Merge branch 'rb/hpe'
[git.git] / xdiff / xutils.c
blob963e1c58b9049f1b9ee94537171bd3c6cd21680f
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, see
17 * <http://www.gnu.org/licenses/>.
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->out_line(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);
160 * Have we eaten everything on the line, except for an optional
161 * CR at the very end?
163 static int ends_with_optional_cr(const char *l, long s, long i)
165 int complete = s && l[s-1] == '\n';
167 if (complete)
168 s--;
169 if (s == i)
170 return 1;
171 /* do not ignore CR at the end of an incomplete line */
172 if (complete && s == i + 1 && l[i] == '\r')
173 return 1;
174 return 0;
177 int xdl_recmatch(const char *l1, long s1, const char *l2, long s2, long flags)
179 int i1, i2;
181 if (s1 == s2 && !memcmp(l1, l2, s1))
182 return 1;
183 if (!(flags & XDF_WHITESPACE_FLAGS))
184 return 0;
186 i1 = 0;
187 i2 = 0;
190 * -w matches everything that matches with -b, and -b in turn
191 * matches everything that matches with --ignore-space-at-eol,
192 * which in turn matches everything that matches with --ignore-cr-at-eol.
194 * Each flavor of ignoring needs different logic to skip whitespaces
195 * while we have both sides to compare.
197 if (flags & XDF_IGNORE_WHITESPACE) {
198 goto skip_ws;
199 while (i1 < s1 && i2 < s2) {
200 if (l1[i1++] != l2[i2++])
201 return 0;
202 skip_ws:
203 while (i1 < s1 && XDL_ISSPACE(l1[i1]))
204 i1++;
205 while (i2 < s2 && XDL_ISSPACE(l2[i2]))
206 i2++;
208 } else if (flags & XDF_IGNORE_WHITESPACE_CHANGE) {
209 while (i1 < s1 && i2 < s2) {
210 if (XDL_ISSPACE(l1[i1]) && XDL_ISSPACE(l2[i2])) {
211 /* Skip matching spaces and try again */
212 while (i1 < s1 && XDL_ISSPACE(l1[i1]))
213 i1++;
214 while (i2 < s2 && XDL_ISSPACE(l2[i2]))
215 i2++;
216 continue;
218 if (l1[i1++] != l2[i2++])
219 return 0;
221 } else if (flags & XDF_IGNORE_WHITESPACE_AT_EOL) {
222 while (i1 < s1 && i2 < s2 && l1[i1] == l2[i2]) {
223 i1++;
224 i2++;
226 } else if (flags & XDF_IGNORE_CR_AT_EOL) {
227 /* Find the first difference and see how the line ends */
228 while (i1 < s1 && i2 < s2 && l1[i1] == l2[i2]) {
229 i1++;
230 i2++;
232 return (ends_with_optional_cr(l1, s1, i1) &&
233 ends_with_optional_cr(l2, s2, i2));
237 * After running out of one side, the remaining side must have
238 * nothing but whitespace for the lines to match. Note that
239 * ignore-whitespace-at-eol case may break out of the loop
240 * while there still are characters remaining on both lines.
242 if (i1 < s1) {
243 while (i1 < s1 && XDL_ISSPACE(l1[i1]))
244 i1++;
245 if (s1 != i1)
246 return 0;
248 if (i2 < s2) {
249 while (i2 < s2 && XDL_ISSPACE(l2[i2]))
250 i2++;
251 return (s2 == i2);
253 return 1;
256 static unsigned long xdl_hash_record_with_whitespace(char const **data,
257 char const *top, long flags) {
258 unsigned long ha = 5381;
259 char const *ptr = *data;
260 int cr_at_eol_only = (flags & XDF_WHITESPACE_FLAGS) == XDF_IGNORE_CR_AT_EOL;
262 for (; ptr < top && *ptr != '\n'; ptr++) {
263 if (cr_at_eol_only) {
264 /* do not ignore CR at the end of an incomplete line */
265 if (*ptr == '\r' &&
266 (ptr + 1 < top && ptr[1] == '\n'))
267 continue;
269 else if (XDL_ISSPACE(*ptr)) {
270 const char *ptr2 = ptr;
271 int at_eol;
272 while (ptr + 1 < top && XDL_ISSPACE(ptr[1])
273 && ptr[1] != '\n')
274 ptr++;
275 at_eol = (top <= ptr + 1 || ptr[1] == '\n');
276 if (flags & XDF_IGNORE_WHITESPACE)
277 ; /* already handled */
278 else if (flags & XDF_IGNORE_WHITESPACE_CHANGE
279 && !at_eol) {
280 ha += (ha << 5);
281 ha ^= (unsigned long) ' ';
283 else if (flags & XDF_IGNORE_WHITESPACE_AT_EOL
284 && !at_eol) {
285 while (ptr2 != ptr + 1) {
286 ha += (ha << 5);
287 ha ^= (unsigned long) *ptr2;
288 ptr2++;
291 continue;
293 ha += (ha << 5);
294 ha ^= (unsigned long) *ptr;
296 *data = ptr < top ? ptr + 1: ptr;
298 return ha;
301 unsigned long xdl_hash_record(char const **data, char const *top, long flags) {
302 unsigned long ha = 5381;
303 char const *ptr = *data;
305 if (flags & XDF_WHITESPACE_FLAGS)
306 return xdl_hash_record_with_whitespace(data, top, flags);
308 for (; ptr < top && *ptr != '\n'; ptr++) {
309 ha += (ha << 5);
310 ha ^= (unsigned long) *ptr;
312 *data = ptr < top ? ptr + 1: ptr;
314 return ha;
317 unsigned int xdl_hashbits(unsigned int size) {
318 unsigned int val = 1, bits = 0;
320 for (; val < size && bits < CHAR_BIT * sizeof(unsigned int); val <<= 1, bits++);
321 return bits ? bits: 1;
325 int xdl_num_out(char *out, long val) {
326 char *ptr, *str = out;
327 char buf[32];
329 ptr = buf + sizeof(buf) - 1;
330 *ptr = '\0';
331 if (val < 0) {
332 *--ptr = '-';
333 val = -val;
335 for (; val && ptr > buf; val /= 10)
336 *--ptr = "0123456789"[val % 10];
337 if (*ptr)
338 for (; *ptr; ptr++, str++)
339 *str = *ptr;
340 else
341 *str++ = '0';
342 *str = '\0';
344 return str - out;
347 static int xdl_format_hunk_hdr(long s1, long c1, long s2, long c2,
348 const char *func, long funclen,
349 xdemitcb_t *ecb) {
350 int nb = 0;
351 mmbuffer_t mb;
352 char buf[128];
354 memcpy(buf, "@@ -", 4);
355 nb += 4;
357 nb += xdl_num_out(buf + nb, c1 ? s1: s1 - 1);
359 if (c1 != 1) {
360 memcpy(buf + nb, ",", 1);
361 nb += 1;
363 nb += xdl_num_out(buf + nb, c1);
366 memcpy(buf + nb, " +", 2);
367 nb += 2;
369 nb += xdl_num_out(buf + nb, c2 ? s2: s2 - 1);
371 if (c2 != 1) {
372 memcpy(buf + nb, ",", 1);
373 nb += 1;
375 nb += xdl_num_out(buf + nb, c2);
378 memcpy(buf + nb, " @@", 3);
379 nb += 3;
380 if (func && funclen) {
381 buf[nb++] = ' ';
382 if (funclen > sizeof(buf) - nb - 1)
383 funclen = sizeof(buf) - nb - 1;
384 memcpy(buf + nb, func, funclen);
385 nb += funclen;
387 buf[nb++] = '\n';
389 mb.ptr = buf;
390 mb.size = nb;
391 if (ecb->out_line(ecb->priv, &mb, 1) < 0)
392 return -1;
393 return 0;
396 int xdl_emit_hunk_hdr(long s1, long c1, long s2, long c2,
397 const char *func, long funclen,
398 xdemitcb_t *ecb) {
399 if (!ecb->out_hunk)
400 return xdl_format_hunk_hdr(s1, c1, s2, c2, func, funclen, ecb);
401 if (ecb->out_hunk(ecb->priv,
402 c1 ? s1 : s1 - 1, c1,
403 c2 ? s2 : s2 - 1, c2,
404 func, funclen) < 0)
405 return -1;
406 return 0;
409 int xdl_fall_back_diff(xdfenv_t *diff_env, xpparam_t const *xpp,
410 int line1, int count1, int line2, int count2)
413 * This probably does not work outside Git, since
414 * we have a very simple mmfile structure.
416 * Note: ideally, we would reuse the prepared environment, but
417 * the libxdiff interface does not (yet) allow for diffing only
418 * ranges of lines instead of the whole files.
420 mmfile_t subfile1, subfile2;
421 xdfenv_t env;
423 subfile1.ptr = (char *)diff_env->xdf1.recs[line1 - 1]->ptr;
424 subfile1.size = diff_env->xdf1.recs[line1 + count1 - 2]->ptr +
425 diff_env->xdf1.recs[line1 + count1 - 2]->size - subfile1.ptr;
426 subfile2.ptr = (char *)diff_env->xdf2.recs[line2 - 1]->ptr;
427 subfile2.size = diff_env->xdf2.recs[line2 + count2 - 2]->ptr +
428 diff_env->xdf2.recs[line2 + count2 - 2]->size - subfile2.ptr;
429 if (xdl_do_diff(&subfile1, &subfile2, xpp, &env) < 0)
430 return -1;
432 memcpy(diff_env->xdf1.rchg + line1 - 1, env.xdf1.rchg, count1);
433 memcpy(diff_env->xdf2.rchg + line2 - 1, env.xdf2.rchg, count2);
435 xdl_free_env(&env);
437 return 0;