Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 1 | /* |
| 2 | * jcdctmgr.c |
| 3 | * |
DRC | a73e870 | 2012-12-31 02:52:30 +0000 | [diff] [blame] | 4 | * This file was part of the Independent JPEG Group's software: |
Thomas G. Lane | 489583f | 1996-02-07 00:00:00 +0000 | [diff] [blame] | 5 | * Copyright (C) 1994-1996, Thomas G. Lane. |
DRC | a6ef282 | 2013-09-28 03:23:49 +0000 | [diff] [blame^] | 6 | * libjpeg-turbo Modifications: |
Pierre Ossman | dedc42e | 2009-03-09 13:23:04 +0000 | [diff] [blame] | 7 | * Copyright (C) 1999-2006, MIYASAKA Masaru. |
Pierre Ossman | 59a3938 | 2009-03-09 13:15:56 +0000 | [diff] [blame] | 8 | * Copyright 2009 Pierre Ossman <ossman@cendio.se> for Cendio AB |
DRC | a49c4e5 | 2011-02-18 20:50:08 +0000 | [diff] [blame] | 9 | * Copyright (C) 2011 D. R. Commander |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 10 | * For conditions of distribution and use, see the accompanying README file. |
| 11 | * |
| 12 | * This file contains the forward-DCT management logic. |
| 13 | * This code selects a particular DCT implementation to be used, |
| 14 | * and it performs related housekeeping chores including coefficient |
| 15 | * quantization. |
| 16 | */ |
| 17 | |
| 18 | #define JPEG_INTERNALS |
| 19 | #include "jinclude.h" |
| 20 | #include "jpeglib.h" |
| 21 | #include "jdct.h" /* Private declarations for DCT subsystem */ |
Pierre Ossman | 59a3938 | 2009-03-09 13:15:56 +0000 | [diff] [blame] | 22 | #include "jsimddct.h" |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 23 | |
| 24 | |
| 25 | /* Private subobject for this module */ |
| 26 | |
Pierre Ossman | 49dcbfb | 2009-03-09 10:37:20 +0000 | [diff] [blame] | 27 | typedef JMETHOD(void, forward_DCT_method_ptr, (DCTELEM * data)); |
| 28 | typedef JMETHOD(void, float_DCT_method_ptr, (FAST_FLOAT * data)); |
| 29 | |
| 30 | typedef JMETHOD(void, convsamp_method_ptr, |
| 31 | (JSAMPARRAY sample_data, JDIMENSION start_col, |
| 32 | DCTELEM * workspace)); |
| 33 | typedef JMETHOD(void, float_convsamp_method_ptr, |
| 34 | (JSAMPARRAY sample_data, JDIMENSION start_col, |
| 35 | FAST_FLOAT *workspace)); |
| 36 | |
| 37 | typedef JMETHOD(void, quantize_method_ptr, |
| 38 | (JCOEFPTR coef_block, DCTELEM * divisors, |
| 39 | DCTELEM * workspace)); |
| 40 | typedef JMETHOD(void, float_quantize_method_ptr, |
| 41 | (JCOEFPTR coef_block, FAST_FLOAT * divisors, |
| 42 | FAST_FLOAT * workspace)); |
| 43 | |
DRC | a49c4e5 | 2011-02-18 20:50:08 +0000 | [diff] [blame] | 44 | METHODDEF(void) quantize (JCOEFPTR, DCTELEM *, DCTELEM *); |
| 45 | |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 46 | typedef struct { |
| 47 | struct jpeg_forward_dct pub; /* public fields */ |
| 48 | |
| 49 | /* Pointer to the DCT routine actually in use */ |
Pierre Ossman | 49dcbfb | 2009-03-09 10:37:20 +0000 | [diff] [blame] | 50 | forward_DCT_method_ptr dct; |
| 51 | convsamp_method_ptr convsamp; |
| 52 | quantize_method_ptr quantize; |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 53 | |
| 54 | /* The actual post-DCT divisors --- not identical to the quant table |
| 55 | * entries, because of scaling (especially for an unnormalized DCT). |
Thomas G. Lane | 489583f | 1996-02-07 00:00:00 +0000 | [diff] [blame] | 56 | * Each table is given in normal array order. |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 57 | */ |
| 58 | DCTELEM * divisors[NUM_QUANT_TBLS]; |
| 59 | |
Pierre Ossman | 35c4719 | 2009-03-09 13:29:37 +0000 | [diff] [blame] | 60 | /* work area for FDCT subroutine */ |
| 61 | DCTELEM * workspace; |
| 62 | |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 63 | #ifdef DCT_FLOAT_SUPPORTED |
| 64 | /* Same as above for the floating-point case. */ |
Pierre Ossman | 49dcbfb | 2009-03-09 10:37:20 +0000 | [diff] [blame] | 65 | float_DCT_method_ptr float_dct; |
| 66 | float_convsamp_method_ptr float_convsamp; |
| 67 | float_quantize_method_ptr float_quantize; |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 68 | FAST_FLOAT * float_divisors[NUM_QUANT_TBLS]; |
Pierre Ossman | 35c4719 | 2009-03-09 13:29:37 +0000 | [diff] [blame] | 69 | FAST_FLOAT * float_workspace; |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 70 | #endif |
| 71 | } my_fdct_controller; |
| 72 | |
| 73 | typedef my_fdct_controller * my_fdct_ptr; |
| 74 | |
| 75 | |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 76 | /* |
Pierre Ossman | dedc42e | 2009-03-09 13:23:04 +0000 | [diff] [blame] | 77 | * Find the highest bit in an integer through binary search. |
| 78 | */ |
| 79 | LOCAL(int) |
DRC | fc5dc4f | 2009-10-01 22:26:14 +0000 | [diff] [blame] | 80 | flss (UINT16 val) |
Pierre Ossman | dedc42e | 2009-03-09 13:23:04 +0000 | [diff] [blame] | 81 | { |
| 82 | int bit; |
| 83 | |
| 84 | bit = 16; |
| 85 | |
| 86 | if (!val) |
| 87 | return 0; |
| 88 | |
| 89 | if (!(val & 0xff00)) { |
| 90 | bit -= 8; |
| 91 | val <<= 8; |
| 92 | } |
| 93 | if (!(val & 0xf000)) { |
| 94 | bit -= 4; |
| 95 | val <<= 4; |
| 96 | } |
| 97 | if (!(val & 0xc000)) { |
| 98 | bit -= 2; |
| 99 | val <<= 2; |
| 100 | } |
| 101 | if (!(val & 0x8000)) { |
| 102 | bit -= 1; |
| 103 | val <<= 1; |
| 104 | } |
| 105 | |
| 106 | return bit; |
| 107 | } |
| 108 | |
| 109 | /* |
| 110 | * Compute values to do a division using reciprocal. |
| 111 | * |
| 112 | * This implementation is based on an algorithm described in |
| 113 | * "How to optimize for the Pentium family of microprocessors" |
| 114 | * (http://www.agner.org/assem/). |
| 115 | * More information about the basic algorithm can be found in |
| 116 | * the paper "Integer Division Using Reciprocals" by Robert Alverson. |
| 117 | * |
| 118 | * The basic idea is to replace x/d by x * d^-1. In order to store |
| 119 | * d^-1 with enough precision we shift it left a few places. It turns |
| 120 | * out that this algoright gives just enough precision, and also fits |
| 121 | * into DCTELEM: |
| 122 | * |
| 123 | * b = (the number of significant bits in divisor) - 1 |
| 124 | * r = (word size) + b |
| 125 | * f = 2^r / divisor |
| 126 | * |
| 127 | * f will not be an integer for most cases, so we need to compensate |
| 128 | * for the rounding error introduced: |
| 129 | * |
| 130 | * no fractional part: |
| 131 | * |
| 132 | * result = input >> r |
| 133 | * |
| 134 | * fractional part of f < 0.5: |
| 135 | * |
| 136 | * round f down to nearest integer |
| 137 | * result = ((input + 1) * f) >> r |
| 138 | * |
| 139 | * fractional part of f > 0.5: |
| 140 | * |
| 141 | * round f up to nearest integer |
| 142 | * result = (input * f) >> r |
| 143 | * |
| 144 | * This is the original algorithm that gives truncated results. But we |
| 145 | * want properly rounded results, so we replace "input" with |
| 146 | * "input + divisor/2". |
| 147 | * |
| 148 | * In order to allow SIMD implementations we also tweak the values to |
| 149 | * allow the same calculation to be made at all times: |
| 150 | * |
| 151 | * dctbl[0] = f rounded to nearest integer |
| 152 | * dctbl[1] = divisor / 2 (+ 1 if fractional part of f < 0.5) |
| 153 | * dctbl[2] = 1 << ((word size) * 2 - r) |
| 154 | * dctbl[3] = r - (word size) |
| 155 | * |
| 156 | * dctbl[2] is for stupid instruction sets where the shift operation |
| 157 | * isn't member wise (e.g. MMX). |
| 158 | * |
| 159 | * The reason dctbl[2] and dctbl[3] reduce the shift with (word size) |
| 160 | * is that most SIMD implementations have a "multiply and store top |
| 161 | * half" operation. |
| 162 | * |
| 163 | * Lastly, we store each of the values in their own table instead |
| 164 | * of in a consecutive manner, yet again in order to allow SIMD |
| 165 | * routines. |
| 166 | */ |
DRC | a49c4e5 | 2011-02-18 20:50:08 +0000 | [diff] [blame] | 167 | LOCAL(int) |
Pierre Ossman | dedc42e | 2009-03-09 13:23:04 +0000 | [diff] [blame] | 168 | compute_reciprocal (UINT16 divisor, DCTELEM * dtbl) |
| 169 | { |
| 170 | UDCTELEM2 fq, fr; |
| 171 | UDCTELEM c; |
| 172 | int b, r; |
| 173 | |
DRC | fc5dc4f | 2009-10-01 22:26:14 +0000 | [diff] [blame] | 174 | b = flss(divisor) - 1; |
Pierre Ossman | dedc42e | 2009-03-09 13:23:04 +0000 | [diff] [blame] | 175 | r = sizeof(DCTELEM) * 8 + b; |
| 176 | |
| 177 | fq = ((UDCTELEM2)1 << r) / divisor; |
| 178 | fr = ((UDCTELEM2)1 << r) % divisor; |
| 179 | |
| 180 | c = divisor / 2; /* for rounding */ |
| 181 | |
| 182 | if (fr == 0) { /* divisor is power of two */ |
| 183 | /* fq will be one bit too large to fit in DCTELEM, so adjust */ |
| 184 | fq >>= 1; |
| 185 | r--; |
DRC | d65d99a | 2012-01-31 03:39:23 +0000 | [diff] [blame] | 186 | } else if (fr <= (divisor / 2U)) { /* fractional part is < 0.5 */ |
Pierre Ossman | dedc42e | 2009-03-09 13:23:04 +0000 | [diff] [blame] | 187 | c++; |
| 188 | } else { /* fractional part is > 0.5 */ |
| 189 | fq++; |
| 190 | } |
| 191 | |
| 192 | dtbl[DCTSIZE2 * 0] = (DCTELEM) fq; /* reciprocal */ |
| 193 | dtbl[DCTSIZE2 * 1] = (DCTELEM) c; /* correction + roundfactor */ |
| 194 | dtbl[DCTSIZE2 * 2] = (DCTELEM) (1 << (sizeof(DCTELEM)*8*2 - r)); /* scale */ |
| 195 | dtbl[DCTSIZE2 * 3] = (DCTELEM) r - sizeof(DCTELEM)*8; /* shift */ |
DRC | a49c4e5 | 2011-02-18 20:50:08 +0000 | [diff] [blame] | 196 | |
| 197 | if(r <= 16) return 0; |
| 198 | else return 1; |
Pierre Ossman | dedc42e | 2009-03-09 13:23:04 +0000 | [diff] [blame] | 199 | } |
| 200 | |
| 201 | /* |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 202 | * Initialize for a processing pass. |
| 203 | * Verify that all referenced Q-tables are present, and set up |
| 204 | * the divisor table for each one. |
| 205 | * In the current implementation, DCT of all components is done during |
| 206 | * the first pass, even if only some components will be output in the |
| 207 | * first scan. Hence all components should be examined here. |
| 208 | */ |
| 209 | |
Thomas G. Lane | 489583f | 1996-02-07 00:00:00 +0000 | [diff] [blame] | 210 | METHODDEF(void) |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 211 | start_pass_fdctmgr (j_compress_ptr cinfo) |
| 212 | { |
| 213 | my_fdct_ptr fdct = (my_fdct_ptr) cinfo->fdct; |
| 214 | int ci, qtblno, i; |
| 215 | jpeg_component_info *compptr; |
| 216 | JQUANT_TBL * qtbl; |
| 217 | DCTELEM * dtbl; |
| 218 | |
| 219 | for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; |
| 220 | ci++, compptr++) { |
| 221 | qtblno = compptr->quant_tbl_no; |
| 222 | /* Make sure specified quantization table is present */ |
| 223 | if (qtblno < 0 || qtblno >= NUM_QUANT_TBLS || |
| 224 | cinfo->quant_tbl_ptrs[qtblno] == NULL) |
| 225 | ERREXIT1(cinfo, JERR_NO_QUANT_TABLE, qtblno); |
| 226 | qtbl = cinfo->quant_tbl_ptrs[qtblno]; |
| 227 | /* Compute divisors for this quant table */ |
| 228 | /* We may do this more than once for same table, but it's not a big deal */ |
| 229 | switch (cinfo->dct_method) { |
| 230 | #ifdef DCT_ISLOW_SUPPORTED |
| 231 | case JDCT_ISLOW: |
| 232 | /* For LL&M IDCT method, divisors are equal to raw quantization |
| 233 | * coefficients multiplied by 8 (to counteract scaling). |
| 234 | */ |
| 235 | if (fdct->divisors[qtblno] == NULL) { |
| 236 | fdct->divisors[qtblno] = (DCTELEM *) |
| 237 | (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, |
Pierre Ossman | dedc42e | 2009-03-09 13:23:04 +0000 | [diff] [blame] | 238 | (DCTSIZE2 * 4) * SIZEOF(DCTELEM)); |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 239 | } |
| 240 | dtbl = fdct->divisors[qtblno]; |
| 241 | for (i = 0; i < DCTSIZE2; i++) { |
DRC | a49c4e5 | 2011-02-18 20:50:08 +0000 | [diff] [blame] | 242 | if(!compute_reciprocal(qtbl->quantval[i] << 3, &dtbl[i]) |
| 243 | && fdct->quantize == jsimd_quantize) |
| 244 | fdct->quantize = quantize; |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 245 | } |
| 246 | break; |
| 247 | #endif |
| 248 | #ifdef DCT_IFAST_SUPPORTED |
| 249 | case JDCT_IFAST: |
| 250 | { |
| 251 | /* For AA&N IDCT method, divisors are equal to quantization |
| 252 | * coefficients scaled by scalefactor[row]*scalefactor[col], where |
| 253 | * scalefactor[0] = 1 |
| 254 | * scalefactor[k] = cos(k*PI/16) * sqrt(2) for k=1..7 |
| 255 | * We apply a further scale factor of 8. |
| 256 | */ |
| 257 | #define CONST_BITS 14 |
| 258 | static const INT16 aanscales[DCTSIZE2] = { |
Thomas G. Lane | 489583f | 1996-02-07 00:00:00 +0000 | [diff] [blame] | 259 | /* precomputed values scaled up by 14 bits */ |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 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 | if (fdct->divisors[qtblno] == NULL) { |
| 272 | fdct->divisors[qtblno] = (DCTELEM *) |
| 273 | (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, |
Pierre Ossman | dedc42e | 2009-03-09 13:23:04 +0000 | [diff] [blame] | 274 | (DCTSIZE2 * 4) * SIZEOF(DCTELEM)); |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 275 | } |
| 276 | dtbl = fdct->divisors[qtblno]; |
| 277 | for (i = 0; i < DCTSIZE2; i++) { |
DRC | a49c4e5 | 2011-02-18 20:50:08 +0000 | [diff] [blame] | 278 | if(!compute_reciprocal( |
Thomas G. Lane | 489583f | 1996-02-07 00:00:00 +0000 | [diff] [blame] | 279 | DESCALE(MULTIPLY16V16((INT32) qtbl->quantval[i], |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 280 | (INT32) aanscales[i]), |
DRC | a49c4e5 | 2011-02-18 20:50:08 +0000 | [diff] [blame] | 281 | CONST_BITS-3), &dtbl[i]) |
| 282 | && fdct->quantize == jsimd_quantize) |
| 283 | fdct->quantize = quantize; |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 284 | } |
| 285 | } |
| 286 | break; |
| 287 | #endif |
| 288 | #ifdef DCT_FLOAT_SUPPORTED |
| 289 | case JDCT_FLOAT: |
| 290 | { |
| 291 | /* For float AA&N IDCT method, divisors are equal to quantization |
| 292 | * coefficients scaled by scalefactor[row]*scalefactor[col], where |
| 293 | * scalefactor[0] = 1 |
| 294 | * scalefactor[k] = cos(k*PI/16) * sqrt(2) for k=1..7 |
| 295 | * We apply a further scale factor of 8. |
| 296 | * What's actually stored is 1/divisor so that the inner loop can |
| 297 | * use a multiplication rather than a division. |
| 298 | */ |
| 299 | FAST_FLOAT * fdtbl; |
| 300 | int row, col; |
| 301 | static const double aanscalefactor[DCTSIZE] = { |
| 302 | 1.0, 1.387039845, 1.306562965, 1.175875602, |
| 303 | 1.0, 0.785694958, 0.541196100, 0.275899379 |
| 304 | }; |
| 305 | |
| 306 | if (fdct->float_divisors[qtblno] == NULL) { |
| 307 | fdct->float_divisors[qtblno] = (FAST_FLOAT *) |
| 308 | (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, |
| 309 | DCTSIZE2 * SIZEOF(FAST_FLOAT)); |
| 310 | } |
| 311 | fdtbl = fdct->float_divisors[qtblno]; |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 312 | i = 0; |
| 313 | for (row = 0; row < DCTSIZE; row++) { |
| 314 | for (col = 0; col < DCTSIZE; col++) { |
| 315 | fdtbl[i] = (FAST_FLOAT) |
Thomas G. Lane | 489583f | 1996-02-07 00:00:00 +0000 | [diff] [blame] | 316 | (1.0 / (((double) qtbl->quantval[i] * |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 317 | aanscalefactor[row] * aanscalefactor[col] * 8.0))); |
| 318 | i++; |
| 319 | } |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 320 | } |
| 321 | } |
| 322 | break; |
| 323 | #endif |
| 324 | default: |
| 325 | ERREXIT(cinfo, JERR_NOT_COMPILED); |
| 326 | break; |
| 327 | } |
| 328 | } |
| 329 | } |
| 330 | |
| 331 | |
| 332 | /* |
Pierre Ossman | 49dcbfb | 2009-03-09 10:37:20 +0000 | [diff] [blame] | 333 | * Load data into workspace, applying unsigned->signed conversion. |
| 334 | */ |
| 335 | |
| 336 | METHODDEF(void) |
| 337 | convsamp (JSAMPARRAY sample_data, JDIMENSION start_col, DCTELEM * workspace) |
| 338 | { |
| 339 | register DCTELEM *workspaceptr; |
| 340 | register JSAMPROW elemptr; |
| 341 | register int elemr; |
| 342 | |
| 343 | workspaceptr = workspace; |
| 344 | for (elemr = 0; elemr < DCTSIZE; elemr++) { |
| 345 | elemptr = sample_data[elemr] + start_col; |
| 346 | |
| 347 | #if DCTSIZE == 8 /* unroll the inner loop */ |
| 348 | *workspaceptr++ = GETJSAMPLE(*elemptr++) - CENTERJSAMPLE; |
| 349 | *workspaceptr++ = GETJSAMPLE(*elemptr++) - CENTERJSAMPLE; |
| 350 | *workspaceptr++ = GETJSAMPLE(*elemptr++) - CENTERJSAMPLE; |
| 351 | *workspaceptr++ = GETJSAMPLE(*elemptr++) - CENTERJSAMPLE; |
| 352 | *workspaceptr++ = GETJSAMPLE(*elemptr++) - CENTERJSAMPLE; |
| 353 | *workspaceptr++ = GETJSAMPLE(*elemptr++) - CENTERJSAMPLE; |
| 354 | *workspaceptr++ = GETJSAMPLE(*elemptr++) - CENTERJSAMPLE; |
| 355 | *workspaceptr++ = GETJSAMPLE(*elemptr++) - CENTERJSAMPLE; |
| 356 | #else |
| 357 | { |
| 358 | register int elemc; |
| 359 | for (elemc = DCTSIZE; elemc > 0; elemc--) |
| 360 | *workspaceptr++ = GETJSAMPLE(*elemptr++) - CENTERJSAMPLE; |
| 361 | } |
| 362 | #endif |
| 363 | } |
| 364 | } |
| 365 | |
| 366 | |
| 367 | /* |
| 368 | * Quantize/descale the coefficients, and store into coef_blocks[]. |
| 369 | */ |
| 370 | |
| 371 | METHODDEF(void) |
| 372 | quantize (JCOEFPTR coef_block, DCTELEM * divisors, DCTELEM * workspace) |
| 373 | { |
Pierre Ossman | dedc42e | 2009-03-09 13:23:04 +0000 | [diff] [blame] | 374 | int i; |
| 375 | DCTELEM temp; |
| 376 | UDCTELEM recip, corr, shift; |
| 377 | UDCTELEM2 product; |
| 378 | JCOEFPTR output_ptr = coef_block; |
Pierre Ossman | 49dcbfb | 2009-03-09 10:37:20 +0000 | [diff] [blame] | 379 | |
| 380 | for (i = 0; i < DCTSIZE2; i++) { |
Pierre Ossman | 49dcbfb | 2009-03-09 10:37:20 +0000 | [diff] [blame] | 381 | temp = workspace[i]; |
Pierre Ossman | dedc42e | 2009-03-09 13:23:04 +0000 | [diff] [blame] | 382 | recip = divisors[i + DCTSIZE2 * 0]; |
| 383 | corr = divisors[i + DCTSIZE2 * 1]; |
| 384 | shift = divisors[i + DCTSIZE2 * 3]; |
Pierre Ossman | 49dcbfb | 2009-03-09 10:37:20 +0000 | [diff] [blame] | 385 | |
| 386 | if (temp < 0) { |
| 387 | temp = -temp; |
Pierre Ossman | dedc42e | 2009-03-09 13:23:04 +0000 | [diff] [blame] | 388 | product = (UDCTELEM2)(temp + corr) * recip; |
| 389 | product >>= shift + sizeof(DCTELEM)*8; |
| 390 | temp = product; |
Pierre Ossman | 49dcbfb | 2009-03-09 10:37:20 +0000 | [diff] [blame] | 391 | temp = -temp; |
| 392 | } else { |
Pierre Ossman | dedc42e | 2009-03-09 13:23:04 +0000 | [diff] [blame] | 393 | product = (UDCTELEM2)(temp + corr) * recip; |
| 394 | product >>= shift + sizeof(DCTELEM)*8; |
| 395 | temp = product; |
Pierre Ossman | 49dcbfb | 2009-03-09 10:37:20 +0000 | [diff] [blame] | 396 | } |
Pierre Ossman | dedc42e | 2009-03-09 13:23:04 +0000 | [diff] [blame] | 397 | |
Pierre Ossman | 49dcbfb | 2009-03-09 10:37:20 +0000 | [diff] [blame] | 398 | output_ptr[i] = (JCOEF) temp; |
| 399 | } |
| 400 | } |
| 401 | |
| 402 | |
| 403 | /* |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 404 | * Perform forward DCT on one or more blocks of a component. |
| 405 | * |
| 406 | * The input samples are taken from the sample_data[] array starting at |
| 407 | * position start_row/start_col, and moving to the right for any additional |
Thomas G. Lane | bc79e06 | 1995-08-02 00:00:00 +0000 | [diff] [blame] | 408 | * blocks. The quantized coefficients are returned in coef_blocks[]. |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 409 | */ |
| 410 | |
Thomas G. Lane | 489583f | 1996-02-07 00:00:00 +0000 | [diff] [blame] | 411 | METHODDEF(void) |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 412 | forward_DCT (j_compress_ptr cinfo, jpeg_component_info * compptr, |
| 413 | JSAMPARRAY sample_data, JBLOCKROW coef_blocks, |
| 414 | JDIMENSION start_row, JDIMENSION start_col, |
| 415 | JDIMENSION num_blocks) |
| 416 | /* This version is used for integer DCT implementations. */ |
| 417 | { |
| 418 | /* This routine is heavily used, so it's worth coding it tightly. */ |
| 419 | my_fdct_ptr fdct = (my_fdct_ptr) cinfo->fdct; |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 420 | DCTELEM * divisors = fdct->divisors[compptr->quant_tbl_no]; |
Pierre Ossman | 35c4719 | 2009-03-09 13:29:37 +0000 | [diff] [blame] | 421 | DCTELEM * workspace; |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 422 | JDIMENSION bi; |
| 423 | |
Pierre Ossman | 49dcbfb | 2009-03-09 10:37:20 +0000 | [diff] [blame] | 424 | /* Make sure the compiler doesn't look up these every pass */ |
| 425 | forward_DCT_method_ptr do_dct = fdct->dct; |
| 426 | convsamp_method_ptr do_convsamp = fdct->convsamp; |
| 427 | quantize_method_ptr do_quantize = fdct->quantize; |
Pierre Ossman | dc5db14 | 2009-03-13 12:17:26 +0000 | [diff] [blame] | 428 | workspace = fdct->workspace; |
Pierre Ossman | 49dcbfb | 2009-03-09 10:37:20 +0000 | [diff] [blame] | 429 | |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 430 | sample_data += start_row; /* fold in the vertical offset once */ |
| 431 | |
| 432 | for (bi = 0; bi < num_blocks; bi++, start_col += DCTSIZE) { |
| 433 | /* Load data into workspace, applying unsigned->signed conversion */ |
Pierre Ossman | 49dcbfb | 2009-03-09 10:37:20 +0000 | [diff] [blame] | 434 | (*do_convsamp) (sample_data, start_col, workspace); |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 435 | |
| 436 | /* Perform the DCT */ |
| 437 | (*do_dct) (workspace); |
| 438 | |
| 439 | /* Quantize/descale the coefficients, and store into coef_blocks[] */ |
Pierre Ossman | 49dcbfb | 2009-03-09 10:37:20 +0000 | [diff] [blame] | 440 | (*do_quantize) (coef_blocks[bi], divisors, workspace); |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 441 | } |
| 442 | } |
| 443 | |
| 444 | |
| 445 | #ifdef DCT_FLOAT_SUPPORTED |
| 446 | |
Pierre Ossman | 49dcbfb | 2009-03-09 10:37:20 +0000 | [diff] [blame] | 447 | |
| 448 | METHODDEF(void) |
| 449 | convsamp_float (JSAMPARRAY sample_data, JDIMENSION start_col, FAST_FLOAT * workspace) |
| 450 | { |
| 451 | register FAST_FLOAT *workspaceptr; |
| 452 | register JSAMPROW elemptr; |
| 453 | register int elemr; |
| 454 | |
| 455 | workspaceptr = workspace; |
| 456 | for (elemr = 0; elemr < DCTSIZE; elemr++) { |
| 457 | elemptr = sample_data[elemr] + start_col; |
| 458 | #if DCTSIZE == 8 /* unroll the inner loop */ |
| 459 | *workspaceptr++ = (FAST_FLOAT)(GETJSAMPLE(*elemptr++) - CENTERJSAMPLE); |
| 460 | *workspaceptr++ = (FAST_FLOAT)(GETJSAMPLE(*elemptr++) - CENTERJSAMPLE); |
| 461 | *workspaceptr++ = (FAST_FLOAT)(GETJSAMPLE(*elemptr++) - CENTERJSAMPLE); |
| 462 | *workspaceptr++ = (FAST_FLOAT)(GETJSAMPLE(*elemptr++) - CENTERJSAMPLE); |
| 463 | *workspaceptr++ = (FAST_FLOAT)(GETJSAMPLE(*elemptr++) - CENTERJSAMPLE); |
| 464 | *workspaceptr++ = (FAST_FLOAT)(GETJSAMPLE(*elemptr++) - CENTERJSAMPLE); |
| 465 | *workspaceptr++ = (FAST_FLOAT)(GETJSAMPLE(*elemptr++) - CENTERJSAMPLE); |
| 466 | *workspaceptr++ = (FAST_FLOAT)(GETJSAMPLE(*elemptr++) - CENTERJSAMPLE); |
| 467 | #else |
| 468 | { |
| 469 | register int elemc; |
| 470 | for (elemc = DCTSIZE; elemc > 0; elemc--) |
| 471 | *workspaceptr++ = (FAST_FLOAT) |
| 472 | (GETJSAMPLE(*elemptr++) - CENTERJSAMPLE); |
| 473 | } |
| 474 | #endif |
| 475 | } |
| 476 | } |
| 477 | |
| 478 | |
| 479 | METHODDEF(void) |
| 480 | quantize_float (JCOEFPTR coef_block, FAST_FLOAT * divisors, FAST_FLOAT * workspace) |
| 481 | { |
| 482 | register FAST_FLOAT temp; |
| 483 | register int i; |
| 484 | register JCOEFPTR output_ptr = coef_block; |
| 485 | |
| 486 | for (i = 0; i < DCTSIZE2; i++) { |
| 487 | /* Apply the quantization and scaling factor */ |
| 488 | temp = workspace[i] * divisors[i]; |
| 489 | |
| 490 | /* Round to nearest integer. |
| 491 | * Since C does not specify the direction of rounding for negative |
| 492 | * quotients, we have to force the dividend positive for portability. |
| 493 | * The maximum coefficient size is +-16K (for 12-bit data), so this |
| 494 | * code should work for either 16-bit or 32-bit ints. |
| 495 | */ |
| 496 | output_ptr[i] = (JCOEF) ((int) (temp + (FAST_FLOAT) 16384.5) - 16384); |
| 497 | } |
| 498 | } |
| 499 | |
| 500 | |
Thomas G. Lane | 489583f | 1996-02-07 00:00:00 +0000 | [diff] [blame] | 501 | METHODDEF(void) |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 502 | forward_DCT_float (j_compress_ptr cinfo, jpeg_component_info * compptr, |
| 503 | JSAMPARRAY sample_data, JBLOCKROW coef_blocks, |
| 504 | JDIMENSION start_row, JDIMENSION start_col, |
| 505 | JDIMENSION num_blocks) |
| 506 | /* This version is used for floating-point DCT implementations. */ |
| 507 | { |
| 508 | /* This routine is heavily used, so it's worth coding it tightly. */ |
| 509 | my_fdct_ptr fdct = (my_fdct_ptr) cinfo->fdct; |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 510 | FAST_FLOAT * divisors = fdct->float_divisors[compptr->quant_tbl_no]; |
Pierre Ossman | 35c4719 | 2009-03-09 13:29:37 +0000 | [diff] [blame] | 511 | FAST_FLOAT * workspace; |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 512 | JDIMENSION bi; |
| 513 | |
Pierre Ossman | 35c4719 | 2009-03-09 13:29:37 +0000 | [diff] [blame] | 514 | |
Pierre Ossman | 49dcbfb | 2009-03-09 10:37:20 +0000 | [diff] [blame] | 515 | /* Make sure the compiler doesn't look up these every pass */ |
| 516 | float_DCT_method_ptr do_dct = fdct->float_dct; |
| 517 | float_convsamp_method_ptr do_convsamp = fdct->float_convsamp; |
| 518 | float_quantize_method_ptr do_quantize = fdct->float_quantize; |
Pierre Ossman | dc5db14 | 2009-03-13 12:17:26 +0000 | [diff] [blame] | 519 | workspace = fdct->float_workspace; |
Pierre Ossman | 49dcbfb | 2009-03-09 10:37:20 +0000 | [diff] [blame] | 520 | |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 521 | sample_data += start_row; /* fold in the vertical offset once */ |
| 522 | |
| 523 | for (bi = 0; bi < num_blocks; bi++, start_col += DCTSIZE) { |
| 524 | /* Load data into workspace, applying unsigned->signed conversion */ |
Pierre Ossman | 49dcbfb | 2009-03-09 10:37:20 +0000 | [diff] [blame] | 525 | (*do_convsamp) (sample_data, start_col, workspace); |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 526 | |
| 527 | /* Perform the DCT */ |
| 528 | (*do_dct) (workspace); |
| 529 | |
| 530 | /* Quantize/descale the coefficients, and store into coef_blocks[] */ |
Pierre Ossman | 49dcbfb | 2009-03-09 10:37:20 +0000 | [diff] [blame] | 531 | (*do_quantize) (coef_blocks[bi], divisors, workspace); |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 532 | } |
| 533 | } |
| 534 | |
| 535 | #endif /* DCT_FLOAT_SUPPORTED */ |
| 536 | |
| 537 | |
| 538 | /* |
| 539 | * Initialize FDCT manager. |
| 540 | */ |
| 541 | |
Thomas G. Lane | 489583f | 1996-02-07 00:00:00 +0000 | [diff] [blame] | 542 | GLOBAL(void) |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 543 | jinit_forward_dct (j_compress_ptr cinfo) |
| 544 | { |
| 545 | my_fdct_ptr fdct; |
| 546 | int i; |
| 547 | |
| 548 | fdct = (my_fdct_ptr) |
| 549 | (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, |
| 550 | SIZEOF(my_fdct_controller)); |
| 551 | cinfo->fdct = (struct jpeg_forward_dct *) fdct; |
| 552 | fdct->pub.start_pass = start_pass_fdctmgr; |
| 553 | |
Pierre Ossman | 49dcbfb | 2009-03-09 10:37:20 +0000 | [diff] [blame] | 554 | /* First determine the DCT... */ |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 555 | switch (cinfo->dct_method) { |
| 556 | #ifdef DCT_ISLOW_SUPPORTED |
| 557 | case JDCT_ISLOW: |
| 558 | fdct->pub.forward_DCT = forward_DCT; |
Pierre Ossman | 59a3938 | 2009-03-09 13:15:56 +0000 | [diff] [blame] | 559 | if (jsimd_can_fdct_islow()) |
| 560 | fdct->dct = jsimd_fdct_islow; |
| 561 | else |
| 562 | fdct->dct = jpeg_fdct_islow; |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 563 | break; |
| 564 | #endif |
| 565 | #ifdef DCT_IFAST_SUPPORTED |
| 566 | case JDCT_IFAST: |
| 567 | fdct->pub.forward_DCT = forward_DCT; |
Pierre Ossman | 59a3938 | 2009-03-09 13:15:56 +0000 | [diff] [blame] | 568 | if (jsimd_can_fdct_ifast()) |
| 569 | fdct->dct = jsimd_fdct_ifast; |
| 570 | else |
| 571 | fdct->dct = jpeg_fdct_ifast; |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 572 | break; |
| 573 | #endif |
| 574 | #ifdef DCT_FLOAT_SUPPORTED |
| 575 | case JDCT_FLOAT: |
| 576 | fdct->pub.forward_DCT = forward_DCT_float; |
Pierre Ossman | 59a3938 | 2009-03-09 13:15:56 +0000 | [diff] [blame] | 577 | if (jsimd_can_fdct_float()) |
| 578 | fdct->float_dct = jsimd_fdct_float; |
| 579 | else |
| 580 | fdct->float_dct = jpeg_fdct_float; |
Pierre Ossman | 49dcbfb | 2009-03-09 10:37:20 +0000 | [diff] [blame] | 581 | break; |
| 582 | #endif |
| 583 | default: |
| 584 | ERREXIT(cinfo, JERR_NOT_COMPILED); |
| 585 | break; |
| 586 | } |
| 587 | |
| 588 | /* ...then the supporting stages. */ |
| 589 | switch (cinfo->dct_method) { |
| 590 | #ifdef DCT_ISLOW_SUPPORTED |
| 591 | case JDCT_ISLOW: |
| 592 | #endif |
| 593 | #ifdef DCT_IFAST_SUPPORTED |
| 594 | case JDCT_IFAST: |
| 595 | #endif |
| 596 | #if defined(DCT_ISLOW_SUPPORTED) || defined(DCT_IFAST_SUPPORTED) |
Pierre Ossman | 59a3938 | 2009-03-09 13:15:56 +0000 | [diff] [blame] | 597 | if (jsimd_can_convsamp()) |
| 598 | fdct->convsamp = jsimd_convsamp; |
| 599 | else |
| 600 | fdct->convsamp = convsamp; |
| 601 | if (jsimd_can_quantize()) |
| 602 | fdct->quantize = jsimd_quantize; |
| 603 | else |
| 604 | fdct->quantize = quantize; |
Pierre Ossman | 49dcbfb | 2009-03-09 10:37:20 +0000 | [diff] [blame] | 605 | break; |
| 606 | #endif |
| 607 | #ifdef DCT_FLOAT_SUPPORTED |
| 608 | case JDCT_FLOAT: |
Pierre Ossman | 59a3938 | 2009-03-09 13:15:56 +0000 | [diff] [blame] | 609 | if (jsimd_can_convsamp_float()) |
| 610 | fdct->float_convsamp = jsimd_convsamp_float; |
| 611 | else |
| 612 | fdct->float_convsamp = convsamp_float; |
| 613 | if (jsimd_can_quantize_float()) |
| 614 | fdct->float_quantize = jsimd_quantize_float; |
| 615 | else |
| 616 | fdct->float_quantize = quantize_float; |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 617 | break; |
| 618 | #endif |
| 619 | default: |
| 620 | ERREXIT(cinfo, JERR_NOT_COMPILED); |
| 621 | break; |
| 622 | } |
| 623 | |
Pierre Ossman | 35c4719 | 2009-03-09 13:29:37 +0000 | [diff] [blame] | 624 | /* Allocate workspace memory */ |
| 625 | #ifdef DCT_FLOAT_SUPPORTED |
| 626 | if (cinfo->dct_method == JDCT_FLOAT) |
| 627 | fdct->float_workspace = (FAST_FLOAT *) |
| 628 | (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, |
| 629 | SIZEOF(FAST_FLOAT) * DCTSIZE2); |
| 630 | else |
| 631 | #endif |
| 632 | fdct->workspace = (DCTELEM *) |
| 633 | (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, |
| 634 | SIZEOF(DCTELEM) * DCTSIZE2); |
| 635 | |
Thomas G. Lane | 36a4ccc | 1994-09-24 00:00:00 +0000 | [diff] [blame] | 636 | /* Mark divisor tables unallocated */ |
| 637 | for (i = 0; i < NUM_QUANT_TBLS; i++) { |
| 638 | fdct->divisors[i] = NULL; |
| 639 | #ifdef DCT_FLOAT_SUPPORTED |
| 640 | fdct->float_divisors[i] = NULL; |
| 641 | #endif |
| 642 | } |
| 643 | } |