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6417 | ashmew2 | 1 | /* |
2 | * jdcoefct.c |
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3 | * |
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4 | * Copyright (C) 1994-1997, 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 the coefficient buffer controller for decompression. |
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9 | * This controller is the top level of the JPEG decompressor proper. |
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10 | * The coefficient buffer lies between entropy decoding and inverse-DCT steps. |
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11 | * |
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12 | * In buffered-image mode, this controller is the interface between |
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13 | * input-oriented processing and output-oriented processing. |
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14 | * Also, the input side (only) is used when reading a file for transcoding. |
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15 | */ |
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16 | |||
17 | #define JPEG_INTERNALS |
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18 | #include "jinclude.h" |
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19 | #include "jpeglib.h" |
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20 | |||
21 | /* Block smoothing is only applicable for progressive JPEG, so: */ |
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22 | #ifndef D_PROGRESSIVE_SUPPORTED |
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23 | #undef BLOCK_SMOOTHING_SUPPORTED |
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24 | #endif |
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25 | |||
26 | /* Private buffer controller object */ |
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27 | |||
28 | typedef struct { |
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29 | struct jpeg_d_coef_controller pub; /* public fields */ |
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30 | |||
31 | /* These variables keep track of the current location of the input side. */ |
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32 | /* cinfo->input_iMCU_row is also used for this. */ |
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33 | JDIMENSION MCU_ctr; /* counts MCUs processed in current row */ |
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34 | int MCU_vert_offset; /* counts MCU rows within iMCU row */ |
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35 | int MCU_rows_per_iMCU_row; /* number of such rows needed */ |
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36 | |||
37 | /* The output side's location is represented by cinfo->output_iMCU_row. */ |
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38 | |||
39 | /* In single-pass modes, it's sufficient to buffer just one MCU. |
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40 | * We allocate a workspace of D_MAX_BLOCKS_IN_MCU coefficient blocks, |
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41 | * and let the entropy decoder write into that workspace each time. |
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42 | * (On 80x86, the workspace is FAR even though it's not really very big; |
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43 | * this is to keep the module interfaces unchanged when a large coefficient |
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44 | * buffer is necessary.) |
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45 | * In multi-pass modes, this array points to the current MCU's blocks |
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46 | * within the virtual arrays; it is used only by the input side. |
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47 | */ |
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48 | JBLOCKROW MCU_buffer[D_MAX_BLOCKS_IN_MCU]; |
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49 | |||
50 | #ifdef D_MULTISCAN_FILES_SUPPORTED |
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51 | /* In multi-pass modes, we need a virtual block array for each component. */ |
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52 | jvirt_barray_ptr whole_image[MAX_COMPONENTS]; |
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53 | #endif |
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54 | |||
55 | #ifdef BLOCK_SMOOTHING_SUPPORTED |
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56 | /* When doing block smoothing, we latch coefficient Al values here */ |
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57 | int * coef_bits_latch; |
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58 | #define SAVED_COEFS 6 /* we save coef_bits[0..5] */ |
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59 | #endif |
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60 | } my_coef_controller; |
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61 | |||
62 | typedef my_coef_controller * my_coef_ptr; |
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63 | |||
64 | /* Forward declarations */ |
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65 | METHODDEF(int) decompress_onepass |
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66 | JPP((j_decompress_ptr cinfo, JSAMPIMAGE output_buf)); |
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67 | #ifdef D_MULTISCAN_FILES_SUPPORTED |
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68 | METHODDEF(int) decompress_data |
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69 | JPP((j_decompress_ptr cinfo, JSAMPIMAGE output_buf)); |
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70 | #endif |
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71 | #ifdef BLOCK_SMOOTHING_SUPPORTED |
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72 | LOCAL(boolean) smoothing_ok JPP((j_decompress_ptr cinfo)); |
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73 | METHODDEF(int) decompress_smooth_data |
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74 | JPP((j_decompress_ptr cinfo, JSAMPIMAGE output_buf)); |
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75 | #endif |
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76 | |||
77 | |||
78 | LOCAL(void) |
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79 | start_iMCU_row (j_decompress_ptr cinfo) |
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80 | /* Reset within-iMCU-row counters for a new row (input side) */ |
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81 | { |
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82 | my_coef_ptr coef = (my_coef_ptr) cinfo->coef; |
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83 | |||
84 | /* In an interleaved scan, an MCU row is the same as an iMCU row. |
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85 | * In a noninterleaved scan, an iMCU row has v_samp_factor MCU rows. |
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86 | * But at the bottom of the image, process only what's left. |
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87 | */ |
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88 | if (cinfo->comps_in_scan > 1) { |
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89 | coef->MCU_rows_per_iMCU_row = 1; |
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90 | } else { |
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91 | if (cinfo->input_iMCU_row < (cinfo->total_iMCU_rows-1)) |
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92 | coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->v_samp_factor; |
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93 | else |
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94 | coef->MCU_rows_per_iMCU_row = cinfo->cur_comp_info[0]->last_row_height; |
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95 | } |
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96 | |||
97 | coef->MCU_ctr = 0; |
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98 | coef->MCU_vert_offset = 0; |
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99 | } |
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100 | |||
101 | |||
102 | /* |
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103 | * Initialize for an input processing pass. |
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104 | */ |
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105 | |||
106 | METHODDEF(void) |
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107 | start_input_pass (j_decompress_ptr cinfo) |
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108 | { |
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109 | cinfo->input_iMCU_row = 0; |
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110 | start_iMCU_row(cinfo); |
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111 | } |
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112 | |||
113 | |||
114 | /* |
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115 | * Initialize for an output processing pass. |
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116 | */ |
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117 | |||
118 | METHODDEF(void) |
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119 | start_output_pass (j_decompress_ptr cinfo) |
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120 | { |
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121 | #ifdef BLOCK_SMOOTHING_SUPPORTED |
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122 | my_coef_ptr coef = (my_coef_ptr) cinfo->coef; |
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123 | |||
124 | /* If multipass, check to see whether to use block smoothing on this pass */ |
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125 | if (coef->pub.coef_arrays != NULL) { |
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126 | if (cinfo->do_block_smoothing && smoothing_ok(cinfo)) |
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127 | coef->pub.decompress_data = decompress_smooth_data; |
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128 | else |
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129 | coef->pub.decompress_data = decompress_data; |
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130 | } |
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131 | #endif |
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132 | cinfo->output_iMCU_row = 0; |
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133 | } |
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134 | |||
135 | |||
136 | /* |
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137 | * Decompress and return some data in the single-pass case. |
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138 | * Always attempts to emit one fully interleaved MCU row ("iMCU" row). |
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139 | * Input and output must run in lockstep since we have only a one-MCU buffer. |
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140 | * Return value is JPEG_ROW_COMPLETED, JPEG_SCAN_COMPLETED, or JPEG_SUSPENDED. |
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141 | * |
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142 | * NB: output_buf contains a plane for each component in image, |
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143 | * which we index according to the component's SOF position. |
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144 | */ |
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145 | |||
146 | METHODDEF(int) |
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147 | decompress_onepass (j_decompress_ptr cinfo, JSAMPIMAGE output_buf) |
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148 | { |
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149 | my_coef_ptr coef = (my_coef_ptr) cinfo->coef; |
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150 | JDIMENSION MCU_col_num; /* index of current MCU within row */ |
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151 | JDIMENSION last_MCU_col = cinfo->MCUs_per_row - 1; |
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152 | JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1; |
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153 | int blkn, ci, xindex, yindex, yoffset, useful_width; |
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154 | JSAMPARRAY output_ptr; |
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155 | JDIMENSION start_col, output_col; |
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156 | jpeg_component_info *compptr; |
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157 | inverse_DCT_method_ptr inverse_DCT; |
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158 | |||
159 | /* Loop to process as much as one whole iMCU row */ |
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160 | for (yoffset = coef->MCU_vert_offset; yoffset < coef->MCU_rows_per_iMCU_row; |
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161 | yoffset++) { |
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162 | for (MCU_col_num = coef->MCU_ctr; MCU_col_num <= last_MCU_col; |
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163 | MCU_col_num++) { |
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164 | /* Try to fetch an MCU. Entropy decoder expects buffer to be zeroed. */ |
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165 | jzero_far((void FAR *) coef->MCU_buffer[0], |
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166 | (size_t) (cinfo->blocks_in_MCU * SIZEOF(JBLOCK))); |
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167 | if (! (*cinfo->entropy->decode_mcu) (cinfo, coef->MCU_buffer)) { |
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168 | /* Suspension forced; update state counters and exit */ |
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169 | coef->MCU_vert_offset = yoffset; |
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170 | coef->MCU_ctr = MCU_col_num; |
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171 | return JPEG_SUSPENDED; |
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172 | } |
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173 | /* Determine where data should go in output_buf and do the IDCT thing. |
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174 | * We skip dummy blocks at the right and bottom edges (but blkn gets |
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175 | * incremented past them!). Note the inner loop relies on having |
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176 | * allocated the MCU_buffer[] blocks sequentially. |
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177 | */ |
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178 | blkn = 0; /* index of current DCT block within MCU */ |
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179 | for (ci = 0; ci < cinfo->comps_in_scan; ci++) { |
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180 | compptr = cinfo->cur_comp_info[ci]; |
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181 | /* Don't bother to IDCT an uninteresting component. */ |
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182 | if (! compptr->component_needed) { |
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183 | blkn += compptr->MCU_blocks; |
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184 | continue; |
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185 | } |
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186 | inverse_DCT = cinfo->idct->inverse_DCT[compptr->component_index]; |
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187 | useful_width = (MCU_col_num < last_MCU_col) ? compptr->MCU_width |
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188 | : compptr->last_col_width; |
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189 | output_ptr = output_buf[compptr->component_index] + |
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190 | yoffset * compptr->DCT_scaled_size; |
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191 | start_col = MCU_col_num * compptr->MCU_sample_width; |
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192 | for (yindex = 0; yindex < compptr->MCU_height; yindex++) { |
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193 | if (cinfo->input_iMCU_row < last_iMCU_row || |
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194 | yoffset+yindex < compptr->last_row_height) { |
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195 | output_col = start_col; |
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196 | for (xindex = 0; xindex < useful_width; xindex++) { |
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197 | (*inverse_DCT) (cinfo, compptr, |
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198 | (JCOEFPTR) coef->MCU_buffer[blkn+xindex], |
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199 | output_ptr, output_col); |
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200 | output_col += compptr->DCT_scaled_size; |
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201 | } |
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202 | } |
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203 | blkn += compptr->MCU_width; |
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204 | output_ptr += compptr->DCT_scaled_size; |
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205 | } |
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206 | } |
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207 | } |
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208 | /* Completed an MCU row, but perhaps not an iMCU row */ |
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209 | coef->MCU_ctr = 0; |
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210 | } |
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211 | /* Completed the iMCU row, advance counters for next one */ |
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212 | cinfo->output_iMCU_row++; |
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213 | if (++(cinfo->input_iMCU_row) < cinfo->total_iMCU_rows) { |
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214 | start_iMCU_row(cinfo); |
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215 | return JPEG_ROW_COMPLETED; |
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216 | } |
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217 | /* Completed the scan */ |
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218 | (*cinfo->inputctl->finish_input_pass) (cinfo); |
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219 | return JPEG_SCAN_COMPLETED; |
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220 | } |
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221 | |||
222 | |||
223 | /* |
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224 | * Dummy consume-input routine for single-pass operation. |
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225 | */ |
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226 | |||
227 | METHODDEF(int) |
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228 | dummy_consume_data (j_decompress_ptr cinfo) |
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229 | { |
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230 | return JPEG_SUSPENDED; /* Always indicate nothing was done */ |
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231 | } |
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232 | |||
233 | |||
234 | #ifdef D_MULTISCAN_FILES_SUPPORTED |
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235 | |||
236 | /* |
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237 | * Consume input data and store it in the full-image coefficient buffer. |
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238 | * We read as much as one fully interleaved MCU row ("iMCU" row) per call, |
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239 | * ie, v_samp_factor block rows for each component in the scan. |
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240 | * Return value is JPEG_ROW_COMPLETED, JPEG_SCAN_COMPLETED, or JPEG_SUSPENDED. |
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241 | */ |
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242 | |||
243 | METHODDEF(int) |
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244 | consume_data (j_decompress_ptr cinfo) |
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245 | { |
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246 | my_coef_ptr coef = (my_coef_ptr) cinfo->coef; |
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247 | JDIMENSION MCU_col_num; /* index of current MCU within row */ |
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248 | int blkn, ci, xindex, yindex, yoffset; |
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249 | JDIMENSION start_col; |
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250 | JBLOCKARRAY buffer[MAX_COMPS_IN_SCAN]; |
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251 | JBLOCKROW buffer_ptr; |
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252 | jpeg_component_info *compptr; |
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253 | |||
254 | /* Align the virtual buffers for the components used in this scan. */ |
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255 | for (ci = 0; ci < cinfo->comps_in_scan; ci++) { |
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256 | compptr = cinfo->cur_comp_info[ci]; |
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257 | buffer[ci] = (*cinfo->mem->access_virt_barray) |
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258 | ((j_common_ptr) cinfo, coef->whole_image[compptr->component_index], |
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259 | cinfo->input_iMCU_row * compptr->v_samp_factor, |
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260 | (JDIMENSION) compptr->v_samp_factor, TRUE); |
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261 | /* Note: entropy decoder expects buffer to be zeroed, |
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262 | * but this is handled automatically by the memory manager |
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263 | * because we requested a pre-zeroed array. |
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264 | */ |
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265 | } |
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266 | |||
267 | /* Loop to process one whole iMCU row */ |
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268 | for (yoffset = coef->MCU_vert_offset; yoffset < coef->MCU_rows_per_iMCU_row; |
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269 | yoffset++) { |
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270 | for (MCU_col_num = coef->MCU_ctr; MCU_col_num < cinfo->MCUs_per_row; |
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271 | MCU_col_num++) { |
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272 | /* Construct list of pointers to DCT blocks belonging to this MCU */ |
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273 | blkn = 0; /* index of current DCT block within MCU */ |
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274 | for (ci = 0; ci < cinfo->comps_in_scan; ci++) { |
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275 | compptr = cinfo->cur_comp_info[ci]; |
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276 | start_col = MCU_col_num * compptr->MCU_width; |
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277 | for (yindex = 0; yindex < compptr->MCU_height; yindex++) { |
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278 | buffer_ptr = buffer[ci][yindex+yoffset] + start_col; |
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279 | for (xindex = 0; xindex < compptr->MCU_width; xindex++) { |
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280 | coef->MCU_buffer[blkn++] = buffer_ptr++; |
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281 | } |
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282 | } |
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283 | } |
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284 | /* Try to fetch the MCU. */ |
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285 | if (! (*cinfo->entropy->decode_mcu) (cinfo, coef->MCU_buffer)) { |
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286 | /* Suspension forced; update state counters and exit */ |
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287 | coef->MCU_vert_offset = yoffset; |
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288 | coef->MCU_ctr = MCU_col_num; |
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289 | return JPEG_SUSPENDED; |
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290 | } |
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291 | } |
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292 | /* Completed an MCU row, but perhaps not an iMCU row */ |
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293 | coef->MCU_ctr = 0; |
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294 | } |
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295 | /* Completed the iMCU row, advance counters for next one */ |
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296 | if (++(cinfo->input_iMCU_row) < cinfo->total_iMCU_rows) { |
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297 | start_iMCU_row(cinfo); |
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298 | return JPEG_ROW_COMPLETED; |
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299 | } |
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300 | /* Completed the scan */ |
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301 | (*cinfo->inputctl->finish_input_pass) (cinfo); |
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302 | return JPEG_SCAN_COMPLETED; |
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303 | } |
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304 | |||
305 | |||
306 | /* |
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307 | * Decompress and return some data in the multi-pass case. |
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308 | * Always attempts to emit one fully interleaved MCU row ("iMCU" row). |
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309 | * Return value is JPEG_ROW_COMPLETED, JPEG_SCAN_COMPLETED, or JPEG_SUSPENDED. |
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310 | * |
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311 | * NB: output_buf contains a plane for each component in image. |
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312 | */ |
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313 | |||
314 | METHODDEF(int) |
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315 | decompress_data (j_decompress_ptr cinfo, JSAMPIMAGE output_buf) |
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316 | { |
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317 | my_coef_ptr coef = (my_coef_ptr) cinfo->coef; |
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318 | JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1; |
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319 | JDIMENSION block_num; |
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320 | int ci, block_row, block_rows; |
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321 | JBLOCKARRAY buffer; |
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322 | JBLOCKROW buffer_ptr; |
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323 | JSAMPARRAY output_ptr; |
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324 | JDIMENSION output_col; |
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325 | jpeg_component_info *compptr; |
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326 | inverse_DCT_method_ptr inverse_DCT; |
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327 | |||
328 | /* Force some input to be done if we are getting ahead of the input. */ |
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329 | while (cinfo->input_scan_number < cinfo->output_scan_number || |
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330 | (cinfo->input_scan_number == cinfo->output_scan_number && |
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331 | cinfo->input_iMCU_row <= cinfo->output_iMCU_row)) { |
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332 | if ((*cinfo->inputctl->consume_input)(cinfo) == JPEG_SUSPENDED) |
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333 | return JPEG_SUSPENDED; |
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334 | } |
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335 | |||
336 | /* OK, output from the virtual arrays. */ |
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337 | for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; |
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338 | ci++, compptr++) { |
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339 | /* Don't bother to IDCT an uninteresting component. */ |
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340 | if (! compptr->component_needed) |
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341 | continue; |
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342 | /* Align the virtual buffer for this component. */ |
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343 | buffer = (*cinfo->mem->access_virt_barray) |
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344 | ((j_common_ptr) cinfo, coef->whole_image[ci], |
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345 | cinfo->output_iMCU_row * compptr->v_samp_factor, |
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346 | (JDIMENSION) compptr->v_samp_factor, FALSE); |
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347 | /* Count non-dummy DCT block rows in this iMCU row. */ |
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348 | if (cinfo->output_iMCU_row < last_iMCU_row) |
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349 | block_rows = compptr->v_samp_factor; |
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350 | else { |
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351 | /* NB: can't use last_row_height here; it is input-side-dependent! */ |
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352 | block_rows = (int) (compptr->height_in_blocks % compptr->v_samp_factor); |
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353 | if (block_rows == 0) block_rows = compptr->v_samp_factor; |
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354 | } |
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355 | inverse_DCT = cinfo->idct->inverse_DCT[ci]; |
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356 | output_ptr = output_buf[ci]; |
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357 | /* Loop over all DCT blocks to be processed. */ |
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358 | for (block_row = 0; block_row < block_rows; block_row++) { |
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359 | buffer_ptr = buffer[block_row]; |
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360 | output_col = 0; |
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361 | for (block_num = 0; block_num < compptr->width_in_blocks; block_num++) { |
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362 | (*inverse_DCT) (cinfo, compptr, (JCOEFPTR) buffer_ptr, |
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363 | output_ptr, output_col); |
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364 | buffer_ptr++; |
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365 | output_col += compptr->DCT_scaled_size; |
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366 | } |
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367 | output_ptr += compptr->DCT_scaled_size; |
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368 | } |
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369 | } |
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370 | |||
371 | if (++(cinfo->output_iMCU_row) < cinfo->total_iMCU_rows) |
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372 | return JPEG_ROW_COMPLETED; |
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373 | return JPEG_SCAN_COMPLETED; |
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374 | } |
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375 | |||
376 | #endif /* D_MULTISCAN_FILES_SUPPORTED */ |
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377 | |||
378 | |||
379 | #ifdef BLOCK_SMOOTHING_SUPPORTED |
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380 | |||
381 | /* |
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382 | * This code applies interblock smoothing as described by section K.8 |
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383 | * of the JPEG standard: the first 5 AC coefficients are estimated from |
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384 | * the DC values of a DCT block and its 8 neighboring blocks. |
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385 | * We apply smoothing only for progressive JPEG decoding, and only if |
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386 | * the coefficients it can estimate are not yet known to full precision. |
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387 | */ |
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388 | |||
389 | /* Natural-order array positions of the first 5 zigzag-order coefficients */ |
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390 | #define Q01_POS 1 |
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391 | #define Q10_POS 8 |
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392 | #define Q20_POS 16 |
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393 | #define Q11_POS 9 |
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394 | #define Q02_POS 2 |
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395 | |||
396 | /* |
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397 | * Determine whether block smoothing is applicable and safe. |
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398 | * We also latch the current states of the coef_bits[] entries for the |
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399 | * AC coefficients; otherwise, if the input side of the decompressor |
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400 | * advances into a new scan, we might think the coefficients are known |
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401 | * more accurately than they really are. |
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402 | */ |
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403 | |||
404 | LOCAL(boolean) |
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405 | smoothing_ok (j_decompress_ptr cinfo) |
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406 | { |
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407 | my_coef_ptr coef = (my_coef_ptr) cinfo->coef; |
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408 | boolean smoothing_useful = FALSE; |
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409 | int ci, coefi; |
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410 | jpeg_component_info *compptr; |
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411 | JQUANT_TBL * qtable; |
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412 | int * coef_bits; |
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413 | int * coef_bits_latch; |
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414 | |||
415 | if (! cinfo->progressive_mode || cinfo->coef_bits == NULL) |
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416 | return FALSE; |
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417 | |||
418 | /* Allocate latch area if not already done */ |
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419 | if (coef->coef_bits_latch == NULL) |
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420 | coef->coef_bits_latch = (int *) |
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421 | (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, |
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422 | cinfo->num_components * |
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423 | (SAVED_COEFS * SIZEOF(int))); |
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424 | coef_bits_latch = coef->coef_bits_latch; |
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425 | |||
426 | for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; |
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427 | ci++, compptr++) { |
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428 | /* All components' quantization values must already be latched. */ |
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429 | if ((qtable = compptr->quant_table) == NULL) |
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430 | return FALSE; |
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431 | /* Verify DC & first 5 AC quantizers are nonzero to avoid zero-divide. */ |
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432 | if (qtable->quantval[0] == 0 || |
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433 | qtable->quantval[Q01_POS] == 0 || |
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434 | qtable->quantval[Q10_POS] == 0 || |
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435 | qtable->quantval[Q20_POS] == 0 || |
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436 | qtable->quantval[Q11_POS] == 0 || |
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437 | qtable->quantval[Q02_POS] == 0) |
||
438 | return FALSE; |
||
439 | /* DC values must be at least partly known for all components. */ |
||
440 | coef_bits = cinfo->coef_bits[ci]; |
||
441 | if (coef_bits[0] < 0) |
||
442 | return FALSE; |
||
443 | /* Block smoothing is helpful if some AC coefficients remain inaccurate. */ |
||
444 | for (coefi = 1; coefi <= 5; coefi++) { |
||
445 | coef_bits_latch[coefi] = coef_bits[coefi]; |
||
446 | if (coef_bits[coefi] != 0) |
||
447 | smoothing_useful = TRUE; |
||
448 | } |
||
449 | coef_bits_latch += SAVED_COEFS; |
||
450 | } |
||
451 | |||
452 | return smoothing_useful; |
||
453 | } |
||
454 | |||
455 | |||
456 | /* |
||
457 | * Variant of decompress_data for use when doing block smoothing. |
||
458 | */ |
||
459 | |||
460 | METHODDEF(int) |
||
461 | decompress_smooth_data (j_decompress_ptr cinfo, JSAMPIMAGE output_buf) |
||
462 | { |
||
463 | my_coef_ptr coef = (my_coef_ptr) cinfo->coef; |
||
464 | JDIMENSION last_iMCU_row = cinfo->total_iMCU_rows - 1; |
||
465 | JDIMENSION block_num, last_block_column; |
||
466 | int ci, block_row, block_rows, access_rows; |
||
467 | JBLOCKARRAY buffer; |
||
468 | JBLOCKROW buffer_ptr, prev_block_row, next_block_row; |
||
469 | JSAMPARRAY output_ptr; |
||
470 | JDIMENSION output_col; |
||
471 | jpeg_component_info *compptr; |
||
472 | inverse_DCT_method_ptr inverse_DCT; |
||
473 | boolean first_row, last_row; |
||
474 | JBLOCK workspace; |
||
475 | int *coef_bits; |
||
476 | JQUANT_TBL *quanttbl; |
||
477 | INT32 Q00,Q01,Q02,Q10,Q11,Q20, num; |
||
478 | int DC1,DC2,DC3,DC4,DC5,DC6,DC7,DC8,DC9; |
||
479 | int Al, pred; |
||
480 | |||
481 | /* Force some input to be done if we are getting ahead of the input. */ |
||
482 | while (cinfo->input_scan_number <= cinfo->output_scan_number && |
||
483 | ! cinfo->inputctl->eoi_reached) { |
||
484 | if (cinfo->input_scan_number == cinfo->output_scan_number) { |
||
485 | /* If input is working on current scan, we ordinarily want it to |
||
486 | * have completed the current row. But if input scan is DC, |
||
487 | * we want it to keep one row ahead so that next block row's DC |
||
488 | * values are up to date. |
||
489 | */ |
||
490 | JDIMENSION delta = (cinfo->Ss == 0) ? 1 : 0; |
||
491 | if (cinfo->input_iMCU_row > cinfo->output_iMCU_row+delta) |
||
492 | break; |
||
493 | } |
||
494 | if ((*cinfo->inputctl->consume_input)(cinfo) == JPEG_SUSPENDED) |
||
495 | return JPEG_SUSPENDED; |
||
496 | } |
||
497 | |||
498 | /* OK, output from the virtual arrays. */ |
||
499 | for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; |
||
500 | ci++, compptr++) { |
||
501 | /* Don't bother to IDCT an uninteresting component. */ |
||
502 | if (! compptr->component_needed) |
||
503 | continue; |
||
504 | /* Count non-dummy DCT block rows in this iMCU row. */ |
||
505 | if (cinfo->output_iMCU_row < last_iMCU_row) { |
||
506 | block_rows = compptr->v_samp_factor; |
||
507 | access_rows = block_rows * 2; /* this and next iMCU row */ |
||
508 | last_row = FALSE; |
||
509 | } else { |
||
510 | /* NB: can't use last_row_height here; it is input-side-dependent! */ |
||
511 | block_rows = (int) (compptr->height_in_blocks % compptr->v_samp_factor); |
||
512 | if (block_rows == 0) block_rows = compptr->v_samp_factor; |
||
513 | access_rows = block_rows; /* this iMCU row only */ |
||
514 | last_row = TRUE; |
||
515 | } |
||
516 | /* Align the virtual buffer for this component. */ |
||
517 | if (cinfo->output_iMCU_row > 0) { |
||
518 | access_rows += compptr->v_samp_factor; /* prior iMCU row too */ |
||
519 | buffer = (*cinfo->mem->access_virt_barray) |
||
520 | ((j_common_ptr) cinfo, coef->whole_image[ci], |
||
521 | (cinfo->output_iMCU_row - 1) * compptr->v_samp_factor, |
||
522 | (JDIMENSION) access_rows, FALSE); |
||
523 | buffer += compptr->v_samp_factor; /* point to current iMCU row */ |
||
524 | first_row = FALSE; |
||
525 | } else { |
||
526 | buffer = (*cinfo->mem->access_virt_barray) |
||
527 | ((j_common_ptr) cinfo, coef->whole_image[ci], |
||
528 | (JDIMENSION) 0, (JDIMENSION) access_rows, FALSE); |
||
529 | first_row = TRUE; |
||
530 | } |
||
531 | /* Fetch component-dependent info */ |
||
532 | coef_bits = coef->coef_bits_latch + (ci * SAVED_COEFS); |
||
533 | quanttbl = compptr->quant_table; |
||
534 | Q00 = quanttbl->quantval[0]; |
||
535 | Q01 = quanttbl->quantval[Q01_POS]; |
||
536 | Q10 = quanttbl->quantval[Q10_POS]; |
||
537 | Q20 = quanttbl->quantval[Q20_POS]; |
||
538 | Q11 = quanttbl->quantval[Q11_POS]; |
||
539 | Q02 = quanttbl->quantval[Q02_POS]; |
||
540 | inverse_DCT = cinfo->idct->inverse_DCT[ci]; |
||
541 | output_ptr = output_buf[ci]; |
||
542 | /* Loop over all DCT blocks to be processed. */ |
||
543 | for (block_row = 0; block_row < block_rows; block_row++) { |
||
544 | buffer_ptr = buffer[block_row]; |
||
545 | if (first_row && block_row == 0) |
||
546 | prev_block_row = buffer_ptr; |
||
547 | else |
||
548 | prev_block_row = buffer[block_row-1]; |
||
549 | if (last_row && block_row == block_rows-1) |
||
550 | next_block_row = buffer_ptr; |
||
551 | else |
||
552 | next_block_row = buffer[block_row+1]; |
||
553 | /* We fetch the surrounding DC values using a sliding-register approach. |
||
554 | * Initialize all nine here so as to do the right thing on narrow pics. |
||
555 | */ |
||
556 | DC1 = DC2 = DC3 = (int) prev_block_row[0][0]; |
||
557 | DC4 = DC5 = DC6 = (int) buffer_ptr[0][0]; |
||
558 | DC7 = DC8 = DC9 = (int) next_block_row[0][0]; |
||
559 | output_col = 0; |
||
560 | last_block_column = compptr->width_in_blocks - 1; |
||
561 | for (block_num = 0; block_num <= last_block_column; block_num++) { |
||
562 | /* Fetch current DCT block into workspace so we can modify it. */ |
||
563 | jcopy_block_row(buffer_ptr, (JBLOCKROW) workspace, (JDIMENSION) 1); |
||
564 | /* Update DC values */ |
||
565 | if (block_num < last_block_column) { |
||
566 | DC3 = (int) prev_block_row[1][0]; |
||
567 | DC6 = (int) buffer_ptr[1][0]; |
||
568 | DC9 = (int) next_block_row[1][0]; |
||
569 | } |
||
570 | /* Compute coefficient estimates per K.8. |
||
571 | * An estimate is applied only if coefficient is still zero, |
||
572 | * and is not known to be fully accurate. |
||
573 | */ |
||
574 | /* AC01 */ |
||
575 | if ((Al=coef_bits[1]) != 0 && workspace[1] == 0) { |
||
576 | num = 36 * Q00 * (DC4 - DC6); |
||
577 | if (num >= 0) { |
||
578 | pred = (int) (((Q01<<7) + num) / (Q01<<8)); |
||
579 | if (Al > 0 && pred >= (1< |
||
580 | pred = (1< |
||
581 | } else { |
||
582 | pred = (int) (((Q01<<7) - num) / (Q01<<8)); |
||
583 | if (Al > 0 && pred >= (1< |
||
584 | pred = (1< |
||
585 | pred = -pred; |
||
586 | } |
||
587 | workspace[1] = (JCOEF) pred; |
||
588 | } |
||
589 | /* AC10 */ |
||
590 | if ((Al=coef_bits[2]) != 0 && workspace[8] == 0) { |
||
591 | num = 36 * Q00 * (DC2 - DC8); |
||
592 | if (num >= 0) { |
||
593 | pred = (int) (((Q10<<7) + num) / (Q10<<8)); |
||
594 | if (Al > 0 && pred >= (1< |
||
595 | pred = (1< |
||
596 | } else { |
||
597 | pred = (int) (((Q10<<7) - num) / (Q10<<8)); |
||
598 | if (Al > 0 && pred >= (1< |
||
599 | pred = (1< |
||
600 | pred = -pred; |
||
601 | } |
||
602 | workspace[8] = (JCOEF) pred; |
||
603 | } |
||
604 | /* AC20 */ |
||
605 | if ((Al=coef_bits[3]) != 0 && workspace[16] == 0) { |
||
606 | num = 9 * Q00 * (DC2 + DC8 - 2*DC5); |
||
607 | if (num >= 0) { |
||
608 | pred = (int) (((Q20<<7) + num) / (Q20<<8)); |
||
609 | if (Al > 0 && pred >= (1< |
||
610 | pred = (1< |
||
611 | } else { |
||
612 | pred = (int) (((Q20<<7) - num) / (Q20<<8)); |
||
613 | if (Al > 0 && pred >= (1< |
||
614 | pred = (1< |
||
615 | pred = -pred; |
||
616 | } |
||
617 | workspace[16] = (JCOEF) pred; |
||
618 | } |
||
619 | /* AC11 */ |
||
620 | if ((Al=coef_bits[4]) != 0 && workspace[9] == 0) { |
||
621 | num = 5 * Q00 * (DC1 - DC3 - DC7 + DC9); |
||
622 | if (num >= 0) { |
||
623 | pred = (int) (((Q11<<7) + num) / (Q11<<8)); |
||
624 | if (Al > 0 && pred >= (1< |
||
625 | pred = (1< |
||
626 | } else { |
||
627 | pred = (int) (((Q11<<7) - num) / (Q11<<8)); |
||
628 | if (Al > 0 && pred >= (1< |
||
629 | pred = (1< |
||
630 | pred = -pred; |
||
631 | } |
||
632 | workspace[9] = (JCOEF) pred; |
||
633 | } |
||
634 | /* AC02 */ |
||
635 | if ((Al=coef_bits[5]) != 0 && workspace[2] == 0) { |
||
636 | num = 9 * Q00 * (DC4 + DC6 - 2*DC5); |
||
637 | if (num >= 0) { |
||
638 | pred = (int) (((Q02<<7) + num) / (Q02<<8)); |
||
639 | if (Al > 0 && pred >= (1< |
||
640 | pred = (1< |
||
641 | } else { |
||
642 | pred = (int) (((Q02<<7) - num) / (Q02<<8)); |
||
643 | if (Al > 0 && pred >= (1< |
||
644 | pred = (1< |
||
645 | pred = -pred; |
||
646 | } |
||
647 | workspace[2] = (JCOEF) pred; |
||
648 | } |
||
649 | /* OK, do the IDCT */ |
||
650 | (*inverse_DCT) (cinfo, compptr, (JCOEFPTR) workspace, |
||
651 | output_ptr, output_col); |
||
652 | /* Advance for next column */ |
||
653 | DC1 = DC2; DC2 = DC3; |
||
654 | DC4 = DC5; DC5 = DC6; |
||
655 | DC7 = DC8; DC8 = DC9; |
||
656 | buffer_ptr++, prev_block_row++, next_block_row++; |
||
657 | output_col += compptr->DCT_scaled_size; |
||
658 | } |
||
659 | output_ptr += compptr->DCT_scaled_size; |
||
660 | } |
||
661 | } |
||
662 | |||
663 | if (++(cinfo->output_iMCU_row) < cinfo->total_iMCU_rows) |
||
664 | return JPEG_ROW_COMPLETED; |
||
665 | return JPEG_SCAN_COMPLETED; |
||
666 | } |
||
667 | |||
668 | #endif /* BLOCK_SMOOTHING_SUPPORTED */ |
||
669 | |||
670 | |||
671 | /* |
||
672 | * Initialize coefficient buffer controller. |
||
673 | */ |
||
674 | |||
675 | GLOBAL(void) |
||
676 | jinit_d_coef_controller (j_decompress_ptr cinfo, boolean need_full_buffer) |
||
677 | { |
||
678 | my_coef_ptr coef; |
||
679 | |||
680 | coef = (my_coef_ptr) |
||
681 | (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, |
||
682 | SIZEOF(my_coef_controller)); |
||
683 | cinfo->coef = (struct jpeg_d_coef_controller *) coef; |
||
684 | coef->pub.start_input_pass = start_input_pass; |
||
685 | coef->pub.start_output_pass = start_output_pass; |
||
686 | #ifdef BLOCK_SMOOTHING_SUPPORTED |
||
687 | coef->coef_bits_latch = NULL; |
||
688 | #endif |
||
689 | |||
690 | /* Create the coefficient buffer. */ |
||
691 | if (need_full_buffer) { |
||
692 | #ifdef D_MULTISCAN_FILES_SUPPORTED |
||
693 | /* Allocate a full-image virtual array for each component, */ |
||
694 | /* padded to a multiple of samp_factor DCT blocks in each direction. */ |
||
695 | /* Note we ask for a pre-zeroed array. */ |
||
696 | int ci, access_rows; |
||
697 | jpeg_component_info *compptr; |
||
698 | |||
699 | for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; |
||
700 | ci++, compptr++) { |
||
701 | access_rows = compptr->v_samp_factor; |
||
702 | #ifdef BLOCK_SMOOTHING_SUPPORTED |
||
703 | /* If block smoothing could be used, need a bigger window */ |
||
704 | if (cinfo->progressive_mode) |
||
705 | access_rows *= 3; |
||
706 | #endif |
||
707 | coef->whole_image[ci] = (*cinfo->mem->request_virt_barray) |
||
708 | ((j_common_ptr) cinfo, JPOOL_IMAGE, TRUE, |
||
709 | (JDIMENSION) jround_up((long) compptr->width_in_blocks, |
||
710 | (long) compptr->h_samp_factor), |
||
711 | (JDIMENSION) jround_up((long) compptr->height_in_blocks, |
||
712 | (long) compptr->v_samp_factor), |
||
713 | (JDIMENSION) access_rows); |
||
714 | } |
||
715 | coef->pub.consume_data = consume_data; |
||
716 | coef->pub.decompress_data = decompress_data; |
||
717 | coef->pub.coef_arrays = coef->whole_image; /* link to virtual arrays */ |
||
718 | #else |
||
719 | ERREXIT(cinfo, JERR_NOT_COMPILED); |
||
720 | #endif |
||
721 | } else { |
||
722 | /* We only need a single-MCU buffer. */ |
||
723 | JBLOCKROW buffer; |
||
724 | int i; |
||
725 | |||
726 | buffer = (JBLOCKROW) |
||
727 | (*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE, |
||
728 | D_MAX_BLOCKS_IN_MCU * SIZEOF(JBLOCK)); |
||
729 | for (i = 0; i < D_MAX_BLOCKS_IN_MCU; i++) { |
||
730 | coef->MCU_buffer[i] = buffer + i; |
||
731 | } |
||
732 | coef->pub.consume_data = dummy_consume_data; |
||
733 | coef->pub.decompress_data = decompress_onepass; |
||
734 | coef->pub.coef_arrays = NULL; /* flag for no virtual arrays */ |
||
735 | } |
||
736 | }>>> |