avformat/avio: add avio_print_string_array and avio_print

These functions can be used to print a variable number of strings consecutively
to the IO context. Unlike av_bprintf, no temporary buffer is necessary.

Signed-off-by: Marton Balint <cus@passwd.hu>

1 files changed, 17 insertions, 0 deletions

diff --git a/libavformat/avio.h b/libavformat/avio.h
index dcb8dcdf93..910e4f1b48 100644
--- a/libavformat/avio.h
+++ b/libavformat/avio.h
@@ -575,6 +575,23 @@ int avio_feof(AVIOContext *s);
 int avio_printf(AVIOContext *s, const char *fmt, ...) av_printf_format(2, 3);
 
 /**
+ * Write a NULL terminated array of strings to the context.
+ * Usually you don't need to use this function directly but its macro wrapper,
+ * avio_print.
+ */
+void avio_print_string_array(AVIOContext *s, const char *strings[]);
+
+/**
+ * Write strings (const char *) to the context.
+ * This is a convenience macro around avio_print_string_array and it
+ * automatically creates the string array from the variable argument list.
+ * For simple string concatenations this function is more performant than using
+ * avio_printf since it does not need a temporary buffer.
+ */
+#define avio_print(s, ...) \
+    avio_print_string_array(s, (const char*[]){__VA_ARGS__, NULL})
+
+/**
  * Force flushing of buffered data.
  *
  * For write streams, force the buffered data to be immediately written to the output,