1 | /* |
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2 | * jcmarker.c |
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3 | * |
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4 | * Copyright (C) 1991-1998, Thomas G. Lane. |
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5 | * Modified 2003-2010 by Guido Vollbeding. |
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6 | * This file is part of the Independent JPEG Group's software. |
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7 | * For conditions of distribution and use, see the accompanying README file. |
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8 | * |
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9 | * This file contains routines to write JPEG datastream markers. |
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10 | */ |
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11 | |
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12 | #define JPEG_INTERNALS |
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13 | #include "jinclude.h" |
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14 | #include "jpeglib.h" |
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15 | |
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16 | |
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17 | typedef enum { /* JPEG marker codes */ |
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18 | M_SOF0 = 0xc0, |
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19 | M_SOF1 = 0xc1, |
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20 | M_SOF2 = 0xc2, |
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21 | M_SOF3 = 0xc3, |
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22 | |
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23 | M_SOF5 = 0xc5, |
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24 | M_SOF6 = 0xc6, |
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25 | M_SOF7 = 0xc7, |
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26 | |
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27 | M_JPG = 0xc8, |
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28 | M_SOF9 = 0xc9, |
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29 | M_SOF10 = 0xca, |
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30 | M_SOF11 = 0xcb, |
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31 | |
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32 | M_SOF13 = 0xcd, |
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33 | M_SOF14 = 0xce, |
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34 | M_SOF15 = 0xcf, |
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35 | |
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36 | M_DHT = 0xc4, |
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37 | |
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38 | M_DAC = 0xcc, |
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39 | |
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40 | M_RST0 = 0xd0, |
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41 | M_RST1 = 0xd1, |
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42 | M_RST2 = 0xd2, |
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43 | M_RST3 = 0xd3, |
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44 | M_RST4 = 0xd4, |
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45 | M_RST5 = 0xd5, |
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46 | M_RST6 = 0xd6, |
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47 | M_RST7 = 0xd7, |
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48 | |
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49 | M_SOI = 0xd8, |
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50 | M_EOI = 0xd9, |
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51 | M_SOS = 0xda, |
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52 | M_DQT = 0xdb, |
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53 | M_DNL = 0xdc, |
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54 | M_DRI = 0xdd, |
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55 | M_DHP = 0xde, |
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56 | M_EXP = 0xdf, |
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57 | |
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58 | M_APP0 = 0xe0, |
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59 | M_APP1 = 0xe1, |
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60 | M_APP2 = 0xe2, |
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61 | M_APP3 = 0xe3, |
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62 | M_APP4 = 0xe4, |
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63 | M_APP5 = 0xe5, |
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64 | M_APP6 = 0xe6, |
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65 | M_APP7 = 0xe7, |
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66 | M_APP8 = 0xe8, |
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67 | M_APP9 = 0xe9, |
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68 | M_APP10 = 0xea, |
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69 | M_APP11 = 0xeb, |
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70 | M_APP12 = 0xec, |
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71 | M_APP13 = 0xed, |
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72 | M_APP14 = 0xee, |
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73 | M_APP15 = 0xef, |
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74 | |
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75 | M_JPG0 = 0xf0, |
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76 | M_JPG13 = 0xfd, |
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77 | M_COM = 0xfe, |
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78 | |
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79 | M_TEM = 0x01, |
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80 | |
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81 | M_ERROR = 0x100 |
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82 | } JPEG_MARKER; |
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83 | |
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84 | |
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85 | /* Private state */ |
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86 | |
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87 | typedef struct { |
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88 | struct jpeg_marker_writer pub; /* public fields */ |
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89 | |
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90 | unsigned int last_restart_interval; /* last DRI value emitted; 0 after SOI */ |
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91 | } my_marker_writer; |
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92 | |
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93 | typedef my_marker_writer * my_marker_ptr; |
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94 | |
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95 | |
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96 | /* |
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97 | * Basic output routines. |
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98 | * |
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99 | * Note that we do not support suspension while writing a marker. |
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100 | * Therefore, an application using suspension must ensure that there is |
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101 | * enough buffer space for the initial markers (typ. 600-700 bytes) before |
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102 | * calling jpeg_start_compress, and enough space to write the trailing EOI |
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103 | * (a few bytes) before calling jpeg_finish_compress. Multipass compression |
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104 | * modes are not supported at all with suspension, so those two are the only |
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105 | * points where markers will be written. |
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106 | */ |
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107 | |
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108 | LOCAL(void) |
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109 | emit_byte (j_compress_ptr cinfo, int val) |
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110 | /* Emit a byte */ |
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111 | { |
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112 | struct jpeg_destination_mgr * dest = cinfo->dest; |
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113 | |
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114 | *(dest->next_output_byte)++ = (JOCTET) val; |
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115 | if (--dest->free_in_buffer == 0) { |
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116 | if (! (*dest->empty_output_buffer) (cinfo)) |
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117 | ERREXIT(cinfo, JERR_CANT_SUSPEND); |
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118 | } |
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119 | } |
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120 | |
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121 | |
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122 | LOCAL(void) |
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123 | emit_marker (j_compress_ptr cinfo, JPEG_MARKER mark) |
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124 | /* Emit a marker code */ |
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125 | { |
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126 | emit_byte(cinfo, 0xFF); |
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127 | emit_byte(cinfo, (int) mark); |
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128 | } |
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129 | |
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130 | |
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131 | LOCAL(void) |
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132 | emit_2bytes (j_compress_ptr cinfo, int value) |
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133 | /* Emit a 2-byte integer; these are always MSB first in JPEG files */ |
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134 | { |
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135 | emit_byte(cinfo, (value >> 8) & 0xFF); |
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136 | emit_byte(cinfo, value & 0xFF); |
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137 | } |
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138 | |
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139 | |
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140 | /* |
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141 | * Routines to write specific marker types. |
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142 | */ |
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143 | |
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144 | LOCAL(int) |
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145 | emit_dqt (j_compress_ptr cinfo, int index) |
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146 | /* Emit a DQT marker */ |
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147 | /* Returns the precision used (0 = 8bits, 1 = 16bits) for baseline checking */ |
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148 | { |
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149 | JQUANT_TBL * qtbl = cinfo->quant_tbl_ptrs[index]; |
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150 | int prec; |
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151 | int i; |
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152 | |
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153 | if (qtbl == NULL) |
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154 | ERREXIT1(cinfo, JERR_NO_QUANT_TABLE, index); |
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155 | |
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156 | prec = 0; |
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157 | for (i = 0; i <= cinfo->lim_Se; i++) { |
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158 | if (qtbl->quantval[cinfo->natural_order[i]] > 255) |
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159 | prec = 1; |
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160 | } |
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161 | |
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162 | if (! qtbl->sent_table) { |
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163 | emit_marker(cinfo, M_DQT); |
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164 | |
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165 | emit_2bytes(cinfo, |
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166 | prec ? cinfo->lim_Se * 2 + 2 + 1 + 2 : cinfo->lim_Se + 1 + 1 + 2); |
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167 | |
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168 | emit_byte(cinfo, index + (prec<<4)); |
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169 | |
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170 | for (i = 0; i <= cinfo->lim_Se; i++) { |
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171 | /* The table entries must be emitted in zigzag order. */ |
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172 | unsigned int qval = qtbl->quantval[cinfo->natural_order[i]]; |
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173 | if (prec) |
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174 | emit_byte(cinfo, (int) (qval >> 8)); |
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175 | emit_byte(cinfo, (int) (qval & 0xFF)); |
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176 | } |
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177 | |
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178 | qtbl->sent_table = TRUE; |
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179 | } |
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180 | |
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181 | return prec; |
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182 | } |
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183 | |
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184 | |
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185 | LOCAL(void) |
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186 | emit_dht (j_compress_ptr cinfo, int index, boolean is_ac) |
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187 | /* Emit a DHT marker */ |
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188 | { |
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189 | JHUFF_TBL * htbl; |
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190 | int length, i; |
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191 | |
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192 | if (is_ac) { |
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193 | htbl = cinfo->ac_huff_tbl_ptrs[index]; |
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194 | index += 0x10; /* output index has AC bit set */ |
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195 | } else { |
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196 | htbl = cinfo->dc_huff_tbl_ptrs[index]; |
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197 | } |
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198 | |
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199 | if (htbl == NULL) |
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200 | ERREXIT1(cinfo, JERR_NO_HUFF_TABLE, index); |
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201 | |
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202 | if (! htbl->sent_table) { |
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203 | emit_marker(cinfo, M_DHT); |
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204 | |
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205 | length = 0; |
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206 | for (i = 1; i <= 16; i++) |
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207 | length += htbl->bits[i]; |
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208 | |
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209 | emit_2bytes(cinfo, length + 2 + 1 + 16); |
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210 | emit_byte(cinfo, index); |
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211 | |
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212 | for (i = 1; i <= 16; i++) |
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213 | emit_byte(cinfo, htbl->bits[i]); |
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214 | |
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215 | for (i = 0; i < length; i++) |
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216 | emit_byte(cinfo, htbl->huffval[i]); |
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217 | |
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218 | htbl->sent_table = TRUE; |
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219 | } |
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220 | } |
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221 | |
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222 | |
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223 | LOCAL(void) |
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224 | emit_dac (j_compress_ptr cinfo) |
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225 | /* Emit a DAC marker */ |
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226 | /* Since the useful info is so small, we want to emit all the tables in */ |
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227 | /* one DAC marker. Therefore this routine does its own scan of the table. */ |
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228 | { |
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229 | #ifdef C_ARITH_CODING_SUPPORTED |
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230 | char dc_in_use[NUM_ARITH_TBLS]; |
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231 | char ac_in_use[NUM_ARITH_TBLS]; |
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232 | int length, i; |
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233 | jpeg_component_info *compptr; |
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234 | |
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235 | for (i = 0; i < NUM_ARITH_TBLS; i++) |
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236 | dc_in_use[i] = ac_in_use[i] = 0; |
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237 | |
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238 | for (i = 0; i < cinfo->comps_in_scan; i++) { |
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239 | compptr = cinfo->cur_comp_info[i]; |
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240 | /* DC needs no table for refinement scan */ |
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241 | if (cinfo->Ss == 0 && cinfo->Ah == 0) |
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242 | dc_in_use[compptr->dc_tbl_no] = 1; |
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243 | /* AC needs no table when not present */ |
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244 | if (cinfo->Se) |
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245 | ac_in_use[compptr->ac_tbl_no] = 1; |
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246 | } |
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247 | |
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248 | length = 0; |
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249 | for (i = 0; i < NUM_ARITH_TBLS; i++) |
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250 | length += dc_in_use[i] + ac_in_use[i]; |
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251 | |
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252 | if (length) { |
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253 | emit_marker(cinfo, M_DAC); |
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254 | |
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255 | emit_2bytes(cinfo, length*2 + 2); |
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256 | |
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257 | for (i = 0; i < NUM_ARITH_TBLS; i++) { |
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258 | if (dc_in_use[i]) { |
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259 | emit_byte(cinfo, i); |
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260 | emit_byte(cinfo, cinfo->arith_dc_L[i] + (cinfo->arith_dc_U[i]<<4)); |
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261 | } |
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262 | if (ac_in_use[i]) { |
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263 | emit_byte(cinfo, i + 0x10); |
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264 | emit_byte(cinfo, cinfo->arith_ac_K[i]); |
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265 | } |
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266 | } |
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267 | } |
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268 | #endif /* C_ARITH_CODING_SUPPORTED */ |
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269 | } |
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270 | |
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271 | |
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272 | LOCAL(void) |
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273 | emit_dri (j_compress_ptr cinfo) |
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274 | /* Emit a DRI marker */ |
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275 | { |
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276 | emit_marker(cinfo, M_DRI); |
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277 | |
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278 | emit_2bytes(cinfo, 4); /* fixed length */ |
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279 | |
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280 | emit_2bytes(cinfo, (int) cinfo->restart_interval); |
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281 | } |
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282 | |
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283 | |
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284 | LOCAL(void) |
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285 | emit_sof (j_compress_ptr cinfo, JPEG_MARKER code) |
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286 | /* Emit a SOF marker */ |
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287 | { |
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288 | int ci; |
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289 | jpeg_component_info *compptr; |
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290 | |
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291 | emit_marker(cinfo, code); |
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292 | |
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293 | emit_2bytes(cinfo, 3 * cinfo->num_components + 2 + 5 + 1); /* length */ |
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294 | |
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295 | /* Make sure image isn't bigger than SOF field can handle */ |
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296 | if ((long) cinfo->jpeg_height > 65535L || |
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297 | (long) cinfo->jpeg_width > 65535L) |
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298 | ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, (unsigned int) 65535); |
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299 | |
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300 | emit_byte(cinfo, cinfo->data_precision); |
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301 | emit_2bytes(cinfo, (int) cinfo->jpeg_height); |
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302 | emit_2bytes(cinfo, (int) cinfo->jpeg_width); |
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303 | |
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304 | emit_byte(cinfo, cinfo->num_components); |
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305 | |
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306 | for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; |
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307 | ci++, compptr++) { |
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308 | emit_byte(cinfo, compptr->component_id); |
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309 | emit_byte(cinfo, (compptr->h_samp_factor << 4) + compptr->v_samp_factor); |
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310 | emit_byte(cinfo, compptr->quant_tbl_no); |
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311 | } |
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312 | } |
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313 | |
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314 | |
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315 | LOCAL(void) |
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316 | emit_sos (j_compress_ptr cinfo) |
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317 | /* Emit a SOS marker */ |
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318 | { |
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319 | int i, td, ta; |
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320 | jpeg_component_info *compptr; |
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321 | |
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322 | emit_marker(cinfo, M_SOS); |
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323 | |
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324 | emit_2bytes(cinfo, 2 * cinfo->comps_in_scan + 2 + 1 + 3); /* length */ |
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325 | |
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326 | emit_byte(cinfo, cinfo->comps_in_scan); |
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327 | |
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328 | for (i = 0; i < cinfo->comps_in_scan; i++) { |
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329 | compptr = cinfo->cur_comp_info[i]; |
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330 | emit_byte(cinfo, compptr->component_id); |
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331 | |
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332 | /* We emit 0 for unused field(s); this is recommended by the P&M text |
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333 | * but does not seem to be specified in the standard. |
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334 | */ |
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335 | |
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336 | /* DC needs no table for refinement scan */ |
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337 | td = cinfo->Ss == 0 && cinfo->Ah == 0 ? compptr->dc_tbl_no : 0; |
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338 | /* AC needs no table when not present */ |
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339 | ta = cinfo->Se ? compptr->ac_tbl_no : 0; |
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340 | |
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341 | emit_byte(cinfo, (td << 4) + ta); |
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342 | } |
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343 | |
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344 | emit_byte(cinfo, cinfo->Ss); |
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345 | emit_byte(cinfo, cinfo->Se); |
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346 | emit_byte(cinfo, (cinfo->Ah << 4) + cinfo->Al); |
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347 | } |
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348 | |
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349 | |
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350 | LOCAL(void) |
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351 | emit_pseudo_sos (j_compress_ptr cinfo) |
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352 | /* Emit a pseudo SOS marker */ |
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353 | { |
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354 | emit_marker(cinfo, M_SOS); |
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355 | |
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356 | emit_2bytes(cinfo, 2 + 1 + 3); /* length */ |
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357 | |
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358 | emit_byte(cinfo, 0); /* Ns */ |
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359 | |
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360 | emit_byte(cinfo, 0); /* Ss */ |
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361 | emit_byte(cinfo, cinfo->block_size * cinfo->block_size - 1); /* Se */ |
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362 | emit_byte(cinfo, 0); /* Ah/Al */ |
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363 | } |
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364 | |
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365 | |
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366 | LOCAL(void) |
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367 | emit_jfif_app0 (j_compress_ptr cinfo) |
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368 | /* Emit a JFIF-compliant APP0 marker */ |
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369 | { |
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370 | /* |
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371 | * Length of APP0 block (2 bytes) |
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372 | * Block ID (4 bytes - ASCII "JFIF") |
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373 | * Zero byte (1 byte to terminate the ID string) |
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374 | * Version Major, Minor (2 bytes - major first) |
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375 | * Units (1 byte - 0x00 = none, 0x01 = inch, 0x02 = cm) |
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376 | * Xdpu (2 bytes - dots per unit horizontal) |
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377 | * Ydpu (2 bytes - dots per unit vertical) |
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378 | * Thumbnail X size (1 byte) |
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379 | * Thumbnail Y size (1 byte) |
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380 | */ |
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381 | |
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382 | emit_marker(cinfo, M_APP0); |
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383 | |
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384 | emit_2bytes(cinfo, 2 + 4 + 1 + 2 + 1 + 2 + 2 + 1 + 1); /* length */ |
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385 | |
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386 | emit_byte(cinfo, 0x4A); /* Identifier: ASCII "JFIF" */ |
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387 | emit_byte(cinfo, 0x46); |
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388 | emit_byte(cinfo, 0x49); |
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389 | emit_byte(cinfo, 0x46); |
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390 | emit_byte(cinfo, 0); |
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391 | emit_byte(cinfo, cinfo->JFIF_major_version); /* Version fields */ |
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392 | emit_byte(cinfo, cinfo->JFIF_minor_version); |
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393 | emit_byte(cinfo, cinfo->density_unit); /* Pixel size information */ |
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394 | emit_2bytes(cinfo, (int) cinfo->X_density); |
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395 | emit_2bytes(cinfo, (int) cinfo->Y_density); |
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396 | emit_byte(cinfo, 0); /* No thumbnail image */ |
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397 | emit_byte(cinfo, 0); |
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398 | } |
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399 | |
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400 | |
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401 | LOCAL(void) |
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402 | emit_adobe_app14 (j_compress_ptr cinfo) |
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403 | /* Emit an Adobe APP14 marker */ |
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404 | { |
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405 | /* |
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406 | * Length of APP14 block (2 bytes) |
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407 | * Block ID (5 bytes - ASCII "Adobe") |
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408 | * Version Number (2 bytes - currently 100) |
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409 | * Flags0 (2 bytes - currently 0) |
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410 | * Flags1 (2 bytes - currently 0) |
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411 | * Color transform (1 byte) |
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412 | * |
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413 | * Although Adobe TN 5116 mentions Version = 101, all the Adobe files |
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414 | * now in circulation seem to use Version = 100, so that's what we write. |
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415 | * |
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416 | * We write the color transform byte as 1 if the JPEG color space is |
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417 | * YCbCr, 2 if it's YCCK, 0 otherwise. Adobe's definition has to do with |
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418 | * whether the encoder performed a transformation, which is pretty useless. |
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419 | */ |
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420 | |
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421 | emit_marker(cinfo, M_APP14); |
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422 | |
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423 | emit_2bytes(cinfo, 2 + 5 + 2 + 2 + 2 + 1); /* length */ |
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424 | |
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425 | emit_byte(cinfo, 0x41); /* Identifier: ASCII "Adobe" */ |
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426 | emit_byte(cinfo, 0x64); |
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427 | emit_byte(cinfo, 0x6F); |
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428 | emit_byte(cinfo, 0x62); |
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429 | emit_byte(cinfo, 0x65); |
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430 | emit_2bytes(cinfo, 100); /* Version */ |
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431 | emit_2bytes(cinfo, 0); /* Flags0 */ |
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432 | emit_2bytes(cinfo, 0); /* Flags1 */ |
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433 | switch (cinfo->jpeg_color_space) { |
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434 | case JCS_YCbCr: |
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435 | emit_byte(cinfo, 1); /* Color transform = 1 */ |
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436 | break; |
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437 | case JCS_YCCK: |
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438 | emit_byte(cinfo, 2); /* Color transform = 2 */ |
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439 | break; |
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440 | default: |
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441 | emit_byte(cinfo, 0); /* Color transform = 0 */ |
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442 | break; |
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443 | } |
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444 | } |
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445 | |
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446 | |
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447 | /* |
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448 | * These routines allow writing an arbitrary marker with parameters. |
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449 | * The only intended use is to emit COM or APPn markers after calling |
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450 | * write_file_header and before calling write_frame_header. |
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451 | * Other uses are not guaranteed to produce desirable results. |
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452 | * Counting the parameter bytes properly is the caller's responsibility. |
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453 | */ |
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454 | |
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455 | METHODDEF(void) |
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456 | write_marker_header (j_compress_ptr cinfo, int marker, unsigned int datalen) |
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457 | /* Emit an arbitrary marker header */ |
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458 | { |
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459 | if (datalen > (unsigned int) 65533) /* safety check */ |
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460 | ERREXIT(cinfo, JERR_BAD_LENGTH); |
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461 | |
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462 | emit_marker(cinfo, (JPEG_MARKER) marker); |
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463 | |
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464 | emit_2bytes(cinfo, (int) (datalen + 2)); /* total length */ |
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465 | } |
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466 | |
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467 | METHODDEF(void) |
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468 | write_marker_byte (j_compress_ptr cinfo, int val) |
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469 | /* Emit one byte of marker parameters following write_marker_header */ |
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470 | { |
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471 | emit_byte(cinfo, val); |
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472 | } |
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473 | |
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474 | |
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475 | /* |
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476 | * Write datastream header. |
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477 | * This consists of an SOI and optional APPn markers. |
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478 | * We recommend use of the JFIF marker, but not the Adobe marker, |
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479 | * when using YCbCr or grayscale data. The JFIF marker should NOT |
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480 | * be used for any other JPEG colorspace. The Adobe marker is helpful |
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481 | * to distinguish RGB, CMYK, and YCCK colorspaces. |
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482 | * Note that an application can write additional header markers after |
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483 | * jpeg_start_compress returns. |
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484 | */ |
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485 | |
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486 | METHODDEF(void) |
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487 | write_file_header (j_compress_ptr cinfo) |
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488 | { |
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489 | my_marker_ptr marker = (my_marker_ptr) cinfo->marker; |
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490 | |
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491 | emit_marker(cinfo, M_SOI); /* first the SOI */ |
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492 | |
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493 | /* SOI is defined to reset restart interval to 0 */ |
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494 | marker->last_restart_interval = 0; |
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495 | |
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496 | if (cinfo->write_JFIF_header) /* next an optional JFIF APP0 */ |
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497 | emit_jfif_app0(cinfo); |
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498 | if (cinfo->write_Adobe_marker) /* next an optional Adobe APP14 */ |
---|
499 | emit_adobe_app14(cinfo); |
---|
500 | } |
---|
501 | |
---|
502 | |
---|
503 | /* |
---|
504 | * Write frame header. |
---|
505 | * This consists of DQT and SOFn markers, and a conditional pseudo SOS marker. |
---|
506 | * Note that we do not emit the SOF until we have emitted the DQT(s). |
---|
507 | * This avoids compatibility problems with incorrect implementations that |
---|
508 | * try to error-check the quant table numbers as soon as they see the SOF. |
---|
509 | */ |
---|
510 | |
---|
511 | METHODDEF(void) |
---|
512 | write_frame_header (j_compress_ptr cinfo) |
---|
513 | { |
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514 | int ci, prec; |
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515 | boolean is_baseline; |
---|
516 | jpeg_component_info *compptr; |
---|
517 | |
---|
518 | /* Emit DQT for each quantization table. |
---|
519 | * Note that emit_dqt() suppresses any duplicate tables. |
---|
520 | */ |
---|
521 | prec = 0; |
---|
522 | for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; |
---|
523 | ci++, compptr++) { |
---|
524 | prec += emit_dqt(cinfo, compptr->quant_tbl_no); |
---|
525 | } |
---|
526 | /* now prec is nonzero iff there are any 16-bit quant tables. */ |
---|
527 | |
---|
528 | /* Check for a non-baseline specification. |
---|
529 | * Note we assume that Huffman table numbers won't be changed later. |
---|
530 | */ |
---|
531 | if (cinfo->arith_code || cinfo->progressive_mode || |
---|
532 | cinfo->data_precision != 8 || cinfo->block_size != DCTSIZE) { |
---|
533 | is_baseline = FALSE; |
---|
534 | } else { |
---|
535 | is_baseline = TRUE; |
---|
536 | for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; |
---|
537 | ci++, compptr++) { |
---|
538 | if (compptr->dc_tbl_no > 1 || compptr->ac_tbl_no > 1) |
---|
539 | is_baseline = FALSE; |
---|
540 | } |
---|
541 | if (prec && is_baseline) { |
---|
542 | is_baseline = FALSE; |
---|
543 | /* If it's baseline except for quantizer size, warn the user */ |
---|
544 | TRACEMS(cinfo, 0, JTRC_16BIT_TABLES); |
---|
545 | } |
---|
546 | } |
---|
547 | |
---|
548 | /* Emit the proper SOF marker */ |
---|
549 | if (cinfo->arith_code) { |
---|
550 | if (cinfo->progressive_mode) |
---|
551 | emit_sof(cinfo, M_SOF10); /* SOF code for progressive arithmetic */ |
---|
552 | else |
---|
553 | emit_sof(cinfo, M_SOF9); /* SOF code for sequential arithmetic */ |
---|
554 | } else { |
---|
555 | if (cinfo->progressive_mode) |
---|
556 | emit_sof(cinfo, M_SOF2); /* SOF code for progressive Huffman */ |
---|
557 | else if (is_baseline) |
---|
558 | emit_sof(cinfo, M_SOF0); /* SOF code for baseline implementation */ |
---|
559 | else |
---|
560 | emit_sof(cinfo, M_SOF1); /* SOF code for non-baseline Huffman file */ |
---|
561 | } |
---|
562 | |
---|
563 | /* Check to emit pseudo SOS marker */ |
---|
564 | if (cinfo->progressive_mode && cinfo->block_size != DCTSIZE) |
---|
565 | emit_pseudo_sos(cinfo); |
---|
566 | } |
---|
567 | |
---|
568 | |
---|
569 | /* |
---|
570 | * Write scan header. |
---|
571 | * This consists of DHT or DAC markers, optional DRI, and SOS. |
---|
572 | * Compressed data will be written following the SOS. |
---|
573 | */ |
---|
574 | |
---|
575 | METHODDEF(void) |
---|
576 | write_scan_header (j_compress_ptr cinfo) |
---|
577 | { |
---|
578 | my_marker_ptr marker = (my_marker_ptr) cinfo->marker; |
---|
579 | int i; |
---|
580 | jpeg_component_info *compptr; |
---|
581 | |
---|
582 | if (cinfo->arith_code) { |
---|
583 | /* Emit arith conditioning info. We may have some duplication |
---|
584 | * if the file has multiple scans, but it's so small it's hardly |
---|
585 | * worth worrying about. |
---|
586 | */ |
---|
587 | emit_dac(cinfo); |
---|
588 | } else { |
---|
589 | /* Emit Huffman tables. |
---|
590 | * Note that emit_dht() suppresses any duplicate tables. |
---|
591 | */ |
---|
592 | for (i = 0; i < cinfo->comps_in_scan; i++) { |
---|
593 | compptr = cinfo->cur_comp_info[i]; |
---|
594 | /* DC needs no table for refinement scan */ |
---|
595 | if (cinfo->Ss == 0 && cinfo->Ah == 0) |
---|
596 | emit_dht(cinfo, compptr->dc_tbl_no, FALSE); |
---|
597 | /* AC needs no table when not present */ |
---|
598 | if (cinfo->Se) |
---|
599 | emit_dht(cinfo, compptr->ac_tbl_no, TRUE); |
---|
600 | } |
---|
601 | } |
---|
602 | |
---|
603 | /* Emit DRI if required --- note that DRI value could change for each scan. |
---|
604 | * We avoid wasting space with unnecessary DRIs, however. |
---|
605 | */ |
---|
606 | if (cinfo->restart_interval != marker->last_restart_interval) { |
---|
607 | emit_dri(cinfo); |
---|
608 | marker->last_restart_interval = cinfo->restart_interval; |
---|
609 | } |
---|
610 | |
---|
611 | emit_sos(cinfo); |
---|
612 | } |
---|
613 | |
---|
614 | |
---|
615 | /* |
---|
616 | * Write datastream trailer. |
---|
617 | */ |
---|
618 | |
---|
619 | METHODDEF(void) |
---|
620 | write_file_trailer (j_compress_ptr cinfo) |
---|
621 | { |
---|
622 | emit_marker(cinfo, M_EOI); |
---|
623 | } |
---|
624 | |
---|
625 | |
---|
626 | /* |
---|
627 | * Write an abbreviated table-specification datastream. |
---|
628 | * This consists of SOI, DQT and DHT tables, and EOI. |
---|
629 | * Any table that is defined and not marked sent_table = TRUE will be |
---|
630 | * emitted. Note that all tables will be marked sent_table = TRUE at exit. |
---|
631 | */ |
---|
632 | |
---|
633 | METHODDEF(void) |
---|
634 | write_tables_only (j_compress_ptr cinfo) |
---|
635 | { |
---|
636 | int i; |
---|
637 | |
---|
638 | emit_marker(cinfo, M_SOI); |
---|
639 | |
---|
640 | for (i = 0; i < NUM_QUANT_TBLS; i++) { |
---|
641 | if (cinfo->quant_tbl_ptrs[i] != NULL) |
---|
642 | (void) emit_dqt(cinfo, i); |
---|
643 | } |
---|
644 | |
---|
645 | if (! cinfo->arith_code) { |
---|
646 | for (i = 0; i < NUM_HUFF_TBLS; i++) { |
---|
647 | if (cinfo->dc_huff_tbl_ptrs[i] != NULL) |
---|
648 | emit_dht(cinfo, i, FALSE); |
---|
649 | if (cinfo->ac_huff_tbl_ptrs[i] != NULL) |
---|
650 | emit_dht(cinfo, i, TRUE); |
---|
651 | } |
---|
652 | } |
---|
653 | |
---|
654 | emit_marker(cinfo, M_EOI); |
---|
655 | } |
---|
656 | |
---|
657 | |
---|
658 | /* |
---|
659 | * Initialize the marker writer module. |
---|
660 | */ |
---|
661 | |
---|
662 | GLOBAL(void) |
---|
663 | jinit_marker_writer (j_compress_ptr cinfo) |
---|
664 | { |
---|
665 | my_marker_ptr marker; |
---|
666 | |
---|
667 | /* Create the subobject */ |
---|
668 | marker = (my_marker_ptr) |
---|
669 | (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, |
---|
670 | SIZEOF(my_marker_writer)); |
---|
671 | cinfo->marker = (struct jpeg_marker_writer *) marker; |
---|
672 | /* Initialize method pointers */ |
---|
673 | marker->pub.write_file_header = write_file_header; |
---|
674 | marker->pub.write_frame_header = write_frame_header; |
---|
675 | marker->pub.write_scan_header = write_scan_header; |
---|
676 | marker->pub.write_file_trailer = write_file_trailer; |
---|
677 | marker->pub.write_tables_only = write_tables_only; |
---|
678 | marker->pub.write_marker_header = write_marker_header; |
---|
679 | marker->pub.write_marker_byte = write_marker_byte; |
---|
680 | /* Initialize private state */ |
---|
681 | marker->last_restart_interval = 0; |
---|
682 | } |
---|