/*
 * ArithmeticDecoder.h
 *
 * Copyright (c) 2017-present, MacPaw Inc. All rights reserved.
 *
 * This library 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.
 *
 * This library 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 this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston,
 * MA 02110-1301  USA
 */
#ifndef __WINZIP_JPEG_ARITHMETIC_DECODER_H__
#define __WINZIP_JPEG_ARITHMETIC_DECODER_H__

#include "InputStream.h"

#include <stdbool.h>
#include <stdint.h>

typedef struct WinZipJPEGArithmeticDecoder
{
    WinZipJPEGReadFunction *readfunc;
    void                   *inputcontext;

    bool eof;

    uint8_t currbyte, lastbyte;

    uint8_t  kmin2;  // LPS count for reduction of Q by 4
    uint8_t  kmin1;  // LPS count for reduction of Q by 2
    uint8_t  kmin;   // largest LSP[sic] count for smaller Q
    // uint8_t kavg; // expected average LPS count
    uint8_t  kmax;  // smallest LPS count for larger Q
    uint32_t x;     // finite pricesion window on code stream
    int32_t  lp;    // minus log p --- used only for testing
    int32_t  lr;    // minus log of the range
    int32_t  lrm;   // maximum lr before change index
    int32_t  lx;    // decoder - log x
    uint32_t dx;    // antilog of lr -- used only for testing
} WinZipJPEGArithmeticDecoder;

typedef struct WinZipJPEGContext
{
    int     i;
    int32_t dlrm;  // difference between lrm and lr
    uint8_t mps;   // most probable symbol value - 0 or 1
    uint8_t k;     // least probable symbol count
} WinZipJPEGContext;

void InitializeWinZipJPEGArithmeticDecoder(WinZipJPEGArithmeticDecoder *self, WinZipJPEGReadFunction *readfunc,
                                           void *inputcontext);
void InitializeWinZipJPEGContext(WinZipJPEGContext *self);
void InitializeWinZipJPEGContexts(WinZipJPEGContext *first, size_t bytes);
void InitializeFixedWinZipJPEGContext(WinZipJPEGContext *self);

int NextBitFromWinZipJPEGArithmeticDecoder(WinZipJPEGArithmeticDecoder *self, WinZipJPEGContext *context);

void FlushWinZipJPEGArithmeticDecoder(WinZipJPEGArithmeticDecoder *self);

static inline bool WinZipJPEGArithmeticDecoderEncounteredEOF(WinZipJPEGArithmeticDecoder *self) { return self->eof; }

#endif