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tinyjpeg.c

/*
 * Small jpeg decoder library
 *
 * Copyright (c) 2006, Luc Saillard <luc@saillard.org>
 * All rights reserved.
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions are met:
 *
 * - Redistributions of source code must retain the above copyright notice,
 *  this list of conditions and the following disclaimer.
 *
 * - 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.
 *
 * - Neither the name of the author nor the names of its contributors may be
 *  used to endorse or promote products derived from this software without
 *  specific prior written permission.
 *
 * 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 <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <stdint.h>
#include <errno.h>

#include "tinyjpeg.h"
#include "tinyjpeg-internal.h"

enum std_markers {
   DQT  = 0xDB, /* Define Quantization Table */
   SOF  = 0xC0, /* Start of Frame (size information) */
   DHT  = 0xC4, /* Huffman Table */
   SOI  = 0xD8, /* Start of Image */
   SOS  = 0xDA, /* Start of Scan */
   RST  = 0xD0, /* Reset Marker d0 -> .. */
   RST7 = 0xD7, /* Reset Marker .. -> d7 */
   EOI  = 0xD9, /* End of Image */
   DRI  = 0xDD, /* Define Restart Interval */
   APP0 = 0xE0,
};

#define cY  0
#define cCb 1
#define cCr 2

#define BLACK_Y 0
#define BLACK_U 127
#define BLACK_V 127

#if DEBUG
#if LOG2FILE

#define trace(fmt, args...) do { \
   FILE *f = fopen("/tmp/jpeg.log", "a"); \
   fprintf(f, fmt, ## args); \
   fflush(f); \
   fclose(f); \
} while(0)

#else

#define trace(fmt, args...) do { \
   fprintf(stderr, fmt, ## args); \
   fflush(stderr); \
} while(0)
#endif

#else
#define trace(fmt, args...) do { } while (0)
#endif

#define error(fmt, args...) do { \
   snprintf(priv->error_string, sizeof(priv->error_string), fmt, ## args); \
   return -1; \
} while(0)


#if 0
static char *print_bits(unsigned int value, char *bitstr)
{
  int i, j;
  i=31;
  while (i>0)
   {
     if (value & (1UL<<i))
       break;
     i--;
   }
  j=0;
  while (i>=0)
   {
     bitstr[j++] = (value & (1UL<<i))?'1':'0';
     i--;
   }
  bitstr[j] = 0;
  return bitstr;
}

static void print_next_16bytes(int offset, const unsigned char *stream)
{
  trace("%4.4x: %2.2x %2.2x %2.2x %2.2x %2.2x %2.2x %2.2x %2.2x %2.2x %2.2x %2.2x %2.2x %2.2x %2.2x %2.2x %2.2x\n",
      offset,
      stream[0], stream[1], stream[2], stream[3],
      stream[4], stream[5], stream[6], stream[7],
      stream[8], stream[9], stream[10], stream[11],
      stream[12], stream[13], stream[14], stream[15]);
}

#endif


static const unsigned char zigzag[64] =
{
   0,  1,  5,  6, 14, 15, 27, 28,
   2,  4,  7, 13, 16, 26, 29, 42,
   3,  8, 12, 17, 25, 30, 41, 43,
   9, 11, 18, 24, 31, 40, 44, 53,
  10, 19, 23, 32, 39, 45, 52, 54,
  20, 22, 33, 38, 46, 51, 55, 60,
  21, 34, 37, 47, 50, 56, 59, 61,
  35, 36, 48, 49, 57, 58, 62, 63
};

/* Set up the standard Huffman tables (cf. JPEG standard section K.3) */
/* IMPORTANT: these are only valid for 8-bit data precision! */
static const unsigned char bits_dc_luminance[17] =
{
  0, 0, 1, 5, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0, 0, 0
};
static const unsigned char val_dc_luminance[] =
{
  0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11
};

static const unsigned char bits_dc_chrominance[17] =
{
  0, 0, 3, 1, 1, 1, 1, 1, 1, 1, 1, 1, 0, 0, 0, 0, 0
};
static const unsigned char val_dc_chrominance[] =
{
  0, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11
};

static const unsigned char bits_ac_luminance[17] =
{
  0, 0, 2, 1, 3, 3, 2, 4, 3, 5, 5, 4, 4, 0, 0, 1, 0x7d
};
static const unsigned char val_ac_luminance[] =
{
  0x01, 0x02, 0x03, 0x00, 0x04, 0x11, 0x05, 0x12,
  0x21, 0x31, 0x41, 0x06, 0x13, 0x51, 0x61, 0x07,
  0x22, 0x71, 0x14, 0x32, 0x81, 0x91, 0xa1, 0x08,
  0x23, 0x42, 0xb1, 0xc1, 0x15, 0x52, 0xd1, 0xf0,
  0x24, 0x33, 0x62, 0x72, 0x82, 0x09, 0x0a, 0x16,
  0x17, 0x18, 0x19, 0x1a, 0x25, 0x26, 0x27, 0x28,
  0x29, 0x2a, 0x34, 0x35, 0x36, 0x37, 0x38, 0x39,
  0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48, 0x49,
  0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58, 0x59,
  0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68, 0x69,
  0x6a, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78, 0x79,
  0x7a, 0x83, 0x84, 0x85, 0x86, 0x87, 0x88, 0x89,
  0x8a, 0x92, 0x93, 0x94, 0x95, 0x96, 0x97, 0x98,
  0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5, 0xa6, 0xa7,
  0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4, 0xb5, 0xb6,
  0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3, 0xc4, 0xc5,
  0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2, 0xd3, 0xd4,
  0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda, 0xe1, 0xe2,
  0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9, 0xea,
  0xf1, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8,
  0xf9, 0xfa
};

static const unsigned char bits_ac_chrominance[17] =
{
  0, 0, 2, 1, 2, 4, 4, 3, 4, 7, 5, 4, 4, 0, 1, 2, 0x77
};

static const unsigned char val_ac_chrominance[] =
{
  0x00, 0x01, 0x02, 0x03, 0x11, 0x04, 0x05, 0x21,
  0x31, 0x06, 0x12, 0x41, 0x51, 0x07, 0x61, 0x71,
  0x13, 0x22, 0x32, 0x81, 0x08, 0x14, 0x42, 0x91,
  0xa1, 0xb1, 0xc1, 0x09, 0x23, 0x33, 0x52, 0xf0,
  0x15, 0x62, 0x72, 0xd1, 0x0a, 0x16, 0x24, 0x34,
  0xe1, 0x25, 0xf1, 0x17, 0x18, 0x19, 0x1a, 0x26,
  0x27, 0x28, 0x29, 0x2a, 0x35, 0x36, 0x37, 0x38,
  0x39, 0x3a, 0x43, 0x44, 0x45, 0x46, 0x47, 0x48,
  0x49, 0x4a, 0x53, 0x54, 0x55, 0x56, 0x57, 0x58,
  0x59, 0x5a, 0x63, 0x64, 0x65, 0x66, 0x67, 0x68,
  0x69, 0x6a, 0x73, 0x74, 0x75, 0x76, 0x77, 0x78,
  0x79, 0x7a, 0x82, 0x83, 0x84, 0x85, 0x86, 0x87,
  0x88, 0x89, 0x8a, 0x92, 0x93, 0x94, 0x95, 0x96,
  0x97, 0x98, 0x99, 0x9a, 0xa2, 0xa3, 0xa4, 0xa5,
  0xa6, 0xa7, 0xa8, 0xa9, 0xaa, 0xb2, 0xb3, 0xb4,
  0xb5, 0xb6, 0xb7, 0xb8, 0xb9, 0xba, 0xc2, 0xc3,
  0xc4, 0xc5, 0xc6, 0xc7, 0xc8, 0xc9, 0xca, 0xd2,
  0xd3, 0xd4, 0xd5, 0xd6, 0xd7, 0xd8, 0xd9, 0xda,
  0xe2, 0xe3, 0xe4, 0xe5, 0xe6, 0xe7, 0xe8, 0xe9,
  0xea, 0xf2, 0xf3, 0xf4, 0xf5, 0xf6, 0xf7, 0xf8,
  0xf9, 0xfa
};

const unsigned char pixart_quantization[][64] = {
  {
  0x07, 0x07, 0x08, 0x0a, 0x09, 0x07, 0x0d, 0x0b,
  0x0c, 0x0d, 0x11, 0x10, 0x0f, 0x12, 0x17, 0x27,
  0x1a, 0x18, 0x16, 0x16, 0x18, 0x31, 0x23, 0x25,
  0x1d, 0x28, 0x3a, 0x33, 0x3d, 0x3c, 0x39, 0x33,
  0x38, 0x37, 0x40, 0x48, 0x5c, 0x4e, 0x40, 0x44,
  0x57, 0x45, 0x37, 0x38, 0x50, 0x6d, 0x51, 0x57,
  0x5f, 0x62, 0x67, 0x68, 0x67, 0x3e, 0x4d, 0x71,
  0x79, 0x70, 0x64, 0x78, 0x5c, 0x65, 0x67, 0x63,
  },
  {
  0x11, 0x12, 0x12, 0x18, 0x15, 0x18, 0x2f, 0x1a,
  0x1a, 0x2f, 0x63, 0x42, 0x38, 0x42, 0x63, 0x63,
  0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63,
  0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63,
  0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63,
  0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63,
  0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63,
  0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63, 0x63,
  },
};

/*
 * 4 functions to manage the stream
 *
 *  fill_nbits: put at least nbits in the reservoir of bits.
 *              But convert any 0xff,0x00 into 0xff
 *  get_nbits: read nbits from the stream, and put it in result,
 *             bits is removed from the stream and the reservoir is filled
 *             automaticaly. The result is signed according to the number of
 *             bits.
 *  look_nbits: read nbits from the stream without marking as read.
 *  skip_nbits: read nbits from the stream but do not return the result.
 *
 * stream: current pointer in the jpeg data (read bytes per bytes)
 * nbits_in_reservoir: number of bits filled into the reservoir
 * reservoir: register that contains bits information. Only nbits_in_reservoir
 *            is valid.
 *                          nbits_in_reservoir
 *                        <--    17 bits    -->
 *            Ex: 0000 0000 1010 0000 1111 0000   <== reservoir
 *                        ^
 *                        bit 1
 *            To get two bits from this example
 *                 result = (reservoir >> 15) & 3
 *
 */
#define fill_nbits(reservoir,nbits_in_reservoir,stream,nbits_wanted) do { \
   while (nbits_in_reservoir<nbits_wanted) \
    { \
      unsigned char c; \
      if (stream >= priv->stream_end) { \
      snprintf(priv->error_string, sizeof(priv->error_string), \
        "fill_nbits error: need %u more bits\n", \
        nbits_wanted - nbits_in_reservoir); \
      longjmp(priv->jump_state, -EIO); \
      } \
      c = *stream++; \
      reservoir <<= 8; \
      if (c == 0xff && *stream == 0x00) \
      stream++; \
      reservoir |= c; \
      nbits_in_reservoir+=8; \
    } \
}  while(0);

/* Signed version !!!! */
#define get_nbits(reservoir,nbits_in_reservoir,stream,nbits_wanted,result) do { \
   fill_nbits(reservoir,nbits_in_reservoir,stream,(nbits_wanted)); \
   result = ((reservoir)>>(nbits_in_reservoir-(nbits_wanted))); \
   nbits_in_reservoir -= (nbits_wanted);  \
   reservoir &= ((1U<<nbits_in_reservoir)-1); \
   if ((unsigned int)result < (1UL<<((nbits_wanted)-1))) \
       result += (0xFFFFFFFFUL<<(nbits_wanted))+1; \
}  while(0);

#define look_nbits(reservoir,nbits_in_reservoir,stream,nbits_wanted,result) do { \
   fill_nbits(reservoir,nbits_in_reservoir,stream,(nbits_wanted)); \
   result = ((reservoir)>>(nbits_in_reservoir-(nbits_wanted))); \
}  while(0);

/* To speed up the decoding, we assume that the reservoir have enough bit
 * slow version:
 * #define skip_nbits(reservoir,nbits_in_reservoir,stream,nbits_wanted) do { \
 *   fill_nbits(reservoir,nbits_in_reservoir,stream,(nbits_wanted)); \
 *   nbits_in_reservoir -= (nbits_wanted); \
 *   reservoir &= ((1U<<nbits_in_reservoir)-1); \
 * }  while(0);
 */
#define skip_nbits(reservoir,nbits_in_reservoir,stream,nbits_wanted) do { \
   nbits_in_reservoir -= (nbits_wanted); \
   reservoir &= ((1U<<nbits_in_reservoir)-1); \
}  while(0);


/* Special Pixart versions of the *_nbits functions, these remove the special
   ff ff ff xx sequences pixart cams insert from the bitstream */
#define pixart_fill_nbits(reservoir,nbits_in_reservoir,stream,nbits_wanted) \
do { \
   while (nbits_in_reservoir<nbits_wanted) \
    { \
      unsigned char c; \
      if (stream >= priv->stream_end) { \
      snprintf(priv->error_string, sizeof(priv->error_string), \
        "fill_nbits error: need %u more bits\n", \
        nbits_wanted - nbits_in_reservoir); \
      longjmp(priv->jump_state, -EIO); \
      } \
      c = *stream++; \
      reservoir <<= 8; \
      if (c == 0xff) { \
      switch (stream[0]) { \
        case 0x00: \
          stream++; \
          break; \
        case 0xd9: /* EOF marker */ \
          stream++; \
          if (stream != priv->stream_end) { \
            snprintf(priv->error_string, sizeof(priv->error_string), \
            "Pixart JPEG error: premature EOF\n"); \
            longjmp(priv->jump_state, -EIO); \
          } \
          break; \
        case 0xff: \
          if (stream[1] == 0xff && (stream[2] < 7 || stream[2] == 0xff)) { \
            stream += 3; \
            c = *stream++; \
            break; \
          } \
          /* Error fall through */ \
        default: \
          snprintf(priv->error_string, sizeof(priv->error_string), \
            "Pixart JPEG error: invalid JPEG marker: 0xff 0x%02x 0x%02x 0x%02x\n", \
            (unsigned int)stream[0], (unsigned int)stream[1], \
            (unsigned int)stream[2]); \
          longjmp(priv->jump_state, -EIO); \
      } \
      } \
      reservoir |= c; \
      nbits_in_reservoir+=8; \
    } \
}  while(0);

/* Signed version !!!! */
#define pixart_get_nbits(reservoir,nbits_in_reservoir,stream,nbits_wanted,result) \
do { \
   pixart_fill_nbits(reservoir,nbits_in_reservoir,stream,(nbits_wanted)); \
   result = ((reservoir)>>(nbits_in_reservoir-(nbits_wanted))); \
   nbits_in_reservoir -= (nbits_wanted);  \
   reservoir &= ((1U<<nbits_in_reservoir)-1); \
   if ((unsigned int)result < (1UL<<((nbits_wanted)-1))) \
       result += (0xFFFFFFFFUL<<(nbits_wanted))+1; \
}  while(0);

#define pixart_look_nbits(reservoir,nbits_in_reservoir,stream,nbits_wanted,result) \
do { \
   pixart_fill_nbits(reservoir,nbits_in_reservoir,stream,(nbits_wanted)); \
   result = ((reservoir)>>(nbits_in_reservoir-(nbits_wanted))); \
}  while(0);

/* Note skip_nbits is identical for both */


#define be16_to_cpu(x) (((x)[0]<<8)|(x)[1])

static void resync(struct jdec_private *priv);

/**
 * Get the next (valid) huffman code in the stream.
 *
 * To speedup the procedure, we look HUFFMAN_HASH_NBITS bits and the code is
 * lower than HUFFMAN_HASH_NBITS we have automaticaly the length of the code
 * and the value by using two lookup table.
 * Else if the value is not found, just search (linear) into an array for each
 * bits is the code is present.
 *
 * If the code is not present for any reason, -1 is return.
 */
static int get_next_huffman_code(struct jdec_private *priv, struct huffman_table *huffman_table)
{
  int value, hcode;
  unsigned int extra_nbits, nbits;
  uint16_t *slowtable;

  look_nbits(priv->reservoir, priv->nbits_in_reservoir, priv->stream, HUFFMAN_HASH_NBITS, hcode);
  value = huffman_table->lookup[hcode];
  if (value >= 0)
  {
     unsigned int code_size = huffman_table->code_size[value];
     skip_nbits(priv->reservoir, priv->nbits_in_reservoir, priv->stream, code_size);
     return value;
  }

  /* Decode more bits each time ... */
  for (extra_nbits=0; extra_nbits<16-HUFFMAN_HASH_NBITS; extra_nbits++)
   {
     nbits = HUFFMAN_HASH_NBITS + 1 + extra_nbits;

     look_nbits(priv->reservoir, priv->nbits_in_reservoir, priv->stream, nbits, hcode);
     slowtable = huffman_table->slowtable[extra_nbits];
     /* Search if the code is in this array */
     while (slowtable[0]) {
      if (slowtable[0] == hcode) {
         skip_nbits(priv->reservoir, priv->nbits_in_reservoir, priv->stream, nbits);
         return slowtable[1];
      }
      slowtable+=2;
     }
   }
  snprintf(priv->error_string, sizeof(priv->error_string),
    "unknown huffman code: %08x\n", (unsigned int)hcode);
  longjmp(priv->jump_state, -EIO);
  return 0;
}

/* identical as above but with *_nbits replaced with pixart_*_nbits */
static int pixart_get_next_huffman_code(struct jdec_private *priv,
  struct huffman_table *huffman_table)
{
  int value, hcode;
  unsigned int extra_nbits, nbits;
  uint16_t *slowtable;

  pixart_look_nbits(priv->reservoir, priv->nbits_in_reservoir, priv->stream, HUFFMAN_HASH_NBITS, hcode);
  value = huffman_table->lookup[hcode];
  if (value >= 0)
  {
     unsigned int code_size = huffman_table->code_size[value];
     skip_nbits(priv->reservoir, priv->nbits_in_reservoir, priv->stream, code_size);
     return value;
  }

  /* Decode more bits each time ... */
  for (extra_nbits=0; extra_nbits<16-HUFFMAN_HASH_NBITS; extra_nbits++)
   {
     nbits = HUFFMAN_HASH_NBITS + 1 + extra_nbits;

     pixart_look_nbits(priv->reservoir, priv->nbits_in_reservoir, priv->stream, nbits, hcode);
     slowtable = huffman_table->slowtable[extra_nbits];
     /* Search if the code is in this array */
     while (slowtable[0]) {
      if (slowtable[0] == hcode) {
         skip_nbits(priv->reservoir, priv->nbits_in_reservoir, priv->stream, nbits);
         return slowtable[1];
      }
      slowtable+=2;
     }
   }
  snprintf(priv->error_string, sizeof(priv->error_string),
    "unknown huffman code: %08x\n", (unsigned int)hcode);
  longjmp(priv->jump_state, -EIO);
  return 0;
}



/**
 *
 * Decode a single block that contains the DCT coefficients.
 * The table coefficients is already dezigzaged at the end of the operation.
 *
 */
static void process_Huffman_data_unit(struct jdec_private *priv, int component)
{
  unsigned char j;
  unsigned int huff_code;
  unsigned char size_val, count_0;

  struct component *c = &priv->component_infos[component];
  short int DCT[64];

  /* Initialize the DCT coef table */
  memset(DCT, 0, sizeof(DCT));

  /* DC coefficient decoding */
  huff_code = get_next_huffman_code(priv, c->DC_table);
  if (huff_code) {
     get_nbits(priv->reservoir, priv->nbits_in_reservoir, priv->stream, huff_code, DCT[0]);
     DCT[0] += c->previous_DC;
     c->previous_DC = DCT[0];
  } else {
     DCT[0] = c->previous_DC;
  }


  /* AC coefficient decoding */
  j = 1;
  while (j<64)
   {
     huff_code = get_next_huffman_code(priv, c->AC_table);

     size_val = huff_code & 0xF;
     count_0 = huff_code >> 4;

     if (size_val == 0)
      { /* RLE */
      if (count_0 == 0)
        break;    /* EOB found, go out */
      else if (count_0 == 0xF)
        j += 16;  /* skip 16 zeros */
      }
     else
      {
      j += count_0;     /* skip count_0 zeroes */
      if (j < 64) {
        get_nbits(priv->reservoir, priv->nbits_in_reservoir, priv->stream, size_val, DCT[j]);
        j++;
      }
      }
   }

  if (j > 64) {
    snprintf(priv->error_string, sizeof(priv->error_string),
      "error: more then 63 AC components (%d) in huffman unit\n", (int)j);
    longjmp(priv->jump_state, -EIO);
  }

  for (j = 0; j < 64; j++)
    c->DCT[j] = DCT[zigzag[j]];
}

/* identical as above both with *_nbits replaced with pixart_*_nbits */
static void pixart_process_Huffman_data_unit(struct jdec_private *priv, int component)
{
  unsigned char j;
  unsigned int huff_code;
  unsigned char size_val, count_0;

  struct component *c = &priv->component_infos[component];
  short int DCT[64];

  /* Initialize the DCT coef table */
  memset(DCT, 0, sizeof(DCT));

  /* DC coefficient decoding */
  huff_code = pixart_get_next_huffman_code(priv, c->DC_table);
  if (huff_code) {
     pixart_get_nbits(priv->reservoir, priv->nbits_in_reservoir, priv->stream, huff_code, DCT[0]);
     DCT[0] += c->previous_DC;
     c->previous_DC = DCT[0];
  } else {
     DCT[0] = c->previous_DC;
  }


  /* AC coefficient decoding */
  j = 1;
  while (j<64)
   {
     huff_code = pixart_get_next_huffman_code(priv, c->AC_table);

     size_val = huff_code & 0xF;
     count_0 = huff_code >> 4;

     if (size_val == 0)
      { /* RLE */
      if (count_0 == 0)
        break;    /* EOB found, go out */
      else if (count_0 == 0xF)
        j += 16;  /* skip 16 zeros */
      }
     else
      {
      j += count_0;     /* skip count_0 zeroes */
      if (j < 64 ) {
        pixart_get_nbits(priv->reservoir, priv->nbits_in_reservoir, priv->stream, size_val, DCT[j]);
        j++;
      }
      }
   }

  if (j > 64) {
    snprintf(priv->error_string, sizeof(priv->error_string),
      "error: more then 63 AC components (%d) in huffman unit\n", (int)j);
    longjmp(priv->jump_state, -EIO);
  }

  for (j = 0; j < 64; j++)
    c->DCT[j] = DCT[zigzag[j]];
}


/*
 * Takes two array of bits, and build the huffman table for size, and code
 *
 * lookup will return the symbol if the code is less or equal than HUFFMAN_HASH_NBITS.
 * code_size will be used to known how many bits this symbol is encoded.
 * slowtable will be used when the first lookup didn't give the result.
 */
static int build_huffman_table(struct jdec_private *priv, const unsigned char *bits, const unsigned char *vals, struct huffman_table *table)
{
  unsigned int i, j, code, code_size, val, nbits;
  unsigned char huffsize[257], *hz;
  unsigned int huffcode[257], *hc;
  int next_free_entry;
  int slowtable_used[16-HUFFMAN_HASH_NBITS];

  /*
   * Build a temp array
   *   huffsize[X] => numbers of bits to write vals[X]
   */
  hz = huffsize;
  for (i=1; i<=16; i++)
   {
     for (j=1; j<=bits[i]; j++)
       *hz++ = i;
   }
  *hz = 0;

  memset(table->lookup, 0xff, sizeof(table->lookup));
  for (i=0; i<(16-HUFFMAN_HASH_NBITS); i++)
    slowtable_used[i] = 0;

  /* Build a temp array
   *   huffcode[X] => code used to write vals[X]
   */
  code = 0;
  hc = huffcode;
  hz = huffsize;
  nbits = *hz;
  while (*hz)
   {
     while (*hz == nbits) {
      *hc++ = code++;
      hz++;
     }
     code <<= 1;
     nbits++;
   }

  /*
   * Build the lookup table, and the slowtable if needed.
   */
  next_free_entry = -1;
  for (i=0; huffsize[i]; i++)
   {
     val = vals[i];
     code = huffcode[i];
     code_size = huffsize[i];

     trace("val=%2.2x code=%8.8x codesize=%2.2d\n", i, code, code_size);

     table->code_size[val] = code_size;
     if (code_size <= HUFFMAN_HASH_NBITS)
      {
      /*
       * Good: val can be put in the lookup table, so fill all value of this
       * column with value val
       */
      int repeat = 1UL<<(HUFFMAN_HASH_NBITS - code_size);
      code <<= HUFFMAN_HASH_NBITS - code_size;
      while ( repeat-- )
        table->lookup[code++] = val;

      }
     else
      {
      /* Perhaps sorting the array will be an optimization */
      int slowtable_index = code_size-HUFFMAN_HASH_NBITS-1;

      if (slowtable_used[slowtable_index] == 254)
        error("slow Huffman table overflow\n");

      table->slowtable[slowtable_index][slowtable_used[slowtable_index]]
        = code;
      table->slowtable[slowtable_index][slowtable_used[slowtable_index] + 1]
        = val;
      slowtable_used[slowtable_index] += 2;
      }
   }

   for (i=0; i<(16-HUFFMAN_HASH_NBITS); i++)
     table->slowtable[i][slowtable_used[i]] = 0;

   return 0;
}

static int build_default_huffman_tables(struct jdec_private *priv)
{
  if (   (priv->flags & TINYJPEG_FLAGS_MJPEG_TABLE)
      && priv->default_huffman_table_initialized)
    return 0;

  if (build_huffman_table(priv, bits_dc_luminance, val_dc_luminance, &priv->HTDC[0]))
    return -1;
  if (build_huffman_table(priv, bits_ac_luminance, val_ac_luminance, &priv->HTAC[0]))
    return -1;

  if (build_huffman_table(priv, bits_dc_chrominance, val_dc_chrominance, &priv->HTDC[1]))
    return -1;
  if (build_huffman_table(priv, bits_ac_chrominance, val_ac_chrominance, &priv->HTAC[1]))
    return -1;

  priv->default_huffman_table_initialized = 1;
  return 0;
}



/*******************************************************************************
 *
 * Colorspace conversion routine
 *
 *
 * Note:
 * YCbCr is defined per CCIR 601-1, except that Cb and Cr are
 * normalized to the range 0..MAXJSAMPLE rather than -0.5 .. 0.5.
 * The conversion equations to be implemented are therefore
 *      R = Y                + 1.40200 * Cr
 *      G = Y - 0.34414 * Cb - 0.71414 * Cr
 *      B = Y + 1.77200 * Cb
 *
 ******************************************************************************/

static unsigned char clamp(int i)
{
  if (i<0)
    return 0;
  else if (i>255)
    return 255;
  else
    return i;
}


/**
 *  YCrCb -> YUV420P (1x1)
 *  .---.
 *  | 1 |
 *  `---'
 */
static void YCrCB_to_YUV420P_1x1(struct jdec_private *priv)
{
  const unsigned char *s, *y;
  unsigned char *p;
  int i,j;

  p = priv->plane[0];
  y = priv->Y;
  for (i=0; i<8; i++)
   {
     memcpy(p, y, 8);
     p+=priv->width;
     y+=8;
   }

  p = priv->plane[1];
  s = priv->Cb;
  for (i=0; i<8; i+=2)
   {
     for (j=0; j<8; j+=2, s+=2)
       *p++ = *s;
     s += 8; /* Skip one line */
     p += priv->width/2 - 4;
   }

  p = priv->plane[2];
  s = priv->Cr;
  for (i=0; i<8; i+=2)
   {
     for (j=0; j<8; j+=2, s+=2)
       *p++ = *s;
     s += 8; /* Skip one line */
     p += priv->width/2 - 4;
   }
}

/**
 *  YCrCb -> YUV420P (2x1)
 *  .-------.
 *  | 1 | 2 |
 *  `-------'
 */
static void YCrCB_to_YUV420P_2x1(struct jdec_private *priv)
{
  unsigned char *p;
  const unsigned char *s, *y1;
  unsigned int i;

  p = priv->plane[0];
  y1 = priv->Y;
  for (i=0; i<8; i++)
   {
     memcpy(p, y1, 16);
     p += priv->width;
     y1 += 16;
   }

  p = priv->plane[1];
  s = priv->Cb;
  for (i=0; i<8; i+=2)
   {
     memcpy(p, s, 8);
     s += 16; /* Skip one line */
     p += priv->width/2;
   }

  p = priv->plane[2];
  s = priv->Cr;
  for (i=0; i<8; i+=2)
   {
     memcpy(p, s, 8);
     s += 16; /* Skip one line */
     p += priv->width/2;
   }
}


/**
 *  YCrCb -> YUV420P (1x2)
 *  .---.
 *  | 1 |
 *  |---|
 *  | 2 |
 *  `---'
 */
static void YCrCB_to_YUV420P_1x2(struct jdec_private *priv)
{
  const unsigned char *s, *y;
  unsigned char *p;
  int i,j;

  p = priv->plane[0];
  y = priv->Y;
  for (i=0; i<16; i++)
   {
     memcpy(p, y, 8);
     p+=priv->width;
     y+=8;
   }

  p = priv->plane[1];
  s = priv->Cb;
  for (i=0; i<8; i++)
   {
     for (j=0; j<8; j+=2, s+=2)
       *p++ = *s;
     p += priv->width/2 - 4;
   }

  p = priv->plane[2];
  s = priv->Cr;
  for (i=0; i<8; i++)
   {
     for (j=0; j<8; j+=2, s+=2)
       *p++ = *s;
     p += priv->width/2 - 4;
   }
}

/**
 *  YCrCb -> YUV420P (2x2)
 *  .-------.
 *  | 1 | 2 |
 *  |---+---|
 *  | 3 | 4 |
 *  `-------'
 */
static void YCrCB_to_YUV420P_2x2(struct jdec_private *priv)
{
  unsigned char *p;
  const unsigned char *s, *y1;
  unsigned int i;

  p = priv->plane[0];
  y1 = priv->Y;
  for (i=0; i<16; i++)
   {
     memcpy(p, y1, 16);
     p += priv->width;
     y1 += 16;
   }

  p = priv->plane[1];
  s = priv->Cb;
  for (i=0; i<8; i++)
   {
     memcpy(p, s, 8);
     s += 8;
     p += priv->width/2;
   }

  p = priv->plane[2];
  s = priv->Cr;
  for (i=0; i<8; i++)
   {
     memcpy(p, s, 8);
     s += 8;
     p += priv->width/2;
   }
}

/**
 *  YCrCb -> RGB24 (1x1)
 *  .---.
 *  | 1 |
 *  `---'
 */
static void YCrCB_to_RGB24_1x1(struct jdec_private *priv)
{
  const unsigned char *Y, *Cb, *Cr;
  unsigned char *p;
  int i,j;
  int offset_to_next_row;

#define SCALEBITS       10
#define ONE_HALF        (1UL << (SCALEBITS-1))
#define FIX(x)          ((int)((x) * (1UL<<SCALEBITS) + 0.5))

  p = priv->plane[0];
  Y = priv->Y;
  Cb = priv->Cb;
  Cr = priv->Cr;
  offset_to_next_row = priv->width*3 - 8*3;
  for (i=0; i<8; i++) {

    for (j=0; j<8; j++) {

       int y, cb, cr;
       int add_r, add_g, add_b;
       int r, g , b;

       y  = (*Y++) << SCALEBITS;
       cb = *Cb++ - 128;
       cr = *Cr++ - 128;
       add_r = FIX(1.40200) * cr + ONE_HALF;
       add_g = - FIX(0.34414) * cb - FIX(0.71414) * cr + ONE_HALF;
       add_b = FIX(1.77200) * cb + ONE_HALF;

       r = (y + add_r) >> SCALEBITS;
       *p++ = clamp(r);
       g = (y + add_g) >> SCALEBITS;
       *p++ = clamp(g);
       b = (y + add_b) >> SCALEBITS;
       *p++ = clamp(b);

    }

    p += offset_to_next_row;
  }

#undef SCALEBITS
#undef ONE_HALF
#undef FIX

}

/**
 *  YCrCb -> BGR24 (1x1)
 *  .---.
 *  | 1 |
 *  `---'
 */
static void YCrCB_to_BGR24_1x1(struct jdec_private *priv)
{
  const unsigned char *Y, *Cb, *Cr;
  unsigned char *p;
  int i,j;
  int offset_to_next_row;

#define SCALEBITS       10
#define ONE_HALF        (1UL << (SCALEBITS-1))
#define FIX(x)          ((int)((x) * (1UL<<SCALEBITS) + 0.5))

  p = priv->plane[0];
  Y = priv->Y;
  Cb = priv->Cb;
  Cr = priv->Cr;
  offset_to_next_row = priv->width*3 - 8*3;
  for (i=0; i<8; i++) {

    for (j=0; j<8; j++) {

       int y, cb, cr;
       int add_r, add_g, add_b;
       int r, g , b;

       y  = (*Y++) << SCALEBITS;
       cb = *Cb++ - 128;
       cr = *Cr++ - 128;
       add_r = FIX(1.40200) * cr + ONE_HALF;
       add_g = - FIX(0.34414) * cb - FIX(0.71414) * cr + ONE_HALF;
       add_b = FIX(1.77200) * cb + ONE_HALF;

       b = (y + add_b) >> SCALEBITS;
       *p++ = clamp(b);
       g = (y + add_g) >> SCALEBITS;
       *p++ = clamp(g);
       r = (y + add_r) >> SCALEBITS;
       *p++ = clamp(r);

    }

    p += offset_to_next_row;
  }

#undef SCALEBITS
#undef ONE_HALF
#undef FIX

}


/**
 *  YCrCb -> RGB24 (2x1)
 *  .-------.
 *  | 1 | 2 |
 *  `-------'
 */
static void YCrCB_to_RGB24_2x1(struct jdec_private *priv)
{
  const unsigned char *Y, *Cb, *Cr;
  unsigned char *p;
  int i,j;
  int offset_to_next_row;

#define SCALEBITS       10
#define ONE_HALF        (1UL << (SCALEBITS-1))
#define FIX(x)          ((int)((x) * (1UL<<SCALEBITS) + 0.5))

  p = priv->plane[0];
  Y = priv->Y;
  Cb = priv->Cb;
  Cr = priv->Cr;
  offset_to_next_row = priv->width*3 - 16*3;
  for (i=0; i<8; i++) {

    for (j=0; j<8; j++) {

       int y, cb, cr;
       int add_r, add_g, add_b;
       int r, g , b;

       y  = (*Y++) << SCALEBITS;
       cb = *Cb++ - 128;
       cr = *Cr++ - 128;
       add_r = FIX(1.40200) * cr + ONE_HALF;
       add_g = - FIX(0.34414) * cb - FIX(0.71414) * cr + ONE_HALF;
       add_b = FIX(1.77200) * cb + ONE_HALF;

       r = (y + add_r) >> SCALEBITS;
       *p++ = clamp(r);
       g = (y + add_g) >> SCALEBITS;
       *p++ = clamp(g);
       b = (y + add_b) >> SCALEBITS;
       *p++ = clamp(b);

       y  = (*Y++) << SCALEBITS;
       r = (y + add_r) >> SCALEBITS;
       *p++ = clamp(r);
       g = (y + add_g) >> SCALEBITS;
       *p++ = clamp(g);
       b = (y + add_b) >> SCALEBITS;
       *p++ = clamp(b);

    }

    p += offset_to_next_row;
  }

#undef SCALEBITS
#undef ONE_HALF
#undef FIX

}

/*
 *  YCrCb -> BGR24 (2x1)
 *  .-------.
 *  | 1 | 2 |
 *  `-------'
 */
static void YCrCB_to_BGR24_2x1(struct jdec_private *priv)
{
  const unsigned char *Y, *Cb, *Cr;
  unsigned char *p;
  int i,j;
  int offset_to_next_row;

#define SCALEBITS       10
#define ONE_HALF        (1UL << (SCALEBITS-1))
#define FIX(x)          ((int)((x) * (1UL<<SCALEBITS) + 0.5))

  p = priv->plane[0];
  Y = priv->Y;
  Cb = priv->Cb;
  Cr = priv->Cr;
  offset_to_next_row = priv->width*3 - 16*3;
  for (i=0; i<8; i++) {

    for (j=0; j<8; j++) {

       int y, cb, cr;
       int add_r, add_g, add_b;
       int r, g , b;

       cb = *Cb++ - 128;
       cr = *Cr++ - 128;
       add_r = FIX(1.40200) * cr + ONE_HALF;
       add_g = - FIX(0.34414) * cb - FIX(0.71414) * cr + ONE_HALF;
       add_b = FIX(1.77200) * cb + ONE_HALF;

       y  = (*Y++) << SCALEBITS;
       b = (y + add_b) >> SCALEBITS;
       *p++ = clamp(b);
       g = (y + add_g) >> SCALEBITS;
       *p++ = clamp(g);
       r = (y + add_r) >> SCALEBITS;
       *p++ = clamp(r);

       y  = (*Y++) << SCALEBITS;
       b = (y + add_b) >> SCALEBITS;
       *p++ = clamp(b);
       g = (y + add_g) >> SCALEBITS;
       *p++ = clamp(g);
       r = (y + add_r) >> SCALEBITS;
       *p++ = clamp(r);

    }

    p += offset_to_next_row;
  }

#undef SCALEBITS
#undef ONE_HALF
#undef FIX

}

/**
 *  YCrCb -> RGB24 (1x2)
 *  .---.
 *  | 1 |
 *  |---|
 *  | 2 |
 *  `---'
 */
static void YCrCB_to_RGB24_1x2(struct jdec_private *priv)
{
  const unsigned char *Y, *Cb, *Cr;
  unsigned char *p, *p2;
  int i,j;
  int offset_to_next_row;

#define SCALEBITS       10
#define ONE_HALF        (1UL << (SCALEBITS-1))
#define FIX(x)          ((int)((x) * (1UL<<SCALEBITS) + 0.5))

  p = priv->plane[0];
  p2 = priv->plane[0] + priv->width*3;
  Y = priv->Y;
  Cb = priv->Cb;
  Cr = priv->Cr;
  offset_to_next_row = 2*priv->width*3 - 8*3;
  for (i=0; i<8; i++) {

    for (j=0; j<8; j++) {

       int y, cb, cr;
       int add_r, add_g, add_b;
       int r, g , b;

       cb = *Cb++ - 128;
       cr = *Cr++ - 128;
       add_r = FIX(1.40200) * cr + ONE_HALF;
       add_g = - FIX(0.34414) * cb - FIX(0.71414) * cr + ONE_HALF;
       add_b = FIX(1.77200) * cb + ONE_HALF;

       y  = (*Y++) << SCALEBITS;
       r = (y + add_r) >> SCALEBITS;
       *p++ = clamp(r);
       g = (y + add_g) >> SCALEBITS;
       *p++ = clamp(g);
       b = (y + add_b) >> SCALEBITS;
       *p++ = clamp(b);

       y  = (Y[8-1]) << SCALEBITS;
       r = (y + add_r) >> SCALEBITS;
       *p2++ = clamp(r);
       g = (y + add_g) >> SCALEBITS;
       *p2++ = clamp(g);
       b = (y + add_b) >> SCALEBITS;
       *p2++ = clamp(b);

    }
    Y += 8;
    p += offset_to_next_row;
    p2 += offset_to_next_row;
  }

#undef SCALEBITS
#undef ONE_HALF
#undef FIX

}

/*
 *  YCrCb -> BGR24 (1x2)
 *  .---.
 *  | 1 |
 *  |---|
 *  | 2 |
 *  `---'
 */
static void YCrCB_to_BGR24_1x2(struct jdec_private *priv)
{
  const unsigned char *Y, *Cb, *Cr;
  unsigned char *p, *p2;
  int i,j;
  int offset_to_next_row;

#define SCALEBITS       10
#define ONE_HALF        (1UL << (SCALEBITS-1))
#define FIX(x)          ((int)((x) * (1UL<<SCALEBITS) + 0.5))

  p = priv->plane[0];
  p2 = priv->plane[0] + priv->width*3;
  Y = priv->Y;
  Cb = priv->Cb;
  Cr = priv->Cr;
  offset_to_next_row = 2*priv->width*3 - 8*3;
  for (i=0; i<8; i++) {

    for (j=0; j<8; j++) {

       int y, cb, cr;
       int add_r, add_g, add_b;
       int r, g , b;

       cb = *Cb++ - 128;
       cr = *Cr++ - 128;
       add_r = FIX(1.40200) * cr + ONE_HALF;
       add_g = - FIX(0.34414) * cb - FIX(0.71414) * cr + ONE_HALF;
       add_b = FIX(1.77200) * cb + ONE_HALF;

       y  = (*Y++) << SCALEBITS;
       b = (y + add_b) >> SCALEBITS;
       *p++ = clamp(b);
       g = (y + add_g) >> SCALEBITS;
       *p++ = clamp(g);
       r = (y + add_r) >> SCALEBITS;
       *p++ = clamp(r);

       y  = (Y[8-1]) << SCALEBITS;
       b = (y + add_b) >> SCALEBITS;
       *p2++ = clamp(b);
       g = (y + add_g) >> SCALEBITS;
       *p2++ = clamp(g);
       r = (y + add_r) >> SCALEBITS;
       *p2++ = clamp(r);

    }
    Y += 8;
    p += offset_to_next_row;
    p2 += offset_to_next_row;
  }

#undef SCALEBITS
#undef ONE_HALF
#undef FIX

}


/**
 *  YCrCb -> RGB24 (2x2)
 *  .-------.
 *  | 1 | 2 |
 *  |---+---|
 *  | 3 | 4 |
 *  `-------'
 */
static void YCrCB_to_RGB24_2x2(struct jdec_private *priv)
{
  const unsigned char *Y, *Cb, *Cr;
  unsigned char *p, *p2;
  int i,j;
  int offset_to_next_row;

#define SCALEBITS       10
#define ONE_HALF        (1UL << (SCALEBITS-1))
#define FIX(x)          ((int)((x) * (1UL<<SCALEBITS) + 0.5))

  p = priv->plane[0];
  p2 = priv->plane[0] + priv->width*3;
  Y = priv->Y;
  Cb = priv->Cb;
  Cr = priv->Cr;
  offset_to_next_row = (priv->width*3*2) - 16*3;
  for (i=0; i<8; i++) {

    for (j=0; j<8; j++) {

       int y, cb, cr;
       int add_r, add_g, add_b;
       int r, g , b;

       cb = *Cb++ - 128;
       cr = *Cr++ - 128;
       add_r = FIX(1.40200) * cr + ONE_HALF;
       add_g = - FIX(0.34414) * cb - FIX(0.71414) * cr + ONE_HALF;
       add_b = FIX(1.77200) * cb + ONE_HALF;

       y  = (*Y++) << SCALEBITS;
       r = (y + add_r) >> SCALEBITS;
       *p++ = clamp(r);
       g = (y + add_g) >> SCALEBITS;
       *p++ = clamp(g);
       b = (y + add_b) >> SCALEBITS;
       *p++ = clamp(b);

       y  = (*Y++) << SCALEBITS;
       r = (y + add_r) >> SCALEBITS;
       *p++ = clamp(r);
       g = (y + add_g) >> SCALEBITS;
       *p++ = clamp(g);
       b = (y + add_b) >> SCALEBITS;
       *p++ = clamp(b);

       y  = (Y[16-2]) << SCALEBITS;
       r = (y + add_r) >> SCALEBITS;
       *p2++ = clamp(r);
       g = (y + add_g) >> SCALEBITS;
       *p2++ = clamp(g);
       b = (y + add_b) >> SCALEBITS;
       *p2++ = clamp(b);

       y  = (Y[16-1]) << SCALEBITS;
       r = (y + add_r) >> SCALEBITS;
       *p2++ = clamp(r);
       g = (y + add_g) >> SCALEBITS;
       *p2++ = clamp(g);
       b = (y + add_b) >> SCALEBITS;
       *p2++ = clamp(b);
    }
    Y  += 16;
    p  += offset_to_next_row;
    p2 += offset_to_next_row;
  }

#undef SCALEBITS
#undef ONE_HALF
#undef FIX

}


/*
 *  YCrCb -> BGR24 (2x2)
 *  .-------.
 *  | 1 | 2 |
 *  |---+---|
 *  | 3 | 4 |
 *  `-------'
 */
static void YCrCB_to_BGR24_2x2(struct jdec_private *priv)
{
  const unsigned char *Y, *Cb, *Cr;
  unsigned char *p, *p2;
  int i,j;
  int offset_to_next_row;

#define SCALEBITS       10
#define ONE_HALF        (1UL << (SCALEBITS-1))
#define FIX(x)          ((int)((x) * (1UL<<SCALEBITS) + 0.5))

  p = priv->plane[0];
  p2 = priv->plane[0] + priv->width*3;
  Y = priv->Y;
  Cb = priv->Cb;
  Cr = priv->Cr;
  offset_to_next_row = (priv->width*3*2) - 16*3;
  for (i=0; i<8; i++) {

    for (j=0; j<8; j++) {

       int y, cb, cr;
       int add_r, add_g, add_b;
       int r, g , b;

       cb = *Cb++ - 128;
       cr = *Cr++ - 128;
       add_r = FIX(1.40200) * cr + ONE_HALF;
       add_g = - FIX(0.34414) * cb - FIX(0.71414) * cr + ONE_HALF;
       add_b = FIX(1.77200) * cb + ONE_HALF;

       y  = (*Y++) << SCALEBITS;
       b = (y + add_b) >> SCALEBITS;
       *p++ = clamp(b);
       g = (y + add_g) >> SCALEBITS;
       *p++ = clamp(g);
       r = (y + add_r) >> SCALEBITS;
       *p++ = clamp(r);

       y  = (*Y++) << SCALEBITS;
       b = (y + add_b) >> SCALEBITS;
       *p++ = clamp(b);
       g = (y + add_g) >> SCALEBITS;
       *p++ = clamp(g);
       r = (y + add_r) >> SCALEBITS;
       *p++ = clamp(r);

       y  = (Y[16-2]) << SCALEBITS;
       b = (y + add_b) >> SCALEBITS;
       *p2++ = clamp(b);
       g = (y + add_g) >> SCALEBITS;
       *p2++ = clamp(g);
       r = (y + add_r) >> SCALEBITS;
       *p2++ = clamp(r);

       y  = (Y[16-1]) << SCALEBITS;
       b = (y + add_b) >> SCALEBITS;
       *p2++ = clamp(b);
       g = (y + add_g) >> SCALEBITS;
       *p2++ = clamp(g);
       r = (y + add_r) >> SCALEBITS;
       *p2++ = clamp(r);
    }
    Y  += 16;
    p  += offset_to_next_row;
    p2 += offset_to_next_row;
  }

#undef SCALEBITS
#undef ONE_HALF
#undef FIX

}



/**
 *  YCrCb -> Grey (1x1)
 *  .---.
 *  | 1 |
 *  `---'
 */
static void YCrCB_to_Grey_1x1(struct jdec_private *priv)
{
  const unsigned char *y;
  unsigned char *p;
  unsigned int i;
  int offset_to_next_row;

  p = priv->plane[0];
  y = priv->Y;
  offset_to_next_row = priv->width;

  for (i=0; i<8; i++) {
     memcpy(p, y, 8);
     y+=8;
     p += offset_to_next_row;
  }
}

/**
 *  YCrCb -> Grey (2x1)
 *  .-------.
 *  | 1 | 2 |
 *  `-------'
 */
static void YCrCB_to_Grey_2x1(struct jdec_private *priv)
{
  const unsigned char *y;
  unsigned char *p;
  unsigned int i;

  p = priv->plane[0];
  y = priv->Y;

  for (i=0; i<8; i++) {
     memcpy(p, y, 16);
     y += 16;
     p += priv->width;
  }
}


/**
 *  YCrCb -> Grey (1x2)
 *  .---.
 *  | 1 |
 *  |---|
 *  | 2 |
 *  `---'
 */
static void YCrCB_to_Grey_1x2(struct jdec_private *priv)
{
  const unsigned char *y;
  unsigned char *p;
  unsigned int i;

  p = priv->plane[0];
  y = priv->Y;

  for (i=0; i<16; i++) {
     memcpy(p, y, 8);
     y += 8;
     p += priv->width;
  }
}

/**
 *  YCrCb -> Grey (2x2)
 *  .-------.
 *  | 1 | 2 |
 *  |---+---|
 *  | 3 | 4 |
 *  `-------'
 */
static void YCrCB_to_Grey_2x2(struct jdec_private *priv)
{
  const unsigned char *y;
  unsigned char *p;
  unsigned int i;

  p = priv->plane[0];
  y = priv->Y;

  for (i=0; i<16; i++) {
     memcpy(p, y, 16);
     y += 16;
     p += priv->width;
  }
}


/*
 * Decode all the 3 components for 1x1
 */
static void decode_MCU_1x1_3planes(struct jdec_private *priv)
{
  // Y
  process_Huffman_data_unit(priv, cY);
  IDCT(&priv->component_infos[cY], priv->Y, 8);

  // Cb
  process_Huffman_data_unit(priv, cCb);
  IDCT(&priv->component_infos[cCb], priv->Cb, 8);

  // Cr
  process_Huffman_data_unit(priv, cCr);
  IDCT(&priv->component_infos[cCr], priv->Cr, 8);
}

/*
 * Decode a 1x1 directly in 1 color
 */
static void decode_MCU_1x1_1plane(struct jdec_private *priv)
{
  // Y
  process_Huffman_data_unit(priv, cY);
  IDCT(&priv->component_infos[cY], priv->Y, 8);

  // Cb
  process_Huffman_data_unit(priv, cCb);
  IDCT(&priv->component_infos[cCb], priv->Cb, 8);

  // Cr
  process_Huffman_data_unit(priv, cCr);
  IDCT(&priv->component_infos[cCr], priv->Cr, 8);
}


/*
 * Decode a 2x1
 *  .-------.
 *  | 1 | 2 |
 *  `-------'
 */
static void decode_MCU_2x1_3planes(struct jdec_private *priv)
{
  // Y
  process_Huffman_data_unit(priv, cY);
  IDCT(&priv->component_infos[cY], priv->Y, 16);
  process_Huffman_data_unit(priv, cY);
  IDCT(&priv->component_infos[cY], priv->Y+8, 16);

  // Cb
  process_Huffman_data_unit(priv, cCb);
  IDCT(&priv->component_infos[cCb], priv->Cb, 8);

  // Cr
  process_Huffman_data_unit(priv, cCr);
  IDCT(&priv->component_infos[cCr], priv->Cr, 8);
}

static void pixart_decode_MCU_2x1_3planes(struct jdec_private *priv)
{
  unsigned char marker;

  pixart_look_nbits(priv->reservoir, priv->nbits_in_reservoir, priv->stream,
                8, marker);
  /* I think the marker indicates which quantization table to use, iow
     a Pixart JPEG may have a different quantization table per MCU, most
     MCU's have 0x44 as marker for which our special Pixart quantization
     tables are correct. Unfortunately with a 7302 some blocks also have 0x48,
     and sometimes even other values. As 0x48 is quite common too, we really
     need to find out the correct table for that, as currently the blocks
     with a 0x48 marker look wrong. During normal operation the marker stays
     within the range below, if it gets out of this range we're most likely
     decoding garbage */
  if (marker < 0x20 || marker > 0x7f) {
    snprintf(priv->error_string, sizeof(priv->error_string),
      "Pixart JPEG error: invalid MCU marker: 0x%02x\n",
      (unsigned int)marker);
    longjmp(priv->jump_state, -EIO);
  }
  skip_nbits(priv->reservoir, priv->nbits_in_reservoir, priv->stream, 8);

  // Y
  pixart_process_Huffman_data_unit(priv, cY);
  IDCT(&priv->component_infos[cY], priv->Y, 16);
  pixart_process_Huffman_data_unit(priv, cY);
  IDCT(&priv->component_infos[cY], priv->Y+8, 16);

  // Cb
  pixart_process_Huffman_data_unit(priv, cCb);
  IDCT(&priv->component_infos[cCb], priv->Cb, 8);

  // Cr
  pixart_process_Huffman_data_unit(priv, cCr);
  IDCT(&priv->component_infos[cCr], priv->Cr, 8);
}

/*
 * Decode a 2x1
 *  .-------.
 *  | 1 | 2 |
 *  `-------'
 */
static void decode_MCU_2x1_1plane(struct jdec_private *priv)
{
  // Y
  process_Huffman_data_unit(priv, cY);
  IDCT(&priv->component_infos[cY], priv->Y, 16);
  process_Huffman_data_unit(priv, cY);
  IDCT(&priv->component_infos[cY], priv->Y+8, 16);

  // Cb
  process_Huffman_data_unit(priv, cCb);

  // Cr
  process_Huffman_data_unit(priv, cCr);
}


/*
 * Decode a 2x2
 *  .-------.
 *  | 1 | 2 |
 *  |---+---|
 *  | 3 | 4 |
 *  `-------'
 */
static void decode_MCU_2x2_3planes(struct jdec_private *priv)
{
  // Y
  process_Huffman_data_unit(priv, cY);
  IDCT(&priv->component_infos[cY], priv->Y, 16);
  process_Huffman_data_unit(priv, cY);
  IDCT(&priv->component_infos[cY], priv->Y+8, 16);
  process_Huffman_data_unit(priv, cY);
  IDCT(&priv->component_infos[cY], priv->Y+64*2, 16);
  process_Huffman_data_unit(priv, cY);
  IDCT(&priv->component_infos[cY], priv->Y+64*2+8, 16);

  // Cb
  process_Huffman_data_unit(priv, cCb);
  IDCT(&priv->component_infos[cCb], priv->Cb, 8);

  // Cr
  process_Huffman_data_unit(priv, cCr);
  IDCT(&priv->component_infos[cCr], priv->Cr, 8);
}

/*
 * Decode a 2x2 directly in GREY format (8bits)
 *  .-------.
 *  | 1 | 2 |
 *  |---+---|
 *  | 3 | 4 |
 *  `-------'
 */
static void decode_MCU_2x2_1plane(struct jdec_private *priv)
{
  // Y
  process_Huffman_data_unit(priv, cY);
  IDCT(&priv->component_infos[cY], priv->Y, 16);
  process_Huffman_data_unit(priv, cY);
  IDCT(&priv->component_infos[cY], priv->Y+8, 16);
  process_Huffman_data_unit(priv, cY);
  IDCT(&priv->component_infos[cY], priv->Y+64*2, 16);
  process_Huffman_data_unit(priv, cY);
  IDCT(&priv->component_infos[cY], priv->Y+64*2+8, 16);

  // Cb
  process_Huffman_data_unit(priv, cCb);

  // Cr
  process_Huffman_data_unit(priv, cCr);
}

/*
 * Decode a 1x2 mcu
 *  .---.
 *  | 1 |
 *  |---|
 *  | 2 |
 *  `---'
 */
static void decode_MCU_1x2_3planes(struct jdec_private *priv)
{
  // Y
  process_Huffman_data_unit(priv, cY);
  IDCT(&priv->component_infos[cY], priv->Y, 8);
  process_Huffman_data_unit(priv, cY);
  IDCT(&priv->component_infos[cY], priv->Y+64, 8);

  // Cb
  process_Huffman_data_unit(priv, cCb);
  IDCT(&priv->component_infos[cCb], priv->Cb, 8);

  // Cr
  process_Huffman_data_unit(priv, cCr);
  IDCT(&priv->component_infos[cCr], priv->Cr, 8);
}

/*
 * Decode a 1x2 mcu
 *  .---.
 *  | 1 |
 *  |---|
 *  | 2 |
 *  `---'
 */
static void decode_MCU_1x2_1plane(struct jdec_private *priv)
{
  // Y
  process_Huffman_data_unit(priv, cY);
  IDCT(&priv->component_infos[cY], priv->Y, 8);
  process_Huffman_data_unit(priv, cY);
  IDCT(&priv->component_infos[cY], priv->Y+64, 8);

  // Cb
  process_Huffman_data_unit(priv, cCb);

  // Cr
  process_Huffman_data_unit(priv, cCr);
}

static void print_SOF(const unsigned char *stream)
{
  int width, height, nr_components, precision;
#if DEBUG
  const char *nr_components_to_string[] = {
     "????",
     "Grayscale",
     "????",
     "YCbCr",
     "CYMK"
  };
#endif

  precision = stream[2];
  height = be16_to_cpu(stream+3);
  width  = be16_to_cpu(stream+5);
  nr_components = stream[7];

  trace("> SOF marker\n");
  trace("Size:%dx%d nr_components:%d (%s)  precision:%d\n",
      width, height,
      nr_components, nr_components_to_string[nr_components],
      precision);
}

/*******************************************************************************
 *
 * JPEG/JFIF Parsing functions
 *
 * Note: only a small subset of the jpeg file format is supported. No markers,
 * nor progressive stream is supported.
 *
 ******************************************************************************/

static void build_quantization_table(float *qtable, const unsigned char *ref_table)
{
  /* Taken from libjpeg. Copyright Independent JPEG Group's LLM idct.
   * For float AA&N IDCT method, divisors are equal to quantization
   * coefficients scaled by scalefactor[row]*scalefactor[col], where
   *   scalefactor[0] = 1
   *   scalefactor[k] = cos(k*PI/16) * sqrt(2)    for k=1..7
   * We apply a further scale factor of 8.
   * What's actually stored is 1/divisor so that the inner loop can
   * use a multiplication rather than a division.
   */
  int i, j;
  static const double aanscalefactor[8] = {
     1.0, 1.387039845, 1.306562965, 1.175875602,
     1.0, 0.785694958, 0.541196100, 0.275899379
  };
  const unsigned char *zz = zigzag;

  for (i=0; i<8; i++) {
     for (j=0; j<8; j++) {
       *qtable++ = ref_table[*zz++] * aanscalefactor[i] * aanscalefactor[j];
     }
   }

}

static int parse_DQT(struct jdec_private *priv, const unsigned char *stream)
{
  int qi;
  float *table;
  const unsigned char *dqt_block_end;

  trace("> DQT marker\n");
  dqt_block_end = stream + be16_to_cpu(stream);
  stream += 2;    /* Skip length */

  while (stream < dqt_block_end)
   {
     qi = *stream++;
#if SANITY_CHECK
     if (qi>>4)
       error("16 bits quantization table is not supported\n");
     if (qi >= COMPONENTS)
       error("No more than %d quantization tables supported (got %d)\n",
       COMPONENTS, qi + 1);
#endif
     table = priv->Q_tables[qi];
     build_quantization_table(table, stream);
     stream += 64;
   }
  trace("< DQT marker\n");
  return 0;
}

static int parse_SOF(struct jdec_private *priv, const unsigned char *stream)
{
  int i, width, height, nr_components, cid, sampling_factor;
  int Q_table;
  struct component *c;

  trace("> SOF marker\n");
  print_SOF(stream);

  height = be16_to_cpu(stream+3);
  width  = be16_to_cpu(stream+5);
  nr_components = stream[7];
#if SANITY_CHECK
  if (stream[2] != 8)
    error("Precision other than 8 is not supported\n");
  if (width>JPEG_MAX_WIDTH || height>JPEG_MAX_HEIGHT)
    error("Width and Height (%dx%d) seems suspicious\n", width, height);
  if (nr_components != 3)
    error("We only support YUV images\n");
  if (height%8)
    error("Height need to be a multiple of 8 (current height is %d)\n", height);
  if (width%16)
    error("Width need to be a multiple of 16 (current Width is %d)\n", width);
#endif
  stream += 8;
  for (i=0; i<nr_components; i++) {
     cid = *stream++;
     sampling_factor = *stream++;
     Q_table = *stream++;
     c = &priv->component_infos[i];
#if SANITY_CHECK
     c->cid = cid;
#endif
     c->Vfactor = sampling_factor&0xf;
     c->Hfactor = sampling_factor>>4;
     c->Q_table = priv->Q_tables[Q_table];
     trace("Component:%d  factor:%dx%d  Quantization table:%d\n",
       cid, c->Hfactor, c->Hfactor, Q_table );

  }
  priv->width = width;
  priv->height = height;

  trace("< SOF marker\n");

  return 0;
}

static int parse_SOS(struct jdec_private *priv, const unsigned char *stream)
{
  unsigned int i, cid, table;
  unsigned int nr_components = stream[2];

  trace("> SOS marker\n");

#if SANITY_CHECK
  if (nr_components != 3)
    error("We only support YCbCr image\n");
#endif

  stream += 3;
  for (i=0;i<nr_components;i++) {
     cid = *stream++;
     table = *stream++;
#if SANITY_CHECK
     if ((table&0xf) >= HUFFMAN_TABLES)
      error("We do not support more than %d AC Huffman table\n",
        HUFFMAN_TABLES);
     if ((table>>4) >= HUFFMAN_TABLES)
      error("We do not support more than %d DC Huffman table\n",
        HUFFMAN_TABLES);
     if (cid != priv->component_infos[i].cid)
      error("SOS cid order (%u:%u) isn't compatible with the SOF marker (%u:%u)\n",
            i, cid, i, priv->component_infos[i].cid);
     trace("ComponentId:%u  tableAC:%d tableDC:%d\n", cid, table&0xf, table>>4);
#endif
     priv->component_infos[i].AC_table = &priv->HTAC[table&0xf];
     priv->component_infos[i].DC_table = &priv->HTDC[table>>4];
  }
  priv->stream = stream+3;

  /* ITU-T T.81 (9/92) chapter E.1.3 clearly states that RSTm is to be set to 0 at the beginning of each scan */
  priv->last_rst_marker_seen = 0;

  trace("< SOS marker\n");

  return 0;
}

static int parse_DHT(struct jdec_private *priv, const unsigned char *stream)
{
  unsigned int count, i;
  unsigned char huff_bits[17];
  int length, index;

  length = be16_to_cpu(stream) - 2;
  stream += 2;    /* Skip length */

  trace("> DHT marker (length=%d)\n", length);

  while (length>0) {
     index = *stream++;

     /* We need to calculate the number of bytes 'vals' will takes */
     huff_bits[0] = 0;
     count = 0;
     for (i=1; i<17; i++) {
      huff_bits[i] = *stream++;
      count += huff_bits[i];
     }
#if SANITY_CHECK
     if (count > 1024)
       error("No more than 1024 bytes is allowed to describe a huffman table\n");
     if ( (index &0xf) >= HUFFMAN_TABLES)
       error("No mode than %d Huffman tables is supported\n", HUFFMAN_TABLES);
     trace("Huffman table %s n%d\n", (index&0xf0)?"AC":"DC", index&0xf);
     trace("Length of the table: %d\n", count);
#endif

     if (index & 0xf0 ) {
       if (build_huffman_table(priv, huff_bits, stream, &priv->HTAC[index&0xf]))
       return -1;
     } else {
       if (build_huffman_table(priv, huff_bits, stream, &priv->HTDC[index&0xf]))
       return -1;
     }

     length -= 1;
     length -= 16;
     length -= count;
     stream += count;
  }
  trace("< DHT marker\n");
  return 0;
}

static int parse_DRI(struct jdec_private *priv, const unsigned char *stream)
{
  unsigned int length;

  trace("> DRI marker\n");

  length = be16_to_cpu(stream);

#if SANITY_CHECK
  if (length != 4)
    error("Length of DRI marker need to be 4\n");
#endif

  priv->restart_interval = be16_to_cpu(stream+2);

#if DEBUG
  trace("Restart interval = %d\n", priv->restart_interval);
#endif

  trace("< DRI marker\n");

  return 0;
}



static void resync(struct jdec_private *priv)
{
  int i;

  /* Init DC coefficients */
  for (i=0; i<COMPONENTS; i++)
     priv->component_infos[i].previous_DC = 0;

  priv->reservoir = 0;
  priv->nbits_in_reservoir = 0;
  if (priv->restart_interval > 0)
    priv->restarts_to_go = priv->restart_interval;
  else
    priv->restarts_to_go = -1;
}

static int find_next_rst_marker(struct jdec_private *priv)
{
  int rst_marker_found = 0;
  int marker;
  const unsigned char *stream = priv->stream;

  /* Parse marker */
  while (!rst_marker_found)
   {
     while (*stream++ != 0xff)
      {
      if (stream >= priv->stream_end)
        error("EOF while search for a RST marker.\n");
      }
     /* Skip any padding ff byte (this is normal) */
     while (*stream == 0xff)
       stream++;

     marker = *stream++;
     if ((RST+priv->last_rst_marker_seen) == marker)
       rst_marker_found = 1;
     else if (marker >= RST && marker <= RST7)
       error("Wrong Reset marker found, abording\n");
     else if (marker == EOI)
       return 0;
   }

  priv->stream = stream;
  priv->last_rst_marker_seen++;
  priv->last_rst_marker_seen &= 7;

  return 0;
}

static int parse_JFIF(struct jdec_private *priv, const unsigned char *stream)
{
  int chuck_len;
  int marker;
  int sof_marker_found = 0;
  int dqt_marker_found = 0;
  int sos_marker_found = 0;
  int dht_marker_found = 0;
  const unsigned char *next_chunck;

  /* Parse marker */
  while (!sos_marker_found)
   {
     if (*stream++ != 0xff)
       goto bogus_jpeg_format;
     /* Skip any padding ff byte (this is normal) */
     while (*stream == 0xff)
       stream++;

     marker = *stream++;
     chuck_len = be16_to_cpu(stream);
     next_chunck = stream + chuck_len;
     switch (marker)
      {
       case SOF:
       if (parse_SOF(priv, stream) < 0)
         return -1;
       sof_marker_found = 1;
       break;
       case DQT:
       if (parse_DQT(priv, stream) < 0)
         return -1;
       dqt_marker_found = 1;
       break;
       case SOS:
       if (parse_SOS(priv, stream) < 0)
         return -1;
       sos_marker_found = 1;
       break;
       case DHT:
       if (parse_DHT(priv, stream) < 0)
         return -1;
       dht_marker_found = 1;
       break;
       case DRI:
       if (parse_DRI(priv, stream) < 0)
         return -1;
       break;
       default:
       trace("> Unknown marker %2.2x\n", marker);
       break;
      }

     stream = next_chunck;
   }

  if ( !sof_marker_found ||
      (!dqt_marker_found && !(priv->flags & TINYJPEG_FLAGS_PIXART_JPEG)))
    goto bogus_jpeg_format;

  if (priv->flags & TINYJPEG_FLAGS_PIXART_JPEG) {
    if (!priv->default_huffman_table_initialized) {
      build_quantization_table(priv->Q_tables[0], pixart_quantization[0]);
      build_quantization_table(priv->Q_tables[1], pixart_quantization[1]);
    }

    /* Pixart JPEG data starts with one unknown / unused byte */
    priv->stream++;
  }

  if (!dht_marker_found) {
    trace("No Huffman table loaded, using the default one\n");
    if (build_default_huffman_tables(priv))
      return -1;
  }

#ifdef SANITY_CHECK
  if (   (priv->component_infos[cY].Hfactor < priv->component_infos[cCb].Hfactor)
      || (priv->component_infos[cY].Hfactor < priv->component_infos[cCr].Hfactor))
    error("Horizontal sampling factor for Y should be greater than horitontal sampling factor for Cb or Cr\n");
  if (   (priv->component_infos[cY].Vfactor < priv->component_infos[cCb].Vfactor)
      || (priv->component_infos[cY].Vfactor < priv->component_infos[cCr].Vfactor))
    error("Vertical sampling factor for Y should be greater than vertical sampling factor for Cb or Cr\n");
  if (   (priv->component_infos[cCb].Hfactor!=1)
      || (priv->component_infos[cCr].Hfactor!=1)
      || (priv->component_infos[cCb].Vfactor!=1)
      || (priv->component_infos[cCr].Vfactor!=1))
    error("Sampling other than 1x1 for Cr and Cb is not supported\n");
#endif

  return 0;
bogus_jpeg_format:
  error("Bogus jpeg format\n");
  return -1;
}

/*******************************************************************************
 *
 * Functions exported of the library.
 *
 * Note: Some applications can access directly to internal pointer of the
 * structure. It's is not recommended, but if you have many images to
 * uncompress with the same parameters, some functions can be called to speedup
 * the decoding.
 *
 ******************************************************************************/

/**
 * Allocate a new tinyjpeg decoder object.
 *
 * Before calling any other functions, an object need to be called.
 */
struct jdec_private *tinyjpeg_init(void)
{
  struct jdec_private *priv;

  priv = (struct jdec_private *)calloc(1, sizeof(struct jdec_private));
  if (priv == NULL)
    return NULL;
  return priv;
}

/**
 * Free a tinyjpeg object.
 *
 * No others function can be called after this one.
 */
void tinyjpeg_free(struct jdec_private *priv)
{
  int i;
  for (i=0; i<COMPONENTS; i++) {
     if (priv->components[i])
       free(priv->components[i]);
     priv->components[i] = NULL;
  }
  free(priv);
}

/**
 * Initialize the tinyjpeg object and prepare the decoding of the stream.
 *
 * Check if the jpeg can be decoded with this jpeg decoder.
 * Fill some table used for preprocessing.
 */
int tinyjpeg_parse_header(struct jdec_private *priv, const unsigned char *buf, unsigned int size)
{
  int ret;

  /* Identify the file */
  if ((buf[0] != 0xFF) || (buf[1] != SOI))
    error("Not a JPG file ?\n");

  priv->stream_begin = buf+2;
  priv->stream_length = size-2;
  priv->stream_end = priv->stream_begin + priv->stream_length;

  ret = parse_JFIF(priv, priv->stream_begin);

  return ret;
}

static const decode_MCU_fct decode_mcu_3comp_table[4] = {
   decode_MCU_1x1_3planes,
   decode_MCU_1x2_3planes,
   decode_MCU_2x1_3planes,
   decode_MCU_2x2_3planes,
};

static const decode_MCU_fct pixart_decode_mcu_3comp_table[4] = {
   NULL,
   NULL,
   pixart_decode_MCU_2x1_3planes,
   NULL,
};

static const decode_MCU_fct decode_mcu_1comp_table[4] = {
   decode_MCU_1x1_1plane,
   decode_MCU_1x2_1plane,
   decode_MCU_2x1_1plane,
   decode_MCU_2x2_1plane,
};

static const convert_colorspace_fct convert_colorspace_yuv420p[4] = {
   YCrCB_to_YUV420P_1x1,
   YCrCB_to_YUV420P_1x2,
   YCrCB_to_YUV420P_2x1,
   YCrCB_to_YUV420P_2x2,
};

static const convert_colorspace_fct convert_colorspace_rgb24[4] = {
   YCrCB_to_RGB24_1x1,
   YCrCB_to_RGB24_1x2,
   YCrCB_to_RGB24_2x1,
   YCrCB_to_RGB24_2x2,
};

static const convert_colorspace_fct convert_colorspace_bgr24[4] = {
   YCrCB_to_BGR24_1x1,
   YCrCB_to_BGR24_1x2,
   YCrCB_to_BGR24_2x1,
   YCrCB_to_BGR24_2x2,
};

static const convert_colorspace_fct convert_colorspace_grey[4] = {
   YCrCB_to_Grey_1x1,
   YCrCB_to_Grey_1x2,
   YCrCB_to_Grey_2x1,
   YCrCB_to_Grey_2x2,
};

/**
 * Decode and convert the jpeg image into @pixfmt@ image
 *
 * Note: components will be automaticaly allocated if no memory is attached.
 */
int tinyjpeg_decode(struct jdec_private *priv, int pixfmt)
{
  unsigned int x, y, xstride_by_mcu, ystride_by_mcu;
  unsigned int bytes_per_blocklines[3], bytes_per_mcu[3];
  decode_MCU_fct decode_MCU;
  const decode_MCU_fct *decode_mcu_table;
  const convert_colorspace_fct *colorspace_array_conv;
  convert_colorspace_fct convert_to_pixfmt;

  if (setjmp(priv->jump_state))
    return -1;

  /* To keep gcc happy initialize some array */
  bytes_per_mcu[1] = 0;
  bytes_per_mcu[2] = 0;
  bytes_per_blocklines[1] = 0;
  bytes_per_blocklines[2] = 0;

  decode_mcu_table = decode_mcu_3comp_table;
  if (priv->flags & TINYJPEG_FLAGS_PIXART_JPEG)
    decode_mcu_table = pixart_decode_mcu_3comp_table;

  switch (pixfmt) {
     case TINYJPEG_FMT_YUV420P:
       colorspace_array_conv = convert_colorspace_yuv420p;
       if (priv->components[0] == NULL)
       priv->components[0] = (uint8_t *)malloc(priv->width * priv->height);
       if (priv->components[1] == NULL)
       priv->components[1] = (uint8_t *)malloc(priv->width * priv->height/4);
       if (priv->components[2] == NULL)
       priv->components[2] = (uint8_t *)malloc(priv->width * priv->height/4);
       bytes_per_blocklines[0] = priv->width;
       bytes_per_blocklines[1] = priv->width/4;
       bytes_per_blocklines[2] = priv->width/4;
       bytes_per_mcu[0] = 8;
       bytes_per_mcu[1] = 4;
       bytes_per_mcu[2] = 4;
       break;

     case TINYJPEG_FMT_RGB24:
       colorspace_array_conv = convert_colorspace_rgb24;
       if (priv->components[0] == NULL)
       priv->components[0] = (uint8_t *)malloc(priv->width * priv->height * 3);
       bytes_per_blocklines[0] = priv->width * 3;
       bytes_per_mcu[0] = 3*8;
       break;

     case TINYJPEG_FMT_BGR24:
       colorspace_array_conv = convert_colorspace_bgr24;
       if (priv->components[0] == NULL)
       priv->components[0] = (uint8_t *)malloc(priv->width * priv->height * 3);
       bytes_per_blocklines[0] = priv->width * 3;
       bytes_per_mcu[0] = 3*8;
       break;

     case TINYJPEG_FMT_GREY:
       decode_mcu_table = decode_mcu_1comp_table;
       if (priv->flags & TINYJPEG_FLAGS_PIXART_JPEG)
       error("Greyscale output not support for PIXART JPEG's\n");
       colorspace_array_conv = convert_colorspace_grey;
       if (priv->components[0] == NULL)
       priv->components[0] = (uint8_t *)malloc(priv->width * priv->height);
       bytes_per_blocklines[0] = priv->width;
       bytes_per_mcu[0] = 8;
       break;

     default:
       error("Bad pixel format\n");
  }

  xstride_by_mcu = ystride_by_mcu = 8;
  if ((priv->component_infos[cY].Hfactor | priv->component_infos[cY].Vfactor) == 1) {
     decode_MCU = decode_mcu_table[0];
     convert_to_pixfmt = colorspace_array_conv[0];
     trace("Use decode 1x1 sampling\n");
  } else if (priv->component_infos[cY].Hfactor == 1) {
     decode_MCU = decode_mcu_table[1];
     convert_to_pixfmt = colorspace_array_conv[1];
     ystride_by_mcu = 16;
     trace("Use decode 1x2 sampling (not supported)\n");
  } else if (priv->component_infos[cY].Vfactor == 2) {
     decode_MCU = decode_mcu_table[3];
     convert_to_pixfmt = colorspace_array_conv[3];
     xstride_by_mcu = 16;
     ystride_by_mcu = 16;
     trace("Use decode 2x2 sampling\n");
  } else {
     decode_MCU = decode_mcu_table[2];
     convert_to_pixfmt = colorspace_array_conv[2];
     xstride_by_mcu = 16;
     trace("Use decode 2x1 sampling\n");
  }

  if (decode_MCU == NULL)
    error("no decode MCU function for this JPEG format (PIXART?)\n");

  resync(priv);

  /* Don't forget to that block can be either 8 or 16 lines */
  bytes_per_blocklines[0] *= ystride_by_mcu;
  bytes_per_blocklines[1] *= ystride_by_mcu;
  bytes_per_blocklines[2] *= ystride_by_mcu;

  bytes_per_mcu[0] *= xstride_by_mcu/8;
  bytes_per_mcu[1] *= xstride_by_mcu/8;
  bytes_per_mcu[2] *= xstride_by_mcu/8;

  /* Just the decode the image by macroblock (size is 8x8, 8x16, or 16x16) */
  for (y=0; y < priv->height/ystride_by_mcu; y++)
   {
     //trace("Decoding row %d\n", y);
     priv->plane[0] = priv->components[0] + (y * bytes_per_blocklines[0]);
     priv->plane[1] = priv->components[1] + (y * bytes_per_blocklines[1]);
     priv->plane[2] = priv->components[2] + (y * bytes_per_blocklines[2]);
     for (x=0; x < priv->width; x+=xstride_by_mcu)
      {
      decode_MCU(priv);
      convert_to_pixfmt(priv);
      priv->plane[0] += bytes_per_mcu[0];
      priv->plane[1] += bytes_per_mcu[1];
      priv->plane[2] += bytes_per_mcu[2];
      if (priv->restarts_to_go>0)
       {
         priv->restarts_to_go--;
         if (priv->restarts_to_go == 0)
          {
            priv->stream -= (priv->nbits_in_reservoir/8);
            resync(priv);
            if (find_next_rst_marker(priv) < 0)
            return -1;
          }
       }
      }
   }

  if (priv->flags & TINYJPEG_FLAGS_PIXART_JPEG) {
    /* Additional sanity check for funky Pixart format */
    if ((priv->stream_end - priv->stream) > 5)
      error("Pixart JPEG error, stream does not end with EOF marker\n");
  }

  return 0;
}

const char *tinyjpeg_get_errorstring(struct jdec_private *priv)
{
  return priv->error_string;
}

void tinyjpeg_get_size(struct jdec_private *priv, unsigned int *width, unsigned int *height)
{
  *width = priv->width;
  *height = priv->height;
}

int tinyjpeg_get_components(struct jdec_private *priv, unsigned char **components)
{
  int i;
  for (i=0; priv->components[i] && i<COMPONENTS; i++)
    components[i] = priv->components[i];
  return 0;
}

int tinyjpeg_set_components(struct jdec_private *priv, unsigned char **components, unsigned int ncomponents)
{
  unsigned int i;
  if (ncomponents > COMPONENTS)
    ncomponents = COMPONENTS;
  for (i=0; i<ncomponents; i++)
    priv->components[i] = components[i];
  return 0;
}

int tinyjpeg_set_flags(struct jdec_private *priv, int flags)
{
  int oldflags = priv->flags;
  priv->flags = flags;
  return oldflags;
}


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