00001
00002
00003
00004
00005
00006
00007
00008
00009
00010
00011
00012
00013
00014
00015
00016
00017
00018
00019
00020
00021
00022
00023
00024
00025
00026
00027
00028 #define JPEG_INTERNALS
00029 #include "jinclude.h"
00030 #include "jpeglib.h"
00031 #include "jdct.h"
00032
00033 #ifdef DCT_ISLOW_SUPPORTED
00034
00035
00036
00037
00038
00039
00040 #if DCTSIZE != 8
00041 Sorry, this code only copes with 8x8 DCTs.
00042 #endif
00043
00044
00045
00046
00047
00048
00049
00050
00051
00052
00053
00054
00055
00056
00057
00058
00059
00060
00061
00062
00063
00064
00065
00066
00067
00068
00069
00070
00071
00072
00073
00074
00075
00076
00077 #if BITS_IN_JSAMPLE == 8
00078 #define CONST_BITS 13
00079 #define PASS1_BITS 2
00080 #else
00081 #define CONST_BITS 13
00082 #define PASS1_BITS 1
00083 #endif
00084
00085
00086
00087
00088
00089
00090
00091
00092 #if CONST_BITS == 13
00093 #define FIX_0_298631336 ((INT32) 2446)
00094 #define FIX_0_390180644 ((INT32) 3196)
00095 #define FIX_0_541196100 ((INT32) 4433)
00096 #define FIX_0_765366865 ((INT32) 6270)
00097 #define FIX_0_899976223 ((INT32) 7373)
00098 #define FIX_1_175875602 ((INT32) 9633)
00099 #define FIX_1_501321110 ((INT32) 12299)
00100 #define FIX_1_847759065 ((INT32) 15137)
00101 #define FIX_1_961570560 ((INT32) 16069)
00102 #define FIX_2_053119869 ((INT32) 16819)
00103 #define FIX_2_562915447 ((INT32) 20995)
00104 #define FIX_3_072711026 ((INT32) 25172)
00105 #else
00106 #define FIX_0_298631336 FIX(0.298631336)
00107 #define FIX_0_390180644 FIX(0.390180644)
00108 #define FIX_0_541196100 FIX(0.541196100)
00109 #define FIX_0_765366865 FIX(0.765366865)
00110 #define FIX_0_899976223 FIX(0.899976223)
00111 #define FIX_1_175875602 FIX(1.175875602)
00112 #define FIX_1_501321110 FIX(1.501321110)
00113 #define FIX_1_847759065 FIX(1.847759065)
00114 #define FIX_1_961570560 FIX(1.961570560)
00115 #define FIX_2_053119869 FIX(2.053119869)
00116 #define FIX_2_562915447 FIX(2.562915447)
00117 #define FIX_3_072711026 FIX(3.072711026)
00118 #endif
00119
00120
00121
00122
00123
00124
00125
00126
00127
00128 #if BITS_IN_JSAMPLE == 8
00129 #define MULTIPLY(var,const) MULTIPLY16C16(var,const)
00130 #else
00131 #define MULTIPLY(var,const) ((var) * (const))
00132 #endif
00133
00134
00135
00136
00137
00138
00139
00140 #define DEQUANTIZE(coef,quantval) (((ISLOW_MULT_TYPE) (coef)) * (quantval))
00141
00142
00143
00144
00145
00146
00147 GLOBAL(void)
00148 jpeg_idct_islow (j_decompress_ptr cinfo, jpeg_component_info * compptr,
00149 JCOEFPTR coef_block,
00150 JSAMPARRAY output_buf, JDIMENSION output_col)
00151 {
00152 INT32 tmp0, tmp1, tmp2, tmp3;
00153 INT32 tmp10, tmp11, tmp12, tmp13;
00154 INT32 z1, z2, z3, z4, z5;
00155 JCOEFPTR inptr;
00156 ISLOW_MULT_TYPE * quantptr;
00157 int * wsptr;
00158 JSAMPROW outptr;
00159 JSAMPLE *range_limit = IDCT_range_limit(cinfo);
00160 int ctr;
00161 int workspace[DCTSIZE2];
00162 SHIFT_TEMPS
00163
00164
00165
00166
00167
00168 inptr = coef_block;
00169 quantptr = (ISLOW_MULT_TYPE *) compptr->dct_table;
00170 wsptr = workspace;
00171 for (ctr = DCTSIZE; ctr > 0; ctr--) {
00172
00173
00174
00175
00176
00177
00178
00179
00180
00181 if (inptr[DCTSIZE*1] == 0 && inptr[DCTSIZE*2] == 0 &&
00182 inptr[DCTSIZE*3] == 0 && inptr[DCTSIZE*4] == 0 &&
00183 inptr[DCTSIZE*5] == 0 && inptr[DCTSIZE*6] == 0 &&
00184 inptr[DCTSIZE*7] == 0) {
00185
00186 int dcval = DEQUANTIZE(inptr[DCTSIZE*0], quantptr[DCTSIZE*0]) << PASS1_BITS;
00187
00188 wsptr[DCTSIZE*0] = dcval;
00189 wsptr[DCTSIZE*1] = dcval;
00190 wsptr[DCTSIZE*2] = dcval;
00191 wsptr[DCTSIZE*3] = dcval;
00192 wsptr[DCTSIZE*4] = dcval;
00193 wsptr[DCTSIZE*5] = dcval;
00194 wsptr[DCTSIZE*6] = dcval;
00195 wsptr[DCTSIZE*7] = dcval;
00196
00197 inptr++;
00198 quantptr++;
00199 wsptr++;
00200 continue;
00201 }
00202
00203
00204
00205
00206 z2 = DEQUANTIZE(inptr[DCTSIZE*2], quantptr[DCTSIZE*2]);
00207 z3 = DEQUANTIZE(inptr[DCTSIZE*6], quantptr[DCTSIZE*6]);
00208
00209 z1 = MULTIPLY(z2 + z3, FIX_0_541196100);
00210 tmp2 = z1 + MULTIPLY(z3, - FIX_1_847759065);
00211 tmp3 = z1 + MULTIPLY(z2, FIX_0_765366865);
00212
00213 z2 = DEQUANTIZE(inptr[DCTSIZE*0], quantptr[DCTSIZE*0]);
00214 z3 = DEQUANTIZE(inptr[DCTSIZE*4], quantptr[DCTSIZE*4]);
00215
00216 tmp0 = (z2 + z3) << CONST_BITS;
00217 tmp1 = (z2 - z3) << CONST_BITS;
00218
00219 tmp10 = tmp0 + tmp3;
00220 tmp13 = tmp0 - tmp3;
00221 tmp11 = tmp1 + tmp2;
00222 tmp12 = tmp1 - tmp2;
00223
00224
00225
00226
00227
00228 tmp0 = DEQUANTIZE(inptr[DCTSIZE*7], quantptr[DCTSIZE*7]);
00229 tmp1 = DEQUANTIZE(inptr[DCTSIZE*5], quantptr[DCTSIZE*5]);
00230 tmp2 = DEQUANTIZE(inptr[DCTSIZE*3], quantptr[DCTSIZE*3]);
00231 tmp3 = DEQUANTIZE(inptr[DCTSIZE*1], quantptr[DCTSIZE*1]);
00232
00233 z1 = tmp0 + tmp3;
00234 z2 = tmp1 + tmp2;
00235 z3 = tmp0 + tmp2;
00236 z4 = tmp1 + tmp3;
00237 z5 = MULTIPLY(z3 + z4, FIX_1_175875602);
00238
00239 tmp0 = MULTIPLY(tmp0, FIX_0_298631336);
00240 tmp1 = MULTIPLY(tmp1, FIX_2_053119869);
00241 tmp2 = MULTIPLY(tmp2, FIX_3_072711026);
00242 tmp3 = MULTIPLY(tmp3, FIX_1_501321110);
00243 z1 = MULTIPLY(z1, - FIX_0_899976223);
00244 z2 = MULTIPLY(z2, - FIX_2_562915447);
00245 z3 = MULTIPLY(z3, - FIX_1_961570560);
00246 z4 = MULTIPLY(z4, - FIX_0_390180644);
00247
00248 z3 += z5;
00249 z4 += z5;
00250
00251 tmp0 += z1 + z3;
00252 tmp1 += z2 + z4;
00253 tmp2 += z2 + z3;
00254 tmp3 += z1 + z4;
00255
00256
00257
00258 wsptr[DCTSIZE*0] = (int) DESCALE(tmp10 + tmp3, CONST_BITS-PASS1_BITS);
00259 wsptr[DCTSIZE*7] = (int) DESCALE(tmp10 - tmp3, CONST_BITS-PASS1_BITS);
00260 wsptr[DCTSIZE*1] = (int) DESCALE(tmp11 + tmp2, CONST_BITS-PASS1_BITS);
00261 wsptr[DCTSIZE*6] = (int) DESCALE(tmp11 - tmp2, CONST_BITS-PASS1_BITS);
00262 wsptr[DCTSIZE*2] = (int) DESCALE(tmp12 + tmp1, CONST_BITS-PASS1_BITS);
00263 wsptr[DCTSIZE*5] = (int) DESCALE(tmp12 - tmp1, CONST_BITS-PASS1_BITS);
00264 wsptr[DCTSIZE*3] = (int) DESCALE(tmp13 + tmp0, CONST_BITS-PASS1_BITS);
00265 wsptr[DCTSIZE*4] = (int) DESCALE(tmp13 - tmp0, CONST_BITS-PASS1_BITS);
00266
00267 inptr++;
00268 quantptr++;
00269 wsptr++;
00270 }
00271
00272
00273
00274
00275
00276 wsptr = workspace;
00277 for (ctr = 0; ctr < DCTSIZE; ctr++) {
00278 outptr = output_buf[ctr] + output_col;
00279
00280
00281
00282
00283
00284
00285
00286
00287 #ifndef NO_ZERO_ROW_TEST
00288 if (wsptr[1] == 0 && wsptr[2] == 0 && wsptr[3] == 0 && wsptr[4] == 0 &&
00289 wsptr[5] == 0 && wsptr[6] == 0 && wsptr[7] == 0) {
00290
00291 JSAMPLE dcval = range_limit[(int) DESCALE((INT32) wsptr[0], PASS1_BITS+3)
00292 & RANGE_MASK];
00293
00294 outptr[0] = dcval;
00295 outptr[1] = dcval;
00296 outptr[2] = dcval;
00297 outptr[3] = dcval;
00298 outptr[4] = dcval;
00299 outptr[5] = dcval;
00300 outptr[6] = dcval;
00301 outptr[7] = dcval;
00302
00303 wsptr += DCTSIZE;
00304 continue;
00305 }
00306 #endif
00307
00308
00309
00310
00311 z2 = (INT32) wsptr[2];
00312 z3 = (INT32) wsptr[6];
00313
00314 z1 = MULTIPLY(z2 + z3, FIX_0_541196100);
00315 tmp2 = z1 + MULTIPLY(z3, - FIX_1_847759065);
00316 tmp3 = z1 + MULTIPLY(z2, FIX_0_765366865);
00317
00318 tmp0 = ((INT32) wsptr[0] + (INT32) wsptr[4]) << CONST_BITS;
00319 tmp1 = ((INT32) wsptr[0] - (INT32) wsptr[4]) << CONST_BITS;
00320
00321 tmp10 = tmp0 + tmp3;
00322 tmp13 = tmp0 - tmp3;
00323 tmp11 = tmp1 + tmp2;
00324 tmp12 = tmp1 - tmp2;
00325
00326
00327
00328
00329
00330 tmp0 = (INT32) wsptr[7];
00331 tmp1 = (INT32) wsptr[5];
00332 tmp2 = (INT32) wsptr[3];
00333 tmp3 = (INT32) wsptr[1];
00334
00335 z1 = tmp0 + tmp3;
00336 z2 = tmp1 + tmp2;
00337 z3 = tmp0 + tmp2;
00338 z4 = tmp1 + tmp3;
00339 z5 = MULTIPLY(z3 + z4, FIX_1_175875602);
00340
00341 tmp0 = MULTIPLY(tmp0, FIX_0_298631336);
00342 tmp1 = MULTIPLY(tmp1, FIX_2_053119869);
00343 tmp2 = MULTIPLY(tmp2, FIX_3_072711026);
00344 tmp3 = MULTIPLY(tmp3, FIX_1_501321110);
00345 z1 = MULTIPLY(z1, - FIX_0_899976223);
00346 z2 = MULTIPLY(z2, - FIX_2_562915447);
00347 z3 = MULTIPLY(z3, - FIX_1_961570560);
00348 z4 = MULTIPLY(z4, - FIX_0_390180644);
00349
00350 z3 += z5;
00351 z4 += z5;
00352
00353 tmp0 += z1 + z3;
00354 tmp1 += z2 + z4;
00355 tmp2 += z2 + z3;
00356 tmp3 += z1 + z4;
00357
00358
00359
00360 outptr[0] = range_limit[(int) DESCALE(tmp10 + tmp3,
00361 CONST_BITS+PASS1_BITS+3)
00362 & RANGE_MASK];
00363 outptr[7] = range_limit[(int) DESCALE(tmp10 - tmp3,
00364 CONST_BITS+PASS1_BITS+3)
00365 & RANGE_MASK];
00366 outptr[1] = range_limit[(int) DESCALE(tmp11 + tmp2,
00367 CONST_BITS+PASS1_BITS+3)
00368 & RANGE_MASK];
00369 outptr[6] = range_limit[(int) DESCALE(tmp11 - tmp2,
00370 CONST_BITS+PASS1_BITS+3)
00371 & RANGE_MASK];
00372 outptr[2] = range_limit[(int) DESCALE(tmp12 + tmp1,
00373 CONST_BITS+PASS1_BITS+3)
00374 & RANGE_MASK];
00375 outptr[5] = range_limit[(int) DESCALE(tmp12 - tmp1,
00376 CONST_BITS+PASS1_BITS+3)
00377 & RANGE_MASK];
00378 outptr[3] = range_limit[(int) DESCALE(tmp13 + tmp0,
00379 CONST_BITS+PASS1_BITS+3)
00380 & RANGE_MASK];
00381 outptr[4] = range_limit[(int) DESCALE(tmp13 - tmp0,
00382 CONST_BITS+PASS1_BITS+3)
00383 & RANGE_MASK];
00384
00385 wsptr += DCTSIZE;
00386 }
00387 }
00388
00389 #endif