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