Ensure the input is <= 31 bits because otherwise it would produce
very invalid UTF-8.
Document that the length can be up to 6 bytes, because that is what
the code does. The FLAC encoder abuses UTF-8 to store 32-bits
integers, limiting PUT_UTF8() to 21 bits might affect some real
cases negatively.
Signed-off-by: Nicolas George <geo...@nsup.org>
---
libavutil/common.h | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/libavutil/common.h b/libavutil/common.h
index fd1404be6c..7a71be3c81 100644
--- a/libavutil/common.h
+++ b/libavutil/common.h
@@ -505,7 +505,9 @@ static av_always_inline av_const int av_parity_c(uint32_t v)
/**
* @def PUT_UTF8(val, tmp, PUT_BYTE)
- * Convert a 32-bit Unicode character to its UTF-8 encoded form (up to 4 bytes
long).
+ * Convert a 32-bit Unicode character to its UTF-8 encoded form (up to 6
+ * bytes long, but codes more than 4 bytes long, i.e. codepoints above
+ * 0x001FFFFF, are deprecated).
* @param val is an input-only argument and should be of type uint32_t. It
holds
* a UCS-4 encoded Unicode character that is to be converted to UTF-8. If
* val is given as a function it is executed only once.
@@ -522,7 +524,7 @@ static av_always_inline av_const int av_parity_c(uint32_t v)
#define PUT_UTF8(val, tmp, PUT_BYTE)\
{\
int bytes, shift;\
- uint32_t in = val;\
+ uint32_t in = val & 0x7FFFFFFF;\
if (in < 0x80) {\
tmp = in;\
PUT_BYTE\
--
2.35.1
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