1 /* 2 * jcinit.c 3 * 4 * Copyright (C) 1991-1997, Thomas G. Lane. 5 * Modified 2003-2017 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 initialization logic for the JPEG compressor. 10 * This routine is in charge of selecting the modules to be executed and 11 * making an initialization call to each one. 12 * 13 * Logically, this code belongs in jcmaster.c. It's split out because 14 * linking this routine implies linking the entire compression library. 15 * For a transcoding-only application, we want to be able to use jcmaster.c 16 * without linking in the whole library. 17 */ 18 19 #define JPEG_INTERNALS 20 #include "jinclude.h" 21 #include "jpeglib.h" 22 23 24 /* 25 * Compute JPEG image dimensions and related values. 26 * NOTE: this is exported for possible use by application. 27 * Hence it mustn't do anything that can't be done twice. 28 */ 29 30 GLOBAL(void) 31 jpeg_calc_jpeg_dimensions (j_compress_ptr cinfo) 32 /* Do computations that are needed before master selection phase */ 33 { 34 /* Sanity check on input image dimensions to prevent overflow in 35 * following calculations. 36 * We do check jpeg_width and jpeg_height in initial_setup in jcmaster.c, 37 * but image_width and image_height can come from arbitrary data, 38 * and we need some space for multiplication by block_size. 39 */ 40 if (((long) cinfo->image_width >> 24) || ((long) cinfo->image_height >> 24)) 41 ERREXIT1(cinfo, JERR_IMAGE_TOO_BIG, (unsigned int) JPEG_MAX_DIMENSION); 42 43 #ifdef DCT_SCALING_SUPPORTED 44 45 /* Compute actual JPEG image dimensions and DCT scaling choices. */ 46 if (cinfo->scale_num >= cinfo->scale_denom * cinfo->block_size) { 47 /* Provide block_size/1 scaling */ 48 cinfo->jpeg_width = cinfo->image_width * cinfo->block_size; 49 cinfo->jpeg_height = cinfo->image_height * cinfo->block_size; 50 cinfo->min_DCT_h_scaled_size = 1; 51 cinfo->min_DCT_v_scaled_size = 1; 52 } else if (cinfo->scale_num * 2 >= cinfo->scale_denom * cinfo->block_size) { 53 /* Provide block_size/2 scaling */ 54 cinfo->jpeg_width = (JDIMENSION) 55 jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 2L); 56 cinfo->jpeg_height = (JDIMENSION) 57 jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 2L); 58 cinfo->min_DCT_h_scaled_size = 2; 59 cinfo->min_DCT_v_scaled_size = 2; 60 } else if (cinfo->scale_num * 3 >= cinfo->scale_denom * cinfo->block_size) { 61 /* Provide block_size/3 scaling */ 62 cinfo->jpeg_width = (JDIMENSION) 63 jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 3L); 64 cinfo->jpeg_height = (JDIMENSION) 65 jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 3L); 66 cinfo->min_DCT_h_scaled_size = 3; 67 cinfo->min_DCT_v_scaled_size = 3; 68 } else if (cinfo->scale_num * 4 >= cinfo->scale_denom * cinfo->block_size) { 69 /* Provide block_size/4 scaling */ 70 cinfo->jpeg_width = (JDIMENSION) 71 jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 4L); 72 cinfo->jpeg_height = (JDIMENSION) 73 jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 4L); 74 cinfo->min_DCT_h_scaled_size = 4; 75 cinfo->min_DCT_v_scaled_size = 4; 76 } else if (cinfo->scale_num * 5 >= cinfo->scale_denom * cinfo->block_size) { 77 /* Provide block_size/5 scaling */ 78 cinfo->jpeg_width = (JDIMENSION) 79 jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 5L); 80 cinfo->jpeg_height = (JDIMENSION) 81 jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 5L); 82 cinfo->min_DCT_h_scaled_size = 5; 83 cinfo->min_DCT_v_scaled_size = 5; 84 } else if (cinfo->scale_num * 6 >= cinfo->scale_denom * cinfo->block_size) { 85 /* Provide block_size/6 scaling */ 86 cinfo->jpeg_width = (JDIMENSION) 87 jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 6L); 88 cinfo->jpeg_height = (JDIMENSION) 89 jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 6L); 90 cinfo->min_DCT_h_scaled_size = 6; 91 cinfo->min_DCT_v_scaled_size = 6; 92 } else if (cinfo->scale_num * 7 >= cinfo->scale_denom * cinfo->block_size) { 93 /* Provide block_size/7 scaling */ 94 cinfo->jpeg_width = (JDIMENSION) 95 jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 7L); 96 cinfo->jpeg_height = (JDIMENSION) 97 jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 7L); 98 cinfo->min_DCT_h_scaled_size = 7; 99 cinfo->min_DCT_v_scaled_size = 7; 100 } else if (cinfo->scale_num * 8 >= cinfo->scale_denom * cinfo->block_size) { 101 /* Provide block_size/8 scaling */ 102 cinfo->jpeg_width = (JDIMENSION) 103 jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 8L); 104 cinfo->jpeg_height = (JDIMENSION) 105 jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 8L); 106 cinfo->min_DCT_h_scaled_size = 8; 107 cinfo->min_DCT_v_scaled_size = 8; 108 } else if (cinfo->scale_num * 9 >= cinfo->scale_denom * cinfo->block_size) { 109 /* Provide block_size/9 scaling */ 110 cinfo->jpeg_width = (JDIMENSION) 111 jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 9L); 112 cinfo->jpeg_height = (JDIMENSION) 113 jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 9L); 114 cinfo->min_DCT_h_scaled_size = 9; 115 cinfo->min_DCT_v_scaled_size = 9; 116 } else if (cinfo->scale_num * 10 >= cinfo->scale_denom * cinfo->block_size) { 117 /* Provide block_size/10 scaling */ 118 cinfo->jpeg_width = (JDIMENSION) 119 jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 10L); 120 cinfo->jpeg_height = (JDIMENSION) 121 jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 10L); 122 cinfo->min_DCT_h_scaled_size = 10; 123 cinfo->min_DCT_v_scaled_size = 10; 124 } else if (cinfo->scale_num * 11 >= cinfo->scale_denom * cinfo->block_size) { 125 /* Provide block_size/11 scaling */ 126 cinfo->jpeg_width = (JDIMENSION) 127 jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 11L); 128 cinfo->jpeg_height = (JDIMENSION) 129 jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 11L); 130 cinfo->min_DCT_h_scaled_size = 11; 131 cinfo->min_DCT_v_scaled_size = 11; 132 } else if (cinfo->scale_num * 12 >= cinfo->scale_denom * cinfo->block_size) { 133 /* Provide block_size/12 scaling */ 134 cinfo->jpeg_width = (JDIMENSION) 135 jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 12L); 136 cinfo->jpeg_height = (JDIMENSION) 137 jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 12L); 138 cinfo->min_DCT_h_scaled_size = 12; 139 cinfo->min_DCT_v_scaled_size = 12; 140 } else if (cinfo->scale_num * 13 >= cinfo->scale_denom * cinfo->block_size) { 141 /* Provide block_size/13 scaling */ 142 cinfo->jpeg_width = (JDIMENSION) 143 jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 13L); 144 cinfo->jpeg_height = (JDIMENSION) 145 jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 13L); 146 cinfo->min_DCT_h_scaled_size = 13; 147 cinfo->min_DCT_v_scaled_size = 13; 148 } else if (cinfo->scale_num * 14 >= cinfo->scale_denom * cinfo->block_size) { 149 /* Provide block_size/14 scaling */ 150 cinfo->jpeg_width = (JDIMENSION) 151 jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 14L); 152 cinfo->jpeg_height = (JDIMENSION) 153 jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 14L); 154 cinfo->min_DCT_h_scaled_size = 14; 155 cinfo->min_DCT_v_scaled_size = 14; 156 } else if (cinfo->scale_num * 15 >= cinfo->scale_denom * cinfo->block_size) { 157 /* Provide block_size/15 scaling */ 158 cinfo->jpeg_width = (JDIMENSION) 159 jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 15L); 160 cinfo->jpeg_height = (JDIMENSION) 161 jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 15L); 162 cinfo->min_DCT_h_scaled_size = 15; 163 cinfo->min_DCT_v_scaled_size = 15; 164 } else { 165 /* Provide block_size/16 scaling */ 166 cinfo->jpeg_width = (JDIMENSION) 167 jdiv_round_up((long) cinfo->image_width * cinfo->block_size, 16L); 168 cinfo->jpeg_height = (JDIMENSION) 169 jdiv_round_up((long) cinfo->image_height * cinfo->block_size, 16L); 170 cinfo->min_DCT_h_scaled_size = 16; 171 cinfo->min_DCT_v_scaled_size = 16; 172 } 173 174 #else /* !DCT_SCALING_SUPPORTED */ 175 176 /* Hardwire it to "no scaling" */ 177 cinfo->jpeg_width = cinfo->image_width; 178 cinfo->jpeg_height = cinfo->image_height; 179 cinfo->min_DCT_h_scaled_size = DCTSIZE; 180 cinfo->min_DCT_v_scaled_size = DCTSIZE; 181 182 #endif /* DCT_SCALING_SUPPORTED */ 183 } 184 185 186 /* 187 * Master selection of compression modules. 188 * This is done once at the start of processing an image. We determine 189 * which modules will be used and give them appropriate initialization calls. 190 */ 191 192 GLOBAL(void) 193 jinit_compress_master (j_compress_ptr cinfo) 194 { 195 long samplesperrow; 196 JDIMENSION jd_samplesperrow; 197 198 /* For now, precision must match compiled-in value... */ 199 if (cinfo->data_precision != BITS_IN_JSAMPLE) 200 ERREXIT1(cinfo, JERR_BAD_PRECISION, cinfo->data_precision); 201 202 /* Sanity check on input image dimensions */ 203 if (cinfo->image_height <= 0 || cinfo->image_width <= 0 || 204 cinfo->input_components <= 0) 205 ERREXIT(cinfo, JERR_EMPTY_IMAGE); 206 207 /* Width of an input scanline must be representable as JDIMENSION. */ 208 samplesperrow = (long) cinfo->image_width * (long) cinfo->input_components; 209 jd_samplesperrow = (JDIMENSION) samplesperrow; 210 if ((long) jd_samplesperrow != samplesperrow) 211 ERREXIT(cinfo, JERR_WIDTH_OVERFLOW); 212 213 /* Compute JPEG image dimensions and related values. */ 214 jpeg_calc_jpeg_dimensions(cinfo); 215 216 /* Initialize master control (includes parameter checking/processing) */ 217 jinit_c_master_control(cinfo, FALSE /* full compression */); 218 219 /* Preprocessing */ 220 if (! cinfo->raw_data_in) { 221 jinit_color_converter(cinfo); 222 jinit_downsampler(cinfo); 223 jinit_c_prep_controller(cinfo, FALSE /* never need full buffer here */); 224 } 225 /* Forward DCT */ 226 jinit_forward_dct(cinfo); 227 /* Entropy encoding: either Huffman or arithmetic coding. */ 228 if (cinfo->arith_code) 229 jinit_arith_encoder(cinfo); 230 else { 231 jinit_huff_encoder(cinfo); 232 } 233 234 /* Need a full-image coefficient buffer in any multi-pass mode. */ 235 jinit_c_coef_controller(cinfo, 236 (boolean) (cinfo->num_scans > 1 || cinfo->optimize_coding)); 237 jinit_c_main_controller(cinfo, FALSE /* never need full buffer here */); 238 239 jinit_marker_writer(cinfo); 240 241 /* We can now tell the memory manager to allocate virtual arrays. */ 242 (*cinfo->mem->realize_virt_arrays) ((j_common_ptr) cinfo); 243 244 /* Write the datastream header (SOI) immediately. 245 * Frame and scan headers are postponed till later. 246 * This lets application insert special markers after the SOI. 247 */ 248 (*cinfo->marker->write_file_header) (cinfo); 249 } 250