summaryrefslogtreecommitdiffstats
path: root/regsub.c
diff options
context:
space:
mode:
Diffstat (limited to 'regsub.c')
-rw-r--r--regsub.c120
1 files changed, 120 insertions, 0 deletions
diff --git a/regsub.c b/regsub.c
new file mode 100644
index 0000000..4039b9b
--- /dev/null
+++ b/regsub.c
@@ -0,0 +1,120 @@
+/* $OpenBSD$ */
+
+/*
+ * Copyright (c) 2019 Nicholas Marriott <nicholas.marriott@gmail.com>
+ *
+ * Permission to use, copy, modify, and distribute this software for any
+ * purpose with or without fee is hereby granted, provided that the above
+ * copyright notice and this permission notice appear in all copies.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL WARRANTIES
+ * WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR
+ * ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF MIND, USE, DATA OR PROFITS, WHETHER
+ * IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING
+ * OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ */
+
+#include <sys/types.h>
+
+#include <regex.h>
+#include <string.h>
+
+#include "tmux.h"
+
+static void
+regsub_copy(char **buf, size_t *len, const char *text, size_t start, size_t end)
+{
+ size_t add = end - start;
+
+ *buf = xrealloc(*buf, (*len) + add + 1);
+ memcpy((*buf) + *len, text + start, add);
+ (*len) += add;
+}
+
+static void
+regsub_expand(char **buf, size_t *len, const char *with, const char *text,
+ regmatch_t *m, u_int n)
+{
+ const char *cp;
+ u_int i;
+
+ for (cp = with; *cp != '\0'; cp++) {
+ if (*cp == '\\') {
+ cp++;
+ if (*cp >= '0' && *cp <= '9') {
+ i = *cp - '0';
+ if (i < n && m[i].rm_so != m[i].rm_eo) {
+ regsub_copy(buf, len, text, m[i].rm_so,
+ m[i].rm_eo);
+ continue;
+ }
+ }
+ }
+ *buf = xrealloc(*buf, (*len) + 2);
+ (*buf)[(*len)++] = *cp;
+ }
+}
+
+char *
+regsub(const char *pattern, const char *with, const char *text, int flags)
+{
+ regex_t r;
+ regmatch_t m[10];
+ ssize_t start, end, last, len = 0;
+ int empty = 0;
+ char *buf = NULL;
+
+ if (*text == '\0')
+ return (xstrdup(""));
+ if (regcomp(&r, pattern, flags) != 0)
+ return (NULL);
+
+ start = 0;
+ last = 0;
+ end = strlen(text);
+
+ while (start <= end) {
+ if (regexec(&r, text + start, nitems(m), m, 0) != 0) {
+ regsub_copy(&buf, &len, text, start, end);
+ break;
+ }
+
+ /*
+ * Append any text not part of this match (from the end of the
+ * last match).
+ */
+ regsub_copy(&buf, &len, text, last, m[0].rm_so + start);
+
+ /*
+ * If the last match was empty and this one isn't (it is either
+ * later or has matched text), expand this match. If it is
+ * empty, move on one character and try again from there.
+ */
+ if (empty ||
+ start + m[0].rm_so != last ||
+ m[0].rm_so != m[0].rm_eo) {
+ regsub_expand(&buf, &len, with, text + start, m,
+ nitems(m));
+
+ last = start + m[0].rm_eo;
+ start += m[0].rm_eo;
+ empty = 0;
+ } else {
+ last = start + m[0].rm_eo;
+ start += m[0].rm_eo + 1;
+ empty = 1;
+ }
+
+ /* Stop now if anchored to start. */
+ if (*pattern == '^') {
+ regsub_copy(&buf, &len, text, start, end);
+ break;
+ }
+ }
+ buf[len] = '\0';
+
+ regfree(&r);
+ return (buf);
+}