xdiff: delete redundant array xdfile_t.ha

When 0 <= i < xdfile_t.nreff the following is true:
xdfile_t.ha[i] == xdfile_t.recs[xdfile_t.rindex[i]]

This makes the code about 5% slower. The fields rindex and ha are
specific to the classic diff (myers and minimal). I plan on creating a
struct for classic diff, but there's a lot of cleanup that needs to be
done before that can happen and leaving ha in would make those cleanups
harder to follow.

A subsequent commit will delete the chastore cha from xdfile_t. That
later commit will investigate deleting ha and cha independently and
together.

Signed-off-by: Ezekiel Newren <ezekielnewren@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff --git a/xdiff/xdiffi.c b/xdiff/xdiffi.c
index bbf0161f847aabb90fa115ee827fab5637383029..11cd090b534e61bf7742a7803f20d6f967ef0033 100644 (file)
--- a/xdiff/xdiffi.c
+++ b/xdiff/xdiffi.c
@@ -22,6 +22,11 @@
 
 #include "xinclude.h"
 
+static unsigned long get_hash(xdfile_t *xdf, long index)
+{
+       return xdf->recs[xdf->rindex[index]]->ha;
+}
+
 #define XDL_MAX_COST_MIN 256
 #define XDL_HEUR_MIN_COST 256
 #define XDL_LINE_MAX (long)((1UL << (CHAR_BIT * sizeof(long) - 1)) - 1)
@@ -42,8 +47,8 @@ typedef struct s_xdpsplit {
  * 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,
+static long xdl_split(xdfile_t *xdf1, long off1, long lim1,
+                     xdfile_t *xdf2, long off2, long lim2,
                      long *kvdf, long *kvdb, int need_min, xdpsplit_t *spl,
                      xdalgoenv_t *xenv) {
        long dmin = off1 - lim2, dmax = lim1 - off2;
@@ -87,7 +92,7 @@ static long xdl_split(unsigned long const *ha1, long off1, long lim1,
                                i1 = kvdf[d + 1];
                        prev1 = i1;
                        i2 = i1 - d;
-                       for (; i1 < lim1 && i2 < lim2 && ha1[i1] == ha2[i2]; i1++, i2++);
+                       for (; i1 < lim1 && i2 < lim2 && get_hash(xdf1, i1) == get_hash(xdf2, i2); i1++, i2++);
                        if (i1 - prev1 > xenv->snake_cnt)
                                got_snake = 1;
                        kvdf[d] = i1;
@@ -124,7 +129,7 @@ static long xdl_split(unsigned long const *ha1, long off1, long lim1,
                                i1 = kvdb[d + 1] - 1;
                        prev1 = i1;
                        i2 = i1 - d;
-                       for (; i1 > off1 && i2 > off2 && ha1[i1 - 1] == ha2[i2 - 1]; i1--, i2--);
+                       for (; i1 > off1 && i2 > off2 && get_hash(xdf1, i1 - 1) == get_hash(xdf2, i2 - 1); i1--, i2--);
                        if (prev1 - i1 > xenv->snake_cnt)
                                got_snake = 1;
                        kvdb[d] = i1;
@@ -159,7 +164,7 @@ static long xdl_split(unsigned long const *ha1, long off1, long lim1,
                                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++)
+                                       for (k = 1; get_hash(xdf1, i1 - k) == get_hash(xdf2, i2 - k); k++)
                                                if (k == xenv->snake_cnt) {
                                                        best = v;
                                                        spl->i1 = i1;
@@ -183,7 +188,7 @@ static long xdl_split(unsigned long const *ha1, long off1, long lim1,
                                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++)
+                                       for (k = 0; get_hash(xdf1, i1 + k) == get_hash(xdf2, i2 + k); k++)
                                                if (k == xenv->snake_cnt - 1) {
                                                        best = v;
                                                        spl->i1 = i1;
@@ -260,13 +265,12 @@ static long xdl_split(unsigned long const *ha1, long off1, long lim1,
 int xdl_recs_cmp(xdfile_t *xdf1, long off1, long lim1,
                 xdfile_t *xdf2, long off2, long lim2,
                 long *kvdf, long *kvdb, int need_min, xdalgoenv_t *xenv) {
-       unsigned long const *ha1 = xdf1->ha, *ha2 = xdf2->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--);
+       for (; off1 < lim1 && off2 < lim2 && get_hash(xdf1, off1) == get_hash(xdf2, off2); off1++, off2++);
+       for (; off1 < lim1 && off2 < lim2 && get_hash(xdf1, lim1 - 1) == get_hash(xdf2, lim2 - 1); lim1--, lim2--);
 
        /*
         * If one dimension is empty, then all records on the other one must
@@ -285,7 +289,7 @@ int xdl_recs_cmp(xdfile_t *xdf1, long off1, long lim1,
                /*
                 * Divide ...
                 */
-               if (xdl_split(ha1, off1, lim1, ha2, off2, lim2, kvdf, kvdb,
+               if (xdl_split(xdf1, off1, lim1, xdf2, off2, lim2, kvdf, kvdb,
                              need_min, &spl, xenv) < 0) {
 
                        return -1;

diff --git a/xdiff/xprepare.c b/xdiff/xprepare.c
index 3576415c85cb7a696ea1620d60651823a6bc8526..22c44f06835138a4a25be3182721ff2714eb8b24 100644 (file)
--- a/xdiff/xprepare.c
+++ b/xdiff/xprepare.c
@@ -133,7 +133,6 @@ static void xdl_free_ctx(xdfile_t *xdf)
 {
        xdl_free(xdf->rindex);
        xdl_free(xdf->rchg - 1);
-       xdl_free(xdf->ha);
        xdl_free(xdf->recs);
        xdl_cha_free(&xdf->rcha);
 }
@@ -146,7 +145,6 @@ static int xdl_prepare_ctx(unsigned int pass, mmfile_t *mf, long narec, xpparam_
        char const *blk, *cur, *top, *prev;
        xrecord_t *crec;
 
-       xdf->ha = NULL;
        xdf->rindex = NULL;
        xdf->rchg = NULL;
        xdf->recs = NULL;
@@ -181,8 +179,6 @@ static int xdl_prepare_ctx(unsigned int pass, mmfile_t *mf, long narec, xpparam_
            (XDF_DIFF_ALG(xpp->flags) != XDF_HISTOGRAM_DIFF)) {
                if (!XDL_ALLOC_ARRAY(xdf->rindex, xdf->nrec + 1))
                        goto abort;
-               if (!XDL_ALLOC_ARRAY(xdf->ha, xdf->nrec + 1))
-                       goto abort;
        }
 
        xdf->rchg += 1;
@@ -300,9 +296,7 @@ static int xdl_cleanup_records(xdlclassifier_t *cf, xdfile_t *xdf1, xdfile_t *xd
             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++;
+                       xdf1->rindex[nreff++] = i;
                } else
                        xdf1->rchg[i] = 1;
        }
@@ -312,9 +306,7 @@ static int xdl_cleanup_records(xdlclassifier_t *cf, xdfile_t *xdf1, xdfile_t *xd
             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++;
+                       xdf2->rindex[nreff++] = i;
                } else
                        xdf2->rchg[i] = 1;
        }

diff --git a/xdiff/xtypes.h b/xdiff/xtypes.h
index 8b8467360ecfc0e368e8a8abeb6f61d55063b0c0..85848f1685b6e925d26dd8579c50ee7e657364f9 100644 (file)
--- a/xdiff/xtypes.h
+++ b/xdiff/xtypes.h
@@ -52,7 +52,6 @@ typedef struct s_xdfile {
        char *rchg;
        long *rindex;
        long nreff;
-       unsigned long *ha;
 } xdfile_t;
 
 typedef struct s_xdfenv {