| OLD | NEW |
| 1 /* | 1 /* |
| 2 * jidctred.c | 2 * jidctred.c |
| 3 * | 3 * |
| 4 * This file was part of the Independent JPEG Group's software. |
| 4 * Copyright (C) 1994-1998, Thomas G. Lane. | 5 * Copyright (C) 1994-1998, Thomas G. Lane. |
| 5 * This file is part of the Independent JPEG Group's software. | 6 * libjpeg-turbo Modifications: |
| 6 * For conditions of distribution and use, see the accompanying README file. | 7 * Copyright (C) 2015, D. R. Commander |
| 8 * For conditions of distribution and use, see the accompanying README.ijg |
| 9 * file. |
| 7 * | 10 * |
| 8 * This file contains inverse-DCT routines that produce reduced-size output: | 11 * This file contains inverse-DCT routines that produce reduced-size output: |
| 9 * either 4x4, 2x2, or 1x1 pixels from an 8x8 DCT block. | 12 * either 4x4, 2x2, or 1x1 pixels from an 8x8 DCT block. |
| 10 * | 13 * |
| 11 * The implementation is based on the Loeffler, Ligtenberg and Moschytz (LL&M) | 14 * The implementation is based on the Loeffler, Ligtenberg and Moschytz (LL&M) |
| 12 * algorithm used in jidctint.c. We simply replace each 8-to-8 1-D IDCT step | 15 * algorithm used in jidctint.c. We simply replace each 8-to-8 1-D IDCT step |
| 13 * with an 8-to-4 step that produces the four averages of two adjacent outputs | 16 * with an 8-to-4 step that produces the four averages of two adjacent outputs |
| 14 * (or an 8-to-2 step producing two averages of four outputs, for 2x2 output). | 17 * (or an 8-to-2 step producing two averages of four outputs, for 2x2 output). |
| 15 * These steps were derived by computing the corresponding values at the end | 18 * These steps were derived by computing the corresponding values at the end |
| 16 * of the normal LL&M code, then simplifying as much as possible. | 19 * of the normal LL&M code, then simplifying as much as possible. |
| 17 * | 20 * |
| 18 * 1x1 is trivial: just take the DC coefficient divided by 8. | 21 * 1x1 is trivial: just take the DC coefficient divided by 8. |
| 19 * | 22 * |
| 20 * See jidctint.c for additional comments. | 23 * See jidctint.c for additional comments. |
| 21 */ | 24 */ |
| 22 | 25 |
| 23 #define JPEG_INTERNALS | 26 #define JPEG_INTERNALS |
| 24 #include "jinclude.h" | 27 #include "jinclude.h" |
| 25 #include "jpeglib.h" | 28 #include "jpeglib.h" |
| 26 #include "jdct.h"» » /* Private declarations for DCT subsystem */ | 29 #include "jdct.h" /* Private declarations for DCT subsystem */ |
| 27 | 30 |
| 28 #ifdef IDCT_SCALING_SUPPORTED | 31 #ifdef IDCT_SCALING_SUPPORTED |
| 29 | 32 |
| 30 | 33 |
| 31 /* | 34 /* |
| 32 * This module is specialized to the case DCTSIZE = 8. | 35 * This module is specialized to the case DCTSIZE = 8. |
| 33 */ | 36 */ |
| 34 | 37 |
| 35 #if DCTSIZE != 8 | 38 #if DCTSIZE != 8 |
| 36 Sorry, this code only copes with 8x8 DCTs. /* deliberate syntax err */ | 39 Sorry, this code only copes with 8x8 DCTs. /* deliberate syntax err */ |
| 37 #endif | 40 #endif |
| 38 | 41 |
| 39 | 42 |
| 40 /* Scaling is the same as in jidctint.c. */ | 43 /* Scaling is the same as in jidctint.c. */ |
| 41 | 44 |
| 42 #if BITS_IN_JSAMPLE == 8 | 45 #if BITS_IN_JSAMPLE == 8 |
| 43 #define CONST_BITS 13 | 46 #define CONST_BITS 13 |
| 44 #define PASS1_BITS 2 | 47 #define PASS1_BITS 2 |
| 45 #else | 48 #else |
| 46 #define CONST_BITS 13 | 49 #define CONST_BITS 13 |
| 47 #define PASS1_BITS 1» » /* lose a little precision to avoid overflow */ | 50 #define PASS1_BITS 1 /* lose a little precision to avoid overflow */ |
| 48 #endif | 51 #endif |
| 49 | 52 |
| 50 /* Some C compilers fail to reduce "FIX(constant)" at compile time, thus | 53 /* Some C compilers fail to reduce "FIX(constant)" at compile time, thus |
| 51 * causing a lot of useless floating-point operations at run time. | 54 * causing a lot of useless floating-point operations at run time. |
| 52 * To get around this we use the following pre-calculated constants. | 55 * To get around this we use the following pre-calculated constants. |
| 53 * If you change CONST_BITS you may want to add appropriate values. | 56 * If you change CONST_BITS you may want to add appropriate values. |
| 54 * (With a reasonable C compiler, you can just rely on the FIX() macro...) | 57 * (With a reasonable C compiler, you can just rely on the FIX() macro...) |
| 55 */ | 58 */ |
| 56 | 59 |
| 57 #if CONST_BITS == 13 | 60 #if CONST_BITS == 13 |
| 58 #define FIX_0_211164243 ((INT32) 1730)» /* FIX(0.211164243) */ | 61 #define FIX_0_211164243 ((JLONG) 1730) /* FIX(0.211164243) */ |
| 59 #define FIX_0_509795579 ((INT32) 4176)» /* FIX(0.509795579) */ | 62 #define FIX_0_509795579 ((JLONG) 4176) /* FIX(0.509795579) */ |
| 60 #define FIX_0_601344887 ((INT32) 4926)» /* FIX(0.601344887) */ | 63 #define FIX_0_601344887 ((JLONG) 4926) /* FIX(0.601344887) */ |
| 61 #define FIX_0_720959822 ((INT32) 5906)» /* FIX(0.720959822) */ | 64 #define FIX_0_720959822 ((JLONG) 5906) /* FIX(0.720959822) */ |
| 62 #define FIX_0_765366865 ((INT32) 6270)» /* FIX(0.765366865) */ | 65 #define FIX_0_765366865 ((JLONG) 6270) /* FIX(0.765366865) */ |
| 63 #define FIX_0_850430095 ((INT32) 6967)» /* FIX(0.850430095) */ | 66 #define FIX_0_850430095 ((JLONG) 6967) /* FIX(0.850430095) */ |
| 64 #define FIX_0_899976223 ((INT32) 7373)» /* FIX(0.899976223) */ | 67 #define FIX_0_899976223 ((JLONG) 7373) /* FIX(0.899976223) */ |
| 65 #define FIX_1_061594337 ((INT32) 8697)» /* FIX(1.061594337) */ | 68 #define FIX_1_061594337 ((JLONG) 8697) /* FIX(1.061594337) */ |
| 66 #define FIX_1_272758580 ((INT32) 10426)» /* FIX(1.272758580) */ | 69 #define FIX_1_272758580 ((JLONG) 10426) /* FIX(1.272758580) */ |
| 67 #define FIX_1_451774981 ((INT32) 11893)» /* FIX(1.451774981) */ | 70 #define FIX_1_451774981 ((JLONG) 11893) /* FIX(1.451774981) */ |
| 68 #define FIX_1_847759065 ((INT32) 15137)» /* FIX(1.847759065) */ | 71 #define FIX_1_847759065 ((JLONG) 15137) /* FIX(1.847759065) */ |
| 69 #define FIX_2_172734803 ((INT32) 17799)» /* FIX(2.172734803) */ | 72 #define FIX_2_172734803 ((JLONG) 17799) /* FIX(2.172734803) */ |
| 70 #define FIX_2_562915447 ((INT32) 20995)» /* FIX(2.562915447) */ | 73 #define FIX_2_562915447 ((JLONG) 20995) /* FIX(2.562915447) */ |
| 71 #define FIX_3_624509785 ((INT32) 29692)» /* FIX(3.624509785) */ | 74 #define FIX_3_624509785 ((JLONG) 29692) /* FIX(3.624509785) */ |
| 72 #else | 75 #else |
| 73 #define FIX_0_211164243 FIX(0.211164243) | 76 #define FIX_0_211164243 FIX(0.211164243) |
| 74 #define FIX_0_509795579 FIX(0.509795579) | 77 #define FIX_0_509795579 FIX(0.509795579) |
| 75 #define FIX_0_601344887 FIX(0.601344887) | 78 #define FIX_0_601344887 FIX(0.601344887) |
| 76 #define FIX_0_720959822 FIX(0.720959822) | 79 #define FIX_0_720959822 FIX(0.720959822) |
| 77 #define FIX_0_765366865 FIX(0.765366865) | 80 #define FIX_0_765366865 FIX(0.765366865) |
| 78 #define FIX_0_850430095 FIX(0.850430095) | 81 #define FIX_0_850430095 FIX(0.850430095) |
| 79 #define FIX_0_899976223 FIX(0.899976223) | 82 #define FIX_0_899976223 FIX(0.899976223) |
| 80 #define FIX_1_061594337 FIX(1.061594337) | 83 #define FIX_1_061594337 FIX(1.061594337) |
| 81 #define FIX_1_272758580 FIX(1.272758580) | 84 #define FIX_1_272758580 FIX(1.272758580) |
| 82 #define FIX_1_451774981 FIX(1.451774981) | 85 #define FIX_1_451774981 FIX(1.451774981) |
| 83 #define FIX_1_847759065 FIX(1.847759065) | 86 #define FIX_1_847759065 FIX(1.847759065) |
| 84 #define FIX_2_172734803 FIX(2.172734803) | 87 #define FIX_2_172734803 FIX(2.172734803) |
| 85 #define FIX_2_562915447 FIX(2.562915447) | 88 #define FIX_2_562915447 FIX(2.562915447) |
| 86 #define FIX_3_624509785 FIX(3.624509785) | 89 #define FIX_3_624509785 FIX(3.624509785) |
| 87 #endif | 90 #endif |
| 88 | 91 |
| 89 | 92 |
| 90 /* Multiply an INT32 variable by an INT32 constant to yield an INT32 result. | 93 /* Multiply a JLONG variable by a JLONG constant to yield a JLONG result. |
| 91 * For 8-bit samples with the recommended scaling, all the variable | 94 * For 8-bit samples with the recommended scaling, all the variable |
| 92 * and constant values involved are no more than 16 bits wide, so a | 95 * and constant values involved are no more than 16 bits wide, so a |
| 93 * 16x16->32 bit multiply can be used instead of a full 32x32 multiply. | 96 * 16x16->32 bit multiply can be used instead of a full 32x32 multiply. |
| 94 * For 12-bit samples, a full 32-bit multiplication will be needed. | 97 * For 12-bit samples, a full 32-bit multiplication will be needed. |
| 95 */ | 98 */ |
| 96 | 99 |
| 97 #if BITS_IN_JSAMPLE == 8 | 100 #if BITS_IN_JSAMPLE == 8 |
| 98 #define MULTIPLY(var,const) MULTIPLY16C16(var,const) | 101 #define MULTIPLY(var,const) MULTIPLY16C16(var,const) |
| 99 #else | 102 #else |
| 100 #define MULTIPLY(var,const) ((var) * (const)) | 103 #define MULTIPLY(var,const) ((var) * (const)) |
| 101 #endif | 104 #endif |
| 102 | 105 |
| 103 | 106 |
| 104 /* Dequantize a coefficient by multiplying it by the multiplier-table | 107 /* Dequantize a coefficient by multiplying it by the multiplier-table |
| 105 * entry; produce an int result. In this module, both inputs and result | 108 * entry; produce an int result. In this module, both inputs and result |
| 106 * are 16 bits or less, so either int or short multiply will work. | 109 * are 16 bits or less, so either int or short multiply will work. |
| 107 */ | 110 */ |
| 108 | 111 |
| 109 #define DEQUANTIZE(coef,quantval) (((ISLOW_MULT_TYPE) (coef)) * (quantval)) | 112 #define DEQUANTIZE(coef,quantval) (((ISLOW_MULT_TYPE) (coef)) * (quantval)) |
| 110 | 113 |
| 111 | 114 |
| 112 /* | 115 /* |
| 113 * Perform dequantization and inverse DCT on one block of coefficients, | 116 * Perform dequantization and inverse DCT on one block of coefficients, |
| 114 * producing a reduced-size 4x4 output block. | 117 * producing a reduced-size 4x4 output block. |
| 115 */ | 118 */ |
| 116 | 119 |
| 117 GLOBAL(void) | 120 GLOBAL(void) |
| 118 jpeg_idct_4x4 (j_decompress_ptr cinfo, jpeg_component_info * compptr, | 121 jpeg_idct_4x4 (j_decompress_ptr cinfo, jpeg_component_info *compptr, |
| 119 » JCOEFPTR coef_block, | 122 JCOEFPTR coef_block, |
| 120 » JSAMPARRAY output_buf, JDIMENSION output_col) | 123 JSAMPARRAY output_buf, JDIMENSION output_col) |
| 121 { | 124 { |
| 122 INT32 tmp0, tmp2, tmp10, tmp12; | 125 JLONG tmp0, tmp2, tmp10, tmp12; |
| 123 INT32 z1, z2, z3, z4; | 126 JLONG z1, z2, z3, z4; |
| 124 JCOEFPTR inptr; | 127 JCOEFPTR inptr; |
| 125 ISLOW_MULT_TYPE * quantptr; | 128 ISLOW_MULT_TYPE *quantptr; |
| 126 int * wsptr; | 129 int *wsptr; |
| 127 JSAMPROW outptr; | 130 JSAMPROW outptr; |
| 128 JSAMPLE *range_limit = IDCT_range_limit(cinfo); | 131 JSAMPLE *range_limit = IDCT_range_limit(cinfo); |
| 129 int ctr; | 132 int ctr; |
| 130 int workspace[DCTSIZE*4];» /* buffers data between passes */ | 133 int workspace[DCTSIZE*4]; /* buffers data between passes */ |
| 131 SHIFT_TEMPS | 134 SHIFT_TEMPS |
| 132 | 135 |
| 133 /* Pass 1: process columns from input, store into work array. */ | 136 /* Pass 1: process columns from input, store into work array. */ |
| 134 | 137 |
| 135 inptr = coef_block; | 138 inptr = coef_block; |
| 136 quantptr = (ISLOW_MULT_TYPE *) compptr->dct_table; | 139 quantptr = (ISLOW_MULT_TYPE *) compptr->dct_table; |
| 137 wsptr = workspace; | 140 wsptr = workspace; |
| 138 for (ctr = DCTSIZE; ctr > 0; inptr++, quantptr++, wsptr++, ctr--) { | 141 for (ctr = DCTSIZE; ctr > 0; inptr++, quantptr++, wsptr++, ctr--) { |
| 139 /* Don't bother to process column 4, because second pass won't use it */ | 142 /* Don't bother to process column 4, because second pass won't use it */ |
| 140 if (ctr == DCTSIZE-4) | 143 if (ctr == DCTSIZE-4) |
| 141 continue; | 144 continue; |
| 142 if (inptr[DCTSIZE*1] == 0 && inptr[DCTSIZE*2] == 0 && | 145 if (inptr[DCTSIZE*1] == 0 && inptr[DCTSIZE*2] == 0 && |
| 143 » inptr[DCTSIZE*3] == 0 && inptr[DCTSIZE*5] == 0 && | 146 inptr[DCTSIZE*3] == 0 && inptr[DCTSIZE*5] == 0 && |
| 144 » inptr[DCTSIZE*6] == 0 && inptr[DCTSIZE*7] == 0) { | 147 inptr[DCTSIZE*6] == 0 && inptr[DCTSIZE*7] == 0) { |
| 145 /* AC terms all zero; we need not examine term 4 for 4x4 output */ | 148 /* AC terms all zero; we need not examine term 4 for 4x4 output */ |
| 146 int dcval = DEQUANTIZE(inptr[DCTSIZE*0], quantptr[DCTSIZE*0]) << PASS1_BIT
S; | 149 int dcval = LEFT_SHIFT(DEQUANTIZE(inptr[DCTSIZE*0], quantptr[DCTSIZE*0]), |
| 147 | 150 PASS1_BITS); |
| 151 |
| 148 wsptr[DCTSIZE*0] = dcval; | 152 wsptr[DCTSIZE*0] = dcval; |
| 149 wsptr[DCTSIZE*1] = dcval; | 153 wsptr[DCTSIZE*1] = dcval; |
| 150 wsptr[DCTSIZE*2] = dcval; | 154 wsptr[DCTSIZE*2] = dcval; |
| 151 wsptr[DCTSIZE*3] = dcval; | 155 wsptr[DCTSIZE*3] = dcval; |
| 152 | 156 |
| 153 continue; | 157 continue; |
| 154 } | 158 } |
| 155 | 159 |
| 156 /* Even part */ | 160 /* Even part */ |
| 157 | 161 |
| 158 tmp0 = DEQUANTIZE(inptr[DCTSIZE*0], quantptr[DCTSIZE*0]); | 162 tmp0 = DEQUANTIZE(inptr[DCTSIZE*0], quantptr[DCTSIZE*0]); |
| 159 tmp0 <<= (CONST_BITS+1); | 163 tmp0 = LEFT_SHIFT(tmp0, CONST_BITS+1); |
| 160 | 164 |
| 161 z2 = DEQUANTIZE(inptr[DCTSIZE*2], quantptr[DCTSIZE*2]); | 165 z2 = DEQUANTIZE(inptr[DCTSIZE*2], quantptr[DCTSIZE*2]); |
| 162 z3 = DEQUANTIZE(inptr[DCTSIZE*6], quantptr[DCTSIZE*6]); | 166 z3 = DEQUANTIZE(inptr[DCTSIZE*6], quantptr[DCTSIZE*6]); |
| 163 | 167 |
| 164 tmp2 = MULTIPLY(z2, FIX_1_847759065) + MULTIPLY(z3, - FIX_0_765366865); | 168 tmp2 = MULTIPLY(z2, FIX_1_847759065) + MULTIPLY(z3, - FIX_0_765366865); |
| 165 | 169 |
| 166 tmp10 = tmp0 + tmp2; | 170 tmp10 = tmp0 + tmp2; |
| 167 tmp12 = tmp0 - tmp2; | 171 tmp12 = tmp0 - tmp2; |
| 168 | 172 |
| 169 /* Odd part */ | 173 /* Odd part */ |
| 170 | 174 |
| 171 z1 = DEQUANTIZE(inptr[DCTSIZE*7], quantptr[DCTSIZE*7]); | 175 z1 = DEQUANTIZE(inptr[DCTSIZE*7], quantptr[DCTSIZE*7]); |
| 172 z2 = DEQUANTIZE(inptr[DCTSIZE*5], quantptr[DCTSIZE*5]); | 176 z2 = DEQUANTIZE(inptr[DCTSIZE*5], quantptr[DCTSIZE*5]); |
| 173 z3 = DEQUANTIZE(inptr[DCTSIZE*3], quantptr[DCTSIZE*3]); | 177 z3 = DEQUANTIZE(inptr[DCTSIZE*3], quantptr[DCTSIZE*3]); |
| 174 z4 = DEQUANTIZE(inptr[DCTSIZE*1], quantptr[DCTSIZE*1]); | 178 z4 = DEQUANTIZE(inptr[DCTSIZE*1], quantptr[DCTSIZE*1]); |
| 175 | 179 |
| 176 tmp0 = MULTIPLY(z1, - FIX_0_211164243) /* sqrt(2) * (c3-c1) */ | 180 tmp0 = MULTIPLY(z1, - FIX_0_211164243) /* sqrt(2) * (c3-c1) */ |
| 177 » + MULTIPLY(z2, FIX_1_451774981) /* sqrt(2) * (c3+c7) */ | 181 + MULTIPLY(z2, FIX_1_451774981) /* sqrt(2) * (c3+c7) */ |
| 178 » + MULTIPLY(z3, - FIX_2_172734803) /* sqrt(2) * (-c1-c5) */ | 182 + MULTIPLY(z3, - FIX_2_172734803) /* sqrt(2) * (-c1-c5) */ |
| 179 » + MULTIPLY(z4, FIX_1_061594337); /* sqrt(2) * (c5+c7) */ | 183 + MULTIPLY(z4, FIX_1_061594337); /* sqrt(2) * (c5+c7) */ |
| 180 | 184 |
| 181 tmp2 = MULTIPLY(z1, - FIX_0_509795579) /* sqrt(2) * (c7-c5) */ | 185 tmp2 = MULTIPLY(z1, - FIX_0_509795579) /* sqrt(2) * (c7-c5) */ |
| 182 » + MULTIPLY(z2, - FIX_0_601344887) /* sqrt(2) * (c5-c1) */ | 186 + MULTIPLY(z2, - FIX_0_601344887) /* sqrt(2) * (c5-c1) */ |
| 183 » + MULTIPLY(z3, FIX_0_899976223) /* sqrt(2) * (c3-c7) */ | 187 + MULTIPLY(z3, FIX_0_899976223) /* sqrt(2) * (c3-c7) */ |
| 184 » + MULTIPLY(z4, FIX_2_562915447); /* sqrt(2) * (c1+c3) */ | 188 + MULTIPLY(z4, FIX_2_562915447); /* sqrt(2) * (c1+c3) */ |
| 185 | 189 |
| 186 /* Final output stage */ | 190 /* Final output stage */ |
| 187 | 191 |
| 188 wsptr[DCTSIZE*0] = (int) DESCALE(tmp10 + tmp2, CONST_BITS-PASS1_BITS+1); | 192 wsptr[DCTSIZE*0] = (int) DESCALE(tmp10 + tmp2, CONST_BITS-PASS1_BITS+1); |
| 189 wsptr[DCTSIZE*3] = (int) DESCALE(tmp10 - tmp2, CONST_BITS-PASS1_BITS+1); | 193 wsptr[DCTSIZE*3] = (int) DESCALE(tmp10 - tmp2, CONST_BITS-PASS1_BITS+1); |
| 190 wsptr[DCTSIZE*1] = (int) DESCALE(tmp12 + tmp0, CONST_BITS-PASS1_BITS+1); | 194 wsptr[DCTSIZE*1] = (int) DESCALE(tmp12 + tmp0, CONST_BITS-PASS1_BITS+1); |
| 191 wsptr[DCTSIZE*2] = (int) DESCALE(tmp12 - tmp0, CONST_BITS-PASS1_BITS+1); | 195 wsptr[DCTSIZE*2] = (int) DESCALE(tmp12 - tmp0, CONST_BITS-PASS1_BITS+1); |
| 192 } | 196 } |
| 193 | 197 |
| 194 /* Pass 2: process 4 rows from work array, store into output array. */ | 198 /* Pass 2: process 4 rows from work array, store into output array. */ |
| 195 | 199 |
| 196 wsptr = workspace; | 200 wsptr = workspace; |
| 197 for (ctr = 0; ctr < 4; ctr++) { | 201 for (ctr = 0; ctr < 4; ctr++) { |
| 198 outptr = output_buf[ctr] + output_col; | 202 outptr = output_buf[ctr] + output_col; |
| 199 /* It's not clear whether a zero row test is worthwhile here ... */ | 203 /* It's not clear whether a zero row test is worthwhile here ... */ |
| 200 | 204 |
| 201 #ifndef NO_ZERO_ROW_TEST | 205 #ifndef NO_ZERO_ROW_TEST |
| 202 if (wsptr[1] == 0 && wsptr[2] == 0 && wsptr[3] == 0 && | 206 if (wsptr[1] == 0 && wsptr[2] == 0 && wsptr[3] == 0 && |
| 203 » wsptr[5] == 0 && wsptr[6] == 0 && wsptr[7] == 0) { | 207 wsptr[5] == 0 && wsptr[6] == 0 && wsptr[7] == 0) { |
| 204 /* AC terms all zero */ | 208 /* AC terms all zero */ |
| 205 JSAMPLE dcval = range_limit[(int) DESCALE((INT32) wsptr[0], PASS1_BITS+3) | 209 JSAMPLE dcval = range_limit[(int) DESCALE((JLONG) wsptr[0], PASS1_BITS+3) |
| 206 » » » » & RANGE_MASK]; | 210 & RANGE_MASK]; |
| 207 | 211 |
| 208 outptr[0] = dcval; | 212 outptr[0] = dcval; |
| 209 outptr[1] = dcval; | 213 outptr[1] = dcval; |
| 210 outptr[2] = dcval; | 214 outptr[2] = dcval; |
| 211 outptr[3] = dcval; | 215 outptr[3] = dcval; |
| 212 | 216 |
| 213 wsptr += DCTSIZE;»» /* advance pointer to next row */ | 217 wsptr += DCTSIZE; /* advance pointer to next row */ |
| 214 continue; | 218 continue; |
| 215 } | 219 } |
| 216 #endif | 220 #endif |
| 217 | 221 |
| 218 /* Even part */ | 222 /* Even part */ |
| 219 | 223 |
| 220 tmp0 = ((INT32) wsptr[0]) << (CONST_BITS+1); | 224 tmp0 = LEFT_SHIFT((JLONG) wsptr[0], CONST_BITS+1); |
| 221 | 225 |
| 222 tmp2 = MULTIPLY((INT32) wsptr[2], FIX_1_847759065) | 226 tmp2 = MULTIPLY((JLONG) wsptr[2], FIX_1_847759065) |
| 223 » + MULTIPLY((INT32) wsptr[6], - FIX_0_765366865); | 227 + MULTIPLY((JLONG) wsptr[6], - FIX_0_765366865); |
| 224 | 228 |
| 225 tmp10 = tmp0 + tmp2; | 229 tmp10 = tmp0 + tmp2; |
| 226 tmp12 = tmp0 - tmp2; | 230 tmp12 = tmp0 - tmp2; |
| 227 | 231 |
| 228 /* Odd part */ | 232 /* Odd part */ |
| 229 | 233 |
| 230 z1 = (INT32) wsptr[7]; | 234 z1 = (JLONG) wsptr[7]; |
| 231 z2 = (INT32) wsptr[5]; | 235 z2 = (JLONG) wsptr[5]; |
| 232 z3 = (INT32) wsptr[3]; | 236 z3 = (JLONG) wsptr[3]; |
| 233 z4 = (INT32) wsptr[1]; | 237 z4 = (JLONG) wsptr[1]; |
| 234 | 238 |
| 235 tmp0 = MULTIPLY(z1, - FIX_0_211164243) /* sqrt(2) * (c3-c1) */ | 239 tmp0 = MULTIPLY(z1, - FIX_0_211164243) /* sqrt(2) * (c3-c1) */ |
| 236 » + MULTIPLY(z2, FIX_1_451774981) /* sqrt(2) * (c3+c7) */ | 240 + MULTIPLY(z2, FIX_1_451774981) /* sqrt(2) * (c3+c7) */ |
| 237 » + MULTIPLY(z3, - FIX_2_172734803) /* sqrt(2) * (-c1-c5) */ | 241 + MULTIPLY(z3, - FIX_2_172734803) /* sqrt(2) * (-c1-c5) */ |
| 238 » + MULTIPLY(z4, FIX_1_061594337); /* sqrt(2) * (c5+c7) */ | 242 + MULTIPLY(z4, FIX_1_061594337); /* sqrt(2) * (c5+c7) */ |
| 239 | 243 |
| 240 tmp2 = MULTIPLY(z1, - FIX_0_509795579) /* sqrt(2) * (c7-c5) */ | 244 tmp2 = MULTIPLY(z1, - FIX_0_509795579) /* sqrt(2) * (c7-c5) */ |
| 241 » + MULTIPLY(z2, - FIX_0_601344887) /* sqrt(2) * (c5-c1) */ | 245 + MULTIPLY(z2, - FIX_0_601344887) /* sqrt(2) * (c5-c1) */ |
| 242 » + MULTIPLY(z3, FIX_0_899976223) /* sqrt(2) * (c3-c7) */ | 246 + MULTIPLY(z3, FIX_0_899976223) /* sqrt(2) * (c3-c7) */ |
| 243 » + MULTIPLY(z4, FIX_2_562915447); /* sqrt(2) * (c1+c3) */ | 247 + MULTIPLY(z4, FIX_2_562915447); /* sqrt(2) * (c1+c3) */ |
| 244 | 248 |
| 245 /* Final output stage */ | 249 /* Final output stage */ |
| 246 | 250 |
| 247 outptr[0] = range_limit[(int) DESCALE(tmp10 + tmp2, | 251 outptr[0] = range_limit[(int) DESCALE(tmp10 + tmp2, |
| 248 » » » » » CONST_BITS+PASS1_BITS+3+1) | 252 CONST_BITS+PASS1_BITS+3+1) |
| 249 » » » & RANGE_MASK]; | 253 & RANGE_MASK]; |
| 250 outptr[3] = range_limit[(int) DESCALE(tmp10 - tmp2, | 254 outptr[3] = range_limit[(int) DESCALE(tmp10 - tmp2, |
| 251 » » » » » CONST_BITS+PASS1_BITS+3+1) | 255 CONST_BITS+PASS1_BITS+3+1) |
| 252 » » » & RANGE_MASK]; | 256 & RANGE_MASK]; |
| 253 outptr[1] = range_limit[(int) DESCALE(tmp12 + tmp0, | 257 outptr[1] = range_limit[(int) DESCALE(tmp12 + tmp0, |
| 254 » » » » » CONST_BITS+PASS1_BITS+3+1) | 258 CONST_BITS+PASS1_BITS+3+1) |
| 255 » » » & RANGE_MASK]; | 259 & RANGE_MASK]; |
| 256 outptr[2] = range_limit[(int) DESCALE(tmp12 - tmp0, | 260 outptr[2] = range_limit[(int) DESCALE(tmp12 - tmp0, |
| 257 » » » » » CONST_BITS+PASS1_BITS+3+1) | 261 CONST_BITS+PASS1_BITS+3+1) |
| 258 » » » & RANGE_MASK]; | 262 & RANGE_MASK]; |
| 259 | 263 |
| 260 wsptr += DCTSIZE;» » /* advance pointer to next row */ | 264 wsptr += DCTSIZE; /* advance pointer to next row */ |
| 261 } | 265 } |
| 262 } | 266 } |
| 263 | 267 |
| 264 | 268 |
| 265 /* | 269 /* |
| 266 * Perform dequantization and inverse DCT on one block of coefficients, | 270 * Perform dequantization and inverse DCT on one block of coefficients, |
| 267 * producing a reduced-size 2x2 output block. | 271 * producing a reduced-size 2x2 output block. |
| 268 */ | 272 */ |
| 269 | 273 |
| 270 GLOBAL(void) | 274 GLOBAL(void) |
| 271 jpeg_idct_2x2 (j_decompress_ptr cinfo, jpeg_component_info * compptr, | 275 jpeg_idct_2x2 (j_decompress_ptr cinfo, jpeg_component_info *compptr, |
| 272 » JCOEFPTR coef_block, | 276 JCOEFPTR coef_block, |
| 273 » JSAMPARRAY output_buf, JDIMENSION output_col) | 277 JSAMPARRAY output_buf, JDIMENSION output_col) |
| 274 { | 278 { |
| 275 INT32 tmp0, tmp10, z1; | 279 JLONG tmp0, tmp10, z1; |
| 276 JCOEFPTR inptr; | 280 JCOEFPTR inptr; |
| 277 ISLOW_MULT_TYPE * quantptr; | 281 ISLOW_MULT_TYPE *quantptr; |
| 278 int * wsptr; | 282 int *wsptr; |
| 279 JSAMPROW outptr; | 283 JSAMPROW outptr; |
| 280 JSAMPLE *range_limit = IDCT_range_limit(cinfo); | 284 JSAMPLE *range_limit = IDCT_range_limit(cinfo); |
| 281 int ctr; | 285 int ctr; |
| 282 int workspace[DCTSIZE*2];» /* buffers data between passes */ | 286 int workspace[DCTSIZE*2]; /* buffers data between passes */ |
| 283 SHIFT_TEMPS | 287 SHIFT_TEMPS |
| 284 | 288 |
| 285 /* Pass 1: process columns from input, store into work array. */ | 289 /* Pass 1: process columns from input, store into work array. */ |
| 286 | 290 |
| 287 inptr = coef_block; | 291 inptr = coef_block; |
| 288 quantptr = (ISLOW_MULT_TYPE *) compptr->dct_table; | 292 quantptr = (ISLOW_MULT_TYPE *) compptr->dct_table; |
| 289 wsptr = workspace; | 293 wsptr = workspace; |
| 290 for (ctr = DCTSIZE; ctr > 0; inptr++, quantptr++, wsptr++, ctr--) { | 294 for (ctr = DCTSIZE; ctr > 0; inptr++, quantptr++, wsptr++, ctr--) { |
| 291 /* Don't bother to process columns 2,4,6 */ | 295 /* Don't bother to process columns 2,4,6 */ |
| 292 if (ctr == DCTSIZE-2 || ctr == DCTSIZE-4 || ctr == DCTSIZE-6) | 296 if (ctr == DCTSIZE-2 || ctr == DCTSIZE-4 || ctr == DCTSIZE-6) |
| 293 continue; | 297 continue; |
| 294 if (inptr[DCTSIZE*1] == 0 && inptr[DCTSIZE*3] == 0 && | 298 if (inptr[DCTSIZE*1] == 0 && inptr[DCTSIZE*3] == 0 && |
| 295 » inptr[DCTSIZE*5] == 0 && inptr[DCTSIZE*7] == 0) { | 299 inptr[DCTSIZE*5] == 0 && inptr[DCTSIZE*7] == 0) { |
| 296 /* AC terms all zero; we need not examine terms 2,4,6 for 2x2 output */ | 300 /* AC terms all zero; we need not examine terms 2,4,6 for 2x2 output */ |
| 297 int dcval = DEQUANTIZE(inptr[DCTSIZE*0], quantptr[DCTSIZE*0]) << PASS1_BIT
S; | 301 int dcval = LEFT_SHIFT(DEQUANTIZE(inptr[DCTSIZE*0], quantptr[DCTSIZE*0]), |
| 298 | 302 PASS1_BITS); |
| 303 |
| 299 wsptr[DCTSIZE*0] = dcval; | 304 wsptr[DCTSIZE*0] = dcval; |
| 300 wsptr[DCTSIZE*1] = dcval; | 305 wsptr[DCTSIZE*1] = dcval; |
| 301 | 306 |
| 302 continue; | 307 continue; |
| 303 } | 308 } |
| 304 | 309 |
| 305 /* Even part */ | 310 /* Even part */ |
| 306 | 311 |
| 307 z1 = DEQUANTIZE(inptr[DCTSIZE*0], quantptr[DCTSIZE*0]); | 312 z1 = DEQUANTIZE(inptr[DCTSIZE*0], quantptr[DCTSIZE*0]); |
| 308 tmp10 = z1 << (CONST_BITS+2); | 313 tmp10 = LEFT_SHIFT(z1, CONST_BITS+2); |
| 309 | 314 |
| 310 /* Odd part */ | 315 /* Odd part */ |
| 311 | 316 |
| 312 z1 = DEQUANTIZE(inptr[DCTSIZE*7], quantptr[DCTSIZE*7]); | 317 z1 = DEQUANTIZE(inptr[DCTSIZE*7], quantptr[DCTSIZE*7]); |
| 313 tmp0 = MULTIPLY(z1, - FIX_0_720959822); /* sqrt(2) * (c7-c5+c3-c1) */ | 318 tmp0 = MULTIPLY(z1, - FIX_0_720959822); /* sqrt(2) * (c7-c5+c3-c1) */ |
| 314 z1 = DEQUANTIZE(inptr[DCTSIZE*5], quantptr[DCTSIZE*5]); | 319 z1 = DEQUANTIZE(inptr[DCTSIZE*5], quantptr[DCTSIZE*5]); |
| 315 tmp0 += MULTIPLY(z1, FIX_0_850430095); /* sqrt(2) * (-c1+c3+c5+c7) */ | 320 tmp0 += MULTIPLY(z1, FIX_0_850430095); /* sqrt(2) * (-c1+c3+c5+c7) */ |
| 316 z1 = DEQUANTIZE(inptr[DCTSIZE*3], quantptr[DCTSIZE*3]); | 321 z1 = DEQUANTIZE(inptr[DCTSIZE*3], quantptr[DCTSIZE*3]); |
| 317 tmp0 += MULTIPLY(z1, - FIX_1_272758580); /* sqrt(2) * (-c1+c3-c5-c7) */ | 322 tmp0 += MULTIPLY(z1, - FIX_1_272758580); /* sqrt(2) * (-c1+c3-c5-c7) */ |
| 318 z1 = DEQUANTIZE(inptr[DCTSIZE*1], quantptr[DCTSIZE*1]); | 323 z1 = DEQUANTIZE(inptr[DCTSIZE*1], quantptr[DCTSIZE*1]); |
| 319 tmp0 += MULTIPLY(z1, FIX_3_624509785); /* sqrt(2) * (c1+c3+c5+c7) */ | 324 tmp0 += MULTIPLY(z1, FIX_3_624509785); /* sqrt(2) * (c1+c3+c5+c7) */ |
| 320 | 325 |
| 321 /* Final output stage */ | 326 /* Final output stage */ |
| 322 | 327 |
| 323 wsptr[DCTSIZE*0] = (int) DESCALE(tmp10 + tmp0, CONST_BITS-PASS1_BITS+2); | 328 wsptr[DCTSIZE*0] = (int) DESCALE(tmp10 + tmp0, CONST_BITS-PASS1_BITS+2); |
| 324 wsptr[DCTSIZE*1] = (int) DESCALE(tmp10 - tmp0, CONST_BITS-PASS1_BITS+2); | 329 wsptr[DCTSIZE*1] = (int) DESCALE(tmp10 - tmp0, CONST_BITS-PASS1_BITS+2); |
| 325 } | 330 } |
| 326 | 331 |
| 327 /* Pass 2: process 2 rows from work array, store into output array. */ | 332 /* Pass 2: process 2 rows from work array, store into output array. */ |
| 328 | 333 |
| 329 wsptr = workspace; | 334 wsptr = workspace; |
| 330 for (ctr = 0; ctr < 2; ctr++) { | 335 for (ctr = 0; ctr < 2; ctr++) { |
| 331 outptr = output_buf[ctr] + output_col; | 336 outptr = output_buf[ctr] + output_col; |
| 332 /* It's not clear whether a zero row test is worthwhile here ... */ | 337 /* It's not clear whether a zero row test is worthwhile here ... */ |
| 333 | 338 |
| 334 #ifndef NO_ZERO_ROW_TEST | 339 #ifndef NO_ZERO_ROW_TEST |
| 335 if (wsptr[1] == 0 && wsptr[3] == 0 && wsptr[5] == 0 && wsptr[7] == 0) { | 340 if (wsptr[1] == 0 && wsptr[3] == 0 && wsptr[5] == 0 && wsptr[7] == 0) { |
| 336 /* AC terms all zero */ | 341 /* AC terms all zero */ |
| 337 JSAMPLE dcval = range_limit[(int) DESCALE((INT32) wsptr[0], PASS1_BITS+3) | 342 JSAMPLE dcval = range_limit[(int) DESCALE((JLONG) wsptr[0], PASS1_BITS+3) |
| 338 » » » » & RANGE_MASK]; | 343 & RANGE_MASK]; |
| 339 | 344 |
| 340 outptr[0] = dcval; | 345 outptr[0] = dcval; |
| 341 outptr[1] = dcval; | 346 outptr[1] = dcval; |
| 342 | 347 |
| 343 wsptr += DCTSIZE;»» /* advance pointer to next row */ | 348 wsptr += DCTSIZE; /* advance pointer to next row */ |
| 344 continue; | 349 continue; |
| 345 } | 350 } |
| 346 #endif | 351 #endif |
| 347 | 352 |
| 348 /* Even part */ | 353 /* Even part */ |
| 349 | 354 |
| 350 tmp10 = ((INT32) wsptr[0]) << (CONST_BITS+2); | 355 tmp10 = LEFT_SHIFT((JLONG) wsptr[0], CONST_BITS+2); |
| 351 | 356 |
| 352 /* Odd part */ | 357 /* Odd part */ |
| 353 | 358 |
| 354 tmp0 = MULTIPLY((INT32) wsptr[7], - FIX_0_720959822) /* sqrt(2) * (c7-c5+c3-
c1) */ | 359 tmp0 = MULTIPLY((JLONG) wsptr[7], - FIX_0_720959822) /* sqrt(2) * (c7-c5+c3-
c1) */ |
| 355 » + MULTIPLY((INT32) wsptr[5], FIX_0_850430095) /* sqrt(2) * (-c1+c3+c5+c
7) */ | 360 + MULTIPLY((JLONG) wsptr[5], FIX_0_850430095) /* sqrt(2) * (-c1+c3+c5+c
7) */ |
| 356 » + MULTIPLY((INT32) wsptr[3], - FIX_1_272758580) /* sqrt(2) * (-c1+c3-c5
-c7) */ | 361 + MULTIPLY((JLONG) wsptr[3], - FIX_1_272758580) /* sqrt(2) * (-c1+c3-c5
-c7) */ |
| 357 » + MULTIPLY((INT32) wsptr[1], FIX_3_624509785); /* sqrt(2) * (c1+c3+c5+c
7) */ | 362 + MULTIPLY((JLONG) wsptr[1], FIX_3_624509785); /* sqrt(2) * (c1+c3+c5+c
7) */ |
| 358 | 363 |
| 359 /* Final output stage */ | 364 /* Final output stage */ |
| 360 | 365 |
| 361 outptr[0] = range_limit[(int) DESCALE(tmp10 + tmp0, | 366 outptr[0] = range_limit[(int) DESCALE(tmp10 + tmp0, |
| 362 » » » » » CONST_BITS+PASS1_BITS+3+2) | 367 CONST_BITS+PASS1_BITS+3+2) |
| 363 » » » & RANGE_MASK]; | 368 & RANGE_MASK]; |
| 364 outptr[1] = range_limit[(int) DESCALE(tmp10 - tmp0, | 369 outptr[1] = range_limit[(int) DESCALE(tmp10 - tmp0, |
| 365 » » » » » CONST_BITS+PASS1_BITS+3+2) | 370 CONST_BITS+PASS1_BITS+3+2) |
| 366 » » » & RANGE_MASK]; | 371 & RANGE_MASK]; |
| 367 | 372 |
| 368 wsptr += DCTSIZE;» » /* advance pointer to next row */ | 373 wsptr += DCTSIZE; /* advance pointer to next row */ |
| 369 } | 374 } |
| 370 } | 375 } |
| 371 | 376 |
| 372 | 377 |
| 373 /* | 378 /* |
| 374 * Perform dequantization and inverse DCT on one block of coefficients, | 379 * Perform dequantization and inverse DCT on one block of coefficients, |
| 375 * producing a reduced-size 1x1 output block. | 380 * producing a reduced-size 1x1 output block. |
| 376 */ | 381 */ |
| 377 | 382 |
| 378 GLOBAL(void) | 383 GLOBAL(void) |
| 379 jpeg_idct_1x1 (j_decompress_ptr cinfo, jpeg_component_info * compptr, | 384 jpeg_idct_1x1 (j_decompress_ptr cinfo, jpeg_component_info *compptr, |
| 380 » JCOEFPTR coef_block, | 385 JCOEFPTR coef_block, |
| 381 » JSAMPARRAY output_buf, JDIMENSION output_col) | 386 JSAMPARRAY output_buf, JDIMENSION output_col) |
| 382 { | 387 { |
| 383 int dcval; | 388 int dcval; |
| 384 ISLOW_MULT_TYPE * quantptr; | 389 ISLOW_MULT_TYPE *quantptr; |
| 385 JSAMPLE *range_limit = IDCT_range_limit(cinfo); | 390 JSAMPLE *range_limit = IDCT_range_limit(cinfo); |
| 386 SHIFT_TEMPS | 391 SHIFT_TEMPS |
| 387 | 392 |
| 388 /* We hardly need an inverse DCT routine for this: just take the | 393 /* We hardly need an inverse DCT routine for this: just take the |
| 389 * average pixel value, which is one-eighth of the DC coefficient. | 394 * average pixel value, which is one-eighth of the DC coefficient. |
| 390 */ | 395 */ |
| 391 quantptr = (ISLOW_MULT_TYPE *) compptr->dct_table; | 396 quantptr = (ISLOW_MULT_TYPE *) compptr->dct_table; |
| 392 dcval = DEQUANTIZE(coef_block[0], quantptr[0]); | 397 dcval = DEQUANTIZE(coef_block[0], quantptr[0]); |
| 393 dcval = (int) DESCALE((INT32) dcval, 3); | 398 dcval = (int) DESCALE((JLONG) dcval, 3); |
| 394 | 399 |
| 395 output_buf[0][output_col] = range_limit[dcval & RANGE_MASK]; | 400 output_buf[0][output_col] = range_limit[dcval & RANGE_MASK]; |
| 396 } | 401 } |
| 397 | 402 |
| 398 #endif /* IDCT_SCALING_SUPPORTED */ | 403 #endif /* IDCT_SCALING_SUPPORTED */ |
| OLD | NEW |