mirror of
https://github.com/FFmpeg/FFmpeg.git
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lavc/bitstream: templatize for BE/LE
Allows using both BE and LE bitstream readers in the same file.
This commit is contained in:
Anton Khirnov
parent
8fe551eca0
commit
9177970bca
@ -1252,6 +1252,7 @@ SKIPHEADERS += %_tablegen.h \
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aaccoder_trellis.h \
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aacenc_quantization.h \
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aacenc_quantization_misc.h \
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bitstream_template.h \
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$(ARCH)/vpx_arith.h \
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SKIPHEADERS-$(CONFIG_AMF) += amfenc.h
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@ -23,6 +23,21 @@
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* bitstream reader API header.
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*/
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/*
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* Bit order (endianness) is controlled by #defining BITSTREAM_BE and/or
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* BITSTREAM_LE before #including this header. The corresponding bitreading
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* functions are provided as bits_*_be()/bits_*_le() respectively.
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*
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* If neither or only BITSTREAM_BE is defined, then the default (unsuffixed)
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* bits_*() will resolve to the big-endian implementation. If only BITSTREAM_LE
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* is defined, little-endian will be the default.
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*
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* If both are defined, then the default can be controlled by defining at most
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* one of BITSTREAM_DEFAULT_LE/BE. When BITSTREAM_DEFAULT_* is not defined, no
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* default is provided and you must always explicitly use the _be() or _le()
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* variants.
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*/
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#ifndef AVCODEC_BITSTREAM_H
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#define AVCODEC_BITSTREAM_H
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@ -42,461 +57,80 @@
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#define UNCHECKED_BITSTREAM_READER !CONFIG_SAFE_BITSTREAM_READER
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#endif
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typedef struct BitstreamContext {
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uint64_t bits; // stores bits read from the buffer
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const uint8_t *buffer, *buffer_end;
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const uint8_t *ptr; // pointer to the position inside a buffer
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unsigned bits_valid; // number of bits left in bits field
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unsigned size_in_bits;
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} BitstreamContext;
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// select the default endianness, if any
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#if defined(BITSTREAM_LE) && defined(BITSTREAM_BE)
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/**
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* @return
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* - 0 on successful refill
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* - a negative number when bitstream end is hit
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*
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* Always succeeds when UNCHECKED_BITSTREAM_READER is enabled.
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*/
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static inline int bits_priv_refill_64(BitstreamContext *bc)
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{
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#if !UNCHECKED_BITSTREAM_READER
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if (bc->ptr >= bc->buffer_end)
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return -1;
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# if defined(BITSTREAM_DEFAULT_BE) && defined(BITSTREAM_DEFAULT_LE)
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# error "At most one of BITSTREAM_DEFAULT_BE/LE must be defined"
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# elif defined(BITSTREAM_DEFAULT_BE)
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# define BITS_DEFAULT_BE
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# elif defined(BITSTREAM_DEFAULT_LE)
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# define BITS_DEFAULT_LE
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# endif
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#elif defined(BITSTREAM_LE)
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# define BITS_DEFAULT_LE
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#else // select BE if nothing is requested explicitly
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# define BITS_DEFAULT_BE
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# define BITSTREAM_WANT_BE
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#endif
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#ifdef BITSTREAM_READER_LE
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bc->bits = AV_RL64(bc->ptr);
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#else
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bc->bits = AV_RB64(bc->ptr);
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#endif
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bc->ptr += 8;
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bc->bits_valid = 64;
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#if defined(BITS_DEFAULT_LE)
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return 0;
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}
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# define BitstreamContext BitstreamContextLE
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# define bits_init bits_init_le
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# define bits_init8 bits_init8_le
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# define bits_tell bits_tell_le
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# define bits_size bits_size_le
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# define bits_left bits_left_le
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# define bits_read_bit bits_read_bit_le
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# define bits_read_nz bits_read_nz_le
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# define bits_read bits_read_le
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# define bits_read_63 bits_read_63_le
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# define bits_read_64 bits_read_64_le
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# define bits_read_signed bits_read_signed_le
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# define bits_peek_nz bits_peek_nz_le
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# define bits_peek bits_peek_le
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# define bits_peek_signed bits_peek_signed_le
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# define bits_skip bits_skip_le
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# define bits_seek bits_seek_le
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# define bits_align bits_align_le
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# define bits_read_xbits bits_read_xbits_le
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# define bits_decode012 bits_decode012_le
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# define bits_decode210 bits_decode210_le
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# define bits_apply_sign bits_apply_sign_le
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# define bits_read_vlc bits_read_vlc_le
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#elif defined(BITS_DEFAULT_BE)
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# define BitstreamContext BitstreamContextBE
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# define bits_init bits_init_be
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# define bits_init8 bits_init8_be
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# define bits_tell bits_tell_be
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# define bits_size bits_size_be
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# define bits_left bits_left_be
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# define bits_read_bit bits_read_bit_be
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# define bits_read_nz bits_read_nz_be
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# define bits_read bits_read_be
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# define bits_read_63 bits_read_63_be
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# define bits_read_64 bits_read_64_be
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# define bits_read_signed bits_read_signed_be
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# define bits_peek_nz bits_peek_nz_be
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# define bits_peek bits_peek_be
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# define bits_peek_signed bits_peek_signed_be
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# define bits_skip bits_skip_be
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# define bits_seek bits_seek_be
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# define bits_align bits_align_be
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# define bits_read_xbits bits_read_xbits_be
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# define bits_decode012 bits_decode012_be
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# define bits_decode210 bits_decode210_be
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# define bits_apply_sign bits_apply_sign_be
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# define bits_read_vlc bits_read_vlc_be
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/**
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* @return
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* - 0 on successful refill
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* - a negative number when bitstream end is hit
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*
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* Always succeeds when UNCHECKED_BITSTREAM_READER is enabled.
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*/
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static inline int bits_priv_refill_32(BitstreamContext *bc)
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{
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#if !UNCHECKED_BITSTREAM_READER
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if (bc->ptr >= bc->buffer_end)
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return -1;
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#endif
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#ifdef BITSTREAM_READER_LE
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bc->bits |= (uint64_t)AV_RL32(bc->ptr) << bc->bits_valid;
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#else
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bc->bits |= (uint64_t)AV_RB32(bc->ptr) << (32 - bc->bits_valid);
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#endif
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bc->ptr += 4;
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bc->bits_valid += 32;
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return 0;
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}
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/**
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* Initialize BitstreamContext.
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* @param buffer bitstream buffer, must be AV_INPUT_BUFFER_PADDING_SIZE bytes
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* larger than the actual read bits because some optimized bitstream
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* readers read 32 or 64 bits at once and could read over the end
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* @param bit_size the size of the buffer in bits
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* @return 0 on success, AVERROR_INVALIDDATA if the buffer_size would overflow.
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*/
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static inline int bits_init(BitstreamContext *bc, const uint8_t *buffer,
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unsigned int bit_size)
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{
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unsigned int buffer_size;
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if (bit_size > INT_MAX - 7 || !buffer) {
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bc->buffer = NULL;
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bc->ptr = NULL;
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bc->bits_valid = 0;
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return AVERROR_INVALIDDATA;
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}
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buffer_size = (bit_size + 7) >> 3;
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bc->buffer = buffer;
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bc->buffer_end = buffer + buffer_size;
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bc->ptr = bc->buffer;
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bc->size_in_bits = bit_size;
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bc->bits_valid = 0;
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bc->bits = 0;
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bits_priv_refill_64(bc);
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return 0;
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}
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/**
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* Initialize BitstreamContext.
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* @param buffer bitstream buffer, must be AV_INPUT_BUFFER_PADDING_SIZE bytes
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* larger than the actual read bits because some optimized bitstream
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* readers read 32 or 64 bits at once and could read over the end
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* @param byte_size the size of the buffer in bytes
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* @return 0 on success, AVERROR_INVALIDDATA if the buffer_size would overflow
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*/
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static inline int bits_init8(BitstreamContext *bc, const uint8_t *buffer,
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unsigned int byte_size)
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{
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if (byte_size > INT_MAX / 8)
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return AVERROR_INVALIDDATA;
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return bits_init(bc, buffer, byte_size * 8);
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}
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/**
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* Return number of bits already read.
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*/
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static inline int bits_tell(const BitstreamContext *bc)
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{
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return (bc->ptr - bc->buffer) * 8 - bc->bits_valid;
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}
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/**
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* Return buffer size in bits.
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*/
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static inline int bits_size(const BitstreamContext *bc)
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{
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return bc->size_in_bits;
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}
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/**
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* Return the number of the bits left in a buffer.
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*/
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static inline int bits_left(const BitstreamContext *bc)
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{
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return (bc->buffer - bc->ptr) * 8 + bc->size_in_bits + bc->bits_valid;
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}
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static inline uint64_t bits_priv_val_show(BitstreamContext *bc, unsigned int n)
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{
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av_assert2(n > 0 && n <= 64);
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#ifdef BITSTREAM_READER_LE
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return bc->bits & (UINT64_MAX >> (64 - n));
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#else
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return bc->bits >> (64 - n);
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#endif
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}
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static inline void bits_priv_skip_remaining(BitstreamContext *bc, unsigned int n)
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{
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#ifdef BITSTREAM_READER_LE
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bc->bits >>= n;
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#else
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bc->bits <<= n;
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#endif
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bc->bits_valid -= n;
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}
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static inline uint64_t bits_priv_val_get(BitstreamContext *bc, unsigned int n)
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{
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uint64_t ret;
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av_assert2(n > 0 && n < 64);
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ret = bits_priv_val_show(bc, n);
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bits_priv_skip_remaining(bc, n);
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return ret;
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}
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/**
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* Return one bit from the buffer.
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*/
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static inline unsigned int bits_read_bit(BitstreamContext *bc)
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{
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if (!bc->bits_valid && bits_priv_refill_64(bc) < 0)
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return 0;
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return bits_priv_val_get(bc, 1);
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}
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/**
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* Return n bits from the buffer, n has to be in the 1-32 range.
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* May be faster than bits_read() when n is not a compile-time constant and is
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* known to be non-zero;
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*/
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static inline uint32_t bits_read_nz(BitstreamContext *bc, unsigned int n)
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{
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av_assert2(n > 0 && n <= 32);
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if (n > bc->bits_valid) {
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if (bits_priv_refill_32(bc) < 0)
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bc->bits_valid = n;
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}
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return bits_priv_val_get(bc, n);
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}
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/**
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* Return n bits from the buffer, n has to be in the 0-32 range.
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*/
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static inline uint32_t bits_read(BitstreamContext *bc, unsigned int n)
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{
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av_assert2(n <= 32);
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if (!n)
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return 0;
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return bits_read_nz(bc, n);
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}
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/**
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* Return n bits from the buffer, n has to be in the 0-63 range.
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*/
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static inline uint64_t bits_read_63(BitstreamContext *bc, unsigned int n)
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{
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uint64_t ret = 0;
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unsigned left = 0;
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av_assert2(n <= 63);
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if (!n)
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return 0;
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if (n > bc->bits_valid) {
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left = bc->bits_valid;
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n -= left;
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if (left)
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ret = bits_priv_val_get(bc, left);
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if (bits_priv_refill_64(bc) < 0)
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bc->bits_valid = n;
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}
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#ifdef BITSTREAM_READER_LE
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ret = bits_priv_val_get(bc, n) << left | ret;
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#else
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ret = bits_priv_val_get(bc, n) | ret << n;
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#endif
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return ret;
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}
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/**
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* Return n bits from the buffer, n has to be in the 0-64 range.
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*/
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static inline uint64_t bits_read_64(BitstreamContext *bc, unsigned int n)
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{
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av_assert2(n <= 64);
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if (n == 64) {
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uint64_t ret = bits_read_63(bc, 63);
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#ifdef BITSTREAM_READER_LE
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return ret | ((uint64_t)bits_read_bit(bc) << 63);
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#else
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return (ret << 1) | (uint64_t)bits_read_bit(bc);
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#endif
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}
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return bits_read_63(bc, n);
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}
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/**
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* Return n bits from the buffer as a signed integer.
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* n has to be in the 0-32 range.
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*/
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static inline int32_t bits_read_signed(BitstreamContext *bc, unsigned int n)
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{
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return sign_extend(bits_read(bc, n), n);
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}
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/**
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* Return n bits from the buffer but do not change the buffer state.
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* n has to be in the 1-32 range. May
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*/
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static inline uint32_t bits_peek_nz(BitstreamContext *bc, unsigned int n)
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{
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av_assert2(n > 0 && n <= 32);
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if (n > bc->bits_valid)
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bits_priv_refill_32(bc);
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return bits_priv_val_show(bc, n);
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}
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/**
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* Return n bits from the buffer but do not change the buffer state.
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* n has to be in the 0-32 range.
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*/
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static inline uint32_t bits_peek(BitstreamContext *bc, unsigned int n)
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{
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av_assert2(n <= 32);
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if (!n)
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return 0;
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return bits_peek_nz(bc, n);
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}
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/**
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* Return n bits from the buffer as a signed integer,
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* do not change the buffer state.
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* n has to be in the 0-32 range.
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*/
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static inline int bits_peek_signed(BitstreamContext *bc, unsigned int n)
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{
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return sign_extend(bits_peek(bc, n), n);
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}
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/**
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* Skip n bits in the buffer.
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*/
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static inline void bits_skip(BitstreamContext *bc, unsigned int n)
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{
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if (n < bc->bits_valid)
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bits_priv_skip_remaining(bc, n);
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else {
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n -= bc->bits_valid;
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bc->bits = 0;
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bc->bits_valid = 0;
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if (n >= 64) {
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unsigned int skip = n / 8;
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n -= skip * 8;
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bc->ptr += skip;
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}
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bits_priv_refill_64(bc);
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if (n)
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bits_priv_skip_remaining(bc, n);
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}
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}
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/**
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* Seek to the given bit position.
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*/
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static inline void bits_seek(BitstreamContext *bc, unsigned pos)
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{
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bc->ptr = bc->buffer;
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bc->bits = 0;
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bc->bits_valid = 0;
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bits_skip(bc, pos);
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}
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/**
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* Skip bits to a byte boundary.
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*/
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static inline const uint8_t *bits_align(BitstreamContext *bc)
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{
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unsigned int n = -bits_tell(bc) & 7;
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if (n)
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bits_skip(bc, n);
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return bc->buffer + (bits_tell(bc) >> 3);
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}
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/**
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* Read MPEG-1 dc-style VLC (sign bit + mantissa with no MSB).
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* If MSB not set it is negative.
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* @param n length in bits
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*/
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static inline int bits_read_xbits(BitstreamContext *bc, unsigned int n)
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{
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int32_t cache = bits_peek(bc, 32);
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int sign = ~cache >> 31;
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bits_priv_skip_remaining(bc, n);
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return ((((uint32_t)(sign ^ cache)) >> (32 - n)) ^ sign) - sign;
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}
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/**
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* Return decoded truncated unary code for the values 0, 1, 2.
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*/
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static inline int bits_decode012(BitstreamContext *bc)
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{
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if (!bits_read_bit(bc))
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return 0;
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else
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return bits_read_bit(bc) + 1;
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}
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/**
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* Return decoded truncated unary code for the values 2, 1, 0.
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*/
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static inline int bits_decode210(BitstreamContext *bc)
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{
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if (bits_read_bit(bc))
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return 0;
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else
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return 2 - bits_read_bit(bc);
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}
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/* Read sign bit and flip the sign of the provided value accordingly. */
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static inline int bits_apply_sign(BitstreamContext *bc, int val)
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{
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int sign = bits_read_signed(bc, 1);
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return (val ^ sign) - sign;
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}
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static inline int bits_skip_1stop_8data(BitstreamContext *s)
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{
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if (bits_left(s) <= 0)
|
||||
return AVERROR_INVALIDDATA;
|
||||
|
||||
while (bits_read_bit(s)) {
|
||||
bits_skip(s, 8);
|
||||
if (bits_left(s) <= 0)
|
||||
return AVERROR_INVALIDDATA;
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
/**
|
||||
* Return the LUT element for the given bitstream configuration.
|
||||
*/
|
||||
static inline int bits_priv_set_idx(BitstreamContext *bc, int code, int *n, int *nb_bits,
|
||||
const VLCElem *table)
|
||||
{
|
||||
unsigned idx;
|
||||
|
||||
*nb_bits = -*n;
|
||||
idx = bits_peek(bc, *nb_bits) + code;
|
||||
*n = table[idx].len;
|
||||
|
||||
return table[idx].sym;
|
||||
}
|
||||
|
||||
/**
|
||||
* Parse a vlc code.
|
||||
* @param bits is the number of bits which will be read at once, must be
|
||||
* identical to nb_bits in init_vlc()
|
||||
* @param max_depth is the number of times bits bits must be read to completely
|
||||
* read the longest vlc code
|
||||
* = (max_vlc_length + bits - 1) / bits
|
||||
* If the vlc code is invalid and max_depth=1, then no bits will be removed.
|
||||
* If the vlc code is invalid and max_depth>1, then the number of bits removed
|
||||
* is undefined.
|
||||
*/
|
||||
static inline int bits_read_vlc(BitstreamContext *bc, const VLCElem *table,
|
||||
int bits, int max_depth)
|
||||
{
|
||||
int nb_bits;
|
||||
unsigned idx = bits_peek(bc, bits);
|
||||
int code = table[idx].sym;
|
||||
int n = table[idx].len;
|
||||
|
||||
if (max_depth > 1 && n < 0) {
|
||||
bits_priv_skip_remaining(bc, bits);
|
||||
code = bits_priv_set_idx(bc, code, &n, &nb_bits, table);
|
||||
if (max_depth > 2 && n < 0) {
|
||||
bits_priv_skip_remaining(bc, nb_bits);
|
||||
code = bits_priv_set_idx(bc, code, &n, &nb_bits, table);
|
||||
}
|
||||
}
|
||||
bits_priv_skip_remaining(bc, n);
|
||||
|
||||
return code;
|
||||
}
|
||||
#undef BITS_DEFAULT_LE
|
||||
#undef BITS_DEFAULT_BE
|
||||
|
||||
#define BITS_RL_VLC(level, run, bc, table, bits, max_depth) \
|
||||
do { \
|
||||
@ -527,3 +161,32 @@ static inline int bits_read_vlc(BitstreamContext *bc, const VLCElem *table,
|
||||
} while (0)
|
||||
|
||||
#endif /* AVCODEC_BITSTREAM_H */
|
||||
|
||||
// the following is deliberately outside of the standard #include guards
|
||||
|
||||
#if defined(BITSTREAM_LE) && !defined(BITSTREAM_WANT_LE)
|
||||
# define BITSTREAM_WANT_LE
|
||||
#endif
|
||||
|
||||
#if defined(BITSTREAM_BE) && !defined(BITSTREAM_WANT_BE)
|
||||
# define BITSTREAM_WANT_BE
|
||||
#endif
|
||||
|
||||
#if defined(BITSTREAM_WANT_LE) && !defined(AVCODEC_BITSTREAM_LE)
|
||||
#define AVCODEC_BITSTREAM_LE
|
||||
|
||||
#define BITSTREAM_TEMPLATE_LE
|
||||
#include "bitstream_template.h"
|
||||
#undef BITSTREAM_TEMPLATE_LE
|
||||
|
||||
#endif
|
||||
|
||||
#if defined(BITSTREAM_WANT_BE) && !defined(AVCODEC_BITSTREAM_BE)
|
||||
#define AVCODEC_BITSTREAM_BE
|
||||
|
||||
#include "bitstream_template.h"
|
||||
|
||||
#endif
|
||||
|
||||
#undef BITSTREAM_WANT_LE
|
||||
#undef BITSTREAM_WANT_BE
|
||||
|
||||
496
libavcodec/bitstream_template.h
Normal file
496
libavcodec/bitstream_template.h
Normal file
@ -0,0 +1,496 @@
|
||||
/*
|
||||
* Copyright (c) 2016 Alexandra Hájková
|
||||
*
|
||||
* This file is part of FFmpeg.
|
||||
*
|
||||
* FFmpeg is free software; you can redistribute it and/or
|
||||
* modify it under the terms of the GNU Lesser General Public
|
||||
* License as published by the Free Software Foundation; either
|
||||
* version 2.1 of the License, or (at your option) any later version.
|
||||
*
|
||||
* FFmpeg is distributed in the hope that it will be useful,
|
||||
* but WITHOUT ANY WARRANTY; without even the implied warranty of
|
||||
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
|
||||
* Lesser General Public License for more details.
|
||||
*
|
||||
* You should have received a copy of the GNU Lesser General Public
|
||||
* License along with FFmpeg; if not, write to the Free Software
|
||||
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
|
||||
*/
|
||||
|
||||
#ifdef BITSTREAM_TEMPLATE_LE
|
||||
# define BS_SUFFIX_LOWER _le
|
||||
# define BS_SUFFIX_UPPER LE
|
||||
#else
|
||||
# define BS_SUFFIX_LOWER _be
|
||||
# define BS_SUFFIX_UPPER BE
|
||||
#endif
|
||||
|
||||
#define BS_JOIN(x, y, z) x ## y ## z
|
||||
#define BS_JOIN3(x, y, z) BS_JOIN(x, y, z)
|
||||
#define BS_FUNC(x) BS_JOIN3(bits_, x, BS_SUFFIX_LOWER)
|
||||
|
||||
#define BSCTX BS_JOIN3(Bitstream, Context, BS_SUFFIX_UPPER)
|
||||
|
||||
typedef struct BSCTX {
|
||||
uint64_t bits; // stores bits read from the buffer
|
||||
const uint8_t *buffer, *buffer_end;
|
||||
const uint8_t *ptr; // pointer to the position inside a buffer
|
||||
unsigned bits_valid; // number of bits left in bits field
|
||||
unsigned size_in_bits;
|
||||
} BSCTX;
|
||||
|
||||
/**
|
||||
* @return
|
||||
* - 0 on successful refill
|
||||
* - a negative number when bitstream end is hit
|
||||
*
|
||||
* Always succeeds when UNCHECKED_BITSTREAM_READER is enabled.
|
||||
*/
|
||||
static inline int BS_FUNC(priv_refill_64)(BSCTX *bc)
|
||||
{
|
||||
#if !UNCHECKED_BITSTREAM_READER
|
||||
if (bc->ptr >= bc->buffer_end)
|
||||
return -1;
|
||||
#endif
|
||||
|
||||
#ifdef BITSTREAM_TEMPLATE_LE
|
||||
bc->bits = AV_RL64(bc->ptr);
|
||||
#else
|
||||
bc->bits = AV_RB64(bc->ptr);
|
||||
#endif
|
||||
bc->ptr += 8;
|
||||
bc->bits_valid = 64;
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
/**
|
||||
* @return
|
||||
* - 0 on successful refill
|
||||
* - a negative number when bitstream end is hit
|
||||
*
|
||||
* Always succeeds when UNCHECKED_BITSTREAM_READER is enabled.
|
||||
*/
|
||||
static inline int BS_FUNC(priv_refill_32)(BSCTX *bc)
|
||||
{
|
||||
#if !UNCHECKED_BITSTREAM_READER
|
||||
if (bc->ptr >= bc->buffer_end)
|
||||
return -1;
|
||||
#endif
|
||||
|
||||
#ifdef BITSTREAM_TEMPLATE_LE
|
||||
bc->bits |= (uint64_t)AV_RL32(bc->ptr) << bc->bits_valid;
|
||||
#else
|
||||
bc->bits |= (uint64_t)AV_RB32(bc->ptr) << (32 - bc->bits_valid);
|
||||
#endif
|
||||
bc->ptr += 4;
|
||||
bc->bits_valid += 32;
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
/**
|
||||
* Initialize BitstreamContext.
|
||||
* @param buffer bitstream buffer, must be AV_INPUT_BUFFER_PADDING_SIZE bytes
|
||||
* larger than the actual read bits because some optimized bitstream
|
||||
* readers read 32 or 64 bits at once and could read over the end
|
||||
* @param bit_size the size of the buffer in bits
|
||||
* @return 0 on success, AVERROR_INVALIDDATA if the buffer_size would overflow.
|
||||
*/
|
||||
static inline int BS_FUNC(init)(BSCTX *bc, const uint8_t *buffer,
|
||||
unsigned int bit_size)
|
||||
{
|
||||
unsigned int buffer_size;
|
||||
|
||||
if (bit_size > INT_MAX - 7 || !buffer) {
|
||||
bc->buffer = NULL;
|
||||
bc->ptr = NULL;
|
||||
bc->bits_valid = 0;
|
||||
return AVERROR_INVALIDDATA;
|
||||
}
|
||||
|
||||
buffer_size = (bit_size + 7) >> 3;
|
||||
|
||||
bc->buffer = buffer;
|
||||
bc->buffer_end = buffer + buffer_size;
|
||||
bc->ptr = bc->buffer;
|
||||
bc->size_in_bits = bit_size;
|
||||
bc->bits_valid = 0;
|
||||
bc->bits = 0;
|
||||
|
||||
BS_FUNC(priv_refill_64)(bc);
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
/**
|
||||
* Initialize BitstreamContext.
|
||||
* @param buffer bitstream buffer, must be AV_INPUT_BUFFER_PADDING_SIZE bytes
|
||||
* larger than the actual read bits because some optimized bitstream
|
||||
* readers read 32 or 64 bits at once and could read over the end
|
||||
* @param byte_size the size of the buffer in bytes
|
||||
* @return 0 on success, AVERROR_INVALIDDATA if the buffer_size would overflow
|
||||
*/
|
||||
static inline int BS_FUNC(init8)(BSCTX *bc, const uint8_t *buffer,
|
||||
unsigned int byte_size)
|
||||
{
|
||||
if (byte_size > INT_MAX / 8)
|
||||
return AVERROR_INVALIDDATA;
|
||||
return BS_FUNC(init)(bc, buffer, byte_size * 8);
|
||||
}
|
||||
|
||||
/**
|
||||
* Return number of bits already read.
|
||||
*/
|
||||
static inline int BS_FUNC(tell)(const BSCTX *bc)
|
||||
{
|
||||
return (bc->ptr - bc->buffer) * 8 - bc->bits_valid;
|
||||
}
|
||||
|
||||
/**
|
||||
* Return buffer size in bits.
|
||||
*/
|
||||
static inline int BS_FUNC(size)(const BSCTX *bc)
|
||||
{
|
||||
return bc->size_in_bits;
|
||||
}
|
||||
|
||||
/**
|
||||
* Return the number of the bits left in a buffer.
|
||||
*/
|
||||
static inline int BS_FUNC(left)(const BSCTX *bc)
|
||||
{
|
||||
return (bc->buffer - bc->ptr) * 8 + bc->size_in_bits + bc->bits_valid;
|
||||
}
|
||||
|
||||
static inline uint64_t BS_FUNC(priv_val_show)(BSCTX *bc, unsigned int n)
|
||||
{
|
||||
av_assert2(n > 0 && n <= 64);
|
||||
|
||||
#ifdef BITSTREAM_TEMPLATE_LE
|
||||
return bc->bits & (UINT64_MAX >> (64 - n));
|
||||
#else
|
||||
return bc->bits >> (64 - n);
|
||||
#endif
|
||||
}
|
||||
|
||||
static inline void BS_FUNC(priv_skip_remaining)(BSCTX *bc, unsigned int n)
|
||||
{
|
||||
#ifdef BITSTREAM_TEMPLATE_LE
|
||||
bc->bits >>= n;
|
||||
#else
|
||||
bc->bits <<= n;
|
||||
#endif
|
||||
bc->bits_valid -= n;
|
||||
}
|
||||
|
||||
static inline uint64_t BS_FUNC(priv_val_get)(BSCTX *bc, unsigned int n)
|
||||
{
|
||||
uint64_t ret;
|
||||
|
||||
av_assert2(n > 0 && n < 64);
|
||||
|
||||
ret = BS_FUNC(priv_val_show)(bc, n);
|
||||
BS_FUNC(priv_skip_remaining)(bc, n);
|
||||
|
||||
return ret;
|
||||
}
|
||||
|
||||
/**
|
||||
* Return one bit from the buffer.
|
||||
*/
|
||||
static inline unsigned int BS_FUNC(read_bit)(BSCTX *bc)
|
||||
{
|
||||
if (!bc->bits_valid && BS_FUNC(priv_refill_64)(bc) < 0)
|
||||
return 0;
|
||||
|
||||
return BS_FUNC(priv_val_get)(bc, 1);
|
||||
}
|
||||
|
||||
/**
|
||||
* Return n bits from the buffer, n has to be in the 1-32 range.
|
||||
* May be faster than bits_read() when n is not a compile-time constant and is
|
||||
* known to be non-zero;
|
||||
*/
|
||||
static inline uint32_t BS_FUNC(read_nz)(BSCTX *bc, unsigned int n)
|
||||
{
|
||||
av_assert2(n > 0 && n <= 32);
|
||||
|
||||
if (n > bc->bits_valid) {
|
||||
if (BS_FUNC(priv_refill_32)(bc) < 0)
|
||||
bc->bits_valid = n;
|
||||
}
|
||||
|
||||
return BS_FUNC(priv_val_get)(bc, n);
|
||||
}
|
||||
|
||||
/**
|
||||
* Return n bits from the buffer, n has to be in the 0-32 range.
|
||||
*/
|
||||
static inline uint32_t BS_FUNC(read)(BSCTX *bc, unsigned int n)
|
||||
{
|
||||
av_assert2(n <= 32);
|
||||
|
||||
if (!n)
|
||||
return 0;
|
||||
|
||||
return BS_FUNC(read_nz)(bc, n);
|
||||
}
|
||||
|
||||
/**
|
||||
* Return n bits from the buffer, n has to be in the 0-63 range.
|
||||
*/
|
||||
static inline uint64_t BS_FUNC(read_63)(BSCTX *bc, unsigned int n)
|
||||
{
|
||||
uint64_t ret = 0;
|
||||
unsigned left = 0;
|
||||
|
||||
av_assert2(n <= 63);
|
||||
|
||||
if (!n)
|
||||
return 0;
|
||||
|
||||
if (n > bc->bits_valid) {
|
||||
left = bc->bits_valid;
|
||||
n -= left;
|
||||
|
||||
if (left)
|
||||
ret = BS_FUNC(priv_val_get)(bc, left);
|
||||
|
||||
if (BS_FUNC(priv_refill_64)(bc) < 0)
|
||||
bc->bits_valid = n;
|
||||
|
||||
}
|
||||
|
||||
#ifdef BITSTREAM_TEMPLATE_LE
|
||||
ret = BS_FUNC(priv_val_get)(bc, n) << left | ret;
|
||||
#else
|
||||
ret = BS_FUNC(priv_val_get)(bc, n) | ret << n;
|
||||
#endif
|
||||
|
||||
return ret;
|
||||
}
|
||||
|
||||
/**
|
||||
* Return n bits from the buffer, n has to be in the 0-64 range.
|
||||
*/
|
||||
static inline uint64_t BS_FUNC(read_64)(BSCTX *bc, unsigned int n)
|
||||
{
|
||||
av_assert2(n <= 64);
|
||||
|
||||
if (n == 64) {
|
||||
uint64_t ret = BS_FUNC(read_63)(bc, 63);
|
||||
#ifdef BITSTREAM_TEMPLATE_LE
|
||||
return ret | ((uint64_t)BS_FUNC(read_bit)(bc) << 63);
|
||||
#else
|
||||
return (ret << 1) | (uint64_t)BS_FUNC(read_bit)(bc);
|
||||
#endif
|
||||
}
|
||||
return BS_FUNC(read_63)(bc, n);
|
||||
}
|
||||
|
||||
/**
|
||||
* Return n bits from the buffer as a signed integer.
|
||||
* n has to be in the 0-32 range.
|
||||
*/
|
||||
static inline int32_t BS_FUNC(read_signed)(BSCTX *bc, unsigned int n)
|
||||
{
|
||||
return sign_extend(BS_FUNC(read)(bc, n), n);
|
||||
}
|
||||
|
||||
/**
|
||||
* Return n bits from the buffer but do not change the buffer state.
|
||||
* n has to be in the 1-32 range. May
|
||||
*/
|
||||
static inline uint32_t BS_FUNC(peek_nz)(BSCTX *bc, unsigned int n)
|
||||
{
|
||||
av_assert2(n > 0 && n <= 32);
|
||||
|
||||
if (n > bc->bits_valid)
|
||||
BS_FUNC(priv_refill_32)(bc);
|
||||
|
||||
return BS_FUNC(priv_val_show)(bc, n);
|
||||
}
|
||||
|
||||
/**
|
||||
* Return n bits from the buffer but do not change the buffer state.
|
||||
* n has to be in the 0-32 range.
|
||||
*/
|
||||
static inline uint32_t BS_FUNC(peek)(BSCTX *bc, unsigned int n)
|
||||
{
|
||||
av_assert2(n <= 32);
|
||||
|
||||
if (!n)
|
||||
return 0;
|
||||
|
||||
return BS_FUNC(peek_nz)(bc, n);
|
||||
}
|
||||
|
||||
/**
|
||||
* Return n bits from the buffer as a signed integer,
|
||||
* do not change the buffer state.
|
||||
* n has to be in the 0-32 range.
|
||||
*/
|
||||
static inline int BS_FUNC(peek_signed)(BSCTX *bc, unsigned int n)
|
||||
{
|
||||
return sign_extend(BS_FUNC(peek)(bc, n), n);
|
||||
}
|
||||
|
||||
/**
|
||||
* Skip n bits in the buffer.
|
||||
*/
|
||||
static inline void BS_FUNC(skip)(BSCTX *bc, unsigned int n)
|
||||
{
|
||||
if (n < bc->bits_valid)
|
||||
BS_FUNC(priv_skip_remaining)(bc, n);
|
||||
else {
|
||||
n -= bc->bits_valid;
|
||||
bc->bits = 0;
|
||||
bc->bits_valid = 0;
|
||||
|
||||
if (n >= 64) {
|
||||
unsigned int skip = n / 8;
|
||||
|
||||
n -= skip * 8;
|
||||
bc->ptr += skip;
|
||||
}
|
||||
BS_FUNC(priv_refill_64)(bc);
|
||||
if (n)
|
||||
BS_FUNC(priv_skip_remaining)(bc, n);
|
||||
}
|
||||
}
|
||||
|
||||
/**
|
||||
* Seek to the given bit position.
|
||||
*/
|
||||
static inline void BS_FUNC(seek)(BSCTX *bc, unsigned pos)
|
||||
{
|
||||
bc->ptr = bc->buffer;
|
||||
bc->bits = 0;
|
||||
bc->bits_valid = 0;
|
||||
|
||||
BS_FUNC(skip)(bc, pos);
|
||||
}
|
||||
|
||||
/**
|
||||
* Skip bits to a byte boundary.
|
||||
*/
|
||||
static inline const uint8_t *BS_FUNC(align)(BSCTX *bc)
|
||||
{
|
||||
unsigned int n = -BS_FUNC(tell)(bc) & 7;
|
||||
if (n)
|
||||
BS_FUNC(skip)(bc, n);
|
||||
return bc->buffer + (BS_FUNC(tell)(bc) >> 3);
|
||||
}
|
||||
|
||||
/**
|
||||
* Read MPEG-1 dc-style VLC (sign bit + mantissa with no MSB).
|
||||
* If MSB not set it is negative.
|
||||
* @param n length in bits
|
||||
*/
|
||||
static inline int BS_FUNC(read_xbits)(BSCTX *bc, unsigned int n)
|
||||
{
|
||||
int32_t cache = BS_FUNC(peek)(bc, 32);
|
||||
int sign = ~cache >> 31;
|
||||
BS_FUNC(priv_skip_remaining)(bc, n);
|
||||
|
||||
return ((((uint32_t)(sign ^ cache)) >> (32 - n)) ^ sign) - sign;
|
||||
}
|
||||
|
||||
/**
|
||||
* Return decoded truncated unary code for the values 0, 1, 2.
|
||||
*/
|
||||
static inline int BS_FUNC(decode012)(BSCTX *bc)
|
||||
{
|
||||
if (!BS_FUNC(read_bit)(bc))
|
||||
return 0;
|
||||
else
|
||||
return BS_FUNC(read_bit)(bc) + 1;
|
||||
}
|
||||
|
||||
/**
|
||||
* Return decoded truncated unary code for the values 2, 1, 0.
|
||||
*/
|
||||
static inline int BS_FUNC(decode210)(BSCTX *bc)
|
||||
{
|
||||
if (BS_FUNC(read_bit)(bc))
|
||||
return 0;
|
||||
else
|
||||
return 2 - BS_FUNC(read_bit)(bc);
|
||||
}
|
||||
|
||||
/* Read sign bit and flip the sign of the provided value accordingly. */
|
||||
static inline int BS_FUNC(apply_sign)(BSCTX *bc, int val)
|
||||
{
|
||||
int sign = BS_FUNC(read_signed)(bc, 1);
|
||||
return (val ^ sign) - sign;
|
||||
}
|
||||
|
||||
static inline int BS_FUNC(skip_1stop_8data)(BSCTX *s)
|
||||
{
|
||||
if (BS_FUNC(left)(s) <= 0)
|
||||
return AVERROR_INVALIDDATA;
|
||||
|
||||
while (BS_FUNC(read_bit)(s)) {
|
||||
BS_FUNC(skip)(s, 8);
|
||||
if (BS_FUNC(left)(s) <= 0)
|
||||
return AVERROR_INVALIDDATA;
|
||||
}
|
||||
|
||||
return 0;
|
||||
}
|
||||
|
||||
/**
|
||||
* Return the LUT element for the given bitstream configuration.
|
||||
*/
|
||||
static inline int BS_FUNC(priv_set_idx)(BSCTX *bc, int code, int *n,
|
||||
int *nb_bits, const VLCElem *table)
|
||||
{
|
||||
unsigned idx;
|
||||
|
||||
*nb_bits = -*n;
|
||||
idx = BS_FUNC(peek)(bc, *nb_bits) + code;
|
||||
*n = table[idx].len;
|
||||
|
||||
return table[idx].sym;
|
||||
}
|
||||
|
||||
/**
|
||||
* Parse a vlc code.
|
||||
* @param bits is the number of bits which will be read at once, must be
|
||||
* identical to nb_bits in init_vlc()
|
||||
* @param max_depth is the number of times bits bits must be read to completely
|
||||
* read the longest vlc code
|
||||
* = (max_vlc_length + bits - 1) / bits
|
||||
* If the vlc code is invalid and max_depth=1, then no bits will be removed.
|
||||
* If the vlc code is invalid and max_depth>1, then the number of bits removed
|
||||
* is undefined.
|
||||
*/
|
||||
static inline int BS_FUNC(read_vlc)(BSCTX *bc, const VLCElem *table,
|
||||
int bits, int max_depth)
|
||||
{
|
||||
int nb_bits;
|
||||
unsigned idx = BS_FUNC(peek)(bc, bits);
|
||||
int code = table[idx].sym;
|
||||
int n = table[idx].len;
|
||||
|
||||
if (max_depth > 1 && n < 0) {
|
||||
BS_FUNC(priv_skip_remaining)(bc, bits);
|
||||
code = BS_FUNC(priv_set_idx)(bc, code, &n, &nb_bits, table);
|
||||
if (max_depth > 2 && n < 0) {
|
||||
BS_FUNC(priv_skip_remaining)(bc, nb_bits);
|
||||
code = BS_FUNC(priv_set_idx)(bc, code, &n, &nb_bits, table);
|
||||
}
|
||||
}
|
||||
BS_FUNC(priv_skip_remaining)(bc, n);
|
||||
|
||||
return code;
|
||||
}
|
||||
|
||||
#undef BSCTX
|
||||
#undef BS_FUNC
|
||||
#undef BS_JOIN3
|
||||
#undef BS_JOIN
|
||||
#undef BS_SUFFIX_UPPER
|
||||
#undef BS_SUFFIX_LOWER
|
||||
@ -21,6 +21,7 @@ Headers without standard inclusion guards:
|
||||
compat/djgpp/math.h
|
||||
compat/float/float.h
|
||||
compat/float/limits.h
|
||||
libavcodec/bitstream_template.h
|
||||
tools/decode_simple.h
|
||||
Use of av_clip() where av_clip_uintp2() could be used:
|
||||
Use of av_clip() where av_clip_intp2() could be used:
|
||||
|
||||
Loading…
Reference in New Issue
Block a user