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, write to the Free Software
  17  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  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 void *xdl_mmfile_next(mmfile_t *mmf, long *size)
  71 {
  72         return NULL;
  73 }
  74
  75
  76 long xdl_mmfile_size(mmfile_t *mmf)
  77 {
  78         return mmf->size;
  79 }
  80
  81
  82 int xdl_cha_init(chastore_t *cha, long isize, long icount) {
  83
  84         cha->head = cha->tail = NULL;
  85         cha->isize = isize;
  86         cha->nsize = icount * isize;
  87         cha->ancur = cha->sncur = NULL;
  88         cha->scurr = 0;
  89
  90         return 0;
  91 }
  92
  93
  94 void xdl_cha_free(chastore_t *cha) {
  95         chanode_t *cur, *tmp;
  96
  97         for (cur = cha->head; (tmp = cur) != NULL;) {
  98                 cur = cur->next;
  99                 xdl_free(tmp);
 100         }
 101 }
 102
 103
 104 void *xdl_cha_alloc(chastore_t *cha) {
 105         chanode_t *ancur;
 106         void *data;
 107
 108         if (!(ancur = cha->ancur) || ancur->icurr == cha->nsize) {
 109                 if (!(ancur = (chanode_t *) xdl_malloc(sizeof(chanode_t) + cha->nsize))) {
 110
 111                         return NULL;
 112                 }
 113                 ancur->icurr = 0;
 114                 ancur->next = NULL;
 115                 if (cha->tail)
 116                         cha->tail->next = ancur;
 117                 if (!cha->head)
 118                         cha->head = ancur;
 119                 cha->tail = ancur;
 120                 cha->ancur = ancur;
 121         }
 122
 123         data = (char *) ancur + sizeof(chanode_t) + ancur->icurr;
 124         ancur->icurr += cha->isize;
 125
 126         return data;
 127 }
 128
 129
 130 void *xdl_cha_first(chastore_t *cha) {
 131         chanode_t *sncur;
 132
 133         if (!(cha->sncur = sncur = cha->head))
 134                 return NULL;
 135
 136         cha->scurr = 0;
 137
 138         return (char *) sncur + sizeof(chanode_t) + cha->scurr;
 139 }
 140
 141
 142 void *xdl_cha_next(chastore_t *cha) {
 143         chanode_t *sncur;
 144
 145         if (!(sncur = cha->sncur))
 146                 return NULL;
 147         cha->scurr += cha->isize;
 148         if (cha->scurr == sncur->icurr) {
 149                 if (!(sncur = cha->sncur = sncur->next))
 150                         return NULL;
 151                 cha->scurr = 0;
 152         }
 153
 154         return (char *) sncur + sizeof(chanode_t) + cha->scurr;
 155 }
 156
 157
 158 long xdl_guess_lines(mmfile_t *mf, long sample) {
 159         long nl = 0, size, tsize = 0;
 160         char const *data, *cur, *top;
 161
 162         if ((cur = data = xdl_mmfile_first(mf, &size)) != NULL) {
 163                 for (top = data + size; nl < sample;) {
 164                         if (cur >= top) {
 165                                 tsize += (long) (cur - data);
 166                                 if (!(cur = data = xdl_mmfile_next(mf, &size)))
 167                                         break;
 168                                 top = data + size;
 169                         }
 170                         nl++;
 171                         if (!(cur = memchr(cur, '\n', top - cur)))
 172                                 cur = top;
 173                         else
 174                                 cur++;
 175                 }
 176                 tsize += (long) (cur - data);
 177         }
 178
 179         if (nl && tsize)
 180                 nl = xdl_mmfile_size(mf) / (tsize / nl);
 181
 182         return nl + 1;
 183 }
 184
 185 int xdl_recmatch(const char *l1, long s1, const char *l2, long s2, long flags)
 186 {
 187         int i1, i2;
 188
 189         if (s1 == s2 && !memcmp(l1, l2, s1))
 190                 return 1;
 191         if (!(flags & XDF_WHITESPACE_FLAGS))
 192                 return 0;
 193
 194         i1 = 0;
 195         i2 = 0;
 196
 197         /*
 198          * -w matches everything that matches with -b, and -b in turn
 199          * matches everything that matches with --ignore-space-at-eol.
 200          *
 201          * Each flavor of ignoring needs different logic to skip whitespaces
 202          * while we have both sides to compare.
 203          */
 204         if (flags & XDF_IGNORE_WHITESPACE) {
 205                 goto skip_ws;
 206                 while (i1 < s1 && i2 < s2) {
 207                         if (l1[i1++] != l2[i2++])
 208                                 return 0;
 209                 skip_ws:
 210                         while (i1 < s1 && XDL_ISSPACE(l1[i1]))
 211                                 i1++;
 212                         while (i2 < s2 && XDL_ISSPACE(l2[i2]))
 213                                 i2++;
 214                 }
 215         } else if (flags & XDF_IGNORE_WHITESPACE_CHANGE) {
 216                 while (i1 < s1 && i2 < s2) {
 217                         if (XDL_ISSPACE(l1[i1]) && XDL_ISSPACE(l2[i2])) {
 218                                 /* Skip matching spaces and try again */
 219                                 while (i1 < s1 && XDL_ISSPACE(l1[i1]))
 220                                         i1++;
 221                                 while (i2 < s2 && XDL_ISSPACE(l2[i2]))
 222                                         i2++;
 223                                 continue;
 224                         }
 225                         if (l1[i1++] != l2[i2++])
 226                                 return 0;
 227                 }
 228         } else if (flags & XDF_IGNORE_WHITESPACE_AT_EOL) {
 229                 while (i1 < s1 && i2 < s2 && l1[i1++] == l2[i2++])
 230                         ; /* keep going */
 231         }
 232
 233         /*
 234          * After running out of one side, the remaining side must have
 235          * nothing but whitespace for the lines to match.  Note that
 236          * ignore-whitespace-at-eol case may break out of the loop
 237          * while there still are characters remaining on both lines.
 238          */
 239         if (i1 < s1) {
 240                 while (i1 < s1 && XDL_ISSPACE(l1[i1]))
 241                         i1++;
 242                 if (s1 != i1)
 243                         return 0;
 244         }
 245         if (i2 < s2) {
 246                 while (i2 < s2 && XDL_ISSPACE(l2[i2]))
 247                         i2++;
 248                 return (s2 == i2);
 249         }
 250         return 1;
 251 }
 252
 253 static unsigned long xdl_hash_record_with_whitespace(char const **data,
 254                 char const *top, long flags) {
 255         unsigned long ha = 5381;
 256         char const *ptr = *data;
 257
 258         for (; ptr < top && *ptr != '\n'; ptr++) {
 259                 if (XDL_ISSPACE(*ptr)) {
 260                         const char *ptr2 = ptr;
 261                         int at_eol;
 262                         while (ptr + 1 < top && XDL_ISSPACE(ptr[1])
 263                                         && ptr[1] != '\n')
 264                                 ptr++;
 265                         at_eol = (top <= ptr + 1 || ptr[1] == '\n');
 266                         if (flags & XDF_IGNORE_WHITESPACE)
 267                                 ; /* already handled */
 268                         else if (flags & XDF_IGNORE_WHITESPACE_CHANGE
 269                                  && !at_eol) {
 270                                 ha += (ha << 5);
 271                                 ha ^= (unsigned long) ' ';
 272                         }
 273                         else if (flags & XDF_IGNORE_WHITESPACE_AT_EOL
 274                                  && !at_eol) {
 275                                 while (ptr2 != ptr + 1) {
 276                                         ha += (ha << 5);
 277                                         ha ^= (unsigned long) *ptr2;
 278                                         ptr2++;
 279                                 }
 280                         }
 281                         continue;
 282                 }
 283                 ha += (ha << 5);
 284                 ha ^= (unsigned long) *ptr;
 285         }
 286         *data = ptr < top ? ptr + 1: ptr;
 287
 288         return ha;
 289 }
 290
 291
 292 unsigned long xdl_hash_record(char const **data, char const *top, long flags) {
 293         unsigned long ha = 5381;
 294         char const *ptr = *data;
 295
 296         if (flags & XDF_WHITESPACE_FLAGS)
 297                 return xdl_hash_record_with_whitespace(data, top, flags);
 298
 299         for (; ptr < top && *ptr != '\n'; ptr++) {
 300                 ha += (ha << 5);
 301                 ha ^= (unsigned long) *ptr;
 302         }
 303         *data = ptr < top ? ptr + 1: ptr;
 304
 305         return ha;
 306 }
 307
 308
 309 unsigned int xdl_hashbits(unsigned int size) {
 310         unsigned int val = 1, bits = 0;
 311
 312         for (; val < size && bits < CHAR_BIT * sizeof(unsigned int); val <<= 1, bits++);
 313         return bits ? bits: 1;
 314 }
 315
 316
 317 int xdl_num_out(char *out, long val) {
 318         char *ptr, *str = out;
 319         char buf[32];
 320
 321         ptr = buf + sizeof(buf) - 1;
 322         *ptr = '\0';
 323         if (val < 0) {
 324                 *--ptr = '-';
 325                 val = -val;
 326         }
 327         for (; val && ptr > buf; val /= 10)
 328                 *--ptr = "0123456789"[val % 10];
 329         if (*ptr)
 330                 for (; *ptr; ptr++, str++)
 331                         *str = *ptr;
 332         else
 333                 *str++ = '0';
 334         *str = '\0';
 335
 336         return str - out;
 337 }
 338
 339
 340 long xdl_atol(char const *str, char const **next) {
 341         long val, base;
 342         char const *top;
 343
 344         for (top = str; XDL_ISDIGIT(*top); top++);
 345         if (next)
 346                 *next = top;
 347         for (val = 0, base = 1, top--; top >= str; top--, base *= 10)
 348                 val += base * (long)(*top - '0');
 349         return val;
 350 }
 351
 352
 353 int xdl_emit_hunk_hdr(long s1, long c1, long s2, long c2,
 354                       const char *func, long funclen, xdemitcb_t *ecb) {
 355         int nb = 0;
 356         mmbuffer_t mb;
 357         char buf[128];
 358
 359         memcpy(buf, "@@ -", 4);
 360         nb += 4;
 361
 362         nb += xdl_num_out(buf + nb, c1 ? s1: s1 - 1);
 363
 364         if (c1 != 1) {
 365                 memcpy(buf + nb, ",", 1);
 366                 nb += 1;
 367
 368                 nb += xdl_num_out(buf + nb, c1);
 369         }
 370
 371         memcpy(buf + nb, " +", 2);
 372         nb += 2;
 373
 374         nb += xdl_num_out(buf + nb, c2 ? s2: s2 - 1);
 375
 376         if (c2 != 1) {
 377                 memcpy(buf + nb, ",", 1);
 378                 nb += 1;
 379
 380                 nb += xdl_num_out(buf + nb, c2);
 381         }
 382
 383         memcpy(buf + nb, " @@", 3);
 384         nb += 3;
 385         if (func && funclen) {
 386                 buf[nb++] = ' ';
 387                 if (funclen > sizeof(buf) - nb - 1)
 388                         funclen = sizeof(buf) - nb - 1;
 389                 memcpy(buf + nb, func, funclen);
 390                 nb += funclen;
 391         }
 392         buf[nb++] = '\n';
 393
 394         mb.ptr = buf;
 395         mb.size = nb;
 396         if (ecb->outf(ecb->priv, &mb, 1) < 0)
 397                 return -1;
 398
 399         return 0;
 400 }
 401
 402 int xdl_fall_back_diff(xdfenv_t *diff_env, xpparam_t const *xpp,
 403                 int line1, int count1, int line2, int count2)
 404 {
 405         /*
 406          * This probably does not work outside Git, since
 407          * we have a very simple mmfile structure.
 408          *
 409          * Note: ideally, we would reuse the prepared environment, but
 410          * the libxdiff interface does not (yet) allow for diffing only
 411          * ranges of lines instead of the whole files.
 412          */
 413         mmfile_t subfile1, subfile2;
 414         xdfenv_t env;
 415
 416         subfile1.ptr = (char *)diff_env->xdf1.recs[line1 - 1]->ptr;
 417         subfile1.size = diff_env->xdf1.recs[line1 + count1 - 2]->ptr +
 418                 diff_env->xdf1.recs[line1 + count1 - 2]->size - subfile1.ptr;
 419         subfile2.ptr = (char *)diff_env->xdf2.recs[line2 - 1]->ptr;
 420         subfile2.size = diff_env->xdf2.recs[line2 + count2 - 2]->ptr +
 421                 diff_env->xdf2.recs[line2 + count2 - 2]->size - subfile2.ptr;
 422         if (xdl_do_diff(&subfile1, &subfile2, xpp, &env) < 0)
 423                 return -1;
 424
 425         memcpy(diff_env->xdf1.rchg + line1 - 1, env.xdf1.rchg, count1);
 426         memcpy(diff_env->xdf2.rchg + line2 - 1, env.xdf2.rchg, count2);
 427
 428         xdl_free_env(&env);
 429
 430         return 0;
 431 }