From c4ac476c90b422ee876ee7e53ed942d693943bea Mon Sep 17 00:00:00 2001
From: Stefano Sabatini <stefasab@gmail.com>
Date: Sun, 18 Apr 2021 22:49:25 +0200
Subject: [PATCH 1/3] lavf/avio: add avio_vprintf()

This new function makes it possible to use avio_printf() functionality from
a function taking a variable list of arguments.
---
 doc/APIchanges        |  3 +++
 libavformat/avio.h    |  6 ++++++
 libavformat/aviobuf.c | 17 +++++++++++++----
 libavformat/version.h |  2 +-
 4 files changed, 23 insertions(+), 5 deletions(-)

diff --git a/doc/APIchanges b/doc/APIchanges
index 1a9f0a303e..c2612efb93 100644
--- a/doc/APIchanges
+++ b/doc/APIchanges
@@ -13,6 +13,9 @@ libavutil:     2021-04-27
 
 
 API changes, most recent first:
+2022-04-03 - xxxxxxxxxx - lavf 59.21.100 - avio.h
+  Add avio_vprintf(), similar to avio_printf() but allow to use it
+  from within a function taking a variable argument list as input.
 
 2022-03-16 - xxxxxxxxxx - all libraries - version_major.h
   Add lib<name>/version_major.h as new installed headers, which only
diff --git a/libavformat/avio.h b/libavformat/avio.h
index 3ed9175a9b..36c3d7b430 100644
--- a/libavformat/avio.h
+++ b/libavformat/avio.h
@@ -519,6 +519,12 @@ int64_t avio_size(AVIOContext *s);
  */
 int avio_feof(AVIOContext *s);
 
+/**
+ * Writes a formatted string to the context taking a va_list.
+ * @return number of bytes written, < 0 on error.
+ */
+int avio_vprintf(AVIOContext *s, const char *fmt, va_list ap);
+
 /**
  * Writes a formatted string to the context.
  * @return number of bytes written, < 0 on error.
diff --git a/libavformat/aviobuf.c b/libavformat/aviobuf.c
index 29d4bd7510..64184978c2 100644
--- a/libavformat/aviobuf.c
+++ b/libavformat/aviobuf.c
@@ -1289,15 +1289,12 @@ int avio_closep(AVIOContext **s)
     return ret;
 }
 
-int avio_printf(AVIOContext *s, const char *fmt, ...)
+int avio_vprintf(AVIOContext *s, const char *fmt, va_list ap)
 {
-    va_list ap;
     AVBPrint bp;
 
     av_bprint_init(&bp, 0, INT_MAX);
-    va_start(ap, fmt);
     av_vbprintf(&bp, fmt, ap);
-    va_end(ap);
     if (!av_bprint_is_complete(&bp)) {
         av_bprint_finalize(&bp, NULL);
         s->error = AVERROR(ENOMEM);
@@ -1308,6 +1305,18 @@ int avio_printf(AVIOContext *s, const char *fmt, ...)
     return bp.len;
 }
 
+int avio_printf(AVIOContext *s, const char *fmt, ...)
+{
+    va_list ap;
+    int ret;
+
+    va_start(ap, fmt);
+    ret = avio_vprintf(s, fmt, ap);
+    va_end(ap);
+
+    return ret;
+}
+
 void avio_print_string_array(AVIOContext *s, const char *strings[])
 {
     for(; *strings; strings++)
diff --git a/libavformat/version.h b/libavformat/version.h
index f4a26c2870..2f54f57c02 100644
--- a/libavformat/version.h
+++ b/libavformat/version.h
@@ -31,7 +31,7 @@
 
 #include "version_major.h"
 
-#define LIBAVFORMAT_VERSION_MINOR  20
+#define LIBAVFORMAT_VERSION_MINOR  21
 #define LIBAVFORMAT_VERSION_MICRO 101
 
 #define LIBAVFORMAT_VERSION_INT AV_VERSION_INT(LIBAVFORMAT_VERSION_MAJOR, \
-- 
2.25.1