com32/lib/jpeg/decode1.c

   1 /*
   2  * Small jpeg decoder library
   3  *
   4  * Copyright (c) 2006, Luc Saillard <luc@saillard.org>
   5  * All rights reserved.
   6  * Redistribution and use in source and binary forms, with or without
   7  * modification, are permitted provided that the following conditions are met:
   8  *
   9  * - Redistributions of source code must retain the above copyright notice,
  10  *  this list of conditions and the following disclaimer.
  11  *
  12  * - Redistributions in binary form must reproduce the above copyright notice,
  13  *  this list of conditions and the following disclaimer in the documentation
  14  *  and/or other materials provided with the distribution.
  15  *
  16  * - Neither the name of the author nor the names of its contributors may be
  17  *  used to endorse or promote products derived from this software without
  18  *  specific prior written permission.
  19  *
  20  * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
  21  * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
  22  * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
  23  * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE
  24  * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
  25  * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF
  26  * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
  27  * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN
  28  * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE)
  29  * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
  30  * POSSIBILITY OF SUCH DAMAGE.
  31  *
  32  */
  33
  34 #include <stdio.h>
  35 #include <stdlib.h>
  36 #include <string.h>
  37 #include <stdint.h>
  38
  39 #include "tinyjpeg.h"
  40 #include "tinyjpeg-internal.h"
  41
  42 /*
  43  * Decode a 1x1 directly in 1 color
  44  */
  45 static void decode_MCU_1x1_1plane(struct jdec_private *priv)
  46 {
  47   // Y
  48   tinyjpeg_process_Huffman_data_unit(priv, cY);
  49   IDCT(&priv->component_infos[cY], priv->Y, 8);
  50
  51   // Cb
  52   tinyjpeg_process_Huffman_data_unit(priv, cCb);
  53   IDCT(&priv->component_infos[cCb], priv->Cb, 8);
  54
  55   // Cr
  56   tinyjpeg_process_Huffman_data_unit(priv, cCr);
  57   IDCT(&priv->component_infos[cCr], priv->Cr, 8);
  58 }
  59
  60
  61 /*
  62  * Decode a 2x1
  63  *  .-------.
  64  *  | 1 | 2 |
  65  *  `-------'
  66  */
  67 static void decode_MCU_2x1_1plane(struct jdec_private *priv)
  68 {
  69   // Y
  70   tinyjpeg_process_Huffman_data_unit(priv, cY);
  71   IDCT(&priv->component_infos[cY], priv->Y, 16);
  72   tinyjpeg_process_Huffman_data_unit(priv, cY);
  73   IDCT(&priv->component_infos[cY], priv->Y+8, 16);
  74
  75   // Cb
  76   tinyjpeg_process_Huffman_data_unit(priv, cCb);
  77
  78   // Cr
  79   tinyjpeg_process_Huffman_data_unit(priv, cCr);
  80 }
  81
  82
  83 /*
  84  * Decode a 2x2 directly in GREY format (8bits)
  85  *  .-------.
  86  *  | 1 | 2 |
  87  *  |---+---|
  88  *  | 3 | 4 |
  89  *  `-------'
  90  */
  91 static void decode_MCU_2x2_1plane(struct jdec_private *priv)
  92 {
  93   // Y
  94   tinyjpeg_process_Huffman_data_unit(priv, cY);
  95   IDCT(&priv->component_infos[cY], priv->Y, 16);
  96   tinyjpeg_process_Huffman_data_unit(priv, cY);
  97   IDCT(&priv->component_infos[cY], priv->Y+8, 16);
  98   tinyjpeg_process_Huffman_data_unit(priv, cY);
  99   IDCT(&priv->component_infos[cY], priv->Y+64*2, 16);
 100   tinyjpeg_process_Huffman_data_unit(priv, cY);
 101   IDCT(&priv->component_infos[cY], priv->Y+64*2+8, 16);
 102
 103   // Cb
 104   tinyjpeg_process_Huffman_data_unit(priv, cCb);
 105
 106   // Cr
 107   tinyjpeg_process_Huffman_data_unit(priv, cCr);
 108 }
 109
 110 /*
 111  * Decode a 1x2 mcu
 112  *  .---.
 113  *  | 1 |
 114  *  |---|
 115  *  | 2 |
 116  *  `---'
 117  */
 118 static void decode_MCU_1x2_1plane(struct jdec_private *priv)
 119 {
 120   // Y
 121   tinyjpeg_process_Huffman_data_unit(priv, cY);
 122   IDCT(&priv->component_infos[cY], priv->Y, 8);
 123   tinyjpeg_process_Huffman_data_unit(priv, cY);
 124   IDCT(&priv->component_infos[cY], priv->Y+64, 8);
 125
 126   // Cb
 127   tinyjpeg_process_Huffman_data_unit(priv, cCb);
 128
 129   // Cr
 130   tinyjpeg_process_Huffman_data_unit(priv, cCr);
 131 }
 132
 133 const decode_MCU_fct tinyjpeg_decode_mcu_1comp_table[4] = {
 134    decode_MCU_1x1_1plane,
 135    decode_MCU_1x2_1plane,
 136    decode_MCU_2x1_1plane,
 137    decode_MCU_2x2_1plane,
 138 };