[thirdparty/git.git] / xdiff / xutils.c

/*
 *  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, write to the Free Software
 *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
 *
 *  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->outf(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;
}


void *xdl_cha_first(chastore_t *cha) {
	chanode_t *sncur;

	if (!(cha->sncur = sncur = cha->head))
		return NULL;

	cha->scurr = 0;

	return (char *) sncur + sizeof(chanode_t) + cha->scurr;
}


void *xdl_cha_next(chastore_t *cha) {
	chanode_t *sncur;

	if (!(sncur = cha->sncur))
		return NULL;
	cha->scurr += cha->isize;
	if (cha->scurr == sncur->icurr) {
		if (!(sncur = cha->sncur = sncur->next))
			return NULL;
		cha->scurr = 0;
	}

	return (char *) sncur + sizeof(chanode_t) + cha->scurr;
}


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)) != NULL) {
		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_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.
	 *
	 * 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++])
			; /* keep going */
	}

	/*
	 * 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;

	for (; ptr < top && *ptr != '\n'; ptr++) {
		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;
}


long xdl_atol(char const *str, char const **next) {
	long val, base;
	char const *top;

	for (top = str; XDL_ISDIGIT(*top); top++);
	if (next)
		*next = top;
	for (val = 0, base = 1, top--; top >= str; top--, base *= 10)
		val += base * (long)(*top - '0');
	return val;
}


int xdl_emit_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->outf(ecb->priv, &mb, 1) < 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;
}
Commit	Line	Data
3443546f LT	1	/*
	2	* LibXDiff by Davide Libenzi ( File Differential Library )
	3	* Copyright (C) 2003 Davide Libenzi
	4	*
	5	* This library is free software; you can redistribute it and/or
	6	* modify it under the terms of the GNU Lesser General Public
	7	* License as published by the Free Software Foundation; either
	8	* version 2.1 of the License, or (at your option) any later version.
	9	*
	10	* This library is distributed in the hope that it will be useful,
	11	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	12	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	13	* Lesser General Public License for more details.
	14	*
	15	* You should have received a copy of the GNU Lesser General Public
	16	* License along with this library; if not, write to the Free Software
	17	* Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
	18	*
	19	* Davide Libenzi <davidel@xmailserver.org>
	20	*
	21	*/
	22
	23	#include "xinclude.h"
	24
	25
	26
3443546f	27
ca557aff DL	28	long xdl_bogosqrt(long n) {
	29	long i;
	30
	31	/*
	32	* Classical integer square root approximation using shifts.
	33	*/
	34	for (i = 1; n > 0; n >>= 2)
	35	i <<= 1;
	36
	37	return i;
	38	}
	39
	40
3443546f LT	41	int xdl_emit_diffrec(char const rec, long size, char const pre, long psize,
3443546f LT	42	xdemitcb_t *ecb) {
d281786f	43	int i = 2;
621c53cc	44	mmbuffer_t mb[3];
3443546f LT	45
	46	mb[0].ptr = (char *) pre;
	47	mb[0].size = psize;
	48	mb[1].ptr = (char *) rec;
	49	mb[1].size = size;
d281786f JH	50	if (size > 0 && rec[size - 1] != '\n') {
d281786f JH	51	mb[2].ptr = (char *) "\n\\ No newline at end of file\n";
621c53cc	52	mb[2].size = strlen(mb[2].ptr);
d281786f	53	i++;
621c53cc	54	}
621c53cc	55	if (ecb->outf(ecb->priv, mb, i) < 0) {
3443546f LT	56
	57	return -1;
	58	}
	59
	60	return 0;
	61	}
	62
	63	void xdl_mmfile_first(mmfile_t mmf, long *size)
	64	{
	65	*size = mmf->size;
	66	return mmf->ptr;
	67	}
	68
	69
3443546f LT	70	long xdl_mmfile_size(mmfile_t *mmf)
	71	{
	72	return mmf->size;
	73	}
	74
	75
	76	int xdl_cha_init(chastore_t *cha, long isize, long icount) {
	77
	78	cha->head = cha->tail = NULL;
	79	cha->isize = isize;
	80	cha->nsize = icount * isize;
	81	cha->ancur = cha->sncur = NULL;
	82	cha->scurr = 0;
	83
	84	return 0;
	85	}
	86
	87
	88	void xdl_cha_free(chastore_t *cha) {
	89	chanode_t cur, tmp;
	90
	91	for (cur = cha->head; (tmp = cur) != NULL;) {
	92	cur = cur->next;
	93	xdl_free(tmp);
	94	}
	95	}
	96
	97
	98	void xdl_cha_alloc(chastore_t cha) {
	99	chanode_t *ancur;
	100	void *data;
	101
	102	if (!(ancur = cha->ancur) \|\| ancur->icurr == cha->nsize) {
	103	if (!(ancur = (chanode_t *) xdl_malloc(sizeof(chanode_t) + cha->nsize))) {
	104
	105	return NULL;
	106	}
	107	ancur->icurr = 0;
	108	ancur->next = NULL;
	109	if (cha->tail)
	110	cha->tail->next = ancur;
	111	if (!cha->head)
	112	cha->head = ancur;
	113	cha->tail = ancur;
	114	cha->ancur = ancur;
	115	}
	116
	117	data = (char *) ancur + sizeof(chanode_t) + ancur->icurr;
	118	ancur->icurr += cha->isize;
	119
	120	return data;
	121	}
	122
	123
	124	void xdl_cha_first(chastore_t cha) {
	125	chanode_t *sncur;
	126
	127	if (!(cha->sncur = sncur = cha->head))
	128	return NULL;
	129
	130	cha->scurr = 0;
	131
	132	return (char *) sncur + sizeof(chanode_t) + cha->scurr;
	133	}
134
135
136	void xdl_cha_next(chastore_t cha) {
137	chanode_t *sncur;
138
139	if (!(sncur = cha->sncur))
140	return NULL;
141	cha->scurr += cha->isize;
142	if (cha->scurr == sncur->icurr) {
143	if (!(sncur = cha->sncur = sncur->next))
144	return NULL;
145	cha->scurr = 0;
146	}
147
148	return (char *) sncur + sizeof(chanode_t) + cha->scurr;
149	}
150
151
86abba80	152	long xdl_guess_lines(mmfile_t *mf, long sample) {
3443546f LT	153	long nl = 0, size, tsize = 0;
	154	char const data, cur, *top;
	155
	156	if ((cur = data = xdl_mmfile_first(mf, &size)) != NULL) {
739864b1	157	for (top = data + size; nl < sample && cur < top; ) {
3443546f LT	158	nl++;
	159	if (!(cur = memchr(cur, '\n', top - cur)))
	160	cur = top;
	161	else
	162	cur++;
	163	}
	164	tsize += (long) (cur - data);
	165	}
	166
	167	if (nl && tsize)
	168	nl = xdl_mmfile_size(mf) / (tsize / nl);
	169
	170	return nl + 1;
	171	}
	172
0d21efa5 JS	173	int xdl_recmatch(const char l1, long s1, const char l2, long s2, long flags)
	174	{
	175	int i1, i2;
	176
b4cf0f17 DR	177	if (s1 == s2 && !memcmp(l1, l2, s1))
b4cf0f17 DR	178	return 1;
3b5ef0e2	179	if (!(flags & XDF_WHITESPACE_FLAGS))
b4cf0f17	180	return 0;
3b5ef0e2 JH	181
	182	i1 = 0;
	183	i2 = 0;
	184
	185	/*
	186	* -w matches everything that matches with -b, and -b in turn
	187	* matches everything that matches with --ignore-space-at-eol.
	188	*
	189	* Each flavor of ignoring needs different logic to skip whitespaces
	190	* while we have both sides to compare.
	191	*/
0d21efa5	192	if (flags & XDF_IGNORE_WHITESPACE) {
3b5ef0e2 JH	193	goto skip_ws;
	194	while (i1 < s1 && i2 < s2) {
	195	if (l1[i1++] != l2[i2++])
2344d47f	196	return 0;
3b5ef0e2	197	skip_ws:
349362cc	198	while (i1 < s1 && XDL_ISSPACE(l1[i1]))
3b5ef0e2	199	i1++;
349362cc	200	while (i2 < s2 && XDL_ISSPACE(l2[i2]))
3b5ef0e2	201	i2++;
0d21efa5	202	}
0d21efa5	203	} else if (flags & XDF_IGNORE_WHITESPACE_CHANGE) {
3b5ef0e2	204	while (i1 < s1 && i2 < s2) {
349362cc	205	if (XDL_ISSPACE(l1[i1]) && XDL_ISSPACE(l2[i2])) {
3b5ef0e2	206	/* Skip matching spaces and try again */
349362cc	207	while (i1 < s1 && XDL_ISSPACE(l1[i1]))
859f9c45	208	i1++;
349362cc	209	while (i2 < s2 && XDL_ISSPACE(l2[i2]))
859f9c45	210	i2++;
3b5ef0e2	211	continue;
859f9c45	212	}
3b5ef0e2 JH	213	if (l1[i1++] != l2[i2++])
	214	return 0;
	215	}
	216	} else if (flags & XDF_IGNORE_WHITESPACE_AT_EOL) {
	217	while (i1 < s1 && i2 < s2 && l1[i1++] == l2[i2++])
	218	; /* keep going */
	219	}
	220
	221	/*
	222	* After running out of one side, the remaining side must have
	223	* nothing but whitespace for the lines to match. Note that
	224	* ignore-whitespace-at-eol case may break out of the loop
	225	* while there still are characters remaining on both lines.
	226	*/
	227	if (i1 < s1) {
349362cc	228	while (i1 < s1 && XDL_ISSPACE(l1[i1]))
859f9c45	229	i1++;
3b5ef0e2 JH	230	if (s1 != i1)
	231	return 0;
	232	}
	233	if (i2 < s2) {
349362cc	234	while (i2 < s2 && XDL_ISSPACE(l2[i2]))
859f9c45	235	i2++;
3b5ef0e2 JH	236	return (s2 == i2);
	237	}
	238	return 1;
0d21efa5	239	}
3443546f	240
824f782c JS	241	static unsigned long xdl_hash_record_with_whitespace(char const **data,
824f782c JS	242	char const *top, long flags) {
3443546f LT	243	unsigned long ha = 5381;
	244	char const ptr = data;
	245
	246	for (; ptr < top && *ptr != '\n'; ptr++) {
349362cc	247	if (XDL_ISSPACE(*ptr)) {
859f9c45	248	const char *ptr2 = ptr;
78ed710f	249	int at_eol;
349362cc	250	while (ptr + 1 < top && XDL_ISSPACE(ptr[1])
2344d47f	251	&& ptr[1] != '\n')
0d21efa5	252	ptr++;
78ed710f	253	at_eol = (top <= ptr + 1 \|\| ptr[1] == '\n');
6d12acef KC	254	if (flags & XDF_IGNORE_WHITESPACE)
	255	; /* already handled */
	256	else if (flags & XDF_IGNORE_WHITESPACE_CHANGE
78ed710f	257	&& !at_eol) {
0d21efa5 JS	258	ha += (ha << 5);
	259	ha ^= (unsigned long) ' ';
	260	}
6d12acef	261	else if (flags & XDF_IGNORE_WHITESPACE_AT_EOL
78ed710f	262	&& !at_eol) {
859f9c45 JS	263	while (ptr2 != ptr + 1) {
	264	ha += (ha << 5);
	265	ha ^= (unsigned long) *ptr2;
	266	ptr2++;
	267	}
	268	}
0d21efa5 JS	269	continue;
0d21efa5 JS	270	}
3443546f LT	271	ha += (ha << 5);
	272	ha ^= (unsigned long) *ptr;
	273	}
	274	*data = ptr < top ? ptr + 1: ptr;
	275
	276	return ha;
	277	}
	278
	279
824f782c JS	280	unsigned long xdl_hash_record(char const *data, char const top, long flags) {
	281	unsigned long ha = 5381;
	282	char const ptr = data;
	283
	284	if (flags & XDF_WHITESPACE_FLAGS)
	285	return xdl_hash_record_with_whitespace(data, top, flags);
	286
	287	for (; ptr < top && *ptr != '\n'; ptr++) {
	288	ha += (ha << 5);
	289	ha ^= (unsigned long) *ptr;
	290	}
	291	*data = ptr < top ? ptr + 1: ptr;
	292
	293	return ha;
	294	}
	295
	296
3443546f LT	297	unsigned int xdl_hashbits(unsigned int size) {
	298	unsigned int val = 1, bits = 0;
	299
	300	for (; val < size && bits < CHAR_BIT * sizeof(unsigned int); val <<= 1, bits++);
	301	return bits ? bits: 1;
	302	}
	303
	304
	305	int xdl_num_out(char *out, long val) {
	306	char ptr, str = out;
	307	char buf[32];
	308
	309	ptr = buf + sizeof(buf) - 1;
	310	*ptr = '\0';
	311	if (val < 0) {
	312	*--ptr = '-';
	313	val = -val;
	314	}
	315	for (; val && ptr > buf; val /= 10)
	316	*--ptr = "0123456789"[val % 10];
	317	if (*ptr)
	318	for (; *ptr; ptr++, str++)
	319	str = ptr;
	320	else
	321	*str++ = '0';
	322	*str = '\0';
	323
	324	return str - out;
	325	}
	326
	327
	328	long xdl_atol(char const str, char const *next) {
	329	long val, base;
	330	char const *top;
	331
	332	for (top = str; XDL_ISDIGIT(*top); top++);
	333	if (next)
	334	*next = top;
	335	for (val = 0, base = 1, top--; top >= str; top--, base *= 10)
	336	val += base * (long)(*top - '0');
	337	return val;
	338	}
	339
	340
acb72577 MW	341	int xdl_emit_hunk_hdr(long s1, long c1, long s2, long c2,
acb72577 MW	342	const char func, long funclen, xdemitcb_t ecb) {
3443546f LT	343	int nb = 0;
	344	mmbuffer_t mb;
	345	char buf[128];
	346
	347	memcpy(buf, "@@ -", 4);
	348	nb += 4;
	349
ca557aff	350	nb += xdl_num_out(buf + nb, c1 ? s1: s1 - 1);
3443546f	351
3ce8f089 JH	352	if (c1 != 1) {
	353	memcpy(buf + nb, ",", 1);
	354	nb += 1;
3443546f	355
3ce8f089 JH	356	nb += xdl_num_out(buf + nb, c1);
3ce8f089 JH	357	}
3443546f LT	358
	359	memcpy(buf + nb, " +", 2);
	360	nb += 2;
	361
ca557aff	362	nb += xdl_num_out(buf + nb, c2 ? s2: s2 - 1);
3443546f	363
3ce8f089 JH	364	if (c2 != 1) {
	365	memcpy(buf + nb, ",", 1);
	366	nb += 1;
3443546f	367
3ce8f089 JH	368	nb += xdl_num_out(buf + nb, c2);
3ce8f089 JH	369	}
3443546f	370
acb72577 MW	371	memcpy(buf + nb, " @@", 3);
	372	nb += 3;
	373	if (func && funclen) {
	374	buf[nb++] = ' ';
	375	if (funclen > sizeof(buf) - nb - 1)
	376	funclen = sizeof(buf) - nb - 1;
	377	memcpy(buf + nb, func, funclen);
	378	nb += funclen;
	379	}
	380	buf[nb++] = '\n';
3443546f LT	381
	382	mb.ptr = buf;
	383	mb.size = nb;
	384	if (ecb->outf(ecb->priv, &mb, 1) < 0)
	385	return -1;
	386
	387	return 0;
	388	}
1d26b252 TRC	389
	390	int xdl_fall_back_diff(xdfenv_t diff_env, xpparam_t const xpp,
	391	int line1, int count1, int line2, int count2)
	392	{
	393	/*
	394	* This probably does not work outside Git, since
	395	* we have a very simple mmfile structure.
	396	*
	397	* Note: ideally, we would reuse the prepared environment, but
	398	* the libxdiff interface does not (yet) allow for diffing only
	399	* ranges of lines instead of the whole files.
	400	*/
	401	mmfile_t subfile1, subfile2;
	402	xdfenv_t env;
	403
	404	subfile1.ptr = (char *)diff_env->xdf1.recs[line1 - 1]->ptr;
	405	subfile1.size = diff_env->xdf1.recs[line1 + count1 - 2]->ptr +
	406	diff_env->xdf1.recs[line1 + count1 - 2]->size - subfile1.ptr;
	407	subfile2.ptr = (char *)diff_env->xdf2.recs[line2 - 1]->ptr;
	408	subfile2.size = diff_env->xdf2.recs[line2 + count2 - 2]->ptr +
	409	diff_env->xdf2.recs[line2 + count2 - 2]->size - subfile2.ptr;
	410	if (xdl_do_diff(&subfile1, &subfile2, xpp, &env) < 0)
	411	return -1;
	412
	413	memcpy(diff_env->xdf1.rchg + line1 - 1, env.xdf1.rchg, count1);
	414	memcpy(diff_env->xdf2.rchg + line2 - 1, env.xdf2.rchg, count2);
	415
	416	xdl_free_env(&env);
	417
	418	return 0;
	419	}