/*
 * Copyright (c) 2001-2003, David Janssens
 * Copyright (c) 2002-2003, Yannick Verschueren
 * Copyright (c) 2003-2005, Francois Devaux and Antonin Descampe
 * Copyright (c) 2005, Hervé Drolon, FreeImage Team
 * Copyright (c) 2002-2005, Communications and remote sensing Laboratory, Universite catholique de Louvain, Belgium
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS `AS IS'
 * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
 * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
 * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
 * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
 * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
 * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 */

#include "opj_includes.h"

/** @defgroup MQC MQC - Implementation of an MQ-Coder */
/*@{*/

/** @name Local static functions */
/*@{*/

/**
Output a byte, doing bit-stuffing if necessary.
After a 0xff byte, the next byte must be smaller than 0x90.
@param mqc MQC handle
*/
static void mqc_byteout(opj_mqc_t *mqc);
/**
Renormalize mqc->a and mqc->c while encoding, so that mqc->a stays between 0x8000 and 0x10000
@param mqc MQC handle
*/
static void mqc_renorme(opj_mqc_t *mqc);
/**
Encode the most probable symbol
@param mqc MQC handle
*/
static void mqc_codemps(opj_mqc_t *mqc);
/**
Encode the most least symbol
@param mqc MQC handle
*/
static void mqc_codelps(opj_mqc_t *mqc);
/**
Fill mqc->c with 1's for flushing
@param mqc MQC handle
*/
static void mqc_setbits(opj_mqc_t *mqc);
/**
FIXME: documentation ???
@param mqc MQC handle
@return 
*/
static int mqc_mpsexchange(opj_mqc_t *mqc);
/**
FIXME: documentation ???
@param mqc MQC handle
@return 
*/
static int mqc_lpsexchange(opj_mqc_t *mqc);
/**
Input a byte
@param mqc MQC handle
*/
static void mqc_bytein(opj_mqc_t *mqc);
/**
Renormalize mqc->a and mqc->c while decoding
@param mqc MQC handle
*/
static void mqc_renormd(opj_mqc_t *mqc);

/*@}*/

/*@}*/

/* <summary> */
/* This array defines all the possible states for a context. */
/* </summary> */
static opj_mqc_state_t mqc_states[47 * 2] = {
  {0x5601, 0, &mqc_states[2], &mqc_states[3]},
  {0x5601, 1, &mqc_states[3], &mqc_states[2]},
  {0x3401, 0, &mqc_states[4], &mqc_states[12]},
  {0x3401, 1, &mqc_states[5], &mqc_states[13]},
  {0x1801, 0, &mqc_states[6], &mqc_states[18]},
  {0x1801, 1, &mqc_states[7], &mqc_states[19]},
  {0x0ac1, 0, &mqc_states[8], &mqc_states[24]},
  {0x0ac1, 1, &mqc_states[9], &mqc_states[25]},
  {0x0521, 0, &mqc_states[10], &mqc_states[58]},
  {0x0521, 1, &mqc_states[11], &mqc_states[59]},
  {0x0221, 0, &mqc_states[76], &mqc_states[66]},
  {0x0221, 1, &mqc_states[77], &mqc_states[67]},
  {0x5601, 0, &mqc_states[14], &mqc_states[13]},
  {0x5601, 1, &mqc_states[15], &mqc_states[12]},
  {0x5401, 0, &mqc_states[16], &mqc_states[28]},
  {0x5401, 1, &mqc_states[17], &mqc_states[29]},
  {0x4801, 0, &mqc_states[18], &mqc_states[28]},
  {0x4801, 1, &mqc_states[19], &mqc_states[29]},
  {0x3801, 0, &mqc_states[20], &mqc_states[28]},
  {0x3801, 1, &mqc_states[21], &mqc_states[29]},
  {0x3001, 0, &mqc_states[22], &mqc_states[34]},
  {0x3001, 1, &mqc_states[23], &mqc_states[35]},
  {0x2401, 0, &mqc_states[24], &mqc_states[36]},
  {0x2401, 1, &mqc_states[25], &mqc_states[37]},
  {0x1c01, 0, &mqc_states[26], &mqc_states[40]},
  {0x1c01, 1, &mqc_states[27], &mqc_states[41]},
  {0x1601, 0, &mqc_states[58], &mqc_states[42]},
  {0x1601, 1, &mqc_states[59], &mqc_states[43]},
  {0x5601, 0, &mqc_states[30], &mqc_states[29]},
  {0x5601, 1, &mqc_states[31], &mqc_states[28]},
  {0x5401, 0, &mqc_states[32], &mqc_states[28]},
  {0x5401, 1, &mqc_states[33], &mqc_states[29]},
  {0x5101, 0, &mqc_states[34], &mqc_states[30]},
  {0x5101, 1, &mqc_states[35], &mqc_states[31]},
  {0x4801, 0, &mqc_states[36], &mqc_states[32]},
  {0x4801, 1, &mqc_states[37], &mqc_states[33]},
  {0x3801, 0, &mqc_states[38], &mqc_states[34]},
  {0x3801, 1, &mqc_states[39], &mqc_states[35]},
  {0x3401, 0, &mqc_states[40], &mqc_states[36]},
  {0x3401, 1, &mqc_states[41], &mqc_states[37]},
  {0x3001, 0, &mqc_states[42], &mqc_states[38]},
  {0x3001, 1, &mqc_states[43], &mqc_states[39]},
  {0x2801, 0, &mqc_states[44], &mqc_states[38]},
  {0x2801, 1, &mqc_states[45], &mqc_states[39]},
  {0x2401, 0, &mqc_states[46], &mqc_states[40]},
  {0x2401, 1, &mqc_states[47], &mqc_states[41]},
  {0x2201, 0, &mqc_states[48], &mqc_states[42]},
  {0x2201, 1, &mqc_states[49], &mqc_states[43]},
  {0x1c01, 0, &mqc_states[50], &mqc_states[44]},
  {0x1c01, 1, &mqc_states[51], &mqc_states[45]},
  {0x1801, 0, &mqc_states[52], &mqc_states[46]},
  {0x1801, 1, &mqc_states[53], &mqc_states[47]},
  {0x1601, 0, &mqc_states[54], &mqc_states[48]},
  {0x1601, 1, &mqc_states[55], &mqc_states[49]},
  {0x1401, 0, &mqc_states[56], &mqc_states[50]},
  {0x1401, 1, &mqc_states[57], &mqc_states[51]},
  {0x1201, 0, &mqc_states[58], &mqc_states[52]},
  {0x1201, 1, &mqc_states[59], &mqc_states[53]},
  {0x1101, 0, &mqc_states[60], &mqc_states[54]},
  {0x1101, 1, &mqc_states[61], &mqc_states[55]},
  {0x0ac1, 0, &mqc_states[62], &mqc_states[56]},
  {0x0ac1, 1, &mqc_states[63], &mqc_states[57]},
  {0x09c1, 0, &mqc_states[64], &mqc_states[58]},
  {0x09c1, 1, &mqc_states[65], &mqc_states[59]},
  {0x08a1, 0, &mqc_states[66], &mqc_states[60]},
  {0x08a1, 1, &mqc_states[67], &mqc_states[61]},
  {0x0521, 0, &mqc_states[68], &mqc_states[62]},
  {0x0521, 1, &mqc_states[69], &mqc_states[63]},
  {0x0441, 0, &mqc_states[70], &mqc_states[64]},
  {0x0441, 1, &mqc_states[71], &mqc_states[65]},
  {0x02a1, 0, &mqc_states[72], &mqc_states[66]},
  {0x02a1, 1, &mqc_states[73], &mqc_states[67]},
  {0x0221, 0, &mqc_states[74], &mqc_states[68]},
  {0x0221, 1, &mqc_states[75], &mqc_states[69]},
  {0x0141, 0, &mqc_states[76], &mqc_states[70]},
  {0x0141, 1, &mqc_states[77], &mqc_states[71]},
  {0x0111, 0, &mqc_states[78], &mqc_states[72]},
  {0x0111, 1, &mqc_states[79], &mqc_states[73]},
  {0x0085, 0, &mqc_states[80], &mqc_states[74]},
  {0x0085, 1, &mqc_states[81], &mqc_states[75]},
  {0x0049, 0, &mqc_states[82], &mqc_states[76]},
  {0x0049, 1, &mqc_states[83], &mqc_states[77]},
  {0x0025, 0, &mqc_states[84], &mqc_states[78]},
  {0x0025, 1, &mqc_states[85], &mqc_states[79]},
  {0x0015, 0, &mqc_states[86], &mqc_states[80]},
  {0x0015, 1, &mqc_states[87], &mqc_states[81]},
  {0x0009, 0, &mqc_states[88], &mqc_states[82]},
  {0x0009, 1, &mqc_states[89], &mqc_states[83]},
  {0x0005, 0, &mqc_states[90], &mqc_states[84]},
  {0x0005, 1, &mqc_states[91], &mqc_states[85]},
  {0x0001, 0, &mqc_states[90], &mqc_states[86]},
  {0x0001, 1, &mqc_states[91], &mqc_states[87]},
  {0x5601, 0, &mqc_states[92], &mqc_states[92]},
  {0x5601, 1, &mqc_states[93], &mqc_states[93]},
};

/* 
==========================================================
   local functions
==========================================================
*/

static void mqc_byteout(opj_mqc_t *mqc) {
  if (*mqc->bp == 0xff) {
    mqc->bp++;
    *mqc->bp = mqc->c >> 20;
    mqc->c &= 0xfffff;
    mqc->ct = 7;
  } else {
    if ((mqc->c & 0x8000000) == 0) {  /* ((mqc->c&0x8000000)==0) CHANGE */
      mqc->bp++;
      *mqc->bp = mqc->c >> 19;
      mqc->c &= 0x7ffff;
      mqc->ct = 8;
    } else {
      (*mqc->bp)++;
      if (*mqc->bp == 0xff) {
        mqc->c &= 0x7ffffff;
        mqc->bp++;
        *mqc->bp = mqc->c >> 20;
        mqc->c &= 0xfffff;
        mqc->ct = 7;
      } else {
        mqc->bp++;
        *mqc->bp = mqc->c >> 19;
        mqc->c &= 0x7ffff;
        mqc->ct = 8;
      }
    }
  }
}

static void mqc_renorme(opj_mqc_t *mqc) {
  do {
    mqc->a <<= 1;
    mqc->c <<= 1;
    mqc->ct--;
    if (mqc->ct == 0) {
      mqc_byteout(mqc);
    }
  } while ((mqc->a & 0x8000) == 0);
}

static void mqc_codemps(opj_mqc_t *mqc) {
  mqc->a -= (*mqc->curctx)->qeval;
  if ((mqc->a & 0x8000) == 0) {
    if (mqc->a < (*mqc->curctx)->qeval) {
      mqc->a = (*mqc->curctx)->qeval;
    } else {
      mqc->c += (*mqc->curctx)->qeval;
    }
    *mqc->curctx = (*mqc->curctx)->nmps;
    mqc_renorme(mqc);
  } else {
    mqc->c += (*mqc->curctx)->qeval;
  }
}

static void mqc_codelps(opj_mqc_t *mqc) {
  mqc->a -= (*mqc->curctx)->qeval;
  if (mqc->a < (*mqc->curctx)->qeval) {
    mqc->c += (*mqc->curctx)->qeval;
  } else {
    mqc->a = (*mqc->curctx)->qeval;
  }
  *mqc->curctx = (*mqc->curctx)->nlps;
  mqc_renorme(mqc);
}

static void mqc_setbits(opj_mqc_t *mqc) {
  unsigned int tempc = mqc->c + mqc->a;
  mqc->c |= 0xffff;
  if (mqc->c >= tempc) {
    mqc->c -= 0x8000;
  }
}

static int mqc_mpsexchange(opj_mqc_t *mqc) {
  int d;
  if (mqc->a < (*mqc->curctx)->qeval) {
    d = 1 - (*mqc->curctx)->mps;
    *mqc->curctx = (*mqc->curctx)->nlps;
  } else {
    d = (*mqc->curctx)->mps;
    *mqc->curctx = (*mqc->curctx)->nmps;
  }
  
  return d;
}

static int mqc_lpsexchange(opj_mqc_t *mqc) {
  int d;
  if (mqc->a < (*mqc->curctx)->qeval) {
    mqc->a = (*mqc->curctx)->qeval;
    d = (*mqc->curctx)->mps;
    *mqc->curctx = (*mqc->curctx)->nmps;
  } else {
    mqc->a = (*mqc->curctx)->qeval;
    d = 1 - (*mqc->curctx)->mps;
    *mqc->curctx = (*mqc->curctx)->nlps;
  }
  
  return d;
}

static void mqc_bytein(opj_mqc_t *mqc) {
  if (mqc->bp != mqc->end) {
    unsigned int c;
    if (mqc->bp + 1 != mqc->end) {
      c = *(mqc->bp + 1);
    } else {
      c = 0xff;
    }
    if (*mqc->bp == 0xff) {
      if (c > 0x8f) {
        mqc->c += 0xff00;
        mqc->ct = 8;
      } else {
        mqc->bp++;
        mqc->c += c << 9;
        mqc->ct = 7;
      }
    } else {
      mqc->bp++;
      mqc->c += c << 8;
      mqc->ct = 8;
    }
  } else {
    mqc->c += 0xff00;
    mqc->ct = 8;
  }
}

static void mqc_renormd(opj_mqc_t *mqc) {
  do {
    if (mqc->ct == 0) {
      mqc_bytein(mqc);
    }
    mqc->a <<= 1;
    mqc->c <<= 1;
    mqc->ct--;
  } while (mqc->a < 0x8000);
}

/* 
==========================================================
   MQ-Coder interface
==========================================================
*/

opj_mqc_t* mqc_create() {
  opj_mqc_t *mqc = (opj_mqc_t*)opj_malloc(sizeof(opj_mqc_t));
  return mqc;
}

void mqc_destroy(opj_mqc_t *mqc) {
  if(mqc) {
    opj_free(mqc);
  }
}

int mqc_numbytes(opj_mqc_t *mqc) {
  return mqc->bp - mqc->start;
}

void mqc_init_enc(opj_mqc_t *mqc, unsigned char *bp) {
  mqc_setcurctx(mqc, 0);
  mqc->a = 0x8000;
  mqc->c = 0;
  mqc->bp = bp - 1;
  mqc->ct = 12;
  if (*mqc->bp == 0xff) {
    mqc->ct = 13;
  }
  mqc->start = bp;
}

void mqc_setcurctx(opj_mqc_t *mqc, int ctxno) {
  mqc->curctx = &mqc->ctxs[ctxno];
}

void mqc_encode(opj_mqc_t *mqc, int d) {
  if ((*mqc->curctx)->mps == d) {
    mqc_codemps(mqc);
  } else {
    mqc_codelps(mqc);
  }
}

void mqc_flush(opj_mqc_t *mqc) {
  mqc_setbits(mqc);
  mqc->c <<= mqc->ct;
  mqc_byteout(mqc);
  mqc->c <<= mqc->ct;
  mqc_byteout(mqc);
  
  if (*mqc->bp != 0xff) {
    mqc->bp++;
  }
}

void mqc_bypass_init_enc(opj_mqc_t *mqc) {
  mqc->c = 0;
  mqc->ct = 8;
  /*if (*mqc->bp == 0xff) {
  mqc->ct = 7;
     } */
}

void mqc_bypass_enc(opj_mqc_t *mqc, int d) {
  mqc->ct--;
  mqc->c = mqc->c + (d << mqc->ct);
  if (mqc->ct == 0) {
    mqc->bp++;
    *mqc->bp = mqc->c;
    mqc->ct = 8;
    if (*mqc->bp == 0xff) {
      mqc->ct = 7;
    }
    mqc->c = 0;
  }
}

int mqc_bypass_flush_enc(opj_mqc_t *mqc) {
  unsigned char bit_padding;
  
  bit_padding = 0;
  
  if (mqc->ct != 0) {
    while (mqc->ct > 0) {
      mqc->ct--;
      mqc->c += bit_padding << mqc->ct;
      bit_padding = (bit_padding + 1) & 0x01;
    }
    mqc->bp++;
    *mqc->bp = mqc->c;
    mqc->ct = 8;
    mqc->c = 0;
  }
  
  return 1;
}

void mqc_reset_enc(opj_mqc_t *mqc) {
  mqc_resetstates(mqc);
  mqc_setstate(mqc, 18, 0, 46);
  mqc_setstate(mqc, 0, 0, 3);
  mqc_setstate(mqc, 1, 0, 4);
}

int mqc_restart_enc(opj_mqc_t *mqc) {
  int correction = 1;
  
  /* <flush part> */
  int n = 27 - 15 - mqc->ct;
  mqc->c <<= mqc->ct;
  while (n > 0) {
    mqc_byteout(mqc);
    n -= mqc->ct;
    mqc->c <<= mqc->ct;
  }
  mqc_byteout(mqc);
  
  return correction;
}

void mqc_restart_init_enc(opj_mqc_t *mqc) {
  /* <Re-init part> */
  mqc_setcurctx(mqc, 0);
  mqc->a = 0x8000;
  mqc->c = 0;
  mqc->ct = 12;
  mqc->bp--;
  if (*mqc->bp == 0xff) {
    mqc->ct = 13;
  }
}

void mqc_erterm_enc(opj_mqc_t *mqc) {
  int k = 11 - mqc->ct + 1;
  
  while (k > 0) {
    mqc->c <<= mqc->ct;
    mqc->ct = 0;
    mqc_byteout(mqc);
    k -= mqc->ct;
  }
  
  if (*mqc->bp != 0xff) {
    mqc_byteout(mqc);
  }
}

void mqc_segmark_enc(opj_mqc_t *mqc) {
  int i;
  mqc_setcurctx(mqc, 18);
  
  for (i = 1; i < 5; i++) {
    mqc_encode(mqc, i % 2);
  }
}

void mqc_init_dec(opj_mqc_t *mqc, unsigned char *bp, int len) {
  mqc_setcurctx(mqc, 0);
  mqc->start = bp;
  mqc->end = bp + len;
  mqc->bp = bp;
  if (len==0) mqc->c = 0xff << 16;
  else mqc->c = *mqc->bp << 16;
  mqc_bytein(mqc);
  mqc->c <<= 7;
  mqc->ct -= 7;
  mqc->a = 0x8000;
}

int mqc_decode(opj_mqc_t *mqc) {
  int d;
  mqc->a -= (*mqc->curctx)->qeval;
  if ((mqc->c >> 16) < (*mqc->curctx)->qeval) {
    d = mqc_lpsexchange(mqc);
    mqc_renormd(mqc);
  } else {
    mqc->c -= (*mqc->curctx)->qeval << 16;
    if ((mqc->a & 0x8000) == 0) {
      d = mqc_mpsexchange(mqc);
      mqc_renormd(mqc);
    } else {
      d = (*mqc->curctx)->mps;
    }
  }

  return d;
}

void mqc_resetstates(opj_mqc_t *mqc) {
  int i;
  for (i = 0; i < MQC_NUMCTXS; i++) {
    mqc->ctxs[i] = mqc_states;
  }
}

void mqc_setstate(opj_mqc_t *mqc, int ctxno, int msb, int prob) {
  mqc->ctxs[ctxno] = &mqc_states[msb + (prob << 1)];
}


