/src/FreeImage/Source/LibJPEG/jidctint.c
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- /*
- * jidctint.c
- *
- * Copyright (C) 1991-1998, Thomas G. Lane.
- * Modification developed 2002-2009 by Guido Vollbeding.
- * 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 a slow-but-accurate integer implementation of the
- * inverse DCT (Discrete Cosine Transform). In the IJG code, this routine
- * must also perform dequantization of the input coefficients.
- *
- * A 2-D IDCT can be done by 1-D IDCT on each column followed by 1-D IDCT
- * on each row (or vice versa, but it's more convenient to emit a row at
- * a time). Direct algorithms are also available, but they are much more
- * complex and seem not to be any faster when reduced to code.
- *
- * 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.
- *
- * We also provide IDCT routines with various output sample block sizes for
- * direct resolution reduction or enlargement and for direct resolving the
- * common 2x1 and 1x2 subsampling cases without additional resampling: NxN
- * (N=1...16), 2NxN, and Nx2N (N=1...8) pixels for one 8x8 input DCT block.
- *
- * For N<8 we simply take the corresponding low-frequency coefficients of
- * the 8x8 input DCT block and apply an NxN point IDCT on the sub-block
- * to yield the downscaled outputs.
- * This can be seen as direct low-pass downsampling from the DCT domain
- * point of view rather than the usual spatial domain point of view,
- * yielding significant computational savings and results at least
- * as good as common bilinear (averaging) spatial downsampling.
- *
- * For N>8 we apply a partial NxN IDCT on the 8 input coefficients as
- * lower frequencies and higher frequencies assumed to be zero.
- * It turns out that the computational effort is similar to the 8x8 IDCT
- * regarding the output size.
- * Furthermore, the scaling and descaling is the same for all IDCT sizes.
- *
- * CAUTION: We rely on the FIX() macro except for the N=1,2,4,8 cases
- * since there would be too many additional constants to pre-calculate.
- */
- #define JPEG_INTERNALS
- #include "jinclude.h"
- #include "jpeglib.h"
- #include "jdct.h" /* Private declarations for DCT subsystem */
- #ifdef DCT_ISLOW_SUPPORTED
- /*
- * This module is specialized to the case DCTSIZE = 8.
- */
- #if DCTSIZE != 8
- Sorry, this code only copes with 8x8 DCT blocks. /* deliberate syntax err */
- #endif
- /*
- * 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.
- */
- #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_298631336 ((INT32) 2446) /* FIX(0.298631336) */
- #define FIX_0_390180644 ((INT32) 3196) /* FIX(0.390180644) */
- #define FIX_0_541196100 ((INT32) 4433) /* FIX(0.541196100) */
- #define FIX_0_765366865 ((INT32) 6270) /* FIX(0.765366865) */
- #define FIX_0_899976223 ((INT32) 7373) /* FIX(0.899976223) */
- #define FIX_1_175875602 ((INT32) 9633) /* FIX(1.175875602) */
- #define FIX_1_501321110 ((INT32) 12299) /* FIX(1.501321110) */
- #define FIX_1_847759065 ((INT32) 15137) /* FIX(1.847759065) */
- #define FIX_1_961570560 ((INT32) 16069) /* FIX(1.961570560) */
- #define FIX_2_053119869 ((INT32) 16819) /* FIX(2.053119869) */
- #define FIX_2_562915447 ((INT32) 20995) /* FIX(2.562915447) */
- #define FIX_3_072711026 ((INT32) 25172) /* FIX(3.072711026) */
- #else
- #define FIX_0_298631336 FIX(0.298631336)
- #define FIX_0_390180644 FIX(0.390180644)
- #define FIX_0_541196100 FIX(0.541196100)
- #define FIX_0_765366865 FIX(0.765366865)
- #define FIX_0_899976223 FIX(0.899976223)
- #define FIX_1_175875602 FIX(1.175875602)
- #define FIX_1_501321110 FIX(1.501321110)
- #define FIX_1_847759065 FIX(1.847759065)
- #define FIX_1_961570560 FIX(1.961570560)
- #define FIX_2_053119869 FIX(2.053119869)
- #define FIX_2_562915447 FIX(2.562915447)
- #define FIX_3_072711026 FIX(3.072711026)
- #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.
- */
- GLOBAL(void)
- jpeg_idct_islow (j_decompress_ptr cinfo, jpeg_component_info * compptr,
- JCOEFPTR coef_block,
- JSAMPARRAY output_buf, JDIMENSION output_col)
- {
- INT32 tmp0, tmp1, tmp2, tmp3;
- INT32 tmp10, tmp11, tmp12, tmp13;
- INT32 z1, z2, z3;
- JCOEFPTR inptr;
- ISLOW_MULT_TYPE * quantptr;
- int * wsptr;
- JSAMPROW outptr;
- JSAMPLE *range_limit = IDCT_range_limit(cinfo);
- int ctr;
- int workspace[DCTSIZE2]; /* buffers data between passes */
- SHIFT_TEMPS
- /* Pass 1: process columns from input, store into work array. */
- /* Note results are scaled up by sqrt(8) compared to a true IDCT; */
- /* furthermore, we scale the results by 2**PASS1_BITS. */
- inptr = coef_block;
- quantptr = (ISLOW_MULT_TYPE *) compptr->dct_table;
- wsptr = workspace;
- for (ctr = DCTSIZE; ctr > 0; ctr--) {
- /* 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 column 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
- * column DCT calculations can be simplified this way.
- */
- if (inptr[DCTSIZE*1] == 0 && inptr[DCTSIZE*2] == 0 &&
- inptr[DCTSIZE*3] == 0 && inptr[DCTSIZE*4] == 0 &&
- inptr[DCTSIZE*5] == 0 && inptr[DCTSIZE*6] == 0 &&
- inptr[DCTSIZE*7] == 0) {
- /* AC terms all zero */
- 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;
- wsptr[DCTSIZE*4] = dcval;
- wsptr[DCTSIZE*5] = dcval;
- wsptr[DCTSIZE*6] = dcval;
- wsptr[DCTSIZE*7] = dcval;
- inptr++; /* advance pointers to next column */
- quantptr++;
- wsptr++;
- continue;
- }
- /* Even part: reverse the even part of the forward DCT. */
- /* The rotator is sqrt(2)*c(-6). */
-
- z2 = DEQUANTIZE(inptr[DCTSIZE*2], quantptr[DCTSIZE*2]);
- z3 = DEQUANTIZE(inptr[DCTSIZE*6], quantptr[DCTSIZE*6]);
- z1 = MULTIPLY(z2 + z3, FIX_0_541196100);
- tmp2 = z1 + MULTIPLY(z2, FIX_0_765366865);
- tmp3 = z1 - MULTIPLY(z3, FIX_1_847759065);
- z2 = DEQUANTIZE(inptr[DCTSIZE*0], quantptr[DCTSIZE*0]);
- z3 = DEQUANTIZE(inptr[DCTSIZE*4], quantptr[DCTSIZE*4]);
- z2 <<= CONST_BITS;
- z3 <<= CONST_BITS;
- /* Add fudge factor here for final descale. */
- z2 += ONE << (CONST_BITS-PASS1_BITS-1);
- tmp0 = z2 + z3;
- tmp1 = z2 - z3;
- tmp10 = tmp0 + tmp2;
- tmp13 = tmp0 - tmp2;
- tmp11 = tmp1 + tmp3;
- tmp12 = tmp1 - tmp3;
- /* 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 = DEQUANTIZE(inptr[DCTSIZE*7], quantptr[DCTSIZE*7]);
- tmp1 = DEQUANTIZE(inptr[DCTSIZE*5], quantptr[DCTSIZE*5]);
- tmp2 = DEQUANTIZE(inptr[DCTSIZE*3], quantptr[DCTSIZE*3]);
- tmp3 = DEQUANTIZE(inptr[DCTSIZE*1], quantptr[DCTSIZE*1]);
-
- z2 = tmp0 + tmp2;
- z3 = tmp1 + tmp3;
- z1 = MULTIPLY(z2 + z3, FIX_1_175875602); /* sqrt(2) * c3 */
- z2 = MULTIPLY(z2, - FIX_1_961570560); /* sqrt(2) * (-c3-c5) */
- z3 = MULTIPLY(z3, - FIX_0_390180644); /* sqrt(2) * (c5-c3) */
- z2 += z1;
- z3 += z1;
- z1 = MULTIPLY(tmp0 + tmp3, - FIX_0_899976223); /* sqrt(2) * (c7-c3) */
- tmp0 = MULTIPLY(tmp0, FIX_0_298631336); /* sqrt(2) * (-c1+c3+c5-c7) */
- tmp3 = MULTIPLY(tmp3, FIX_1_501321110); /* sqrt(2) * ( c1+c3-c5-c7) */
- tmp0 += z1 + z2;
- tmp3 += z1 + z3;
- z1 = MULTIPLY(tmp1 + tmp2, - FIX_2_562915447); /* sqrt(2) * (-c1-c3) */
- tmp1 = MULTIPLY(tmp1, FIX_2_053119869); /* sqrt(2) * ( c1+c3-c5+c7) */
- tmp2 = MULTIPLY(tmp2, FIX_3_072711026); /* sqrt(2) * ( c1+c3+c5-c7) */
- tmp1 += z1 + z3;
- tmp2 += z1 + z2;
- /* Final output stage: inputs are tmp10..tmp13, tmp0..tmp3 */
- wsptr[DCTSIZE*0] = (int) RIGHT_SHIFT(tmp10 + tmp3, CONST_BITS-PASS1_BITS);
- wsptr[DCTSIZE*7] = (int) RIGHT_SHIFT(tmp10 - tmp3, CONST_BITS-PASS1_BITS);
- wsptr[DCTSIZE*1] = (int) RIGHT_SHIFT(tmp11 + tmp2, CONST_BITS-PASS1_BITS);
- wsptr[DCTSIZE*6] = (int) RIGHT_SHIFT(tmp11 - tmp2, CONST_BITS-PASS1_BITS);
- wsptr[DCTSIZE*2] = (int) RIGHT_SHIFT(tmp12 + tmp1, CONST_BITS-PASS1_BITS);
- wsptr[DCTSIZE*5] = (int) RIGHT_SHIFT(tmp12 - tmp1, CONST_BITS-PASS1_BITS);
- wsptr[DCTSIZE*3] = (int) RIGHT_SHIFT(tmp13 + tmp0, CONST_BITS-PASS1_BITS);
- wsptr[DCTSIZE*4] = (int) RIGHT_SHIFT(tmp13 - tmp0, CONST_BITS-PASS1_BITS);
-
- inptr++; /* advance pointers to next column */
- quantptr++;
- wsptr++;
- }
- /* Pass 2: process rows from work array, store into output array. */
- /* Note that we must descale the results by a factor of 8 == 2**3, */
- /* and also undo the PASS1_BITS scaling. */
- wsptr = workspace;
- for (ctr = 0; ctr < DCTSIZE; ctr++) {
- outptr = output_buf[ctr] + output_col;
- /* Rows of zeroes can be exploited in the same way as we did with columns.
- * However, the column 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_ROW_TEST
- if (wsptr[1] == 0 && wsptr[2] == 0 && wsptr[3] == 0 && wsptr[4] == 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;
- outptr[4] = dcval;
- outptr[5] = dcval;
- outptr[6] = dcval;
- outptr[7] = dcval;
- wsptr += DCTSIZE; /* advance pointer to next row */
- continue;
- }
- #endif
- /* Even part: reverse the even part of the forward DCT. */
- /* The rotator is sqrt(2)*c(-6). */
-
- z2 = (INT32) wsptr[2];
- z3 = (INT32) wsptr[6];
- z1 = MULTIPLY(z2 + z3, FIX_0_541196100);
- tmp2 = z1 + MULTIPLY(z2, FIX_0_765366865);
- tmp3 = z1 - MULTIPLY(z3, FIX_1_847759065);
- /* Add fudge factor here for final descale. */
- z2 = (INT32) wsptr[0] + (ONE << (PASS1_BITS+2));
- z3 = (INT32) wsptr[4];
- tmp0 = (z2 + z3) << CONST_BITS;
- tmp1 = (z2 - z3) << CONST_BITS;
-
- tmp10 = tmp0 + tmp2;
- tmp13 = tmp0 - tmp2;
- tmp11 = tmp1 + tmp3;
- tmp12 = tmp1 - tmp3;
- /* 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) wsptr[7];
- tmp1 = (INT32) wsptr[5];
- tmp2 = (INT32) wsptr[3];
- tmp3 = (INT32) wsptr[1];
- z2 = tmp0 + tmp2;
- z3 = tmp1 + tmp3;
- z1 = MULTIPLY(z2 + z3, FIX_1_175875602); /* sqrt(2) * c3 */
- z2 = MULTIPLY(z2, - FIX_1_961570560); /* sqrt(2) * (-c3-c5) */
- z3 = MULTIPLY(z3, - FIX_0_390180644); /* sqrt(2) * (c5-c3) */
- z2 += z1;
- z3 += z1;
- z1 = MULTIPLY(tmp0 + tmp3, - FIX_0_899976223); /* sqrt(2) * (c7-c3) */
- tmp0 = MULTIPLY(tmp0, FIX_0_298631336); /* sqrt(2) * (-c1+c3+c5-c7) */
- tmp3 = MULTIPLY(tmp3, FIX_1_501321110); /* sqrt(2) * ( c1+c3-c5-c7) */
- tmp0 += z1 + z2;
- tmp3 += z1 + z3;
- z1 = MULTIPLY(tmp1 + tmp2, - FIX_2_562915447); /* sqrt(2) * (-c1-c3) */
- tmp1 = MULTIPLY(tmp1, FIX_2_053119869); /* sqrt(2) * ( c1+c3-c5+c7) */
- tmp2 = MULTIPLY(tmp2, FIX_3_072711026); /* sqrt(2) * ( c1+c3+c5-c7) */
- tmp1 += z1 + z3;
- tmp2 += z1 + z2;
- /* Final output stage: inputs are tmp10..tmp13, tmp0..tmp3 */
- outptr[0] = range_limit[(int) RIGHT_SHIFT(tmp10 + tmp3,
- CONST_BITS+PASS1_BITS+3)
- & RANGE_MASK];
- outptr[7] = range_limit[(int) RIGHT_SHIFT(tmp10 - tmp3,
- CONST_BITS+PASS1_BITS+3)
- & RANGE_MASK];
- outptr[1] = range_limit[(int) RIGHT_SHIFT(tmp11 + tmp2,
- CONST_BITS+PASS1_BITS+3)
- & RANGE_MASK];
- outptr[6] = range_limit[(int) RIGHT_SHIFT(tmp11 - tmp2,
- CONST_BITS+PASS1_BITS+3)
- & RANGE_MASK];
- outptr[2] = range_limit[(int) RIGHT_SHIFT(tmp12 + tmp1,
- CONST_BITS+PASS1_BITS+3)
- & RANGE_MASK];
- outptr[5] = range_limit[(int) RIGHT_SHIFT(tmp12 - tmp1,
- CONST_BITS+PASS1_BITS+3)
- & RANGE_MASK];
- outptr[3] = range_limit[(int) RIGHT_SHIFT(tmp13 + tmp0,
- CONST_BITS+PASS1_BITS+3)
- & RANGE_MASK];
- outptr[4] = range_limit[(int) RIGHT_SHIFT(tmp13 - tmp0,
- CONST_BITS+PASS1_BITS+3)
- & RANGE_MASK];
- wsptr += DCTSIZE; /* advance pointer to next row */
- }
- }
- #ifdef IDCT_SCALING_SUPPORTED
- /*
- * Perform dequantization and inverse DCT on one block of coefficients,
- * producing a 7x7 output block.
- *
- * Optimized algorithm with 12 multiplications in the 1-D kernel.
- * cK represents sqrt(2) * cos(K*pi/14).
- */
- GLOBAL(void)
- jpeg_idct_7x7 (j_decompress_ptr cinfo, jpeg_component_info * compptr,
- JCOEFPTR coef_block,
- JSAMPARRAY output_buf, JDIMENSION output_col)
- {
- INT32 tmp0, tmp1, tmp2, tmp10, tmp11, tmp12, tmp13;
- INT32 z1, z2, z3;
- JCOEFPTR inptr;
- ISLOW_MULT_TYPE * quantptr;
- int * wsptr;
- JSAMPROW outptr;
- JSAMPLE *range_limit = IDCT_range_limit(cinfo);
- int ctr;
- int workspace[7*7]; /* 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 = 0; ctr < 7; ctr++, inptr++, quantptr++, wsptr++) {
- /* Even part */
- tmp13 = DEQUANTIZE(inptr[DCTSIZE*0], quantptr[DCTSIZE*0]);
- tmp13 <<= CONST_BITS;
- /* Add fudge factor here for final descale. */
- tmp13 += ONE << (CONST_BITS-PASS1_BITS-1);
- z1 = DEQUANTIZE(inptr[DCTSIZE*2], quantptr[DCTSIZE*2]);
- z2 = DEQUANTIZE(inptr[DCTSIZE*4], quantptr[DCTSIZE*4]);
- z3 = DEQUANTIZE(inptr[DCTSIZE*6], quantptr[DCTSIZE*6]);
- tmp10 = MULTIPLY(z2 - z3, FIX(0.881747734)); /* c4 */
- tmp12 = MULTIPLY(z1 - z2, FIX(0.314692123)); /* c6 */
- tmp11 = tmp10 + tmp12 + tmp13 - MULTIPLY(z2, FIX(1.841218003)); /* c2+c4-c6 */
- tmp0 = z1 + z3;
- z2 -= tmp0;
- tmp0 = MULTIPLY(tmp0, FIX(1.274162392)) + tmp13; /* c2 */
- tmp10 += tmp0 - MULTIPLY(z3, FIX(0.077722536)); /* c2-c4-c6 */
- tmp12 += tmp0 - MULTIPLY(z1, FIX(2.470602249)); /* c2+c4+c6 */
- tmp13 += MULTIPLY(z2, FIX(1.414213562)); /* c0 */
- /* Odd part */
- z1 = DEQUANTIZE(inptr[DCTSIZE*1], quantptr[DCTSIZE*1]);
- z2 = DEQUANTIZE(inptr[DCTSIZE*3], quantptr[DCTSIZE*3]);
- z3 = DEQUANTIZE(inptr[DCTSIZE*5], quantptr[DCTSIZE*5]);
- tmp1 = MULTIPLY(z1 + z2, FIX(0.935414347)); /* (c3+c1-c5)/2 */
- tmp2 = MULTIPLY(z1 - z2, FIX(0.170262339)); /* (c3+c5-c1)/2 */
- tmp0 = tmp1 - tmp2;
- tmp1 += tmp2;
- tmp2 = MULTIPLY(z2 + z3, - FIX(1.378756276)); /* -c1 */
- tmp1 += tmp2;
- z2 = MULTIPLY(z1 + z3, FIX(0.613604268)); /* c5 */
- tmp0 += z2;
- tmp2 += z2 + MULTIPLY(z3, FIX(1.870828693)); /* c3+c1-c5 */
- /* Final output stage */
- wsptr[7*0] = (int) RIGHT_SHIFT(tmp10 + tmp0, CONST_BITS-PASS1_BITS);
- wsptr[7*6] = (int) RIGHT_SHIFT(tmp10 - tmp0, CONST_BITS-PASS1_BITS);
- wsptr[7*1] = (int) RIGHT_SHIFT(tmp11 + tmp1, CONST_BITS-PASS1_BITS);
- wsptr[7*5] = (int) RIGHT_SHIFT(tmp11 - tmp1, CONST_BITS-PASS1_BITS);
- wsptr[7*2] = (int) RIGHT_SHIFT(tmp12 + tmp2, CONST_BITS-PASS1_BITS);
- wsptr[7*4] = (int) RIGHT_SHIFT(tmp12 - tmp2, CONST_BITS-PASS1_BITS);
- wsptr[7*3] = (int) RIGHT_SHIFT(tmp13, CONST_BITS-PASS1_BITS);
- }
- /* Pass 2: process 7 rows from work array, store into output array. */
- wsptr = workspace;
- for (ctr = 0; ctr < 7; ctr++) {
- outptr = output_buf[ctr] + output_col;
- /* Even part */
- /* Add fudge factor here for final descale. */
- tmp13 = (INT32) wsptr[0] + (ONE << (PASS1_BITS+2));
- tmp13 <<= CONST_BITS;
- z1 = (INT32) wsptr[2];
- z2 = (INT32) wsptr[4];
- z3 = (INT32) wsptr[6];
- tmp10 = MULTIPLY(z2 - z3, FIX(0.881747734)); /* c4 */
- tmp12 = MULTIPLY(z1 - z2, FIX(0.314692123)); /* c6 */
- tmp11 = tmp10 + tmp12 + tmp13 - MULTIPLY(z2, FIX(1.841218003)); /* c2+c4-c6 */
- tmp0 = z1 + z3;
- z2 -= tmp0;
- tmp0 = MULTIPLY(tmp0, FIX(1.274162392)) + tmp13; /* c2 */
- tmp10 += tmp0 - MULTIPLY(z3, FIX(0.077722536)); /* c2-c4-c6 */
- tmp12 += tmp0 - MULTIPLY(z1, FIX(2.470602249)); /* c2+c4+c6 */
- tmp13 += MULTIPLY(z2, FIX(1.414213562)); /* c0 */
- /* Odd part */
- z1 = (INT32) wsptr[1];
- z2 = (INT32) wsptr[3];
- z3 = (INT32) wsptr[5];
- tmp1 = MULTIPLY(z1 + z2, FIX(0.935414347)); /* (c3+c1-c5)/2 */
- tmp2 = MULTIPLY(z1 - z2, FIX(0.170262339)); /* (c3+c5-c1)/2 */
- tmp0 = tmp1 - tmp2;
- tmp1 += tmp2;
- tmp2 = MULTIPLY(z2 + z3, - FIX(1.378756276)); /* -c1 */
- tmp1 += tmp2;
- z2 = MULTIPLY(z1 + z3, FIX(0.613604268)); /* c5 */
- tmp0 += z2;
- tmp2 += z2 + MULTIPLY(z3, FIX(1.870828693)); /* c3+c1-c5 */
- /* Final output stage */
- outptr[0] = range_limit[(int) RIGHT_SHIFT(tmp10 + tmp0,
- CONST_BITS+PASS1_BITS+3)
- & RANGE_MASK];
- outptr[6] = range_limit[(int) RIGHT_SHIFT(tmp10 - tmp0,
- CONST_BITS+PASS1_BITS+3)
- & RANGE_MASK];
- outptr[1] = range_limit[(int) RIGHT_SHIFT(tmp11 + tmp1,
- CONST_BITS+PASS1_BITS+3)
- & RANGE_MASK];
- outptr[5] = range_limit[(int) RIGHT_SHIFT(tmp11 - tmp1,
- CONST_BITS+PASS1_BITS+3)
- & RANGE_MASK];
- outptr[2] = range_limit[(int) RIGHT_SHIFT(tmp12 + tmp2,
- CONST_BITS+PASS1_BITS+3)
- & RANGE_MASK];
- outptr[4] = range_limit[(int) RIGHT_SHIFT(tmp12 - tmp2,
- CONST_BITS+PASS1_BITS+3)
- & RANGE_MASK];
- outptr[3] = range_limit[(int) RIGHT_SHIFT(tmp13,
- CONST_BITS+PASS1_BITS+3)
- & RANGE_MASK];
- wsptr += 7; /* advance pointer to next row */
- }
- }
- /*
- * Perform dequantization and inverse DCT on one block of coefficients,
- * producing a reduced-size 6x6 output block.
- *
- * Optimized algorithm with 3 multiplications in the 1-D kernel.
- * cK represents sqrt(2) * cos(K*pi/12).
- */
- GLOBAL(void)
- jpeg_idct_6x6 (j_decompress_ptr cinfo, jpeg_component_info * compptr,
- JCOEFPTR coef_block,
- JSAMPARRAY output_buf, JDIMENSION output_col)
- {
- INT32 tmp0, tmp1, tmp2, tmp10, tmp11, tmp12;
- INT32 z1, z2, z3;
- JCOEFPTR inptr;
- ISLOW_MULT_TYPE * quantptr;
- int * wsptr;
- JSAMPROW outptr;
- JSAMPLE *range_limit = IDCT_range_limit(cinfo);
- int ctr;
- int workspace[6*6]; /* 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 = 0; ctr < 6; ctr++, inptr++, quantptr++, wsptr++) {
- /* Even part */
- tmp0 = DEQUANTIZE(inptr[DCTSIZE*0], quantptr[DCTSIZE*0]);
- tmp0 <<= CONST_BITS;
- /* Add fudge factor here for final descale. */
- tmp0 += ONE << (CONST_BITS-PASS1_BITS-1);
- tmp2 = DEQUANTIZE(inptr[DCTSIZE*4], quantptr[DCTSIZE*4]);
- tmp10 = MULTIPLY(tmp2, FIX(0.707106781)); /* c4 */
- tmp1 = tmp0 + tmp10;
- tmp11 = RIGHT_SHIFT(tmp0 - tmp10 - tmp10, CONST_BITS-PASS1_BITS);
- tmp10 = DEQUANTIZE(inptr[DCTSIZE*2], quantptr[DCTSIZE*2]);
- tmp0 = MULTIPLY(tmp10, FIX(1.224744871)); /* c2 */
- tmp10 = tmp1 + tmp0;
- tmp12 = tmp1 - tmp0;
- /* Odd part */
- z1 = DEQUANTIZE(inptr[DCTSIZE*1], quantptr[DCTSIZE*1]);
- z2 = DEQUANTIZE(inptr[DCTSIZE*3], quantptr[DCTSIZE*3]);
- z3 = DEQUANTIZE(inptr[DCTSIZE*5], quantptr[DCTSIZE*5]);
- tmp1 = MULTIPLY(z1 + z3, FIX(0.366025404)); /* c5 */
- tmp0 = tmp1 + ((z1 + z2) << CONST_BITS);
- tmp2 = tmp1 + ((z3 - z2) << CONST_BITS);
- tmp1 = (z1 - z2 - z3) << PASS1_BITS;
- /* Final output stage */
- wsptr[6*0] = (int) RIGHT_SHIFT(tmp10 + tmp0, CONST_BITS-PASS1_BITS);
- wsptr[6*5] = (int) RIGHT_SHIFT(tmp10 - tmp0, CONST_BITS-PASS1_BITS);
- wsptr[6*1] = (int) (tmp11 + tmp1);
- wsptr[6*4] = (int) (tmp11 - tmp1);
- wsptr[6*2] = (int) RIGHT_SHIFT(tmp12 + tmp2, CONST_BITS-PASS1_BITS);
- wsptr[6*3] = (int) RIGHT_SHIFT(tmp12 - tmp2, CONST_BITS-PASS1_BITS);
- }
- /* Pass 2: process 6 rows from work array, store into output array. */
- wsptr = workspace;
- for (ctr = 0; ctr < 6; ctr++) {
- outptr = output_buf[ctr] + output_col;
- /* Even part */
- /* Add fudge factor here for final descale. */
- tmp0 = (INT32) wsptr[0] + (ONE << (PASS1_BITS+2));
- tmp0 <<= CONST_BITS;
- tmp2 = (INT32) wsptr[4];
- tmp10 = MULTIPLY(tmp2, FIX(0.707106781)); /* c4 */
- tmp1 = tmp0 + tmp10;
- tmp11 = tmp0 - tmp10 - tmp10;
- tmp10 = (INT32) wsptr[2];
- tmp0 = MULTIPLY(tmp10, FIX(1.224744871)); /* c2 */
- tmp10 = tmp1 + tmp0;
- tmp12 = tmp1 - tmp0;
- /* Odd part */
- z1 = (INT32) wsptr[1];
- z2 = (INT32) wsptr[3];
- z3 = (INT32) wsptr[5];
- tmp1 = MULTIPLY(z1 + z3, FIX(0.366025404)); /* c5 */
- tmp0 = tmp1 + ((z1 + z2) << CONST_BITS);
- tmp2 = tmp1 + ((z3 - z2) << CONST_BITS);
- tmp1 = (z1 - z2 - z3) << CONST_BITS;
- /* Final output stage */
- outptr[0] = range_limit[(int) RIGHT_SHIFT(tmp10 + tmp0,
- CONST_BITS+PASS1_BITS+3)
- & RANGE_MASK];
- outptr[5] = range_limit[(int) RIGHT_SHIFT(tmp10 - tmp0,
- CONST_BITS+PASS1_BITS+3)
- & RANGE_MASK];
- outptr[1] = range_limit[(int) RIGHT_SHIFT(tmp11 + tmp1,
- CONST_BITS+PASS1_BITS+3)
- & RANGE_MASK];
- outptr[4] = range_limit[(int) RIGHT_SHIFT(tmp11 - tmp1,
- CONST_BITS+PASS1_BITS+3)
- & RANGE_MASK];
- outptr[2] = range_limit[(int) RIGHT_SHIFT(tmp12 + tmp2,
- CONST_BITS+PASS1_BITS+3)
- & RANGE_MASK];
- outptr[3] = range_limit[(int) RIGHT_SHIFT(tmp12 - tmp2,
- CONST_BITS+PASS1_BITS+3)
- & RANGE_MASK];
- wsptr += 6; /* advance pointer to next row */
- }
- }
- /*
- * Perform dequantization and inverse DCT on one block of coefficients,
- * producing a reduced-size 5x5 output block.
- *
- * Optimized algorithm with 5 multiplications in the 1-D kernel.
- * cK represents sqrt(2) * cos(K*pi/10).
- */
- GLOBAL(void)
- jpeg_idct_5x5 (j_decompress_ptr cinfo, jpeg_component_info * compptr,
- JCOEFPTR coef_block,
- JSAMPARRAY output_buf, JDIMENSION output_col)
- {
- INT32 tmp0, tmp1, tmp10, tmp11, tmp12;
- INT32 z1, z2, z3;
- JCOEFPTR inptr;
- ISLOW_MULT_TYPE * quantptr;
- int * wsptr;
- JSAMPROW outptr;
- JSAMPLE *range_limit = IDCT_range_limit(cinfo);
- int ctr;
- int workspace[5*5]; /* 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 = 0; ctr < 5; ctr++, inptr++, quantptr++, wsptr++) {
- /* Even part */
- tmp12 = DEQUANTIZE(inptr[DCTSIZE*0], quantptr[DCTSIZE*0]);
- tmp12 <<= CONST_BITS;
- /* Add fudge factor here for final descale. */
- tmp12 += ONE << (CONST_BITS-PASS1_BITS-1);
- tmp0 = DEQUANTIZE(inptr[DCTSIZE*2], quantptr[DCTSIZE*2]);
- tmp1 = DEQUANTIZE(inptr[DCTSIZE*4], quantptr[DCTSIZE*4]);
- z1 = MULTIPLY(tmp0 + tmp1, FIX(0.790569415)); /* (c2+c4)/2 */
- z2 = MULTIPLY(tmp0 - tmp1, FIX(0.353553391)); /* (c2-c4)/2 */
- z3 = tmp12 + z2;
- tmp10 = z3 + z1;
- tmp11 = z3 - z1;
- tmp12 -= z2 << 2;
- /* Odd part */
- z2 = DEQUANTIZE(inptr[DCTSIZE*1], quantptr[DCTSIZE*1]);
- z3 = DEQUANTIZE(inptr[DCTSIZE*3], quantptr[DCTSIZE*3]);
- z1 = MULTIPLY(z2 + z3, FIX(0.831253876)); /* c3 */
- tmp0 = z1 + MULTIPLY(z2, FIX(0.513743148)); /* c1-c3 */
- tmp1 = z1 - MULTIPLY(z3, FIX(2.176250899)); /* c1+c3 */
- /* Final output stage */
- wsptr[5*0] = (int) RIGHT_SHIFT(tmp10 + tmp0, CONST_BITS-PASS1_BITS);
- wsptr[5*4] = (int) RIGHT_SHIFT(tmp10 - tmp0, CONST_BITS-PASS1_BITS);
- wsptr[5*1] = (int) RIGHT_SHIFT(tmp11 + tmp1, CONST_BITS-PASS1_BITS);
- wsptr[5*3] = (int) RIGHT_SHIFT(tmp11 - tmp1, CONST_BITS-PASS1_BITS);
- wsptr[5*2] = (int) RIGHT_SHIFT(tmp12, CONST_BITS-PASS1_BITS);
- }
- /* Pass 2: process 5 rows from work array, store into output array. */
- wsptr = workspace;
- for (ctr = 0; ctr < 5; ctr++) {
- outptr = output_buf[ctr] + output_col;
- /* Even part */
- /* Add fudge factor here for final descale. */
- tmp12 = (INT32) wsptr[0] + (ONE << (PASS1_BITS+2));
- tmp12 <<= CONST_BITS;
- tmp0 = (INT32) wsptr[2];
- tmp1 = (INT32) wsptr[4];
- z1 = MULTIPLY(tmp0 + tmp1, FIX(0.790569415)); /* (c2+c4)/2 */
- z2 = MULTIPLY(tmp0 - tmp1, FIX(0.353553391)); /* (c2-c4)/2 */
- z3 = tmp12 + z2;
- tmp10 = z3 + z1;
- tmp11 = z3 - z1;
- tmp12 -= z2 << 2;
- /* Odd part */
- z2 = (INT32) wsptr[1];
- z3 = (INT32) wsptr[3];
- z1 = MULTIPLY(z2 + z3, FIX(0.831253876)); /* c3 */
- tmp0 = z1 + MULTIPLY(z2, FIX(0.513743148)); /* c1-c3 */
- tmp1 = z1 - MULTIPLY(z3, FIX(2.176250899)); /* c1+c3 */
- /* Final output stage */
- outptr[0] = range_limit[(int) RIGHT_SHIFT(tmp10 + tmp0,
- CONST_BITS+PASS1_BITS+3)
- & RANGE_MASK];
- outptr[4] = range_limit[(int) RIGHT_SHIFT(tmp10 - tmp0,
- CONST_BITS+PASS1_BITS+3)
- & RANGE_MASK];
- outptr[1] = range_limit[(int) RIGHT_SHIFT(tmp11 + tmp1,
- CONST_BITS+PASS1_BITS+3)
- & RANGE_MASK];
- outptr[3] = range_limit[(int) RIGHT_SHIFT(tmp11 - tmp1,
- CONST_BITS+PASS1_BITS+3)
- & RANGE_MASK];
- outptr[2] = range_limit[(int) RIGHT_SHIFT(tmp12,
- CONST_BITS+PASS1_BITS+3)
- & RANGE_MASK];
- wsptr += 5; /* advance pointer to next row */
- }
- }
- /*
- * Perform dequantization and inverse DCT on one block of coefficients,
- * producing a reduced-size 4x4 output block.
- *
- * Optimized algorithm with 3 multiplications in the 1-D kernel.
- * cK represents sqrt(2) * cos(K*pi/16) [refers to 8-point IDCT].
- */
- 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;
- JCOEFPTR inptr;
- ISLOW_MULT_TYPE * quantptr;
- int * wsptr;
- JSAMPROW outptr;
- JSAMPLE *range_limit = IDCT_range_limit(cinfo);
- int ctr;
- int workspace[4*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 = 0; ctr < 4; ctr++, inptr++, quantptr++, wsptr++) {
- /* Even part */
- tmp0 = DEQUANTIZE(inptr[DCTSIZE*0], quantptr[DCTSIZE*0]);
- tmp2 = DEQUANTIZE(inptr[DCTSIZE*2], quantptr[DCTSIZE*2]);
-
- tmp10 = (tmp0 + tmp2) << PASS1_BITS;
- tmp12 = (tmp0 - tmp2) << PASS1_BITS;
- /* Odd part */
- /* Same rotation as in the even part of the 8x8 LL&M IDCT */
- z2 = DEQUANTIZE(inptr[DCTSIZE*1], quantptr[DCTSIZE*1]);
- z3 = DEQUANTIZE(inptr[DCTSIZE*3], quantptr[DCTSIZE*3]);
- z1 = MULTIPLY(z2 + z3, FIX_0_541196100); /* c6 */
- /* Add fudge factor here for final descale. */
- z1 += ONE << (CONST_BITS-PASS1_BITS-1);
- tmp0 = RIGHT_SHIFT(z1 + MULTIPLY(z2, FIX_0_765366865), /* c2-c6 */
- CONST_BITS-PASS1_BITS);
- tmp2 = RIGHT_SHIFT(z1 - MULTIPLY(z3, FIX_1_847759065), /* c2+c6 */
- CONST_BITS-PASS1_BITS);
- /* Final output stage */
- wsptr[4*0] = (int) (tmp10 + tmp0);
- wsptr[4*3] = (int) (tmp10 - tmp0);
- wsptr[4*1] = (int) (tmp12 + tmp2);
- wsptr[4*2] = (int) (tmp12 - tmp2);
- }
- /* 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;
- /* Even part */
- /* Add fudge factor here for final descale. */
- tmp0 = (INT32) wsptr[0] + (ONE << (PASS1_BITS+2));
- tmp2 = (INT32) wsptr[2];
- tmp10 = (tmp0 + tmp2) << CONST_BITS;
- tmp12 = (tmp0 - tmp2) << CONST_BITS;
- /* Odd part */
- /* Same rotation as in the even part of the 8x8 LL&M IDCT */
- z2 = (INT32) wsptr[1];
- z3 = (INT32) wsptr[3];
- z1 = MULTIPLY(z2 + z3, FIX_0_541196100); /* c6 */
- tmp0 = z1 + MULTIPLY(z2, FIX_0_765366865); /* c2-c6 */
- tmp2 = z1 - MULTIPLY(z3, FIX_1_847759065); /* c2+c6 */
- /* Final output stage */
- outptr[0] = range_limit[(int) RIGHT_SHIFT(tmp10 + tmp0,
- CONST_BITS+PASS1_BITS+3)
- & RANGE_MASK];
- outptr[3] = range_limit[(int) RIGHT_SHIFT(tmp10 - tmp0,
- CONST_BITS+PASS1_BITS+3)
- & RANGE_MASK];
- outptr[1] = range_limit[(int) RIGHT_SHIFT(tmp12 + tmp2,
- CONST_BITS+PASS1_BITS+3)
- & RANGE_MASK];
- outptr[2] = range_limit[(int) RIGHT_SHIFT(tmp12 - tmp2,
- CONST_BITS+PASS1_BITS+3)
- & RANGE_MASK];
- wsptr += 4; /* advance pointer to next row */
- }
- }
- /*
- * Perform dequantization and inverse DCT on one block of coefficients,
- * producing a reduced-size 3x3 output block.
- *
- * Optimized algorithm with 2 multiplications in the 1-D kernel.
- * cK represents sqrt(2) * cos(K*pi/6).
- */
- GLOBAL(void)
- jpeg_idct_3x3 (j_decompress_ptr cinfo, jpeg_component_info * compptr,
- JCOEFPTR coef_block,
- JSAMPARRAY output_buf, JDIMENSION output_col)
- {
- INT32 tmp0, tmp2, tmp10, tmp12;
- JCOEFPTR inptr;
- ISLOW_MULT_TYPE * quantptr;
- int * wsptr;
- JSAMPROW outptr;
- JSAMPLE *range_limit = IDCT_range_limit(cinfo);
- int ctr;
- int workspace[3*3]; /* 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 = 0; ctr < 3; ctr++, inptr++, quantptr++, wsptr++) {
- /* Even part */
- tmp0 = DEQUANTIZE(inptr[DCTSIZE*0], quantptr[DCTSIZE*0]);
- tmp0 <<= CONST_BITS;
- /* Add fudge factor here for final descale. */
- tmp0 += ONE << (CONST_BITS-PASS1_BITS-1);
- tmp2 = DEQUANTIZE(inptr[DCTSIZE*2], quantptr[DCTSIZE*2]);
- tmp12 = MULTIPLY(tmp2, FIX(0.707106781)); /* c2 */
- tmp10 = tmp0 + tmp12;
- tmp2 = tmp0 - tmp12 - tmp12;
- /* Odd part */
- tmp12 = DEQUANTIZE(inptr[DCTSIZE*1], quantptr[DCTSIZE*1]);
- tmp0 = MULTIPLY(tmp12, FIX(1.224744871)); /* c1 */
- /* Final output stage */
- wsptr[3*0] = (int) RIGHT_SHIFT(tmp10 + tmp0, CONST_BITS-PASS1_BITS);
- wsptr[3*2] = (int) RIGHT_SHIFT(tmp10 - tmp0, CONST_BITS-PASS1_BITS);
- wsptr[3*1] = (int) RIGHT_SHIFT(tmp2, CONST_BITS-PASS1_BITS);
- }
- /* Pass 2: process 3 rows from work array, store into output array. */
- wsptr = workspace;
- for (ctr = 0; ctr < 3; ctr++) {
- outptr = output_buf[ctr] + output_col;
- /* Even part */
- /* Add fudge factor here for final descale. */
- tmp0 = (INT32) wsptr[0] + (ONE << (PASS1_BITS+2));
- tmp0 <<= CONST_BITS;
- tmp2 = (INT32) wsptr[2];
- tmp12 = MULTIPLY(tmp2, FIX(0.707106781)); /* c2 */
- tmp10 = tmp0 + tmp12;
- tmp2 = tmp0 - tmp12 - tmp12;
- /* Odd part */
- tmp12 = (INT32) wsptr[1];
- tmp0 = MULTIPLY(tmp12, FIX(1.224744871)); /* c1 */
- /* Final output stage */
- outptr[0] = range_limit[(int) RIGHT_SHIFT(tmp10 + tmp0,
- CONST_BITS+PASS1_BITS+3)
- & RANGE_MASK];
- outptr[2] = range_limit[(int) RIGHT_SHIFT(tmp10 - tmp0,
- CONST_BITS+PASS1_BITS+3)
- & RANGE_MASK];
- outptr[1] = range_limit[(int) RIGHT_SHIFT(tmp2,
- CONST_BITS+PASS1_BITS+3)
- & RANGE_MASK];
- wsptr += 3; /* advance pointer to next row */
- }
- }
- /*
- * Perform dequantization and inverse DCT on one block of coefficients,
- * producing a reduced-size 2x2 output block.
- *
- * Multiplication-less algorithm.
- */
- GLOBAL(void)
- jpeg_idct_2x2 (j_decompress_ptr cinfo, jpeg_component_info * compptr,
- JCOEFPTR coef_block,
- JSAMPARRAY output_buf, JDIMENSION output_col)
- {
- INT32 tmp0, tmp1, tmp2, tmp3, tmp4, tmp5;
- ISLOW_MULT_TYPE * quantptr;
- JSAMPROW outptr;
- JSAMPLE *range_limit = IDCT_range_limit(cinfo);
- SHIFT_TEMPS
- /* Pass 1: process columns from input. */
- quantptr = (ISLOW_MULT_TYPE *) compptr->dct_table;
- /* Column 0 */
- tmp4 = DEQUANTIZE(coef_block[DCTSIZE*0], quantptr[DCTSIZE*0]);
- tmp5 = DEQUANTIZE(coef_block[DCTSIZE*1], quantptr[DCTSIZE*1]);
- /* Add fudge factor here for final descale. */
- tmp4 += ONE << 2;
- tmp0 = tmp4 + tmp5;
- tmp2 = tmp4 - tmp5;
- /* Column 1 */
- tmp4 = DEQUANTIZE(coef_block[DCTSIZE*0+1], quantptr[DCTSIZE*0+1]);
- tmp5 = DEQUANTIZE(coef_block[DCTSIZE*1+1], quantptr[DCTSIZE*1+1]);
- tmp1 = tmp4 + tmp5;
- tmp3 = tmp4 - tmp5;
- /* Pass 2: process 2 rows, store into output array. */
- /* Row 0 */
- outptr = output_buf[0] + output_col;
- outptr[0] = range_limit[(int) RIGHT_SHIFT(tmp0 + tmp1, 3) & RANGE_MASK];
- outptr[1] = range_limit[(int) RIGHT_SHIFT(tmp0 - tmp1, 3) & RANGE_MASK];
- /* Row 1 */
- outptr = output_buf[1] + output_col;
- outptr[0] = range_limit[(int) RIGHT_SHIFT(tmp2 + tmp3, 3) & RANGE_MASK];
- outptr[1] = range_limit[(int) RIGHT_SHIFT(tmp2 - tmp3, 3) & RANGE_MASK];
- }
- /*
- * Perform dequantization and inverse DCT on one block of coefficients,
- * producing a reduced-size 1x1 output block.
- *
- * We hardly need an inverse DCT routine for this: just take the
- * average pixel value, which is one-eighth of the DC coefficient.
- */
- 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
- /* 1x1 is trivial: just take the DC coefficient divided by 8. */
- 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];
- }
- /*
- * Perform dequantization and inverse DCT on one block of coefficients,
- * producing a 9x9 output block.
- *
- * Optimized algorithm with 10 multiplications in the 1-D kernel.
- * cK represents sqrt(2) * cos(K*pi/18).
- */
- GLOBAL(void)
- jpeg_idct_9x9 (j_decompress_ptr cinfo, jpeg_component_info * compptr,
- JCOEFPTR coef_block,
- JSAMPARRAY output_buf, JDIMENSION output_col)
- {
- INT32 tmp0, tmp1, tmp2, tmp3, tmp10, tmp11, tmp12, tmp13, tmp14;
- 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[8*9]; /* 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 = 0; ctr < 8; ctr++, inptr++, quantptr++, wsptr++) {
- /* Even part */
- tmp0 = DEQUANTIZE(inptr[DCTSIZE*0], quantptr[DCTSIZE*0]);
- tmp0 <<= CONST_BITS;
- /* Add fudge factor here for final descale. */
- tmp0 += ONE << (CONST_BITS-PASS1_BITS-1);
- z1 = DEQUANTIZE(inptr[DCTSIZE*2], quantptr[DCTSIZE*2]);
- z2 = DEQUANTIZE(inptr[DCTSIZE*4], quantptr[DCTSIZE*4]);
- z3 = DEQUANTIZE(inptr[DCTSIZE*6], quantptr[DCTSIZE*6]);
- tmp3 = MULTIPLY(z3, FIX(0.707106781)); /* c6 */
- tmp1 = tmp0 + tmp3;
- tmp2 = tmp0 - tmp3 - tmp3;
- tmp0 = MULTIPLY(z1 - z2, FIX(0.707106781)); /* c6 */
- tmp11 = tmp2 + tmp0;
- tmp14 = tmp2 - tmp0 - tmp0;
- tmp0 = MULTIPLY(z1 + z2, FIX(1.328926049)); /* c2 */
- tmp2 = MULTIPLY(z1, FIX(1.083350441)); /* c4 */
- tmp3 = MULTIPLY(z2, FIX(0.245575608)); /* c8 */
- tmp10 = tmp1 + tmp0 - tmp3;
- tmp12 = tmp1 - tmp0 + tmp2;
- tmp13 = tmp1 - tmp2 + tmp3;
- /* Odd part */
- z1 = DEQUANTIZE(inptr[DCTSIZE*1], quantptr[DCTSIZE*1]);
- z2 = DEQUANTIZE(inptr[DCTSIZE*3], quantptr[DCTSIZE*3]);
- z3 = DEQUANTIZE(inptr[DCTSIZE*5], quantptr[DCTSIZE*5]);
- z4 = DEQUANTIZE(inptr[DCTSIZE*7], quantptr[DCTSIZE*7]);
- z2 = MULTIPLY(z2, - FIX(1.224744871)); /* -c3 */
- tmp2 = MULTIPLY(z1 + z3, FIX(0.909038955)); /* c5 */
- tmp3 = MULTIPLY(z1 + z4, FIX(0.483689525)); /* c7 */
- tmp0 = tmp2 + tmp3 - z2;
- tmp1 = MULTIPLY(z3 - z4, FIX(1.392728481)); /* c1 */
- tmp2 += z2 - tmp1;
- tmp3 += z2 + tmp1;
- tmp1 = MULTIPLY(z1 - z3 - z4, FIX(1.224744871)); /* c3 */
- /* Final output stage */
- wsptr[8*0] = (int) RIGHT_SHIFT(tmp10 + tmp0, CONST_BITS-PASS1_BITS);
- wsptr[8*8] = (int) RIGHT_SHIFT(tmp10 - tmp0, CONST_BITS-PASS1_BITS);
- wsptr[8*1] = (int) RIGHT_SHIFT(tmp11 + tmp1, CONST_BITS-PASS1_BITS);
- wsptr[8*7] = (int) RIGHT_SHIFT(tmp11 - tmp1, CONST_BITS-PASS1_BITS);
- wsptr[8*2] = (int) RIGHT_SHIFT(tmp12 + tmp2, CONST_BITS-PASS1_BITS);
- wsptr[8*6] = (int) RIGHT_SHIFT(tmp12 - tmp2, CONST_BITS-PASS1_BITS);
- wsptr[8*3] = (int) RIGHT_SHIFT(tmp13 + tmp3, CONST_BITS-PASS1_BITS);
- wsptr[8*5] = (int) RIGHT_SHIFT(tmp13 - tmp3, CONST_BITS-PASS1_BITS);
- wsptr[8*4] = (int) RIGHT_SHIFT(tmp14, CONST_BITS-PASS1_BITS);
- }
- /* Pass 2: process 9 rows from work array, store into output array. */
- wsptr = workspace;
- for (ctr = 0; ctr < 9; ctr++) {
- outptr = output_buf[ctr] + output_col;
- /* Even part */
- /* Add fudge factor here for final descale. */
- tmp0 = (INT32) wsptr[0] + (ONE << (PASS1_BITS+2));
- tmp0 <<= CONST_BITS;
- z1 = (INT32) wsptr[2];
- z2 = (INT32) wsptr[4];
- z3 = (INT32) wsptr[6];
- tmp3 = MULTIPLY(z3, FIX(0.707106781)); /* c6 */
- tmp1 = tmp0 + tmp3;
- tmp2 = tmp0 - tmp3 - tmp3;
- tmp0 = MULTIPLY(z1 - z2, FIX(0.707106781)); /* c6 */
- tmp11 = tmp2 + tmp0;
- tmp14 = tmp2 - tmp0 - tmp0;
- tmp0 = MULTIPLY(z1 + z2, FIX(1.328926049)); /* c2 */
- tmp2 = MULTIPLY(z1, FIX(1.083350441)); /* c4 */
- tmp3 = MULTIPLY(z2, FIX(0.245575608)); /* c8 */
- tmp10 = tmp1 + tmp0 - tmp3;
- tmp12 = tmp1 - tmp0 + tmp2;
- tmp13 = tmp1 - tmp2 + tmp3;
- /* Odd part */
- z1 = (INT32) wsptr[1];
- z2 = (INT32) wsptr[3];
- z3 = (INT32) wsptr[5];
- z4 = (INT32) wsptr[7];
- z2 = MULTIPLY(z2, - FIX(1.224744871)); /* -c3 */
- tmp2 = MULTIPLY(z1 + z3, FIX(0.909038955)); /* c5 */
- tmp3 = MULTIPLY(z1 + z4, FIX(0.483689525)); /* c7 */
- tmp0 = tmp2 + tmp3 - z2;
- tmp1 = MULTIPLY(z3 - z4, FIX(1.392728481)); /* c1 */
- tmp2 += z2 - tmp1;
- tmp3 += z2 + tmp1;
- tmp1 = MULTIPLY(z1 - z3 - z4, FIX(1.224744871)); /* c3 */
- /* Final output stage */
- outptr[0] = range_limit[(int) RIGHT_SHIFT(tmp10 + tmp0,
- CONST_BITS+PASS1_BITS+3)
- & RANGE_MASK];
- outptr[8] = range_limit[(int) RIGHT_SHIFT(tmp10 - tmp0,
- CONST_BITS+PASS1_BITS+3)
- & RANGE_MASK];
- outptr[1] = range_limit[(int) RIGHT_SHIFT(tmp11 + tmp1,
- CONST_BITS+PASS1_BITS+3)
- & RANGE_MASK];
- outptr[7] = range_limit[(int) RIGHT_SHIFT(tmp11 - tmp1,
- CONST_BITS+PASS1_BITS+3)
- & RANGE_MASK];
- outptr[2] = range_limit[(int) RIGHT_SHIFT(tmp12 + tmp2,
- CONST_BITS+PASS1_BITS+3)
- & RANGE_MASK];
- outptr[6] = range_limit[(int) RIGHT_SHIFT(tmp12 - tmp2,
- CONST_BITS+PASS1_BITS+3)
- & RANGE_MASK];
- outptr[3] = range_limit[(int) RIGHT_SHIFT(tmp13 + tmp3,
- CONST_BITS+PASS1_BITS+3)
- & RANGE_MASK];
- outptr[5] = range_limit[(int) RIGHT_SHIFT(tmp13 - tmp3,
- CONST_BITS+PASS1_BITS+3)
- & RANGE_MASK];
- outptr[4] = range_limit[(int) RIGHT_SHIFT(tmp14,
- CONST_BITS+PASS1_BITS+3)
- & RANGE_MASK];
- wsptr += 8; /* advance pointer to next row */
- }
- }
- /*
- * Perform dequantization and inverse DCT on one block of coefficients,
- * producing a 10x10 output block.
- *
- * Optimized algorithm with 12 multiplications in the 1-D kernel.
- * cK represents sqrt(2) * cos(K*pi/20).
- */
- GLOBAL(void)
- jpeg_idct_10x10 (j_decompress_ptr cinfo, jpeg_component_info * compptr,
- JCOEFPTR coef_block,
- JSAMPARRAY output_buf, JDIMENSION output_col)
- {
- INT32 tmp10, tmp11, tmp12, tmp13, tmp14;
- INT32 tmp20, tmp21, tmp22, tmp23, tmp24;
- INT32 z1, z2, z3, z4, z5;
- JCOEFPTR inptr;
- ISLOW_MULT_TYPE * quantptr;
- int * wsptr;
- JSAMPROW outptr;
- JSAMPLE *range_limit = IDCT_range_limit(cinfo);
- int ctr;
- int workspace[8*10]; /* 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 = 0; ctr < 8; ctr++, inptr++, quantptr++, wsptr++) {
- /* Even part */
- z3 = DEQUANTIZE(inptr[DCTSIZE*0], quantptr[DCTSIZE*0]);
- z3 <<= CONST_BITS;
- /* Add fudge factor here for final descale. */
- z3 += ONE << (CONST_BITS-PASS1_BITS-1);
- z4 = DEQUANTIZE(inptr[DCTSIZE*4], quantptr[DCTSIZE*4]);
- z1 = MULTIPLY(z4, FIX(1.144122806)); /* c4 */
- z2 = MULTIPLY(z4, FIX(0.437016024)); /* c8 */
- tmp10 = z3 + z1;
- tmp11 = z3 - z2;
- tmp22 = RIGHT_SHIFT(z3 - ((z1 - z2) << 1), /* c0 = (c4-c8)*2 */
- CONST_BITS-PASS1_BITS);
- z2 = DEQUANTIZE(inptr[DCTSIZE*2], quantptr[DCTSIZE*2]);
- z3 = DEQUANTIZE(inptr[DCTSIZE*6], quantptr[DCTSIZE*6]);
- z1 = MULTIPLY(z2 + z3, FIX(0.831253876)); /* c6 */
- tmp12 = z1 + MULTIPLY(z2, FIX(0.513743148)); /* c2-c6 */
- tmp13 = z1 - MULTIPLY(z3, FIX(2.176250899)); /* c2+c6 */
- tmp20 = tmp10 + tmp12;
- tmp24 = tmp10 - tmp12;
- tmp21 = tmp11 + tmp13;
- tmp23 = tmp11 - tmp13;
- /* Odd part */
- z1 = DEQUANTIZE(inptr[DCTSIZE*1], quantptr[DCTSIZE*1]);
- z2 = DEQUANTIZE(inptr[DCTSIZE*3], quantptr[DCTSIZE*3]);
- z3 = DEQUANTIZE(inptr[DCTSIZE*5], quantptr[DCTSIZE*5]);
- z4 = DEQUANTIZE(inptr[DCTSIZE*7], quantptr[DCTSIZE*7]);
- tmp11 = z2 + z4;
- tmp13 = z2 - z4;
- tmp12 = MULTIPLY(tmp13, FIX(0.309016994)); /* (c3-c7)/2 */
- z5 = z3 << CONST_BITS;
- z2 = MULTIPLY(tmp11, FIX(0.951056516)); /* (c3+c7)/2 */
- z4 = z5 + tmp12;
- tmp10 = MULTIPLY(z1, FIX(1.396802247)) + z2 + z4; /* c1 */
- tmp14 = MULTIPLY(z1, FIX(0.221231742)) - z2 + z4; /* c9 */
- z2 = MULTIPLY(tmp11, FIX(0.587785252)); /* (c1-c9)/2 */
- z4 = z5 - tmp12 - (tmp13 << (CONST_BITS - 1));
- tmp12 = (z1 - tmp13 - z3) << PASS1_BITS;
- tmp11 = MULTIPLY(z1, FIX(1.260073511)) - z2 - z4; /* c3 */
- tmp13 = MULTIPLY(z1, FIX(0.642039522)) - z2 + z4; /* c7 */
- /* Final output stage */
- wsptr[8*0] = (int) RIGHT_SHIFT(tmp20 + tmp10, CONST_BITS-PASS1_BITS);
- wsptr[8*9] = (int) RIGHT_SHIFT(tmp20 - tmp10, CONST_BITS-PASS1_BITS);
- wsptr[8*1] = (int) RIGHT_SHIFT(tmp21 + tmp11, CONST_BITS-PASS1_BITS);
- wsptr[8*8] = (int) RIGHT_SHIFT(tmp21 - tmp11, CONST_BITS-PASS1_BITS);
- wsptr[8*2] = (int) (tmp22 + tmp12);
- wsptr[8*7] = (int) (tmp22 - tmp12);
- wsptr[8*3] = (int) RIGHT_SHIFT(tmp23 + tmp13, CONST_BITS-PASS1_BITS);
- wsptr[8*6] = (int) RIGHT_SHIFT(tmp23 - tmp13, CONST_BITS-PASS1_BITS);
- wsptr[8*4] = (int) RIGHT_SHIFT(tmp24 + tmp14, CONST_BITS-PASS1_BITS);
- wsptr[8*5] = (int) RIGHT_SHIFT(tmp24 - tmp14, CONST_BITS-PASS1_BITS);
- }
- /* Pass 2: process 10 rows from work array, store into output array. */
- wsptr = workspace;
- for (ctr = 0; ctr < 10; ctr++) {
- outptr = output_buf[ctr] + output_col;
- /* Even part */
- /* Add fudge factor here for final descale. */
- z3 = (INT32) wsptr[0] + (ONE << (PASS1_BITS+2));
- z3 <<= CONST_BITS;
- z4 = (INT32) wsptr[4];
- z1 = MULTIPLY(z4, FIX(1.144122806)); /* c4 */
- z2 = MULTIPLY(z4, FIX(0.437016024)); /* c8 */
- tmp10 = z3 + z1;
- tmp11 = z3 - z2;
- tmp22 = z3 - ((z1 - z2) << 1); /* c0 = (c4-c8)*2 */
- z2 = (INT32) wsptr[2];
- z3 = (INT32) wsptr[6];
- z1 = MULTIPLY(z2 + z3, FIX(0.831253876)); /* c6 */
- tmp12 = z1 + MULTIPLY(z2, FIX(0.513743148)); /* c2-c6 */
- tmp13 = z1 - MULTIPLY(z3, FIX(2.176250899)); /* c2+c6 */
- tmp20 = tmp10 + tmp12;
- tmp24 = tmp10 - tmp12;
- tmp21 = tmp11 + tmp13;
- tmp23 = tmp11 - tmp13;
- /* Odd part */
- z1 = (INT32) wsptr[1];
- z2 = (INT32) wsptr[3];
- z3 = (INT32) wsptr[5];
- z3 <<= CONST_BITS;
- z4 = (INT32) wsptr[7];
- tmp11 = z2 + z4;
- tmp13 = z2 - z4;
- tmp12 = MULTIPLY(tmp13, FIX(0.309016994)); /* (c3-c7)/2 */
- z2 = MULTIPLY(tmp11, FIX(0.951056516)); /* (c3+c7)/2 */
- z4 = z3 + tmp12;
- tmp10 = MULTIPLY(z1, FIX(1.396802247)) + z2 + z4; /* c1 */
- tmp14 = MULTIPLY(z1, FIX(0.221231742)) - z2 + z4; /* c9 */
- z2 = MULTIPLY(tmp11, FIX(0.587785252)); /* (c1-c9)/2 */
- z4 = z3 - tmp12 - (tmp13 << (CONST_BITS - 1));
- tmp12 = ((z1 - tmp13) << CONST_BITS) - z3;
- tmp11 = MULTIPLY(z1, FIX(1.260073511)) - z2 - z4; /* c3 */
- tmp13 = MULTIPLY(z1, FIX(0.642039522)) - z2 + z4; /* c7 */
- /* Final output stage */
- outptr[0] = range_limit[(int) RIGHT_SHIFT(tmp20 + tmp10,
- CONST_BITS+PASS1_BITS+3)
- & RANGE_MASK];
- outptr[9] = range_limit[(int) RIGHT_SHIFT(tmp20 - tmp10,
- CONST_BITS+PASS1_BITS+3)
- & RANGE_MASK];
- outptr[1] = range_limit[(int) RIGHT_SHIFT(tmp21 + tmp11,
- CONST_BITS+PASS1_BITS+3)
- & RANGE_MASK];
- outptr[8] = range_limit[(int) RIGHT_SHIFT(tmp21 - tmp11,
- CONST_BITS+PASS1_BITS+3)
- & RANGE_MASK];
- outptr[2] = range_limit[(int) RIGHT_SHIFT(tmp22 + tmp12,
- CONST_BITS+PASS1_BITS+3)
- & RANGE_MASK];
- outptr[7] = range_limit[(int) RIGHT_SHIFT(tmp22 - tmp12,
- CONST_BITS+PASS1_BITS+3)
- & RANGE_MASK];
- outptr[3] = range_limit[(int) RIGHT_SHIFT(tmp23 + tmp13,
- CONST_BITS+PASS1_BITS+3)
- & RANGE_MASK];
- outptr[6] = range_limit[(int) RIGHT_SHIFT(tmp23 - tmp13,
- CONST_BITS+PASS1_BITS+3)
- & RANGE_MASK];
- outptr[4] = range_limit[(int) RIGHT_SHIFT(tmp24 + tmp14,
- CONST_BITS+PASS1_BITS+3)
- & RANGE_MASK];
- outptr[5] = range_limit[(int) RIGHT_SHIFT(tmp24 - tmp14,
- CONST_BITS+PASS1_BITS+3)
- & RANGE_MASK];
- wsptr += 8; /* advance pointer to next row */
- }
- }
- /*
- * Perform dequantization and inverse DCT on one block of coefficients,
- * producing a 11x11 output block.
- *
- * Optimized algorithm with 24 multiplications in the 1-D kernel.
- * cK represents sqrt(2) * cos(K*pi/22).
- */
- GLOBAL(void)
- jpeg_idct_11x11 (j_decompress_ptr cinfo, jpeg_component_info * compptr,
- JCOEFPTR coef_block,
- JSAMPARRAY output_buf, JDIMENSION output_col)
- {
- INT32 tmp10, tmp11, tmp…