1 /* 2 * jcmainct.c 3 * 4 * Copyright (C) 1994-1996, Thomas G. Lane. 5 * Modified 2003-2012 by Guido Vollbeding. 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 main buffer controller for compression. 10 * The main buffer lies between the pre-processor and the JPEG 11 * compressor proper; it holds downsampled data in the JPEG colorspace. 12 */ 13 14 #define JPEG_INTERNALS 15 #include "jinclude.h" 16 #include "jpeglib.h" 17 18 19 /* Note: currently, there is no operating mode in which a full-image buffer 20 * is needed at this step. If there were, that mode could not be used with 21 * "raw data" input, since this module is bypassed in that case. However, 22 * we've left the code here for possible use in special applications. 23 */ 24 #undef FULL_MAIN_BUFFER_SUPPORTED 25 26 27 /* Private buffer controller object */ 28 29 typedef struct { 30 struct jpeg_c_main_controller pub; /* public fields */ 31 32 JDIMENSION cur_iMCU_row; /* number of current iMCU row */ 33 JDIMENSION rowgroup_ctr; /* counts row groups received in iMCU row */ 34 boolean suspended; /* remember if we suspended output */ 35 J_BUF_MODE pass_mode; /* current operating mode */ 36 37 /* If using just a strip buffer, this points to the entire set of buffers 38 * (we allocate one for each component). In the full-image case, this 39 * points to the currently accessible strips of the virtual arrays. 40 */ 41 JSAMPARRAY buffer[MAX_COMPONENTS]; 42 43 #ifdef FULL_MAIN_BUFFER_SUPPORTED 44 /* If using full-image storage, this array holds pointers to virtual-array 45 * control blocks for each component. Unused if not full-image storage. 46 */ 47 jvirt_sarray_ptr whole_image[MAX_COMPONENTS]; 48 #endif 49 } my_main_controller; 50 51 typedef my_main_controller * my_main_ptr; 52 53 54 /* Forward declarations */ 55 METHODDEF(void) process_data_simple_main 56 JPP((j_compress_ptr cinfo, JSAMPARRAY input_buf, 57 JDIMENSION *in_row_ctr, JDIMENSION in_rows_avail)); 58 #ifdef FULL_MAIN_BUFFER_SUPPORTED 59 METHODDEF(void) process_data_buffer_main 60 JPP((j_compress_ptr cinfo, JSAMPARRAY input_buf, 61 JDIMENSION *in_row_ctr, JDIMENSION in_rows_avail)); 62 #endif 63 64 65 /* 66 * Initialize for a processing pass. 67 */ 68 69 METHODDEF(void) 70 start_pass_main (j_compress_ptr cinfo, J_BUF_MODE pass_mode) 71 { 72 my_main_ptr mainp = (my_main_ptr) cinfo->main; 73 74 /* Do nothing in raw-data mode. */ 75 if (cinfo->raw_data_in) 76 return; 77 78 mainp->cur_iMCU_row = 0; /* initialize counters */ 79 mainp->rowgroup_ctr = 0; 80 mainp->suspended = FALSE; 81 mainp->pass_mode = pass_mode; /* save mode for use by process_data */ 82 83 switch (pass_mode) { 84 case JBUF_PASS_THRU: 85 #ifdef FULL_MAIN_BUFFER_SUPPORTED 86 if (mainp->whole_image[0] != NULL) 87 ERREXIT(cinfo, JERR_BAD_BUFFER_MODE); 88 #endif 89 mainp->pub.process_data = process_data_simple_main; 90 break; 91 #ifdef FULL_MAIN_BUFFER_SUPPORTED 92 case JBUF_SAVE_SOURCE: 93 case JBUF_CRANK_DEST: 94 case JBUF_SAVE_AND_PASS: 95 if (mainp->whole_image[0] == NULL) 96 ERREXIT(cinfo, JERR_BAD_BUFFER_MODE); 97 mainp->pub.process_data = process_data_buffer_main; 98 break; 99 #endif 100 default: 101 ERREXIT(cinfo, JERR_BAD_BUFFER_MODE); 102 break; 103 } 104 } 105 106 107 /* 108 * Process some data. 109 * This routine handles the simple pass-through mode, 110 * where we have only a strip buffer. 111 */ 112 113 METHODDEF(void) 114 process_data_simple_main (j_compress_ptr cinfo, 115 JSAMPARRAY input_buf, JDIMENSION *in_row_ctr, 116 JDIMENSION in_rows_avail) 117 { 118 my_main_ptr mainp = (my_main_ptr) cinfo->main; 119 120 while (mainp->cur_iMCU_row < cinfo->total_iMCU_rows) { 121 /* Read input data if we haven't filled the main buffer yet */ 122 if (mainp->rowgroup_ctr < (JDIMENSION) cinfo->min_DCT_v_scaled_size) 123 (*cinfo->prep->pre_process_data) (cinfo, 124 input_buf, in_row_ctr, in_rows_avail, 125 mainp->buffer, &mainp->rowgroup_ctr, 126 (JDIMENSION) cinfo->min_DCT_v_scaled_size); 127 128 /* If we don't have a full iMCU row buffered, return to application for 129 * more data. Note that preprocessor will always pad to fill the iMCU row 130 * at the bottom of the image. 131 */ 132 if (mainp->rowgroup_ctr != (JDIMENSION) cinfo->min_DCT_v_scaled_size) 133 return; 134 135 /* Send the completed row to the compressor */ 136 if (! (*cinfo->coef->compress_data) (cinfo, mainp->buffer)) { 137 /* If compressor did not consume the whole row, then we must need to 138 * suspend processing and return to the application. In this situation 139 * we pretend we didn't yet consume the last input row; otherwise, if 140 * it happened to be the last row of the image, the application would 141 * think we were done. 142 */ 143 if (! mainp->suspended) { 144 (*in_row_ctr)--; 145 mainp->suspended = TRUE; 146 } 147 return; 148 } 149 /* We did finish the row. Undo our little suspension hack if a previous 150 * call suspended; then mark the main buffer empty. 151 */ 152 if (mainp->suspended) { 153 (*in_row_ctr)++; 154 mainp->suspended = FALSE; 155 } 156 mainp->rowgroup_ctr = 0; 157 mainp->cur_iMCU_row++; 158 } 159 } 160 161 162 #ifdef FULL_MAIN_BUFFER_SUPPORTED 163 164 /* 165 * Process some data. 166 * This routine handles all of the modes that use a full-size buffer. 167 */ 168 169 METHODDEF(void) 170 process_data_buffer_main (j_compress_ptr cinfo, 171 JSAMPARRAY input_buf, JDIMENSION *in_row_ctr, 172 JDIMENSION in_rows_avail) 173 { 174 my_main_ptr mainp = (my_main_ptr) cinfo->main; 175 int ci; 176 jpeg_component_info *compptr; 177 boolean writing = (mainp->pass_mode != JBUF_CRANK_DEST); 178 179 while (mainp->cur_iMCU_row < cinfo->total_iMCU_rows) { 180 /* Realign the virtual buffers if at the start of an iMCU row. */ 181 if (mainp->rowgroup_ctr == 0) { 182 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; 183 ci++, compptr++) { 184 mainp->buffer[ci] = (*cinfo->mem->access_virt_sarray) 185 ((j_common_ptr) cinfo, mainp->whole_image[ci], mainp->cur_iMCU_row * 186 ((JDIMENSION) (compptr->v_samp_factor * cinfo->min_DCT_v_scaled_size)), 187 (JDIMENSION) (compptr->v_samp_factor * cinfo->min_DCT_v_scaled_size), 188 writing); 189 } 190 /* In a read pass, pretend we just read some source data. */ 191 if (! writing) { 192 *in_row_ctr += (JDIMENSION) 193 (cinfo->max_v_samp_factor * cinfo->min_DCT_v_scaled_size); 194 mainp->rowgroup_ctr = (JDIMENSION) cinfo->min_DCT_v_scaled_size; 195 } 196 } 197 198 /* If a write pass, read input data until the current iMCU row is full. */ 199 /* Note: preprocessor will pad if necessary to fill the last iMCU row. */ 200 if (writing) { 201 (*cinfo->prep->pre_process_data) (cinfo, 202 input_buf, in_row_ctr, in_rows_avail, 203 mainp->buffer, &mainp->rowgroup_ctr, 204 (JDIMENSION) cinfo->min_DCT_v_scaled_size); 205 /* Return to application if we need more data to fill the iMCU row. */ 206 if (mainp->rowgroup_ctr < (JDIMENSION) cinfo->min_DCT_v_scaled_size) 207 return; 208 } 209 210 /* Emit data, unless this is a sink-only pass. */ 211 if (mainp->pass_mode != JBUF_SAVE_SOURCE) { 212 if (! (*cinfo->coef->compress_data) (cinfo, mainp->buffer)) { 213 /* If compressor did not consume the whole row, then we must need to 214 * suspend processing and return to the application. In this situation 215 * we pretend we didn't yet consume the last input row; otherwise, if 216 * it happened to be the last row of the image, the application would 217 * think we were done. 218 */ 219 if (! mainp->suspended) { 220 (*in_row_ctr)--; 221 mainp->suspended = TRUE; 222 } 223 return; 224 } 225 /* We did finish the row. Undo our little suspension hack if a previous 226 * call suspended; then mark the main buffer empty. 227 */ 228 if (mainp->suspended) { 229 (*in_row_ctr)++; 230 mainp->suspended = FALSE; 231 } 232 } 233 234 /* If get here, we are done with this iMCU row. Mark buffer empty. */ 235 mainp->rowgroup_ctr = 0; 236 mainp->cur_iMCU_row++; 237 } 238 } 239 240 #endif /* FULL_MAIN_BUFFER_SUPPORTED */ 241 242 243 /* 244 * Initialize main buffer controller. 245 */ 246 247 GLOBAL(void) 248 jinit_c_main_controller (j_compress_ptr cinfo, boolean need_full_buffer) 249 { 250 my_main_ptr mainp; 251 int ci; 252 jpeg_component_info *compptr; 253 254 mainp = (my_main_ptr) 255 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, 256 SIZEOF(my_main_controller)); 257 cinfo->main = &mainp->pub; 258 mainp->pub.start_pass = start_pass_main; 259 260 /* We don't need to create a buffer in raw-data mode. */ 261 if (cinfo->raw_data_in) 262 return; 263 264 /* Create the buffer. It holds downsampled data, so each component 265 * may be of a different size. 266 */ 267 if (need_full_buffer) { 268 #ifdef FULL_MAIN_BUFFER_SUPPORTED 269 /* Allocate a full-image virtual array for each component */ 270 /* Note we pad the bottom to a multiple of the iMCU height */ 271 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; 272 ci++, compptr++) { 273 mainp->whole_image[ci] = (*cinfo->mem->request_virt_sarray) 274 ((j_common_ptr) cinfo, JPOOL_IMAGE, FALSE, 275 compptr->width_in_blocks * ((JDIMENSION) compptr->DCT_h_scaled_size), 276 ((JDIMENSION) jround_up((long) compptr->height_in_blocks, 277 (long) compptr->v_samp_factor)) * 278 ((JDIMENSION) cinfo->min_DCT_v_scaled_size), 279 (JDIMENSION) (compptr->v_samp_factor * compptr->DCT_v_scaled_size)); 280 } 281 #else 282 ERREXIT(cinfo, JERR_BAD_BUFFER_MODE); 283 #endif 284 } else { 285 #ifdef FULL_MAIN_BUFFER_SUPPORTED 286 mainp->whole_image[0] = NULL; /* flag for no virtual arrays */ 287 #endif 288 /* Allocate a strip buffer for each component */ 289 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; 290 ci++, compptr++) { 291 mainp->buffer[ci] = (*cinfo->mem->alloc_sarray) 292 ((j_common_ptr) cinfo, JPOOL_IMAGE, 293 compptr->width_in_blocks * ((JDIMENSION) compptr->DCT_h_scaled_size), 294 (JDIMENSION) (compptr->v_samp_factor * compptr->DCT_v_scaled_size)); 295 } 296 } 297 } 298
