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-rw-r--r--xdiff/xemit.c329
1 files changed, 329 insertions, 0 deletions
diff --git a/xdiff/xemit.c b/xdiff/xemit.c
new file mode 100644
index 0000000..9d7d6c5
--- /dev/null
+++ b/xdiff/xemit.c
@@ -0,0 +1,329 @@
+/*
+ * 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, see
+ * <http://www.gnu.org/licenses/>.
+ *
+ * Davide Libenzi <davidel@xmailserver.org>
+ *
+ */
+
+#include "xinclude.h"
+
+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.
+ * Also advance xscr if the first changes must be discarded.
+ */
+xdchange_t *xdl_get_hunk(xdchange_t **xscr, xdemitconf_t const *xecfg)
+{
+ xdchange_t *xch, *xchp, *lxch;
+ long max_common = 2 * xecfg->ctxlen + xecfg->interhunkctxlen;
+ long max_ignorable = xecfg->ctxlen;
+ unsigned long ignored = 0; /* number of ignored blank lines */
+
+ /* remove ignorable changes that are too far before other changes */
+ for (xchp = *xscr; xchp && xchp->ignore; xchp = xchp->next) {
+ xch = xchp->next;
+
+ if (xch == NULL ||
+ xch->i1 - (xchp->i1 + xchp->chg1) >= max_ignorable)
+ *xscr = xch;
+ }
+
+ if (*xscr == NULL)
+ return NULL;
+
+ lxch = *xscr;
+
+ for (xchp = *xscr, xch = xchp->next; xch; xchp = xch, xch = xch->next) {
+ long distance = xch->i1 - (xchp->i1 + xchp->chg1);
+ if (distance > max_common)
+ break;
+
+ if (distance < max_ignorable && (!xch->ignore || lxch == xchp)) {
+ lxch = xch;
+ ignored = 0;
+ } else if (distance < max_ignorable && xch->ignore) {
+ ignored += xch->chg2;
+ } else if (lxch != xchp &&
+ xch->i1 + ignored - (lxch->i1 + lxch->chg1) > max_common) {
+ break;
+ } else if (!xch->ignore) {
+ lxch = xch;
+ ignored = 0;
+ } else {
+ ignored += xch->chg2;
+ }
+ }
+
+ return lxch;
+}
+
+
+static long def_ff(const char *rec, long len, char *buf, long sz, void *priv)
+{
+ if (len > 0 &&
+ (isalpha((unsigned char)*rec) || /* identifier? */
+ *rec == '_' || /* also identifier? */
+ *rec == '$')) { /* identifiers from VMS and other esoterico */
+ if (len > sz)
+ len = sz;
+ while (0 < len && isspace((unsigned char)rec[len - 1]))
+ len--;
+ memcpy(buf, rec, len);
+ return len;
+ }
+ return -1;
+}
+
+static long match_func_rec(xdfile_t *xdf, xdemitconf_t const *xecfg, long ri,
+ char *buf, long sz)
+{
+ const char *rec;
+ long len = xdl_get_rec(xdf, ri, &rec);
+ if (!xecfg->find_func)
+ return def_ff(rec, len, buf, sz, xecfg->find_func_priv);
+ return xecfg->find_func(rec, len, buf, sz, xecfg->find_func_priv);
+}
+
+static int is_func_rec(xdfile_t *xdf, xdemitconf_t const *xecfg, long ri)
+{
+ char dummy[1];
+ return match_func_rec(xdf, xecfg, ri, dummy, sizeof(dummy)) >= 0;
+}
+
+struct func_line {
+ long len;
+ char buf[80];
+};
+
+static long get_func_line(xdfenv_t *xe, xdemitconf_t const *xecfg,
+ struct func_line *func_line, long start, long limit)
+{
+ long l, size, step = (start > limit) ? -1 : 1;
+ char *buf, dummy[1];
+
+ buf = func_line ? func_line->buf : dummy;
+ size = func_line ? sizeof(func_line->buf) : sizeof(dummy);
+
+ for (l = start; l != limit && 0 <= l && l < xe->xdf1.nrec; l += step) {
+ long len = match_func_rec(&xe->xdf1, xecfg, l, buf, size);
+ if (len >= 0) {
+ if (func_line)
+ func_line->len = len;
+ return l;
+ }
+ }
+ return -1;
+}
+
+static int is_empty_rec(xdfile_t *xdf, long ri)
+{
+ const char *rec;
+ long len = xdl_get_rec(xdf, ri, &rec);
+
+ while (len > 0 && XDL_ISSPACE(*rec)) {
+ rec++;
+ len--;
+ }
+ return !len;
+}
+
+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;
+ long funclineprev = -1;
+ struct func_line func_line = { 0 };
+
+ for (xch = xscr; xch; xch = xche->next) {
+ xdchange_t *xchp = xch;
+ xche = xdl_get_hunk(&xch, xecfg);
+ if (!xch)
+ break;
+
+pre_context_calculation:
+ s1 = XDL_MAX(xch->i1 - xecfg->ctxlen, 0);
+ s2 = XDL_MAX(xch->i2 - xecfg->ctxlen, 0);
+
+ if (xecfg->flags & XDL_EMIT_FUNCCONTEXT) {
+ long fs1, i1 = xch->i1;
+
+ /* Appended chunk? */
+ if (i1 >= xe->xdf1.nrec) {
+ long i2 = xch->i2;
+
+ /*
+ * We don't need additional context if
+ * a whole function was added.
+ */
+ while (i2 < xe->xdf2.nrec) {
+ if (is_func_rec(&xe->xdf2, xecfg, i2))
+ goto post_context_calculation;
+ i2++;
+ }
+
+ /*
+ * Otherwise get more context from the
+ * pre-image.
+ */
+ i1 = xe->xdf1.nrec - 1;
+ }
+
+ fs1 = get_func_line(xe, xecfg, NULL, i1, -1);
+ while (fs1 > 0 && !is_empty_rec(&xe->xdf1, fs1 - 1) &&
+ !is_func_rec(&xe->xdf1, xecfg, fs1 - 1))
+ fs1--;
+ if (fs1 < 0)
+ fs1 = 0;
+ if (fs1 < s1) {
+ s2 = XDL_MAX(s2 - (s1 - fs1), 0);
+ s1 = fs1;
+
+ /*
+ * Did we extend context upwards into an
+ * ignored change?
+ */
+ while (xchp != xch &&
+ xchp->i1 + xchp->chg1 <= s1 &&
+ xchp->i2 + xchp->chg2 <= s2)
+ xchp = xchp->next;
+
+ /* If so, show it after all. */
+ if (xchp != xch) {
+ xch = xchp;
+ goto pre_context_calculation;
+ }
+ }
+ }
+
+ post_context_calculation:
+ 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;
+
+ if (xecfg->flags & XDL_EMIT_FUNCCONTEXT) {
+ long fe1 = get_func_line(xe, xecfg, NULL,
+ xche->i1 + xche->chg1,
+ xe->xdf1.nrec);
+ while (fe1 > 0 && is_empty_rec(&xe->xdf1, fe1 - 1))
+ fe1--;
+ if (fe1 < 0)
+ fe1 = xe->xdf1.nrec;
+ if (fe1 > e1) {
+ e2 = XDL_MIN(e2 + (fe1 - e1), xe->xdf2.nrec);
+ e1 = fe1;
+ }
+
+ /*
+ * Overlap with next change? Then include it
+ * in the current hunk and start over to find
+ * its new end.
+ */
+ if (xche->next) {
+ long l = XDL_MIN(xche->next->i1,
+ xe->xdf1.nrec - 1);
+ if (l - xecfg->ctxlen <= e1 ||
+ get_func_line(xe, xecfg, NULL, l, e1) < 0) {
+ xche = xche->next;
+ goto post_context_calculation;
+ }
+ }
+ }
+
+ /*
+ * Emit current hunk header.
+ */
+
+ if (xecfg->flags & XDL_EMIT_FUNCNAMES) {
+ get_func_line(xe, xecfg, &func_line,
+ s1 - 1, funclineprev);
+ funclineprev = s1 - 1;
+ }
+ if (xdl_emit_hunk_hdr(s1 + 1, e1 - s1, s2 + 1, e2 - s2,
+ func_line.buf, func_line.len, ecb) < 0)
+ return -1;
+
+ /*
+ * Emit pre-context.
+ */
+ for (; s2 < xch->i2; s2++)
+ if (xdl_emit_record(&xe->xdf2, s2, " ", 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->xdf2, s2, " ", 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 (s2 = xche->i2 + xche->chg2; s2 < e2; s2++)
+ if (xdl_emit_record(&xe->xdf2, s2, " ", ecb) < 0)
+ return -1;
+ }
+
+ return 0;
+}
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