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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;
+ register int *dp;
+ register 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;
+ register 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.
+ */
+
+ register 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);
+ register 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;
+ register 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 */
+