1 #if !defined(_FX_JPEG_TURBO_) 2 /* 3 * jdpostct.c 4 * 5 * Copyright (C) 1994-1996, Thomas G. Lane. 6 * This file is part of the Independent JPEG Group's software. 7 * For conditions of distribution and use, see the accompanying README file. 8 * 9 * This file contains the decompression postprocessing controller. 10 * This controller manages the upsampling, color conversion, and color 11 * quantization/reduction steps; specifically, it controls the buffering 12 * between upsample/color conversion and color quantization/reduction. 13 * 14 * If no color quantization/reduction is required, then this module has no 15 * work to do, and it just hands off to the upsample/color conversion code. 16 * An integrated upsample/convert/quantize process would replace this module 17 * entirely. 18 */ 19 20 #define JPEG_INTERNALS 21 #include "jinclude.h" 22 #include "jpeglib.h" 23 24 25 /* Private buffer controller object */ 26 27 typedef struct { 28 struct jpeg_d_post_controller pub; /* public fields */ 29 30 /* Color quantization source buffer: this holds output data from 31 * the upsample/color conversion step to be passed to the quantizer. 32 * For two-pass color quantization, we need a full-image buffer; 33 * for one-pass operation, a strip buffer is sufficient. 34 */ 35 jvirt_sarray_ptr whole_image; /* virtual array, or NULL if one-pass */ 36 JSAMPARRAY buffer; /* strip buffer, or current strip of virtual */ 37 JDIMENSION strip_height; /* buffer size in rows */ 38 /* for two-pass mode only: */ 39 JDIMENSION starting_row; /* row # of first row in current strip */ 40 JDIMENSION next_row; /* index of next row to fill/empty in strip */ 41 } my_post_controller; 42 43 typedef my_post_controller * my_post_ptr; 44 45 46 /* Forward declarations */ 47 METHODDEF(void) post_process_1pass 48 JPP((j_decompress_ptr cinfo, 49 JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr, 50 JDIMENSION in_row_groups_avail, 51 JSAMPARRAY output_buf, JDIMENSION *out_row_ctr, 52 JDIMENSION out_rows_avail)); 53 #ifdef QUANT_2PASS_SUPPORTED 54 METHODDEF(void) post_process_prepass 55 JPP((j_decompress_ptr cinfo, 56 JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr, 57 JDIMENSION in_row_groups_avail, 58 JSAMPARRAY output_buf, JDIMENSION *out_row_ctr, 59 JDIMENSION out_rows_avail)); 60 METHODDEF(void) post_process_2pass 61 JPP((j_decompress_ptr cinfo, 62 JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr, 63 JDIMENSION in_row_groups_avail, 64 JSAMPARRAY output_buf, JDIMENSION *out_row_ctr, 65 JDIMENSION out_rows_avail)); 66 #endif 67 68 69 /* 70 * Initialize for a processing pass. 71 */ 72 73 METHODDEF(void) 74 start_pass_dpost (j_decompress_ptr cinfo, J_BUF_MODE pass_mode) 75 { 76 my_post_ptr post = (my_post_ptr) cinfo->post; 77 78 switch (pass_mode) { 79 case JBUF_PASS_THRU: 80 if (cinfo->quantize_colors) { 81 /* Single-pass processing with color quantization. */ 82 post->pub.post_process_data = post_process_1pass; 83 /* We could be doing buffered-image output before starting a 2-pass 84 * color quantization; in that case, jinit_d_post_controller did not 85 * allocate a strip buffer. Use the virtual-array buffer as workspace. 86 */ 87 if (post->buffer == NULL) { 88 post->buffer = (*cinfo->mem->access_virt_sarray) 89 ((j_common_ptr) cinfo, post->whole_image, 90 (JDIMENSION) 0, post->strip_height, TRUE); 91 } 92 } else { 93 /* For single-pass processing without color quantization, 94 * I have no work to do; just call the upsampler directly. 95 */ 96 post->pub.post_process_data = cinfo->upsample->upsample; 97 } 98 break; 99 #ifdef QUANT_2PASS_SUPPORTED 100 case JBUF_SAVE_AND_PASS: 101 /* First pass of 2-pass quantization */ 102 if (post->whole_image == NULL) 103 ERREXIT(cinfo, JERR_BAD_BUFFER_MODE); 104 post->pub.post_process_data = post_process_prepass; 105 break; 106 case JBUF_CRANK_DEST: 107 /* Second pass of 2-pass quantization */ 108 if (post->whole_image == NULL) 109 ERREXIT(cinfo, JERR_BAD_BUFFER_MODE); 110 post->pub.post_process_data = post_process_2pass; 111 break; 112 #endif /* QUANT_2PASS_SUPPORTED */ 113 default: 114 ERREXIT(cinfo, JERR_BAD_BUFFER_MODE); 115 break; 116 } 117 post->starting_row = post->next_row = 0; 118 } 119 120 121 /* 122 * Process some data in the one-pass (strip buffer) case. 123 * This is used for color precision reduction as well as one-pass quantization. 124 */ 125 126 METHODDEF(void) 127 post_process_1pass (j_decompress_ptr cinfo, 128 JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr, 129 JDIMENSION in_row_groups_avail, 130 JSAMPARRAY output_buf, JDIMENSION *out_row_ctr, 131 JDIMENSION out_rows_avail) 132 { 133 my_post_ptr post = (my_post_ptr) cinfo->post; 134 JDIMENSION num_rows, max_rows; 135 136 /* Fill the buffer, but not more than what we can dump out in one go. */ 137 /* Note we rely on the upsampler to detect bottom of image. */ 138 max_rows = out_rows_avail - *out_row_ctr; 139 if (max_rows > post->strip_height) 140 max_rows = post->strip_height; 141 num_rows = 0; 142 (*cinfo->upsample->upsample) (cinfo, 143 input_buf, in_row_group_ctr, in_row_groups_avail, 144 post->buffer, &num_rows, max_rows); 145 /* Quantize and emit data. */ 146 (*cinfo->cquantize->color_quantize) (cinfo, 147 post->buffer, output_buf + *out_row_ctr, (int) num_rows); 148 *out_row_ctr += num_rows; 149 } 150 151 152 #ifdef QUANT_2PASS_SUPPORTED 153 154 /* 155 * Process some data in the first pass of 2-pass quantization. 156 */ 157 158 METHODDEF(void) 159 post_process_prepass (j_decompress_ptr cinfo, 160 JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr, 161 JDIMENSION in_row_groups_avail, 162 JSAMPARRAY output_buf, JDIMENSION *out_row_ctr, 163 JDIMENSION out_rows_avail) 164 { 165 my_post_ptr post = (my_post_ptr) cinfo->post; 166 JDIMENSION old_next_row, num_rows; 167 168 /* Reposition virtual buffer if at start of strip. */ 169 if (post->next_row == 0) { 170 post->buffer = (*cinfo->mem->access_virt_sarray) 171 ((j_common_ptr) cinfo, post->whole_image, 172 post->starting_row, post->strip_height, TRUE); 173 } 174 175 /* Upsample some data (up to a strip height's worth). */ 176 old_next_row = post->next_row; 177 (*cinfo->upsample->upsample) (cinfo, 178 input_buf, in_row_group_ctr, in_row_groups_avail, 179 post->buffer, &post->next_row, post->strip_height); 180 181 /* Allow quantizer to scan new data. No data is emitted, */ 182 /* but we advance out_row_ctr so outer loop can tell when we're done. */ 183 if (post->next_row > old_next_row) { 184 num_rows = post->next_row - old_next_row; 185 (*cinfo->cquantize->color_quantize) (cinfo, post->buffer + old_next_row, 186 (JSAMPARRAY) NULL, (int) num_rows); 187 *out_row_ctr += num_rows; 188 } 189 190 /* Advance if we filled the strip. */ 191 if (post->next_row >= post->strip_height) { 192 post->starting_row += post->strip_height; 193 post->next_row = 0; 194 } 195 } 196 197 198 /* 199 * Process some data in the second pass of 2-pass quantization. 200 */ 201 202 METHODDEF(void) 203 post_process_2pass (j_decompress_ptr cinfo, 204 JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr, 205 JDIMENSION in_row_groups_avail, 206 JSAMPARRAY output_buf, JDIMENSION *out_row_ctr, 207 JDIMENSION out_rows_avail) 208 { 209 my_post_ptr post = (my_post_ptr) cinfo->post; 210 JDIMENSION num_rows, max_rows; 211 212 /* Reposition virtual buffer if at start of strip. */ 213 if (post->next_row == 0) { 214 post->buffer = (*cinfo->mem->access_virt_sarray) 215 ((j_common_ptr) cinfo, post->whole_image, 216 post->starting_row, post->strip_height, FALSE); 217 } 218 219 /* Determine number of rows to emit. */ 220 num_rows = post->strip_height - post->next_row; /* available in strip */ 221 max_rows = out_rows_avail - *out_row_ctr; /* available in output area */ 222 if (num_rows > max_rows) 223 num_rows = max_rows; 224 /* We have to check bottom of image here, can't depend on upsampler. */ 225 max_rows = cinfo->output_height - post->starting_row; 226 if (num_rows > max_rows) 227 num_rows = max_rows; 228 229 /* Quantize and emit data. */ 230 (*cinfo->cquantize->color_quantize) (cinfo, 231 post->buffer + post->next_row, output_buf + *out_row_ctr, 232 (int) num_rows); 233 *out_row_ctr += num_rows; 234 235 /* Advance if we filled the strip. */ 236 post->next_row += num_rows; 237 if (post->next_row >= post->strip_height) { 238 post->starting_row += post->strip_height; 239 post->next_row = 0; 240 } 241 } 242 243 #endif /* QUANT_2PASS_SUPPORTED */ 244 245 246 /* 247 * Initialize postprocessing controller. 248 */ 249 250 GLOBAL(void) 251 jinit_d_post_controller (j_decompress_ptr cinfo, boolean need_full_buffer) 252 { 253 my_post_ptr post; 254 255 post = (my_post_ptr) 256 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, 257 SIZEOF(my_post_controller)); 258 cinfo->post = (struct jpeg_d_post_controller *) post; 259 post->pub.start_pass = start_pass_dpost; 260 post->whole_image = NULL; /* flag for no virtual arrays */ 261 post->buffer = NULL; /* flag for no strip buffer */ 262 263 /* Create the quantization buffer, if needed */ 264 if (cinfo->quantize_colors) { 265 /* The buffer strip height is max_v_samp_factor, which is typically 266 * an efficient number of rows for upsampling to return. 267 * (In the presence of output rescaling, we might want to be smarter?) 268 */ 269 post->strip_height = (JDIMENSION) cinfo->max_v_samp_factor; 270 if (need_full_buffer) { 271 /* Two-pass color quantization: need full-image storage. */ 272 /* We round up the number of rows to a multiple of the strip height. */ 273 #ifdef QUANT_2PASS_SUPPORTED 274 post->whole_image = (*cinfo->mem->request_virt_sarray) 275 ((j_common_ptr) cinfo, JPOOL_IMAGE, FALSE, 276 cinfo->output_width * cinfo->out_color_components, 277 (JDIMENSION) jround_up((long) cinfo->output_height, 278 (long) post->strip_height), 279 post->strip_height); 280 #else 281 ERREXIT(cinfo, JERR_BAD_BUFFER_MODE); 282 #endif /* QUANT_2PASS_SUPPORTED */ 283 } else { 284 /* One-pass color quantization: just make a strip buffer. */ 285 post->buffer = (*cinfo->mem->alloc_sarray) 286 ((j_common_ptr) cinfo, JPOOL_IMAGE, 287 cinfo->output_width * cinfo->out_color_components, 288 post->strip_height); 289 } 290 } 291 } 292 293 #endif //_FX_JPEG_TURBO_ 294
