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 */
decode_MCU_1x1_1plane(struct jdec_private * priv)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 */
decode_MCU_2x1_1plane(struct jdec_private * priv)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 */
decode_MCU_2x2_1plane(struct jdec_private * priv)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 */
decode_MCU_1x2_1plane(struct jdec_private * priv)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 };
139