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 int xdl_emit_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
  73                   xdemitconf_t const *xecfg) {
  74         long s1, s2, e1, e2, lctx;
  75         xdchange_t *xch, *xche;
  76
  77         for (xch = xche = xscr; xch; xch = xche->next) {
  78                 xche = xdl_get_hunk(xch, xecfg);
  79
  80                 s1 = XDL_MAX(xch->i1 - xecfg->ctxlen, 0);
  81                 s2 = XDL_MAX(xch->i2 - xecfg->ctxlen, 0);
  82
  83                 lctx = xecfg->ctxlen;
  84                 lctx = XDL_MIN(lctx, xe->xdf1.nrec - (xche->i1 + xche->chg1));
  85                 lctx = XDL_MIN(lctx, xe->xdf2.nrec - (xche->i2 + xche->chg2));
  86
  87                 e1 = xche->i1 + xche->chg1 + lctx;
  88                 e2 = xche->i2 + xche->chg2 + lctx;
  89
  90                 /*
  91                  * Emit current hunk header.
  92                  */
  93                 if (xdl_emit_hunk_hdr(s1 + 1, e1 - s1, s2 + 1, e2 - s2, ecb) < 0)
  94                         return -1;
  95
  96                 /*
  97                  * Emit pre-context.
  98                  */
  99                 for (; s1 < xch->i1; s1++)
 100                         if (xdl_emit_record(&xe->xdf1, s1, " ", ecb) < 0)
 101                                 return -1;
 102
 103                 for (s1 = xch->i1, s2 = xch->i2;; xch = xch->next) {
 104                         /*
 105                          * Merge previous with current change atom.
 106                          */
 107                         for (; s1 < xch->i1 && s2 < xch->i2; s1++, s2++)
 108                                 if (xdl_emit_record(&xe->xdf1, s1, " ", ecb) < 0)
 109                                         return -1;
 110
 111                         /*
 112                          * Removes lines from the first file.
 113                          */
 114                         for (s1 = xch->i1; s1 < xch->i1 + xch->chg1; s1++)
 115                                 if (xdl_emit_record(&xe->xdf1, s1, "-", ecb) < 0)
 116                                         return -1;
 117
 118                         /*
 119                          * Adds lines from the second file.
 120                          */
 121                         for (s2 = xch->i2; s2 < xch->i2 + xch->chg2; s2++)
 122                                 if (xdl_emit_record(&xe->xdf2, s2, "+", ecb) < 0)
 123                                         return -1;
 124
 125                         if (xch == xche)
 126                                 break;
 127                         s1 = xch->i1 + xch->chg1;
 128                         s2 = xch->i2 + xch->chg2;
 129                 }
 130
 131                 /*
 132                  * Emit post-context.
 133                  */
 134                 for (s1 = xche->i1 + xche->chg1; s1 < e1; s1++)
 135                         if (xdl_emit_record(&xe->xdf1, s1, " ", ecb) < 0)
 136                                 return -1;
 137         }
 138
 139         return 0;
 140 }
 141