GPMF_bitstream.h

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// SPDX-License-Identifier: MIT
// SPDX-FileCopyrightText: Copyright 2017 GoPro Inc (http://gopro.com/).
 
#ifndef _GPMF_BITSTREAM_H
#define _GPMF_BITSTREAM_H
 
#ifdef __cplusplus
extern "C" {
#endif
 
#include <stdint.h>
 
typedef struct rlv {    // Codebook entries for arbitrary runs
        uint16_t size;          // Size of code word in bits
        uint16_t bits;          // Code word bits right justified
        uint16_t count;         // Run length for zeros
        int16_t  value;         // Value for difference
} RLV;
 
typedef const struct {
        int length;                     // Number of entries in the code book
        RLV entries[39];
} RLVTABLE;
 
#define BITSTREAM_WORD_TYPE                     uint16_t                // use 16-bit buffer for compression
#define BITSTREAM_WORD_SIZE                     16                              // use 16-bit buffer for compression
#define BITSTREAM_ERROR_OVERFLOW        1
 
#define BITMASK(n)              _bitmask[n]
#define _BITMASK(n)             ((((BITSTREAM_WORD_TYPE )1 << (n))) - 1)
 
static const BITSTREAM_WORD_TYPE  _bitmask[] =
{
        _BITMASK(0),  _BITMASK(1),  _BITMASK(2),  _BITMASK(3),
        _BITMASK(4),  _BITMASK(5),  _BITMASK(6),  _BITMASK(7),
        _BITMASK(8),  _BITMASK(9),  _BITMASK(10), _BITMASK(11),
        _BITMASK(12), _BITMASK(13), _BITMASK(14), _BITMASK(15),
        0xFFFF
};
 
 
 
typedef struct bitstream
{
        int32_t error;                          // Error parsing the bitstream
        int32_t bitsFree;                       // Number of bits available in the current word
        uint8_t *lpCurrentWord;         // Pointer to next word in block
        int32_t wordsUsed;                      // Number of words used in the block
        int32_t dwBlockLength;          // Number of entries in the block
        uint16_t wBuffer;                       // Current word bit buffer
        uint16_t bits_per_src_word;     // Bitused in the source word. e.g. 's' = 16-bits
} BITSTREAM;
 
 
static RLVTABLE enchuftable = {
        39,
        {
          { 1, 0b0,   1,  0 },  // m0
          { 2, 0b10,   1,  1 }, // m1
          { 4, 0b1100,   1,  2 },       // m2
          { 5, 0b11011,   1,  3 },      // m3
          { 5, 0b11101,   1,  4 },      // m4
          { 6, 0b110100,   1,  5 },     // m5
          { 6, 0b110101,   1,  6 },     // m6
          { 6, 0b111110,   1,  7 },     // m7
          { 7, 0b1110000,   1,  8 },    // m8
          { 7, 0b1110011,   1,  9 },    // m9
          { 7, 0b1111000,   1, 10 },    // m10
          { 7, 0b1111001,   1, 11 },    // m11
          { 7, 0b1111011,   1, 12 },    // m12
          { 8, 0b11100100,   1, 13 },   // m13
          { 8, 0b11100101,   1, 14 },   // m14
          { 8, 0b11110100,   1, 15 },   // m15
          { 9, 0b111000101,   1, 16 },  // m16
          { 9, 0b111000110,   1, 17 },  // m17
          { 9, 0b111101010,   1, 18 },  // m18
          { 10, 0b1110001000,   1, 19 },        // m19
          { 10, 0b1110001110,   1, 20 },        // m20
          { 10, 0b1111010110,   1, 21 },        // m21
          { 10, 0b1111111100,   1, 22 },        // m22
          { 11, 0b11100010010,   1, 23 },       // m23
          { 11, 0b11100011111,   1, 24 },       // m24
          { 11, 0b11110101110,   1, 25 },       // m25
          { 12, 0b111000100111,   1, 26 },      // m26
          { 12, 0b111000111101,   1, 27 },      // m27
          { 12, 0b111101011111,   1, 28 },      // m28
          { 13, 0b1110001001101,   1, 29 },     // m29
          { 13, 0b1110001111001,   1, 30 },     // m30
          { 13, 0b1111010111101,   1, 31 },     // m31
          { 14, 0b11100010011000,   1, 32 },    // m32
          { 14, 0b11100011110000,   1, 33 },    // m33
          { 14, 0b11110101111000,   1, 34 },    // m34
          { 14, 0b11110101111001,   1, 35 },    // m35
          { 15, 0b111000100110010,   1, 36 },   // m36
          { 15, 0b111000100110011,   1, 37 },   // m37
          { 15, 0b111000111100011,   1, 38 },   // m38
        }                 
};                        
 
 
 
static RLVTABLE enczerorunstable = {
        4,
        {
                { 7, 0b1111110,  16,  0 },              // z16
                { 8, 0b11111110,  32,  0 },             // z32
                { 9, 0b111111111,  64,  0 },    // z64
                { 10,0b1111111101, 128,  0 },   // z128
        }
};      
 
#define HUFF_ESC_CODE_ENTRY             0       
#define HUFF_END_CODE_ENTRY             1       
static RLVTABLE enccontrolcodestable = {
        2,
        {
                { 16, 0b1110001111000100, 0, 0 },       // escape code for direct data <ESC><data>Continue
                { 16, 0b1110001111000101, 0, 0 },       // end code.  Ends each compressed stream
        }
};
 
 
 
#ifdef __cplusplus
}
#endif
 
#endif