Documentation: explain the meaning of "-g" in git-describe output
[git/gitweb.git] / xdiff / xutils.c
blobbc12f298953a4e72b323f73607278028ec4a2805
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 "xinclude.h"
27 #define XDL_GUESS_NLINES 256
32 long xdl_bogosqrt(long n) {
33 long i;
36 * Classical integer square root approximation using shifts.
38 for (i = 1; n > 0; n >>= 2)
39 i <<= 1;
41 return i;
45 int xdl_emit_diffrec(char const *rec, long size, char const *pre, long psize,
46 xdemitcb_t *ecb) {
47 int i = 2;
48 mmbuffer_t mb[3];
50 mb[0].ptr = (char *) pre;
51 mb[0].size = psize;
52 mb[1].ptr = (char *) rec;
53 mb[1].size = size;
54 if (size > 0 && rec[size - 1] != '\n') {
55 mb[2].ptr = (char *) "\n\\ No newline at end of file\n";
56 mb[2].size = strlen(mb[2].ptr);
57 i++;
59 if (ecb->outf(ecb->priv, mb, i) < 0) {
61 return -1;
64 return 0;
67 void *xdl_mmfile_first(mmfile_t *mmf, long *size)
69 *size = mmf->size;
70 return mmf->ptr;
74 void *xdl_mmfile_next(mmfile_t *mmf, long *size)
76 return NULL;
80 long xdl_mmfile_size(mmfile_t *mmf)
82 return mmf->size;
86 int xdl_cha_init(chastore_t *cha, long isize, long icount) {
88 cha->head = cha->tail = NULL;
89 cha->isize = isize;
90 cha->nsize = icount * isize;
91 cha->ancur = cha->sncur = NULL;
92 cha->scurr = 0;
94 return 0;
98 void xdl_cha_free(chastore_t *cha) {
99 chanode_t *cur, *tmp;
101 for (cur = cha->head; (tmp = cur) != NULL;) {
102 cur = cur->next;
103 xdl_free(tmp);
108 void *xdl_cha_alloc(chastore_t *cha) {
109 chanode_t *ancur;
110 void *data;
112 if (!(ancur = cha->ancur) || ancur->icurr == cha->nsize) {
113 if (!(ancur = (chanode_t *) xdl_malloc(sizeof(chanode_t) + cha->nsize))) {
115 return NULL;
117 ancur->icurr = 0;
118 ancur->next = NULL;
119 if (cha->tail)
120 cha->tail->next = ancur;
121 if (!cha->head)
122 cha->head = ancur;
123 cha->tail = ancur;
124 cha->ancur = ancur;
127 data = (char *) ancur + sizeof(chanode_t) + ancur->icurr;
128 ancur->icurr += cha->isize;
130 return data;
134 void *xdl_cha_first(chastore_t *cha) {
135 chanode_t *sncur;
137 if (!(cha->sncur = sncur = cha->head))
138 return NULL;
140 cha->scurr = 0;
142 return (char *) sncur + sizeof(chanode_t) + cha->scurr;
146 void *xdl_cha_next(chastore_t *cha) {
147 chanode_t *sncur;
149 if (!(sncur = cha->sncur))
150 return NULL;
151 cha->scurr += cha->isize;
152 if (cha->scurr == sncur->icurr) {
153 if (!(sncur = cha->sncur = sncur->next))
154 return NULL;
155 cha->scurr = 0;
158 return (char *) sncur + sizeof(chanode_t) + cha->scurr;
162 long xdl_guess_lines(mmfile_t *mf) {
163 long nl = 0, size, tsize = 0;
164 char const *data, *cur, *top;
166 if ((cur = data = xdl_mmfile_first(mf, &size)) != NULL) {
167 for (top = data + size; nl < XDL_GUESS_NLINES;) {
168 if (cur >= top) {
169 tsize += (long) (cur - data);
170 if (!(cur = data = xdl_mmfile_next(mf, &size)))
171 break;
172 top = data + size;
174 nl++;
175 if (!(cur = memchr(cur, '\n', top - cur)))
176 cur = top;
177 else
178 cur++;
180 tsize += (long) (cur - data);
183 if (nl && tsize)
184 nl = xdl_mmfile_size(mf) / (tsize / nl);
186 return nl + 1;
189 int xdl_recmatch(const char *l1, long s1, const char *l2, long s2, long flags)
191 int i1, i2;
193 if (!(flags & XDF_WHITESPACE_FLAGS))
194 return s1 == s2 && !memcmp(l1, l2, s1);
196 i1 = 0;
197 i2 = 0;
200 * -w matches everything that matches with -b, and -b in turn
201 * matches everything that matches with --ignore-space-at-eol.
203 * Each flavor of ignoring needs different logic to skip whitespaces
204 * while we have both sides to compare.
206 if (flags & XDF_IGNORE_WHITESPACE) {
207 goto skip_ws;
208 while (i1 < s1 && i2 < s2) {
209 if (l1[i1++] != l2[i2++])
210 return 0;
211 skip_ws:
212 while (i1 < s1 && isspace(l1[i1]))
213 i1++;
214 while (i2 < s2 && isspace(l2[i2]))
215 i2++;
217 } else if (flags & XDF_IGNORE_WHITESPACE_CHANGE) {
218 while (i1 < s1 && i2 < s2) {
219 if (isspace(l1[i1]) && isspace(l2[i2])) {
220 /* Skip matching spaces and try again */
221 while (i1 < s1 && isspace(l1[i1]))
222 i1++;
223 while (i2 < s2 && isspace(l2[i2]))
224 i2++;
225 continue;
227 if (l1[i1++] != l2[i2++])
228 return 0;
230 } else if (flags & XDF_IGNORE_WHITESPACE_AT_EOL) {
231 while (i1 < s1 && i2 < s2 && l1[i1++] == l2[i2++])
232 ; /* keep going */
236 * After running out of one side, the remaining side must have
237 * nothing but whitespace for the lines to match. Note that
238 * ignore-whitespace-at-eol case may break out of the loop
239 * while there still are characters remaining on both lines.
241 if (i1 < s1) {
242 while (i1 < s1 && isspace(l1[i1]))
243 i1++;
244 if (s1 != i1)
245 return 0;
247 if (i2 < s2) {
248 while (i2 < s2 && isspace(l2[i2]))
249 i2++;
250 return (s2 == i2);
252 return 1;
255 static unsigned long xdl_hash_record_with_whitespace(char const **data,
256 char const *top, long flags) {
257 unsigned long ha = 5381;
258 char const *ptr = *data;
260 for (; ptr < top && *ptr != '\n'; ptr++) {
261 if (isspace(*ptr)) {
262 const char *ptr2 = ptr;
263 int at_eol;
264 while (ptr + 1 < top && isspace(ptr[1])
265 && ptr[1] != '\n')
266 ptr++;
267 at_eol = (top <= ptr + 1 || ptr[1] == '\n');
268 if (flags & XDF_IGNORE_WHITESPACE)
269 ; /* already handled */
270 else if (flags & XDF_IGNORE_WHITESPACE_CHANGE
271 && !at_eol) {
272 ha += (ha << 5);
273 ha ^= (unsigned long) ' ';
275 else if (flags & XDF_IGNORE_WHITESPACE_AT_EOL
276 && !at_eol) {
277 while (ptr2 != ptr + 1) {
278 ha += (ha << 5);
279 ha ^= (unsigned long) *ptr2;
280 ptr2++;
283 continue;
285 ha += (ha << 5);
286 ha ^= (unsigned long) *ptr;
288 *data = ptr < top ? ptr + 1: ptr;
290 return ha;
294 unsigned long xdl_hash_record(char const **data, char const *top, long flags) {
295 unsigned long ha = 5381;
296 char const *ptr = *data;
298 if (flags & XDF_WHITESPACE_FLAGS)
299 return xdl_hash_record_with_whitespace(data, top, flags);
301 for (; ptr < top && *ptr != '\n'; ptr++) {
302 ha += (ha << 5);
303 ha ^= (unsigned long) *ptr;
305 *data = ptr < top ? ptr + 1: ptr;
307 return ha;
311 unsigned int xdl_hashbits(unsigned int size) {
312 unsigned int val = 1, bits = 0;
314 for (; val < size && bits < CHAR_BIT * sizeof(unsigned int); val <<= 1, bits++);
315 return bits ? bits: 1;
319 int xdl_num_out(char *out, long val) {
320 char *ptr, *str = out;
321 char buf[32];
323 ptr = buf + sizeof(buf) - 1;
324 *ptr = '\0';
325 if (val < 0) {
326 *--ptr = '-';
327 val = -val;
329 for (; val && ptr > buf; val /= 10)
330 *--ptr = "0123456789"[val % 10];
331 if (*ptr)
332 for (; *ptr; ptr++, str++)
333 *str = *ptr;
334 else
335 *str++ = '0';
336 *str = '\0';
338 return str - out;
342 long xdl_atol(char const *str, char const **next) {
343 long val, base;
344 char const *top;
346 for (top = str; XDL_ISDIGIT(*top); top++);
347 if (next)
348 *next = top;
349 for (val = 0, base = 1, top--; top >= str; top--, base *= 10)
350 val += base * (long)(*top - '0');
351 return val;
355 int xdl_emit_hunk_hdr(long s1, long c1, long s2, long c2,
356 const char *func, long funclen, xdemitcb_t *ecb) {
357 int nb = 0;
358 mmbuffer_t mb;
359 char buf[128];
361 memcpy(buf, "@@ -", 4);
362 nb += 4;
364 nb += xdl_num_out(buf + nb, c1 ? s1: s1 - 1);
366 if (c1 != 1) {
367 memcpy(buf + nb, ",", 1);
368 nb += 1;
370 nb += xdl_num_out(buf + nb, c1);
373 memcpy(buf + nb, " +", 2);
374 nb += 2;
376 nb += xdl_num_out(buf + nb, c2 ? s2: s2 - 1);
378 if (c2 != 1) {
379 memcpy(buf + nb, ",", 1);
380 nb += 1;
382 nb += xdl_num_out(buf + nb, c2);
385 memcpy(buf + nb, " @@", 3);
386 nb += 3;
387 if (func && funclen) {
388 buf[nb++] = ' ';
389 if (funclen > sizeof(buf) - nb - 1)
390 funclen = sizeof(buf) - nb - 1;
391 memcpy(buf + nb, func, funclen);
392 nb += funclen;
394 buf[nb++] = '\n';
396 mb.ptr = buf;
397 mb.size = nb;
398 if (ecb->outf(ecb->priv, &mb, 1) < 0)
399 return -1;
401 return 0;