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6417 | ashmew2 | 1 | /* |
2 | * jctrans.c |
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3 | * |
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4 | * Copyright (C) 1995-1998, Thomas G. Lane. |
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5 | * This file is part of the Independent JPEG Group's software. |
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6 | * For conditions of distribution and use, see the accompanying README file. |
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7 | * |
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8 | * This file contains library routines for transcoding compression, |
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9 | * that is, writing raw DCT coefficient arrays to an output JPEG file. |
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10 | * The routines in jcapimin.c will also be needed by a transcoder. |
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11 | */ |
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12 | |||
13 | #define JPEG_INTERNALS |
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14 | #include "jinclude.h" |
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15 | #include "jpeglib.h" |
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16 | |||
17 | |||
18 | /* Forward declarations */ |
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19 | LOCAL(void) transencode_master_selection |
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20 | JPP((j_compress_ptr cinfo, jvirt_barray_ptr * coef_arrays)); |
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21 | LOCAL(void) transencode_coef_controller |
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22 | JPP((j_compress_ptr cinfo, jvirt_barray_ptr * coef_arrays)); |
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23 | |||
24 | |||
25 | /* |
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26 | * Compression initialization for writing raw-coefficient data. |
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27 | * Before calling this, all parameters and a data destination must be set up. |
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28 | * Call jpeg_finish_compress() to actually write the data. |
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29 | * |
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30 | * The number of passed virtual arrays must match cinfo->num_components. |
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31 | * Note that the virtual arrays need not be filled or even realized at |
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32 | * the time write_coefficients is called; indeed, if the virtual arrays |
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33 | * were requested from this compression object's memory manager, they |
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34 | * typically will be realized during this routine and filled afterwards. |
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35 | */ |
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36 | |||
37 | GLOBAL(void) |
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38 | jpeg_write_coefficients (j_compress_ptr cinfo, jvirt_barray_ptr * coef_arrays) |
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39 | { |
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40 | if (cinfo->global_state != CSTATE_START) |
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41 | ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); |
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42 | /* Mark all tables to be written */ |
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43 | jpeg_suppress_tables(cinfo, FALSE); |
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44 | /* (Re)initialize error mgr and destination modules */ |
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45 | (*cinfo->err->reset_error_mgr) ((j_common_ptr) cinfo); |
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46 | (*cinfo->dest->init_destination) (cinfo); |
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47 | /* Perform master selection of active modules */ |
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48 | transencode_master_selection(cinfo, coef_arrays); |
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49 | /* Wait for jpeg_finish_compress() call */ |
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50 | cinfo->next_scanline = 0; /* so jpeg_write_marker works */ |
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51 | cinfo->global_state = CSTATE_WRCOEFS; |
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52 | } |
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53 | |||
54 | |||
55 | /* |
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56 | * Initialize the compression object with default parameters, |
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57 | * then copy from the source object all parameters needed for lossless |
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58 | * transcoding. Parameters that can be varied without loss (such as |
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59 | * scan script and Huffman optimization) are left in their default states. |
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60 | */ |
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61 | |||
62 | GLOBAL(void) |
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63 | jpeg_copy_critical_parameters (j_decompress_ptr srcinfo, |
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64 | j_compress_ptr dstinfo) |
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65 | { |
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66 | JQUANT_TBL ** qtblptr; |
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67 | jpeg_component_info *incomp, *outcomp; |
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68 | JQUANT_TBL *c_quant, *slot_quant; |
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69 | int tblno, ci, coefi; |
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70 | |||
71 | /* Safety check to ensure start_compress not called yet. */ |
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72 | if (dstinfo->global_state != CSTATE_START) |
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73 | ERREXIT1(dstinfo, JERR_BAD_STATE, dstinfo->global_state); |
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74 | /* Copy fundamental image dimensions */ |
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75 | dstinfo->image_width = srcinfo->image_width; |
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76 | dstinfo->image_height = srcinfo->image_height; |
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77 | dstinfo->input_components = srcinfo->num_components; |
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78 | dstinfo->in_color_space = srcinfo->jpeg_color_space; |
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79 | /* Initialize all parameters to default values */ |
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80 | jpeg_set_defaults(dstinfo); |
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81 | /* jpeg_set_defaults may choose wrong colorspace, eg YCbCr if input is RGB. |
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82 | * Fix it to get the right header markers for the image colorspace. |
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83 | */ |
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84 | jpeg_set_colorspace(dstinfo, srcinfo->jpeg_color_space); |
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85 | dstinfo->data_precision = srcinfo->data_precision; |
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86 | dstinfo->CCIR601_sampling = srcinfo->CCIR601_sampling; |
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87 | /* Copy the source's quantization tables. */ |
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88 | for (tblno = 0; tblno < NUM_QUANT_TBLS; tblno++) { |
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89 | if (srcinfo->quant_tbl_ptrs[tblno] != NULL) { |
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90 | qtblptr = & dstinfo->quant_tbl_ptrs[tblno]; |
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91 | if (*qtblptr == NULL) |
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92 | *qtblptr = jpeg_alloc_quant_table((j_common_ptr) dstinfo); |
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93 | MEMCOPY((*qtblptr)->quantval, |
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94 | srcinfo->quant_tbl_ptrs[tblno]->quantval, |
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95 | SIZEOF((*qtblptr)->quantval)); |
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96 | (*qtblptr)->sent_table = FALSE; |
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97 | } |
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98 | } |
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99 | /* Copy the source's per-component info. |
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100 | * Note we assume jpeg_set_defaults has allocated the dest comp_info array. |
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101 | */ |
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102 | dstinfo->num_components = srcinfo->num_components; |
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103 | if (dstinfo->num_components < 1 || dstinfo->num_components > MAX_COMPONENTS) |
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104 | ERREXIT2(dstinfo, JERR_COMPONENT_COUNT, dstinfo->num_components, |
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105 | MAX_COMPONENTS); |
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106 | for (ci = 0, incomp = srcinfo->comp_info, outcomp = dstinfo->comp_info; |
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107 | ci < dstinfo->num_components; ci++, incomp++, outcomp++) { |
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108 | outcomp->component_id = incomp->component_id; |
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109 | outcomp->h_samp_factor = incomp->h_samp_factor; |
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110 | outcomp->v_samp_factor = incomp->v_samp_factor; |
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111 | outcomp->quant_tbl_no = incomp->quant_tbl_no; |
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112 | /* Make sure saved quantization table for component matches the qtable |
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113 | * slot. If not, the input file re-used this qtable slot. |
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114 | * IJG encoder currently cannot duplicate this. |
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115 | */ |
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116 | tblno = outcomp->quant_tbl_no; |
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117 | if (tblno < 0 || tblno >= NUM_QUANT_TBLS || |
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118 | srcinfo->quant_tbl_ptrs[tblno] == NULL) |
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119 | ERREXIT1(dstinfo, JERR_NO_QUANT_TABLE, tblno); |
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120 | slot_quant = srcinfo->quant_tbl_ptrs[tblno]; |
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121 | c_quant = incomp->quant_table; |
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122 | if (c_quant != NULL) { |
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123 | for (coefi = 0; coefi < DCTSIZE2; coefi++) { |
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124 | if (c_quant->quantval[coefi] != slot_quant->quantval[coefi]) |
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125 | ERREXIT1(dstinfo, JERR_MISMATCHED_QUANT_TABLE, tblno); |
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126 | } |
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127 | } |
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128 | /* Note: we do not copy the source's Huffman table assignments; |
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129 | * instead we rely on jpeg_set_colorspace to have made a suitable choice. |
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130 | */ |
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131 | } |
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132 | /* Also copy JFIF version and resolution information, if available. |
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133 | * Strictly speaking this isn't "critical" info, but it's nearly |
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134 | * always appropriate to copy it if available. In particular, |
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135 | * if the application chooses to copy JFIF 1.02 extension markers from |
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136 | * the source file, we need to copy the version to make sure we don't |
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137 | * emit a file that has 1.02 extensions but a claimed version of 1.01. |
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138 | * We will *not*, however, copy version info from mislabeled "2.01" files. |
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139 | */ |
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140 | if (srcinfo->saw_JFIF_marker) { |
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141 | if (srcinfo->JFIF_major_version == 1) { |
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142 | dstinfo->JFIF_major_version = srcinfo->JFIF_major_version; |
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143 | dstinfo->JFIF_minor_version = srcinfo->JFIF_minor_version; |
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144 | } |
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145 | dstinfo->density_unit = srcinfo->density_unit; |
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146 | dstinfo->X_density = srcinfo->X_density; |
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147 | dstinfo->Y_density = srcinfo->Y_density; |
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148 | } |
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149 | } |
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150 | |||
151 | |||
152 | /* |
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153 | * Master selection of compression modules for transcoding. |
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154 | * This substitutes for jcinit.c's initialization of the full compressor. |
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155 | */ |
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156 | |||
157 | LOCAL(void) |
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158 | transencode_master_selection (j_compress_ptr cinfo, |
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159 | jvirt_barray_ptr * coef_arrays) |
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160 | { |
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161 | /* Although we don't actually use input_components for transcoding, |
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162 | * jcmaster.c's initial_setup will complain if input_components is 0. |
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163 | */ |
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164 | cinfo->input_components = 1; |
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165 | /* Initialize master control (includes parameter checking/processing) */ |
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166 | jinit_c_master_control(cinfo, TRUE /* transcode only */); |
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167 | |||
168 | /* Entropy encoding: either Huffman or arithmetic coding. */ |
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169 | if (cinfo->arith_code) { |
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170 | ERREXIT(cinfo, JERR_ARITH_NOTIMPL); |
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171 | } else { |
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172 | if (cinfo->progressive_mode) { |
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173 | #ifdef C_PROGRESSIVE_SUPPORTED |
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174 | jinit_phuff_encoder(cinfo); |
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175 | #else |
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176 | ERREXIT(cinfo, JERR_NOT_COMPILED); |
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177 | #endif |
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178 | } else |
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179 | jinit_huff_encoder(cinfo); |
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180 | } |
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181 | |||
182 | /* We need a special coefficient buffer controller. */ |
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183 | transencode_coef_controller(cinfo, coef_arrays); |
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184 | |||
185 | jinit_marker_writer(cinfo); |
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186 | |||
187 | /* We can now tell the memory manager to allocate virtual arrays. */ |
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188 | (*cinfo->mem->realize_virt_arrays) ((j_common_ptr) cinfo); |
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189 | |||
190 | /* Write the datastream header (SOI, JFIF) immediately. |
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191 | * Frame and scan headers are postponed till later. |
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192 | * This lets application insert special markers after the SOI. |
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193 | */ |
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194 | (*cinfo->marker->write_file_header) (cinfo); |
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195 | } |
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196 | |||
197 | |||
198 | /* |
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199 | * The rest of this file is a special implementation of the coefficient |
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200 | * buffer controller. This is similar to jccoefct.c, but it handles only |
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201 | * output from presupplied virtual arrays. Furthermore, we generate any |
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202 | * dummy padding blocks on-the-fly rather than expecting them to be present |
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203 | * in the arrays. |
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204 | */ |
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205 | |||
206 | /* Private buffer controller object */ |
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207 | |||
208 | typedef struct { |
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209 | struct jpeg_c_coef_controller pub; /* public fields */ |
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210 | |||
211 | JDIMENSION iMCU_row_num; /* iMCU row # within image */ |
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212 | JDIMENSION mcu_ctr; /* counts MCUs processed in current row */ |
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213 | int MCU_vert_offset; /* counts MCU rows within iMCU row */ |
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214 | int MCU_rows_per_iMCU_row; /* number of such rows needed */ |
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215 | |||
216 | /* Virtual block array for each component. */ |
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217 | jvirt_barray_ptr * whole_image; |
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218 | |||
219 | /* Workspace for constructing dummy blocks at right/bottom edges. */ |
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220 | JBLOCKROW dummy_buffer[C_MAX_BLOCKS_IN_MCU]; |
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221 | } my_coef_controller; |
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222 | |||
223 | typedef my_coef_controller * my_coef_ptr; |
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224 | |||
225 | |||
226 | LOCAL(void) |
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227 | start_iMCU_row (j_compress_ptr cinfo) |
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228 | /* Reset within-iMCU-row counters for a new row */ |
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229 | { |
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230 | my_coef_ptr coef = (my_coef_ptr) cinfo->coef; |
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231 | |||
232 | /* In an interleaved scan, an MCU row is the same as an iMCU row. |
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233 | * In a noninterleaved scan, an iMCU row has v_samp_factor MCU rows. |
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234 | * But at the bottom of the image, process only what's left. |
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235 | */ |
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236 | if (cinfo->comps_in_scan > 1) { |
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237 | coef->MCU_rows_per_iMCU_row = 1; |
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238 | } else { |
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239 | if (coef->iMCU_row_num < (cinfo->total_iMCU_rows-1)) |
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240 | coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->v_samp_factor; |
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241 | else |
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242 | coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->last_row_height; |
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243 | } |
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244 | |||
245 | coef->mcu_ctr = 0; |
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246 | coef->MCU_vert_offset = 0; |
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247 | } |
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248 | |||
249 | |||
250 | /* |
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251 | * Initialize for a processing pass. |
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252 | */ |
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253 | |||
254 | METHODDEF(void) |
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255 | start_pass_coef (j_compress_ptr cinfo, J_BUF_MODE pass_mode) |
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256 | { |
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257 | my_coef_ptr coef = (my_coef_ptr) cinfo->coef; |
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258 | |||
259 | if (pass_mode != JBUF_CRANK_DEST) |
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260 | ERREXIT(cinfo, JERR_BAD_BUFFER_MODE); |
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261 | |||
262 | coef->iMCU_row_num = 0; |
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263 | start_iMCU_row(cinfo); |
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264 | } |
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265 | |||
266 | |||
267 | /* |
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268 | * Process some data. |
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269 | * We process the equivalent of one fully interleaved MCU row ("iMCU" row) |
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270 | * per call, ie, v_samp_factor block rows for each component in the scan. |
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271 | * The data is obtained from the virtual arrays and fed to the entropy coder. |
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272 | * Returns TRUE if the iMCU row is completed, FALSE if suspended. |
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273 | * |
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274 | * NB: input_buf is ignored; it is likely to be a NULL pointer. |
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275 | */ |
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276 | |||
277 | METHODDEF(boolean) |
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278 | compress_output (j_compress_ptr cinfo, JSAMPIMAGE input_buf) |
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279 | { |
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280 | my_coef_ptr coef = (my_coef_ptr) cinfo->coef; |
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281 | JDIMENSION MCU_col_num; /* index of current MCU within row */ |
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282 | JDIMENSION last_MCU_col = cinfo->MCUs_per_row - 1; |
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283 | JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1; |
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284 | int blkn, ci, xindex, yindex, yoffset, blockcnt; |
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285 | JDIMENSION start_col; |
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286 | JBLOCKARRAY buffer[MAX_COMPS_IN_SCAN]; |
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287 | JBLOCKROW MCU_buffer[C_MAX_BLOCKS_IN_MCU]; |
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288 | JBLOCKROW buffer_ptr; |
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289 | jpeg_component_info *compptr; |
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290 | |||
291 | /* Align the virtual buffers for the components used in this scan. */ |
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292 | for (ci = 0; ci < cinfo->comps_in_scan; ci++) { |
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293 | compptr = cinfo->cur_comp_info[ci]; |
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294 | buffer[ci] = (*cinfo->mem->access_virt_barray) |
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295 | ((j_common_ptr) cinfo, coef->whole_image[compptr->component_index], |
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296 | coef->iMCU_row_num * compptr->v_samp_factor, |
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297 | (JDIMENSION) compptr->v_samp_factor, FALSE); |
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298 | } |
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299 | |||
300 | /* Loop to process one whole iMCU row */ |
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301 | for (yoffset = coef->MCU_vert_offset; yoffset < coef->MCU_rows_per_iMCU_row; |
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302 | yoffset++) { |
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303 | for (MCU_col_num = coef->mcu_ctr; MCU_col_num < cinfo->MCUs_per_row; |
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304 | MCU_col_num++) { |
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305 | /* Construct list of pointers to DCT blocks belonging to this MCU */ |
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306 | blkn = 0; /* index of current DCT block within MCU */ |
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307 | for (ci = 0; ci < cinfo->comps_in_scan; ci++) { |
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308 | compptr = cinfo->cur_comp_info[ci]; |
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309 | start_col = MCU_col_num * compptr->MCU_width; |
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310 | blockcnt = (MCU_col_num < last_MCU_col) ? compptr->MCU_width |
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311 | : compptr->last_col_width; |
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312 | for (yindex = 0; yindex < compptr->MCU_height; yindex++) { |
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313 | if (coef->iMCU_row_num < last_iMCU_row || |
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314 | yindex+yoffset < compptr->last_row_height) { |
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315 | /* Fill in pointers to real blocks in this row */ |
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316 | buffer_ptr = buffer[ci][yindex+yoffset] + start_col; |
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317 | for (xindex = 0; xindex < blockcnt; xindex++) |
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318 | MCU_buffer[blkn++] = buffer_ptr++; |
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319 | } else { |
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320 | /* At bottom of image, need a whole row of dummy blocks */ |
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321 | xindex = 0; |
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322 | } |
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323 | /* Fill in any dummy blocks needed in this row. |
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324 | * Dummy blocks are filled in the same way as in jccoefct.c: |
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325 | * all zeroes in the AC entries, DC entries equal to previous |
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326 | * block's DC value. The init routine has already zeroed the |
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327 | * AC entries, so we need only set the DC entries correctly. |
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328 | */ |
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329 | for (; xindex < compptr->MCU_width; xindex++) { |
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330 | MCU_buffer[blkn] = coef->dummy_buffer[blkn]; |
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331 | MCU_buffer[blkn][0][0] = MCU_buffer[blkn-1][0][0]; |
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332 | blkn++; |
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333 | } |
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334 | } |
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335 | } |
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336 | /* Try to write the MCU. */ |
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337 | if (! (*cinfo->entropy->encode_mcu) (cinfo, MCU_buffer)) { |
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338 | /* Suspension forced; update state counters and exit */ |
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339 | coef->MCU_vert_offset = yoffset; |
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340 | coef->mcu_ctr = MCU_col_num; |
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341 | return FALSE; |
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342 | } |
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343 | } |
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344 | /* Completed an MCU row, but perhaps not an iMCU row */ |
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345 | coef->mcu_ctr = 0; |
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346 | } |
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347 | /* Completed the iMCU row, advance counters for next one */ |
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348 | coef->iMCU_row_num++; |
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349 | start_iMCU_row(cinfo); |
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350 | return TRUE; |
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351 | } |
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352 | |||
353 | |||
354 | /* |
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355 | * Initialize coefficient buffer controller. |
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356 | * |
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357 | * Each passed coefficient array must be the right size for that |
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358 | * coefficient: width_in_blocks wide and height_in_blocks high, |
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359 | * with unitheight at least v_samp_factor. |
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360 | */ |
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361 | |||
362 | LOCAL(void) |
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363 | transencode_coef_controller (j_compress_ptr cinfo, |
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364 | jvirt_barray_ptr * coef_arrays) |
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365 | { |
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366 | my_coef_ptr coef; |
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367 | JBLOCKROW buffer; |
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368 | int i; |
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369 | |||
370 | coef = (my_coef_ptr) |
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371 | (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, |
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372 | SIZEOF(my_coef_controller)); |
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373 | cinfo->coef = (struct jpeg_c_coef_controller *) coef; |
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374 | coef->pub.start_pass = start_pass_coef; |
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375 | coef->pub.compress_data = compress_output; |
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376 | |||
377 | /* Save pointer to virtual arrays */ |
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378 | coef->whole_image = coef_arrays; |
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379 | |||
380 | /* Allocate and pre-zero space for dummy DCT blocks. */ |
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381 | buffer = (JBLOCKROW) |
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382 | (*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE, |
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383 | C_MAX_BLOCKS_IN_MCU * SIZEOF(JBLOCK)); |
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384 | jzero_far((void FAR *) buffer, C_MAX_BLOCKS_IN_MCU * SIZEOF(JBLOCK)); |
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385 | for (i = 0; i < C_MAX_BLOCKS_IN_MCU; i++) { |
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386 | coef->dummy_buffer[i] = buffer + i; |
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387 | } |
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388 | }>>>>>>>>>>>>>>>>> |