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         long max_common = 2 * xecfg->ctxlen + xecfg->interhunkctxlen;
  63
  64         for (xchp = xscr, xch = xscr->next; xch; xchp = xch, xch = xch->next)
  65                 if (xch->i1 - (xchp->i1 + xchp->chg1) > max_common)
  66                         break;
  67
  68         return xchp;
  69 }
  70
  71
  72 static long def_ff(const char *rec, long len, char *buf, long sz, void *priv)
  73 {
  74         if (len > 0 &&
  75                         (isalpha((unsigned char)*rec) || /* identifier? */
  76                          *rec == '_' || /* also identifier? */
  77                          *rec == '$')) { /* identifiers from VMS and other esoterico */
  78                 if (len > sz)
  79                         len = sz;
  80                 while (0 < len && isspace((unsigned char)rec[len - 1]))
  81                         len--;
  82                 memcpy(buf, rec, len);
  83                 return len;
  84         }
  85         return -1;
  86 }
  87
  88 static int xdl_emit_common(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
  89                            xdemitconf_t const *xecfg) {
  90         xdfile_t *xdf = &xe->xdf1;
  91         const char *rchg = xdf->rchg;
  92         long ix;
  93
  94         for (ix = 0; ix < xdf->nrec; ix++) {
  95                 if (rchg[ix])
  96                         continue;
  97                 if (xdl_emit_record(xdf, ix, "", ecb))
  98                         return -1;
  99         }
 100         return 0;
 101 }
 102
 103 struct func_line {
 104         long len;
 105         char buf[80];
 106 };
 107
 108 static long get_func_line(xdfenv_t *xe, xdemitconf_t const *xecfg,
 109                           struct func_line *func_line, long start, long limit)
 110 {
 111         find_func_t ff = xecfg->find_func ? xecfg->find_func : def_ff;
 112         long l, size, step = (start > limit) ? -1 : 1;
 113         char *buf, dummy[1];
 114
 115         buf = func_line ? func_line->buf : dummy;
 116         size = func_line ? sizeof(func_line->buf) : sizeof(dummy);
 117
 118         for (l = start; l != limit && 0 <= l && l < xe->xdf1.nrec; l += step) {
 119                 const char *rec;
 120                 long reclen = xdl_get_rec(&xe->xdf1, l, &rec);
 121                 long len = ff(rec, reclen, buf, size, xecfg->find_func_priv);
 122                 if (len >= 0) {
 123                         if (func_line)
 124                                 func_line->len = len;
 125                         return l;
 126                 }
 127         }
 128         return -1;
 129 }
 130
 131 int xdl_emit_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
 132                   xdemitconf_t const *xecfg) {
 133         long s1, s2, e1, e2, lctx;
 134         xdchange_t *xch, *xche;
 135         long funclineprev = -1;
 136         struct func_line func_line = { 0 };
 137
 138         if (xecfg->flags & XDL_EMIT_COMMON)
 139                 return xdl_emit_common(xe, xscr, ecb, xecfg);
 140
 141         for (xch = xscr; xch; xch = xche->next) {
 142                 xche = xdl_get_hunk(xch, xecfg);
 143
 144                 s1 = XDL_MAX(xch->i1 - xecfg->ctxlen, 0);
 145                 s2 = XDL_MAX(xch->i2 - xecfg->ctxlen, 0);
 146
 147                 if (xecfg->flags & XDL_EMIT_FUNCCONTEXT) {
 148                         long fs1 = get_func_line(xe, xecfg, NULL, xch->i1, -1);
 149                         if (fs1 < 0)
 150                                 fs1 = 0;
 151                         if (fs1 < s1) {
 152                                 s2 -= s1 - fs1;
 153                                 s1 = fs1;
 154                         }
 155                 }
 156
 157  again:
 158                 lctx = xecfg->ctxlen;
 159                 lctx = XDL_MIN(lctx, xe->xdf1.nrec - (xche->i1 + xche->chg1));
 160                 lctx = XDL_MIN(lctx, xe->xdf2.nrec - (xche->i2 + xche->chg2));
 161
 162                 e1 = xche->i1 + xche->chg1 + lctx;
 163                 e2 = xche->i2 + xche->chg2 + lctx;
 164
 165                 if (xecfg->flags & XDL_EMIT_FUNCCONTEXT) {
 166                         long fe1 = get_func_line(xe, xecfg, NULL,
 167                                                  xche->i1 + xche->chg1,
 168                                                  xe->xdf1.nrec);
 169                         if (fe1 < 0)
 170                                 fe1 = xe->xdf1.nrec;
 171                         if (fe1 > e1) {
 172                                 e2 += fe1 - e1;
 173                                 e1 = fe1;
 174                         }
 175
 176                         /*
 177                          * Overlap with next change?  Then include it
 178                          * in the current hunk and start over to find
 179                          * its new end.
 180                          */
 181                         if (xche->next) {
 182                                 long l = xche->next->i1;
 183                                 if (l <= e1 ||
 184                                     get_func_line(xe, xecfg, NULL, l, e1) < 0) {
 185                                         xche = xche->next;
 186                                         goto again;
 187                                 }
 188                         }
 189                 }
 190
 191                 /*
 192                  * Emit current hunk header.
 193                  */
 194
 195                 if (xecfg->flags & XDL_EMIT_FUNCNAMES) {
 196                         get_func_line(xe, xecfg, &func_line,
 197                                       s1 - 1, funclineprev);
 198                         funclineprev = s1 - 1;
 199                 }
 200                 if (xdl_emit_hunk_hdr(s1 + 1, e1 - s1, s2 + 1, e2 - s2,
 201                                       func_line.buf, func_line.len, ecb) < 0)
 202                         return -1;
 203
 204                 /*
 205                  * Emit pre-context.
 206                  */
 207                 for (; s1 < xch->i1; s1++)
 208                         if (xdl_emit_record(&xe->xdf1, s1, " ", ecb) < 0)
 209                                 return -1;
 210
 211                 for (s1 = xch->i1, s2 = xch->i2;; xch = xch->next) {
 212                         /*
 213                          * Merge previous with current change atom.
 214                          */
 215                         for (; s1 < xch->i1 && s2 < xch->i2; s1++, s2++)
 216                                 if (xdl_emit_record(&xe->xdf1, s1, " ", ecb) < 0)
 217                                         return -1;
 218
 219                         /*
 220                          * Removes lines from the first file.
 221                          */
 222                         for (s1 = xch->i1; s1 < xch->i1 + xch->chg1; s1++)
 223                                 if (xdl_emit_record(&xe->xdf1, s1, "-", ecb) < 0)
 224                                         return -1;
 225
 226                         /*
 227                          * Adds lines from the second file.
 228                          */
 229                         for (s2 = xch->i2; s2 < xch->i2 + xch->chg2; s2++)
 230                                 if (xdl_emit_record(&xe->xdf2, s2, "+", ecb) < 0)
 231                                         return -1;
 232
 233                         if (xch == xche)
 234                                 break;
 235                         s1 = xch->i1 + xch->chg1;
 236                         s2 = xch->i2 + xch->chg2;
 237                 }
 238
 239                 /*
 240                  * Emit post-context.
 241                  */
 242                 for (s1 = xche->i1 + xche->chg1; s1 < e1; s1++)
 243                         if (xdl_emit_record(&xe->xdf1, s1, " ", ecb) < 0)
 244                                 return -1;
 245         }
 246
 247         return 0;
 248 }