strbuf.c: add `strbuf_insertf()` and `strbuf_vinsertf()`

Implement `strbuf_insertf()` and `strbuf_vinsertf()` to
insert data using a printf format string.

Original-idea-by: Johannes Schindelin <johannes.schindelin@gmx.de>
Signed-off-by: Paul-Sebastian Ungureanu <ungureanupaulsebastian@gmail.com>
Helped-by: Johannes Sixt <j6t@kdbg.org>
Signed-off-by: Thomas Gummerer <t.gummerer@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

1 files changed, 9 insertions, 0 deletions

diff --git a/strbuf.h b/strbuf.h
index be02150..8f8fe01 100644
--- a/strbuf.h
+++ b/strbuf.h
@@ -245,6 +245,15 @@ void strbuf_addchars(struct strbuf *sb, int c, size_t n);
 void strbuf_insert(struct strbuf *sb, size_t pos, const void *, size_t);
 
 /**
+ * Insert data to the given position of the buffer giving a printf format
+ * string. The contents will be shifted, not overwritten.
+ */
+void strbuf_vinsertf(struct strbuf *sb, size_t pos, const char *fmt,
+		     va_list ap);
+
+void strbuf_insertf(struct strbuf *sb, size_t pos, const char *fmt, ...);
+
+/**
  * Remove given amount of data from a given position of the buffer.
  */
 void strbuf_remove(struct strbuf *sb, size_t pos, size_t len);