&xe, xscr, ecb, xecfg) < 0) {
+
+                       xdl_free_script(xscr);
+                       xdl_free_env(&xe);
+                       return -1;
+               }
+               xdl_free_script(xscr);
+       }
+       xdl_free_env(&xe);
+
+       return 0;
+}
diff --git a/xdiffi.h b/xdiffi.h
new file mode 100644 (file)
index 0000000..126c9d8
--- /dev/null
+++ b/xdiffi.h
@@ -0,0 +1,62 @@
+/*
+ *  LibXDiff by Davide Libenzi ( File Differential Library )
+ *  Copyright (C) 2003  Davide Libenzi
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Lesser General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 2.1 of the License, or (at your option) any later version.
+ *
+ *  This library is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public
+ *  License along with this library; if not, see
+ *  <http://www.gnu.org/licenses/>.
+ *
+ *  Davide Libenzi <davidel@xmailserver.org>
+ *
+ */
+
+#if !defined(XDIFFI_H)
+#define XDIFFI_H
+
+
+typedef struct s_diffdata {
+       long nrec;
+       unsigned long const *ha;
+       long *rindex;
+       char *rchg;
+} diffdata_t;
+
+typedef struct s_xdalgoenv {
+       long mxcost;
+       long snake_cnt;
+       long heur_min;
+} xdalgoenv_t;
+
+typedef struct s_xdchange {
+       struct s_xdchange *next;
+       long i1, i2;
+       long chg1, chg2;
+       int ignore;
+} xdchange_t;
+
+
+
+int xdl_recs_cmp(diffdata_t *dd1, long off1, long lim1,
+                diffdata_t *dd2, long off2, long lim2,
+                long *kvdf, long *kvdb, int need_min, xdalgoenv_t *xenv);
+int xdl_do_diff(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp,
+               xdfenv_t *xe);
+int xdl_change_compact(xdfile_t *xdf, xdfile_t *xdfo, long flags);
+int xdl_build_script(xdfenv_t *xe, xdchange_t **xscr);
+void xdl_free_script(xdchange_t *xscr);
+int xdl_emit_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
+                 xdemitconf_t const *xecfg);
+int xdl_do_patience_diff(xpparam_t const *xpp, xdfenv_t *env);
+int xdl_do_histogram_diff(xpparam_t const *xpp, xdfenv_t *env);
+
+#endif /* #if !defined(XDIFFI_H) */
diff --git a/xemit.c b/xemit.c
new file mode 100644 (file)
index 0000000..75f0fe4
--- /dev/null
+++ b/xemit.c
@@ -0,0 +1,330 @@
+/*
+ *  LibXDiff by Davide Libenzi ( File Differential Library )
+ *  Copyright (C) 2003 Davide Libenzi
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Lesser General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 2.1 of the License, or (at your option) any later version.
+ *
+ *  This library is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public
+ *  License along with this library; if not, see
+ *  <http://www.gnu.org/licenses/>.
+ *
+ *  Davide Libenzi <davidel@xmailserver.org>
+ *
+ */
+
+#include "xinclude.h"
+
+static long xdl_get_rec(xdfile_t *xdf, long ri, char const **rec) {
+
+       *rec = xdf->recs[ri]->ptr;
+
+       return xdf->recs[ri]->size;
+}
+
+
+static int xdl_emit_record(xdfile_t *xdf, long ri, char const *pre, xdemitcb_t *ecb) {
+       long size, psize = strlen(pre);
+       char const *rec;
+
+       size = xdl_get_rec(xdf, ri, &rec);
+       if (xdl_emit_diffrec(rec, size, pre, psize, ecb) < 0) {
+
+               return -1;
+       }
+
+       return 0;
+}
+
+
+/*
+ * Starting at the passed change atom, find the latest change atom to be included
+ * inside the differential hunk according to the specified configuration.
+ * Also advance xscr if the first changes must be discarded.
+ */
+xdchange_t *xdl_get_hunk(xdchange_t **xscr, xdemitconf_t const *xecfg)
+{
+       xdchange_t *xch, *xchp, *lxch;
+       long max_common = 2 * xecfg->ctxlen + xecfg->interhunkctxlen;
+       long max_ignorable = xecfg->ctxlen;
+       unsigned long ignored = 0; /* number of ignored blank lines */
+
+       /* remove ignorable changes that are too far before other changes */
+       for (xchp = *xscr; xchp && xchp->ignore; xchp = xchp->next) {
+               xch = xchp->next;
+
+               if (xch == NULL ||
+                   xch->i1 - (xchp->i1 + xchp->chg1) >= max_ignorable)
+                       *xscr = xch;
+       }
+
+       if (!*xscr)
+               return NULL;
+
+       lxch = *xscr;
+
+       for (xchp = *xscr, xch = xchp->next; xch; xchp = xch, xch = xch->next) {
+               long distance = xch->i1 - (xchp->i1 + xchp->chg1);
+               if (distance > max_common)
+                       break;
+
+               if (distance < max_ignorable && (!xch->ignore || lxch == xchp)) {
+                       lxch = xch;
+                       ignored = 0;
+               } else if (distance < max_ignorable && xch->ignore) {
+                       ignored += xch->chg2;
+               } else if (lxch != xchp &&
+                          xch->i1 + ignored - (lxch->i1 + lxch->chg1) > max_common) {
+                       break;
+               } else if (!xch->ignore) {
+                       lxch = xch;
+                       ignored = 0;
+               } else {
+                       ignored += xch->chg2;
+               }
+       }
+
+       return lxch;
+}
+
+
+static long def_ff(const char *rec, long len, char *buf, long sz)
+{
+       if (len > 0 &&
+                       (isalpha((unsigned char)*rec) || /* identifier? */
+                        *rec == '_' || /* also identifier? */
+                        *rec == '$')) { /* identifiers from VMS and other esoterico */
+               if (len > sz)
+                       len = sz;
+               while (0 < len && isspace((unsigned char)rec[len - 1]))
+                       len--;
+               memcpy(buf, rec, len);
+               return len;
+       }
+       return -1;
+}
+
+static long match_func_rec(xdfile_t *xdf, xdemitconf_t const *xecfg, long ri,
+                          char *buf, long sz)
+{
+       const char *rec;
+       long len = xdl_get_rec(xdf, ri, &rec);
+       if (!xecfg->find_func)
+               return def_ff(rec, len, buf, sz);
+       return xecfg->find_func(rec, len, buf, sz, xecfg->find_func_priv);
+}
+
+static int is_func_rec(xdfile_t *xdf, xdemitconf_t const *xecfg, long ri)
+{
+       char dummy[1];
+       return match_func_rec(xdf, xecfg, ri, dummy, sizeof(dummy)) >= 0;
+}
+
+struct func_line {
+       long len;
+       char buf[80];
+};
+
+static long get_func_line(xdfenv_t *xe, xdemitconf_t const *xecfg,
+                         struct func_line *func_line, long start, long limit)
+{
+       long l, size, step = (start > limit) ? -1 : 1;
+       char *buf, dummy[1];
+
+       buf = func_line ? func_line->buf : dummy;
+       size = func_line ? sizeof(func_line->buf) : sizeof(dummy);
+
+       for (l = start; l != limit && 0 <= l && l < xe->xdf1.nrec; l += step) {
+               long len = match_func_rec(&xe->xdf1, xecfg, l, buf, size);
+               if (len >= 0) {
+                       if (func_line)
+                               func_line->len = len;
+                       return l;
+               }
+       }
+       return -1;
+}
+
+static int is_empty_rec(xdfile_t *xdf, long ri)
+{
+       const char *rec;
+       long len = xdl_get_rec(xdf, ri, &rec);
+
+       while (len > 0 && XDL_ISSPACE(*rec)) {
+               rec++;
+               len--;
+       }
+       return !len;
+}
+
+int xdl_emit_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
+                 xdemitconf_t const *xecfg) {
+       long s1, s2, e1, e2, lctx;
+       xdchange_t *xch, *xche;
+       long funclineprev = -1;
+       struct func_line func_line = { 0 };
+
+       for (xch = xscr; xch; xch = xche->next) {
+               xdchange_t *xchp = xch;
+               xche = xdl_get_hunk(&xch, xecfg);
+               if (!xch)
+                       break;
+
+pre_context_calculation:
+               s1 = XDL_MAX(xch->i1 - xecfg->ctxlen, 0);
+               s2 = XDL_MAX(xch->i2 - xecfg->ctxlen, 0);
+
+               if (xecfg->flags & XDL_EMIT_FUNCCONTEXT) {
+                       long fs1, i1 = xch->i1;
+
+                       /* Appended chunk? */
+                       if (i1 >= xe->xdf1.nrec) {
+                               long i2 = xch->i2;
+
+                               /*
+                                * We don't need additional context if
+                                * a whole function was added.
+                                */
+                               while (i2 < xe->xdf2.nrec) {
+                                       if (is_func_rec(&xe->xdf2, xecfg, i2))
+                                               goto post_context_calculation;
+                                       i2++;
+                               }
+
+                               /*
+                                * Otherwise get more context from the
+                                * pre-image.
+                                */
+                               i1 = xe->xdf1.nrec - 1;
+                       }
+
+                       fs1 = get_func_line(xe, xecfg, NULL, i1, -1);
+                       while (fs1 > 0 && !is_empty_rec(&xe->xdf1, fs1 - 1) &&
+                              !is_func_rec(&xe->xdf1, xecfg, fs1 - 1))
+                               fs1--;
+                       if (fs1 < 0)
+                               fs1 = 0;
+                       if (fs1 < s1) {
+                               s2 = XDL_MAX(s2 - (s1 - fs1), 0);
+                               s1 = fs1;
+
+                               /*
+                                * Did we extend context upwards into an
+                                * ignored change?
+                                */
+                               while (xchp != xch &&
+                                      xchp->i1 + xchp->chg1 <= s1 &&
+                                      xchp->i2 + xchp->chg2 <= s2)
+                                       xchp = xchp->next;
+
+                               /* If so, show it after all. */
+                               if (xchp != xch) {
+                                       xch = xchp;
+                                       goto pre_context_calculation;
+                               }
+                       }
+               }
+
+ post_context_calculation:
+               lctx = xecfg->ctxlen;
+               lctx = XDL_MIN(lctx, xe->xdf1.nrec - (xche->i1 + xche->chg1));
+               lctx = XDL_MIN(lctx, xe->xdf2.nrec - (xche->i2 + xche->chg2));
+
+               e1 = xche->i1 + xche->chg1 + lctx;
+               e2 = xche->i2 + xche->chg2 + lctx;
+
+               if (xecfg->flags & XDL_EMIT_FUNCCONTEXT) {
+                       long fe1 = get_func_line(xe, xecfg, NULL,
+                                                xche->i1 + xche->chg1,
+                                                xe->xdf1.nrec);
+                       while (fe1 > 0 && is_empty_rec(&xe->xdf1, fe1 - 1))
+                               fe1--;
+                       if (fe1 < 0)
+                               fe1 = xe->xdf1.nrec;
+                       if (fe1 > e1) {
+                               e2 = XDL_MIN(e2 + (fe1 - e1), xe->xdf2.nrec);
+                               e1 = fe1;
+                       }
+
+                       /*
+                        * Overlap with next change?  Then include it
+                        * in the current hunk and start over to find
+                        * its new end.
+                        */
+                       if (xche->next) {
+                               long l = XDL_MIN(xche->next->i1,
+                                                xe->xdf1.nrec - 1);
+                               if (l - xecfg->ctxlen <= e1 ||
+                                   get_func_line(xe, xecfg, NULL, l, e1) < 0) {
+                                       xche = xche->next;
+                                       goto post_context_calculation;
+                               }
+                       }
+               }
+
+               /*
+                * Emit current hunk header.
+                */
+
+               if (xecfg->flags & XDL_EMIT_FUNCNAMES) {
+                       get_func_line(xe, xecfg, &func_line,
+                                     s1 - 1, funclineprev);
+                       funclineprev = s1 - 1;
+               }
+               if (!(xecfg->flags & XDL_EMIT_NO_HUNK_HDR) &&
+                   xdl_emit_hunk_hdr(s1 + 1, e1 - s1, s2 + 1, e2 - s2,
+                                     func_line.buf, func_line.len, ecb) < 0)
+                       return -1;
+
+               /*
+                * Emit pre-context.
+                */
+               for (; s2 < xch->i2; s2++)
+                       if (xdl_emit_record(&xe->xdf2, s2, " ", ecb) < 0)
+                               return -1;
+
+               for (s1 = xch->i1, s2 = xch->i2;; xch = xch->next) {
+                       /*
+                        * Merge previous with current change atom.
+                        */
+                       for (; s1 < xch->i1 && s2 < xch->i2; s1++, s2++)
+                               if (xdl_emit_record(&xe->xdf2, s2, " ", ecb) < 0)
+                                       return -1;
+
+                       /*
+                        * Removes lines from the first file.
+                        */
+                       for (s1 = xch->i1; s1 < xch->i1 + xch->chg1; s1++)
+                               if (xdl_emit_record(&xe->xdf1, s1, "-", ecb) < 0)
+                                       return -1;
+
+                       /*
+                        * Adds lines from the second file.
+                        */
+                       for (s2 = xch->i2; s2 < xch->i2 + xch->chg2; s2++)
+                               if (xdl_emit_record(&xe->xdf2, s2, "+", ecb) < 0)
+                                       return -1;
+
+                       if (xch == xche)
+                               break;
+                       s1 = xch->i1 + xch->chg1;
+                       s2 = xch->i2 + xch->chg2;
+               }
+
+               /*
+                * Emit post-context.
+                */
+               for (s2 = xche->i2 + xche->chg2; s2 < e2; s2++)
+                       if (xdl_emit_record(&xe->xdf2, s2, " ", ecb) < 0)
+                               return -1;
+       }
+
+       return 0;
+}
diff --git a/xemit.h b/xemit.h
new file mode 100644 (file)
index 0000000..1b9887e
--- /dev/null
+++ b/xemit.h
@@ -0,0 +1,36 @@
+/*
+ *  LibXDiff by Davide Libenzi ( File Differential Library )
+ *  Copyright (C) 2003  Davide Libenzi
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Lesser General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 2.1 of the License, or (at your option) any later version.
+ *
+ *  This library is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public
+ *  License along with this library; if not, see
+ *  <http://www.gnu.org/licenses/>.
+ *
+ *  Davide Libenzi <davidel@xmailserver.org>
+ *
+ */
+
+#if !defined(XEMIT_H)
+#define XEMIT_H
+
+
+typedef int (*emit_func_t)(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
+                          xdemitconf_t const *xecfg);
+
+xdchange_t *xdl_get_hunk(xdchange_t **xscr, xdemitconf_t const *xecfg);
+int xdl_emit_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
+                 xdemitconf_t const *xecfg);
+
+
+
+#endif /* #if !defined(XEMIT_H) */
diff --git a/xhistogram.c b/xhistogram.c
new file mode 100644 (file)
index 0000000..16a8fe2
--- /dev/null
@@ -0,0 +1,370 @@
+/*
+ * Copyright (C) 2010, Google Inc.
+ * and other copyright owners as documented in JGit's IP log.
+ *
+ * This program and the accompanying materials are made available
+ * under the terms of the Eclipse Distribution License v1.0 which
+ * accompanies this distribution, is reproduced below, and is
+ * available at http://www.eclipse.org/org/documents/edl-v10.php
+ *
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or
+ * without modification, are permitted provided that the following
+ * conditions are met:
+ *
+ * - Redistributions of source code must retain the above copyright
+ *   notice, this list of conditions and the following disclaimer.
+ *
+ * - Redistributions in binary form must reproduce the above
+ *   copyright notice, this list of conditions and the following
+ *   disclaimer in the documentation and/or other materials provided
+ *   with the distribution.
+ *
+ * - Neither the name of the Eclipse Foundation, Inc. nor the
+ *   names of its contributors may be used to endorse or promote
+ *   products derived from this software without specific prior
+ *   written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND
+ * CONTRIBUTORS "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES,
+ * INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
+ * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
+ * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR
+ * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
+ * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
+ * LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER
+ * CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT,
+ * STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
+ * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF
+ * ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+#include "xinclude.h"
+
+#define MAX_PTR        UINT_MAX
+#define MAX_CNT        UINT_MAX
+
+#define LINE_END(n) (line##n + count##n - 1)
+#define LINE_END_PTR(n) (*line##n + *count##n - 1)
+
+struct histindex {
+       struct record {
+               unsigned int ptr, cnt;
+               struct record *next;
+       } **records, /* an occurrence */
+         **line_map; /* map of line to record chain */
+       chastore_t rcha;
+       unsigned int *next_ptrs;
+       unsigned int table_bits,
+                    records_size,
+                    line_map_size;
+
+       unsigned int max_chain_length,
+                    key_shift,
+                    ptr_shift;
+
+       unsigned int cnt,
+                    has_common;
+
+       xdfenv_t *env;
+       xpparam_t const *xpp;
+};
+
+struct region {
+       unsigned int begin1, end1;
+       unsigned int begin2, end2;
+};
+
+#define LINE_MAP(i, a) (i->line_map[(a) - i->ptr_shift])
+
+#define NEXT_PTR(index, ptr) \
+       (index->next_ptrs[(ptr) - index->ptr_shift])
+
+#define CNT(index, ptr) \
+       ((LINE_MAP(index, ptr))->cnt)
+
+#define REC(env, s, l) \
+       (env->xdf##s.recs[l - 1])
+
+static int cmp_recs(xrecord_t *r1, xrecord_t *r2)
+{
+       return r1->ha == r2->ha;
+
+}
+
+#define CMP(i, s1, l1, s2, l2) \
+       (cmp_recs(REC(i->env, s1, l1), REC(i->env, s2, l2)))
+
+#define TABLE_HASH(index, side, line) \
+       XDL_HASHLONG((REC(index->env, side, line))->ha, index->table_bits)
+
+static int scanA(struct histindex *index, int line1, int count1)
+{
+       unsigned int ptr, tbl_idx;
+       unsigned int chain_len;
+       struct record **rec_chain, *rec;
+
+       for (ptr = LINE_END(1); line1 <= ptr; ptr--) {
+               tbl_idx = TABLE_HASH(index, 1, ptr);
+               rec_chain = index->records + tbl_idx;
+               rec = *rec_chain;
+
+               chain_len = 0;
+               while (rec) {
+                       if (CMP(index, 1, rec->ptr, 1, ptr)) {
+                               /*
+                                * ptr is identical to another element. Insert
+                                * it onto the front of the existing element
+                                * chain.
+                                */
+                               NEXT_PTR(index, ptr) = rec->ptr;
+                               rec->ptr = ptr;
+                               /* cap rec->cnt at MAX_CNT */
+                               rec->cnt = XDL_MIN(MAX_CNT, rec->cnt + 1);
+                               LINE_MAP(index, ptr) = rec;
+                               goto continue_scan;
+                       }
+
+                       rec = rec->next;
+                       chain_len++;
+               }
+
+               if (chain_len == index->max_chain_length)
+                       return -1;
+
+               /*
+                * This is the first time we have ever seen this particular
+                * element in the sequence. Construct a new chain for it.
+                */
+               if (!(rec = xdl_cha_alloc(&index->rcha)))
+                       return -1;
+               rec->ptr = ptr;
+               rec->cnt = 1;
+               rec->next = *rec_chain;
+               *rec_chain = rec;
+               LINE_MAP(index, ptr) = rec;
+
+continue_scan:
+               ; /* no op */
+       }
+
+       return 0;
+}
+
+static int try_lcs(struct histindex *index, struct region *lcs, int b_ptr,
+       int line1, int count1, int line2, int count2)
+{
+       unsigned int b_next = b_ptr + 1;
+       struct record *rec = index->records[TABLE_HASH(index, 2, b_ptr)];
+       unsigned int as, ae, bs, be, np, rc;
+       int should_break;
+
+       for (; rec; rec = rec->next) {
+               if (rec->cnt > index->cnt) {
+                       if (!index->has_common)
+                               index->has_common = CMP(index, 1, rec->ptr, 2, b_ptr);
+                       continue;
+               }
+
+               as = rec->ptr;
+               if (!CMP(index, 1, as, 2, b_ptr))
+                       continue;
+
+               index->has_common = 1;
+               for (;;) {
+                       should_break = 0;
+                       np = NEXT_PTR(index, as);
+                       bs = b_ptr;
+                       ae = as;
+                       be = bs;
+                       rc = rec->cnt;
+
+                       while (line1 < as && line2 < bs
+                               && CMP(index, 1, as - 1, 2, bs - 1)) {
+                               as--;
+                               bs--;
+                               if (1 < rc)
+                                       rc = XDL_MIN(rc, CNT(index, as));
+                       }
+                       while (ae < LINE_END(1) && be < LINE_END(2)
+                               && CMP(index, 1, ae + 1, 2, be + 1)) {
+                               ae++;
+                               be++;
+                               if (1 < rc)
+                                       rc = XDL_MIN(rc, CNT(index, ae));
+                       }
+
+                       if (b_next <= be)
+                               b_next = be + 1;
+                       if (lcs->end1 - lcs->begin1 < ae - as || rc < index->cnt) {
+                               lcs->begin1 = as;
+                               lcs->begin2 = bs;
+                               lcs->end1 = ae;
+                               lcs->end2 = be;
+                               index->cnt = rc;
+                       }
+
+                       if (np == 0)
+                               break;
+
+                       while (np <= ae) {
+                               np = NEXT_PTR(index, np);
+                               if (np == 0) {
+                                       should_break = 1;
+                                       break;
+                               }
+                       }
+
+                       if (should_break)
+                               break;
+
+                       as = np;
+               }
+       }
+       return b_next;
+}
+
+static int fall_back_to_classic_diff(xpparam_t const *xpp, xdfenv_t *env,
+               int line1, int count1, int line2, int count2)
+{
+       xpparam_t xpparam;
+
+       memset(&xpparam, 0, sizeof(xpparam));
+       xpparam.flags = xpp->flags & ~XDF_DIFF_ALGORITHM_MASK;
+
+       return xdl_fall_back_diff(env, &xpparam,
+                                 line1, count1, line2, count2);
+}
+
+static inline void free_index(struct histindex *index)
+{
+       xdl_free(index->records);
+       xdl_free(index->line_map);
+       xdl_free(index->next_ptrs);
+       xdl_cha_free(&index->rcha);
+}
+
+static int find_lcs(xpparam_t const *xpp, xdfenv_t *env,
+                   struct region *lcs,
+                   int line1, int count1, int line2, int count2)
+{
+       int b_ptr;
+       int ret = -1;
+       struct histindex index;
+
+       memset(&index, 0, sizeof(index));
+
+       index.env = env;
+       index.xpp = xpp;
+
+       index.records = NULL;
+       index.line_map = NULL;
+       /* in case of early xdl_cha_free() */
+       index.rcha.head = NULL;
+
+       index.table_bits = xdl_hashbits(count1);
+       index.records_size = 1 << index.table_bits;
+       if (!XDL_CALLOC_ARRAY(index.records, index.records_size))
+               goto cleanup;
+
+       index.line_map_size = count1;
+       if (!XDL_CALLOC_ARRAY(index.line_map, index.line_map_size))
+               goto cleanup;
+
+       if (!XDL_CALLOC_ARRAY(index.next_ptrs, index.line_map_size))
+               goto cleanup;
+
+       /* lines / 4 + 1 comes from xprepare.c:xdl_prepare_ctx() */
+       if (xdl_cha_init(&index.rcha, sizeof(struct record), count1 / 4 + 1) < 0)
+               goto cleanup;
+
+       index.ptr_shift = line1;
+       index.max_chain_length = 64;
+
+       if (scanA(&index, line1, count1))
+               goto cleanup;
+
+       index.cnt = index.max_chain_length + 1;
+
+       for (b_ptr = line2; b_ptr <= LINE_END(2); )
+               b_ptr = try_lcs(&index, lcs, b_ptr, line1, count1, line2, count2);
+
+       if (index.has_common && index.max_chain_length < index.cnt)
+               ret = 1;
+       else
+               ret = 0;
+
+cleanup:
+       free_index(&index);
+       return ret;
+}
+
+static int histogram_diff(xpparam_t const *xpp, xdfenv_t *env,
+       int line1, int count1, int line2, int count2)
+{
+       struct region lcs;
+       int lcs_found;
+       int result;
+redo:
+       result = -1;
+
+       if (count1 <= 0 && count2 <= 0)
+               return 0;
+
+       if (LINE_END(1) >= MAX_PTR)
+               return -1;
+
+       if (!count1) {
+               while(count2--)
+                       env->xdf2.rchg[line2++ - 1] = 1;
+               return 0;
+       } else if (!count2) {
+               while(count1--)
+                       env->xdf1.rchg[line1++ - 1] = 1;
+               return 0;
+       }
+
+       memset(&lcs, 0, sizeof(lcs));
+       lcs_found = find_lcs(xpp, env, &lcs, line1, count1, line2, count2);
+       if (lcs_found < 0)
+               goto out;
+       else if (lcs_found)
+               result = fall_back_to_classic_diff(xpp, env, line1, count1, line2, count2);
+       else {
+               if (lcs.begin1 == 0 && lcs.begin2 == 0) {
+                       while (count1--)
+                               env->xdf1.rchg[line1++ - 1] = 1;
+                       while (count2--)
+                               env->xdf2.rchg[line2++ - 1] = 1;
+                       result = 0;
+               } else {
+                       result = histogram_diff(xpp, env,
+                                               line1, lcs.begin1 - line1,
+                                               line2, lcs.begin2 - line2);
+                       if (result)
+                               goto out;
+                       /*
+                        * result = histogram_diff(xpp, env,
+                        *            lcs.end1 + 1, LINE_END(1) - lcs.end1,
+                        *            lcs.end2 + 1, LINE_END(2) - lcs.end2);
+                        * but let's optimize tail recursion ourself:
+                       */
+                       count1 = LINE_END(1) - lcs.end1;
+                       line1 = lcs.end1 + 1;
+                       count2 = LINE_END(2) - lcs.end2;
+                       line2 = lcs.end2 + 1;
+                       goto redo;
+               }
+       }
+out:
+       return result;
+}
+
+int xdl_do_histogram_diff(xpparam_t const *xpp, xdfenv_t *env)
+{
+       return histogram_diff(xpp, env,
+               env->xdf1.dstart + 1, env->xdf1.dend - env->xdf1.dstart + 1,
+               env->xdf2.dstart + 1, env->xdf2.dend - env->xdf2.dstart + 1);
+}
diff --git a/xinclude.h b/xinclude.h
new file mode 100644 (file)
index 0000000..a4285ac
--- /dev/null
@@ -0,0 +1,36 @@
+/*
+ *  LibXDiff by Davide Libenzi ( File Differential Library )
+ *  Copyright (C) 2003  Davide Libenzi
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Lesser General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 2.1 of the License, or (at your option) any later version.
+ *
+ *  This library is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public
+ *  License along with this library; if not, see
+ *  <http://www.gnu.org/licenses/>.
+ *
+ *  Davide Libenzi <davidel@xmailserver.org>
+ *
+ */
+
+#if !defined(XINCLUDE_H)
+#define XINCLUDE_H
+
+#include "git-compat-util.h"
+#include "xmacros.h"
+#include "xdiff.h"
+#include "xtypes.h"
+#include "xutils.h"
+#include "xprepare.h"
+#include "xdiffi.h"
+#include "xemit.h"
+
+
+#endif /* #if !defined(XINCLUDE_H) */
diff --git a/xmacros.h b/xmacros.h
new file mode 100644 (file)
index 0000000..8487bb3
--- /dev/null
+++ b/xmacros.h
@@ -0,0 +1,71 @@
+/*
+ *  LibXDiff by Davide Libenzi ( File Differential Library )
+ *  Copyright (C) 2003  Davide Libenzi
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Lesser General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 2.1 of the License, or (at your option) any later version.
+ *
+ *  This library is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public
+ *  License along with this library; if not, see
+ *  <http://www.gnu.org/licenses/>.
+ *
+ *  Davide Libenzi <davidel@xmailserver.org>
+ *
+ */
+
+#if !defined(XMACROS_H)
+#define XMACROS_H
+
+
+
+
+#define XDL_MIN(a, b) ((a) < (b) ? (a): (b))
+#define XDL_MAX(a, b) ((a) > (b) ? (a): (b))
+#define XDL_ABS(v) ((v) >= 0 ? (v): -(v))
+#define XDL_ISDIGIT(c) ((c) >= '0' && (c) <= '9')
+#define XDL_ISSPACE(c) (isspace((unsigned char)(c)))
+#define XDL_ADDBITS(v,b)       ((v) + ((v) >> (b)))
+#define XDL_MASKBITS(b)                ((1UL << (b)) - 1)
+#define XDL_HASHLONG(v,b)      (XDL_ADDBITS((unsigned long)(v), b) & XDL_MASKBITS(b))
+#define XDL_LE32_PUT(p, v) \
+do { \
+       unsigned char *__p = (unsigned char *) (p); \
+       *__p++ = (unsigned char) (v); \
+       *__p++ = (unsigned char) ((v) >> 8); \
+       *__p++ = (unsigned char) ((v) >> 16); \
+       *__p = (unsigned char) ((v) >> 24); \
+} while (0)
+#define XDL_LE32_GET(p, v) \
+do { \
+       unsigned char const *__p = (unsigned char const *) (p); \
+       (v) = (unsigned long) __p[0] | ((unsigned long) __p[1]) << 8 | \
+               ((unsigned long) __p[2]) << 16 | ((unsigned long) __p[3]) << 24; \
+} while (0)
+
+/* Allocate an array of nr elements, returns NULL on failure */
+#define XDL_ALLOC_ARRAY(p, nr)                         \
+       ((p) = SIZE_MAX / sizeof(*(p)) >= (size_t)(nr)  \
+               ? xdl_malloc((nr) * sizeof(*(p)))       \
+               : NULL)
+
+/* Allocate an array of nr zeroed out elements, returns NULL on failure */
+#define XDL_CALLOC_ARRAY(p, nr)        ((p) = xdl_calloc(nr, sizeof(*(p))))
+
+/*
+ * Ensure array p can accommodate at least nr elements, growing the
+ * array and updating alloc (which is the number of allocated
+ * elements) as necessary. Frees p and returns -1 on failure, returns
+ * 0 on success
+ */
+#define XDL_ALLOC_GROW(p, nr, alloc)   \
+       (-!((nr) <= (alloc) ||          \
+           ((p) = xdl_alloc_grow_helper((p), (nr), &(alloc), sizeof(*(p))))))
+
+#endif /* #if !defined(XMACROS_H) */
diff --git a/xpatience.c b/xpatience.c
new file mode 100644 (file)
index 0000000..a2d8955
--- /dev/null
@@ -0,0 +1,373 @@
+/*
+ *  LibXDiff by Davide Libenzi ( File Differential Library )
+ *  Copyright (C) 2003-2016 Davide Libenzi, Johannes E. Schindelin
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Lesser General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 2.1 of the License, or (at your option) any later version.
+ *
+ *  This library is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public
+ *  License along with this library; if not, see
+ *  <http://www.gnu.org/licenses/>.
+ *
+ *  Davide Libenzi <davidel@xmailserver.org>
+ *
+ */
+#include "xinclude.h"
+
+/*
+ * The basic idea of patience diff is to find lines that are unique in
+ * both files.  These are intuitively the ones that we want to see as
+ * common lines.
+ *
+ * The maximal ordered sequence of such line pairs (where ordered means
+ * that the order in the sequence agrees with the order of the lines in
+ * both files) naturally defines an initial set of common lines.
+ *
+ * Now, the algorithm tries to extend the set of common lines by growing
+ * the line ranges where the files have identical lines.
+ *
+ * Between those common lines, the patience diff algorithm is applied
+ * recursively, until no unique line pairs can be found; these line ranges
+ * are handled by the well-known Myers algorithm.
+ */
+
+#define NON_UNIQUE ULONG_MAX
+
+/*
+ * This is a hash mapping from line hash to line numbers in the first and
+ * second file.
+ */
+struct hashmap {
+       int nr, alloc;
+       struct entry {
+               unsigned long hash;
+               /*
+                * 0 = unused entry, 1 = first line, 2 = second, etc.
+                * line2 is NON_UNIQUE if the line is not unique
+                * in either the first or the second file.
+                */
+               unsigned long line1, line2;
+               /*
+                * "next" & "previous" are used for the longest common
+                * sequence;
+                * initially, "next" reflects only the order in file1.
+                */
+               struct entry *next, *previous;
+
+               /*
+                * If 1, this entry can serve as an anchor. See
+                * Documentation/diff-options.txt for more information.
+                */
+               unsigned anchor : 1;
+       } *entries, *first, *last;
+       /* were common records found? */
+       unsigned long has_matches;
+       xdfenv_t *env;
+       xpparam_t const *xpp;
+};
+
+static int is_anchor(xpparam_t const *xpp, const char *line)
+{
+       int i;
+       for (i = 0; i < xpp->anchors_nr; i++) {
+               if (!strncmp(line, xpp->anchors[i], strlen(xpp->anchors[i])))
+                       return 1;
+       }
+       return 0;
+}
+
+/* The argument "pass" is 1 for the first file, 2 for the second. */
+static void insert_record(xpparam_t const *xpp, int line, struct hashmap *map,
+                         int pass)
+{
+       xrecord_t **records = pass == 1 ?
+               map->env->xdf1.recs : map->env->xdf2.recs;
+       xrecord_t *record = records[line - 1];
+       /*
+        * After xdl_prepare_env() (or more precisely, due to
+        * xdl_classify_record()), the "ha" member of the records (AKA lines)
+        * is _not_ the hash anymore, but a linearized version of it.  In
+        * other words, the "ha" member is guaranteed to start with 0 and
+        * the second record's ha can only be 0 or 1, etc.
+        *
+        * So we multiply ha by 2 in the hope that the hashing was
+        * "unique enough".
+        */
+       int index = (int)((record->ha << 1) % map->alloc);
+
+       while (map->entries[index].line1) {
+               if (map->entries[index].hash != record->ha) {
+                       if (++index >= map->alloc)
+                               index = 0;
+                       continue;
+               }
+               if (pass == 2)
+                       map->has_matches = 1;
+               if (pass == 1 || map->entries[index].line2)
+                       map->entries[index].line2 = NON_UNIQUE;
+               else
+                       map->entries[index].line2 = line;
+               return;
+       }
+       if (pass == 2)
+               return;
+       map->entries[index].line1 = line;
+       map->entries[index].hash = record->ha;
+       map->entries[index].anchor = is_anchor(xpp, map->env->xdf1.recs[line - 1]->ptr);
+       if (!map->first)
+               map->first = map->entries + index;
+       if (map->last) {
+               map->last->next = map->entries + index;
+               map->entries[index].previous = map->last;
+       }
+       map->last = map->entries + index;
+       map->nr++;
+}
+
+/*
+ * This function has to be called for each recursion into the inter-hunk
+ * parts, as previously non-unique lines can become unique when being
+ * restricted to a smaller part of the files.
+ *
+ * It is assumed that env has been prepared using xdl_prepare().
+ */
+static int fill_hashmap(xpparam_t const *xpp, xdfenv_t *env,
+               struct hashmap *result,
+               int line1, int count1, int line2, int count2)
+{
+       result->xpp = xpp;
+       result->env = env;
+
+       /* We know exactly how large we want the hash map */
+       result->alloc = count1 * 2;
+       if (!XDL_CALLOC_ARRAY(result->entries, result->alloc))
+               return -1;
+
+       /* First, fill with entries from the first file */
+       while (count1--)
+               insert_record(xpp, line1++, result, 1);
+
+       /* Then search for matches in the second file */
+       while (count2--)
+               insert_record(xpp, line2++, result, 2);
+
+       return 0;
+}
+
+/*
+ * Find the longest sequence with a smaller last element (meaning a smaller
+ * line2, as we construct the sequence with entries ordered by line1).
+ */
+static int binary_search(struct entry **sequence, int longest,
+               struct entry *entry)
+{
+       int left = -1, right = longest;
+
+       while (left + 1 < right) {
+               int middle = left + (right - left) / 2;
+               /* by construction, no two entries can be equal */
+               if (sequence[middle]->line2 > entry->line2)
+                       right = middle;
+               else
+                       left = middle;
+       }
+       /* return the index in "sequence", _not_ the sequence length */
+       return left;
+}
+
+/*
+ * The idea is to start with the list of common unique lines sorted by
+ * the order in file1.  For each of these pairs, the longest (partial)
+ * sequence whose last element's line2 is smaller is determined.
+ *
+ * For efficiency, the sequences are kept in a list containing exactly one
+ * item per sequence length: the sequence with the smallest last
+ * element (in terms of line2).
+ */
+static int find_longest_common_sequence(struct hashmap *map, struct entry **res)
+{
+       struct entry **sequence;
+       int longest = 0, i;
+       struct entry *entry;
+
+       /*
+        * If not -1, this entry in sequence must never be overridden.
+        * Therefore, overriding entries before this has no effect, so
+        * do not do that either.
+        */
+       int anchor_i = -1;
+
+       if (!XDL_ALLOC_ARRAY(sequence, map->nr))
+               return -1;
+
+       for (entry = map->first; entry; entry = entry->next) {
+               if (!entry->line2 || entry->line2 == NON_UNIQUE)
+                       continue;
+               i = binary_search(sequence, longest, entry);
+               entry->previous = i < 0 ? NULL : sequence[i];
+               ++i;
+               if (i <= anchor_i)
+                       continue;
+               sequence[i] = entry;
+               if (entry->anchor) {
+                       anchor_i = i;
+                       longest = anchor_i + 1;
+               } else if (i == longest) {
+                       longest++;
+               }
+       }
+
+       /* No common unique lines were found */
+       if (!longest) {
+               *res = NULL;
+               xdl_free(sequence);
+               return 0;
+       }
+
+       /* Iterate starting at the last element, adjusting the "next" members */
+       entry = sequence[longest - 1];
+       entry->next = NULL;
+       while (entry->previous) {
+               entry->previous->next = entry;
+               entry = entry->previous;
+       }
+       *res = entry;
+       xdl_free(sequence);
+       return 0;
+}
+
+static int match(struct hashmap *map, int line1, int line2)
+{
+       xrecord_t *record1 = map->env->xdf1.recs[line1 - 1];
+       xrecord_t *record2 = map->env->xdf2.recs[line2 - 1];
+       return record1->ha == record2->ha;
+}
+
+static int patience_diff(xpparam_t const *xpp, xdfenv_t *env,
+               int line1, int count1, int line2, int count2);
+
+static int walk_common_sequence(struct hashmap *map, struct entry *first,
+               int line1, int count1, int line2, int count2)
+{
+       int end1 = line1 + count1, end2 = line2 + count2;
+       int next1, next2;
+
+       for (;;) {
+               /* Try to grow the line ranges of common lines */
+               if (first) {
+                       next1 = first->line1;
+                       next2 = first->line2;
+                       while (next1 > line1 && next2 > line2 &&
+                                       match(map, next1 - 1, next2 - 1)) {
+                               next1--;
+                               next2--;
+                       }
+               } else {
+                       next1 = end1;
+                       next2 = end2;
+               }
+               while (line1 < next1 && line2 < next2 &&
+                               match(map, line1, line2)) {
+                       line1++;
+                       line2++;
+               }
+
+               /* Recurse */
+               if (next1 > line1 || next2 > line2) {
+                       if (patience_diff(map->xpp, map->env,
+                                       line1, next1 - line1,
+                                       line2, next2 - line2))
+                               return -1;
+               }
+
+               if (!first)
+                       return 0;
+
+               while (first->next &&
+                               first->next->line1 == first->line1 + 1 &&
+                               first->next->line2 == first->line2 + 1)
+                       first = first->next;
+
+               line1 = first->line1 + 1;
+               line2 = first->line2 + 1;
+
+               first = first->next;
+       }
+}
+
+static int fall_back_to_classic_diff(struct hashmap *map,
+               int line1, int count1, int line2, int count2)
+{
+       xpparam_t xpp;
+
+       memset(&xpp, 0, sizeof(xpp));
+       xpp.flags = map->xpp->flags & ~XDF_DIFF_ALGORITHM_MASK;
+
+       return xdl_fall_back_diff(map->env, &xpp,
+                                 line1, count1, line2, count2);
+}
+
+/*
+ * Recursively find the longest common sequence of unique lines,
+ * and if none was found, ask xdl_do_diff() to do the job.
+ *
+ * This function assumes that env was prepared with xdl_prepare_env().
+ */
+static int patience_diff(xpparam_t const *xpp, xdfenv_t *env,
+               int line1, int count1, int line2, int count2)
+{
+       struct hashmap map;
+       struct entry *first;
+       int result = 0;
+
+       /* trivial case: one side is empty */
+       if (!count1) {
+               while(count2--)
+                       env->xdf2.rchg[line2++ - 1] = 1;
+               return 0;
+       } else if (!count2) {
+               while(count1--)
+                       env->xdf1.rchg[line1++ - 1] = 1;
+               return 0;
+       }
+
+       memset(&map, 0, sizeof(map));
+       if (fill_hashmap(xpp, env, &map,
+                       line1, count1, line2, count2))
+               return -1;
+
+       /* are there any matching lines at all? */
+       if (!map.has_matches) {
+               while(count1--)
+                       env->xdf1.rchg[line1++ - 1] = 1;
+               while(count2--)
+                       env->xdf2.rchg[line2++ - 1] = 1;
+               xdl_free(map.entries);
+               return 0;
+       }
+
+       result = find_longest_common_sequence(&map, &first);
+       if (result)
+               goto out;
+       if (first)
+               result = walk_common_sequence(&map, first,
+                       line1, count1, line2, count2);
+       else
+               result = fall_back_to_classic_diff(&map,
+                       line1, count1, line2, count2);
+ out:
+       xdl_free(map.entries);
+       return result;
+}
+
+int xdl_do_patience_diff(xpparam_t const *xpp, xdfenv_t *env)
+{
+       return patience_diff(xpp, env, 1, env->xdf1.nrec, 1, env->xdf2.nrec);
+}
diff --git a/xprepare.c b/xprepare.c
new file mode 100644 (file)
index 0000000..c84549f
--- /dev/null
@@ -0,0 +1,461 @@
+/*
+ *  LibXDiff by Davide Libenzi ( File Differential Library )
+ *  Copyright (C) 2003  Davide Libenzi
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Lesser General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 2.1 of the License, or (at your option) any later version.
+ *
+ *  This library is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public
+ *  License along with this library; if not, see
+ *  <http://www.gnu.org/licenses/>.
+ *
+ *  Davide Libenzi <davidel@xmailserver.org>
+ *
+ */
+
+#include "xinclude.h"
+
+
+#define XDL_KPDIS_RUN 4
+#define XDL_MAX_EQLIMIT 1024
+#define XDL_SIMSCAN_WINDOW 100
+#define XDL_GUESS_NLINES1 256
+#define XDL_GUESS_NLINES2 20
+
+
+typedef struct s_xdlclass {
+       struct s_xdlclass *next;
+       unsigned long ha;
+       char const *line;
+       long size;
+       long idx;
+       long len1, len2;
+} xdlclass_t;
+
+typedef struct s_xdlclassifier {
+       unsigned int hbits;
+       long hsize;
+       xdlclass_t **rchash;
+       chastore_t ncha;
+       xdlclass_t **rcrecs;
+       long alloc;
+       long count;
+       long flags;
+} xdlclassifier_t;
+
+
+
+
+static int xdl_init_classifier(xdlclassifier_t *cf, long size, long flags);
+static void xdl_free_classifier(xdlclassifier_t *cf);
+static int xdl_classify_record(unsigned int pass, xdlclassifier_t *cf, xrecord_t **rhash,
+                              unsigned int hbits, xrecord_t *rec);
+static int xdl_prepare_ctx(unsigned int pass, mmfile_t *mf, long narec, xpparam_t const *xpp,
+                          xdlclassifier_t *cf, xdfile_t *xdf);
+static void xdl_free_ctx(xdfile_t *xdf);
+static int xdl_clean_mmatch(char const *dis, long i, long s, long e);
+static int xdl_cleanup_records(xdlclassifier_t *cf, xdfile_t *xdf1, xdfile_t *xdf2);
+static int xdl_trim_ends(xdfile_t *xdf1, xdfile_t *xdf2);
+static int xdl_optimize_ctxs(xdlclassifier_t *cf, xdfile_t *xdf1, xdfile_t *xdf2);
+
+
+
+
+static int xdl_init_classifier(xdlclassifier_t *cf, long size, long flags) {
+       cf->flags = flags;
+
+       cf->hbits = xdl_hashbits((unsigned int) size);
+       cf->hsize = 1 << cf->hbits;
+
+       if (xdl_cha_init(&cf->ncha, sizeof(xdlclass_t), size / 4 + 1) < 0) {
+
+               return -1;
+       }
+       if (!XDL_CALLOC_ARRAY(cf->rchash, cf->hsize)) {
+
+               xdl_cha_free(&cf->ncha);
+               return -1;
+       }
+
+       cf->alloc = size;
+       if (!XDL_ALLOC_ARRAY(cf->rcrecs, cf->alloc)) {
+
+               xdl_free(cf->rchash);
+               xdl_cha_free(&cf->ncha);
+               return -1;
+       }
+
+       cf->count = 0;
+
+       return 0;
+}
+
+
+static void xdl_free_classifier(xdlclassifier_t *cf) {
+
+       xdl_free(cf->rcrecs);
+       xdl_free(cf->rchash);
+       xdl_cha_free(&cf->ncha);
+}
+
+
+static int xdl_classify_record(unsigned int pass, xdlclassifier_t *cf, xrecord_t **rhash,
+                              unsigned int hbits, xrecord_t *rec) {
+       long hi;
+       char const *line;
+       xdlclass_t *rcrec;
+
+       line = rec->ptr;
+       hi = (long) XDL_HASHLONG(rec->ha, cf->hbits);
+       for (rcrec = cf->rchash[hi]; rcrec; rcrec = rcrec->next)
+               if (rcrec->ha == rec->ha &&
+                               xdl_recmatch(rcrec->line, rcrec->size,
+                                       rec->ptr, rec->size, cf->flags))
+                       break;
+
+       if (!rcrec) {
+               if (!(rcrec = xdl_cha_alloc(&cf->ncha))) {
+
+                       return -1;
+               }
+               rcrec->idx = cf->count++;
+               if (XDL_ALLOC_GROW(cf->rcrecs, cf->count, cf->alloc))
+                               return -1;
+               cf->rcrecs[rcrec->idx] = rcrec;
+               rcrec->line = line;
+               rcrec->size = rec->size;
+               rcrec->ha = rec->ha;
+               rcrec->len1 = rcrec->len2 = 0;
+               rcrec->next = cf->rchash[hi];
+               cf->rchash[hi] = rcrec;
+       }
+
+       (pass == 1) ? rcrec->len1++ : rcrec->len2++;
+
+       rec->ha = (unsigned long) rcrec->idx;
+
+       hi = (long) XDL_HASHLONG(rec->ha, hbits);
+       rec->next = rhash[hi];
+       rhash[hi] = rec;
+
+       return 0;
+}
+
+
+static int xdl_prepare_ctx(unsigned int pass, mmfile_t *mf, long narec, xpparam_t const *xpp,
+                          xdlclassifier_t *cf, xdfile_t *xdf) {
+       unsigned int hbits;
+       long nrec, hsize, bsize;
+       unsigned long hav;
+       char const *blk, *cur, *top, *prev;
+       xrecord_t *crec;
+       xrecord_t **recs;
+       xrecord_t **rhash;
+       unsigned long *ha;
+       char *rchg;
+       long *rindex;
+
+       ha = NULL;
+       rindex = NULL;
+       rchg = NULL;
+       rhash = NULL;
+       recs = NULL;
+
+       if (xdl_cha_init(&xdf->rcha, sizeof(xrecord_t), narec / 4 + 1) < 0)
+               goto abort;
+       if (!XDL_ALLOC_ARRAY(recs, narec))
+               goto abort;
+
+       hbits = xdl_hashbits((unsigned int) narec);
+       hsize = 1 << hbits;
+       if (!XDL_CALLOC_ARRAY(rhash, hsize))
+               goto abort;
+
+       nrec = 0;
+       if ((cur = blk = xdl_mmfile_first(mf, &bsize))) {
+               for (top = blk + bsize; cur < top; ) {
+                       prev = cur;
+                       hav = xdl_hash_record(&cur, top, xpp->flags);
+                       if (XDL_ALLOC_GROW(recs, nrec + 1, narec))
+                               goto abort;
+                       if (!(crec = xdl_cha_alloc(&xdf->rcha)))
+                               goto abort;
+                       crec->ptr = prev;
+                       crec->size = (long) (cur - prev);
+                       crec->ha = hav;
+                       recs[nrec++] = crec;
+                       if (xdl_classify_record(pass, cf, rhash, hbits, crec) < 0)
+                               goto abort;
+               }
+       }
+
+       if (!XDL_CALLOC_ARRAY(rchg, nrec + 2))
+               goto abort;
+
+       if ((XDF_DIFF_ALG(xpp->flags) != XDF_PATIENCE_DIFF) &&
+           (XDF_DIFF_ALG(xpp->flags) != XDF_HISTOGRAM_DIFF)) {
+               if (!XDL_ALLOC_ARRAY(rindex, nrec + 1))
+                       goto abort;
+               if (!XDL_ALLOC_ARRAY(ha, nrec + 1))
+                       goto abort;
+       }
+
+       xdf->nrec = nrec;
+       xdf->recs = recs;
+       xdf->hbits = hbits;
+       xdf->rhash = rhash;
+       xdf->rchg = rchg + 1;
+       xdf->rindex = rindex;
+       xdf->nreff = 0;
+       xdf->ha = ha;
+       xdf->dstart = 0;
+       xdf->dend = nrec - 1;
+
+       return 0;
+
+abort:
+       xdl_free(ha);
+       xdl_free(rindex);
+       xdl_free(rchg);
+       xdl_free(rhash);
+       xdl_free(recs);
+       xdl_cha_free(&xdf->rcha);
+       return -1;
+}
+
+
+static void xdl_free_ctx(xdfile_t *xdf) {
+
+       xdl_free(xdf->rhash);
+       xdl_free(xdf->rindex);
+       xdl_free(xdf->rchg - 1);
+       xdl_free(xdf->ha);
+       xdl_free(xdf->recs);
+       xdl_cha_free(&xdf->rcha);
+}
+
+
+int xdl_prepare_env(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp,
+                   xdfenv_t *xe) {
+       long enl1, enl2, sample;
+       xdlclassifier_t cf;
+
+       memset(&cf, 0, sizeof(cf));
+
+       /*
+        * For histogram diff, we can afford a smaller sample size and
+        * thus a poorer estimate of the number of lines, as the hash
+        * table (rhash) won't be filled up/grown. The number of lines
+        * (nrecs) will be updated correctly anyway by
+        * xdl_prepare_ctx().
+        */
+       sample = (XDF_DIFF_ALG(xpp->flags) == XDF_HISTOGRAM_DIFF
+                 ? XDL_GUESS_NLINES2 : XDL_GUESS_NLINES1);
+
+       enl1 = xdl_guess_lines(mf1, sample) + 1;
+       enl2 = xdl_guess_lines(mf2, sample) + 1;
+
+       if (xdl_init_classifier(&cf, enl1 + enl2 + 1, xpp->flags) < 0)
+               return -1;
+
+       if (xdl_prepare_ctx(1, mf1, enl1, xpp, &cf, &xe->xdf1) < 0) {
+
+               xdl_free_classifier(&cf);
+               return -1;
+       }
+       if (xdl_prepare_ctx(2, mf2, enl2, xpp, &cf, &xe->xdf2) < 0) {
+
+               xdl_free_ctx(&xe->xdf1);
+               xdl_free_classifier(&cf);
+               return -1;
+       }
+
+       if ((XDF_DIFF_ALG(xpp->flags) != XDF_PATIENCE_DIFF) &&
+           (XDF_DIFF_ALG(xpp->flags) != XDF_HISTOGRAM_DIFF) &&
+           xdl_optimize_ctxs(&cf, &xe->xdf1, &xe->xdf2) < 0) {
+
+               xdl_free_ctx(&xe->xdf2);
+               xdl_free_ctx(&xe->xdf1);
+               xdl_free_classifier(&cf);
+               return -1;
+       }
+
+       xdl_free_classifier(&cf);
+
+       return 0;
+}
+
+
+void xdl_free_env(xdfenv_t *xe) {
+
+       xdl_free_ctx(&xe->xdf2);
+       xdl_free_ctx(&xe->xdf1);
+}
+
+
+static int xdl_clean_mmatch(char const *dis, long i, long s, long e) {
+       long r, rdis0, rpdis0, rdis1, rpdis1;
+
+       /*
+        * Limits the window the is examined during the similar-lines
+        * scan. The loops below stops when dis[i - r] == 1 (line that
+        * has no match), but there are corner cases where the loop
+        * proceed all the way to the extremities by causing huge
+        * performance penalties in case of big files.
+        */
+       if (i - s > XDL_SIMSCAN_WINDOW)
+               s = i - XDL_SIMSCAN_WINDOW;
+       if (e - i > XDL_SIMSCAN_WINDOW)
+               e = i + XDL_SIMSCAN_WINDOW;
+
+       /*
+        * Scans the lines before 'i' to find a run of lines that either
+        * have no match (dis[j] == 0) or have multiple matches (dis[j] > 1).
+        * Note that we always call this function with dis[i] > 1, so the
+        * current line (i) is already a multimatch line.
+        */
+       for (r = 1, rdis0 = 0, rpdis0 = 1; (i - r) >= s; r++) {
+               if (!dis[i - r])
+                       rdis0++;
+               else if (dis[i - r] == 2)
+                       rpdis0++;
+               else
+                       break;
+       }
+       /*
+        * If the run before the line 'i' found only multimatch lines, we
+        * return 0 and hence we don't make the current line (i) discarded.
+        * We want to discard multimatch lines only when they appear in the
+        * middle of runs with nomatch lines (dis[j] == 0).
+        */
+       if (rdis0 == 0)
+               return 0;
+       for (r = 1, rdis1 = 0, rpdis1 = 1; (i + r) <= e; r++) {
+               if (!dis[i + r])
+                       rdis1++;
+               else if (dis[i + r] == 2)
+                       rpdis1++;
+               else
+                       break;
+       }
+       /*
+        * If the run after the line 'i' found only multimatch lines, we
+        * return 0 and hence we don't make the current line (i) discarded.
+        */
+       if (rdis1 == 0)
+               return 0;
+       rdis1 += rdis0;
+       rpdis1 += rpdis0;
+
+       return rpdis1 * XDL_KPDIS_RUN < (rpdis1 + rdis1);
+}
+
+
+/*
+ * Try to reduce the problem complexity, discard records that have no
+ * matches on the other file. Also, lines that have multiple matches
+ * might be potentially discarded if they happear in a run of discardable.
+ */
+static int xdl_cleanup_records(xdlclassifier_t *cf, xdfile_t *xdf1, xdfile_t *xdf2) {
+       long i, nm, nreff, mlim;
+       xrecord_t **recs;
+       xdlclass_t *rcrec;
+       char *dis, *dis1, *dis2;
+
+       if (!XDL_CALLOC_ARRAY(dis, xdf1->nrec + xdf2->nrec + 2))
+               return -1;
+       dis1 = dis;
+       dis2 = dis1 + xdf1->nrec + 1;
+
+       if ((mlim = xdl_bogosqrt(xdf1->nrec)) > XDL_MAX_EQLIMIT)
+               mlim = XDL_MAX_EQLIMIT;
+       for (i = xdf1->dstart, recs = &xdf1->recs[xdf1->dstart]; i <= xdf1->dend; i++, recs++) {
+               rcrec = cf->rcrecs[(*recs)->ha];
+               nm = rcrec ? rcrec->len2 : 0;
+               dis1[i] = (nm == 0) ? 0: (nm >= mlim) ? 2: 1;
+       }
+
+       if ((mlim = xdl_bogosqrt(xdf2->nrec)) > XDL_MAX_EQLIMIT)
+               mlim = XDL_MAX_EQLIMIT;
+       for (i = xdf2->dstart, recs = &xdf2->recs[xdf2->dstart]; i <= xdf2->dend; i++, recs++) {
+               rcrec = cf->rcrecs[(*recs)->ha];
+               nm = rcrec ? rcrec->len1 : 0;
+               dis2[i] = (nm == 0) ? 0: (nm >= mlim) ? 2: 1;
+       }
+
+       for (nreff = 0, i = xdf1->dstart, recs = &xdf1->recs[xdf1->dstart];
+            i <= xdf1->dend; i++, recs++) {
+               if (dis1[i] == 1 ||
+                   (dis1[i] == 2 && !xdl_clean_mmatch(dis1, i, xdf1->dstart, xdf1->dend))) {
+                       xdf1->rindex[nreff] = i;
+                       xdf1->ha[nreff] = (*recs)->ha;
+                       nreff++;
+               } else
+                       xdf1->rchg[i] = 1;
+       }
+       xdf1->nreff = nreff;
+
+       for (nreff = 0, i = xdf2->dstart, recs = &xdf2->recs[xdf2->dstart];
+            i <= xdf2->dend; i++, recs++) {
+               if (dis2[i] == 1 ||
+                   (dis2[i] == 2 && !xdl_clean_mmatch(dis2, i, xdf2->dstart, xdf2->dend))) {
+                       xdf2->rindex[nreff] = i;
+                       xdf2->ha[nreff] = (*recs)->ha;
+                       nreff++;
+               } else
+                       xdf2->rchg[i] = 1;
+       }
+       xdf2->nreff = nreff;
+
+       xdl_free(dis);
+
+       return 0;
+}
+
+
+/*
+ * Early trim initial and terminal matching records.
+ */
+static int xdl_trim_ends(xdfile_t *xdf1, xdfile_t *xdf2) {
+       long i, lim;
+       xrecord_t **recs1, **recs2;
+
+       recs1 = xdf1->recs;
+       recs2 = xdf2->recs;
+       for (i = 0, lim = XDL_MIN(xdf1->nrec, xdf2->nrec); i < lim;
+            i++, recs1++, recs2++)
+               if ((*recs1)->ha != (*recs2)->ha)
+                       break;
+
+       xdf1->dstart = xdf2->dstart = i;
+
+       recs1 = xdf1->recs + xdf1->nrec - 1;
+       recs2 = xdf2->recs + xdf2->nrec - 1;
+       for (lim -= i, i = 0; i < lim; i++, recs1--, recs2--)
+               if ((*recs1)->ha != (*recs2)->ha)
+                       break;
+
+       xdf1->dend = xdf1->nrec - i - 1;
+       xdf2->dend = xdf2->nrec - i - 1;
+
+       return 0;
+}
+
+
+static int xdl_optimize_ctxs(xdlclassifier_t *cf, xdfile_t *xdf1, xdfile_t *xdf2) {
+
+       if (xdl_trim_ends(xdf1, xdf2) < 0 ||
+           xdl_cleanup_records(cf, xdf1, xdf2) < 0) {
+
+               return -1;
+       }
+
+       return 0;
+}
diff --git a/xprepare.h b/xprepare.h
new file mode 100644 (file)
index 0000000..947d9fc
--- /dev/null
@@ -0,0 +1,34 @@
+/*
+ *  LibXDiff by Davide Libenzi ( File Differential Library )
+ *  Copyright (C) 2003  Davide Libenzi
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Lesser General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 2.1 of the License, or (at your option) any later version.
+ *
+ *  This library is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public
+ *  License along with this library; if not, see
+ *  <http://www.gnu.org/licenses/>.
+ *
+ *  Davide Libenzi <davidel@xmailserver.org>
+ *
+ */
+
+#if !defined(XPREPARE_H)
+#define XPREPARE_H
+
+
+
+int xdl_prepare_env(mmfile_t *mf1, mmfile_t *mf2, xpparam_t const *xpp,
+                   xdfenv_t *xe);
+void xdl_free_env(xdfenv_t *xe);
+
+
+
+#endif /* #if !defined(XPREPARE_H) */
diff --git a/xtypes.h b/xtypes.h
new file mode 100644 (file)
index 0000000..8442bd4
--- /dev/null
+++ b/xtypes.h
@@ -0,0 +1,67 @@
+/*
+ *  LibXDiff by Davide Libenzi ( File Differential Library )
+ *  Copyright (C) 2003  Davide Libenzi
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Lesser General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 2.1 of the License, or (at your option) any later version.
+ *
+ *  This library is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public
+ *  License along with this library; if not, see
+ *  <http://www.gnu.org/licenses/>.
+ *
+ *  Davide Libenzi <davidel@xmailserver.org>
+ *
+ */
+
+#if !defined(XTYPES_H)
+#define XTYPES_H
+
+
+
+typedef struct s_chanode {
+       struct s_chanode *next;
+       long icurr;
+} chanode_t;
+
+typedef struct s_chastore {
+       chanode_t *head, *tail;
+       long isize, nsize;
+       chanode_t *ancur;
+       chanode_t *sncur;
+       long scurr;
+} chastore_t;
+
+typedef struct s_xrecord {
+       struct s_xrecord *next;
+       char const *ptr;
+       long size;
+       unsigned long ha;
+} xrecord_t;
+
+typedef struct s_xdfile {
+       chastore_t rcha;
+       long nrec;
+       unsigned int hbits;
+       xrecord_t **rhash;
+       long dstart, dend;
+       xrecord_t **recs;
+       char *rchg;
+       long *rindex;
+       long nreff;
+       unsigned long *ha;
+} xdfile_t;
+
+typedef struct s_xdfenv {
+       xdfile_t xdf1, xdf2;
+} xdfenv_t;
+
+
+
+#endif /* #if !defined(XTYPES_H) */
diff --git a/xutils.c b/xutils.c
new file mode 100644 (file)
index 0000000..9e36f24
--- /dev/null
+++ b/xutils.c
@@ -0,0 +1,451 @@
+/*
+ *  LibXDiff by Davide Libenzi ( File Differential Library )
+ *  Copyright (C) 2003 Davide Libenzi
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Lesser General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 2.1 of the License, or (at your option) any later version.
+ *
+ *  This library is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public
+ *  License along with this library; if not, see
+ *  <http://www.gnu.org/licenses/>.
+ *
+ *  Davide Libenzi <davidel@xmailserver.org>
+ *
+ */
+
+#include "xinclude.h"
+
+
+long xdl_bogosqrt(long n) {
+       long i;
+
+       /*
+        * Classical integer square root approximation using shifts.
+        */
+       for (i = 1; n > 0; n >>= 2)
+               i <<= 1;
+
+       return i;
+}
+
+
+int xdl_emit_diffrec(char const *rec, long size, char const *pre, long psize,
+                    xdemitcb_t *ecb) {
+       int i = 2;
+       mmbuffer_t mb[3];
+
+       mb[0].ptr = (char *) pre;
+       mb[0].size = psize;
+       mb[1].ptr = (char *) rec;
+       mb[1].size = size;
+       if (size > 0 && rec[size - 1] != '\n') {
+               mb[2].ptr = (char *) "\n\\ No newline at end of file\n";
+               mb[2].size = strlen(mb[2].ptr);
+               i++;
+       }
+       if (ecb->out_line(ecb->priv, mb, i) < 0) {
+
+               return -1;
+       }
+
+       return 0;
+}
+
+void *xdl_mmfile_first(mmfile_t *mmf, long *size)
+{
+       *size = mmf->size;
+       return mmf->ptr;
+}
+
+
+long xdl_mmfile_size(mmfile_t *mmf)
+{
+       return mmf->size;
+}
+
+
+int xdl_cha_init(chastore_t *cha, long isize, long icount) {
+
+       cha->head = cha->tail = NULL;
+       cha->isize = isize;
+       cha->nsize = icount * isize;
+       cha->ancur = cha->sncur = NULL;
+       cha->scurr = 0;
+
+       return 0;
+}
+
+
+void xdl_cha_free(chastore_t *cha) {
+       chanode_t *cur, *tmp;
+
+       for (cur = cha->head; (tmp = cur) != NULL;) {
+               cur = cur->next;
+               xdl_free(tmp);
+       }
+}
+
+
+void *xdl_cha_alloc(chastore_t *cha) {
+       chanode_t *ancur;
+       void *data;
+
+       if (!(ancur = cha->ancur) || ancur->icurr == cha->nsize) {
+               if (!(ancur = (chanode_t *) xdl_malloc(sizeof(chanode_t) + cha->nsize))) {
+
+                       return NULL;
+               }
+               ancur->icurr = 0;
+               ancur->next = NULL;
+               if (cha->tail)
+                       cha->tail->next = ancur;
+               if (!cha->head)
+                       cha->head = ancur;
+               cha->tail = ancur;
+               cha->ancur = ancur;
+       }
+
+       data = (char *) ancur + sizeof(chanode_t) + ancur->icurr;
+       ancur->icurr += cha->isize;
+
+       return data;
+}
+
+long xdl_guess_lines(mmfile_t *mf, long sample) {
+       long nl = 0, size, tsize = 0;
+       char const *data, *cur, *top;
+
+       if ((cur = data = xdl_mmfile_first(mf, &size))) {
+               for (top = data + size; nl < sample && cur < top; ) {
+                       nl++;
+                       if (!(cur = memchr(cur, '\n', top - cur)))
+                               cur = top;
+                       else
+                               cur++;
+               }
+               tsize += (long) (cur - data);
+       }
+
+       if (nl && tsize)
+               nl = xdl_mmfile_size(mf) / (tsize / nl);
+
+       return nl + 1;
+}
+
+int xdl_blankline(const char *line, long size, long flags)
+{
+       long i;
+
+       if (!(flags & XDF_WHITESPACE_FLAGS))
+               return (size <= 1);
+
+       for (i = 0; i < size && XDL_ISSPACE(line[i]); i++)
+               ;
+
+       return (i == size);
+}
+
+/*
+ * Have we eaten everything on the line, except for an optional
+ * CR at the very end?
+ */
+static int ends_with_optional_cr(const char *l, long s, long i)
+{
+       int complete = s && l[s-1] == '\n';
+
+       if (complete)
+               s--;
+       if (s == i)
+               return 1;
+       /* do not ignore CR at the end of an incomplete line */
+       if (complete && s == i + 1 && l[i] == '\r')
+               return 1;
+       return 0;
+}
+
+int xdl_recmatch(const char *l1, long s1, const char *l2, long s2, long flags)
+{
+       int i1, i2;
+
+       if (s1 == s2 && !memcmp(l1, l2, s1))
+               return 1;
+       if (!(flags & XDF_WHITESPACE_FLAGS))
+               return 0;
+
+       i1 = 0;
+       i2 = 0;
+
+       /*
+        * -w matches everything that matches with -b, and -b in turn
+        * matches everything that matches with --ignore-space-at-eol,
+        * which in turn matches everything that matches with --ignore-cr-at-eol.
+        *
+        * Each flavor of ignoring needs different logic to skip whitespaces
+        * while we have both sides to compare.
+        */
+       if (flags & XDF_IGNORE_WHITESPACE) {
+               goto skip_ws;
+               while (i1 < s1 && i2 < s2) {
+                       if (l1[i1++] != l2[i2++])
+                               return 0;
+               skip_ws:
+                       while (i1 < s1 && XDL_ISSPACE(l1[i1]))
+                               i1++;
+                       while (i2 < s2 && XDL_ISSPACE(l2[i2]))
+                               i2++;
+               }
+       } else if (flags & XDF_IGNORE_WHITESPACE_CHANGE) {
+               while (i1 < s1 && i2 < s2) {
+                       if (XDL_ISSPACE(l1[i1]) && XDL_ISSPACE(l2[i2])) {
+                               /* Skip matching spaces and try again */
+                               while (i1 < s1 && XDL_ISSPACE(l1[i1]))
+                                       i1++;
+                               while (i2 < s2 && XDL_ISSPACE(l2[i2]))
+                                       i2++;
+                               continue;
+                       }
+                       if (l1[i1++] != l2[i2++])
+                               return 0;
+               }
+       } else if (flags & XDF_IGNORE_WHITESPACE_AT_EOL) {
+               while (i1 < s1 && i2 < s2 && l1[i1] == l2[i2]) {
+                       i1++;
+                       i2++;
+               }
+       } else if (flags & XDF_IGNORE_CR_AT_EOL) {
+               /* Find the first difference and see how the line ends */
+               while (i1 < s1 && i2 < s2 && l1[i1] == l2[i2]) {
+                       i1++;
+                       i2++;
+               }
+               return (ends_with_optional_cr(l1, s1, i1) &&
+                       ends_with_optional_cr(l2, s2, i2));
+       }
+
+       /*
+        * After running out of one side, the remaining side must have
+        * nothing but whitespace for the lines to match.  Note that
+        * ignore-whitespace-at-eol case may break out of the loop
+        * while there still are characters remaining on both lines.
+        */
+       if (i1 < s1) {
+               while (i1 < s1 && XDL_ISSPACE(l1[i1]))
+                       i1++;
+               if (s1 != i1)
+                       return 0;
+       }
+       if (i2 < s2) {
+               while (i2 < s2 && XDL_ISSPACE(l2[i2]))
+                       i2++;
+               return (s2 == i2);
+       }
+       return 1;
+}
+
+static unsigned long xdl_hash_record_with_whitespace(char const **data,
+               char const *top, long flags) {
+       unsigned long ha = 5381;
+       char const *ptr = *data;
+       int cr_at_eol_only = (flags & XDF_WHITESPACE_FLAGS) == XDF_IGNORE_CR_AT_EOL;
+
+       for (; ptr < top && *ptr != '\n'; ptr++) {
+               if (cr_at_eol_only) {
+                       /* do not ignore CR at the end of an incomplete line */
+                       if (*ptr == '\r' &&
+                           (ptr + 1 < top && ptr[1] == '\n'))
+                               continue;
+               }
+               else if (XDL_ISSPACE(*ptr)) {
+                       const char *ptr2 = ptr;
+                       int at_eol;
+                       while (ptr + 1 < top && XDL_ISSPACE(ptr[1])
+                                       && ptr[1] != '\n')
+                               ptr++;
+                       at_eol = (top <= ptr + 1 || ptr[1] == '\n');
+                       if (flags & XDF_IGNORE_WHITESPACE)
+                               ; /* already handled */
+                       else if (flags & XDF_IGNORE_WHITESPACE_CHANGE
+                                && !at_eol) {
+                               ha += (ha << 5);
+                               ha ^= (unsigned long) ' ';
+                       }
+                       else if (flags & XDF_IGNORE_WHITESPACE_AT_EOL
+                                && !at_eol) {
+                               while (ptr2 != ptr + 1) {
+                                       ha += (ha << 5);
+                                       ha ^= (unsigned long) *ptr2;
+                                       ptr2++;
+                               }
+                       }
+                       continue;
+               }
+               ha += (ha << 5);
+               ha ^= (unsigned long) *ptr;
+       }
+       *data = ptr < top ? ptr + 1: ptr;
+
+       return ha;
+}
+
+unsigned long xdl_hash_record(char const **data, char const *top, long flags) {
+       unsigned long ha = 5381;
+       char const *ptr = *data;
+
+       if (flags & XDF_WHITESPACE_FLAGS)
+               return xdl_hash_record_with_whitespace(data, top, flags);
+
+       for (; ptr < top && *ptr != '\n'; ptr++) {
+               ha += (ha << 5);
+               ha ^= (unsigned long) *ptr;
+       }
+       *data = ptr < top ? ptr + 1: ptr;
+
+       return ha;
+}
+
+unsigned int xdl_hashbits(unsigned int size) {
+       unsigned int val = 1, bits = 0;
+
+       for (; val < size && bits < CHAR_BIT * sizeof(unsigned int); val <<= 1, bits++);
+       return bits ? bits: 1;
+}
+
+
+int xdl_num_out(char *out, long val) {
+       char *ptr, *str = out;
+       char buf[32];
+
+       ptr = buf + sizeof(buf) - 1;
+       *ptr = '\0';
+       if (val < 0) {
+               *--ptr = '-';
+               val = -val;
+       }
+       for (; val && ptr > buf; val /= 10)
+               *--ptr = "0123456789"[val % 10];
+       if (*ptr)
+               for (; *ptr; ptr++, str++)
+                       *str = *ptr;
+       else
+               *str++ = '0';
+       *str = '\0';
+
+       return str - out;
+}
+
+static int xdl_format_hunk_hdr(long s1, long c1, long s2, long c2,
+                              const char *func, long funclen,
+                              xdemitcb_t *ecb) {
+       int nb = 0;
+       mmbuffer_t mb;
+       char buf[128];
+
+       memcpy(buf, "@@ -", 4);
+       nb += 4;
+
+       nb += xdl_num_out(buf + nb, c1 ? s1: s1 - 1);
+
+       if (c1 != 1) {
+               memcpy(buf + nb, ",", 1);
+               nb += 1;
+
+               nb += xdl_num_out(buf + nb, c1);
+       }
+
+       memcpy(buf + nb, " +", 2);
+       nb += 2;
+
+       nb += xdl_num_out(buf + nb, c2 ? s2: s2 - 1);
+
+       if (c2 != 1) {
+               memcpy(buf + nb, ",", 1);
+               nb += 1;
+
+               nb += xdl_num_out(buf + nb, c2);
+       }
+
+       memcpy(buf + nb, " @@", 3);
+       nb += 3;
+       if (func && funclen) {
+               buf[nb++] = ' ';
+               if (funclen > sizeof(buf) - nb - 1)
+                       funclen = sizeof(buf) - nb - 1;
+               memcpy(buf + nb, func, funclen);
+               nb += funclen;
+       }
+       buf[nb++] = '\n';
+
+       mb.ptr = buf;
+       mb.size = nb;
+       if (ecb->out_line(ecb->priv, &mb, 1) < 0)
+               return -1;
+       return 0;
+}
+
+int xdl_emit_hunk_hdr(long s1, long c1, long s2, long c2,
+                     const char *func, long funclen,
+                     xdemitcb_t *ecb) {
+       if (!ecb->out_hunk)
+               return xdl_format_hunk_hdr(s1, c1, s2, c2, func, funclen, ecb);
+       if (ecb->out_hunk(ecb->priv,
+                         c1 ? s1 : s1 - 1, c1,
+                         c2 ? s2 : s2 - 1, c2,
+                         func, funclen) < 0)
+               return -1;
+       return 0;
+}
+
+int xdl_fall_back_diff(xdfenv_t *diff_env, xpparam_t const *xpp,
+               int line1, int count1, int line2, int count2)
+{
+       /*
+        * This probably does not work outside Git, since
+        * we have a very simple mmfile structure.
+        *
+        * Note: ideally, we would reuse the prepared environment, but
+        * the libxdiff interface does not (yet) allow for diffing only
+        * ranges of lines instead of the whole files.
+        */
+       mmfile_t subfile1, subfile2;
+       xdfenv_t env;
+
+       subfile1.ptr = (char *)diff_env->xdf1.recs[line1 - 1]->ptr;
+       subfile1.size = diff_env->xdf1.recs[line1 + count1 - 2]->ptr +
+               diff_env->xdf1.recs[line1 + count1 - 2]->size - subfile1.ptr;
+       subfile2.ptr = (char *)diff_env->xdf2.recs[line2 - 1]->ptr;
+       subfile2.size = diff_env->xdf2.recs[line2 + count2 - 2]->ptr +
+               diff_env->xdf2.recs[line2 + count2 - 2]->size - subfile2.ptr;
+       if (xdl_do_diff(&subfile1, &subfile2, xpp, &env) < 0)
+               return -1;
+
+       memcpy(diff_env->xdf1.rchg + line1 - 1, env.xdf1.rchg, count1);
+       memcpy(diff_env->xdf2.rchg + line2 - 1, env.xdf2.rchg, count2);
+
+       xdl_free_env(&env);
+
+       return 0;
+}
+
+void* xdl_alloc_grow_helper(void *p, long nr, long *alloc, size_t size)
+{
+       void *tmp = NULL;
+       size_t n = ((LONG_MAX - 16) / 2 >= *alloc) ? 2 * *alloc + 16 : LONG_MAX;
+       if (nr > n)
+               n = nr;
+       if (SIZE_MAX / size >= n)
+               tmp = xdl_realloc(p, n * size);
+       if (tmp) {
+               *alloc = n;
+       } else {
+               xdl_free(p);
+               *alloc = 0;
+       }
+       return tmp;
+}
diff --git a/xutils.h b/xutils.h
new file mode 100644 (file)
index 0000000..fd0bba9
--- /dev/null
+++ b/xutils.h
@@ -0,0 +1,48 @@
+/*
+ *  LibXDiff by Davide Libenzi ( File Differential Library )
+ *  Copyright (C) 2003  Davide Libenzi
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Lesser General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 2.1 of the License, or (at your option) any later version.
+ *
+ *  This library is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public
+ *  License along with this library; if not, see
+ *  <http://www.gnu.org/licenses/>.
+ *
+ *  Davide Libenzi <davidel@xmailserver.org>
+ *
+ */
+
+#if !defined(XUTILS_H)
+#define XUTILS_H
+
+
+
+long xdl_bogosqrt(long n);
+int xdl_emit_diffrec(char const *rec, long size, char const *pre, long psize,
+                    xdemitcb_t *ecb);
+int xdl_cha_init(chastore_t *cha, long isize, long icount);
+void xdl_cha_free(chastore_t *cha);
+void *xdl_cha_alloc(chastore_t *cha);
+long xdl_guess_lines(mmfile_t *mf, long sample);
+int xdl_blankline(const char *line, long size, long flags);
+int xdl_recmatch(const char *l1, long s1, const char *l2, long s2, long flags);
+unsigned long xdl_hash_record(char const **data, char const *top, long flags);
+unsigned int xdl_hashbits(unsigned int size);
+int xdl_num_out(char *out, long val);
+int xdl_emit_hunk_hdr(long s1, long c1, long s2, long c2,
+                     const char *func, long funclen, xdemitcb_t *ecb);
+int xdl_fall_back_diff(xdfenv_t *diff_env, xpparam_t const *xpp,
+                      int line1, int count1, int line2, int count2);
+
+/* Do not call this function, use XDL_ALLOC_GROW instead */
+void* xdl_alloc_grow_helper(void* p, long nr, long* alloc, size_t size);
+
+#endif /* #if !defined(XUTILS_H) */