jcapistd.c (6551B)
1 /* 2 * jcapistd.c 3 * 4 * This file was part of the Independent JPEG Group's software: 5 * Copyright (C) 1994-1996, Thomas G. Lane. 6 * libjpeg-turbo Modifications: 7 * Copyright (C) 2022, D. R. Commander. 8 * For conditions of distribution and use, see the accompanying README.ijg 9 * file. 10 * 11 * This file contains application interface code for the compression half 12 * of the JPEG library. These are the "standard" API routines that are 13 * used in the normal full-compression case. They are not used by a 14 * transcoding-only application. Note that if an application links in 15 * jpeg_start_compress, it will end up linking in the entire compressor. 16 * We thus must separate this file from jcapimin.c to avoid linking the 17 * whole compression library into a transcoder. 18 */ 19 20 #define JPEG_INTERNALS 21 #include "jinclude.h" 22 #include "jpeglib.h" 23 #include "jsamplecomp.h" 24 25 26 #if BITS_IN_JSAMPLE == 8 27 28 /* 29 * Compression initialization. 30 * Before calling this, all parameters and a data destination must be set up. 31 * 32 * We require a write_all_tables parameter as a failsafe check when writing 33 * multiple datastreams from the same compression object. Since prior runs 34 * will have left all the tables marked sent_table=TRUE, a subsequent run 35 * would emit an abbreviated stream (no tables) by default. This may be what 36 * is wanted, but for safety's sake it should not be the default behavior: 37 * programmers should have to make a deliberate choice to emit abbreviated 38 * images. Therefore the documentation and examples should encourage people 39 * to pass write_all_tables=TRUE; then it will take active thought to do the 40 * wrong thing. 41 */ 42 43 GLOBAL(void) 44 jpeg_start_compress(j_compress_ptr cinfo, boolean write_all_tables) 45 { 46 if (cinfo->global_state != CSTATE_START) 47 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); 48 49 if (write_all_tables) 50 jpeg_suppress_tables(cinfo, FALSE); /* mark all tables to be written */ 51 52 /* (Re)initialize error mgr and destination modules */ 53 (*cinfo->err->reset_error_mgr) ((j_common_ptr)cinfo); 54 (*cinfo->dest->init_destination) (cinfo); 55 /* Perform master selection of active modules */ 56 jinit_compress_master(cinfo); 57 /* Set up for the first pass */ 58 (*cinfo->master->prepare_for_pass) (cinfo); 59 /* Ready for application to drive first pass through _jpeg_write_scanlines 60 * or _jpeg_write_raw_data. 61 */ 62 cinfo->next_scanline = 0; 63 cinfo->global_state = (cinfo->raw_data_in ? CSTATE_RAW_OK : CSTATE_SCANNING); 64 } 65 66 #endif 67 68 69 /* 70 * Write some scanlines of data to the JPEG compressor. 71 * 72 * The return value will be the number of lines actually written. 73 * This should be less than the supplied num_lines only in case that 74 * the data destination module has requested suspension of the compressor, 75 * or if more than image_height scanlines are passed in. 76 * 77 * Note: we warn about excess calls to _jpeg_write_scanlines() since 78 * this likely signals an application programmer error. However, 79 * excess scanlines passed in the last valid call are *silently* ignored, 80 * so that the application need not adjust num_lines for end-of-image 81 * when using a multiple-scanline buffer. 82 */ 83 84 GLOBAL(JDIMENSION) 85 _jpeg_write_scanlines(j_compress_ptr cinfo, _JSAMPARRAY scanlines, 86 JDIMENSION num_lines) 87 { 88 #if BITS_IN_JSAMPLE != 16 || defined(C_LOSSLESS_SUPPORTED) 89 JDIMENSION row_ctr, rows_left; 90 91 if (cinfo->data_precision != BITS_IN_JSAMPLE) 92 ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision); 93 94 if (cinfo->global_state != CSTATE_SCANNING) 95 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); 96 if (cinfo->next_scanline >= cinfo->image_height) 97 WARNMS(cinfo, JWRN_TOO_MUCH_DATA); 98 99 /* Call progress monitor hook if present */ 100 if (cinfo->progress != NULL) { 101 cinfo->progress->pass_counter = (long)cinfo->next_scanline; 102 cinfo->progress->pass_limit = (long)cinfo->image_height; 103 (*cinfo->progress->progress_monitor) ((j_common_ptr)cinfo); 104 } 105 106 /* Give master control module another chance if this is first call to 107 * _jpeg_write_scanlines. This lets output of the frame/scan headers be 108 * delayed so that application can write COM, etc, markers between 109 * jpeg_start_compress and _jpeg_write_scanlines. 110 */ 111 if (cinfo->master->call_pass_startup) 112 (*cinfo->master->pass_startup) (cinfo); 113 114 /* Ignore any extra scanlines at bottom of image. */ 115 rows_left = cinfo->image_height - cinfo->next_scanline; 116 if (num_lines > rows_left) 117 num_lines = rows_left; 118 119 row_ctr = 0; 120 (*cinfo->main->_process_data) (cinfo, scanlines, &row_ctr, num_lines); 121 cinfo->next_scanline += row_ctr; 122 return row_ctr; 123 #else 124 ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision); 125 return 0; 126 #endif 127 } 128 129 130 #if BITS_IN_JSAMPLE != 16 131 132 /* 133 * Alternate entry point to write raw data. 134 * Processes exactly one iMCU row per call, unless suspended. 135 */ 136 137 GLOBAL(JDIMENSION) 138 _jpeg_write_raw_data(j_compress_ptr cinfo, _JSAMPIMAGE data, 139 JDIMENSION num_lines) 140 { 141 JDIMENSION lines_per_iMCU_row; 142 143 if (cinfo->data_precision != BITS_IN_JSAMPLE) 144 ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision); 145 146 if (cinfo->master->lossless) 147 ERREXIT(cinfo, JERR_NOTIMPL); 148 149 if (cinfo->global_state != CSTATE_RAW_OK) 150 ERREXIT1(cinfo, JERR_BAD_STATE, cinfo->global_state); 151 if (cinfo->next_scanline >= cinfo->image_height) { 152 WARNMS(cinfo, JWRN_TOO_MUCH_DATA); 153 return 0; 154 } 155 156 /* Call progress monitor hook if present */ 157 if (cinfo->progress != NULL) { 158 cinfo->progress->pass_counter = (long)cinfo->next_scanline; 159 cinfo->progress->pass_limit = (long)cinfo->image_height; 160 (*cinfo->progress->progress_monitor) ((j_common_ptr)cinfo); 161 } 162 163 /* Give master control module another chance if this is first call to 164 * _jpeg_write_raw_data. This lets output of the frame/scan headers be 165 * delayed so that application can write COM, etc, markers between 166 * jpeg_start_compress and _jpeg_write_raw_data. 167 */ 168 if (cinfo->master->call_pass_startup) 169 (*cinfo->master->pass_startup) (cinfo); 170 171 /* Verify that at least one iMCU row has been passed. */ 172 lines_per_iMCU_row = cinfo->max_v_samp_factor * DCTSIZE; 173 if (num_lines < lines_per_iMCU_row) 174 ERREXIT(cinfo, JERR_BUFFER_SIZE); 175 176 /* Directly compress the row. */ 177 if (!(*cinfo->coef->_compress_data) (cinfo, data)) { 178 /* If compressor did not consume the whole row, suspend processing. */ 179 return 0; 180 } 181 182 /* OK, we processed one iMCU row. */ 183 cinfo->next_scanline += lines_per_iMCU_row; 184 return lines_per_iMCU_row; 185 } 186 187 #endif /* BITS_IN_JSAMPLE != 16 */