src/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
  27
  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
  41 int xdl_emit_diffrec(char const *rec, long size, char const *pre, long psize,
  42                      xdemitcb_t *ecb) {
  43         int i = 2;
  44         mmbuffer_t mb[3];
  45
  46         mb[0].ptr = (char *) pre;
  47         mb[0].size = psize;
  48         mb[1].ptr = (char *) rec;
  49         mb[1].size = size;
  50         if (size > 0 && rec[size - 1] != '\n') {
  51                 mb[2].ptr = (char *) "\n\\ No newline at end of file\n";
  52                 mb[2].size = strlen(mb[2].ptr);
  53                 i++;
  54         }
  55         if (ecb->outf(ecb->priv, mb, i) < 0) {
  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
  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 long xdl_guess_lines(mmfile_t *mf, long sample) {
 124         long nl = 0, size, tsize = 0;
 125         char const *data, *cur, *top;
 126
 127         if ((cur = data = xdl_mmfile_first(mf, &size)) != NULL) {
 128                 for (top = data + size; nl < sample && cur < top; ) {
 129                         nl++;
 130                         if (!(cur = memchr(cur, '\n', top - cur)))
 131                                 cur = top;
 132                         else
 133                                 cur++;
 134                 }
 135                 tsize += (long) (cur - data);
 136         }
 137
 138         if (nl && tsize)
 139                 nl = xdl_mmfile_size(mf) / (tsize / nl);
 140
 141         return nl + 1;
 142 }
 143
 144 int xdl_blankline(const char *line, long size, long flags)
 145 {
 146         long i;
 147
 148         if (!(flags & XDF_WHITESPACE_FLAGS))
 149                 return (size <= 1);
 150
 151         for (i = 0; i < size && XDL_ISSPACE(line[i]); i++)
 152                 ;
 153
 154         return (i == size);
 155 }
 156
 157 /*
 158  * Have we eaten everything on the line, except for an optional
 159  * CR at the very end?
 160  */
 161 static int ends_with_optional_cr(const char *l, long s, long i)
 162 {
 163         int complete = s && l[s-1] == '\n';
 164
 165         if (complete)
 166                 s--;
 167         if (s == i)
 168                 return 1;
 169         /* do not ignore CR at the end of an incomplete line */
 170         if (complete && s == i + 1 && l[i] == '\r')
 171                 return 1;
 172         return 0;
 173 }
 174
 175 int xdl_recmatch(const char *l1, long s1, const char *l2, long s2, long flags)
 176 {
 177         int i1, i2;
 178
 179         if (s1 == s2 && !memcmp(l1, l2, s1))
 180                 return 1;
 181         if (!(flags & XDF_WHITESPACE_FLAGS))
 182                 return 0;
 183
 184         i1 = 0;
 185         i2 = 0;
 186
 187         /*
 188          * -w matches everything that matches with -b, and -b in turn
 189          * matches everything that matches with --ignore-space-at-eol,
 190          * which in turn matches everything that matches with --ignore-cr-at-eol.
 191          *
 192          * Each flavor of ignoring needs different logic to skip whitespaces
 193          * while we have both sides to compare.
 194          */
 195         if (flags & XDF_IGNORE_WHITESPACE) {
 196                 goto skip_ws;
 197                 while (i1 < s1 && i2 < s2) {
 198                         if (l1[i1++] != l2[i2++])
 199                                 return 0;
 200                 skip_ws:
 201                         while (i1 < s1 && XDL_ISSPACE(l1[i1]))
 202                                 i1++;
 203                         while (i2 < s2 && XDL_ISSPACE(l2[i2]))
 204                                 i2++;
 205                 }
 206         } else if (flags & XDF_IGNORE_WHITESPACE_CHANGE) {
 207                 while (i1 < s1 && i2 < s2) {
 208                         if (XDL_ISSPACE(l1[i1]) && XDL_ISSPACE(l2[i2])) {
 209                                 /* Skip matching spaces and try again */
 210                                 while (i1 < s1 && XDL_ISSPACE(l1[i1]))
 211                                         i1++;
 212                                 while (i2 < s2 && XDL_ISSPACE(l2[i2]))
 213                                         i2++;
 214                                 continue;
 215                         }
 216                         if (l1[i1++] != l2[i2++])
 217                                 return 0;
 218                 }
 219         } else if (flags & XDF_IGNORE_WHITESPACE_AT_EOL) {
 220                 while (i1 < s1 && i2 < s2 && l1[i1] == l2[i2]) {
 221                         i1++;
 222                         i2++;
 223                 }
 224         } else if (flags & XDF_IGNORE_CR_AT_EOL) {
 225                 /* Find the first difference and see how the line ends */
 226                 while (i1 < s1 && i2 < s2 && l1[i1] == l2[i2]) {
 227                         i1++;
 228                         i2++;
 229                 }
 230                 return (ends_with_optional_cr(l1, s1, i1) &&
 231                         ends_with_optional_cr(l2, s2, i2));
 232         }
 233
 234         /*
 235          * After running out of one side, the remaining side must have
 236          * nothing but whitespace for the lines to match.  Note that
 237          * ignore-whitespace-at-eol case may break out of the loop
 238          * while there still are characters remaining on both lines.
 239          */
 240         if (i1 < s1) {
 241                 while (i1 < s1 && XDL_ISSPACE(l1[i1]))
 242                         i1++;
 243                 if (s1 != i1)
 244                         return 0;
 245         }
 246         if (i2 < s2) {
 247                 while (i2 < s2 && XDL_ISSPACE(l2[i2]))
 248                         i2++;
 249                 return (s2 == i2);
 250         }
 251         return 1;
 252 }
 253
 254 static unsigned long xdl_hash_record_with_whitespace(char const **data,
 255                 char const *top, long flags) {
 256         unsigned long ha = 5381;
 257         char const *ptr = *data;
 258         int cr_at_eol_only = (flags & XDF_WHITESPACE_FLAGS) == XDF_IGNORE_CR_AT_EOL;
 259
 260         for (; ptr < top && *ptr != '\n'; ptr++) {
 261                 if (cr_at_eol_only) {
 262                         /* do not ignore CR at the end of an incomplete line */
 263                         if (*ptr == '\r' &&
 264                             (ptr + 1 < top && ptr[1] == '\n'))
 265                                 continue;
 266                 }
 267                 else if (XDL_ISSPACE(*ptr)) {
 268                         const char *ptr2 = ptr;
 269                         int at_eol;
 270                         while (ptr + 1 < top && XDL_ISSPACE(ptr[1])
 271                                         && ptr[1] != '\n')
 272                                 ptr++;
 273                         at_eol = (top <= ptr + 1 || ptr[1] == '\n');
 274                         if (flags & XDF_IGNORE_WHITESPACE)
 275                                 ; /* already handled */
 276                         else if (flags & XDF_IGNORE_WHITESPACE_CHANGE
 277                                  && !at_eol) {
 278                                 ha += (ha << 5);
 279                                 ha ^= (unsigned long) ' ';
 280                         }
 281                         else if (flags & XDF_IGNORE_WHITESPACE_AT_EOL
 282                                  && !at_eol) {
 283                                 while (ptr2 != ptr + 1) {
 284                                         ha += (ha << 5);
 285                                         ha ^= (unsigned long) *ptr2;
 286                                         ptr2++;
 287                                 }
 288                         }
 289                         continue;
 290                 }
 291                 ha += (ha << 5);
 292                 ha ^= (unsigned long) *ptr;
 293         }
 294         *data = ptr < top ? ptr + 1: ptr;
 295
 296         return ha;
 297 }
 298
 299 unsigned long xdl_hash_record(char const **data, char const *top, long flags) {
 300         unsigned long ha = 5381;
 301         char const *ptr = *data;
 302
 303         if (flags & XDF_WHITESPACE_FLAGS)
 304                 return xdl_hash_record_with_whitespace(data, top, flags);
 305
 306         for (; ptr < top && *ptr != '\n'; ptr++) {
 307                 ha += (ha << 5);
 308                 ha ^= (unsigned long) *ptr;
 309         }
 310         *data = ptr < top ? ptr + 1: ptr;
 311
 312         return ha;
 313 }
 314
 315 unsigned int xdl_hashbits(unsigned int size) {
 316         unsigned int val = 1, bits = 0;
 317
 318         for (; val < size && bits < CHAR_BIT * sizeof(unsigned int); val <<= 1, bits++);
 319         return bits ? bits: 1;
 320 }
 321
 322
 323 int xdl_num_out(char *out, long val) {
 324         char *ptr, *str = out;
 325         char buf[32];
 326
 327         ptr = buf + sizeof(buf) - 1;
 328         *ptr = '\0';
 329         if (val < 0) {
 330                 *--ptr = '-';
 331                 val = -val;
 332         }
 333         for (; val && ptr > buf; val /= 10)
 334                 *--ptr = "0123456789"[val % 10];
 335         if (*ptr)
 336                 for (; *ptr; ptr++, str++)
 337                         *str = *ptr;
 338         else
 339                 *str++ = '0';
 340         *str = '\0';
 341
 342         return str - out;
 343 }
 344
 345 int xdl_emit_hunk_hdr(long s1, long c1, long s2, long c2,
 346                       const char *func, long funclen, xdemitcb_t *ecb) {
 347         int nb = 0;
 348         mmbuffer_t mb;
 349         char buf[128];
 350
 351         memcpy(buf, "@@ -", 4);
 352         nb += 4;
 353
 354         nb += xdl_num_out(buf + nb, c1 ? s1: s1 - 1);
 355
 356         if (c1 != 1) {
 357                 memcpy(buf + nb, ",", 1);
 358                 nb += 1;
 359
 360                 nb += xdl_num_out(buf + nb, c1);
 361         }
 362
 363         memcpy(buf + nb, " +", 2);
 364         nb += 2;
 365
 366         nb += xdl_num_out(buf + nb, c2 ? s2: s2 - 1);
 367
 368         if (c2 != 1) {
 369                 memcpy(buf + nb, ",", 1);
 370                 nb += 1;
 371
 372                 nb += xdl_num_out(buf + nb, c2);
 373         }
 374
 375         memcpy(buf + nb, " @@", 3);
 376         nb += 3;
 377         if (func && funclen) {
 378                 buf[nb++] = ' ';
 379                 if (funclen > (long)(sizeof(buf) - nb - 1))
 380                         funclen = sizeof(buf) - nb - 1;
 381                 memcpy(buf + nb, func, funclen);
 382                 nb += funclen;
 383         }
 384         buf[nb++] = '\n';
 385
 386         mb.ptr = buf;
 387         mb.size = nb;
 388         if (ecb->outf(ecb->priv, &mb, 1) < 0)
 389                 return -1;
 390
 391         return 0;
 392 }
 393
 394 int xdl_fall_back_diff(xdfenv_t *diff_env, xpparam_t const *xpp,
 395                 int line1, int count1, int line2, int count2)
 396 {
 397         /*
 398          * This probably does not work outside Git, since
 399          * we have a very simple mmfile structure.
 400          *
 401          * Note: ideally, we would reuse the prepared environment, but
 402          * the libxdiff interface does not (yet) allow for diffing only
 403          * ranges of lines instead of the whole files.
 404          */
 405         mmfile_t subfile1, subfile2;
 406         xdfenv_t env;
 407
 408         subfile1.ptr = (char *)diff_env->xdf1.recs[line1 - 1]->ptr;
 409         subfile1.size = diff_env->xdf1.recs[line1 + count1 - 2]->ptr +
 410                 diff_env->xdf1.recs[line1 + count1 - 2]->size - subfile1.ptr;
 411         subfile2.ptr = (char *)diff_env->xdf2.recs[line2 - 1]->ptr;
 412         subfile2.size = diff_env->xdf2.recs[line2 + count2 - 2]->ptr +
 413                 diff_env->xdf2.recs[line2 + count2 - 2]->size - subfile2.ptr;
 414         if (xdl_do_diff(&subfile1, &subfile2, xpp, &env) < 0)
 415                 return -1;
 416
 417         memcpy(diff_env->xdf1.rchg + line1 - 1, env.xdf1.rchg, count1);
 418         memcpy(diff_env->xdf2.rchg + line2 - 1, env.xdf2.rchg, count2);
 419
 420         xdl_free_env(&env);
 421
 422         return 0;
 423 }