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tdemultimedia/mpeglib/lib/mpegplay/jrevdct.cpp

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/*
* jrevdct.c
*
* This file is part of the Independent JPEG Group's software.
* The IJG code is distributed under the terms reproduced here:
*
* LEGAL ISSUES
* ============
*
* In plain English:
*
* 1. We don't promise that this software works. (But if you find any bugs,
* please let us know!)
* 2. You can use this software for whatever you want. You don't have to
* pay us.
* 3. You may not pretend that you wrote this software. If you use it in a
* program, you must acknowledge somewhere in your documentation that
* you've used the IJG code.
*
* In legalese:
*
* The authors make NO WARRANTY or representation, either express or implied,
* with respect to this software, its quality, accuracy, merchantability, or
* fitness for a particular purpose. This software is provided "AS IS", and
* you, its user, assume the entire risk as to its quality and accuracy.
*
* This software is copyright (C) 1991, 1992, Thomas G. Lane.
* All Rights Reserved except as specified below.
*
* Permission is hereby granted to use, copy, modify, and distribute this
* software (or portions thereof) for any purpose, without fee, subject to
* these conditions:
* (1) If any part of the source code for this software is distributed, then
* this copyright and no-warranty notice must be included unaltered; and any
* additions, deletions, or changes to the original files must be clearly
* indicated in accompanying documentation.
* (2) If only executable code is distributed, then the accompanying
* documentation must state that "this software is based in part on the
* work of the Independent JPEG Group".
* (3) Permission for use of this software is granted only if the user
* accepts full responsibility for any undesirable consequences; the authors
* accept NO LIABILITY for damages of any kind.
*
* These conditions apply to any software derived from or based on the IJG
* code, not just to the unmodified library. If you use our work, you ought
* to acknowledge us.
*
* Permission is NOT granted for the use of any IJG author's name or company
* name in advertising or publicity relating to this software or products
* derived from it. This software may be referred to only as
* "the Independent JPEG Group's software".
*
* We specifically permit and encourage the use of this software as the
* basis of commercial products, provided that all warranty or liability
* claims are assumed by the product vendor.
*
*
* ARCHIVE LOCATIONS
* =================
*
* The "official" archive site for this software is ftp.uu.net (Internet
* address 192.48.96.9). The most recent released version can always be
* found there in directory graphics/jpeg. This particular version will
* be archived as graphics/jpeg/jpegsrc.v6a.tar.gz. If you are on the
* Internet, you can retrieve files from ftp.uu.net by standard anonymous
* FTP. If you don't have FTP access, UUNET's archives are also available
* via UUCP; contact help@uunet.uu.net for information on retrieving files
* that way.
*
* Numerous Internet sites maintain copies of the UUNET files. However,
* only ftp.uu.net is guaranteed to have the latest official version.
*
* You can also obtain this software in DOS-compatible "zip" archive
* format from the SimTel archives (ftp.coast.net:/SimTel/msdos/graphics/),
* or on CompuServe in the Graphics Support forum (GO CIS:GRAPHSUP),
* library 12 "JPEG Tools". Again, these versions may sometimes lag behind
* the ftp.uu.net release.
*
* The JPEG FAQ (Frequently Asked Questions) article is a useful source of
* general information about JPEG. It is updated constantly and therefore
* is not included in this distribution. The FAQ is posted every two weeks
* to Usenet newsgroups comp.graphics.misc, news.answers, and other groups.
* You can always obtain the latest version from the news.answers archive
* at rtfm.mit.edu. By FTP, fetch /pub/usenet/news.answers/jpeg-faq/part1
* and .../part2. If you don't have FTP, send e-mail to
* mail-server@rtfm.mit.edu with body
* send usenet/news.answers/jpeg-faq/part1
* send usenet/news.answers/jpeg-faq/part2
*
* ==============
*
*
* This file contains the basic inverse-DCT transformation subroutine.
*
* This implementation is based on an algorithm described in
* C. Loeffler, A. Ligtenberg and G. Moschytz, "Practical Fast 1-D DCT
* Algorithms with 11 Multiplications", Proc. Int'l. Conf. on Acoustics,
* Speech, and Signal Processing 1989 (ICASSP '89), pp. 988-991.
* The primary algorithm described there uses 11 multiplies and 29 adds.
* We use their alternate method with 12 multiplies and 32 adds.
* The advantage of this method is that no data path contains more than one
* multiplication; this allows a very simple and accurate implementation in
* scaled fixed-point arithmetic, with a minimal number of shifts.
*
*
* CHANGES FOR BERKELEY MPEG
* =========================
*
* This file has been altered to use the Berkeley MPEG header files,
* to add the capability to handle sparse DCT matrices efficiently,
* and to relabel the inverse DCT function as well as the file
* (formerly jidctint.c).
*
* I've made lots of modifications to attempt to take advantage of the
* sparse nature of the DCT matrices we're getting. Although the logic
* is cumbersome, it's straightforward and the resulting code is much
* faster.
*
* A better way to do this would be to pass in the DCT block as a sparse
* matrix, perhaps with the difference cases encoded.
*/
#include "jrevdct.h"
/* We assume that right shift corresponds to signed division by 2 with
* rounding towards minus infinity. This is correct for typical "arithmetic
* shift" instructions that shift in copies of the sign bit. But some
* C compilers implement >> with an unsigned shift. For these machines you
* must define RIGHT_SHIFT_IS_UNSIGNED.
* RIGHT_SHIFT provides a proper signed right shift of an INT32 quantity.
* It is only applied with constant shift counts. SHIFT_TEMPS must be
* included in the variables of any routine using RIGHT_SHIFT.
*/
#ifdef RIGHT_SHIFT_IS_UNSIGNED
#define SHIFT_TEMPS INT32 shift_temp;
#define RIGHT_SHIFT(x,shft) \
((shift_temp = (x)) < 0 ? \
(shift_temp >> (shft)) | ((~((INT32) 0)) << (32-(shft))) : \
(shift_temp >> (shft)))
#else
#define SHIFT_TEMPS
#define RIGHT_SHIFT(x,shft) ((x) >> (shft))
#endif
/*
* This routine is specialized to the case DCTSIZE = 8.
*/
#if DCTSIZE != 8
Sorry, this code only copes with 8x8 DCTs. /* deliberate syntax err */
#endif
/*
* A 2-D IDCT can be done by 1-D IDCT on each row followed by 1-D IDCT
* on each column. Direct algorithms are also available, but they are
* much more complex and seem not to be any faster when reduced to code.
*
* The poop on this scaling stuff is as follows:
*
* Each 1-D IDCT step produces outputs which are a factor of sqrt(N)
* larger than the true IDCT outputs. The final outputs are therefore
* a factor of N larger than desired; since N=8 this can be cured by
* a simple right shift at the end of the algorithm. The advantage of
* this arrangement is that we save two multiplications per 1-D IDCT,
* because the y0 and y4 inputs need not be divided by sqrt(N).
*
* We have to do addition and subtraction of the integer inputs, which
* is no problem, and multiplication by fractional constants, which is
* a problem to do in integer arithmetic. We multiply all the constants
* by CONST_SCALE and convert them to integer constants (thus retaining
* CONST_BITS bits of precision in the constants). After doing a
* multiplication we have to divide the product by CONST_SCALE, with proper
* rounding, to produce the correct output. This division can be done
* cheaply as a right shift of CONST_BITS bits. We postpone shifting
* as long as possible so that partial sums can be added together with
* full fractional precision.
*
* The outputs of the first pass are scaled up by PASS1_BITS bits so that
* they are represented to better-than-integral precision. These outputs
* require BITS_IN_JSAMPLE + PASS1_BITS + 3 bits; this fits in a 16-bit word
* with the recommended scaling. (To scale up 12-bit sample data further, an
* intermediate INT32 array would be needed.)
*
* To avoid overflow of the 32-bit intermediate results in pass 2, we must
* have BITS_IN_JSAMPLE + CONST_BITS + PASS1_BITS <= 26. Error analysis
* shows that the values given below are the most effective.
*/
#ifdef EIGHT_BIT_SAMPLES
#define PASS1_BITS 2
#else
#define PASS1_BITS 1 /* lose a little precision to avoid overflow */
#endif
#define ONE ((INT32) 1)
#define CONST_SCALE (ONE << CONST_BITS)
/* Convert a positive real constant to an integer scaled by CONST_SCALE.
* IMPORTANT: if your compiler doesn't do this arithmetic at compile time,
* you will pay a significant penalty in run time. In that case, figure
* the correct integer constant values and insert them by hand.
*/
#define FIX(x) ((INT32) ((x) * CONST_SCALE + 0.5))
/* When adding two opposite-signed fixes, the 0.5 cancels */
#define FIX2(x) ((INT32) ((x) * CONST_SCALE))
/* Descale and correctly round an INT32 value that's scaled by N bits.
* We assume RIGHT_SHIFT rounds towards minus infinity, so adding
* the fudge factor is correct for either sign of X.
*/
#define DESCALE(x,n) RIGHT_SHIFT((x) + (ONE << ((n)-1)), n)
/* 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;
* this provides a useful speedup on many machines.
* There is no way to specify a 16x16->32 multiply in portable C, but
* some C compilers will do the right thing if you provide the correct
* combination of casts.
* NB: for 12-bit samples, a full 32-bit multiplication will be needed.
*/
#ifdef EIGHT_BIT_SAMPLES
#ifdef SHORTxSHORT_32 /* may work if 'int' is 32 bits */
#define MULTIPLY(var,const) (((INT16) (var)) * ((INT16) (const)))
#endif
#ifdef SHORTxLCONST_32 /* known to work with Microsoft C 6.0 */
#define MULTIPLY(var,const) (((INT16) (var)) * ((INT32) (const)))
#endif
#endif
#ifndef MULTIPLY /* default definition */
#define MULTIPLY(var,const) ((var) * (const))
#endif
#ifndef NO_SPARSE_DCT
#define SPARSE_SCALE_FACTOR 8
#endif
/* Precomputed idct value arrays. */
static DCTELEM PreIDCT[64][64];
/*
*--------------------------------------------------------------
*
* init_pre_idct --
*
* Pre-computes singleton coefficient IDCT values.
*
* Results:
* None.
*
* Side effects:
* None.
*
*--------------------------------------------------------------
*/
void init_pre_idct() {
int i;
for (i=0; i<64; i++) {
memset((char *) PreIDCT[i], 0, 64*sizeof(DCTELEM));
PreIDCT[i][i] = 1 << SPARSE_SCALE_FACTOR;
j_rev_dct(PreIDCT[i]);
}
int pos;
int rr;
DCTELEM *ndataptr;
for(pos=0;pos<64;pos++) {
ndataptr = PreIDCT[pos];
for(rr=0; rr<4; rr++) {
for(i=0;i<16;i++) {
ndataptr[i] = ndataptr[i]/256;
}
ndataptr += 16;
}
}
}
#ifndef NO_SPARSE_DCT
/*
*--------------------------------------------------------------
*
* j_rev_dct_sparse --
*
* Performs the inverse DCT on one block of coefficients.
*
* Results:
* None.
*
* Side effects:
* None.
*
*--------------------------------------------------------------
*/
void j_rev_dct_sparse (DCTBLOCK data, int pos) {
short int val;
int *dp;
int v;
int quant;
// cout << "j_rev_dct_sparse"<<endl;
/* If DC Coefficient. */
if (pos == 0) {
dp = (int *)data;
v = *data;
quant = 8;
/* Compute 32 bit value to assign. This speeds things up a bit */
if (v < 0) {
val = -v;
val += (quant / 2);
val /= quant;
val = -val;
}
else {
val = (v + (quant / 2)) / quant;
}
v = ((val & 0xffff) | (val << 16));
dp[0] = v; dp[1] = v; dp[2] = v; dp[3] = v;
dp[4] = v; dp[5] = v; dp[6] = v; dp[7] = v;
dp[8] = v; dp[9] = v; dp[10] = v; dp[11] = v;
dp[12] = v; dp[13] = v; dp[14] = v; dp[15] = v;
dp[16] = v; dp[17] = v; dp[18] = v; dp[19] = v;
dp[20] = v; dp[21] = v; dp[22] = v; dp[23] = v;
dp[24] = v; dp[25] = v; dp[26] = v; dp[27] = v;
dp[28] = v; dp[29] = v; dp[30] = v; dp[31] = v;
return;
}
//printf("sparse is: %d val:%8x\n",pos,data[pos]);
/*
j_rev_dct(data);
return;
*/
/* Some other coefficient. */
DCTELEM *dataptr;
DCTELEM *ndataptr;
int coeff, rr;
dataptr = (DCTELEM *)data;
coeff = dataptr[pos];
ndataptr = PreIDCT[pos];
//printf ("COEFFICIENT = %3d, POSITION = %2d\n", coeff, pos);
coeff=coeff/256;
for (rr=0; rr<4; rr++) {
dataptr[0] = (ndataptr[0] * coeff);
dataptr[1] = (ndataptr[1] * coeff);
dataptr[2] = (ndataptr[2] * coeff);
dataptr[3] = (ndataptr[3] * coeff);
dataptr[4] = (ndataptr[4] * coeff);
dataptr[5] = (ndataptr[5] * coeff);
dataptr[6] = (ndataptr[6] * coeff);
dataptr[7] = (ndataptr[7] * coeff);
dataptr[8] = (ndataptr[8] * coeff);
dataptr[9] = (ndataptr[9] * coeff);
dataptr[10] = (ndataptr[10] * coeff);
dataptr[11] = (ndataptr[11] * coeff);
dataptr[12] = (ndataptr[12] * coeff);
dataptr[13] = (ndataptr[13] * coeff);
dataptr[14] = (ndataptr[14] * coeff);
dataptr[15] = (ndataptr[15] * coeff);
dataptr += 16;
ndataptr += 16;
}
dataptr = (DCTELEM *) data;
return;
}
#else
/*
*--------------------------------------------------------------
*
* j_rev_dct_sparse --
*
* Performs the original inverse DCT on one block of
* coefficients.
*
* Results:
* None.
*
* Side effects:
* None.
*
*--------------------------------------------------------------
*/
void j_rev_dct_sparse (DCTBLOCK data,int pos) {
j_rev_dct(data);
}
#endif /* SPARSE_DCT */
#ifndef FIVE_DCT
#ifndef ORIG_DCT
/*
*--------------------------------------------------------------
*
* j_rev_dct --
*
* The inverse DCT function.
*
* Results:
* None.
*
* Side effects:
* None.
*
*--------------------------------------------------------------
*/
void j_rev_dct (DCTBLOCK data) {
INT32 tmp0, tmp1, tmp2, tmp3;
INT32 tmp10, tmp11, tmp12, tmp13;
INT32 z1, z2, z3, z4, z5;
INT32 d0, d1, d2, d3, d4, d5, d6, d7;
DCTELEM *dataptr;
int rowctr;
SHIFT_TEMPS
/* Pass 1: process rows. */
/* Note results are scaled up by sqrt(8) compared to a true IDCT; */
/* furthermore, we scale the results by 2**PASS1_BITS. */
dataptr = data;
for (rowctr = DCTSIZE-1; rowctr >= 0; rowctr--) {
/* Due to quantization, we will usually find that many of the input
* coefficients are zero, especially the AC terms. We can exploit this
* by short-circuiting the IDCT calculation for any row in which all
* the AC terms are zero. In that case each output is equal to the
* DC coefficient (with scale factor as needed).
* With typical images and quantization tables, half or more of the
* row DCT calculations can be simplified this way.
*/
int *idataptr = (int*)dataptr;
d0 = dataptr[0];
d1 = dataptr[1];
if ((d1 == 0) && (idataptr[1] + idataptr[2] + idataptr[3]) == 0) {
/* AC terms all zero */
if (d0) {
/* Compute a 32 bit value to assign. */
DCTELEM dcval = (DCTELEM) (d0 << PASS1_BITS);
int v = (dcval & 0xffff) + (dcval << 16);
idataptr[0] = v;
idataptr[1] = v;
idataptr[2] = v;
idataptr[3] = v;
}
dataptr += DCTSIZE; /* advance pointer to next row */
continue;
}
d2 = dataptr[2];
d3 = dataptr[3];
d4 = dataptr[4];
d5 = dataptr[5];
d6 = dataptr[6];
d7 = dataptr[7];
/* Even part: reverse the even part of the forward DCT. */
/* The rotator is sqrt(2)*c(-6). */
if (d6) {
if (d4) {
if (d2) {
if (d0) {
/* d0 != 0, d2 != 0, d4 != 0, d6 != 0 */
z1 = MULTIPLY(d2 + d6, FIX(0.541196100));
tmp2 = z1 + MULTIPLY(d6, - FIX(1.847759065));
tmp3 = z1 + MULTIPLY(d2, FIX(0.765366865));
tmp0 = (d0 + d4) << CONST_BITS;
tmp1 = (d0 - d4) << CONST_BITS;
tmp10 = tmp0 + tmp3;
tmp13 = tmp0 - tmp3;
tmp11 = tmp1 + tmp2;
tmp12 = tmp1 - tmp2;
} else {
/* d0 == 0, d2 != 0, d4 != 0, d6 != 0 */
z1 = MULTIPLY(d2 + d6, FIX(0.541196100));
tmp2 = z1 + MULTIPLY(d6, - FIX(1.847759065));
tmp3 = z1 + MULTIPLY(d2, FIX(0.765366865));
tmp0 = d4 << CONST_BITS;
tmp10 = tmp0 + tmp3;
tmp13 = tmp0 - tmp3;
tmp11 = tmp2 - tmp0;
tmp12 = -(tmp0 + tmp2);
}
} else {
if (d0) {
/* d0 != 0, d2 == 0, d4 != 0, d6 != 0 */
tmp2 = MULTIPLY(d6, - FIX2(1.306562965));
tmp3 = MULTIPLY(d6, FIX(0.541196100));
tmp0 = (d0 + d4) << CONST_BITS;
tmp1 = (d0 - d4) << CONST_BITS;
tmp10 = tmp0 + tmp3;
tmp13 = tmp0 - tmp3;
tmp11 = tmp1 + tmp2;
tmp12 = tmp1 - tmp2;
} else {
/* d0 == 0, d2 == 0, d4 != 0, d6 != 0 */
tmp2 = MULTIPLY(d6, - FIX2(1.306562965));
tmp3 = MULTIPLY(d6, FIX(0.541196100));
tmp0 = d4 << CONST_BITS;
tmp10 = tmp0 + tmp3;
tmp13 = tmp0 - tmp3;
tmp11 = tmp2 - tmp0;
tmp12 = -(tmp0 + tmp2);
}
}
} else {
if (d2) {
if (d0) {
/* d0 != 0, d2 != 0, d4 == 0, d6 != 0 */
z1 = MULTIPLY(d2 + d6, FIX(0.541196100));
tmp2 = z1 + MULTIPLY(d6, - FIX(1.847759065));
tmp3 = z1 + MULTIPLY(d2, FIX(0.765366865));
tmp0 = d0 << CONST_BITS;
tmp10 = tmp0 + tmp3;
tmp13 = tmp0 - tmp3;
tmp11 = tmp0 + tmp2;
tmp12 = tmp0 - tmp2;
} else {
/* d0 == 0, d2 != 0, d4 == 0, d6 != 0 */
z1 = MULTIPLY(d2 + d6, FIX(0.541196100));
tmp2 = z1 + MULTIPLY(d6, - FIX(1.847759065));
tmp3 = z1 + MULTIPLY(d2, FIX(0.765366865));
tmp10 = tmp3;
tmp13 = -tmp3;
tmp11 = tmp2;
tmp12 = -tmp2;
}
} else {
if (d0) {
/* d0 != 0, d2 == 0, d4 == 0, d6 != 0 */
tmp2 = MULTIPLY(d6, - FIX2(1.306562965));
tmp3 = MULTIPLY(d6, FIX(0.541196100));
tmp0 = d0 << CONST_BITS;
tmp10 = tmp0 + tmp3;
tmp13 = tmp0 - tmp3;
tmp11 = tmp0 + tmp2;
tmp12 = tmp0 - tmp2;
} else {
/* d0 == 0, d2 == 0, d4 == 0, d6 != 0 */
tmp2 = MULTIPLY(d6, - FIX2(1.306562965));
tmp3 = MULTIPLY(d6, FIX(0.541196100));
tmp10 = tmp3;
tmp13 = -tmp3;
tmp11 = tmp2;
tmp12 = -tmp2;
}
}
}
} else {
if (d4) {
if (d2) {
if (d0) {
/* d0 != 0, d2 != 0, d4 != 0, d6 == 0 */
tmp2 = MULTIPLY(d2, FIX(0.541196100));
tmp3 = (INT32) (MULTIPLY(d2, (FIX(1.306562965) + .5)));
tmp0 = (d0 + d4) << CONST_BITS;
tmp1 = (d0 - d4) << CONST_BITS;
tmp10 = tmp0 + tmp3;
tmp13 = tmp0 - tmp3;
tmp11 = tmp1 + tmp2;
tmp12 = tmp1 - tmp2;
} else {
/* d0 == 0, d2 != 0, d4 != 0, d6 == 0 */
tmp2 = MULTIPLY(d2, FIX(0.541196100));
tmp3 = (INT32) (MULTIPLY(d2, (FIX(1.306562965) + .5)));
tmp0 = d4 << CONST_BITS;
tmp10 = tmp0 + tmp3;
tmp13 = tmp0 - tmp3;
tmp11 = tmp2 - tmp0;
tmp12 = -(tmp0 + tmp2);
}
} else {
if (d0) {
/* d0 != 0, d2 == 0, d4 != 0, d6 == 0 */
tmp10 = tmp13 = (d0 + d4) << CONST_BITS;
tmp11 = tmp12 = (d0 - d4) << CONST_BITS;
} else {
/* d0 == 0, d2 == 0, d4 != 0, d6 == 0 */
tmp10 = tmp13 = d4 << CONST_BITS;
tmp11 = tmp12 = -tmp10;
}
}
} else {
if (d2) {
if (d0) {
/* d0 != 0, d2 != 0, d4 == 0, d6 == 0 */
tmp2 = MULTIPLY(d2, FIX(0.541196100));
tmp3 = (INT32) (MULTIPLY(d2, (FIX(1.306562965) + .5)));
tmp0 = d0 << CONST_BITS;
tmp10 = tmp0 + tmp3;
tmp13 = tmp0 - tmp3;
tmp11 = tmp0 + tmp2;
tmp12 = tmp0 - tmp2;
} else {
/* d0 == 0, d2 != 0, d4 == 0, d6 == 0 */
tmp2 = MULTIPLY(d2, FIX(0.541196100));
tmp3 = (INT32) (MULTIPLY(d2, (FIX(1.306562965) + .5)));
tmp10 = tmp3;
tmp13 = -tmp3;
tmp11 = tmp2;
tmp12 = -tmp2;
}
} else {
if (d0) {
/* d0 != 0, d2 == 0, d4 == 0, d6 == 0 */
tmp10 = tmp13 = tmp11 = tmp12 = d0 << CONST_BITS;
} else {
/* d0 == 0, d2 == 0, d4 == 0, d6 == 0 */
tmp10 = tmp13 = tmp11 = tmp12 = 0;
}
}
}
}
/* Odd part per figure 8; the matrix is unitary and hence its
* transpose is its inverse. i0..i3 are y7,y5,y3,y1 respectively.
*/
if (d7) {
if (d5) {
if (d3) {
if (d1) {
/* d1 != 0, d3 != 0, d5 != 0, d7 != 0 */
z1 = d7 + d1;
z2 = d5 + d3;
z3 = d7 + d3;
z4 = d5 + d1;
z5 = MULTIPLY(z3 + z4, FIX(1.175875602));
tmp0 = MULTIPLY(d7, FIX(0.298631336));
tmp1 = MULTIPLY(d5, FIX(2.053119869));
tmp2 = MULTIPLY(d3, FIX(3.072711026));
tmp3 = MULTIPLY(d1, FIX(1.501321110));
z1 = MULTIPLY(z1, - FIX(0.899976223));
z2 = MULTIPLY(z2, - FIX(2.562915447));
z3 = MULTIPLY(z3, - FIX(1.961570560));
z4 = MULTIPLY(z4, - FIX(0.390180644));
z3 += z5;
z4 += z5;
tmp0 += z1 + z3;
tmp1 += z2 + z4;
tmp2 += z2 + z3;
tmp3 += z1 + z4;
} else {
/* d1 == 0, d3 != 0, d5 != 0, d7 != 0 */
z2 = d5 + d3;
z3 = d7 + d3;
z5 = MULTIPLY(z3 + d5, FIX(1.175875602));
tmp0 = MULTIPLY(d7, FIX(0.298631336));
tmp1 = MULTIPLY(d5, FIX(2.053119869));
tmp2 = MULTIPLY(d3, FIX(3.072711026));
z1 = MULTIPLY(d7, - FIX(0.899976223));
z2 = MULTIPLY(z2, - FIX(2.562915447));
z3 = MULTIPLY(z3, - FIX(1.961570560));
z4 = MULTIPLY(d5, - FIX(0.390180644));
z3 += z5;
z4 += z5;
tmp0 += z1 + z3;
tmp1 += z2 + z4;
tmp2 += z2 + z3;
tmp3 = z1 + z4;
}
} else {
if (d1) {
/* d1 != 0, d3 == 0, d5 != 0, d7 != 0 */
z1 = d7 + d1;
z4 = d5 + d1;
z5 = MULTIPLY(d7 + z4, FIX(1.175875602));
tmp0 = MULTIPLY(d7, FIX(0.298631336));
tmp1 = MULTIPLY(d5, FIX(2.053119869));
tmp3 = MULTIPLY(d1, FIX(1.501321110));
z1 = MULTIPLY(z1, - FIX(0.899976223));
z2 = MULTIPLY(d5, - FIX(2.562915447));
z3 = MULTIPLY(d7, - FIX(1.961570560));
z4 = MULTIPLY(z4, - FIX(0.390180644));
z3 += z5;
z4 += z5;
tmp0 += z1 + z3;
tmp1 += z2 + z4;
tmp2 = z2 + z3;
tmp3 += z1 + z4;
} else {
/* d1 == 0, d3 == 0, d5 != 0, d7 != 0 */
z5 = MULTIPLY(d7 + d5, FIX(1.175875602));
tmp0 = MULTIPLY(d7, - FIX2(0.601344887));
tmp1 = MULTIPLY(d5, - FIX2(0.509795578));
z1 = MULTIPLY(d7, - FIX(0.899976223));
z3 = MULTIPLY(d7, - FIX(1.961570560));
z2 = MULTIPLY(d5, - FIX(2.562915447));
z4 = MULTIPLY(d5, - FIX(0.390180644));
z3 += z5;
z4 += z5;
tmp0 += z3;
tmp1 += z4;
tmp2 = z2 + z3;
tmp3 = z1 + z4;
}
}
} else {
if (d3) {
if (d1) {
/* d1 != 0, d3 != 0, d5 == 0, d7 != 0 */
z1 = d7 + d1;
z3 = d7 + d3;
z5 = MULTIPLY(z3 + d1, FIX(1.175875602));
tmp0 = MULTIPLY(d7, FIX(0.298631336));
tmp2 = MULTIPLY(d3, FIX(3.072711026));
tmp3 = MULTIPLY(d1, FIX(1.501321110));
z1 = MULTIPLY(z1, - FIX(0.899976223));
z2 = MULTIPLY(d3, - FIX(2.562915447));
z3 = MULTIPLY(z3, - FIX(1.961570560));
z4 = MULTIPLY(d1, - FIX(0.390180644));
z3 += z5;
z4 += z5;
tmp0 += z1 + z3;
tmp1 = z2 + z4;
tmp2 += z2 + z3;
tmp3 += z1 + z4;
} else {
/* d1 == 0, d3 != 0, d5 == 0, d7 != 0 */
z3 = d7 + d3;
z5 = MULTIPLY(z3, FIX(1.175875602));
tmp0 = MULTIPLY(d7, - FIX2(0.601344887));
tmp2 = MULTIPLY(d3, FIX(0.509795579));
z1 = MULTIPLY(d7, - FIX(0.899976223));
z2 = MULTIPLY(d3, - FIX(2.562915447));
z3 = MULTIPLY(z3, - FIX2(0.785694958));
tmp0 += z3;
tmp1 = z2 + z5;
tmp2 += z3;
tmp3 = z1 + z5;
}
} else {
if (d1) {
/* d1 != 0, d3 == 0, d5 == 0, d7 != 0 */
z1 = d7 + d1;
z5 = MULTIPLY(z1, FIX(1.175875602));
tmp0 = MULTIPLY(d7, - FIX2(1.662939224));
tmp3 = MULTIPLY(d1, FIX2(1.111140466));
z1 = MULTIPLY(z1, FIX2(0.275899379));
z3 = MULTIPLY(d7, - FIX(1.961570560));
z4 = MULTIPLY(d1, - FIX(0.390180644));
tmp0 += z1;
tmp1 = z4 + z5;
tmp2 = z3 + z5;
tmp3 += z1;
} else {
/* d1 == 0, d3 == 0, d5 == 0, d7 != 0 */
tmp0 = MULTIPLY(d7, - FIX2(1.387039845));
tmp1 = MULTIPLY(d7, FIX(1.175875602));
tmp2 = MULTIPLY(d7, - FIX2(0.785694958));
tmp3 = MULTIPLY(d7, FIX2(0.275899379));
}
}
}
} else {
if (d5) {
if (d3) {
if (d1) {
/* d1 != 0, d3 != 0, d5 != 0, d7 == 0 */
z2 = d5 + d3;
z4 = d5 + d1;
z5 = MULTIPLY(d3 + z4, FIX(1.175875602));
tmp1 = MULTIPLY(d5, FIX(2.053119869));
tmp2 = MULTIPLY(d3, FIX(3.072711026));
tmp3 = MULTIPLY(d1, FIX(1.501321110));
z1 = MULTIPLY(d1, - FIX(0.899976223));
z2 = MULTIPLY(z2, - FIX(2.562915447));
z3 = MULTIPLY(d3, - FIX(1.961570560));
z4 = MULTIPLY(z4, - FIX(0.390180644));
z3 += z5;
z4 += z5;
tmp0 = z1 + z3;
tmp1 += z2 + z4;
tmp2 += z2 + z3;
tmp3 += z1 + z4;
} else {
/* d1 == 0, d3 != 0, d5 != 0, d7 == 0 */
z2 = d5 + d3;
z5 = MULTIPLY(z2, FIX(1.175875602));
tmp1 = MULTIPLY(d5, FIX2(1.662939225));
tmp2 = MULTIPLY(d3, FIX2(1.111140466));
z2 = MULTIPLY(z2, - FIX2(1.387039845));
z3 = MULTIPLY(d3, - FIX(1.961570560));
z4 = MULTIPLY(d5, - FIX(0.390180644));
tmp0 = z3 + z5;
tmp1 += z2;
tmp2 += z2;
tmp3 = z4 + z5;
}
} else {
if (d1) {
/* d1 != 0, d3 == 0, d5 != 0, d7 == 0 */
z4 = d5 + d1;
z5 = MULTIPLY(z4, FIX(1.175875602));
tmp1 = MULTIPLY(d5, - FIX2(0.509795578));
tmp3 = MULTIPLY(d1, FIX2(0.601344887));
z1 = MULTIPLY(d1, - FIX(0.899976223));
z2 = MULTIPLY(d5, - FIX(2.562915447));
z4 = MULTIPLY(z4, FIX2(0.785694958));
tmp0 = z1 + z5;
tmp2 = z2 + z5;
tmp1 += z4;
tmp3 += z4;
} else {
/* d1 == 0, d3 == 0, d5 != 0, d7 == 0 */
tmp0 = MULTIPLY(d5, FIX(1.175875602));
tmp1 = MULTIPLY(d5, FIX2(0.275899380));
tmp2 = MULTIPLY(d5, - FIX2(1.387039845));
tmp3 = MULTIPLY(d5, FIX2(0.785694958));
}
}
} else {
if (d3) {
if (d1) {
/* d1 != 0, d3 != 0, d5 == 0, d7 == 0 */
z5 = d3 + d1;
tmp2 = MULTIPLY(d3, - FIX(1.451774981));
tmp3 = MULTIPLY(d1, (FIX(0.211164243) - 1));
z1 = MULTIPLY(d1, FIX(1.061594337));
z2 = MULTIPLY(d3, - FIX(2.172734803));
z4 = MULTIPLY(z5, FIX(0.785694958));
z5 = MULTIPLY(z5, FIX(1.175875602));
tmp0 = z1 - z4;
tmp1 = z2 + z4;
tmp2 += z5;
tmp3 += z5;
} else {
/* d1 == 0, d3 != 0, d5 == 0, d7 == 0 */
tmp0 = MULTIPLY(d3, - FIX2(0.785694958));
tmp1 = MULTIPLY(d3, - FIX2(1.387039845));
tmp2 = MULTIPLY(d3, - FIX2(0.275899379));
tmp3 = MULTIPLY(d3, FIX(1.175875602));
}
} else {
if (d1) {
/* d1 != 0, d3 == 0, d5 == 0, d7 == 0 */
tmp0 = MULTIPLY(d1, FIX2(0.275899379));
tmp1 = MULTIPLY(d1, FIX2(0.785694958));
tmp2 = MULTIPLY(d1, FIX(1.175875602));
tmp3 = MULTIPLY(d1, FIX2(1.387039845));
} else {
/* d1 == 0, d3 == 0, d5 == 0, d7 == 0 */
tmp0 = tmp1 = tmp2 = tmp3 = 0;
}
}
}
}
/* Final output stage: inputs are tmp10..tmp13, tmp0..tmp3 */
dataptr[0] = (DCTELEM) DESCALE(tmp10 + tmp3, CONST_BITS-PASS1_BITS);
dataptr[7] = (DCTELEM) DESCALE(tmp10 - tmp3, CONST_BITS-PASS1_BITS);
dataptr[1] = (DCTELEM) DESCALE(tmp11 + tmp2, CONST_BITS-PASS1_BITS);
dataptr[6] = (DCTELEM) DESCALE(tmp11 - tmp2, CONST_BITS-PASS1_BITS);
dataptr[2] = (DCTELEM) DESCALE(tmp12 + tmp1, CONST_BITS-PASS1_BITS);
dataptr[5] = (DCTELEM) DESCALE(tmp12 - tmp1, CONST_BITS-PASS1_BITS);
dataptr[3] = (DCTELEM) DESCALE(tmp13 + tmp0, CONST_BITS-PASS1_BITS);
dataptr[4] = (DCTELEM) DESCALE(tmp13 - tmp0, CONST_BITS-PASS1_BITS);
dataptr += DCTSIZE; /* advance pointer to next row */
}
/* Pass 2: process columns. */
/* Note that we must descale the results by a factor of 8 == 2**3, */
/* and also undo the PASS1_BITS scaling. */
dataptr = data;
for (rowctr = DCTSIZE-1; rowctr >= 0; rowctr--) {
/* Columns of zeroes can be exploited in the same way as we did with rows.
* However, the row calculation has created many nonzero AC terms, so the
* simplification applies less often (typically 5% to 10% of the time).
* On machines with very fast multiplication, it's possible that the
* test takes more time than it's worth. In that case this section
* may be commented out.
*/
d0 = dataptr[DCTSIZE*0];
d1 = dataptr[DCTSIZE*1];
d2 = dataptr[DCTSIZE*2];
d3 = dataptr[DCTSIZE*3];
d4 = dataptr[DCTSIZE*4];
d5 = dataptr[DCTSIZE*5];
d6 = dataptr[DCTSIZE*6];
d7 = dataptr[DCTSIZE*7];
/* Even part: reverse the even part of the forward DCT. */
/* The rotator is sqrt(2)*c(-6). */
if (d6) {
if (d4) {
if (d2) {
if (d0) {
/* d0 != 0, d2 != 0, d4 != 0, d6 != 0 */
z1 = MULTIPLY(d2 + d6, FIX(0.541196100));
tmp2 = z1 + MULTIPLY(d6, - FIX(1.847759065));
tmp3 = z1 + MULTIPLY(d2, FIX(0.765366865));
tmp0 = (d0 + d4) << CONST_BITS;
tmp1 = (d0 - d4) << CONST_BITS;
tmp10 = tmp0 + tmp3;
tmp13 = tmp0 - tmp3;
tmp11 = tmp1 + tmp2;
tmp12 = tmp1 - tmp2;
} else {
/* d0 == 0, d2 != 0, d4 != 0, d6 != 0 */
z1 = MULTIPLY(d2 + d6, FIX(0.541196100));
tmp2 = z1 + MULTIPLY(d6, - FIX(1.847759065));
tmp3 = z1 + MULTIPLY(d2, FIX(0.765366865));
tmp0 = d4 << CONST_BITS;
tmp10 = tmp0 + tmp3;
tmp13 = tmp0 - tmp3;
tmp11 = tmp2 - tmp0;
tmp12 = -(tmp0 + tmp2);
}
} else {
if (d0) {
/* d0 != 0, d2 == 0, d4 != 0, d6 != 0 */
tmp2 = MULTIPLY(d6, - FIX2(1.306562965));
tmp3 = MULTIPLY(d6, FIX(0.541196100));
tmp0 = (d0 + d4) << CONST_BITS;
tmp1 = (d0 - d4) << CONST_BITS;
tmp10 = tmp0 + tmp3;
tmp13 = tmp0 - tmp3;
tmp11 = tmp1 + tmp2;
tmp12 = tmp1 - tmp2;
} else {
/* d0 == 0, d2 == 0, d4 != 0, d6 != 0 */
tmp2 = MULTIPLY(d6, -FIX2(1.306562965));
tmp3 = MULTIPLY(d6, FIX(0.541196100));
tmp0 = d4 << CONST_BITS;
tmp10 = tmp0 + tmp3;
tmp13 = tmp0 - tmp3;
tmp11 = tmp2 - tmp0;
tmp12 = -(tmp0 + tmp2);
}
}
} else {
if (d2) {
if (d0) {
/* d0 != 0, d2 != 0, d4 == 0, d6 != 0 */
z1 = MULTIPLY(d2 + d6, FIX(0.541196100));
tmp2 = z1 + MULTIPLY(d6, - FIX(1.847759065));
tmp3 = z1 + MULTIPLY(d2, FIX(0.765366865));
tmp0 = d0 << CONST_BITS;
tmp10 = tmp0 + tmp3;
tmp13 = tmp0 - tmp3;
tmp11 = tmp0 + tmp2;
tmp12 = tmp0 - tmp2;
} else {
/* d0 == 0, d2 != 0, d4 == 0, d6 != 0 */
z1 = MULTIPLY(d2 + d6, FIX(0.541196100));
tmp2 = z1 + MULTIPLY(d6, - FIX(1.847759065));
tmp3 = z1 + MULTIPLY(d2, FIX(0.765366865));
tmp10 = tmp3;
tmp13 = -tmp3;
tmp11 = tmp2;
tmp12 = -tmp2;
}
} else {
if (d0) {
/* d0 != 0, d2 == 0, d4 == 0, d6 != 0 */
tmp2 = MULTIPLY(d6, - FIX2(1.306562965));
tmp3 = MULTIPLY(d6, FIX(0.541196100));
tmp0 = d0 << CONST_BITS;
tmp10 = tmp0 + tmp3;
tmp13 = tmp0 - tmp3;
tmp11 = tmp0 + tmp2;
tmp12 = tmp0 - tmp2;
} else {
/* d0 == 0, d2 == 0, d4 == 0, d6 != 0 */
tmp2 = MULTIPLY(d6, - FIX2(1.306562965));
tmp3 = MULTIPLY(d6, FIX(0.541196100));
tmp10 = tmp3;
tmp13 = -tmp3;
tmp11 = tmp2;
tmp12 = -tmp2;
}
}
}
} else {
if (d4) {
if (d2) {
if (d0) {
/* d0 != 0, d2 != 0, d4 != 0, d6 == 0 */
tmp2 = MULTIPLY(d2, FIX(0.541196100));
tmp3 = (INT32) (MULTIPLY(d2, (FIX(1.306562965) + .5)));
tmp0 = (d0 + d4) << CONST_BITS;
tmp1 = (d0 - d4) << CONST_BITS;
tmp10 = tmp0 + tmp3;
tmp13 = tmp0 - tmp3;
tmp11 = tmp1 + tmp2;
tmp12 = tmp1 - tmp2;
} else {
/* d0 == 0, d2 != 0, d4 != 0, d6 == 0 */
tmp2 = MULTIPLY(d2, FIX(0.541196100));
tmp3 = (INT32) (MULTIPLY(d2, (FIX(1.306562965) + .5)));
tmp0 = d4 << CONST_BITS;
tmp10 = tmp0 + tmp3;
tmp13 = tmp0 - tmp3;
tmp11 = tmp2 - tmp0;
tmp12 = -(tmp0 + tmp2);
}
} else {
if (d0) {
/* d0 != 0, d2 == 0, d4 != 0, d6 == 0 */
tmp10 = tmp13 = (d0 + d4) << CONST_BITS;
tmp11 = tmp12 = (d0 - d4) << CONST_BITS;
} else {
/* d0 == 0, d2 == 0, d4 != 0, d6 == 0 */
tmp10 = tmp13 = d4 << CONST_BITS;
tmp11 = tmp12 = -tmp10;
}
}
} else {
if (d2) {
if (d0) {
/* d0 != 0, d2 != 0, d4 == 0, d6 == 0 */
tmp2 = MULTIPLY(d2, FIX(0.541196100));
tmp3 = (INT32) (MULTIPLY(d2, (FIX(1.306562965) + .5)));
tmp0 = d0 << CONST_BITS;
tmp10 = tmp0 + tmp3;
tmp13 = tmp0 - tmp3;
tmp11 = tmp0 + tmp2;
tmp12 = tmp0 - tmp2;
} else {
/* d0 == 0, d2 != 0, d4 == 0, d6 == 0 */
tmp2 = MULTIPLY(d2, FIX(0.541196100));
tmp3 = (INT32) (MULTIPLY(d2, (FIX(1.306562965) + .5)));
tmp10 = tmp3;
tmp13 = -tmp3;
tmp11 = tmp2;
tmp12 = -tmp2;
}
} else {
if (d0) {
/* d0 != 0, d2 == 0, d4 == 0, d6 == 0 */
tmp10 = tmp13 = tmp11 = tmp12 = d0 << CONST_BITS;
} else {
/* d0 == 0, d2 == 0, d4 == 0, d6 == 0 */
tmp10 = tmp13 = tmp11 = tmp12 = 0;
}
}
}
}
/* Odd part per figure 8; the matrix is unitary and hence its
* transpose is its inverse. i0..i3 are y7,y5,y3,y1 respectively.
*/
if (d7) {
if (d5) {
if (d3) {
if (d1) {
/* d1 != 0, d3 != 0, d5 != 0, d7 != 0 */
z1 = d7 + d1;
z2 = d5 + d3;
z3 = d7 + d3;
z4 = d5 + d1;
z5 = MULTIPLY(z3 + z4, FIX(1.175875602));
tmp0 = MULTIPLY(d7, FIX(0.298631336));
tmp1 = MULTIPLY(d5, FIX(2.053119869));
tmp2 = MULTIPLY(d3, FIX(3.072711026));
tmp3 = MULTIPLY(d1, FIX(1.501321110));
z1 = MULTIPLY(z1, - FIX(0.899976223));
z2 = MULTIPLY(z2, - FIX(2.562915447));
z3 = MULTIPLY(z3, - FIX(1.961570560));
z4 = MULTIPLY(z4, - FIX(0.390180644));
z3 += z5;
z4 += z5;
tmp0 += z1 + z3;
tmp1 += z2 + z4;
tmp2 += z2 + z3;
tmp3 += z1 + z4;
} else {
/* d1 == 0, d3 != 0, d5 != 0, d7 != 0 */
z2 = d5 + d3;
z3 = d7 + d3;
z5 = MULTIPLY(z3 + d5, FIX(1.175875602));
tmp0 = MULTIPLY(d7, FIX(0.298631336));
tmp1 = MULTIPLY(d5, FIX(2.053119869));
tmp2 = MULTIPLY(d3, FIX(3.072711026));
z1 = MULTIPLY(d7, - FIX(0.899976223));
z2 = MULTIPLY(z2, - FIX(2.562915447));
z3 = MULTIPLY(z3, - FIX(1.961570560));
z4 = MULTIPLY(d5, - FIX(0.390180644));
z3 += z5;
z4 += z5;
tmp0 += z1 + z3;
tmp1 += z2 + z4;
tmp2 += z2 + z3;
tmp3 = z1 + z4;
}
} else {
if (d1) {
/* d1 != 0, d3 == 0, d5 != 0, d7 != 0 */
z1 = d7 + d1;
z4 = d5 + d1;
z5 = MULTIPLY(d7 + z4, FIX(1.175875602));
tmp0 = MULTIPLY(d7, FIX(0.298631336));
tmp1 = MULTIPLY(d5, FIX(2.053119869));
tmp3 = MULTIPLY(d1, FIX(1.501321110));
z1 = MULTIPLY(z1, - FIX(0.899976223));
z2 = MULTIPLY(d5, - FIX(2.562915447));
z3 = MULTIPLY(d7, - FIX(1.961570560));
z4 = MULTIPLY(z4, - FIX(0.390180644));
z3 += z5;
z4 += z5;
tmp0 += z1 + z3;
tmp1 += z2 + z4;
tmp2 = z2 + z3;
tmp3 += z1 + z4;
} else {
/* d1 == 0, d3 == 0, d5 != 0, d7 != 0 */
z5 = MULTIPLY(d5 + d7, FIX(1.175875602));
tmp0 = MULTIPLY(d7, - FIX2(0.601344887));
tmp1 = MULTIPLY(d5, - FIX2(0.509795578));
z1 = MULTIPLY(d7, - FIX(0.899976223));
z3 = MULTIPLY(d7, - FIX(1.961570560));
z2 = MULTIPLY(d5, - FIX(2.562915447));
z4 = MULTIPLY(d5, - FIX(0.390180644));
z3 += z5;
z4 += z5;
tmp0 += z3;
tmp1 += z4;
tmp2 = z2 + z3;
tmp3 = z1 + z4;
}
}
} else {
if (d3) {
if (d1) {
/* d1 != 0, d3 != 0, d5 == 0, d7 != 0 */
z1 = d7 + d1;
z3 = d7 + d3;
z5 = MULTIPLY(z3 + d1, FIX(1.175875602));
tmp0 = MULTIPLY(d7, FIX(0.298631336));
tmp2 = MULTIPLY(d3, FIX(3.072711026));
tmp3 = MULTIPLY(d1, FIX(1.501321110));
z1 = MULTIPLY(z1, - FIX(0.899976223));
z2 = MULTIPLY(d3, - FIX(2.562915447));
z3 = MULTIPLY(z3, - FIX(1.961570560));
z4 = MULTIPLY(d1, - FIX(0.390180644));
z3 += z5;
z4 += z5;
tmp0 += z1 + z3;
tmp1 = z2 + z4;
tmp2 += z2 + z3;
tmp3 += z1 + z4;
} else {
/* d1 == 0, d3 != 0, d5 == 0, d7 != 0 */
z3 = d7 + d3;
z5 = MULTIPLY(z3, FIX(1.175875602));
tmp0 = MULTIPLY(d7, - FIX2(0.601344887));
z1 = MULTIPLY(d7, - FIX(0.899976223));
tmp2 = MULTIPLY(d3, FIX(0.509795579));
z2 = MULTIPLY(d3, - FIX(2.562915447));
z3 = MULTIPLY(z3, - FIX2(0.785694958));
tmp0 += z3;
tmp1 = z2 + z5;
tmp2 += z3;
tmp3 = z1 + z5;
}
} else {
if (d1) {
/* d1 != 0, d3 == 0, d5 == 0, d7 != 0 */
z1 = d7 + d1;
z5 = MULTIPLY(z1, FIX(1.175875602));
tmp0 = MULTIPLY(d7, - FIX2(1.662939224));
tmp3 = MULTIPLY(d1, FIX2(1.111140466));
z1 = MULTIPLY(z1, FIX2(0.275899379));
z3 = MULTIPLY(d7, - FIX(1.961570560));
z4 = MULTIPLY(d1, - FIX(0.390180644));
tmp0 += z1;
tmp1 = z4 + z5;
tmp2 = z3 + z5;
tmp3 += z1;
} else {
/* d1 == 0, d3 == 0, d5 == 0, d7 != 0 */
tmp0 = MULTIPLY(d7, - FIX2(1.387039845));
tmp1 = MULTIPLY(d7, FIX(1.175875602));
tmp2 = MULTIPLY(d7, - FIX2(0.785694958));
tmp3 = MULTIPLY(d7, FIX2(0.275899379));
}
}
}
} else {
if (d5) {
if (d3) {
if (d1) {
/* d1 != 0, d3 != 0, d5 != 0, d7 == 0 */
z2 = d5 + d3;
z4 = d5 + d1;
z5 = MULTIPLY(d3 + z4, FIX(1.175875602));
tmp1 = MULTIPLY(d5, FIX(2.053119869));
tmp2 = MULTIPLY(d3, FIX(3.072711026));
tmp3 = MULTIPLY(d1, FIX(1.501321110));
z1 = MULTIPLY(d1, - FIX(0.899976223));
z2 = MULTIPLY(z2, - FIX(2.562915447));
z3 = MULTIPLY(d3, - FIX(1.961570560));
z4 = MULTIPLY(z4, - FIX(0.390180644));
z3 += z5;
z4 += z5;
tmp0 = z1 + z3;
tmp1 += z2 + z4;
tmp2 += z2 + z3;
tmp3 += z1 + z4;
} else {
/* d1 == 0, d3 != 0, d5 != 0, d7 == 0 */
z2 = d5 + d3;
z5 = MULTIPLY(z2, FIX(1.175875602));
tmp1 = MULTIPLY(d5, FIX2(1.662939225));
tmp2 = MULTIPLY(d3, FIX2(1.111140466));
z2 = MULTIPLY(z2, - FIX2(1.387039845));
z3 = MULTIPLY(d3, - FIX(1.961570560));
z4 = MULTIPLY(d5, - FIX(0.390180644));
tmp0 = z3 + z5;
tmp1 += z2;
tmp2 += z2;
tmp3 = z4 + z5;
}
} else {
if (d1) {
/* d1 != 0, d3 == 0, d5 != 0, d7 == 0 */
z4 = d5 + d1;
z5 = MULTIPLY(z4, FIX(1.175875602));
tmp1 = MULTIPLY(d5, - FIX2(0.509795578));
tmp3 = MULTIPLY(d1, FIX2(0.601344887));
z1 = MULTIPLY(d1, - FIX(0.899976223));
z2 = MULTIPLY(d5, - FIX(2.562915447));
z4 = MULTIPLY(z4, FIX2(0.785694958));
tmp0 = z1 + z5;
tmp1 += z4;
tmp2 = z2 + z5;
tmp3 += z4;
} else {
/* d1 == 0, d3 == 0, d5 != 0, d7 == 0 */
tmp0 = MULTIPLY(d5, FIX(1.175875602));
tmp1 = MULTIPLY(d5, FIX2(0.275899380));
tmp2 = MULTIPLY(d5, - FIX2(1.387039845));
tmp3 = MULTIPLY(d5, FIX2(0.785694958));
}
}
} else {
if (d3) {
if (d1) {
/* d1 != 0, d3 != 0, d5 == 0, d7 == 0 */
z5 = d3 + d1;
tmp2 = MULTIPLY(d3, - FIX(1.451774981));
tmp3 = MULTIPLY(d1, (FIX(0.211164243) - 1));
z1 = MULTIPLY(d1, FIX(1.061594337));
z2 = MULTIPLY(d3, - FIX(2.172734803));
z4 = MULTIPLY(z5, FIX(0.785694958));
z5 = MULTIPLY(z5, FIX(1.175875602));
tmp0 = z1 - z4;
tmp1 = z2 + z4;
tmp2 += z5;
tmp3 += z5;
} else {
/* d1 == 0, d3 != 0, d5 == 0, d7 == 0 */
tmp0 = MULTIPLY(d3, - FIX2(0.785694958));
tmp1 = MULTIPLY(d3, - FIX2(1.387039845));
tmp2 = MULTIPLY(d3, - FIX2(0.275899379));
tmp3 = MULTIPLY(d3, FIX(1.175875602));
}
} else {
if (d1) {
/* d1 != 0, d3 == 0, d5 == 0, d7 == 0 */
tmp0 = MULTIPLY(d1, FIX2(0.275899379));
tmp1 = MULTIPLY(d1, FIX2(0.785694958));
tmp2 = MULTIPLY(d1, FIX(1.175875602));
tmp3 = MULTIPLY(d1, FIX2(1.387039845));
} else {
/* d1 == 0, d3 == 0, d5 == 0, d7 == 0 */
tmp0 = tmp1 = tmp2 = tmp3 = 0;
}
}
}
}
/* Final output stage: inputs are tmp10..tmp13, tmp0..tmp3 */
dataptr[DCTSIZE*0] = (DCTELEM) DESCALE(tmp10 + tmp3,
CONST_BITS+PASS1_BITS+3);
dataptr[DCTSIZE*7] = (DCTELEM) DESCALE(tmp10 - tmp3,
CONST_BITS+PASS1_BITS+3);
dataptr[DCTSIZE*1] = (DCTELEM) DESCALE(tmp11 + tmp2,
CONST_BITS+PASS1_BITS+3);
dataptr[DCTSIZE*6] = (DCTELEM) DESCALE(tmp11 - tmp2,
CONST_BITS+PASS1_BITS+3);
dataptr[DCTSIZE*2] = (DCTELEM) DESCALE(tmp12 + tmp1,
CONST_BITS+PASS1_BITS+3);
dataptr[DCTSIZE*5] = (DCTELEM) DESCALE(tmp12 - tmp1,
CONST_BITS+PASS1_BITS+3);
dataptr[DCTSIZE*3] = (DCTELEM) DESCALE(tmp13 + tmp0,
CONST_BITS+PASS1_BITS+3);
dataptr[DCTSIZE*4] = (DCTELEM) DESCALE(tmp13 - tmp0,
CONST_BITS+PASS1_BITS+3);
dataptr++; /* advance pointer to next column */
}
}
#else
/*
*--------------------------------------------------------------
*
* j_rev_dct --
*
* The original inverse DCT function.
*
* Results:
* None.
*
* Side effects:
* None.
*
*--------------------------------------------------------------
*/
void j_rev_dct (DCTBLOCK data)
{
INT32 tmp0, tmp1, tmp2, tmp3;
INT32 tmp10, tmp11, tmp12, tmp13;
INT32 z1, z2, z3, z4, z5;
DCTELEM *dataptr;
int rowctr;
SHIFT_TEMPS
/* Pass 1: process rows. */
/* Note results are scaled up by sqrt(8) compared to a true IDCT; */
/* furthermore, we scale the results by 2**PASS1_BITS. */
dataptr = data;
for (rowctr = DCTSIZE-1; rowctr >= 0; rowctr--) {
/* Due to quantization, we will usually find that many of the input
* coefficients are zero, especially the AC terms. We can exploit this
* by short-circuiting the IDCT calculation for any row in which all
* the AC terms are zero. In that case each output is equal to the
* DC coefficient (with scale factor as needed).
* With typical images and quantization tables, half or more of the
* row DCT calculations can be simplified this way.
*/
if ((dataptr[1] | dataptr[2] | dataptr[3] | dataptr[4] |
dataptr[5] | dataptr[6] | dataptr[7]) == 0) {
/* AC terms all zero */
DCTELEM dcval = (DCTELEM) (dataptr[0] << PASS1_BITS);
dataptr[0] = dcval;
dataptr[1] = dcval;
dataptr[2] = dcval;
dataptr[3] = dcval;
dataptr[4] = dcval;
dataptr[5] = dcval;
dataptr[6] = dcval;
dataptr[7] = dcval;
dataptr += DCTSIZE; /* advance pointer to next row */
continue;
}
/* Even part: reverse the even part of the forward DCT. */
/* The rotator is sqrt(2)*c(-6). */
z2 = (INT32) dataptr[2];
z3 = (INT32) dataptr[6];
z1 = MULTIPLY(z2 + z3, FIX(0.541196100));
tmp2 = z1 + MULTIPLY(z3, - FIX(1.847759065));
tmp3 = z1 + MULTIPLY(z2, FIX(0.765366865));
tmp0 = ((INT32) dataptr[0] + (INT32) dataptr[4]) << CONST_BITS;
tmp1 = ((INT32) dataptr[0] - (INT32) dataptr[4]) << CONST_BITS;
tmp10 = tmp0 + tmp3;
tmp13 = tmp0 - tmp3;
tmp11 = tmp1 + tmp2;
tmp12 = tmp1 - tmp2;
/* Odd part per figure 8; the matrix is unitary and hence its
* transpose is its inverse. i0..i3 are y7,y5,y3,y1 respectively.
*/
tmp0 = (INT32) dataptr[7];
tmp1 = (INT32) dataptr[5];
tmp2 = (INT32) dataptr[3];
tmp3 = (INT32) dataptr[1];
z1 = tmp0 + tmp3;
z2 = tmp1 + tmp2;
z3 = tmp0 + tmp2;
z4 = tmp1 + tmp3;
z5 = MULTIPLY(z3 + z4, FIX(1.175875602)); /* sqrt(2) * c3 */
tmp0 = MULTIPLY(tmp0, FIX(0.298631336)); /* sqrt(2) * (-c1+c3+c5-c7) */
tmp1 = MULTIPLY(tmp1, FIX(2.053119869)); /* sqrt(2) * ( c1+c3-c5+c7) */
tmp2 = MULTIPLY(tmp2, FIX(3.072711026)); /* sqrt(2) * ( c1+c3+c5-c7) */
tmp3 = MULTIPLY(tmp3, FIX(1.501321110)); /* sqrt(2) * ( c1+c3-c5-c7) */
z1 = MULTIPLY(z1, - FIX(0.899976223)); /* sqrt(2) * (c7-c3) */
z2 = MULTIPLY(z2, - FIX(2.562915447)); /* sqrt(2) * (-c1-c3) */
z3 = MULTIPLY(z3, - FIX(1.961570560)); /* sqrt(2) * (-c3-c5) */
z4 = MULTIPLY(z4, - FIX(0.390180644)); /* sqrt(2) * (c5-c3) */
z3 += z5;
z4 += z5;
tmp0 += z1 + z3;
tmp1 += z2 + z4;
tmp2 += z2 + z3;
tmp3 += z1 + z4;
/* Final output stage: inputs are tmp10..tmp13, tmp0..tmp3 */
dataptr[0] = (DCTELEM) DESCALE(tmp10 + tmp3, CONST_BITS-PASS1_BITS);
dataptr[7] = (DCTELEM) DESCALE(tmp10 - tmp3, CONST_BITS-PASS1_BITS);
dataptr[1] = (DCTELEM) DESCALE(tmp11 + tmp2, CONST_BITS-PASS1_BITS);
dataptr[6] = (DCTELEM) DESCALE(tmp11 - tmp2, CONST_BITS-PASS1_BITS);
dataptr[2] = (DCTELEM) DESCALE(tmp12 + tmp1, CONST_BITS-PASS1_BITS);
dataptr[5] = (DCTELEM) DESCALE(tmp12 - tmp1, CONST_BITS-PASS1_BITS);
dataptr[3] = (DCTELEM) DESCALE(tmp13 + tmp0, CONST_BITS-PASS1_BITS);
dataptr[4] = (DCTELEM) DESCALE(tmp13 - tmp0, CONST_BITS-PASS1_BITS);
dataptr += DCTSIZE; /* advance pointer to next row */
}
/* Pass 2: process columns. */
/* Note that we must descale the results by a factor of 8 == 2**3, */
/* and also undo the PASS1_BITS scaling. */
dataptr = data;
for (rowctr = DCTSIZE-1; rowctr >= 0; rowctr--) {
/* Columns of zeroes can be exploited in the same way as we did with rows.
* However, the row calculation has created many nonzero AC terms, so the
* simplification applies less often (typically 5% to 10% of the time).
* On machines with very fast multiplication, it's possible that the
* test takes more time than it's worth. In that case this section
* may be commented out.
*/
#ifndef NO_ZERO_COLUMN_TEST
if ((dataptr[DCTSIZE*1] | dataptr[DCTSIZE*2] | dataptr[DCTSIZE*3] |
dataptr[DCTSIZE*4] | dataptr[DCTSIZE*5] | dataptr[DCTSIZE*6] |
dataptr[DCTSIZE*7]) == 0) {
/* AC terms all zero */
DCTELEM dcval = (DCTELEM) DESCALE((INT32) dataptr[0], PASS1_BITS+3);
dataptr[DCTSIZE*0] = dcval;
dataptr[DCTSIZE*1] = dcval;
dataptr[DCTSIZE*2] = dcval;
dataptr[DCTSIZE*3] = dcval;
dataptr[DCTSIZE*4] = dcval;
dataptr[DCTSIZE*5] = dcval;
dataptr[DCTSIZE*6] = dcval;
dataptr[DCTSIZE*7] = dcval;
dataptr++; /* advance pointer to next column */
continue;
}
#endif
/* Even part: reverse the even part of the forward DCT. */
/* The rotator is sqrt(2)*c(-6). */
z2 = (INT32) dataptr[DCTSIZE*2];
z3 = (INT32) dataptr[DCTSIZE*6];
z1 = MULTIPLY(z2 + z3, FIX(0.541196100));
tmp2 = z1 + MULTIPLY(z3, - FIX(1.847759065));
tmp3 = z1 + MULTIPLY(z2, FIX(0.765366865));
tmp0 = ((INT32) dataptr[DCTSIZE*0] + (INT32) dataptr[DCTSIZE*4]) << CONST_BITS;
tmp1 = ((INT32) dataptr[DCTSIZE*0] - (INT32) dataptr[DCTSIZE*4]) << CONST_BITS;
tmp10 = tmp0 + tmp3;
tmp13 = tmp0 - tmp3;
tmp11 = tmp1 + tmp2;
tmp12 = tmp1 - tmp2;
/* Odd part per figure 8; the matrix is unitary and hence its
* transpose is its inverse. i0..i3 are y7,y5,y3,y1 respectively.
*/
tmp0 = (INT32) dataptr[DCTSIZE*7];
tmp1 = (INT32) dataptr[DCTSIZE*5];
tmp2 = (INT32) dataptr[DCTSIZE*3];
tmp3 = (INT32) dataptr[DCTSIZE*1];
z1 = tmp0 + tmp3;
z2 = tmp1 + tmp2;
z3 = tmp0 + tmp2;
z4 = tmp1 + tmp3;
z5 = MULTIPLY(z3 + z4, FIX(1.175875602)); /* sqrt(2) * c3 */
tmp0 = MULTIPLY(tmp0, FIX(0.298631336)); /* sqrt(2) * (-c1+c3+c5-c7) */
tmp1 = MULTIPLY(tmp1, FIX(2.053119869)); /* sqrt(2) * ( c1+c3-c5+c7) */
tmp2 = MULTIPLY(tmp2, FIX(3.072711026)); /* sqrt(2) * ( c1+c3+c5-c7) */
tmp3 = MULTIPLY(tmp3, FIX(1.501321110)); /* sqrt(2) * ( c1+c3-c5-c7) */
z1 = MULTIPLY(z1, - FIX(0.899976223)); /* sqrt(2) * (c7-c3) */
z2 = MULTIPLY(z2, - FIX(2.562915447)); /* sqrt(2) * (-c1-c3) */
z3 = MULTIPLY(z3, - FIX(1.961570560)); /* sqrt(2) * (-c3-c5) */
z4 = MULTIPLY(z4, - FIX(0.390180644)); /* sqrt(2) * (c5-c3) */
z3 += z5;
z4 += z5;
tmp0 += z1 + z3;
tmp1 += z2 + z4;
tmp2 += z2 + z3;
tmp3 += z1 + z4;
/* Final output stage: inputs are tmp10..tmp13, tmp0..tmp3 */
dataptr[DCTSIZE*0] = (DCTELEM) DESCALE(tmp10 + tmp3,
CONST_BITS+PASS1_BITS+3);
dataptr[DCTSIZE*7] = (DCTELEM) DESCALE(tmp10 - tmp3,
CONST_BITS+PASS1_BITS+3);
dataptr[DCTSIZE*1] = (DCTELEM) DESCALE(tmp11 + tmp2,
CONST_BITS+PASS1_BITS+3);
dataptr[DCTSIZE*6] = (DCTELEM) DESCALE(tmp11 - tmp2,
CONST_BITS+PASS1_BITS+3);
dataptr[DCTSIZE*2] = (DCTELEM) DESCALE(tmp12 + tmp1,
CONST_BITS+PASS1_BITS+3);
dataptr[DCTSIZE*5] = (DCTELEM) DESCALE(tmp12 - tmp1,
CONST_BITS+PASS1_BITS+3);
dataptr[DCTSIZE*3] = (DCTELEM) DESCALE(tmp13 + tmp0,
CONST_BITS+PASS1_BITS+3);
dataptr[DCTSIZE*4] = (DCTELEM) DESCALE(tmp13 - tmp0,
CONST_BITS+PASS1_BITS+3);
dataptr++; /* advance pointer to next column */
}
}
#endif /* ORIG_DCT */
#endif /* FIVE_DCT */
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