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