doc: describe git svn init --ignore-refs
[git/git-svn.git] / xdiff / xutils.c
blob04d7b32e4e4a75b9d5762f3d3a2a2f9c236075a0
1 /*
2 * LibXDiff by Davide Libenzi ( File Differential Library )
3 * Copyright (C) 2003 Davide Libenzi
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.
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.
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
19 * Davide Libenzi <davidel@xmailserver.org>
23 #include <limits.h>
24 #include <assert.h>
25 #include "xinclude.h"
30 long xdl_bogosqrt(long n) {
31 long i;
34 * Classical integer square root approximation using shifts.
36 for (i = 1; n > 0; n >>= 2)
37 i <<= 1;
39 return i;
43 int xdl_emit_diffrec(char const *rec, long size, char const *pre, long psize,
44 xdemitcb_t *ecb) {
45 int i = 2;
46 mmbuffer_t mb[3];
48 mb[0].ptr = (char *) pre;
49 mb[0].size = psize;
50 mb[1].ptr = (char *) rec;
51 mb[1].size = size;
52 if (size > 0 && rec[size - 1] != '\n') {
53 mb[2].ptr = (char *) "\n\\ No newline at end of file\n";
54 mb[2].size = strlen(mb[2].ptr);
55 i++;
57 if (ecb->outf(ecb->priv, mb, i) < 0) {
59 return -1;
62 return 0;
65 void *xdl_mmfile_first(mmfile_t *mmf, long *size)
67 *size = mmf->size;
68 return mmf->ptr;
72 long xdl_mmfile_size(mmfile_t *mmf)
74 return mmf->size;
78 int xdl_cha_init(chastore_t *cha, long isize, long icount) {
80 cha->head = cha->tail = NULL;
81 cha->isize = isize;
82 cha->nsize = icount * isize;
83 cha->ancur = cha->sncur = NULL;
84 cha->scurr = 0;
86 return 0;
90 void xdl_cha_free(chastore_t *cha) {
91 chanode_t *cur, *tmp;
93 for (cur = cha->head; (tmp = cur) != NULL;) {
94 cur = cur->next;
95 xdl_free(tmp);
100 void *xdl_cha_alloc(chastore_t *cha) {
101 chanode_t *ancur;
102 void *data;
104 if (!(ancur = cha->ancur) || ancur->icurr == cha->nsize) {
105 if (!(ancur = (chanode_t *) xdl_malloc(sizeof(chanode_t) + cha->nsize))) {
107 return NULL;
109 ancur->icurr = 0;
110 ancur->next = NULL;
111 if (cha->tail)
112 cha->tail->next = ancur;
113 if (!cha->head)
114 cha->head = ancur;
115 cha->tail = ancur;
116 cha->ancur = ancur;
119 data = (char *) ancur + sizeof(chanode_t) + ancur->icurr;
120 ancur->icurr += cha->isize;
122 return data;
125 long xdl_guess_lines(mmfile_t *mf, long sample) {
126 long nl = 0, size, tsize = 0;
127 char const *data, *cur, *top;
129 if ((cur = data = xdl_mmfile_first(mf, &size)) != NULL) {
130 for (top = data + size; nl < sample && cur < top; ) {
131 nl++;
132 if (!(cur = memchr(cur, '\n', top - cur)))
133 cur = top;
134 else
135 cur++;
137 tsize += (long) (cur - data);
140 if (nl && tsize)
141 nl = xdl_mmfile_size(mf) / (tsize / nl);
143 return nl + 1;
146 int xdl_blankline(const char *line, long size, long flags)
148 long i;
150 if (!(flags & XDF_WHITESPACE_FLAGS))
151 return (size <= 1);
153 for (i = 0; i < size && XDL_ISSPACE(line[i]); i++)
156 return (i == size);
159 int xdl_recmatch(const char *l1, long s1, const char *l2, long s2, long flags)
161 int i1, i2;
163 if (s1 == s2 && !memcmp(l1, l2, s1))
164 return 1;
165 if (!(flags & XDF_WHITESPACE_FLAGS))
166 return 0;
168 i1 = 0;
169 i2 = 0;
172 * -w matches everything that matches with -b, and -b in turn
173 * matches everything that matches with --ignore-space-at-eol.
175 * Each flavor of ignoring needs different logic to skip whitespaces
176 * while we have both sides to compare.
178 if (flags & XDF_IGNORE_WHITESPACE) {
179 goto skip_ws;
180 while (i1 < s1 && i2 < s2) {
181 if (l1[i1++] != l2[i2++])
182 return 0;
183 skip_ws:
184 while (i1 < s1 && XDL_ISSPACE(l1[i1]))
185 i1++;
186 while (i2 < s2 && XDL_ISSPACE(l2[i2]))
187 i2++;
189 } else if (flags & XDF_IGNORE_WHITESPACE_CHANGE) {
190 while (i1 < s1 && i2 < s2) {
191 if (XDL_ISSPACE(l1[i1]) && XDL_ISSPACE(l2[i2])) {
192 /* Skip matching spaces and try again */
193 while (i1 < s1 && XDL_ISSPACE(l1[i1]))
194 i1++;
195 while (i2 < s2 && XDL_ISSPACE(l2[i2]))
196 i2++;
197 continue;
199 if (l1[i1++] != l2[i2++])
200 return 0;
202 } else if (flags & XDF_IGNORE_WHITESPACE_AT_EOL) {
203 while (i1 < s1 && i2 < s2 && l1[i1] == l2[i2]) {
204 i1++;
205 i2++;
210 * After running out of one side, the remaining side must have
211 * nothing but whitespace for the lines to match. Note that
212 * ignore-whitespace-at-eol case may break out of the loop
213 * while there still are characters remaining on both lines.
215 if (i1 < s1) {
216 while (i1 < s1 && XDL_ISSPACE(l1[i1]))
217 i1++;
218 if (s1 != i1)
219 return 0;
221 if (i2 < s2) {
222 while (i2 < s2 && XDL_ISSPACE(l2[i2]))
223 i2++;
224 return (s2 == i2);
226 return 1;
229 static unsigned long xdl_hash_record_with_whitespace(char const **data,
230 char const *top, long flags) {
231 unsigned long ha = 5381;
232 char const *ptr = *data;
234 for (; ptr < top && *ptr != '\n'; ptr++) {
235 if (XDL_ISSPACE(*ptr)) {
236 const char *ptr2 = ptr;
237 int at_eol;
238 while (ptr + 1 < top && XDL_ISSPACE(ptr[1])
239 && ptr[1] != '\n')
240 ptr++;
241 at_eol = (top <= ptr + 1 || ptr[1] == '\n');
242 if (flags & XDF_IGNORE_WHITESPACE)
243 ; /* already handled */
244 else if (flags & XDF_IGNORE_WHITESPACE_CHANGE
245 && !at_eol) {
246 ha += (ha << 5);
247 ha ^= (unsigned long) ' ';
249 else if (flags & XDF_IGNORE_WHITESPACE_AT_EOL
250 && !at_eol) {
251 while (ptr2 != ptr + 1) {
252 ha += (ha << 5);
253 ha ^= (unsigned long) *ptr2;
254 ptr2++;
257 continue;
259 ha += (ha << 5);
260 ha ^= (unsigned long) *ptr;
262 *data = ptr < top ? ptr + 1: ptr;
264 return ha;
267 unsigned long xdl_hash_record(char const **data, char const *top, long flags) {
268 unsigned long ha = 5381;
269 char const *ptr = *data;
271 if (flags & XDF_WHITESPACE_FLAGS)
272 return xdl_hash_record_with_whitespace(data, top, flags);
274 for (; ptr < top && *ptr != '\n'; ptr++) {
275 ha += (ha << 5);
276 ha ^= (unsigned long) *ptr;
278 *data = ptr < top ? ptr + 1: ptr;
280 return ha;
283 unsigned int xdl_hashbits(unsigned int size) {
284 unsigned int val = 1, bits = 0;
286 for (; val < size && bits < CHAR_BIT * sizeof(unsigned int); val <<= 1, bits++);
287 return bits ? bits: 1;
291 int xdl_num_out(char *out, long val) {
292 char *ptr, *str = out;
293 char buf[32];
295 ptr = buf + sizeof(buf) - 1;
296 *ptr = '\0';
297 if (val < 0) {
298 *--ptr = '-';
299 val = -val;
301 for (; val && ptr > buf; val /= 10)
302 *--ptr = "0123456789"[val % 10];
303 if (*ptr)
304 for (; *ptr; ptr++, str++)
305 *str = *ptr;
306 else
307 *str++ = '0';
308 *str = '\0';
310 return str - out;
313 int xdl_emit_hunk_hdr(long s1, long c1, long s2, long c2,
314 const char *func, long funclen, xdemitcb_t *ecb) {
315 int nb = 0;
316 mmbuffer_t mb;
317 char buf[128];
319 memcpy(buf, "@@ -", 4);
320 nb += 4;
322 nb += xdl_num_out(buf + nb, c1 ? s1: s1 - 1);
324 if (c1 != 1) {
325 memcpy(buf + nb, ",", 1);
326 nb += 1;
328 nb += xdl_num_out(buf + nb, c1);
331 memcpy(buf + nb, " +", 2);
332 nb += 2;
334 nb += xdl_num_out(buf + nb, c2 ? s2: s2 - 1);
336 if (c2 != 1) {
337 memcpy(buf + nb, ",", 1);
338 nb += 1;
340 nb += xdl_num_out(buf + nb, c2);
343 memcpy(buf + nb, " @@", 3);
344 nb += 3;
345 if (func && funclen) {
346 buf[nb++] = ' ';
347 if (funclen > sizeof(buf) - nb - 1)
348 funclen = sizeof(buf) - nb - 1;
349 memcpy(buf + nb, func, funclen);
350 nb += funclen;
352 buf[nb++] = '\n';
354 mb.ptr = buf;
355 mb.size = nb;
356 if (ecb->outf(ecb->priv, &mb, 1) < 0)
357 return -1;
359 return 0;
362 int xdl_fall_back_diff(xdfenv_t *diff_env, xpparam_t const *xpp,
363 int line1, int count1, int line2, int count2)
366 * This probably does not work outside Git, since
367 * we have a very simple mmfile structure.
369 * Note: ideally, we would reuse the prepared environment, but
370 * the libxdiff interface does not (yet) allow for diffing only
371 * ranges of lines instead of the whole files.
373 mmfile_t subfile1, subfile2;
374 xdfenv_t env;
376 subfile1.ptr = (char *)diff_env->xdf1.recs[line1 - 1]->ptr;
377 subfile1.size = diff_env->xdf1.recs[line1 + count1 - 2]->ptr +
378 diff_env->xdf1.recs[line1 + count1 - 2]->size - subfile1.ptr;
379 subfile2.ptr = (char *)diff_env->xdf2.recs[line2 - 1]->ptr;
380 subfile2.size = diff_env->xdf2.recs[line2 + count2 - 2]->ptr +
381 diff_env->xdf2.recs[line2 + count2 - 2]->size - subfile2.ptr;
382 if (xdl_do_diff(&subfile1, &subfile2, xpp, &env) < 0)
383 return -1;
385 memcpy(diff_env->xdf1.rchg + line1 - 1, env.xdf1.rchg, count1);
386 memcpy(diff_env->xdf2.rchg + line2 - 1, env.xdf2.rchg, count2);
388 xdl_free_env(&env);
390 return 0;