1 files changed, 57 insertions, 2 deletions

diff --git a/membuffer.c b/membuffer.c
index c8a06662f..2889a0cdc 100644
--- a/membuffer.c
+++ b/membuffer.c
@@ -6,12 +6,18 @@
 #include "dive.h"
 #include "membuffer.h"
 
-void free_buffer(struct membuffer *b)
+char *detach_buffer(struct membuffer *b)
 {
-	free(b->buffer);
+	char *result = b->buffer;
 	b->buffer = NULL;
 	b->len = 0;
 	b->alloc = 0;
+	return result;
+}
+
+void free_buffer(struct membuffer *b)
+{
+	free(detach_buffer(b));
 }
 
 void flush_buffer(struct membuffer *b, FILE *f)
@@ -100,6 +106,26 @@ void put_vformat(struct membuffer *b, const char *fmt, va_list args)
 	}
 }
 
+/* Silly helper using membuffer */
+char *vformat_string(const char *fmt, va_list args)
+{
+	struct membuffer mb = { 0 };
+	put_vformat(&mb, fmt, args);
+	mb_cstring(&mb);
+	return detach_buffer(&mb);
+}
+
+char *format_string(const char *fmt, ...)
+{
+	va_list args;
+	char *result;
+
+	va_start(args, fmt);
+	result = vformat_string(fmt, args);
+	va_end(args);
+	return result;
+}
+
 void put_format(struct membuffer *b, const char *fmt, ...)
 {
 	va_list args;
@@ -228,3 +254,32 @@ void put_quoted(struct membuffer *b, const char *text, int is_attribute, int is_
 		text = p;
 	}
 }
+
+char *add_to_string_va(const char *old, const char *fmt, va_list args)
+{
+	char *res;
+	struct membuffer o = { 0 }, n = { 0 };
+	put_vformat(&n, fmt, args);
+	put_format(&o, "%s\n%s", old ?: "", mb_cstring(&n));
+	res = strdup(mb_cstring(&o));
+	free_buffer(&o);
+	free_buffer(&n);
+	free((void *)old);
+	return res;
+}
+
+/* this is a convenience function that cleverly adds text to a string, using our membuffer
+ * infrastructure.
+ * WARNING - this will free(old), the intended pattern is
+ * string = add_to_string(string, fmt, ...)
+ */
+char *add_to_string(const char *old, const char *fmt, ...)
+{
+	char *res;
+	va_list args;
+
+	va_start(args, fmt);
+	res = add_to_string_va(old, fmt, args);
+	va_end(args);
+	return res;
+}