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annotate libs/libjpeg/jcmainct.c @ 35:643f4ab609a4

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added readme and license
author John Tsiombikas <nuclear@member.fsf.org>
date Sat, 31 Oct 2015 05:45:35 +0200
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nuclear@2 1 /*
nuclear@2 2 * jcmainct.c
nuclear@2 3 *
nuclear@2 4 * Copyright (C) 1994-1996, Thomas G. Lane.
nuclear@2 5 * This file is part of the Independent JPEG Group's software.
nuclear@2 6 * For conditions of distribution and use, see the accompanying README file.
nuclear@2 7 *
nuclear@2 8 * This file contains the main buffer controller for compression.
nuclear@2 9 * The main buffer lies between the pre-processor and the JPEG
nuclear@2 10 * compressor proper; it holds downsampled data in the JPEG colorspace.
nuclear@2 11 */
nuclear@2 12
nuclear@2 13 #define JPEG_INTERNALS
nuclear@2 14 #include "jinclude.h"
nuclear@2 15 #include "jpeglib.h"
nuclear@2 16
nuclear@2 17
nuclear@2 18 /* Note: currently, there is no operating mode in which a full-image buffer
nuclear@2 19 * is needed at this step. If there were, that mode could not be used with
nuclear@2 20 * "raw data" input, since this module is bypassed in that case. However,
nuclear@2 21 * we've left the code here for possible use in special applications.
nuclear@2 22 */
nuclear@2 23 #undef FULL_MAIN_BUFFER_SUPPORTED
nuclear@2 24
nuclear@2 25
nuclear@2 26 /* Private buffer controller object */
nuclear@2 27
nuclear@2 28 typedef struct {
nuclear@2 29 struct jpeg_c_main_controller pub; /* public fields */
nuclear@2 30
nuclear@2 31 JDIMENSION cur_iMCU_row; /* number of current iMCU row */
nuclear@2 32 JDIMENSION rowgroup_ctr; /* counts row groups received in iMCU row */
nuclear@2 33 boolean suspended; /* remember if we suspended output */
nuclear@2 34 J_BUF_MODE pass_mode; /* current operating mode */
nuclear@2 35
nuclear@2 36 /* If using just a strip buffer, this points to the entire set of buffers
nuclear@2 37 * (we allocate one for each component). In the full-image case, this
nuclear@2 38 * points to the currently accessible strips of the virtual arrays.
nuclear@2 39 */
nuclear@2 40 JSAMPARRAY buffer[MAX_COMPONENTS];
nuclear@2 41
nuclear@2 42 #ifdef FULL_MAIN_BUFFER_SUPPORTED
nuclear@2 43 /* If using full-image storage, this array holds pointers to virtual-array
nuclear@2 44 * control blocks for each component. Unused if not full-image storage.
nuclear@2 45 */
nuclear@2 46 jvirt_sarray_ptr whole_image[MAX_COMPONENTS];
nuclear@2 47 #endif
nuclear@2 48 } my_main_controller;
nuclear@2 49
nuclear@2 50 typedef my_main_controller * my_main_ptr;
nuclear@2 51
nuclear@2 52
nuclear@2 53 /* Forward declarations */
nuclear@2 54 METHODDEF(void) process_data_simple_main
nuclear@2 55 JPP((j_compress_ptr cinfo, JSAMPARRAY input_buf,
nuclear@2 56 JDIMENSION *in_row_ctr, JDIMENSION in_rows_avail));
nuclear@2 57 #ifdef FULL_MAIN_BUFFER_SUPPORTED
nuclear@2 58 METHODDEF(void) process_data_buffer_main
nuclear@2 59 JPP((j_compress_ptr cinfo, JSAMPARRAY input_buf,
nuclear@2 60 JDIMENSION *in_row_ctr, JDIMENSION in_rows_avail));
nuclear@2 61 #endif
nuclear@2 62
nuclear@2 63
nuclear@2 64 /*
nuclear@2 65 * Initialize for a processing pass.
nuclear@2 66 */
nuclear@2 67
nuclear@2 68 METHODDEF(void)
nuclear@2 69 start_pass_main (j_compress_ptr cinfo, J_BUF_MODE pass_mode)
nuclear@2 70 {
nuclear@2 71 my_main_ptr main = (my_main_ptr) cinfo->main;
nuclear@2 72
nuclear@2 73 /* Do nothing in raw-data mode. */
nuclear@2 74 if (cinfo->raw_data_in)
nuclear@2 75 return;
nuclear@2 76
nuclear@2 77 main->cur_iMCU_row = 0; /* initialize counters */
nuclear@2 78 main->rowgroup_ctr = 0;
nuclear@2 79 main->suspended = FALSE;
nuclear@2 80 main->pass_mode = pass_mode; /* save mode for use by process_data */
nuclear@2 81
nuclear@2 82 switch (pass_mode) {
nuclear@2 83 case JBUF_PASS_THRU:
nuclear@2 84 #ifdef FULL_MAIN_BUFFER_SUPPORTED
nuclear@2 85 if (main->whole_image[0] != NULL)
nuclear@2 86 ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
nuclear@2 87 #endif
nuclear@2 88 main->pub.process_data = process_data_simple_main;
nuclear@2 89 break;
nuclear@2 90 #ifdef FULL_MAIN_BUFFER_SUPPORTED
nuclear@2 91 case JBUF_SAVE_SOURCE:
nuclear@2 92 case JBUF_CRANK_DEST:
nuclear@2 93 case JBUF_SAVE_AND_PASS:
nuclear@2 94 if (main->whole_image[0] == NULL)
nuclear@2 95 ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
nuclear@2 96 main->pub.process_data = process_data_buffer_main;
nuclear@2 97 break;
nuclear@2 98 #endif
nuclear@2 99 default:
nuclear@2 100 ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
nuclear@2 101 break;
nuclear@2 102 }
nuclear@2 103 }
nuclear@2 104
nuclear@2 105
nuclear@2 106 /*
nuclear@2 107 * Process some data.
nuclear@2 108 * This routine handles the simple pass-through mode,
nuclear@2 109 * where we have only a strip buffer.
nuclear@2 110 */
nuclear@2 111
nuclear@2 112 METHODDEF(void)
nuclear@2 113 process_data_simple_main (j_compress_ptr cinfo,
nuclear@2 114 JSAMPARRAY input_buf, JDIMENSION *in_row_ctr,
nuclear@2 115 JDIMENSION in_rows_avail)
nuclear@2 116 {
nuclear@2 117 my_main_ptr main = (my_main_ptr) cinfo->main;
nuclear@2 118
nuclear@2 119 while (main->cur_iMCU_row < cinfo->total_iMCU_rows) {
nuclear@2 120 /* Read input data if we haven't filled the main buffer yet */
nuclear@2 121 if (main->rowgroup_ctr < DCTSIZE)
nuclear@2 122 (*cinfo->prep->pre_process_data) (cinfo,
nuclear@2 123 input_buf, in_row_ctr, in_rows_avail,
nuclear@2 124 main->buffer, &main->rowgroup_ctr,
nuclear@2 125 (JDIMENSION) DCTSIZE);
nuclear@2 126
nuclear@2 127 /* If we don't have a full iMCU row buffered, return to application for
nuclear@2 128 * more data. Note that preprocessor will always pad to fill the iMCU row
nuclear@2 129 * at the bottom of the image.
nuclear@2 130 */
nuclear@2 131 if (main->rowgroup_ctr != DCTSIZE)
nuclear@2 132 return;
nuclear@2 133
nuclear@2 134 /* Send the completed row to the compressor */
nuclear@2 135 if (! (*cinfo->coef->compress_data) (cinfo, main->buffer)) {
nuclear@2 136 /* If compressor did not consume the whole row, then we must need to
nuclear@2 137 * suspend processing and return to the application. In this situation
nuclear@2 138 * we pretend we didn't yet consume the last input row; otherwise, if
nuclear@2 139 * it happened to be the last row of the image, the application would
nuclear@2 140 * think we were done.
nuclear@2 141 */
nuclear@2 142 if (! main->suspended) {
nuclear@2 143 (*in_row_ctr)--;
nuclear@2 144 main->suspended = TRUE;
nuclear@2 145 }
nuclear@2 146 return;
nuclear@2 147 }
nuclear@2 148 /* We did finish the row. Undo our little suspension hack if a previous
nuclear@2 149 * call suspended; then mark the main buffer empty.
nuclear@2 150 */
nuclear@2 151 if (main->suspended) {
nuclear@2 152 (*in_row_ctr)++;
nuclear@2 153 main->suspended = FALSE;
nuclear@2 154 }
nuclear@2 155 main->rowgroup_ctr = 0;
nuclear@2 156 main->cur_iMCU_row++;
nuclear@2 157 }
nuclear@2 158 }
nuclear@2 159
nuclear@2 160
nuclear@2 161 #ifdef FULL_MAIN_BUFFER_SUPPORTED
nuclear@2 162
nuclear@2 163 /*
nuclear@2 164 * Process some data.
nuclear@2 165 * This routine handles all of the modes that use a full-size buffer.
nuclear@2 166 */
nuclear@2 167
nuclear@2 168 METHODDEF(void)
nuclear@2 169 process_data_buffer_main (j_compress_ptr cinfo,
nuclear@2 170 JSAMPARRAY input_buf, JDIMENSION *in_row_ctr,
nuclear@2 171 JDIMENSION in_rows_avail)
nuclear@2 172 {
nuclear@2 173 my_main_ptr main = (my_main_ptr) cinfo->main;
nuclear@2 174 int ci;
nuclear@2 175 jpeg_component_info *compptr;
nuclear@2 176 boolean writing = (main->pass_mode != JBUF_CRANK_DEST);
nuclear@2 177
nuclear@2 178 while (main->cur_iMCU_row < cinfo->total_iMCU_rows) {
nuclear@2 179 /* Realign the virtual buffers if at the start of an iMCU row. */
nuclear@2 180 if (main->rowgroup_ctr == 0) {
nuclear@2 181 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
nuclear@2 182 ci++, compptr++) {
nuclear@2 183 main->buffer[ci] = (*cinfo->mem->access_virt_sarray)
nuclear@2 184 ((j_common_ptr) cinfo, main->whole_image[ci],
nuclear@2 185 main->cur_iMCU_row * (compptr->v_samp_factor * DCTSIZE),
nuclear@2 186 (JDIMENSION) (compptr->v_samp_factor * DCTSIZE), writing);
nuclear@2 187 }
nuclear@2 188 /* In a read pass, pretend we just read some source data. */
nuclear@2 189 if (! writing) {
nuclear@2 190 *in_row_ctr += cinfo->max_v_samp_factor * DCTSIZE;
nuclear@2 191 main->rowgroup_ctr = DCTSIZE;
nuclear@2 192 }
nuclear@2 193 }
nuclear@2 194
nuclear@2 195 /* If a write pass, read input data until the current iMCU row is full. */
nuclear@2 196 /* Note: preprocessor will pad if necessary to fill the last iMCU row. */
nuclear@2 197 if (writing) {
nuclear@2 198 (*cinfo->prep->pre_process_data) (cinfo,
nuclear@2 199 input_buf, in_row_ctr, in_rows_avail,
nuclear@2 200 main->buffer, &main->rowgroup_ctr,
nuclear@2 201 (JDIMENSION) DCTSIZE);
nuclear@2 202 /* Return to application if we need more data to fill the iMCU row. */
nuclear@2 203 if (main->rowgroup_ctr < DCTSIZE)
nuclear@2 204 return;
nuclear@2 205 }
nuclear@2 206
nuclear@2 207 /* Emit data, unless this is a sink-only pass. */
nuclear@2 208 if (main->pass_mode != JBUF_SAVE_SOURCE) {
nuclear@2 209 if (! (*cinfo->coef->compress_data) (cinfo, main->buffer)) {
nuclear@2 210 /* If compressor did not consume the whole row, then we must need to
nuclear@2 211 * suspend processing and return to the application. In this situation
nuclear@2 212 * we pretend we didn't yet consume the last input row; otherwise, if
nuclear@2 213 * it happened to be the last row of the image, the application would
nuclear@2 214 * think we were done.
nuclear@2 215 */
nuclear@2 216 if (! main->suspended) {
nuclear@2 217 (*in_row_ctr)--;
nuclear@2 218 main->suspended = TRUE;
nuclear@2 219 }
nuclear@2 220 return;
nuclear@2 221 }
nuclear@2 222 /* We did finish the row. Undo our little suspension hack if a previous
nuclear@2 223 * call suspended; then mark the main buffer empty.
nuclear@2 224 */
nuclear@2 225 if (main->suspended) {
nuclear@2 226 (*in_row_ctr)++;
nuclear@2 227 main->suspended = FALSE;
nuclear@2 228 }
nuclear@2 229 }
nuclear@2 230
nuclear@2 231 /* If get here, we are done with this iMCU row. Mark buffer empty. */
nuclear@2 232 main->rowgroup_ctr = 0;
nuclear@2 233 main->cur_iMCU_row++;
nuclear@2 234 }
nuclear@2 235 }
nuclear@2 236
nuclear@2 237 #endif /* FULL_MAIN_BUFFER_SUPPORTED */
nuclear@2 238
nuclear@2 239
nuclear@2 240 /*
nuclear@2 241 * Initialize main buffer controller.
nuclear@2 242 */
nuclear@2 243
nuclear@2 244 GLOBAL(void)
nuclear@2 245 jinit_c_main_controller (j_compress_ptr cinfo, boolean need_full_buffer)
nuclear@2 246 {
nuclear@2 247 my_main_ptr main;
nuclear@2 248 int ci;
nuclear@2 249 jpeg_component_info *compptr;
nuclear@2 250
nuclear@2 251 main = (my_main_ptr)
nuclear@2 252 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
nuclear@2 253 SIZEOF(my_main_controller));
nuclear@2 254 cinfo->main = (struct jpeg_c_main_controller *) main;
nuclear@2 255 main->pub.start_pass = start_pass_main;
nuclear@2 256
nuclear@2 257 /* We don't need to create a buffer in raw-data mode. */
nuclear@2 258 if (cinfo->raw_data_in)
nuclear@2 259 return;
nuclear@2 260
nuclear@2 261 /* Create the buffer. It holds downsampled data, so each component
nuclear@2 262 * may be of a different size.
nuclear@2 263 */
nuclear@2 264 if (need_full_buffer) {
nuclear@2 265 #ifdef FULL_MAIN_BUFFER_SUPPORTED
nuclear@2 266 /* Allocate a full-image virtual array for each component */
nuclear@2 267 /* Note we pad the bottom to a multiple of the iMCU height */
nuclear@2 268 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
nuclear@2 269 ci++, compptr++) {
nuclear@2 270 main->whole_image[ci] = (*cinfo->mem->request_virt_sarray)
nuclear@2 271 ((j_common_ptr) cinfo, JPOOL_IMAGE, FALSE,
nuclear@2 272 compptr->width_in_blocks * DCTSIZE,
nuclear@2 273 (JDIMENSION) jround_up((long) compptr->height_in_blocks,
nuclear@2 274 (long) compptr->v_samp_factor) * DCTSIZE,
nuclear@2 275 (JDIMENSION) (compptr->v_samp_factor * DCTSIZE));
nuclear@2 276 }
nuclear@2 277 #else
nuclear@2 278 ERREXIT(cinfo, JERR_BAD_BUFFER_MODE);
nuclear@2 279 #endif
nuclear@2 280 } else {
nuclear@2 281 #ifdef FULL_MAIN_BUFFER_SUPPORTED
nuclear@2 282 main->whole_image[0] = NULL; /* flag for no virtual arrays */
nuclear@2 283 #endif
nuclear@2 284 /* Allocate a strip buffer for each component */
nuclear@2 285 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
nuclear@2 286 ci++, compptr++) {
nuclear@2 287 main->buffer[ci] = (*cinfo->mem->alloc_sarray)
nuclear@2 288 ((j_common_ptr) cinfo, JPOOL_IMAGE,
nuclear@2 289 compptr->width_in_blocks * DCTSIZE,
nuclear@2 290 (JDIMENSION) (compptr->v_samp_factor * DCTSIZE));
nuclear@2 291 }
nuclear@2 292 }
nuclear@2 293 }