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
  31
  32
  33
  34 static 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
  42 static 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  */
  60 xdchange_t *xdl_get_hunk(xdchange_t *xscr, xdemitconf_t const *xecfg) {
  61         xdchange_t *xch, *xchp;
  62
  63         for (xchp = xscr, xch = xscr->next; xch; xchp = xch, xch = xch->next)
  64                 if (xch->i1 - (xchp->i1 + xchp->chg1) > 2 * xecfg->ctxlen)
  65                         break;
  66
  67         return xchp;
  68 }
  69
  70
  71 static long def_ff(const char *rec, long len, char *buf, long sz, void *priv)
  72 {
  73         if (len > 0 &&
  74                         (isalpha((unsigned char)*rec) || /* identifier? */
  75                          *rec == '_' || /* also identifier? */
  76                          *rec == '$')) { /* identifiers from VMS and other esoterico */
  77                 if (len > sz)
  78                         len = sz;
  79                 while (0 < len && isspace((unsigned char)rec[len - 1]))
  80                         len--;
  81                 memcpy(buf, rec, len);
  82                 return len;
  83         }
  84         return -1;
  85 }
  86
  87 static void xdl_find_func(xdfile_t *xf, long i, char *buf, long sz, long *ll,
  88                 find_func_t ff, void *ff_priv) {
  89
  90         /*
  91          * Be quite stupid about this for now.  Find a line in the old file
  92          * before the start of the hunk (and context) which starts with a
  93          * plausible character.
  94          */
  95
  96         const char *rec;
  97         long len;
  98
  99         while (i-- > 0) {
 100                 len = xdl_get_rec(xf, i, &rec);
 101                 if ((*ll = ff(rec, len, buf, sz, ff_priv)) >= 0)
 102                         return;
 103         }
 104         *ll = 0;
 105 }
 106
 107
 108 static int xdl_emit_common(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
 109                            xdemitconf_t const *xecfg) {
 110         xdfile_t *xdf = &xe->xdf1;
 111         const char *rchg = xdf->rchg;
 112         long ix;
 113
 114         for (ix = 0; ix < xdf->nrec; ix++) {
 115                 if (rchg[ix])
 116                         continue;
 117                 if (xdl_emit_record(xdf, ix, "", ecb))
 118                         return -1;
 119         }
 120         return 0;
 121 }
 122
 123 int xdl_emit_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
 124                   xdemitconf_t const *xecfg) {
 125         long s1, s2, e1, e2, lctx;
 126         xdchange_t *xch, *xche;
 127         char funcbuf[80];
 128         long funclen = 0;
 129         find_func_t ff = xecfg->find_func ?  xecfg->find_func : def_ff;
 130
 131         if (xecfg->flags & XDL_EMIT_COMMON)
 132                 return xdl_emit_common(xe, xscr, ecb, xecfg);
 133
 134         for (xch = xche = xscr; xch; xch = xche->next) {
 135                 xche = xdl_get_hunk(xch, xecfg);
 136
 137                 s1 = XDL_MAX(xch->i1 - xecfg->ctxlen, 0);
 138                 s2 = XDL_MAX(xch->i2 - xecfg->ctxlen, 0);
 139
 140                 lctx = xecfg->ctxlen;
 141                 lctx = XDL_MIN(lctx, xe->xdf1.nrec - (xche->i1 + xche->chg1));
 142                 lctx = XDL_MIN(lctx, xe->xdf2.nrec - (xche->i2 + xche->chg2));
 143
 144                 e1 = xche->i1 + xche->chg1 + lctx;
 145                 e2 = xche->i2 + xche->chg2 + lctx;
 146
 147                 /*
 148                  * Emit current hunk header.
 149                  */
 150
 151                 if (xecfg->flags & XDL_EMIT_FUNCNAMES) {
 152                         xdl_find_func(&xe->xdf1, s1, funcbuf,
 153                                       sizeof(funcbuf), &funclen,
 154                                       ff, xecfg->find_func_priv);
 155                 }
 156                 if (xdl_emit_hunk_hdr(s1 + 1, e1 - s1, s2 + 1, e2 - s2,
 157                                       funcbuf, funclen, ecb) < 0)
 158                         return -1;
 159
 160                 /*
 161                  * Emit pre-context.
 162                  */
 163                 for (; s1 < xch->i1; s1++)
 164                         if (xdl_emit_record(&xe->xdf1, s1, " ", ecb) < 0)
 165                                 return -1;
 166
 167                 for (s1 = xch->i1, s2 = xch->i2;; xch = xch->next) {
 168                         /*
 169                          * Merge previous with current change atom.
 170                          */
 171                         for (; s1 < xch->i1 && s2 < xch->i2; s1++, s2++)
 172                                 if (xdl_emit_record(&xe->xdf1, s1, " ", ecb) < 0)
 173                                         return -1;
 174
 175                         /*
 176                          * Removes lines from the first file.
 177                          */
 178                         for (s1 = xch->i1; s1 < xch->i1 + xch->chg1; s1++)
 179                                 if (xdl_emit_record(&xe->xdf1, s1, "-", ecb) < 0)
 180                                         return -1;
 181
 182                         /*
 183                          * Adds lines from the second file.
 184                          */
 185                         for (s2 = xch->i2; s2 < xch->i2 + xch->chg2; s2++)
 186                                 if (xdl_emit_record(&xe->xdf2, s2, "+", ecb) < 0)
 187                                         return -1;
 188
 189                         if (xch == xche)
 190                                 break;
 191                         s1 = xch->i1 + xch->chg1;
 192                         s2 = xch->i2 + xch->chg2;
 193                 }
 194
 195                 /*
 196                  * Emit post-context.
 197                  */
 198                 for (s1 = xche->i1 + xche->chg1; s1 < e1; s1++)
 199                         if (xdl_emit_record(&xe->xdf1, s1, " ", ecb) < 0)
 200                                 return -1;
 201         }
 202
 203         return 0;
 204 }