ffmpeg | branch: master | Andreas Rheinhardt <andreas.rheinha...@gmail.com> | Wed Apr 15 04:05:09 2020 +0200| [112afaccdfa56e446527f0303f3e1277bc34b500] | committer: Andreas Rheinhardt
avformat/matroskaenc: Refactor writing EBML lengths This commit factors the ability to write ordinary EBML numbers out of the functions for writing EBML lengths. This is in preparation for future commits. Signed-off-by: Andreas Rheinhardt <andreas.rheinha...@gmail.com> > http://git.videolan.org/gitweb.cgi/ffmpeg.git/?a=commit;h=112afaccdfa56e446527f0303f3e1277bc34b500 --- libavformat/matroskaenc.c | 36 ++++++++++++++++++++++++++---------- 1 file changed, 26 insertions(+), 10 deletions(-) diff --git a/libavformat/matroskaenc.c b/libavformat/matroskaenc.c index 3408b49a81..d3c6a7ea9b 100644 --- a/libavformat/matroskaenc.c +++ b/libavformat/matroskaenc.c @@ -190,19 +190,38 @@ static void put_ebml_size_unknown(AVIOContext *pb, int bytes) } /** - * Calculate how many bytes are needed to represent the length field - * of an EBML element whose payload has a given length. + * Returns how many bytes are needed to represent a number + * as EBML variable length integer. */ -static int ebml_length_size(uint64_t length) +static int ebml_num_size(uint64_t num) { int bytes = 0; - length++; do { bytes++; - } while (length >>= 7); + } while (num >>= 7); return bytes; } +/** + * Calculate how many bytes are needed to represent the length field + * of an EBML element whose payload has a given length. + */ +static int ebml_length_size(uint64_t length) +{ + return ebml_num_size(length + 1); +} + +/** + * Write a number as EBML variable length integer on `bytes` bytes. + * `bytes` is taken literally without checking. + */ +static void put_ebml_num(AVIOContext *pb, uint64_t num, int bytes) +{ + num |= 1ULL << bytes * 7; + for (int i = bytes - 1; i >= 0; i--) + avio_w8(pb, (uint8_t)(num >> i * 8)); +} + /** * Write a length as EBML variable length integer. * @@ -211,7 +230,7 @@ static int ebml_length_size(uint64_t length) */ static void put_ebml_length(AVIOContext *pb, uint64_t length, int bytes) { - int i, needed_bytes = ebml_length_size(length); + int needed_bytes = ebml_length_size(length); // sizes larger than this are currently undefined in EBML av_assert0(length < (1ULL << 56) - 1); @@ -221,10 +240,7 @@ static void put_ebml_length(AVIOContext *pb, uint64_t length, int bytes) // The bytes needed to write the given size must not exceed // the bytes that we ought to use. av_assert0(bytes >= needed_bytes); - - length |= 1ULL << bytes * 7; - for (i = bytes - 1; i >= 0; i--) - avio_w8(pb, (uint8_t)(length >> i * 8)); + put_ebml_num(pb, length, bytes); } /** _______________________________________________ ffmpeg-cvslog mailing list ffmpeg-cvslog@ffmpeg.org https://ffmpeg.org/mailman/listinfo/ffmpeg-cvslog To unsubscribe, visit link above, or email ffmpeg-cvslog-requ...@ffmpeg.org with subject "unsubscribe".
