add strbuf_adddup()

diff --git a/strbuf.c b/strbuf.c
index 536b43204e228a8b7ec8fc3fb44c555157253f8c..dbd8c4bcfb2f8549b8713a8d9fbbfd8adcd0088c 100644 (file)
--- a/strbuf.c
+++ b/strbuf.c
@@ -106,6 +106,13 @@ void strbuf_add(struct strbuf *sb, const void *data, size_t len)
        strbuf_setlen(sb, sb->len + len);
 }
 
+void strbuf_adddup(struct strbuf *sb, size_t pos, size_t len)
+{
+       strbuf_grow(sb, len);
+       memcpy(sb->buf + sb->len, sb->buf + pos, len);
+       strbuf_setlen(sb, sb->len + len);
+}
+
 void strbuf_addf(struct strbuf *sb, const char *fmt, ...)
 {
        int len;