xdiff/xemit.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 static long xdl_get_rec(xdfile_t *xdf, long ri, char const **rec);
  29 static int xdl_emit_record(xdfile_t *xdf, long ri, char const *pre, xdemitcb_t *ecb);
  30 static xdchange_t *xdl_get_hunk(xdchange_t *xscr, xdemitconf_t const *xecfg);
  31
  32
  33
  34
  35 static long xdl_get_rec(xdfile_t *xdf, long ri, char const **rec) {
  36
  37         *rec = xdf->recs[ri]->ptr;
  38
  39         return xdf->recs[ri]->size;
  40 }
  41
  42
  43 static int xdl_emit_record(xdfile_t *xdf, long ri, char const *pre, xdemitcb_t *ecb) {
  44         long size, psize = strlen(pre);
  45         char const *rec;
  46
  47         size = xdl_get_rec(xdf, ri, &rec);
  48         if (xdl_emit_diffrec(rec, size, pre, psize, ecb) < 0) {
  49
  50                 return -1;
  51         }
  52
  53         return 0;
  54 }
  55
  56
  57 /*
  58  * Starting at the passed change atom, find the latest change atom to be included
  59  * inside the differential hunk according to the specified configuration.
  60  */
  61 static xdchange_t *xdl_get_hunk(xdchange_t *xscr, xdemitconf_t const *xecfg) {
  62         xdchange_t *xch, *xchp;
  63
  64         for (xchp = xscr, xch = xscr->next; xch; xchp = xch, xch = xch->next)
  65                 if (xch->i1 - (xchp->i1 + xchp->chg1) > 2 * xecfg->ctxlen)
  66                         break;
  67
  68         return xchp;
  69 }
  70
  71
  72 static void xdl_find_func(xdfile_t *xf, long i, char *buf, long sz, long *ll) {
  73
  74         /*
  75          * Be quite stupid about this for now.  Find a line in the old file
  76          * before the start of the hunk (and context) which starts with a
  77          * plausible character.
  78          */
  79
  80         const char *rec;
  81         long len;
  82
  83         *ll = 0;
  84         while (i-- > 0) {
  85                 len = xdl_get_rec(xf, i, &rec);
  86                 if (len > 0 &&
  87                     (isalpha((unsigned char)*rec) || /* identifier? */
  88                      *rec == '_' ||     /* also identifier? */
  89                      *rec == '$')) {    /* mysterious GNU diff's invention */
  90                         if (len > sz)
  91                                 len = sz;
  92                         while (0 < len && isspace((unsigned char)rec[len - 1]))
  93                                 len--;
  94                         memcpy(buf, rec, len);
  95                         *ll = len;
  96                         return;
  97                 }
  98         }
  99 }
 100
 101
 102 int xdl_emit_common(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
 103                     xdemitconf_t const *xecfg) {
 104         xdfile_t *xdf = &xe->xdf1;
 105         const char *rchg = xdf->rchg;
 106         long ix;
 107
 108         for (ix = 0; ix < xdf->nrec; ix++) {
 109                 if (rchg[ix])
 110                         continue;
 111                 if (xdl_emit_record(xdf, ix, "", ecb))
 112                         return -1;
 113         }
 114         return 0;
 115 }
 116
 117 int xdl_emit_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
 118                   xdemitconf_t const *xecfg) {
 119         long s1, s2, e1, e2, lctx;
 120         xdchange_t *xch, *xche;
 121         char funcbuf[40];
 122         long funclen = 0;
 123
 124         if (xecfg->flags & XDL_EMIT_COMMON)
 125                 return xdl_emit_common(xe, xscr, ecb, xecfg);
 126
 127         for (xch = xche = xscr; xch; xch = xche->next) {
 128                 xche = xdl_get_hunk(xch, xecfg);
 129
 130                 s1 = XDL_MAX(xch->i1 - xecfg->ctxlen, 0);
 131                 s2 = XDL_MAX(xch->i2 - xecfg->ctxlen, 0);
 132
 133                 lctx = xecfg->ctxlen;
 134                 lctx = XDL_MIN(lctx, xe->xdf1.nrec - (xche->i1 + xche->chg1));
 135                 lctx = XDL_MIN(lctx, xe->xdf2.nrec - (xche->i2 + xche->chg2));
 136
 137                 e1 = xche->i1 + xche->chg1 + lctx;
 138                 e2 = xche->i2 + xche->chg2 + lctx;
 139
 140                 /*
 141                  * Emit current hunk header.
 142                  */
 143
 144                 if (xecfg->flags & XDL_EMIT_FUNCNAMES) {
 145                         xdl_find_func(&xe->xdf1, s1, funcbuf,
 146                                       sizeof(funcbuf), &funclen);
 147                 }
 148                 if (xdl_emit_hunk_hdr(s1 + 1, e1 - s1, s2 + 1, e2 - s2,
 149                                       funcbuf, funclen, ecb) < 0)
 150                         return -1;
 151
 152                 /*
 153                  * Emit pre-context.
 154                  */
 155                 for (; s1 < xch->i1; s1++)
 156                         if (xdl_emit_record(&xe->xdf1, s1, " ", ecb) < 0)
 157                                 return -1;
 158
 159                 for (s1 = xch->i1, s2 = xch->i2;; xch = xch->next) {
 160                         /*
 161                          * Merge previous with current change atom.
 162                          */
 163                         for (; s1 < xch->i1 && s2 < xch->i2; s1++, s2++)
 164                                 if (xdl_emit_record(&xe->xdf1, s1, " ", ecb) < 0)
 165                                         return -1;
 166
 167                         /*
 168                          * Removes lines from the first file.
 169                          */
 170                         for (s1 = xch->i1; s1 < xch->i1 + xch->chg1; s1++)
 171                                 if (xdl_emit_record(&xe->xdf1, s1, "-", ecb) < 0)
 172                                         return -1;
 173
 174                         /*
 175                          * Adds lines from the second file.
 176                          */
 177                         for (s2 = xch->i2; s2 < xch->i2 + xch->chg2; s2++)
 178                                 if (xdl_emit_record(&xe->xdf2, s2, "+", ecb) < 0)
 179                                         return -1;
 180
 181                         if (xch == xche)
 182                                 break;
 183                         s1 = xch->i1 + xch->chg1;
 184                         s2 = xch->i2 + xch->chg2;
 185                 }
 186
 187                 /*
 188                  * Emit post-context.
 189                  */
 190                 for (s1 = xche->i1 + xche->chg1; s1 < e1; s1++)
 191                         if (xdl_emit_record(&xe->xdf1, s1, " ", ecb) < 0)
 192                                 return -1;
 193         }
 194
 195         return 0;
 196 }
 197