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Diffstat (limited to '')
-rw-r--r-- | libjpegtwrp/jidctred.c | 398 |
1 files changed, 0 insertions, 398 deletions
diff --git a/libjpegtwrp/jidctred.c b/libjpegtwrp/jidctred.c deleted file mode 100644 index 421f3c7ca..000000000 --- a/libjpegtwrp/jidctred.c +++ /dev/null @@ -1,398 +0,0 @@ -/* - * jidctred.c - * - * Copyright (C) 1994-1998, Thomas G. Lane. - * This file is part of the Independent JPEG Group's software. - * For conditions of distribution and use, see the accompanying README file. - * - * This file contains inverse-DCT routines that produce reduced-size output: - * either 4x4, 2x2, or 1x1 pixels from an 8x8 DCT block. - * - * The implementation is based on the Loeffler, Ligtenberg and Moschytz (LL&M) - * algorithm used in jidctint.c. We simply replace each 8-to-8 1-D IDCT step - * with an 8-to-4 step that produces the four averages of two adjacent outputs - * (or an 8-to-2 step producing two averages of four outputs, for 2x2 output). - * These steps were derived by computing the corresponding values at the end - * of the normal LL&M code, then simplifying as much as possible. - * - * 1x1 is trivial: just take the DC coefficient divided by 8. - * - * See jidctint.c for additional comments. - */ - -#define JPEG_INTERNALS -#include "jinclude.h" -#include "jpeglib.h" -#include "jdct.h" /* Private declarations for DCT subsystem */ - -#ifdef IDCT_SCALING_SUPPORTED - - -/* - * This module is specialized to the case DCTSIZE = 8. - */ - -#if DCTSIZE != 8 - Sorry, this code only copes with 8x8 DCTs. /* deliberate syntax err */ -#endif - - -/* Scaling is the same as in jidctint.c. */ - -#if BITS_IN_JSAMPLE == 8 -#define CONST_BITS 13 -#define PASS1_BITS 2 -#else -#define CONST_BITS 13 -#define PASS1_BITS 1 /* lose a little precision to avoid overflow */ -#endif - -/* Some C compilers fail to reduce "FIX(constant)" at compile time, thus - * causing a lot of useless floating-point operations at run time. - * To get around this we use the following pre-calculated constants. - * If you change CONST_BITS you may want to add appropriate values. - * (With a reasonable C compiler, you can just rely on the FIX() macro...) - */ - -#if CONST_BITS == 13 -#define FIX_0_211164243 ((INT32) 1730) /* FIX(0.211164243) */ -#define FIX_0_509795579 ((INT32) 4176) /* FIX(0.509795579) */ -#define FIX_0_601344887 ((INT32) 4926) /* FIX(0.601344887) */ -#define FIX_0_720959822 ((INT32) 5906) /* FIX(0.720959822) */ -#define FIX_0_765366865 ((INT32) 6270) /* FIX(0.765366865) */ -#define FIX_0_850430095 ((INT32) 6967) /* FIX(0.850430095) */ -#define FIX_0_899976223 ((INT32) 7373) /* FIX(0.899976223) */ -#define FIX_1_061594337 ((INT32) 8697) /* FIX(1.061594337) */ -#define FIX_1_272758580 ((INT32) 10426) /* FIX(1.272758580) */ -#define FIX_1_451774981 ((INT32) 11893) /* FIX(1.451774981) */ -#define FIX_1_847759065 ((INT32) 15137) /* FIX(1.847759065) */ -#define FIX_2_172734803 ((INT32) 17799) /* FIX(2.172734803) */ -#define FIX_2_562915447 ((INT32) 20995) /* FIX(2.562915447) */ -#define FIX_3_624509785 ((INT32) 29692) /* FIX(3.624509785) */ -#else -#define FIX_0_211164243 FIX(0.211164243) -#define FIX_0_509795579 FIX(0.509795579) -#define FIX_0_601344887 FIX(0.601344887) -#define FIX_0_720959822 FIX(0.720959822) -#define FIX_0_765366865 FIX(0.765366865) -#define FIX_0_850430095 FIX(0.850430095) -#define FIX_0_899976223 FIX(0.899976223) -#define FIX_1_061594337 FIX(1.061594337) -#define FIX_1_272758580 FIX(1.272758580) -#define FIX_1_451774981 FIX(1.451774981) -#define FIX_1_847759065 FIX(1.847759065) -#define FIX_2_172734803 FIX(2.172734803) -#define FIX_2_562915447 FIX(2.562915447) -#define FIX_3_624509785 FIX(3.624509785) -#endif - - -/* Multiply an INT32 variable by an INT32 constant to yield an INT32 result. - * For 8-bit samples with the recommended scaling, all the variable - * and constant values involved are no more than 16 bits wide, so a - * 16x16->32 bit multiply can be used instead of a full 32x32 multiply. - * For 12-bit samples, a full 32-bit multiplication will be needed. - */ - -#if BITS_IN_JSAMPLE == 8 -#define MULTIPLY(var,const) MULTIPLY16C16(var,const) -#else -#define MULTIPLY(var,const) ((var) * (const)) -#endif - - -/* Dequantize a coefficient by multiplying it by the multiplier-table - * entry; produce an int result. In this module, both inputs and result - * are 16 bits or less, so either int or short multiply will work. - */ - -#define DEQUANTIZE(coef,quantval) (((ISLOW_MULT_TYPE) (coef)) * (quantval)) - - -/* - * Perform dequantization and inverse DCT on one block of coefficients, - * producing a reduced-size 4x4 output block. - */ - -GLOBAL(void) -jpeg_idct_4x4 (j_decompress_ptr cinfo, jpeg_component_info * compptr, - JCOEFPTR coef_block, - JSAMPARRAY output_buf, JDIMENSION output_col) -{ - INT32 tmp0, tmp2, tmp10, tmp12; - INT32 z1, z2, z3, z4; - JCOEFPTR inptr; - ISLOW_MULT_TYPE * quantptr; - int * wsptr; - JSAMPROW outptr; - JSAMPLE *range_limit = IDCT_range_limit(cinfo); - int ctr; - int workspace[DCTSIZE*4]; /* buffers data between passes */ - SHIFT_TEMPS - - /* Pass 1: process columns from input, store into work array. */ - - inptr = coef_block; - quantptr = (ISLOW_MULT_TYPE *) compptr->dct_table; - wsptr = workspace; - for (ctr = DCTSIZE; ctr > 0; inptr++, quantptr++, wsptr++, ctr--) { - /* Don't bother to process column 4, because second pass won't use it */ - if (ctr == DCTSIZE-4) - continue; - if (inptr[DCTSIZE*1] == 0 && inptr[DCTSIZE*2] == 0 && - inptr[DCTSIZE*3] == 0 && inptr[DCTSIZE*5] == 0 && - inptr[DCTSIZE*6] == 0 && inptr[DCTSIZE*7] == 0) { - /* AC terms all zero; we need not examine term 4 for 4x4 output */ - int dcval = DEQUANTIZE(inptr[DCTSIZE*0], quantptr[DCTSIZE*0]) << PASS1_BITS; - - wsptr[DCTSIZE*0] = dcval; - wsptr[DCTSIZE*1] = dcval; - wsptr[DCTSIZE*2] = dcval; - wsptr[DCTSIZE*3] = dcval; - - continue; - } - - /* Even part */ - - tmp0 = DEQUANTIZE(inptr[DCTSIZE*0], quantptr[DCTSIZE*0]); - tmp0 <<= (CONST_BITS+1); - - z2 = DEQUANTIZE(inptr[DCTSIZE*2], quantptr[DCTSIZE*2]); - z3 = DEQUANTIZE(inptr[DCTSIZE*6], quantptr[DCTSIZE*6]); - - tmp2 = MULTIPLY(z2, FIX_1_847759065) + MULTIPLY(z3, - FIX_0_765366865); - - tmp10 = tmp0 + tmp2; - tmp12 = tmp0 - tmp2; - - /* Odd part */ - - z1 = DEQUANTIZE(inptr[DCTSIZE*7], quantptr[DCTSIZE*7]); - z2 = DEQUANTIZE(inptr[DCTSIZE*5], quantptr[DCTSIZE*5]); - z3 = DEQUANTIZE(inptr[DCTSIZE*3], quantptr[DCTSIZE*3]); - z4 = DEQUANTIZE(inptr[DCTSIZE*1], quantptr[DCTSIZE*1]); - - tmp0 = MULTIPLY(z1, - FIX_0_211164243) /* sqrt(2) * (c3-c1) */ - + MULTIPLY(z2, FIX_1_451774981) /* sqrt(2) * (c3+c7) */ - + MULTIPLY(z3, - FIX_2_172734803) /* sqrt(2) * (-c1-c5) */ - + MULTIPLY(z4, FIX_1_061594337); /* sqrt(2) * (c5+c7) */ - - tmp2 = MULTIPLY(z1, - FIX_0_509795579) /* sqrt(2) * (c7-c5) */ - + MULTIPLY(z2, - FIX_0_601344887) /* sqrt(2) * (c5-c1) */ - + MULTIPLY(z3, FIX_0_899976223) /* sqrt(2) * (c3-c7) */ - + MULTIPLY(z4, FIX_2_562915447); /* sqrt(2) * (c1+c3) */ - - /* Final output stage */ - - wsptr[DCTSIZE*0] = (int) DESCALE(tmp10 + tmp2, CONST_BITS-PASS1_BITS+1); - wsptr[DCTSIZE*3] = (int) DESCALE(tmp10 - tmp2, CONST_BITS-PASS1_BITS+1); - wsptr[DCTSIZE*1] = (int) DESCALE(tmp12 + tmp0, CONST_BITS-PASS1_BITS+1); - wsptr[DCTSIZE*2] = (int) DESCALE(tmp12 - tmp0, CONST_BITS-PASS1_BITS+1); - } - - /* Pass 2: process 4 rows from work array, store into output array. */ - - wsptr = workspace; - for (ctr = 0; ctr < 4; ctr++) { - outptr = output_buf[ctr] + output_col; - /* It's not clear whether a zero row test is worthwhile here ... */ - -#ifndef NO_ZERO_ROW_TEST - if (wsptr[1] == 0 && wsptr[2] == 0 && wsptr[3] == 0 && - wsptr[5] == 0 && wsptr[6] == 0 && wsptr[7] == 0) { - /* AC terms all zero */ - JSAMPLE dcval = range_limit[(int) DESCALE((INT32) wsptr[0], PASS1_BITS+3) - & RANGE_MASK]; - - outptr[0] = dcval; - outptr[1] = dcval; - outptr[2] = dcval; - outptr[3] = dcval; - - wsptr += DCTSIZE; /* advance pointer to next row */ - continue; - } -#endif - - /* Even part */ - - tmp0 = ((INT32) wsptr[0]) << (CONST_BITS+1); - - tmp2 = MULTIPLY((INT32) wsptr[2], FIX_1_847759065) - + MULTIPLY((INT32) wsptr[6], - FIX_0_765366865); - - tmp10 = tmp0 + tmp2; - tmp12 = tmp0 - tmp2; - - /* Odd part */ - - z1 = (INT32) wsptr[7]; - z2 = (INT32) wsptr[5]; - z3 = (INT32) wsptr[3]; - z4 = (INT32) wsptr[1]; - - tmp0 = MULTIPLY(z1, - FIX_0_211164243) /* sqrt(2) * (c3-c1) */ - + MULTIPLY(z2, FIX_1_451774981) /* sqrt(2) * (c3+c7) */ - + MULTIPLY(z3, - FIX_2_172734803) /* sqrt(2) * (-c1-c5) */ - + MULTIPLY(z4, FIX_1_061594337); /* sqrt(2) * (c5+c7) */ - - tmp2 = MULTIPLY(z1, - FIX_0_509795579) /* sqrt(2) * (c7-c5) */ - + MULTIPLY(z2, - FIX_0_601344887) /* sqrt(2) * (c5-c1) */ - + MULTIPLY(z3, FIX_0_899976223) /* sqrt(2) * (c3-c7) */ - + MULTIPLY(z4, FIX_2_562915447); /* sqrt(2) * (c1+c3) */ - - /* Final output stage */ - - outptr[0] = range_limit[(int) DESCALE(tmp10 + tmp2, - CONST_BITS+PASS1_BITS+3+1) - & RANGE_MASK]; - outptr[3] = range_limit[(int) DESCALE(tmp10 - tmp2, - CONST_BITS+PASS1_BITS+3+1) - & RANGE_MASK]; - outptr[1] = range_limit[(int) DESCALE(tmp12 + tmp0, - CONST_BITS+PASS1_BITS+3+1) - & RANGE_MASK]; - outptr[2] = range_limit[(int) DESCALE(tmp12 - tmp0, - CONST_BITS+PASS1_BITS+3+1) - & RANGE_MASK]; - - wsptr += DCTSIZE; /* advance pointer to next row */ - } -} - - -/* - * Perform dequantization and inverse DCT on one block of coefficients, - * producing a reduced-size 2x2 output block. - */ - -GLOBAL(void) -jpeg_idct_2x2 (j_decompress_ptr cinfo, jpeg_component_info * compptr, - JCOEFPTR coef_block, - JSAMPARRAY output_buf, JDIMENSION output_col) -{ - INT32 tmp0, tmp10, z1; - JCOEFPTR inptr; - ISLOW_MULT_TYPE * quantptr; - int * wsptr; - JSAMPROW outptr; - JSAMPLE *range_limit = IDCT_range_limit(cinfo); - int ctr; - int workspace[DCTSIZE*2]; /* buffers data between passes */ - SHIFT_TEMPS - - /* Pass 1: process columns from input, store into work array. */ - - inptr = coef_block; - quantptr = (ISLOW_MULT_TYPE *) compptr->dct_table; - wsptr = workspace; - for (ctr = DCTSIZE; ctr > 0; inptr++, quantptr++, wsptr++, ctr--) { - /* Don't bother to process columns 2,4,6 */ - if (ctr == DCTSIZE-2 || ctr == DCTSIZE-4 || ctr == DCTSIZE-6) - continue; - if (inptr[DCTSIZE*1] == 0 && inptr[DCTSIZE*3] == 0 && - inptr[DCTSIZE*5] == 0 && inptr[DCTSIZE*7] == 0) { - /* AC terms all zero; we need not examine terms 2,4,6 for 2x2 output */ - int dcval = DEQUANTIZE(inptr[DCTSIZE*0], quantptr[DCTSIZE*0]) << PASS1_BITS; - - wsptr[DCTSIZE*0] = dcval; - wsptr[DCTSIZE*1] = dcval; - - continue; - } - - /* Even part */ - - z1 = DEQUANTIZE(inptr[DCTSIZE*0], quantptr[DCTSIZE*0]); - tmp10 = z1 << (CONST_BITS+2); - - /* Odd part */ - - z1 = DEQUANTIZE(inptr[DCTSIZE*7], quantptr[DCTSIZE*7]); - tmp0 = MULTIPLY(z1, - FIX_0_720959822); /* sqrt(2) * (c7-c5+c3-c1) */ - z1 = DEQUANTIZE(inptr[DCTSIZE*5], quantptr[DCTSIZE*5]); - tmp0 += MULTIPLY(z1, FIX_0_850430095); /* sqrt(2) * (-c1+c3+c5+c7) */ - z1 = DEQUANTIZE(inptr[DCTSIZE*3], quantptr[DCTSIZE*3]); - tmp0 += MULTIPLY(z1, - FIX_1_272758580); /* sqrt(2) * (-c1+c3-c5-c7) */ - z1 = DEQUANTIZE(inptr[DCTSIZE*1], quantptr[DCTSIZE*1]); - tmp0 += MULTIPLY(z1, FIX_3_624509785); /* sqrt(2) * (c1+c3+c5+c7) */ - - /* Final output stage */ - - wsptr[DCTSIZE*0] = (int) DESCALE(tmp10 + tmp0, CONST_BITS-PASS1_BITS+2); - wsptr[DCTSIZE*1] = (int) DESCALE(tmp10 - tmp0, CONST_BITS-PASS1_BITS+2); - } - - /* Pass 2: process 2 rows from work array, store into output array. */ - - wsptr = workspace; - for (ctr = 0; ctr < 2; ctr++) { - outptr = output_buf[ctr] + output_col; - /* It's not clear whether a zero row test is worthwhile here ... */ - -#ifndef NO_ZERO_ROW_TEST - if (wsptr[1] == 0 && wsptr[3] == 0 && wsptr[5] == 0 && wsptr[7] == 0) { - /* AC terms all zero */ - JSAMPLE dcval = range_limit[(int) DESCALE((INT32) wsptr[0], PASS1_BITS+3) - & RANGE_MASK]; - - outptr[0] = dcval; - outptr[1] = dcval; - - wsptr += DCTSIZE; /* advance pointer to next row */ - continue; - } -#endif - - /* Even part */ - - tmp10 = ((INT32) wsptr[0]) << (CONST_BITS+2); - - /* Odd part */ - - tmp0 = MULTIPLY((INT32) wsptr[7], - FIX_0_720959822) /* sqrt(2) * (c7-c5+c3-c1) */ - + MULTIPLY((INT32) wsptr[5], FIX_0_850430095) /* sqrt(2) * (-c1+c3+c5+c7) */ - + MULTIPLY((INT32) wsptr[3], - FIX_1_272758580) /* sqrt(2) * (-c1+c3-c5-c7) */ - + MULTIPLY((INT32) wsptr[1], FIX_3_624509785); /* sqrt(2) * (c1+c3+c5+c7) */ - - /* Final output stage */ - - outptr[0] = range_limit[(int) DESCALE(tmp10 + tmp0, - CONST_BITS+PASS1_BITS+3+2) - & RANGE_MASK]; - outptr[1] = range_limit[(int) DESCALE(tmp10 - tmp0, - CONST_BITS+PASS1_BITS+3+2) - & RANGE_MASK]; - - wsptr += DCTSIZE; /* advance pointer to next row */ - } -} - - -/* - * Perform dequantization and inverse DCT on one block of coefficients, - * producing a reduced-size 1x1 output block. - */ - -GLOBAL(void) -jpeg_idct_1x1 (j_decompress_ptr cinfo, jpeg_component_info * compptr, - JCOEFPTR coef_block, - JSAMPARRAY output_buf, JDIMENSION output_col) -{ - int dcval; - ISLOW_MULT_TYPE * quantptr; - JSAMPLE *range_limit = IDCT_range_limit(cinfo); - SHIFT_TEMPS - - /* We hardly need an inverse DCT routine for this: just take the - * average pixel value, which is one-eighth of the DC coefficient. - */ - quantptr = (ISLOW_MULT_TYPE *) compptr->dct_table; - dcval = DEQUANTIZE(coef_block[0], quantptr[0]); - dcval = (int) DESCALE((INT32) dcval, 3); - - output_buf[0][output_col] = range_limit[dcval & RANGE_MASK]; -} - -#endif /* IDCT_SCALING_SUPPORTED */ |