rockbox/utils/rbutilqt/mspack/qtm.h
Dominik Riebeling c876d3bbef rbutil: Merge rbutil with utils folder.
rbutil uses several components from the utils folder, and can be
considered part of utils too. Having it in a separate folder is an
arbitrary split that doesn't help anymore these days, so merge them.

This also allows other utils to easily use libtools.make without the
need to navigate to a different folder.

Change-Id: I3fc2f4de19e3e776553efb5dea5f779dfec0dc21
2021-12-24 18:05:53 +01:00

128 lines
4.4 KiB
C

/* This file is part of libmspack.
* (C) 2003-2004 Stuart Caie.
*
* The Quantum method was created by David Stafford, adapted by Microsoft
* Corporation.
*
* libmspack is free software; you can redistribute it and/or modify it under
* the terms of the GNU Lesser General Public License (LGPL) version 2.1
*
* For further details, see the file COPYING.LIB distributed with libmspack
*/
#ifndef MSPACK_QTM_H
#define MSPACK_QTM_H 1
#ifdef __cplusplus
extern "C" {
#endif
/* Quantum compression / decompression definitions */
#define QTM_FRAME_SIZE (32768)
struct qtmd_modelsym {
unsigned short sym, cumfreq;
};
struct qtmd_model {
int shiftsleft, entries;
struct qtmd_modelsym *syms;
};
struct qtmd_stream {
struct mspack_system *sys; /* I/O routines */
struct mspack_file *input; /* input file handle */
struct mspack_file *output; /* output file handle */
unsigned char *window; /* decoding window */
unsigned int window_size; /* window size */
unsigned int window_posn; /* decompression offset within window */
unsigned int frame_todo; /* bytes remaining for current frame */
unsigned short H, L, C; /* high/low/current: arith coding state */
unsigned char header_read; /* have we started decoding a new frame? */
int error;
/* I/O buffers */
unsigned char *inbuf, *i_ptr, *i_end, *o_ptr, *o_end;
unsigned int bit_buffer, inbuf_size;
unsigned char bits_left, input_end;
/* four literal models, each representing 64 symbols
* model0 for literals from 0 to 63 (selector = 0)
* model1 for literals from 64 to 127 (selector = 1)
* model2 for literals from 128 to 191 (selector = 2)
* model3 for literals from 129 to 255 (selector = 3) */
struct qtmd_model model0, model1, model2, model3;
/* three match models.
* model4 for match with fixed length of 3 bytes
* model5 for match with fixed length of 4 bytes
* model6 for variable length match, encoded with model6len model */
struct qtmd_model model4, model5, model6, model6len;
/* selector model. 0-6 to say literal (0,1,2,3) or match (4,5,6) */
struct qtmd_model model7;
/* symbol arrays for all models */
struct qtmd_modelsym m0sym[64 + 1];
struct qtmd_modelsym m1sym[64 + 1];
struct qtmd_modelsym m2sym[64 + 1];
struct qtmd_modelsym m3sym[64 + 1];
struct qtmd_modelsym m4sym[24 + 1];
struct qtmd_modelsym m5sym[36 + 1];
struct qtmd_modelsym m6sym[42 + 1], m6lsym[27 + 1];
struct qtmd_modelsym m7sym[7 + 1];
};
/* allocates Quantum decompression state for decoding the given stream.
*
* - returns NULL if window_bits is outwith the range 10 to 21 (inclusive).
*
* - uses system->alloc() to allocate memory
*
* - returns NULL if not enough memory
*
* - window_bits is the size of the Quantum window, from 1Kb (10) to 2Mb (21).
*
* - input_buffer_size is the number of bytes to use to store bitstream data.
*/
extern struct qtmd_stream *qtmd_init(struct mspack_system *system,
struct mspack_file *input,
struct mspack_file *output,
int window_bits,
int input_buffer_size);
/* decompresses, or decompresses more of, a Quantum stream.
*
* - out_bytes of data will be decompressed and the function will return
* with an MSPACK_ERR_OK return code.
*
* - decompressing will stop as soon as out_bytes is reached. if the true
* amount of bytes decoded spills over that amount, they will be kept for
* a later invocation of qtmd_decompress().
*
* - the output bytes will be passed to the system->write() function given in
* qtmd_init(), using the output file handle given in qtmd_init(). More
* than one call may be made to system->write()
*
* - Quantum will read input bytes as necessary using the system->read()
* function given in qtmd_init(), using the input file handle given in
* qtmd_init(). This will continue until system->read() returns 0 bytes,
* or an error.
*/
extern int qtmd_decompress(struct qtmd_stream *qtm, off_t out_bytes);
/* frees all state associated with a Quantum data stream
*
* - calls system->free() using the system pointer given in qtmd_init()
*/
void qtmd_free(struct qtmd_stream *qtm);
#ifdef __cplusplus
}
#endif
#endif