[FFmpeg-devel] Re: [PATCH] avutil/bprint: fix av_bprint_strftime with %p format string reporting truncated output (PR #20330)

[Marton Balint via ffmpeg-devel]

On Tue, 26 Aug 2025, Nicolas George via ffmpeg-devel wrote:

Marton Balint via ffmpeg-devel (HE12025-08-24):
From f8e83bce6269c95fbad90f34434ceb641bf753d5 Mon Sep 17 00:00:00 2001
From: Marton Balint <c...@passwd.hu>
Date: Sun, 24 Aug 2025 21:42:54 +0200
Subject: [PATCH 1/2] avutil/bprint: make av_bprintf use av_vbprintf

No reason to duplicate the code.

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

No objection.

---
 libavutil/bprint.c | 33 +++++++++------------------------
 1 file changed, 9 insertions(+), 24 deletions(-)

diff --git a/libavutil/bprint.c b/libavutil/bprint.c
index 4e9571715c..932c03ce50 100644
--- a/libavutil/bprint.c
+++ b/libavutil/bprint.c
@@ -96,35 +96,12 @@ void av_bprint_init_for_buffer(AVBPrint *buf, char *buffer, 
unsigned size)
     *buf->str = 0;
 }

-void av_bprintf(AVBPrint *buf, const char *fmt, ...)
-{
-    unsigned room;
-    char *dst;
-    va_list vl;
-    int extra_len;
-
-    while (1) {
-        room = av_bprint_room(buf);
-        dst = room ? buf->str + buf->len : NULL;
-        va_start(vl, fmt);
-        extra_len = vsnprintf(dst, room, fmt, vl);
-        va_end(vl);
-        if (extra_len <= 0)
-            return;
-        if (extra_len < room)
-            break;
-        if (av_bprint_alloc(buf, extra_len))
-            break;
-    }
-    av_bprint_grow(buf, extra_len);
-}
-
 void av_vbprintf(AVBPrint *buf, const char *fmt, va_list vl_arg)
 {
     unsigned room;
     char *dst;

-    int extra_len;
     va_list vl;
+    int extra_len;

Uh?

This change is diff-algorithm dependant, but I have already force pushed a 
new version which gets rid of this.



     while (1) {
         room = av_bprint_room(buf);
@@ -142,6 +119,14 @@ void av_vbprintf(AVBPrint *buf, const char *fmt, va_list 
vl_arg)
     av_bprint_grow(buf, extra_len);
 }

+void av_bprintf(AVBPrint *buf, const char *fmt, ...)
+{
+    va_list vl;
+    va_start(vl, fmt);
+    av_vbprintf(buf, fmt, vl);
+    va_end(vl);
+}
+
 void av_bprint_chars(AVBPrint *buf, char c, unsigned n)
 {
     unsigned room, real_n;

Regards,

Thanks,
Marton
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