Add regular expression support for the format search, match and

substitute modifiers.

1 files changed, 98 insertions, 0 deletions

diff --git a/regsub.c b/regsub.c
new file mode 100644
index 00000000..53c83a8f
--- /dev/null
+++ b/regsub.c
@@ -0,0 +1,98 @@
+/* $OpenBSD$ */
+
+/*
+ * 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];
+	size_t		 start, end, len = 0;
+	char		*buf = NULL;
+
+	if (*text == '\0')
+		return (xstrdup(""));
+	if (regcomp(&r, pattern, flags) != 0)
+		return (NULL);
+
+	start = 0;
+	end = strlen(text);
+
+	while (start != end) {
+		m[0].rm_so = start;
+		m[0].rm_eo = end;
+
+		if (regexec(&r, text, nitems(m), m, REG_STARTEND) != 0) {
+			regsub_copy(&buf, &len, text, start, end);
+			break;
+		}
+		if (m[0].rm_so == m[0].rm_eo) {
+			regsub_copy(&buf, &len, text, start, end);
+			break;
+		}
+
+		regsub_copy(&buf, &len, text, start, m[0].rm_so);
+		regsub_expand(&buf, &len, with, text, m, nitems(m));
+		start = m[0].rm_eo;
+	}
+	buf[len] = '\0';
+
+	regfree(&r);
+	return (buf);
+}