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73 lines
2.5 KiB
C
73 lines
2.5 KiB
C
/*
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* Arithmetic coder
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*
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* Copyright (c) 2018-2019 Fabrice Bellard
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*
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* Permission is hereby granted, free of charge, to any person obtaining a copy
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* of this software and associated documentation files (the "Software"), to deal
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* in the Software without restriction, including without limitation the rights
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* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
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* copies of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be included in
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* all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
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* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
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* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
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* THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
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* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
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* THE SOFTWARE.
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*/
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#ifndef ARITH_H
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#define ARITH_H
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#define PROB_UNIT_BITS 15
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#define PROB_UNIT (1 << PROB_UNIT_BITS)
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typedef void PutBitWriteFunc(void *opaque, const uint8_t *buf, size_t buf_size);
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typedef struct {
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uint32_t range;
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uint32_t low;
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uint8_t current_byte;
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uint32_t n_bytes;
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uint8_t *buf;
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size_t buf_size;
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size_t idx; /* current position in bytes */
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PutBitWriteFunc *write_func;
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void *opaque;
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uint64_t byte_count;
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} PutBitState;
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void put_bit_init(PutBitState *s, uint8_t *buf, int buf_size,
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PutBitWriteFunc *write_func, void *opaque);
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void put_bit(PutBitState *s, int prob0, int bit);
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void put_bit_raw(PutBitState *s, int bit);
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int64_t put_bit_flush(PutBitState *s);
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int64_t put_bit_get_bit_count(PutBitState *s);
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/* return the number of read bytes */
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typedef ssize_t GetBitReadFunc(void *opaque, uint8_t *buf, size_t buf_size);
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typedef struct {
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uint8_t *buf;
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int buf_len;
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int buf_size;
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int idx;
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uint32_t low;
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uint32_t range;
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GetBitReadFunc *read_func;
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void *opaque;
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uint64_t byte_count;
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} GetBitState;
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void get_bit_init(GetBitState *s, uint8_t *buf, size_t buf_size,
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GetBitReadFunc *read_func, void *opaque);
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int get_bit(GetBitState *s, int prob0);
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int get_bit_raw(GetBitState *s);
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int64_t get_bit_get_bit_count(GetBitState *s);
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#endif /* ARITH_H */
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