149 lines
4.5 KiB
C
149 lines
4.5 KiB
C
/*
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* Bytestream functions
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* copyright (c) 2006 Baptiste Coudurier <baptiste.coudurier@free.fr>
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*
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* This file is part of Libav.
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*
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* Libav is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation; either
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* version 2.1 of the License, or (at your option) any later version.
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*
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* Libav is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with Libav; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#ifndef AVCODEC_BYTESTREAM_H
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#define AVCODEC_BYTESTREAM_H
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#include <string.h>
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#include "libavutil/common.h"
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#include "libavutil/intreadwrite.h"
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typedef struct {
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const uint8_t *buffer, *buffer_end, *buffer_start;
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} GetByteContext;
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#define DEF_T(type, name, bytes, read, write) \
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static av_always_inline type bytestream_get_ ## name(const uint8_t **b){\
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(*b) += bytes;\
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return read(*b - bytes);\
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}\
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static av_always_inline void bytestream_put_ ##name(uint8_t **b, const type value){\
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write(*b, value);\
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(*b) += bytes;\
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}\
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static av_always_inline type bytestream2_get_ ## name ## u(GetByteContext *g)\
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{\
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return bytestream_get_ ## name(&g->buffer);\
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}\
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static av_always_inline type bytestream2_get_ ## name(GetByteContext *g)\
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{\
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if (g->buffer_end - g->buffer < bytes)\
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return 0;\
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return bytestream2_get_ ## name ## u(g);\
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}\
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static av_always_inline type bytestream2_peek_ ## name(GetByteContext *g)\
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{\
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if (g->buffer_end - g->buffer < bytes)\
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return 0;\
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return read(g->buffer);\
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}
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#define DEF(name, bytes, read, write) \
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DEF_T(unsigned int, name, bytes, read, write)
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#define DEF64(name, bytes, read, write) \
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DEF_T(uint64_t, name, bytes, read, write)
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DEF64(le64, 8, AV_RL64, AV_WL64)
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DEF (le32, 4, AV_RL32, AV_WL32)
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DEF (le24, 3, AV_RL24, AV_WL24)
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DEF (le16, 2, AV_RL16, AV_WL16)
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DEF64(be64, 8, AV_RB64, AV_WB64)
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DEF (be32, 4, AV_RB32, AV_WB32)
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DEF (be24, 3, AV_RB24, AV_WB24)
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DEF (be16, 2, AV_RB16, AV_WB16)
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DEF (byte, 1, AV_RB8 , AV_WB8 )
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#undef DEF
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#undef DEF64
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#undef DEF_T
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static av_always_inline void bytestream2_init(GetByteContext *g,
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const uint8_t *buf, int buf_size)
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{
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g->buffer = buf;
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g->buffer_start = buf;
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g->buffer_end = buf + buf_size;
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}
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static av_always_inline unsigned int bytestream2_get_bytes_left(GetByteContext *g)
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{
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return g->buffer_end - g->buffer;
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}
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static av_always_inline void bytestream2_skip(GetByteContext *g,
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unsigned int size)
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{
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g->buffer += FFMIN(g->buffer_end - g->buffer, size);
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}
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static av_always_inline int bytestream2_tell(GetByteContext *g)
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{
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return (int)(g->buffer - g->buffer_start);
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}
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static av_always_inline int bytestream2_seek(GetByteContext *g, int offset,
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int whence)
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{
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switch (whence) {
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case SEEK_CUR:
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offset = av_clip(offset, -(g->buffer - g->buffer_start),
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g->buffer_end - g->buffer);
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g->buffer += offset;
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break;
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case SEEK_END:
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offset = av_clip(offset, -(g->buffer_end - g->buffer_start), 0);
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g->buffer = g->buffer_end + offset;
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break;
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case SEEK_SET:
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offset = av_clip(offset, 0, g->buffer_end - g->buffer_start);
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g->buffer = g->buffer_start + offset;
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break;
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default:
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return AVERROR(EINVAL);
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}
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return bytestream2_tell(g);
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}
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static av_always_inline unsigned int bytestream2_get_buffer(GetByteContext *g,
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uint8_t *dst,
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unsigned int size)
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{
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int size2 = FFMIN(g->buffer_end - g->buffer, size);
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memcpy(dst, g->buffer, size2);
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g->buffer += size2;
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return size2;
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}
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static av_always_inline unsigned int bytestream_get_buffer(const uint8_t **b, uint8_t *dst, unsigned int size)
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{
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memcpy(dst, *b, size);
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(*b) += size;
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return size;
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}
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static av_always_inline void bytestream_put_buffer(uint8_t **b, const uint8_t *src, unsigned int size)
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{
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memcpy(*b, src, size);
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(*b) += size;
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}
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#endif /* AVCODEC_BYTESTREAM_H */
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