Doxygen Source Code Documentation
jidctred.c File Reference
#include "jinclude.h"
#include "jpeglib.h"
#include "jdct.h"
Go to the source code of this file.
Define Documentation
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Definition at line 43 of file jidctred.c. Referenced by jpeg_idct_2x2(), and jpeg_idct_4x4(). |
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Definition at line 109 of file jidctred.c. |
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Definition at line 58 of file jidctred.c. Referenced by jpeg_idct_4x4(). |
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Definition at line 59 of file jidctred.c. Referenced by jpeg_idct_4x4(). |
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Definition at line 60 of file jidctred.c. Referenced by jpeg_idct_4x4(). |
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Definition at line 61 of file jidctred.c. Referenced by jpeg_idct_2x2(). |
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Definition at line 62 of file jidctred.c. Referenced by jpeg_idct_4x4(). |
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Definition at line 63 of file jidctred.c. Referenced by jpeg_idct_2x2(). |
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Definition at line 64 of file jidctred.c. Referenced by jpeg_idct_4x4(). |
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Definition at line 65 of file jidctred.c. Referenced by jpeg_idct_4x4(). |
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Definition at line 66 of file jidctred.c. Referenced by jpeg_idct_2x2(). |
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Definition at line 67 of file jidctred.c. Referenced by jpeg_idct_4x4(). |
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Definition at line 68 of file jidctred.c. Referenced by jpeg_idct_4x4(). |
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Definition at line 69 of file jidctred.c. Referenced by jpeg_idct_4x4(). |
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Definition at line 70 of file jidctred.c. Referenced by jpeg_idct_4x4(). |
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Definition at line 71 of file jidctred.c. Referenced by jpeg_idct_2x2(). |
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Definition at line 23 of file jidctred.c. |
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Definition at line 98 of file jidctred.c. |
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Definition at line 44 of file jidctred.c. Referenced by jpeg_idct_2x2(), and jpeg_idct_4x4(). |
Function Documentation
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Definition at line 379 of file jidctred.c. References coef_block, compptr, jpeg_component_info::dct_table, DEQUANTIZE, DESCALE, IDCT_range_limit, INT32, ISLOW_MULT_TYPE, JCOEFPTR, JDIMENSION, JSAMPARRAY, JSAMPLE, output_col, and RANGE_MASK. Referenced by start_pass().
00382 { 00383 int dcval; 00384 ISLOW_MULT_TYPE * quantptr; 00385 JSAMPLE *range_limit = IDCT_range_limit(cinfo); 00386 SHIFT_TEMPS 00387 00388 /* We hardly need an inverse DCT routine for this: just take the 00389 * average pixel value, which is one-eighth of the DC coefficient. 00390 */ 00391 quantptr = (ISLOW_MULT_TYPE *) compptr->dct_table; 00392 dcval = DEQUANTIZE(coef_block[0], quantptr[0]); 00393 dcval = (int) DESCALE((INT32) dcval, 3); 00394 00395 output_buf[0][output_col] = range_limit[dcval & RANGE_MASK]; 00396 } |
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Definition at line 271 of file jidctred.c. References coef_block, compptr, CONST_BITS, jpeg_component_info::dct_table, DEQUANTIZE, DESCALE, FIX_0_720959822, FIX_0_850430095, FIX_1_272758580, FIX_3_624509785, IDCT_range_limit, INT32, ISLOW_MULT_TYPE, JCOEFPTR, JDIMENSION, JSAMPARRAY, JSAMPLE, JSAMPROW, MULTIPLY, output_col, PASS1_BITS, RANGE_MASK, and z1. Referenced by start_pass().
00274 { 00275 INT32 tmp0, tmp10, z1; 00276 JCOEFPTR inptr; 00277 ISLOW_MULT_TYPE * quantptr; 00278 int * wsptr; 00279 JSAMPROW outptr; 00280 JSAMPLE *range_limit = IDCT_range_limit(cinfo); 00281 int ctr; 00282 int workspace[DCTSIZE*2]; /* buffers data between passes */ 00283 SHIFT_TEMPS 00284 00285 /* Pass 1: process columns from input, store into work array. */ 00286 00287 inptr = coef_block; 00288 quantptr = (ISLOW_MULT_TYPE *) compptr->dct_table; 00289 wsptr = workspace; 00290 for (ctr = DCTSIZE; ctr > 0; inptr++, quantptr++, wsptr++, ctr--) { 00291 /* Don't bother to process columns 2,4,6 */ 00292 if (ctr == DCTSIZE-2 || ctr == DCTSIZE-4 || ctr == DCTSIZE-6) 00293 continue; 00294 if (inptr[DCTSIZE*1] == 0 && inptr[DCTSIZE*3] == 0 && 00295 inptr[DCTSIZE*5] == 0 && inptr[DCTSIZE*7] == 0) { 00296 /* AC terms all zero; we need not examine terms 2,4,6 for 2x2 output */ 00297 int dcval = DEQUANTIZE(inptr[DCTSIZE*0], quantptr[DCTSIZE*0]) << PASS1_BITS; 00298 00299 wsptr[DCTSIZE*0] = dcval; 00300 wsptr[DCTSIZE*1] = dcval; 00301 00302 continue; 00303 } 00304 00305 /* Even part */ 00306 00307 z1 = DEQUANTIZE(inptr[DCTSIZE*0], quantptr[DCTSIZE*0]); 00308 tmp10 = z1 << (CONST_BITS+2); 00309 00310 /* Odd part */ 00311 00312 z1 = DEQUANTIZE(inptr[DCTSIZE*7], quantptr[DCTSIZE*7]); 00313 tmp0 = MULTIPLY(z1, - FIX_0_720959822); /* sqrt(2) * (c7-c5+c3-c1) */ 00314 z1 = DEQUANTIZE(inptr[DCTSIZE*5], quantptr[DCTSIZE*5]); 00315 tmp0 += MULTIPLY(z1, FIX_0_850430095); /* sqrt(2) * (-c1+c3+c5+c7) */ 00316 z1 = DEQUANTIZE(inptr[DCTSIZE*3], quantptr[DCTSIZE*3]); 00317 tmp0 += MULTIPLY(z1, - FIX_1_272758580); /* sqrt(2) * (-c1+c3-c5-c7) */ 00318 z1 = DEQUANTIZE(inptr[DCTSIZE*1], quantptr[DCTSIZE*1]); 00319 tmp0 += MULTIPLY(z1, FIX_3_624509785); /* sqrt(2) * (c1+c3+c5+c7) */ 00320 00321 /* Final output stage */ 00322 00323 wsptr[DCTSIZE*0] = (int) DESCALE(tmp10 + tmp0, CONST_BITS-PASS1_BITS+2); 00324 wsptr[DCTSIZE*1] = (int) DESCALE(tmp10 - tmp0, CONST_BITS-PASS1_BITS+2); 00325 } 00326 00327 /* Pass 2: process 2 rows from work array, store into output array. */ 00328 00329 wsptr = workspace; 00330 for (ctr = 0; ctr < 2; ctr++) { 00331 outptr = output_buf[ctr] + output_col; 00332 /* It's not clear whether a zero row test is worthwhile here ... */ 00333 00334 #ifndef NO_ZERO_ROW_TEST 00335 if (wsptr[1] == 0 && wsptr[3] == 0 && wsptr[5] == 0 && wsptr[7] == 0) { 00336 /* AC terms all zero */ 00337 JSAMPLE dcval = range_limit[(int) DESCALE((INT32) wsptr[0], PASS1_BITS+3) 00338 & RANGE_MASK]; 00339 00340 outptr[0] = dcval; 00341 outptr[1] = dcval; 00342 00343 wsptr += DCTSIZE; /* advance pointer to next row */ 00344 continue; 00345 } 00346 #endif 00347 00348 /* Even part */ 00349 00350 tmp10 = ((INT32) wsptr[0]) << (CONST_BITS+2); 00351 00352 /* Odd part */ 00353 00354 tmp0 = MULTIPLY((INT32) wsptr[7], - FIX_0_720959822) /* sqrt(2) * (c7-c5+c3-c1) */ 00355 + MULTIPLY((INT32) wsptr[5], FIX_0_850430095) /* sqrt(2) * (-c1+c3+c5+c7) */ 00356 + MULTIPLY((INT32) wsptr[3], - FIX_1_272758580) /* sqrt(2) * (-c1+c3-c5-c7) */ 00357 + MULTIPLY((INT32) wsptr[1], FIX_3_624509785); /* sqrt(2) * (c1+c3+c5+c7) */ 00358 00359 /* Final output stage */ 00360 00361 outptr[0] = range_limit[(int) DESCALE(tmp10 + tmp0, 00362 CONST_BITS+PASS1_BITS+3+2) 00363 & RANGE_MASK]; 00364 outptr[1] = range_limit[(int) DESCALE(tmp10 - tmp0, 00365 CONST_BITS+PASS1_BITS+3+2) 00366 & RANGE_MASK]; 00367 00368 wsptr += DCTSIZE; /* advance pointer to next row */ 00369 } 00370 } |
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Definition at line 118 of file jidctred.c. References coef_block, compptr, CONST_BITS, jpeg_component_info::dct_table, DEQUANTIZE, DESCALE, FIX_0_211164243, FIX_0_509795579, FIX_0_601344887, FIX_0_765366865, FIX_0_899976223, FIX_1_061594337, FIX_1_451774981, FIX_1_847759065, FIX_2_172734803, FIX_2_562915447, IDCT_range_limit, INT32, ISLOW_MULT_TYPE, JCOEFPTR, JDIMENSION, JSAMPARRAY, JSAMPLE, JSAMPROW, MULTIPLY, output_col, PASS1_BITS, RANGE_MASK, and z1. Referenced by start_pass().
00121 { 00122 INT32 tmp0, tmp2, tmp10, tmp12; 00123 INT32 z1, z2, z3, z4; 00124 JCOEFPTR inptr; 00125 ISLOW_MULT_TYPE * quantptr; 00126 int * wsptr; 00127 JSAMPROW outptr; 00128 JSAMPLE *range_limit = IDCT_range_limit(cinfo); 00129 int ctr; 00130 int workspace[DCTSIZE*4]; /* buffers data between passes */ 00131 SHIFT_TEMPS 00132 00133 /* Pass 1: process columns from input, store into work array. */ 00134 00135 inptr = coef_block; 00136 quantptr = (ISLOW_MULT_TYPE *) compptr->dct_table; 00137 wsptr = workspace; 00138 for (ctr = DCTSIZE; ctr > 0; inptr++, quantptr++, wsptr++, ctr--) { 00139 /* Don't bother to process column 4, because second pass won't use it */ 00140 if (ctr == DCTSIZE-4) 00141 continue; 00142 if (inptr[DCTSIZE*1] == 0 && inptr[DCTSIZE*2] == 0 && 00143 inptr[DCTSIZE*3] == 0 && inptr[DCTSIZE*5] == 0 && 00144 inptr[DCTSIZE*6] == 0 && inptr[DCTSIZE*7] == 0) { 00145 /* AC terms all zero; we need not examine term 4 for 4x4 output */ 00146 int dcval = DEQUANTIZE(inptr[DCTSIZE*0], quantptr[DCTSIZE*0]) << PASS1_BITS; 00147 00148 wsptr[DCTSIZE*0] = dcval; 00149 wsptr[DCTSIZE*1] = dcval; 00150 wsptr[DCTSIZE*2] = dcval; 00151 wsptr[DCTSIZE*3] = dcval; 00152 00153 continue; 00154 } 00155 00156 /* Even part */ 00157 00158 tmp0 = DEQUANTIZE(inptr[DCTSIZE*0], quantptr[DCTSIZE*0]); 00159 tmp0 <<= (CONST_BITS+1); 00160 00161 z2 = DEQUANTIZE(inptr[DCTSIZE*2], quantptr[DCTSIZE*2]); 00162 z3 = DEQUANTIZE(inptr[DCTSIZE*6], quantptr[DCTSIZE*6]); 00163 00164 tmp2 = MULTIPLY(z2, FIX_1_847759065) + MULTIPLY(z3, - FIX_0_765366865); 00165 00166 tmp10 = tmp0 + tmp2; 00167 tmp12 = tmp0 - tmp2; 00168 00169 /* Odd part */ 00170 00171 z1 = DEQUANTIZE(inptr[DCTSIZE*7], quantptr[DCTSIZE*7]); 00172 z2 = DEQUANTIZE(inptr[DCTSIZE*5], quantptr[DCTSIZE*5]); 00173 z3 = DEQUANTIZE(inptr[DCTSIZE*3], quantptr[DCTSIZE*3]); 00174 z4 = DEQUANTIZE(inptr[DCTSIZE*1], quantptr[DCTSIZE*1]); 00175 00176 tmp0 = MULTIPLY(z1, - FIX_0_211164243) /* sqrt(2) * (c3-c1) */ 00177 + MULTIPLY(z2, FIX_1_451774981) /* sqrt(2) * (c3+c7) */ 00178 + MULTIPLY(z3, - FIX_2_172734803) /* sqrt(2) * (-c1-c5) */ 00179 + MULTIPLY(z4, FIX_1_061594337); /* sqrt(2) * (c5+c7) */ 00180 00181 tmp2 = MULTIPLY(z1, - FIX_0_509795579) /* sqrt(2) * (c7-c5) */ 00182 + MULTIPLY(z2, - FIX_0_601344887) /* sqrt(2) * (c5-c1) */ 00183 + MULTIPLY(z3, FIX_0_899976223) /* sqrt(2) * (c3-c7) */ 00184 + MULTIPLY(z4, FIX_2_562915447); /* sqrt(2) * (c1+c3) */ 00185 00186 /* Final output stage */ 00187 00188 wsptr[DCTSIZE*0] = (int) DESCALE(tmp10 + tmp2, CONST_BITS-PASS1_BITS+1); 00189 wsptr[DCTSIZE*3] = (int) DESCALE(tmp10 - tmp2, CONST_BITS-PASS1_BITS+1); 00190 wsptr[DCTSIZE*1] = (int) DESCALE(tmp12 + tmp0, CONST_BITS-PASS1_BITS+1); 00191 wsptr[DCTSIZE*2] = (int) DESCALE(tmp12 - tmp0, CONST_BITS-PASS1_BITS+1); 00192 } 00193 00194 /* Pass 2: process 4 rows from work array, store into output array. */ 00195 00196 wsptr = workspace; 00197 for (ctr = 0; ctr < 4; ctr++) { 00198 outptr = output_buf[ctr] + output_col; 00199 /* It's not clear whether a zero row test is worthwhile here ... */ 00200 00201 #ifndef NO_ZERO_ROW_TEST 00202 if (wsptr[1] == 0 && wsptr[2] == 0 && wsptr[3] == 0 && 00203 wsptr[5] == 0 && wsptr[6] == 0 && wsptr[7] == 0) { 00204 /* AC terms all zero */ 00205 JSAMPLE dcval = range_limit[(int) DESCALE((INT32) wsptr[0], PASS1_BITS+3) 00206 & RANGE_MASK]; 00207 00208 outptr[0] = dcval; 00209 outptr[1] = dcval; 00210 outptr[2] = dcval; 00211 outptr[3] = dcval; 00212 00213 wsptr += DCTSIZE; /* advance pointer to next row */ 00214 continue; 00215 } 00216 #endif 00217 00218 /* Even part */ 00219 00220 tmp0 = ((INT32) wsptr[0]) << (CONST_BITS+1); 00221 00222 tmp2 = MULTIPLY((INT32) wsptr[2], FIX_1_847759065) 00223 + MULTIPLY((INT32) wsptr[6], - FIX_0_765366865); 00224 00225 tmp10 = tmp0 + tmp2; 00226 tmp12 = tmp0 - tmp2; 00227 00228 /* Odd part */ 00229 00230 z1 = (INT32) wsptr[7]; 00231 z2 = (INT32) wsptr[5]; 00232 z3 = (INT32) wsptr[3]; 00233 z4 = (INT32) wsptr[1]; 00234 00235 tmp0 = MULTIPLY(z1, - FIX_0_211164243) /* sqrt(2) * (c3-c1) */ 00236 + MULTIPLY(z2, FIX_1_451774981) /* sqrt(2) * (c3+c7) */ 00237 + MULTIPLY(z3, - FIX_2_172734803) /* sqrt(2) * (-c1-c5) */ 00238 + MULTIPLY(z4, FIX_1_061594337); /* sqrt(2) * (c5+c7) */ 00239 00240 tmp2 = MULTIPLY(z1, - FIX_0_509795579) /* sqrt(2) * (c7-c5) */ 00241 + MULTIPLY(z2, - FIX_0_601344887) /* sqrt(2) * (c5-c1) */ 00242 + MULTIPLY(z3, FIX_0_899976223) /* sqrt(2) * (c3-c7) */ 00243 + MULTIPLY(z4, FIX_2_562915447); /* sqrt(2) * (c1+c3) */ 00244 00245 /* Final output stage */ 00246 00247 outptr[0] = range_limit[(int) DESCALE(tmp10 + tmp2, 00248 CONST_BITS+PASS1_BITS+3+1) 00249 & RANGE_MASK]; 00250 outptr[3] = range_limit[(int) DESCALE(tmp10 - tmp2, 00251 CONST_BITS+PASS1_BITS+3+1) 00252 & RANGE_MASK]; 00253 outptr[1] = range_limit[(int) DESCALE(tmp12 + tmp0, 00254 CONST_BITS+PASS1_BITS+3+1) 00255 & RANGE_MASK]; 00256 outptr[2] = range_limit[(int) DESCALE(tmp12 - tmp0, 00257 CONST_BITS+PASS1_BITS+3+1) 00258 & RANGE_MASK]; 00259 00260 wsptr += DCTSIZE; /* advance pointer to next row */ 00261 } 00262 } |