From: Andreas Weis <git...@ghulbus-inc.de>
The new function behaves the same as av_log_format_line, but also forwards
the return value from the underlying snprintf call. This will allow
callers to accurately determine the size requirements for the line buffer.
Signed-off-by: Andreas Weis <git...@ghulbus-inc.de>
---
libavutil/log.c | 11 ++++++++++-
libavutil/log.h | 17 +++++++++++++++++
2 files changed, 27 insertions(+), 1 deletion(-)
diff --git a/libavutil/log.c b/libavutil/log.c
index 4583519..0efba7a 100644
--- a/libavutil/log.c
+++ b/libavutil/log.c
@@ -284,10 +284,19 @@ static void format_line(void *avcl, int level, const char
*fmt, va_list vl,
void av_log_format_line(void *ptr, int level, const char *fmt, va_list vl,
char *line, int line_size, int *print_prefix)
{
+ av_log_format_line2(ptr, level, fmt, vl, line, line_size, print_prefix);
+}
+
+int av_log_format_line2(void *ptr, int level, const char *fmt, va_list vl,
+ char *line, int line_size, int *print_prefix)
+{
AVBPrint part[4];
+ int ret;
+
format_line(ptr, level, fmt, vl, part, print_prefix, NULL);
- snprintf(line, line_size, "%s%s%s%s", part[0].str, part[1].str,
part[2].str, part[3].str);
+ ret = snprintf(line, line_size, "%s%s%s%s", part[0].str, part[1].str,
part[2].str, part[3].str);
av_bprint_finalize(part+3, NULL);
+ return ret;
}
void av_log_default_callback(void* ptr, int level, const char* fmt, va_list vl)
diff --git a/libavutil/log.h b/libavutil/log.h
index 321748c..9b1d66f 100644
--- a/libavutil/log.h
+++ b/libavutil/log.h
@@ -317,6 +317,23 @@ AVClassCategory av_default_get_category(void *ptr);
void av_log_format_line(void *ptr, int level, const char *fmt, va_list vl,
char *line, int line_size, int *print_prefix);
+/**
+ * Format a line of log the same way as the default callback.
+ * @param line buffer to receive the formatted line;
+ * may be NULL if line_size is 0
+ * @param line_size size of the buffer; at most line_size-1 characters will
+ * be written to the buffer, plus one null terminator
+ * @param print_prefix used to store whether the prefix must be printed;
+ * must point to a persistent integer initially set to 1
+ * @return Returns a negative value if an error occured, otherwise returns
+ * the number of characters that would have been written for a
+ * sufficiently large buffer, not including the terminating null
+ * character. If the return value is not less than line_size, it means
+ * that the log message was truncated to fit the buffer.
+ */
+int av_log_format_line2(void *ptr, int level, const char *fmt, va_list vl,
+ char *line, int line_size, int *print_prefix);
+
#if FF_API_DLOG
/**
* av_dlog macros
--
2.5.0.windows.1
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