Use a *real* built-in diff generator

[git.git] / xdiff / xemit.c

diff --git a/xdiff/xemit.c b/xdiff/xemit.c
new file mode 100644 (file)
index 0000000..2e5d54c
--- /dev/null
+++ b/xdiff/xemit.c
@@ -0,0 +1,141 @@
+/*
+ *  LibXDiff by Davide Libenzi ( File Differential Library )
+ *  Copyright (C) 2003 Davide Libenzi
+ *
+ *  This library is free software; you can redistribute it and/or
+ *  modify it under the terms of the GNU Lesser General Public
+ *  License as published by the Free Software Foundation; either
+ *  version 2.1 of the License, or (at your option) any later version.
+ *
+ *  This library is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ *  Lesser General Public License for more details.
+ *
+ *  You should have received a copy of the GNU Lesser General Public
+ *  License along with this library; if not, write to the Free Software
+ *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
+ *
+ *  Davide Libenzi <davidel@xmailserver.org>
+ *
+ */
+
+#include "xinclude.h"
+
+
+
+
+static long xdl_get_rec(xdfile_t *xdf, long ri, char const **rec);
+static int xdl_emit_record(xdfile_t *xdf, long ri, char const *pre, xdemitcb_t *ecb);
+static xdchange_t *xdl_get_hunk(xdchange_t *xscr, xdemitconf_t const *xecfg);
+
+
+
+
+static long xdl_get_rec(xdfile_t *xdf, long ri, char const **rec) {
+
+       *rec = xdf->recs[ri]->ptr;
+
+       return xdf->recs[ri]->size;
+}
+
+
+static int xdl_emit_record(xdfile_t *xdf, long ri, char const *pre, xdemitcb_t *ecb) {
+       long size, psize = strlen(pre);
+       char const *rec;
+
+       size = xdl_get_rec(xdf, ri, &rec);
+       if (xdl_emit_diffrec(rec, size, pre, psize, ecb) < 0) {
+
+               return -1;
+       }
+
+       return 0;
+}
+
+
+/*
+ * Starting at the passed change atom, find the latest change atom to be included
+ * inside the differential hunk according to the specified configuration.
+ */
+static xdchange_t *xdl_get_hunk(xdchange_t *xscr, xdemitconf_t const *xecfg) {
+       xdchange_t *xch, *xchp;
+
+       for (xchp = xscr, xch = xscr->next; xch; xchp = xch, xch = xch->next)
+               if (xch->i1 - (xchp->i1 + xchp->chg1) > 2 * xecfg->ctxlen)
+                       break;
+
+       return xchp;
+}
+
+
+int xdl_emit_diff(xdfenv_t *xe, xdchange_t *xscr, xdemitcb_t *ecb,
+                 xdemitconf_t const *xecfg) {
+       long s1, s2, e1, e2, lctx;
+       xdchange_t *xch, *xche;
+
+       for (xch = xche = xscr; xch; xch = xche->next) {
+               xche = xdl_get_hunk(xch, xecfg);
+
+               s1 = XDL_MAX(xch->i1 - xecfg->ctxlen, 0);
+               s2 = XDL_MAX(xch->i2 - xecfg->ctxlen, 0);
+
+               lctx = xecfg->ctxlen;
+               lctx = XDL_MIN(lctx, xe->xdf1.nrec - (xche->i1 + xche->chg1));
+               lctx = XDL_MIN(lctx, xe->xdf2.nrec - (xche->i2 + xche->chg2));
+
+               e1 = xche->i1 + xche->chg1 + lctx;
+               e2 = xche->i2 + xche->chg2 + lctx;
+
+               /*
+                * Emit current hunk header.
+                */
+               if (xdl_emit_hunk_hdr(s1 + 1, e1 - s1, s2 + 1, e2 - s2, ecb) < 0)
+                       return -1;
+
+               /*
+                * Emit pre-context.
+                */
+               for (; s1 < xch->i1; s1++)
+                       if (xdl_emit_record(&xe->xdf1, s1, " ", ecb) < 0)
+                               return -1;
+
+               for (s1 = xch->i1, s2 = xch->i2;; xch = xch->next) {
+                       /*
+                        * Merge previous with current change atom.
+                        */
+                       for (; s1 < xch->i1 && s2 < xch->i2; s1++, s2++)
+                               if (xdl_emit_record(&xe->xdf1, s1, " ", ecb) < 0)
+                                       return -1;
+
+                       /*
+                        * Removes lines from the first file.
+                        */
+                       for (s1 = xch->i1; s1 < xch->i1 + xch->chg1; s1++)
+                               if (xdl_emit_record(&xe->xdf1, s1, "-", ecb) < 0)
+                                       return -1;
+
+                       /*
+                        * Adds lines from the second file.
+                        */
+                       for (s2 = xch->i2; s2 < xch->i2 + xch->chg2; s2++)
+                               if (xdl_emit_record(&xe->xdf2, s2, "+", ecb) < 0)
+                                       return -1;
+
+                       if (xch == xche)
+                               break;
+                       s1 = xch->i1 + xch->chg1;
+                       s2 = xch->i2 + xch->chg2;
+               }
+
+               /*
+                * Emit post-context.
+                */
+               for (s1 = xche->i1 + xche->chg1; s1 < e1; s1++)
+                       if (xdl_emit_record(&xe->xdf1, s1, " ", ecb) < 0)
+                               return -1;
+       }
+
+       return 0;
+}
+