1 /* 2 * jddctmgr.c 3 * 4 * Copyright (C) 1994-1996, Thomas G. Lane. 5 * This file is part of the Independent JPEG Group's software. 6 * For conditions of distribution and use, see the accompanying README file. 7 * 8 * This file contains the inverse-DCT management logic. 9 * This code selects a particular IDCT implementation to be used, 10 * and it performs related housekeeping chores. No code in this file 11 * is executed per IDCT step, only during output pass setup. 12 * 13 * Note that the IDCT routines are responsible for performing coefficient 14 * dequantization as well as the IDCT proper. This module sets up the 15 * dequantization multiplier table needed by the IDCT routine. 16 */ 17 18 #define JPEG_INTERNALS 19 #include "jinclude.h" 20 #include "jpeglib.h" 21 #include "jdct.h" /* Private declarations for DCT subsystem */ 22 23 #ifdef ANDROID_ARMV6_IDCT 24 #undef ANDROID_ARMV6_IDCT 25 #ifdef __arm__ 26 #include <machine/cpu-features.h> 27 #if __ARM_ARCH__ >= 6 28 #define ANDROID_ARMV6_IDCT 29 #else 30 #warning "ANDROID_ARMV6_IDCT is disabled" 31 #endif 32 #endif 33 #endif 34 35 #ifdef ANDROID_ARMV6_IDCT 36 37 /* Intentionally declare the prototype with arguments of primitive types instead 38 * of type-defined ones. This will at least generate some warnings if jmorecfg.h 39 * is changed and becomes incompatible with the assembly code. 40 */ 41 extern void armv6_idct(short *coefs, int *quans, unsigned char **rows, int col); 42 43 void jpeg_idct_armv6 (j_decompress_ptr cinfo, jpeg_component_info * compptr, 44 JCOEFPTR coef_block, 45 JSAMPARRAY output_buf, JDIMENSION output_col) 46 { 47 IFAST_MULT_TYPE *dct_table = (IFAST_MULT_TYPE *)compptr->dct_table; 48 armv6_idct(coef_block, dct_table, output_buf, output_col); 49 } 50 51 #endif 52 53 #ifdef ANDROID_INTELSSE2_IDCT 54 extern short __attribute__((aligned(16))) quantptrSSE[DCTSIZE2]; 55 extern void jpeg_idct_intelsse (j_decompress_ptr cinfo, jpeg_component_info * compptr, 56 JCOEFPTR coef_block, 57 JSAMPARRAY output_buf, JDIMENSION output_col); 58 #endif 59 60 #ifdef ANDROID_MIPS_IDCT 61 extern void jpeg_idct_mips(j_decompress_ptr, jpeg_component_info *, JCOEFPTR, JSAMPARRAY, JDIMENSION); 62 #endif 63 64 /* 65 * The decompressor input side (jdinput.c) saves away the appropriate 66 * quantization table for each component at the start of the first scan 67 * involving that component. (This is necessary in order to correctly 68 * decode files that reuse Q-table slots.) 69 * When we are ready to make an output pass, the saved Q-table is converted 70 * to a multiplier table that will actually be used by the IDCT routine. 71 * The multiplier table contents are IDCT-method-dependent. To support 72 * application changes in IDCT method between scans, we can remake the 73 * multiplier tables if necessary. 74 * In buffered-image mode, the first output pass may occur before any data 75 * has been seen for some components, and thus before their Q-tables have 76 * been saved away. To handle this case, multiplier tables are preset 77 * to zeroes; the result of the IDCT will be a neutral gray level. 78 */ 79 80 81 /* Private subobject for this module */ 82 83 typedef struct { 84 struct jpeg_inverse_dct pub; /* public fields */ 85 86 /* This array contains the IDCT method code that each multiplier table 87 * is currently set up for, or -1 if it's not yet set up. 88 * The actual multiplier tables are pointed to by dct_table in the 89 * per-component comp_info structures. 90 */ 91 int cur_method[MAX_COMPONENTS]; 92 } my_idct_controller; 93 94 typedef my_idct_controller * my_idct_ptr; 95 96 97 /* Allocated multiplier tables: big enough for any supported variant */ 98 99 typedef union { 100 ISLOW_MULT_TYPE islow_array[DCTSIZE2]; 101 #ifdef DCT_IFAST_SUPPORTED 102 IFAST_MULT_TYPE ifast_array[DCTSIZE2]; 103 #endif 104 #ifdef DCT_FLOAT_SUPPORTED 105 FLOAT_MULT_TYPE float_array[DCTSIZE2]; 106 #endif 107 } multiplier_table; 108 109 110 /* The current scaled-IDCT routines require ISLOW-style multiplier tables, 111 * so be sure to compile that code if either ISLOW or SCALING is requested. 112 */ 113 #ifdef DCT_ISLOW_SUPPORTED 114 #define PROVIDE_ISLOW_TABLES 115 #else 116 #ifdef IDCT_SCALING_SUPPORTED 117 #define PROVIDE_ISLOW_TABLES 118 #endif 119 #endif 120 121 122 /* 123 * Prepare for an output pass. 124 * Here we select the proper IDCT routine for each component and build 125 * a matching multiplier table. 126 */ 127 128 METHODDEF(void) 129 start_pass (j_decompress_ptr cinfo) 130 { 131 my_idct_ptr idct = (my_idct_ptr) cinfo->idct; 132 int ci, i; 133 jpeg_component_info *compptr; 134 int method = 0; 135 inverse_DCT_method_ptr method_ptr = NULL; 136 JQUANT_TBL * qtbl; 137 138 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; 139 ci++, compptr++) { 140 /* Select the proper IDCT routine for this component's scaling */ 141 switch (compptr->DCT_scaled_size) { 142 #ifdef IDCT_SCALING_SUPPORTED 143 case 1: 144 method_ptr = jpeg_idct_1x1; 145 method = JDCT_ISLOW; /* jidctred uses islow-style table */ 146 break; 147 case 2: 148 method_ptr = jpeg_idct_2x2; 149 method = JDCT_ISLOW; /* jidctred uses islow-style table */ 150 break; 151 case 4: 152 method_ptr = jpeg_idct_4x4; 153 method = JDCT_ISLOW; /* jidctred uses islow-style table */ 154 break; 155 #endif 156 case DCTSIZE: 157 switch (cinfo->dct_method) { 158 #ifdef ANDROID_ARMV6_IDCT 159 case JDCT_ISLOW: 160 case JDCT_IFAST: 161 method_ptr = jpeg_idct_armv6; 162 method = JDCT_IFAST; 163 break; 164 #else /* ANDROID_ARMV6_IDCT */ 165 #ifdef ANDROID_INTELSSE2_IDCT 166 case JDCT_ISLOW: 167 case JDCT_IFAST: 168 method_ptr = jpeg_idct_intelsse; 169 method = JDCT_ISLOW; /* Use quant table of ISLOW.*/ 170 break; 171 #else /* ANDROID_INTELSSE2_IDCT */ 172 #ifdef ANDROID_MIPS_IDCT 173 case JDCT_ISLOW: 174 case JDCT_IFAST: 175 method_ptr = jpeg_idct_mips; 176 method = JDCT_IFAST; 177 break; 178 #else /* ANDROID_MIPS_IDCT */ 179 #ifdef DCT_ISLOW_SUPPORTED 180 case JDCT_ISLOW: 181 method_ptr = jpeg_idct_islow; 182 method = JDCT_ISLOW; 183 break; 184 #endif 185 #ifdef DCT_IFAST_SUPPORTED 186 case JDCT_IFAST: 187 method_ptr = jpeg_idct_ifast; 188 method = JDCT_IFAST; 189 break; 190 #endif 191 #endif /* ANDROID_MIPS_IDCT */ 192 #endif /* ANDROID_INTELSSE2_IDCT*/ 193 #endif /* ANDROID_ARMV6_IDCT */ 194 #ifdef DCT_FLOAT_SUPPORTED 195 case JDCT_FLOAT: 196 method_ptr = jpeg_idct_float; 197 method = JDCT_FLOAT; 198 break; 199 #endif 200 default: 201 ERREXIT(cinfo, JERR_NOT_COMPILED); 202 break; 203 } 204 break; 205 default: 206 ERREXIT1(cinfo, JERR_BAD_DCTSIZE, compptr->DCT_scaled_size); 207 break; 208 } 209 idct->pub.inverse_DCT[ci] = method_ptr; 210 /* Create multiplier table from quant table. 211 * However, we can skip this if the component is uninteresting 212 * or if we already built the table. Also, if no quant table 213 * has yet been saved for the component, we leave the 214 * multiplier table all-zero; we'll be reading zeroes from the 215 * coefficient controller's buffer anyway. 216 */ 217 if (! compptr->component_needed || idct->cur_method[ci] == method) 218 continue; 219 qtbl = compptr->quant_table; 220 if (qtbl == NULL) /* happens if no data yet for component */ 221 continue; 222 idct->cur_method[ci] = method; 223 switch (method) { 224 #ifdef PROVIDE_ISLOW_TABLES 225 case JDCT_ISLOW: 226 { 227 /* For LL&M IDCT method, multipliers are equal to raw quantization 228 * coefficients, but are stored as ints to ensure access efficiency. 229 */ 230 ISLOW_MULT_TYPE * ismtbl = (ISLOW_MULT_TYPE *) compptr->dct_table; 231 for (i = 0; i < DCTSIZE2; i++) { 232 ismtbl[i] = (ISLOW_MULT_TYPE) qtbl->quantval[i]; 233 } 234 } 235 break; 236 #endif 237 #ifdef DCT_IFAST_SUPPORTED 238 case JDCT_IFAST: 239 { 240 /* For AA&N IDCT method, multipliers are equal to quantization 241 * coefficients scaled by scalefactor[row]*scalefactor[col], where 242 * scalefactor[0] = 1 243 * scalefactor[k] = cos(k*PI/16) * sqrt(2) for k=1..7 244 * For integer operation, the multiplier table is to be scaled by 245 * IFAST_SCALE_BITS. 246 */ 247 IFAST_MULT_TYPE * ifmtbl = (IFAST_MULT_TYPE *) compptr->dct_table; 248 #ifdef ANDROID_ARMV6_IDCT 249 /* Precomputed values scaled up by 15 bits. */ 250 static const unsigned short scales[DCTSIZE2] = { 251 32768, 45451, 42813, 38531, 32768, 25746, 17734, 9041, 252 45451, 63042, 59384, 53444, 45451, 35710, 24598, 12540, 253 42813, 59384, 55938, 50343, 42813, 33638, 23170, 11812, 254 38531, 53444, 50343, 45308, 38531, 30274, 20853, 10631, 255 32768, 45451, 42813, 38531, 32768, 25746, 17734, 9041, 256 25746, 35710, 33638, 30274, 25746, 20228, 13933, 7103, 257 17734, 24598, 23170, 20853, 17734, 13933, 9598, 4893, 258 9041, 12540, 11812, 10631, 9041, 7103, 4893, 2494, 259 }; 260 /* Inverse map of [7, 5, 1, 3, 0, 2, 4, 6]. */ 261 static const char orders[DCTSIZE] = {4, 2, 5, 3, 6, 1, 7, 0}; 262 /* Reorder the columns after transposing. */ 263 for (i = 0; i < DCTSIZE2; ++i) { 264 int j = ((i & 7) << 3) + orders[i >> 3]; 265 ifmtbl[j] = (qtbl->quantval[i] * scales[i] + 2) >> 2; 266 } 267 #else /* ANDROID_ARMV6_IDCT */ 268 269 #define CONST_BITS 14 270 static const INT16 aanscales[DCTSIZE2] = { 271 /* precomputed values scaled up by 14 bits */ 272 16384, 22725, 21407, 19266, 16384, 12873, 8867, 4520, 273 22725, 31521, 29692, 26722, 22725, 17855, 12299, 6270, 274 21407, 29692, 27969, 25172, 21407, 16819, 11585, 5906, 275 19266, 26722, 25172, 22654, 19266, 15137, 10426, 5315, 276 16384, 22725, 21407, 19266, 16384, 12873, 8867, 4520, 277 12873, 17855, 16819, 15137, 12873, 10114, 6967, 3552, 278 8867, 12299, 11585, 10426, 8867, 6967, 4799, 2446, 279 4520, 6270, 5906, 5315, 4520, 3552, 2446, 1247 280 }; 281 SHIFT_TEMPS 282 283 for (i = 0; i < DCTSIZE2; i++) { 284 ifmtbl[i] = (IFAST_MULT_TYPE) 285 DESCALE(MULTIPLY16V16((INT32) qtbl->quantval[i], 286 (INT32) aanscales[i]), 287 CONST_BITS-IFAST_SCALE_BITS); 288 } 289 #endif /* ANDROID_ARMV6_IDCT */ 290 } 291 break; 292 #endif 293 #ifdef DCT_FLOAT_SUPPORTED 294 case JDCT_FLOAT: 295 { 296 /* For float AA&N IDCT method, multipliers are equal to quantization 297 * coefficients scaled by scalefactor[row]*scalefactor[col], where 298 * scalefactor[0] = 1 299 * scalefactor[k] = cos(k*PI/16) * sqrt(2) for k=1..7 300 */ 301 FLOAT_MULT_TYPE * fmtbl = (FLOAT_MULT_TYPE *) compptr->dct_table; 302 int row, col; 303 static const double aanscalefactor[DCTSIZE] = { 304 1.0, 1.387039845, 1.306562965, 1.175875602, 305 1.0, 0.785694958, 0.541196100, 0.275899379 306 }; 307 308 i = 0; 309 for (row = 0; row < DCTSIZE; row++) { 310 for (col = 0; col < DCTSIZE; col++) { 311 fmtbl[i] = (FLOAT_MULT_TYPE) 312 ((double) qtbl->quantval[i] * 313 aanscalefactor[row] * aanscalefactor[col]); 314 i++; 315 } 316 } 317 } 318 break; 319 #endif 320 default: 321 ERREXIT(cinfo, JERR_NOT_COMPILED); 322 break; 323 } 324 } 325 } 326 327 328 /* 329 * Initialize IDCT manager. 330 */ 331 332 GLOBAL(void) 333 jinit_inverse_dct (j_decompress_ptr cinfo) 334 { 335 my_idct_ptr idct; 336 int ci; 337 jpeg_component_info *compptr; 338 339 idct = (my_idct_ptr) 340 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, 341 SIZEOF(my_idct_controller)); 342 cinfo->idct = (struct jpeg_inverse_dct *) idct; 343 idct->pub.start_pass = start_pass; 344 345 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; 346 ci++, compptr++) { 347 /* Allocate and pre-zero a multiplier table for each component */ 348 compptr->dct_table = 349 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, 350 SIZEOF(multiplier_table)); 351 MEMZERO(compptr->dct_table, SIZEOF(multiplier_table)); 352 /* Mark multiplier table not yet set up for any method */ 353 idct->cur_method[ci] = -1; 354 } 355 } 356
