1 #if !defined(_FX_JPEG_TURBO_) 2 /* 3 * jdapistd.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 application interface code for the decompression half 10 * of the JPEG library. These are the "standard" API routines that are 11 * used in the normal full-decompression case. They are not used by a 12 * transcoding-only application. Note that if an application links in 13 * jpeg_start_decompress, it will end up linking in the entire decompressor. 14 * We thus must separate this file from jdapimin.c to avoid linking the 15 * whole decompression library into a transcoder. 16 */ 17 18 #define JPEG_INTERNALS 19 #include "jinclude.h" 20 #include "jpeglib.h" 21 22 23 /* Forward declarations */ 24 LOCAL(boolean) output_pass_setup JPP((j_decompress_ptr cinfo)); 25 26 27 /* 28 * Decompression initialization. 29 * jpeg_read_header must be completed before calling this. 30 * 31 * If a multipass operating mode was selected, this will do all but the 32 * last pass, and thus may take a great deal of time. 33 * 34 * Returns FALSE if suspended. The return value need be inspected only if 35 * a suspending data source is used. 36 */ 37 38 GLOBAL(boolean) 39 jpeg_start_decompress (j_decompress_ptr cinfo) 40 { 41 if (cinfo->global_state == DSTATE_READY) { 42 /* First call: initialize master control, select active modules */ 43 jinit_master_decompress(cinfo); 44 if (cinfo->buffered_image) { 45 /* No more work here; expecting jpeg_start_output next */ 46 cinfo->global_state = DSTATE_BUFIMAGE; 47 return TRUE; 48 } 49 cinfo->global_state = DSTATE_PRELOAD; 50 } 51 if (cinfo->global_state == DSTATE_PRELOAD) { 52 /* If file has multiple scans, absorb them all into the coef buffer */ 53 if (cinfo->inputctl->has_multiple_scans) { 54 #ifdef D_MULTISCAN_FILES_SUPPORTED 55 for (;;) { 56 int retcode; 57 /* Call progress monitor hook if present */ 58 if (cinfo->progress != NULL) 59 (*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo); 60 /* Absorb some more input */ 61 retcode = (*cinfo->inputctl->consume_input) (cinfo); 62 if (retcode == JPEG_SUSPENDED) 63 return FALSE; 64 if (retcode == JPEG_REACHED_EOI) 65 break; 66 /* Advance progress counter if appropriate */ 67 if (cinfo->progress != NULL && 68 (retcode == JPEG_ROW_COMPLETED || retcode == JPEG_REACHED_SOS)) { 69 if (++cinfo->progress->pass_counter >= cinfo->progress->pass_limit) { 70 /* jdmaster underestimated number of scans; ratchet up one scan */ 71 cinfo->progress->pass_limit += (long) cinfo->total_iMCU_rows; 72 } 73 } 74 } 75 #else 76 ERREXIT(cinfo, JERR_NOT_COMPILED); 77 #endif /* D_MULTISCAN_FILES_SUPPORTED */ 78 } 79 cinfo->output_scan_number = cinfo->input_scan_number; 80 } else if (cinfo->global_state != DSTATE_PRESCAN) 81 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); 82 /* Perform any dummy output passes, and set up for the final pass */ 83 return output_pass_setup(cinfo); 84 } 85 86 87 /* 88 * Set up for an output pass, and perform any dummy pass(es) needed. 89 * Common subroutine for jpeg_start_decompress and jpeg_start_output. 90 * Entry: global_state = DSTATE_PRESCAN only if previously suspended. 91 * Exit: If done, returns TRUE and sets global_state for proper output mode. 92 * If suspended, returns FALSE and sets global_state = DSTATE_PRESCAN. 93 */ 94 95 LOCAL(boolean) 96 output_pass_setup (j_decompress_ptr cinfo) 97 { 98 if (cinfo->global_state != DSTATE_PRESCAN) { 99 /* First call: do pass setup */ 100 (*cinfo->master->prepare_for_output_pass) (cinfo); 101 cinfo->output_scanline = 0; 102 cinfo->global_state = DSTATE_PRESCAN; 103 } 104 /* Loop over any required dummy passes */ 105 while (cinfo->master->is_dummy_pass) { 106 #ifdef QUANT_2PASS_SUPPORTED 107 /* Crank through the dummy pass */ 108 while (cinfo->output_scanline < cinfo->output_height) { 109 JDIMENSION last_scanline; 110 /* Call progress monitor hook if present */ 111 if (cinfo->progress != NULL) { 112 cinfo->progress->pass_counter = (long) cinfo->output_scanline; 113 cinfo->progress->pass_limit = (long) cinfo->output_height; 114 (*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo); 115 } 116 /* Process some data */ 117 last_scanline = cinfo->output_scanline; 118 (*cinfo->main->process_data) (cinfo, (JSAMPARRAY) NULL, 119 &cinfo->output_scanline, (JDIMENSION) 0); 120 if (cinfo->output_scanline == last_scanline) 121 return FALSE; /* No progress made, must suspend */ 122 } 123 /* Finish up dummy pass, and set up for another one */ 124 (*cinfo->master->finish_output_pass) (cinfo); 125 (*cinfo->master->prepare_for_output_pass) (cinfo); 126 cinfo->output_scanline = 0; 127 #else 128 ERREXIT(cinfo, JERR_NOT_COMPILED); 129 #endif /* QUANT_2PASS_SUPPORTED */ 130 } 131 /* Ready for application to drive output pass through 132 * jpeg_read_scanlines or jpeg_read_raw_data. 133 */ 134 cinfo->global_state = cinfo->raw_data_out ? DSTATE_RAW_OK : DSTATE_SCANNING; 135 return TRUE; 136 } 137 138 139 /* 140 * Read some scanlines of data from the JPEG decompressor. 141 * 142 * The return value will be the number of lines actually read. 143 * This may be less than the number requested in several cases, 144 * including bottom of image, data source suspension, and operating 145 * modes that emit multiple scanlines at a time. 146 * 147 * Note: we warn about excess calls to jpeg_read_scanlines() since 148 * this likely signals an application programmer error. However, 149 * an oversize buffer (max_lines > scanlines remaining) is not an error. 150 */ 151 152 GLOBAL(JDIMENSION) 153 jpeg_read_scanlines (j_decompress_ptr cinfo, JSAMPARRAY scanlines, 154 JDIMENSION max_lines) 155 { 156 JDIMENSION row_ctr; 157 158 if (cinfo->global_state != DSTATE_SCANNING) 159 return 0; /* XYQ 2010-6-27: don't throw exception here */ 160 /* ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); */ 161 if (cinfo->output_scanline >= cinfo->output_height) { 162 WARNMS(cinfo, JWRN_TOO_MUCH_DATA); 163 return 0; 164 } 165 166 /* Call progress monitor hook if present */ 167 if (cinfo->progress != NULL) { 168 cinfo->progress->pass_counter = (long) cinfo->output_scanline; 169 cinfo->progress->pass_limit = (long) cinfo->output_height; 170 (*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo); 171 } 172 173 /* Process some data */ 174 row_ctr = 0; 175 (*cinfo->main->process_data) (cinfo, scanlines, &row_ctr, max_lines); 176 cinfo->output_scanline += row_ctr; 177 return row_ctr; 178 } 179 180 181 /* 182 * Alternate entry point to read raw data. 183 * Processes exactly one iMCU row per call, unless suspended. 184 */ 185 186 GLOBAL(JDIMENSION) 187 jpeg_read_raw_data (j_decompress_ptr cinfo, JSAMPIMAGE data, 188 JDIMENSION max_lines) 189 { 190 JDIMENSION lines_per_iMCU_row; 191 192 if (cinfo->global_state != DSTATE_RAW_OK) 193 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); 194 if (cinfo->output_scanline >= cinfo->output_height) { 195 WARNMS(cinfo, JWRN_TOO_MUCH_DATA); 196 return 0; 197 } 198 199 /* Call progress monitor hook if present */ 200 if (cinfo->progress != NULL) { 201 cinfo->progress->pass_counter = (long) cinfo->output_scanline; 202 cinfo->progress->pass_limit = (long) cinfo->output_height; 203 (*cinfo->progress->progress_monitor) ((j_common_ptr) cinfo); 204 } 205 206 /* Verify that at least one iMCU row can be returned. */ 207 lines_per_iMCU_row = cinfo->max_v_samp_factor * cinfo->min_DCT_scaled_size; 208 if (max_lines < lines_per_iMCU_row) 209 ERREXIT(cinfo, JERR_BUFFER_SIZE); 210 211 /* Decompress directly into user's buffer. */ 212 if (! (*cinfo->coef->decompress_data) (cinfo, data)) 213 return 0; /* suspension forced, can do nothing more */ 214 215 /* OK, we processed one iMCU row. */ 216 cinfo->output_scanline += lines_per_iMCU_row; 217 return lines_per_iMCU_row; 218 } 219 220 221 /* Additional entry points for buffered-image mode. */ 222 223 #ifdef D_MULTISCAN_FILES_SUPPORTED 224 225 /* 226 * Initialize for an output pass in buffered-image mode. 227 */ 228 229 GLOBAL(boolean) 230 jpeg_start_output (j_decompress_ptr cinfo, int scan_number) 231 { 232 if (cinfo->global_state != DSTATE_BUFIMAGE && 233 cinfo->global_state != DSTATE_PRESCAN) 234 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); 235 /* Limit scan number to valid range */ 236 if (scan_number <= 0) 237 scan_number = 1; 238 if (cinfo->inputctl->eoi_reached && 239 scan_number > cinfo->input_scan_number) 240 scan_number = cinfo->input_scan_number; 241 cinfo->output_scan_number = scan_number; 242 /* Perform any dummy output passes, and set up for the real pass */ 243 return output_pass_setup(cinfo); 244 } 245 246 247 /* 248 * Finish up after an output pass in buffered-image mode. 249 * 250 * Returns FALSE if suspended. The return value need be inspected only if 251 * a suspending data source is used. 252 */ 253 254 GLOBAL(boolean) 255 jpeg_finish_output (j_decompress_ptr cinfo) 256 { 257 if ((cinfo->global_state == DSTATE_SCANNING || 258 cinfo->global_state == DSTATE_RAW_OK) && cinfo->buffered_image) { 259 /* Terminate this pass. */ 260 /* We do not require the whole pass to have been completed. */ 261 (*cinfo->master->finish_output_pass) (cinfo); 262 cinfo->global_state = DSTATE_BUFPOST; 263 } else if (cinfo->global_state != DSTATE_BUFPOST) { 264 /* BUFPOST = repeat call after a suspension, anything else is error */ 265 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); 266 } 267 /* Read markers looking for SOS or EOI */ 268 while (cinfo->input_scan_number <= cinfo->output_scan_number && 269 ! cinfo->inputctl->eoi_reached) { 270 if ((*cinfo->inputctl->consume_input) (cinfo) == JPEG_SUSPENDED) 271 return FALSE; /* Suspend, come back later */ 272 } 273 cinfo->global_state = DSTATE_BUFIMAGE; 274 return TRUE; 275 } 276 277 #endif /* D_MULTISCAN_FILES_SUPPORTED */ 278 279 #endif //_FX_JPEG_TURBO_ 280
