Merge branch 'cc/svn-fe-py-shebang'
[git/git.git] / xdiff / xutils.c
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, see
17 * <http://www.gnu.org/licenses/>.
18 *
19 * Davide Libenzi <davidel@xmailserver.org>
20 *
21 */
22
23 #include "xinclude.h"
24
25
26 long xdl_bogosqrt(long n) {
27 long i;
28
29 /*
30 * Classical integer square root approximation using shifts.
31 */
32 for (i = 1; n > 0; n >>= 2)
33 i <<= 1;
34
35 return i;
36 }
37
38
39 int xdl_emit_diffrec(char const *rec, long size, char const *pre, long psize,
40 xdemitcb_t *ecb) {
41 int i = 2;
42 mmbuffer_t mb[3];
43
44 mb[0].ptr = (char *) pre;
45 mb[0].size = psize;
46 mb[1].ptr = (char *) rec;
47 mb[1].size = size;
48 if (size > 0 && rec[size - 1] != '\n') {
49 mb[2].ptr = (char *) "\n\\ No newline at end of file\n";
50 mb[2].size = strlen(mb[2].ptr);
51 i++;
52 }
53 if (ecb->out_line(ecb->priv, mb, i) < 0) {
54
55 return -1;
56 }
57
58 return 0;
59 }
60
61 void *xdl_mmfile_first(mmfile_t *mmf, long *size)
62 {
63 *size = mmf->size;
64 return mmf->ptr;
65 }
66
67
68 long xdl_mmfile_size(mmfile_t *mmf)
69 {
70 return mmf->size;
71 }
72
73
74 int xdl_cha_init(chastore_t *cha, long isize, long icount) {
75
76 cha->head = cha->tail = NULL;
77 cha->isize = isize;
78 cha->nsize = icount * isize;
79 cha->ancur = cha->sncur = NULL;
80 cha->scurr = 0;
81
82 return 0;
83 }
84
85
86 void xdl_cha_free(chastore_t *cha) {
87 chanode_t *cur, *tmp;
88
89 for (cur = cha->head; (tmp = cur) != NULL;) {
90 cur = cur->next;
91 xdl_free(tmp);
92 }
93 }
94
95
96 void *xdl_cha_alloc(chastore_t *cha) {
97 chanode_t *ancur;
98 void *data;
99
100 if (!(ancur = cha->ancur) || ancur->icurr == cha->nsize) {
101 if (!(ancur = (chanode_t *) xdl_malloc(sizeof(chanode_t) + cha->nsize))) {
102
103 return NULL;
104 }
105 ancur->icurr = 0;
106 ancur->next = NULL;
107 if (cha->tail)
108 cha->tail->next = ancur;
109 if (!cha->head)
110 cha->head = ancur;
111 cha->tail = ancur;
112 cha->ancur = ancur;
113 }
114
115 data = (char *) ancur + sizeof(chanode_t) + ancur->icurr;
116 ancur->icurr += cha->isize;
117
118 return data;
119 }
120
121 long xdl_guess_lines(mmfile_t *mf, long sample) {
122 long nl = 0, size, tsize = 0;
123 char const *data, *cur, *top;
124
125 if ((cur = data = xdl_mmfile_first(mf, &size)) != NULL) {
126 for (top = data + size; nl < sample && cur < top; ) {
127 nl++;
128 if (!(cur = memchr(cur, '\n', top - cur)))
129 cur = top;
130 else
131 cur++;
132 }
133 tsize += (long) (cur - data);
134 }
135
136 if (nl && tsize)
137 nl = xdl_mmfile_size(mf) / (tsize / nl);
138
139 return nl + 1;
140 }
141
142 int xdl_blankline(const char *line, long size, long flags)
143 {
144 long i;
145
146 if (!(flags & XDF_WHITESPACE_FLAGS))
147 return (size <= 1);
148
149 for (i = 0; i < size && XDL_ISSPACE(line[i]); i++)
150 ;
151
152 return (i == size);
153 }
154
155 /*
156 * Have we eaten everything on the line, except for an optional
157 * CR at the very end?
158 */
159 static int ends_with_optional_cr(const char *l, long s, long i)
160 {
161 int complete = s && l[s-1] == '\n';
162
163 if (complete)
164 s--;
165 if (s == i)
166 return 1;
167 /* do not ignore CR at the end of an incomplete line */
168 if (complete && s == i + 1 && l[i] == '\r')
169 return 1;
170 return 0;
171 }
172
173 int xdl_recmatch(const char *l1, long s1, const char *l2, long s2, long flags)
174 {
175 int i1, i2;
176
177 if (s1 == s2 && !memcmp(l1, l2, s1))
178 return 1;
179 if (!(flags & XDF_WHITESPACE_FLAGS))
180 return 0;
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 * which in turn matches everything that matches with --ignore-cr-at-eol.
189 *
190 * Each flavor of ignoring needs different logic to skip whitespaces
191 * while we have both sides to compare.
192 */
193 if (flags & XDF_IGNORE_WHITESPACE) {
194 goto skip_ws;
195 while (i1 < s1 && i2 < s2) {
196 if (l1[i1++] != l2[i2++])
197 return 0;
198 skip_ws:
199 while (i1 < s1 && XDL_ISSPACE(l1[i1]))
200 i1++;
201 while (i2 < s2 && XDL_ISSPACE(l2[i2]))
202 i2++;
203 }
204 } else if (flags & XDF_IGNORE_WHITESPACE_CHANGE) {
205 while (i1 < s1 && i2 < s2) {
206 if (XDL_ISSPACE(l1[i1]) && XDL_ISSPACE(l2[i2])) {
207 /* Skip matching spaces and try again */
208 while (i1 < s1 && XDL_ISSPACE(l1[i1]))
209 i1++;
210 while (i2 < s2 && XDL_ISSPACE(l2[i2]))
211 i2++;
212 continue;
213 }
214 if (l1[i1++] != l2[i2++])
215 return 0;
216 }
217 } else if (flags & XDF_IGNORE_WHITESPACE_AT_EOL) {
218 while (i1 < s1 && i2 < s2 && l1[i1] == l2[i2]) {
219 i1++;
220 i2++;
221 }
222 } else if (flags & XDF_IGNORE_CR_AT_EOL) {
223 /* Find the first difference and see how the line ends */
224 while (i1 < s1 && i2 < s2 && l1[i1] == l2[i2]) {
225 i1++;
226 i2++;
227 }
228 return (ends_with_optional_cr(l1, s1, i1) &&
229 ends_with_optional_cr(l2, s2, i2));
230 }
231
232 /*
233 * After running out of one side, the remaining side must have
234 * nothing but whitespace for the lines to match. Note that
235 * ignore-whitespace-at-eol case may break out of the loop
236 * while there still are characters remaining on both lines.
237 */
238 if (i1 < s1) {
239 while (i1 < s1 && XDL_ISSPACE(l1[i1]))
240 i1++;
241 if (s1 != i1)
242 return 0;
243 }
244 if (i2 < s2) {
245 while (i2 < s2 && XDL_ISSPACE(l2[i2]))
246 i2++;
247 return (s2 == i2);
248 }
249 return 1;
250 }
251
252 static unsigned long xdl_hash_record_with_whitespace(char const **data,
253 char const *top, long flags) {
254 unsigned long ha = 5381;
255 char const *ptr = *data;
256 int cr_at_eol_only = (flags & XDF_WHITESPACE_FLAGS) == XDF_IGNORE_CR_AT_EOL;
257
258 for (; ptr < top && *ptr != '\n'; ptr++) {
259 if (cr_at_eol_only) {
260 /* do not ignore CR at the end of an incomplete line */
261 if (*ptr == '\r' &&
262 (ptr + 1 < top && ptr[1] == '\n'))
263 continue;
264 }
265 else if (XDL_ISSPACE(*ptr)) {
266 const char *ptr2 = ptr;
267 int at_eol;
268 while (ptr + 1 < top && XDL_ISSPACE(ptr[1])
269 && ptr[1] != '\n')
270 ptr++;
271 at_eol = (top <= ptr + 1 || ptr[1] == '\n');
272 if (flags & XDF_IGNORE_WHITESPACE)
273 ; /* already handled */
274 else if (flags & XDF_IGNORE_WHITESPACE_CHANGE
275 && !at_eol) {
276 ha += (ha << 5);
277 ha ^= (unsigned long) ' ';
278 }
279 else if (flags & XDF_IGNORE_WHITESPACE_AT_EOL
280 && !at_eol) {
281 while (ptr2 != ptr + 1) {
282 ha += (ha << 5);
283 ha ^= (unsigned long) *ptr2;
284 ptr2++;
285 }
286 }
287 continue;
288 }
289 ha += (ha << 5);
290 ha ^= (unsigned long) *ptr;
291 }
292 *data = ptr < top ? ptr + 1: ptr;
293
294 return ha;
295 }
296
297 unsigned long xdl_hash_record(char const **data, char const *top, long flags) {
298 unsigned long ha = 5381;
299 char const *ptr = *data;
300
301 if (flags & XDF_WHITESPACE_FLAGS)
302 return xdl_hash_record_with_whitespace(data, top, flags);
303
304 for (; ptr < top && *ptr != '\n'; ptr++) {
305 ha += (ha << 5);
306 ha ^= (unsigned long) *ptr;
307 }
308 *data = ptr < top ? ptr + 1: ptr;
309
310 return ha;
311 }
312
313 unsigned int xdl_hashbits(unsigned int size) {
314 unsigned int val = 1, bits = 0;
315
316 for (; val < size && bits < CHAR_BIT * sizeof(unsigned int); val <<= 1, bits++);
317 return bits ? bits: 1;
318 }
319
320
321 int xdl_num_out(char *out, long val) {
322 char *ptr, *str = out;
323 char buf[32];
324
325 ptr = buf + sizeof(buf) - 1;
326 *ptr = '\0';
327 if (val < 0) {
328 *--ptr = '-';
329 val = -val;
330 }
331 for (; val && ptr > buf; val /= 10)
332 *--ptr = "0123456789"[val % 10];
333 if (*ptr)
334 for (; *ptr; ptr++, str++)
335 *str = *ptr;
336 else
337 *str++ = '0';
338 *str = '\0';
339
340 return str - out;
341 }
342
343 static int xdl_format_hunk_hdr(long s1, long c1, long s2, long c2,
344 const char *func, long funclen,
345 xdemitcb_t *ecb) {
346 int nb = 0;
347 mmbuffer_t mb;
348 char buf[128];
349
350 memcpy(buf, "@@ -", 4);
351 nb += 4;
352
353 nb += xdl_num_out(buf + nb, c1 ? s1: s1 - 1);
354
355 if (c1 != 1) {
356 memcpy(buf + nb, ",", 1);
357 nb += 1;
358
359 nb += xdl_num_out(buf + nb, c1);
360 }
361
362 memcpy(buf + nb, " +", 2);
363 nb += 2;
364
365 nb += xdl_num_out(buf + nb, c2 ? s2: s2 - 1);
366
367 if (c2 != 1) {
368 memcpy(buf + nb, ",", 1);
369 nb += 1;
370
371 nb += xdl_num_out(buf + nb, c2);
372 }
373
374 memcpy(buf + nb, " @@", 3);
375 nb += 3;
376 if (func && funclen) {
377 buf[nb++] = ' ';
378 if (funclen > sizeof(buf) - nb - 1)
379 funclen = sizeof(buf) - nb - 1;
380 memcpy(buf + nb, func, funclen);
381 nb += funclen;
382 }
383 buf[nb++] = '\n';
384
385 mb.ptr = buf;
386 mb.size = nb;
387 if (ecb->out_line(ecb->priv, &mb, 1) < 0)
388 return -1;
389 return 0;
390 }
391
392 int xdl_emit_hunk_hdr(long s1, long c1, long s2, long c2,
393 const char *func, long funclen,
394 xdemitcb_t *ecb) {
395 if (!ecb->out_hunk)
396 return xdl_format_hunk_hdr(s1, c1, s2, c2, func, funclen, ecb);
397 if (ecb->out_hunk(ecb->priv,
398 c1 ? s1 : s1 - 1, c1,
399 c2 ? s2 : s2 - 1, c2,
400 func, funclen) < 0)
401 return -1;
402 return 0;
403 }
404
405 int xdl_fall_back_diff(xdfenv_t *diff_env, xpparam_t const *xpp,
406 int line1, int count1, int line2, int count2)
407 {
408 /*
409 * This probably does not work outside Git, since
410 * we have a very simple mmfile structure.
411 *
412 * Note: ideally, we would reuse the prepared environment, but
413 * the libxdiff interface does not (yet) allow for diffing only
414 * ranges of lines instead of the whole files.
415 */
416 mmfile_t subfile1, subfile2;
417 xdfenv_t env;
418
419 subfile1.ptr = (char *)diff_env->xdf1.recs[line1 - 1]->ptr;
420 subfile1.size = diff_env->xdf1.recs[line1 + count1 - 2]->ptr +
421 diff_env->xdf1.recs[line1 + count1 - 2]->size - subfile1.ptr;
422 subfile2.ptr = (char *)diff_env->xdf2.recs[line2 - 1]->ptr;
423 subfile2.size = diff_env->xdf2.recs[line2 + count2 - 2]->ptr +
424 diff_env->xdf2.recs[line2 + count2 - 2]->size - subfile2.ptr;
425 if (xdl_do_diff(&subfile1, &subfile2, xpp, &env) < 0)
426 return -1;
427
428 memcpy(diff_env->xdf1.rchg + line1 - 1, env.xdf1.rchg, count1);
429 memcpy(diff_env->xdf2.rchg + line2 - 1, env.xdf2.rchg, count2);
430
431 xdl_free_env(&env);
432
433 return 0;
434 }