Andrew's git - gitweb.git/blob

969100d99d4bfd7c86cf4464ebecc0564db1c1b7
   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
  28static long xdl_get_rec(xdfile_t *xdf, long ri, char const **rec);
  29static int xdl_emit_record(xdfile_t *xdf, long ri, char const *pre, xdemitcb_t *ecb);
  30
  31
  32
  33
  34static long xdl_get_rec(xdfile_t *xdf, long ri, char const **rec) {
  35
  36        *rec = xdf->recs[ri]->ptr;
  37
  38        return xdf->recs[ri]->size;
  39}
  40
  41
  42static int xdl_emit_record(xdfile_t *xdf, long ri, char const *pre, xdemitcb_t *ecb) {
  43        long size, psize = strlen(pre);
  44        char const *rec;
  45
  46        size = xdl_get_rec(xdf, ri, &rec);
  47        if (xdl_emit_diffrec(rec, size, pre, psize, ecb) < 0) {
  48
  49                return -1;
  50        }
  51
  52        return 0;
  53}
  54
  55
  56/*
  57 * Starting at the passed change atom, find the latest change atom to be included
  58 * inside the differential hunk according to the specified configuration.
  59 * Also advance xscr if the first changes must be discarded.
  60 */
  61xdchange_t *xdl_get_hunk(xdchange_t **xscr, xdemitconf_t const *xecfg)
  62{
  63        xdchange_t *xch, *xchp, *lxch;
  64        long max_common = 2 * xecfg->ctxlen + xecfg->interhunkctxlen;
  65        long max_ignorable = xecfg->ctxlen;
  66        unsigned long ignored = 0; /* number of ignored blank lines */
  67
  68        /* remove ignorable changes that are too far before other changes */
  69        for (xchp = *xscr; xchp && xchp->ignore; xchp = xchp->next) {
  70                xch = xchp->next;
  71
  72                if (xch == NULL ||
  73                    xch->i1 - (xchp->i1 + xchp->chg1) >= max_ignorable)
  74                        *xscr = xch;
  75        }
  76
  77        if (*xscr == NULL)
  78                return NULL;
  79
  80        lxch = *xscr;
  81
  82        for (xchp = *xscr, xch = xchp->next; xch; xchp = xch, xch = xch->next) {
  83                long distance = xch->i1 - (xchp->i1 + xchp->chg1);
  84                if (distance > max_common)
  85                        break;
  86
  87                if (distance < max_ignorable && (!xch->ignore || lxch == xchp)) {
  88                        lxch = xch;
  89                        ignored = 0;
  90                } else if (distance < max_ignorable && xch->ignore) {
  91                        ignored += xch->chg2;
  92                } else if (lxch != xchp &&
  93                           xch->i1 + ignored - (lxch->i1 + lxch->chg1) > max_common) {
  94                        break;
  95                } else if (!xch->ignore) {
  96                        lxch = xch;
  97                        ignored = 0;
  98                } else {
  99                        ignored += xch->chg2;
 100                }
 101        }
 102
 103        return lxch;
 104}
 105
 106
 107static long def_ff(const char *rec, long len, char *buf, long sz, void *priv)
 108{
 109        if (len > 0 &&
 110                        (isalpha((unsigned char)*rec) || /* identifier? */
 111                         *rec == '_' || /* also identifier? */
 112                         *rec == '$')) { /* identifiers from VMS and other esoterico */
 113                if (len > sz)
 114                        len = sz;
 115                while (0 < len && isspace((unsigned char)rec[len - 1]))
 116                        len--;
 117                memcpy(buf, rec, len);
 118                return len;
 119        }
 120        return -1;
 121}
 122
 123static long match_func_rec(xdfile_t *xdf, xdemitconf_t const *xecfg, long ri,
 124                           char *buf, long sz)
 125{
 126        const char *rec;
 127        long len = xdl_get_rec(xdf, ri, &rec);
 128        if (!xecfg->find_func)
 129                return def_ff(rec, len, buf, sz, xecfg->find_func_priv);
 130        return xecfg->find_func(rec, len, buf, sz, xecfg->find_func_priv);
 131}
 132
 133struct func_line {
 134        long len;
 135        char buf[80];
 136};
 137
 138static long get_func_line(xdfenv_t *xe, xdemitconf_t const *xecfg,
 139                          struct func_line *func_line, long start, long limit)
 140{
 141        long l, size, step = (start > limit) ? -1 : 1;
 142        char *buf, dummy[1];
 143
 144        buf = func_line ? func_line->buf : dummy;
 145        size = func_line ? sizeof(func_line->buf) : sizeof(dummy);
 146
 147        for (l = start; l != limit && 0 <= l && l < xe->xdf1.nrec; l += step) {
 148                long len = match_func_rec(&xe->xdf1, xecfg, l, buf, size);
 149                if (len >= 0) {
 150                        if (func_line)
 151                                func_line->len = len;
 152                        return l;
 153                }
 154        }
 155        return -1;
 156}
 157
 158int xdl_emit_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
 159                  xdemitconf_t const *xecfg) {
 160        long s1, s2, e1, e2, lctx;
 161        xdchange_t *xch, *xche;
 162        long funclineprev = -1;
 163        struct func_line func_line = { 0 };
 164
 165        for (xch = xscr; xch; xch = xche->next) {
 166                xche = xdl_get_hunk(&xch, xecfg);
 167                if (!xch)
 168                        break;
 169
 170                s1 = XDL_MAX(xch->i1 - xecfg->ctxlen, 0);
 171                s2 = XDL_MAX(xch->i2 - xecfg->ctxlen, 0);
 172
 173                if (xecfg->flags & XDL_EMIT_FUNCCONTEXT) {
 174                        long fs1, i1 = xch->i1;
 175
 176                        /* Appended chunk? */
 177                        if (i1 >= xe->xdf1.nrec) {
 178                                char dummy[1];
 179
 180                                /*
 181                                 * We don't need additional context if
 182                                 * a whole function was added.
 183                                 */
 184                                if (match_func_rec(&xe->xdf2, xecfg, xch->i2,
 185                                                   dummy, sizeof(dummy)) >= 0)
 186                                        goto post_context_calculation;
 187
 188                                /*
 189                                 * Otherwise get more context from the
 190                                 * pre-image.
 191                                 */
 192                                i1 = xe->xdf1.nrec - 1;
 193                        }
 194
 195                        fs1 = get_func_line(xe, xecfg, NULL, i1, -1);
 196                        if (fs1 < 0)
 197                                fs1 = 0;
 198                        if (fs1 < s1) {
 199                                s2 -= s1 - fs1;
 200                                s1 = fs1;
 201                        }
 202                }
 203
 204 post_context_calculation:
 205                lctx = xecfg->ctxlen;
 206                lctx = XDL_MIN(lctx, xe->xdf1.nrec - (xche->i1 + xche->chg1));
 207                lctx = XDL_MIN(lctx, xe->xdf2.nrec - (xche->i2 + xche->chg2));
 208
 209                e1 = xche->i1 + xche->chg1 + lctx;
 210                e2 = xche->i2 + xche->chg2 + lctx;
 211
 212                if (xecfg->flags & XDL_EMIT_FUNCCONTEXT) {
 213                        long fe1 = get_func_line(xe, xecfg, NULL,
 214                                                 xche->i1 + xche->chg1,
 215                                                 xe->xdf1.nrec);
 216                        if (fe1 < 0)
 217                                fe1 = xe->xdf1.nrec;
 218                        if (fe1 > e1) {
 219                                e2 += fe1 - e1;
 220                                e1 = fe1;
 221                        }
 222
 223                        /*
 224                         * Overlap with next change?  Then include it
 225                         * in the current hunk and start over to find
 226                         * its new end.
 227                         */
 228                        if (xche->next) {
 229                                long l = xche->next->i1;
 230                                if (l <= e1 ||
 231                                    get_func_line(xe, xecfg, NULL, l, e1) < 0) {
 232                                        xche = xche->next;
 233                                        goto post_context_calculation;
 234                                }
 235                        }
 236                }
 237
 238                /*
 239                 * Emit current hunk header.
 240                 */
 241
 242                if (xecfg->flags & XDL_EMIT_FUNCNAMES) {
 243                        get_func_line(xe, xecfg, &func_line,
 244                                      s1 - 1, funclineprev);
 245                        funclineprev = s1 - 1;
 246                }
 247                if (xdl_emit_hunk_hdr(s1 + 1, e1 - s1, s2 + 1, e2 - s2,
 248                                      func_line.buf, func_line.len, ecb) < 0)
 249                        return -1;
 250
 251                /*
 252                 * Emit pre-context.
 253                 */
 254                for (; s2 < xch->i2; s2++)
 255                        if (xdl_emit_record(&xe->xdf2, s2, " ", ecb) < 0)
 256                                return -1;
 257
 258                for (s1 = xch->i1, s2 = xch->i2;; xch = xch->next) {
 259                        /*
 260                         * Merge previous with current change atom.
 261                         */
 262                        for (; s1 < xch->i1 && s2 < xch->i2; s1++, s2++)
 263                                if (xdl_emit_record(&xe->xdf2, s2, " ", ecb) < 0)
 264                                        return -1;
 265
 266                        /*
 267                         * Removes lines from the first file.
 268                         */
 269                        for (s1 = xch->i1; s1 < xch->i1 + xch->chg1; s1++)
 270                                if (xdl_emit_record(&xe->xdf1, s1, "-", ecb) < 0)
 271                                        return -1;
 272
 273                        /*
 274                         * Adds lines from the second file.
 275                         */
 276                        for (s2 = xch->i2; s2 < xch->i2 + xch->chg2; s2++)
 277                                if (xdl_emit_record(&xe->xdf2, s2, "+", ecb) < 0)
 278                                        return -1;
 279
 280                        if (xch == xche)
 281                                break;
 282                        s1 = xch->i1 + xch->chg1;
 283                        s2 = xch->i2 + xch->chg2;
 284                }
 285
 286                /*
 287                 * Emit post-context.
 288                 */
 289                for (s2 = xche->i2 + xche->chg2; s2 < e2; s2++)
 290                        if (xdl_emit_record(&xe->xdf2, s2, " ", ecb) < 0)
 291                                return -1;
 292        }
 293
 294        return 0;
 295}