Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 1 | /* |
| 2 | * jdapistd.c |
| 3 | * |
DRC | a73e870 | 2012-12-31 02:52:30 +0000 | [diff] [blame] | 4 | * This file was part of the Independent JPEG Group's software: |
Thomas G. Lane | 489583f | 1996-02-07 00:00:00 +0000 | [diff] [blame] | 5 | * Copyright (C) 1994-1996, Thomas G. Lane. |
DRC | a6ef282 | 2013-09-28 03:23:49 +0000 | [diff] [blame] | 6 | * libjpeg-turbo Modifications: |
DRC | ce0dd94 | 2016-02-06 12:18:44 -0600 | [diff] [blame] | 7 | * Copyright (C) 2010, 2015-2016, D. R. Commander. |
DRC | eb32cc1 | 2015-06-25 03:44:36 +0000 | [diff] [blame] | 8 | * Copyright (C) 2015, Google, Inc. |
DRC | 7e3acc0 | 2015-10-10 10:25:46 -0500 | [diff] [blame] | 9 | * For conditions of distribution and use, see the accompanying README.ijg |
| 10 | * file. |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 11 | * |
| 12 | * This file contains application interface code for the decompression half |
| 13 | * of the JPEG library. These are the "standard" API routines that are |
| 14 | * used in the normal full-decompression case. They are not used by a |
| 15 | * transcoding-only application. Note that if an application links in |
| 16 | * jpeg_start_decompress, it will end up linking in the entire decompressor. |
| 17 | * We thus must separate this file from jdapimin.c to avoid linking the |
| 18 | * whole decompression library into a transcoder. |
| 19 | */ |
| 20 | |
DRC | ce0dd94 | 2016-02-06 12:18:44 -0600 | [diff] [blame] | 21 | #include "jinclude.h" |
DRC | eb32cc1 | 2015-06-25 03:44:36 +0000 | [diff] [blame] | 22 | #include "jdmainct.h" |
| 23 | #include "jdcoefct.h" |
| 24 | #include "jdsample.h" |
| 25 | #include "jmemsys.h" |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 26 | |
| 27 | /* Forward declarations */ |
DRC | bc56b75 | 2014-05-16 10:43:44 +0000 | [diff] [blame] | 28 | LOCAL(boolean) output_pass_setup (j_decompress_ptr cinfo); |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 29 | |
| 30 | |
| 31 | /* |
| 32 | * Decompression initialization. |
| 33 | * jpeg_read_header must be completed before calling this. |
| 34 | * |
| 35 | * If a multipass operating mode was selected, this will do all but the |
| 36 | * last pass, and thus may take a great deal of time. |
| 37 | * |
| 38 | * Returns FALSE if suspended. The return value need be inspected only if |
| 39 | * a suspending data source is used. |
| 40 | */ |
| 41 | |
Thomas G. Lane | 489583f | 1996-02-07 00:00:00 +0000 | [diff] [blame] | 42 | GLOBAL(boolean) |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 43 | jpeg_start_decompress (j_decompress_ptr cinfo) |
| 44 | { |
| 45 | if (cinfo->global_state == DSTATE_READY) { |
| 46 | /* First call: initialize master control, select active modules */ |
| 47 | jinit_master_decompress(cinfo); |
| 48 | if (cinfo->buffered_image) { |
| 49 | /* No more work here; expecting jpeg_start_output next */ |
| 50 | cinfo->global_state = DSTATE_BUFIMAGE; |
| 51 | return TRUE; |
| 52 | } |
| 53 | cinfo->global_state = DSTATE_PRELOAD; |
| 54 | } |
| 55 | if (cinfo->global_state == DSTATE_PRELOAD) { |
| 56 | /* If file has multiple scans, absorb them all into the coef buffer */ |
| 57 | if (cinfo->inputctl->has_multiple_scans) { |
| 58 | #ifdef D_MULTISCAN_FILES_SUPPORTED |
| 59 | for (;;) { |
DRC | e5eaf37 | 2014-05-09 18:00:32 +0000 | [diff] [blame] | 60 | int retcode; |
| 61 | /* Call progress monitor hook if present */ |
| 62 | if (cinfo->progress != NULL) |
| 63 | (*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo); |
| 64 | /* Absorb some more input */ |
| 65 | retcode = (*cinfo->inputctl->consume_input) (cinfo); |
| 66 | if (retcode == JPEG_SUSPENDED) |
| 67 | return FALSE; |
| 68 | if (retcode == JPEG_REACHED_EOI) |
| 69 | break; |
| 70 | /* Advance progress counter if appropriate */ |
| 71 | if (cinfo->progress != NULL && |
| 72 | (retcode == JPEG_ROW_COMPLETED || retcode == JPEG_REACHED_SOS)) { |
| 73 | if (++cinfo->progress->pass_counter >= cinfo->progress->pass_limit) { |
| 74 | /* jdmaster underestimated number of scans; ratchet up one scan */ |
| 75 | cinfo->progress->pass_limit += (long) cinfo->total_iMCU_rows; |
| 76 | } |
| 77 | } |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 78 | } |
| 79 | #else |
| 80 | ERREXIT(cinfo, JERR_NOT_COMPILED); |
| 81 | #endif /* D_MULTISCAN_FILES_SUPPORTED */ |
| 82 | } |
| 83 | cinfo->output_scan_number = cinfo->input_scan_number; |
| 84 | } else if (cinfo->global_state != DSTATE_PRESCAN) |
| 85 | ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); |
| 86 | /* Perform any dummy output passes, and set up for the final pass */ |
| 87 | return output_pass_setup(cinfo); |
| 88 | } |
| 89 | |
| 90 | |
| 91 | /* |
| 92 | * Set up for an output pass, and perform any dummy pass(es) needed. |
| 93 | * Common subroutine for jpeg_start_decompress and jpeg_start_output. |
| 94 | * Entry: global_state = DSTATE_PRESCAN only if previously suspended. |
| 95 | * Exit: If done, returns TRUE and sets global_state for proper output mode. |
| 96 | * If suspended, returns FALSE and sets global_state = DSTATE_PRESCAN. |
| 97 | */ |
| 98 | |
Thomas G. Lane | 489583f | 1996-02-07 00:00:00 +0000 | [diff] [blame] | 99 | LOCAL(boolean) |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 100 | output_pass_setup (j_decompress_ptr cinfo) |
| 101 | { |
| 102 | if (cinfo->global_state != DSTATE_PRESCAN) { |
| 103 | /* First call: do pass setup */ |
| 104 | (*cinfo->master->prepare_for_output_pass) (cinfo); |
| 105 | cinfo->output_scanline = 0; |
| 106 | cinfo->global_state = DSTATE_PRESCAN; |
| 107 | } |
| 108 | /* Loop over any required dummy passes */ |
| 109 | while (cinfo->master->is_dummy_pass) { |
| 110 | #ifdef QUANT_2PASS_SUPPORTED |
| 111 | /* Crank through the dummy pass */ |
| 112 | while (cinfo->output_scanline < cinfo->output_height) { |
| 113 | JDIMENSION last_scanline; |
| 114 | /* Call progress monitor hook if present */ |
| 115 | if (cinfo->progress != NULL) { |
DRC | e5eaf37 | 2014-05-09 18:00:32 +0000 | [diff] [blame] | 116 | cinfo->progress->pass_counter = (long) cinfo->output_scanline; |
| 117 | cinfo->progress->pass_limit = (long) cinfo->output_height; |
| 118 | (*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo); |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 119 | } |
| 120 | /* Process some data */ |
| 121 | last_scanline = cinfo->output_scanline; |
| 122 | (*cinfo->main->process_data) (cinfo, (JSAMPARRAY) NULL, |
DRC | e5eaf37 | 2014-05-09 18:00:32 +0000 | [diff] [blame] | 123 | &cinfo->output_scanline, (JDIMENSION) 0); |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 124 | if (cinfo->output_scanline == last_scanline) |
DRC | e5eaf37 | 2014-05-09 18:00:32 +0000 | [diff] [blame] | 125 | return FALSE; /* No progress made, must suspend */ |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 126 | } |
| 127 | /* Finish up dummy pass, and set up for another one */ |
| 128 | (*cinfo->master->finish_output_pass) (cinfo); |
| 129 | (*cinfo->master->prepare_for_output_pass) (cinfo); |
| 130 | cinfo->output_scanline = 0; |
| 131 | #else |
| 132 | ERREXIT(cinfo, JERR_NOT_COMPILED); |
| 133 | #endif /* QUANT_2PASS_SUPPORTED */ |
| 134 | } |
| 135 | /* Ready for application to drive output pass through |
| 136 | * jpeg_read_scanlines or jpeg_read_raw_data. |
| 137 | */ |
| 138 | cinfo->global_state = cinfo->raw_data_out ? DSTATE_RAW_OK : DSTATE_SCANNING; |
| 139 | return TRUE; |
| 140 | } |
| 141 | |
| 142 | |
| 143 | /* |
DRC | 3ab68cf | 2016-02-19 18:32:10 -0600 | [diff] [blame] | 144 | * Enable partial scanline decompression |
| 145 | * |
| 146 | * Must be called after jpeg_start_decompress() and before any calls to |
| 147 | * jpeg_read_scanlines() or jpeg_skip_scanlines(). |
| 148 | * |
| 149 | * Refer to libjpeg.txt for more information. |
| 150 | */ |
| 151 | |
| 152 | GLOBAL(void) |
| 153 | jpeg_crop_scanline (j_decompress_ptr cinfo, JDIMENSION *xoffset, |
| 154 | JDIMENSION *width) |
| 155 | { |
| 156 | int ci, align, orig_downsampled_width; |
| 157 | JDIMENSION input_xoffset; |
| 158 | boolean reinit_upsampler = FALSE; |
| 159 | jpeg_component_info *compptr; |
| 160 | |
| 161 | if (cinfo->global_state != DSTATE_SCANNING || cinfo->output_scanline != 0) |
| 162 | ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); |
| 163 | |
| 164 | if (!xoffset || !width) |
| 165 | ERREXIT(cinfo, JERR_BAD_CROP_SPEC); |
| 166 | |
| 167 | /* xoffset and width must fall within the output image dimensions. */ |
| 168 | if (*width == 0 || *xoffset + *width > cinfo->output_width) |
| 169 | ERREXIT(cinfo, JERR_WIDTH_OVERFLOW); |
| 170 | |
| 171 | /* No need to do anything if the caller wants the entire width. */ |
| 172 | if (*width == cinfo->output_width) |
| 173 | return; |
| 174 | |
| 175 | /* Ensuring the proper alignment of xoffset is tricky. At minimum, it |
| 176 | * must align with an MCU boundary, because: |
| 177 | * |
| 178 | * (1) The IDCT is performed in blocks, and it is not feasible to modify |
| 179 | * the algorithm so that it can transform partial blocks. |
| 180 | * (2) Because of the SIMD extensions, any input buffer passed to the |
| 181 | * upsampling and color conversion routines must be aligned to the |
| 182 | * SIMD word size (for instance, 128-bit in the case of SSE2.) The |
| 183 | * easiest way to accomplish this without copying data is to ensure |
| 184 | * that upsampling and color conversion begin at the start of the |
| 185 | * first MCU column that will be inverse transformed. |
| 186 | * |
| 187 | * In practice, we actually impose a stricter alignment requirement. We |
| 188 | * require that xoffset be a multiple of the maximum MCU column width of all |
| 189 | * of the components (the "iMCU column width.") This is to simplify the |
| 190 | * single-pass decompression case, allowing us to use the same MCU column |
| 191 | * width for all of the components. |
| 192 | */ |
DRC | 025c1f6 | 2016-02-22 10:00:19 -0600 | [diff] [blame] | 193 | align = cinfo->_min_DCT_scaled_size * cinfo->max_h_samp_factor; |
DRC | 3ab68cf | 2016-02-19 18:32:10 -0600 | [diff] [blame] | 194 | |
| 195 | /* Adjust xoffset to the nearest iMCU boundary <= the requested value */ |
| 196 | input_xoffset = *xoffset; |
| 197 | *xoffset = (input_xoffset / align) * align; |
| 198 | |
| 199 | /* Adjust the width so that the right edge of the output image is as |
| 200 | * requested (only the left edge is altered.) It is important that calling |
| 201 | * programs check this value after this function returns, so that they can |
| 202 | * allocate an output buffer with the appropriate size. |
| 203 | */ |
| 204 | *width = *width + input_xoffset - *xoffset; |
| 205 | cinfo->output_width = *width; |
| 206 | |
| 207 | /* Set the first and last iMCU columns that we must decompress. These values |
| 208 | * will be used in single-scan decompressions. |
| 209 | */ |
| 210 | cinfo->master->first_iMCU_col = |
| 211 | (JDIMENSION) (long) (*xoffset) / (long) align; |
| 212 | cinfo->master->last_iMCU_col = |
| 213 | (JDIMENSION) jdiv_round_up((long) (*xoffset + cinfo->output_width), |
| 214 | (long) align) - 1; |
| 215 | |
| 216 | for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; |
| 217 | ci++, compptr++) { |
| 218 | /* Set downsampled_width to the new output width. */ |
| 219 | orig_downsampled_width = compptr->downsampled_width; |
| 220 | compptr->downsampled_width = |
| 221 | (JDIMENSION) jdiv_round_up((long) (cinfo->output_width * |
| 222 | compptr->h_samp_factor), |
| 223 | (long) cinfo->max_h_samp_factor); |
| 224 | if (compptr->downsampled_width < 2 && orig_downsampled_width >= 2) |
| 225 | reinit_upsampler = TRUE; |
| 226 | |
| 227 | /* Set the first and last iMCU columns that we must decompress. These |
| 228 | * values will be used in multi-scan decompressions. |
| 229 | */ |
| 230 | cinfo->master->first_MCU_col[ci] = |
| 231 | (JDIMENSION) (long) (*xoffset * compptr->h_samp_factor) / |
| 232 | (long) align; |
| 233 | cinfo->master->last_MCU_col[ci] = |
| 234 | (JDIMENSION) jdiv_round_up((long) ((*xoffset + cinfo->output_width) * |
| 235 | compptr->h_samp_factor), |
| 236 | (long) align) - 1; |
| 237 | } |
| 238 | |
| 239 | if (reinit_upsampler) { |
| 240 | cinfo->master->jinit_upsampler_no_alloc = TRUE; |
| 241 | jinit_upsampler(cinfo); |
| 242 | cinfo->master->jinit_upsampler_no_alloc = FALSE; |
| 243 | } |
| 244 | } |
| 245 | |
| 246 | |
| 247 | /* |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 248 | * Read some scanlines of data from the JPEG decompressor. |
| 249 | * |
| 250 | * The return value will be the number of lines actually read. |
| 251 | * This may be less than the number requested in several cases, |
| 252 | * including bottom of image, data source suspension, and operating |
| 253 | * modes that emit multiple scanlines at a time. |
| 254 | * |
| 255 | * Note: we warn about excess calls to jpeg_read_scanlines() since |
| 256 | * this likely signals an application programmer error. However, |
| 257 | * an oversize buffer (max_lines > scanlines remaining) is not an error. |
| 258 | */ |
| 259 | |
Thomas G. Lane | 489583f | 1996-02-07 00:00:00 +0000 | [diff] [blame] | 260 | GLOBAL(JDIMENSION) |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 261 | jpeg_read_scanlines (j_decompress_ptr cinfo, JSAMPARRAY scanlines, |
DRC | e5eaf37 | 2014-05-09 18:00:32 +0000 | [diff] [blame] | 262 | JDIMENSION max_lines) |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 263 | { |
| 264 | JDIMENSION row_ctr; |
| 265 | |
| 266 | if (cinfo->global_state != DSTATE_SCANNING) |
| 267 | ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); |
| 268 | if (cinfo->output_scanline >= cinfo->output_height) { |
| 269 | WARNMS(cinfo, JWRN_TOO_MUCH_DATA); |
| 270 | return 0; |
| 271 | } |
| 272 | |
| 273 | /* Call progress monitor hook if present */ |
| 274 | if (cinfo->progress != NULL) { |
| 275 | cinfo->progress->pass_counter = (long) cinfo->output_scanline; |
| 276 | cinfo->progress->pass_limit = (long) cinfo->output_height; |
| 277 | (*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo); |
| 278 | } |
| 279 | |
| 280 | /* Process some data */ |
| 281 | row_ctr = 0; |
| 282 | (*cinfo->main->process_data) (cinfo, scanlines, &row_ctr, max_lines); |
| 283 | cinfo->output_scanline += row_ctr; |
| 284 | return row_ctr; |
| 285 | } |
| 286 | |
| 287 | |
DRC | 03e755b | 2015-07-21 17:36:18 -0500 | [diff] [blame] | 288 | /* Dummy color convert function used by jpeg_skip_scanlines() */ |
| 289 | LOCAL(void) |
| 290 | noop_convert (j_decompress_ptr cinfo, JSAMPIMAGE input_buf, |
| 291 | JDIMENSION input_row, JSAMPARRAY output_buf, int num_rows) |
| 292 | { |
| 293 | } |
| 294 | |
| 295 | |
| 296 | /* |
| 297 | * In some cases, it is best to call jpeg_read_scanlines() and discard the |
| 298 | * output, rather than skipping the scanlines, because this allows us to |
| 299 | * maintain the internal state of the context-based upsampler. In these cases, |
| 300 | * we set up and tear down a dummy color converter in order to avoid valgrind |
| 301 | * errors and to achieve the best possible performance. |
| 302 | */ |
DRC | eb32cc1 | 2015-06-25 03:44:36 +0000 | [diff] [blame] | 303 | |
| 304 | LOCAL(void) |
DRC | 03e755b | 2015-07-21 17:36:18 -0500 | [diff] [blame] | 305 | read_and_discard_scanlines (j_decompress_ptr cinfo, JDIMENSION num_lines) |
DRC | eb32cc1 | 2015-06-25 03:44:36 +0000 | [diff] [blame] | 306 | { |
DRC | 03e755b | 2015-07-21 17:36:18 -0500 | [diff] [blame] | 307 | JDIMENSION n; |
| 308 | void (*color_convert) (j_decompress_ptr cinfo, JSAMPIMAGE input_buf, |
| 309 | JDIMENSION input_row, JSAMPARRAY output_buf, |
| 310 | int num_rows); |
DRC | eb32cc1 | 2015-06-25 03:44:36 +0000 | [diff] [blame] | 311 | |
DRC | 03e755b | 2015-07-21 17:36:18 -0500 | [diff] [blame] | 312 | color_convert = cinfo->cconvert->color_convert; |
| 313 | cinfo->cconvert->color_convert = noop_convert; |
DRC | eb32cc1 | 2015-06-25 03:44:36 +0000 | [diff] [blame] | 314 | |
DRC | 03e755b | 2015-07-21 17:36:18 -0500 | [diff] [blame] | 315 | for (n = 0; n < num_lines; n++) |
| 316 | jpeg_read_scanlines(cinfo, NULL, 1); |
| 317 | |
| 318 | cinfo->cconvert->color_convert = color_convert; |
DRC | eb32cc1 | 2015-06-25 03:44:36 +0000 | [diff] [blame] | 319 | } |
| 320 | |
| 321 | |
| 322 | /* |
| 323 | * Called by jpeg_skip_scanlines(). This partially skips a decompress block by |
| 324 | * incrementing the rowgroup counter. |
| 325 | */ |
| 326 | |
| 327 | LOCAL(void) |
| 328 | increment_simple_rowgroup_ctr (j_decompress_ptr cinfo, JDIMENSION rows) |
| 329 | { |
DRC | 03e755b | 2015-07-21 17:36:18 -0500 | [diff] [blame] | 330 | JDIMENSION rows_left; |
DRC | eb32cc1 | 2015-06-25 03:44:36 +0000 | [diff] [blame] | 331 | my_main_ptr main_ptr = (my_main_ptr) cinfo->main; |
| 332 | |
| 333 | /* Increment the counter to the next row group after the skipped rows. */ |
| 334 | main_ptr->rowgroup_ctr += rows / cinfo->max_v_samp_factor; |
| 335 | |
| 336 | /* Partially skipping a row group would involve modifying the internal state |
| 337 | * of the upsampler, so read the remaining rows into a dummy buffer instead. |
| 338 | */ |
| 339 | rows_left = rows % cinfo->max_v_samp_factor; |
| 340 | cinfo->output_scanline += rows - rows_left; |
| 341 | |
DRC | 03e755b | 2015-07-21 17:36:18 -0500 | [diff] [blame] | 342 | read_and_discard_scanlines(cinfo, rows_left); |
DRC | eb32cc1 | 2015-06-25 03:44:36 +0000 | [diff] [blame] | 343 | } |
| 344 | |
DRC | eb32cc1 | 2015-06-25 03:44:36 +0000 | [diff] [blame] | 345 | /* |
| 346 | * Skips some scanlines of data from the JPEG decompressor. |
| 347 | * |
| 348 | * The return value will be the number of lines actually skipped. If skipping |
| 349 | * num_lines would move beyond the end of the image, then the actual number of |
| 350 | * lines remaining in the image is returned. Otherwise, the return value will |
| 351 | * be equal to num_lines. |
| 352 | * |
| 353 | * Refer to libjpeg.txt for more information. |
| 354 | */ |
| 355 | |
| 356 | GLOBAL(JDIMENSION) |
| 357 | jpeg_skip_scanlines (j_decompress_ptr cinfo, JDIMENSION num_lines) |
| 358 | { |
| 359 | my_main_ptr main_ptr = (my_main_ptr) cinfo->main; |
| 360 | my_coef_ptr coef = (my_coef_ptr) cinfo->coef; |
| 361 | my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample; |
DRC | 162c998 | 2015-06-27 08:10:32 +0000 | [diff] [blame] | 362 | JDIMENSION i, x; |
| 363 | int y; |
DRC | eb32cc1 | 2015-06-25 03:44:36 +0000 | [diff] [blame] | 364 | JDIMENSION lines_per_iMCU_row, lines_left_in_iMCU_row, lines_after_iMCU_row; |
| 365 | JDIMENSION lines_to_skip, lines_to_read; |
| 366 | |
| 367 | if (cinfo->global_state != DSTATE_SCANNING) |
| 368 | ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); |
| 369 | |
| 370 | /* Do not skip past the bottom of the image. */ |
| 371 | if (cinfo->output_scanline + num_lines >= cinfo->output_height) { |
| 372 | cinfo->output_scanline = cinfo->output_height; |
| 373 | return cinfo->output_height - cinfo->output_scanline; |
| 374 | } |
| 375 | |
| 376 | if (num_lines == 0) |
| 377 | return 0; |
| 378 | |
| 379 | lines_per_iMCU_row = cinfo->_min_DCT_scaled_size * cinfo->max_v_samp_factor; |
| 380 | lines_left_in_iMCU_row = |
| 381 | (lines_per_iMCU_row - (cinfo->output_scanline % lines_per_iMCU_row)) % |
| 382 | lines_per_iMCU_row; |
| 383 | lines_after_iMCU_row = num_lines - lines_left_in_iMCU_row; |
| 384 | |
| 385 | /* Skip the lines remaining in the current iMCU row. When upsampling |
| 386 | * requires context rows, we need the previous and next rows in order to read |
| 387 | * the current row. This adds some complexity. |
| 388 | */ |
| 389 | if (cinfo->upsample->need_context_rows) { |
| 390 | /* If the skipped lines would not move us past the current iMCU row, we |
| 391 | * read the lines and ignore them. There might be a faster way of doing |
| 392 | * this, but we are facing increasing complexity for diminishing returns. |
| 393 | * The increasing complexity would be a by-product of meddling with the |
| 394 | * state machine used to skip context rows. Near the end of an iMCU row, |
| 395 | * the next iMCU row may have already been entropy-decoded. In this unique |
| 396 | * case, we will read the next iMCU row if we cannot skip past it as well. |
| 397 | */ |
| 398 | if ((num_lines < lines_left_in_iMCU_row + 1) || |
| 399 | (lines_left_in_iMCU_row <= 1 && main_ptr->buffer_full && |
| 400 | lines_after_iMCU_row < lines_per_iMCU_row + 1)) { |
DRC | 03e755b | 2015-07-21 17:36:18 -0500 | [diff] [blame] | 401 | read_and_discard_scanlines(cinfo, num_lines); |
DRC | eb32cc1 | 2015-06-25 03:44:36 +0000 | [diff] [blame] | 402 | return num_lines; |
| 403 | } |
| 404 | |
| 405 | /* If the next iMCU row has already been entropy-decoded, make sure that |
| 406 | * we do not skip too far. |
| 407 | */ |
| 408 | if (lines_left_in_iMCU_row <= 1 && main_ptr->buffer_full) { |
| 409 | cinfo->output_scanline += lines_left_in_iMCU_row + lines_per_iMCU_row; |
| 410 | lines_after_iMCU_row -= lines_per_iMCU_row; |
| 411 | } else { |
| 412 | cinfo->output_scanline += lines_left_in_iMCU_row; |
| 413 | } |
DRC | ac09954 | 2015-06-27 08:10:30 +0000 | [diff] [blame] | 414 | |
| 415 | /* If we have just completed the first block, adjust the buffer pointers */ |
| 416 | if (main_ptr->iMCU_row_ctr == 0 || |
| 417 | (main_ptr->iMCU_row_ctr == 1 && lines_left_in_iMCU_row > 2)) |
| 418 | set_wraparound_pointers(cinfo); |
DRC | eb32cc1 | 2015-06-25 03:44:36 +0000 | [diff] [blame] | 419 | main_ptr->buffer_full = FALSE; |
| 420 | main_ptr->rowgroup_ctr = 0; |
| 421 | main_ptr->context_state = CTX_PREPARE_FOR_IMCU; |
| 422 | upsample->next_row_out = cinfo->max_v_samp_factor; |
| 423 | upsample->rows_to_go = cinfo->output_height - cinfo->output_scanline; |
| 424 | } |
| 425 | |
| 426 | /* Skipping is much simpler when context rows are not required. */ |
| 427 | else { |
| 428 | if (num_lines < lines_left_in_iMCU_row) { |
| 429 | increment_simple_rowgroup_ctr(cinfo, num_lines); |
| 430 | return num_lines; |
| 431 | } else { |
| 432 | cinfo->output_scanline += lines_left_in_iMCU_row; |
| 433 | main_ptr->buffer_full = FALSE; |
| 434 | main_ptr->rowgroup_ctr = 0; |
| 435 | upsample->next_row_out = cinfo->max_v_samp_factor; |
| 436 | upsample->rows_to_go = cinfo->output_height - cinfo->output_scanline; |
| 437 | } |
| 438 | } |
| 439 | |
| 440 | /* Calculate how many full iMCU rows we can skip. */ |
| 441 | if (cinfo->upsample->need_context_rows) |
| 442 | lines_to_skip = ((lines_after_iMCU_row - 1) / lines_per_iMCU_row) * |
| 443 | lines_per_iMCU_row; |
| 444 | else |
| 445 | lines_to_skip = (lines_after_iMCU_row / lines_per_iMCU_row) * |
| 446 | lines_per_iMCU_row; |
| 447 | /* Calculate the number of lines that remain to be skipped after skipping all |
| 448 | * of the full iMCU rows that we can. We will not read these lines unless we |
| 449 | * have to. |
| 450 | */ |
| 451 | lines_to_read = lines_after_iMCU_row - lines_to_skip; |
| 452 | |
| 453 | /* For images requiring multiple scans (progressive, non-interleaved, etc.), |
| 454 | * all of the entropy decoding occurs in jpeg_start_decompress(), assuming |
| 455 | * that the input data source is non-suspending. This makes skipping easy. |
| 456 | */ |
| 457 | if (cinfo->inputctl->has_multiple_scans) { |
| 458 | if (cinfo->upsample->need_context_rows) { |
| 459 | cinfo->output_scanline += lines_to_skip; |
| 460 | cinfo->output_iMCU_row += lines_to_skip / lines_per_iMCU_row; |
DRC | ac09954 | 2015-06-27 08:10:30 +0000 | [diff] [blame] | 461 | main_ptr->iMCU_row_ctr += lines_after_iMCU_row / lines_per_iMCU_row; |
DRC | eb32cc1 | 2015-06-25 03:44:36 +0000 | [diff] [blame] | 462 | /* It is complex to properly move to the middle of a context block, so |
| 463 | * read the remaining lines instead of skipping them. |
| 464 | */ |
DRC | 03e755b | 2015-07-21 17:36:18 -0500 | [diff] [blame] | 465 | read_and_discard_scanlines(cinfo, lines_to_read); |
DRC | eb32cc1 | 2015-06-25 03:44:36 +0000 | [diff] [blame] | 466 | } else { |
| 467 | cinfo->output_scanline += lines_to_skip; |
| 468 | cinfo->output_iMCU_row += lines_to_skip / lines_per_iMCU_row; |
| 469 | increment_simple_rowgroup_ctr(cinfo, lines_to_read); |
| 470 | } |
| 471 | upsample->rows_to_go = cinfo->output_height - cinfo->output_scanline; |
| 472 | return num_lines; |
| 473 | } |
| 474 | |
| 475 | /* Skip the iMCU rows that we can safely skip. */ |
| 476 | for (i = 0; i < lines_to_skip; i += lines_per_iMCU_row) { |
| 477 | for (y = 0; y < coef->MCU_rows_per_iMCU_row; y++) { |
| 478 | for (x = 0; x < cinfo->MCUs_per_row; x++) { |
| 479 | /* Calling decode_mcu() with a NULL pointer causes it to discard the |
| 480 | * decoded coefficients. This is ~5% faster for large subsets, but |
DRC | ac09954 | 2015-06-27 08:10:30 +0000 | [diff] [blame] | 481 | * it's tough to tell a difference for smaller images. |
DRC | eb32cc1 | 2015-06-25 03:44:36 +0000 | [diff] [blame] | 482 | */ |
| 483 | (*cinfo->entropy->decode_mcu) (cinfo, NULL); |
| 484 | } |
| 485 | } |
| 486 | cinfo->input_iMCU_row++; |
| 487 | cinfo->output_iMCU_row++; |
| 488 | if (cinfo->input_iMCU_row < cinfo->total_iMCU_rows) |
| 489 | start_iMCU_row(cinfo); |
| 490 | else |
| 491 | (*cinfo->inputctl->finish_input_pass) (cinfo); |
| 492 | } |
| 493 | cinfo->output_scanline += lines_to_skip; |
| 494 | |
| 495 | if (cinfo->upsample->need_context_rows) { |
| 496 | /* Context-based upsampling keeps track of iMCU rows. */ |
DRC | ac09954 | 2015-06-27 08:10:30 +0000 | [diff] [blame] | 497 | main_ptr->iMCU_row_ctr += lines_to_skip / lines_per_iMCU_row; |
DRC | eb32cc1 | 2015-06-25 03:44:36 +0000 | [diff] [blame] | 498 | |
| 499 | /* It is complex to properly move to the middle of a context block, so |
| 500 | * read the remaining lines instead of skipping them. |
| 501 | */ |
DRC | 03e755b | 2015-07-21 17:36:18 -0500 | [diff] [blame] | 502 | read_and_discard_scanlines(cinfo, lines_to_read); |
DRC | eb32cc1 | 2015-06-25 03:44:36 +0000 | [diff] [blame] | 503 | } else { |
| 504 | increment_simple_rowgroup_ctr(cinfo, lines_to_read); |
| 505 | } |
| 506 | |
| 507 | /* Since skipping lines involves skipping the upsampling step, the value of |
| 508 | * "rows_to_go" will become invalid unless we set it here. NOTE: This is a |
| 509 | * bit odd, since "rows_to_go" seems to be redundantly keeping track of |
| 510 | * output_scanline. |
| 511 | */ |
| 512 | upsample->rows_to_go = cinfo->output_height - cinfo->output_scanline; |
| 513 | |
| 514 | /* Always skip the requested number of lines. */ |
| 515 | return num_lines; |
| 516 | } |
| 517 | |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 518 | /* |
| 519 | * Alternate entry point to read raw data. |
| 520 | * Processes exactly one iMCU row per call, unless suspended. |
| 521 | */ |
| 522 | |
Thomas G. Lane | 489583f | 1996-02-07 00:00:00 +0000 | [diff] [blame] | 523 | GLOBAL(JDIMENSION) |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 524 | jpeg_read_raw_data (j_decompress_ptr cinfo, JSAMPIMAGE data, |
DRC | e5eaf37 | 2014-05-09 18:00:32 +0000 | [diff] [blame] | 525 | JDIMENSION max_lines) |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 526 | { |
| 527 | JDIMENSION lines_per_iMCU_row; |
| 528 | |
| 529 | if (cinfo->global_state != DSTATE_RAW_OK) |
| 530 | ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); |
| 531 | if (cinfo->output_scanline >= cinfo->output_height) { |
| 532 | WARNMS(cinfo, JWRN_TOO_MUCH_DATA); |
| 533 | return 0; |
| 534 | } |
| 535 | |
| 536 | /* Call progress monitor hook if present */ |
| 537 | if (cinfo->progress != NULL) { |
| 538 | cinfo->progress->pass_counter = (long) cinfo->output_scanline; |
| 539 | cinfo->progress->pass_limit = (long) cinfo->output_height; |
| 540 | (*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo); |
| 541 | } |
| 542 | |
| 543 | /* Verify that at least one iMCU row can be returned. */ |
DRC | 49967cd | 2010-10-09 19:57:51 +0000 | [diff] [blame] | 544 | lines_per_iMCU_row = cinfo->max_v_samp_factor * cinfo->_min_DCT_scaled_size; |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 545 | if (max_lines < lines_per_iMCU_row) |
| 546 | ERREXIT(cinfo, JERR_BUFFER_SIZE); |
| 547 | |
| 548 | /* Decompress directly into user's buffer. */ |
| 549 | if (! (*cinfo->coef->decompress_data) (cinfo, data)) |
DRC | e5eaf37 | 2014-05-09 18:00:32 +0000 | [diff] [blame] | 550 | return 0; /* suspension forced, can do nothing more */ |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 551 | |
| 552 | /* OK, we processed one iMCU row. */ |
| 553 | cinfo->output_scanline += lines_per_iMCU_row; |
| 554 | return lines_per_iMCU_row; |
| 555 | } |
| 556 | |
| 557 | |
| 558 | /* Additional entry points for buffered-image mode. */ |
| 559 | |
| 560 | #ifdef D_MULTISCAN_FILES_SUPPORTED |
| 561 | |
| 562 | /* |
| 563 | * Initialize for an output pass in buffered-image mode. |
| 564 | */ |
| 565 | |
Thomas G. Lane | 489583f | 1996-02-07 00:00:00 +0000 | [diff] [blame] | 566 | GLOBAL(boolean) |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 567 | jpeg_start_output (j_decompress_ptr cinfo, int scan_number) |
| 568 | { |
| 569 | if (cinfo->global_state != DSTATE_BUFIMAGE && |
| 570 | cinfo->global_state != DSTATE_PRESCAN) |
| 571 | ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); |
| 572 | /* Limit scan number to valid range */ |
| 573 | if (scan_number <= 0) |
| 574 | scan_number = 1; |
| 575 | if (cinfo->inputctl->eoi_reached && |
| 576 | scan_number > cinfo->input_scan_number) |
| 577 | scan_number = cinfo->input_scan_number; |
| 578 | cinfo->output_scan_number = scan_number; |
| 579 | /* Perform any dummy output passes, and set up for the real pass */ |
| 580 | return output_pass_setup(cinfo); |
| 581 | } |
| 582 | |
| 583 | |
| 584 | /* |
| 585 | * Finish up after an output pass in buffered-image mode. |
| 586 | * |
| 587 | * Returns FALSE if suspended. The return value need be inspected only if |
| 588 | * a suspending data source is used. |
| 589 | */ |
| 590 | |
Thomas G. Lane | 489583f | 1996-02-07 00:00:00 +0000 | [diff] [blame] | 591 | GLOBAL(boolean) |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 592 | jpeg_finish_output (j_decompress_ptr cinfo) |
| 593 | { |
| 594 | if ((cinfo->global_state == DSTATE_SCANNING || |
| 595 | cinfo->global_state == DSTATE_RAW_OK) && cinfo->buffered_image) { |
| 596 | /* Terminate this pass. */ |
| 597 | /* We do not require the whole pass to have been completed. */ |
| 598 | (*cinfo->master->finish_output_pass) (cinfo); |
| 599 | cinfo->global_state = DSTATE_BUFPOST; |
| 600 | } else if (cinfo->global_state != DSTATE_BUFPOST) { |
| 601 | /* BUFPOST = repeat call after a suspension, anything else is error */ |
| 602 | ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); |
| 603 | } |
| 604 | /* Read markers looking for SOS or EOI */ |
| 605 | while (cinfo->input_scan_number <= cinfo->output_scan_number && |
DRC | e5eaf37 | 2014-05-09 18:00:32 +0000 | [diff] [blame] | 606 | ! cinfo->inputctl->eoi_reached) { |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 607 | if ((*cinfo->inputctl->consume_input) (cinfo) == JPEG_SUSPENDED) |
DRC | e5eaf37 | 2014-05-09 18:00:32 +0000 | [diff] [blame] | 608 | return FALSE; /* Suspend, come back later */ |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 609 | } |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 610 | cinfo->global_state = DSTATE_BUFIMAGE; |
| 611 | return TRUE; |
| 612 | } |
| 613 | |
| 614 | #endif /* D_MULTISCAN_FILES_SUPPORTED */ |