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 <limits.h>
  24 #include <assert.h>
  25 #include "xinclude.h"
  26
  27
  28
  29
  30 long xdl_bogosqrt(long n) {
  31         long i;
  32
  33         /*
  34          * Classical integer square root approximation using shifts.
  35          */
  36         for (i = 1; n > 0; n >>= 2)
  37                 i <<= 1;
  38
  39         return i;
  40 }
  41
  42
  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];
  47
  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++;
  56         }
  57         if (ecb->outf(ecb->priv, mb, i) < 0) {
  58
  59                 return -1;
  60         }
  61
  62         return 0;
  63 }
  64
  65 void *xdl_mmfile_first(mmfile_t *mmf, long *size)
  66 {
  67         *size = mmf->size;
  68         return mmf->ptr;
  69 }
  70
  71
  72 long xdl_mmfile_size(mmfile_t *mmf)
  73 {
  74         return mmf->size;
  75 }
  76
  77
  78 int xdl_cha_init(chastore_t *cha, long isize, long icount) {
  79
  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;
  85
  86         return 0;
  87 }
  88
  89
  90 void xdl_cha_free(chastore_t *cha) {
  91         chanode_t *cur, *tmp;
  92
  93         for (cur = cha->head; (tmp = cur) != NULL;) {
  94                 cur = cur->next;
  95                 xdl_free(tmp);
  96         }
  97 }
  98
  99
 100 void *xdl_cha_alloc(chastore_t *cha) {
 101         chanode_t *ancur;
 102         void *data;
 103
 104         if (!(ancur = cha->ancur) || ancur->icurr == cha->nsize) {
 105                 if (!(ancur = (chanode_t *) xdl_malloc(sizeof(chanode_t) + cha->nsize))) {
 106
 107                         return NULL;
 108                 }
 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;
 117         }
 118
 119         data = (char *) ancur + sizeof(chanode_t) + ancur->icurr;
 120         ancur->icurr += cha->isize;
 121
 122         return data;
 123 }
 124
 125 long xdl_guess_lines(mmfile_t *mf, long sample) {
 126         long nl = 0, size, tsize = 0;
 127         char const *data, *cur, *top;
 128
 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++;
 136                 }
 137                 tsize += (long) (cur - data);
 138         }
 139
 140         if (nl && tsize)
 141                 nl = xdl_mmfile_size(mf) / (tsize / nl);
 142
 143         return nl + 1;
 144 }
 145
 146 int xdl_blankline(const char *line, long size, long flags)
 147 {
 148         long i;
 149
 150         if (!(flags & XDF_WHITESPACE_FLAGS))
 151                 return (size <= 1);
 152
 153         for (i = 0; i < size && XDL_ISSPACE(line[i]); i++)
 154                 ;
 155
 156         return (i == size);
 157 }
 158
 159 /*
 160  * Have we eaten everything on the line, except for an optional
 161  * CR at the very end?
 162  */
 163 static int ends_with_optional_cr(const char *l, long s, long i)
 164 {
 165         int complete = s && l[s-1] == '\n';
 166
 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;
 175 }
 176
 177 int xdl_recmatch(const char *l1, long s1, const char *l2, long s2, long flags)
 178 {
 179         int i1, i2;
 180
 181         if (s1 == s2 && !memcmp(l1, l2, s1))
 182                 return 1;
 183         if (!(flags & XDF_WHITESPACE_FLAGS))
 184                 return 0;
 185
 186         i1 = 0;
 187         i2 = 0;
 188
 189         /*
 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.
 193          *
 194          * Each flavor of ignoring needs different logic to skip whitespaces
 195          * while we have both sides to compare.
 196          */
 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++;
 207                 }
 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;
 217                         }
 218                         if (l1[i1++] != l2[i2++])
 219                                 return 0;
 220                 }
 221         } else if (flags & XDF_IGNORE_WHITESPACE_AT_EOL) {
 222                 while (i1 < s1 && i2 < s2 && l1[i1] == l2[i2]) {
 223                         i1++;
 224                         i2++;
 225                 }
 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++;
 231                 }
 232                 return (ends_with_optional_cr(l1, s1, i1) &&
 233                         ends_with_optional_cr(l2, s2, i2));
 234         }
 235
 236         /*
 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.
 241          */
 242         if (i1 < s1) {
 243                 while (i1 < s1 && XDL_ISSPACE(l1[i1]))
 244                         i1++;
 245                 if (s1 != i1)
 246                         return 0;
 247         }
 248         if (i2 < s2) {
 249                 while (i2 < s2 && XDL_ISSPACE(l2[i2]))
 250                         i2++;
 251                 return (s2 == i2);
 252         }
 253         return 1;
 254 }
 255
 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;
 261
 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;
 268                 }
 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) ' ';
 282                         }
 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++;
 289                                 }
 290                         }
 291                         continue;
 292                 }
 293                 ha += (ha << 5);
 294                 ha ^= (unsigned long) *ptr;
 295         }
 296         *data = ptr < top ? ptr + 1: ptr;
 297
 298         return ha;
 299 }
 300
 301 unsigned long xdl_hash_record(char const **data, char const *top, long flags) {
 302         unsigned long ha = 5381;
 303         char const *ptr = *data;
 304
 305         if (flags & XDF_WHITESPACE_FLAGS)
 306                 return xdl_hash_record_with_whitespace(data, top, flags);
 307
 308         for (; ptr < top && *ptr != '\n'; ptr++) {
 309                 ha += (ha << 5);
 310                 ha ^= (unsigned long) *ptr;
 311         }
 312         *data = ptr < top ? ptr + 1: ptr;
 313
 314         return ha;
 315 }
 316
 317 unsigned int xdl_hashbits(unsigned int size) {
 318         unsigned int val = 1, bits = 0;
 319
 320         for (; val < size && bits < CHAR_BIT * sizeof(unsigned int); val <<= 1, bits++);
 321         return bits ? bits: 1;
 322 }
 323
 324
 325 int xdl_num_out(char *out, long val) {
 326         char *ptr, *str = out;
 327         char buf[32];
 328
 329         ptr = buf + sizeof(buf) - 1;
 330         *ptr = '\0';
 331         if (val < 0) {
 332                 *--ptr = '-';
 333                 val = -val;
 334         }
 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';
 343
 344         return str - out;
 345 }
 346
 347 int xdl_emit_hunk_hdr(long s1, long c1, long s2, long c2,
 348                       const char *func, long funclen, xdemitcb_t *ecb) {
 349         int nb = 0;
 350         mmbuffer_t mb;
 351         char buf[128];
 352
 353         memcpy(buf, "@@ -", 4);
 354         nb += 4;
 355
 356         nb += xdl_num_out(buf + nb, c1 ? s1: s1 - 1);
 357
 358         if (c1 != 1) {
 359                 memcpy(buf + nb, ",", 1);
 360                 nb += 1;
 361
 362                 nb += xdl_num_out(buf + nb, c1);
 363         }
 364
 365         memcpy(buf + nb, " +", 2);
 366         nb += 2;
 367
 368         nb += xdl_num_out(buf + nb, c2 ? s2: s2 - 1);
 369
 370         if (c2 != 1) {
 371                 memcpy(buf + nb, ",", 1);
 372                 nb += 1;
 373
 374                 nb += xdl_num_out(buf + nb, c2);
 375         }
 376
 377         memcpy(buf + nb, " @@", 3);
 378         nb += 3;
 379         if (func && funclen) {
 380                 buf[nb++] = ' ';
 381                 if (funclen > sizeof(buf) - nb - 1)
 382                         funclen = sizeof(buf) - nb - 1;
 383                 memcpy(buf + nb, func, funclen);
 384                 nb += funclen;
 385         }
 386         buf[nb++] = '\n';
 387
 388         mb.ptr = buf;
 389         mb.size = nb;
 390         if (ecb->outf(ecb->priv, &mb, 1) < 0)
 391                 return -1;
 392
 393         return 0;
 394 }
 395
 396 int xdl_fall_back_diff(xdfenv_t *diff_env, xpparam_t const *xpp,
 397                 int line1, int count1, int line2, int count2)
 398 {
 399         /*
 400          * This probably does not work outside Git, since
 401          * we have a very simple mmfile structure.
 402          *
 403          * Note: ideally, we would reuse the prepared environment, but
 404          * the libxdiff interface does not (yet) allow for diffing only
 405          * ranges of lines instead of the whole files.
 406          */
 407         mmfile_t subfile1, subfile2;
 408         xdfenv_t env;
 409
 410         subfile1.ptr = (char *)diff_env->xdf1.recs[line1 - 1]->ptr;
 411         subfile1.size = diff_env->xdf1.recs[line1 + count1 - 2]->ptr +
 412                 diff_env->xdf1.recs[line1 + count1 - 2]->size - subfile1.ptr;
 413         subfile2.ptr = (char *)diff_env->xdf2.recs[line2 - 1]->ptr;
 414         subfile2.size = diff_env->xdf2.recs[line2 + count2 - 2]->ptr +
 415                 diff_env->xdf2.recs[line2 + count2 - 2]->size - subfile2.ptr;
 416         if (xdl_do_diff(&subfile1, &subfile2, xpp, &env) < 0)
 417                 return -1;
 418
 419         memcpy(diff_env->xdf1.rchg + line1 - 1, env.xdf1.rchg, count1);
 420         memcpy(diff_env->xdf2.rchg + line2 - 1, env.xdf2.rchg, count2);
 421
 422         xdl_free_env(&env);
 423
 424         return 0;
 425 }