1 files changed, 61 insertions, 0 deletions
diff --git a/util/sbase/libutil/strnsubst.c b/util/sbase/libutil/strnsubst.c
new file mode 100644
index 00000000..2da54aba
--- /dev/null
+++ b/util/sbase/libutil/strnsubst.c
@@ -0,0 +1,61 @@
+/*
+ * Copyright (c) 2002 J. Mallett.  All rights reserved.
+ * You may do whatever you want with this file as long as
+ * the above copyright and this notice remain intact, along
+ * with the following statement:
+ * 	For the man who taught me vi, and who got too old, too young.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+
+#include "../util.h"
+
+/*
+ * Replaces str with a string consisting of str with match replaced with
+ * replstr as many times as can be done before the constructed string is
+ * maxsize bytes large.  It does not free the string pointed to by str, it
+ * is up to the calling program to be sure that the original contents of
+ * str as well as the new contents are handled in an appropriate manner.
+ * If replstr is NULL, then that internally is changed to a nil-string, so
+ * that we can still pretend to do somewhat meaningful substitution.
+ * No value is returned.
+ */
+void
+strnsubst(char **str, const char *match, const char *replstr, size_t maxsize)
+{
+	char *s1, *s2, *this;
+	size_t matchlen, s2len;
+	int n;
+
+	if ((s1 = *str) == NULL)
+		return;
+	s2 = emalloc(maxsize);
+
+	if (replstr == NULL)
+		replstr = "";
+
+	if (match == NULL || *match == '\0' || strlen(s1) >= maxsize) {
+		strlcpy(s2, s1, maxsize);
+		goto done;
+	}
+
+	*s2 = '\0';
+	s2len = 0;
+	matchlen = strlen(match);
+	for (;;) {
+		if ((this = strstr(s1, match)) == NULL)
+			break;
+		n = snprintf(s2 + s2len, maxsize - s2len, "%.*s%s",
+		    (int)(this - s1), s1, replstr);
+		if (n == -1 || n + s2len + strlen(this + matchlen) >= maxsize)
+			break;			/* out of room */
+		s2len += n;
+		s1 = this + matchlen;
+	}
+	strlcpy(s2 + s2len, s1, maxsize - s2len);
+done:
+	*str = s2;
+	return;
+}