diff options
Diffstat (limited to 'plugins/FreeImage/Source/LibJPEG/jfdctfst.c')
| -rw-r--r-- | plugins/FreeImage/Source/LibJPEG/jfdctfst.c | 460 | 
1 files changed, 230 insertions, 230 deletions
diff --git a/plugins/FreeImage/Source/LibJPEG/jfdctfst.c b/plugins/FreeImage/Source/LibJPEG/jfdctfst.c index 82b92317b0..8cad5f2293 100644 --- a/plugins/FreeImage/Source/LibJPEG/jfdctfst.c +++ b/plugins/FreeImage/Source/LibJPEG/jfdctfst.c @@ -1,230 +1,230 @@ -/*
 - * jfdctfst.c
 - *
 - * Copyright (C) 1994-1996, Thomas G. Lane.
 - * Modified 2003-2009 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 fast, not so accurate integer implementation of the
 - * forward DCT (Discrete Cosine Transform).
 - *
 - * A 2-D DCT can be done by 1-D DCT on each row followed by 1-D DCT
 - * 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.
 - *
 - * This implementation is based on Arai, Agui, and Nakajima's algorithm for
 - * scaled DCT.  Their original paper (Trans. IEICE E-71(11):1095) is in
 - * Japanese, but the algorithm is described in the Pennebaker & Mitchell
 - * JPEG textbook (see REFERENCES section in file README).  The following code
 - * is based directly on figure 4-8 in P&M.
 - * While an 8-point DCT cannot be done in less than 11 multiplies, it is
 - * possible to arrange the computation so that many of the multiplies are
 - * simple scalings of the final outputs.  These multiplies can then be
 - * folded into the multiplications or divisions by the JPEG quantization
 - * table entries.  The AA&N method leaves only 5 multiplies and 29 adds
 - * to be done in the DCT itself.
 - * The primary disadvantage of this method is that with fixed-point math,
 - * accuracy is lost due to imprecise representation of the scaled
 - * quantization values.  The smaller the quantization table entry, the less
 - * precise the scaled value, so this implementation does worse with high-
 - * quality-setting files than with low-quality ones.
 - */
 -
 -#define JPEG_INTERNALS
 -#include "jinclude.h"
 -#include "jpeglib.h"
 -#include "jdct.h"		/* Private declarations for DCT subsystem */
 -
 -#ifdef DCT_IFAST_SUPPORTED
 -
 -
 -/*
 - * This module is specialized to the case DCTSIZE = 8.
 - */
 -
 -#if DCTSIZE != 8
 -  Sorry, this code only copes with 8x8 DCTs. /* deliberate syntax err */
 -#endif
 -
 -
 -/* Scaling decisions are generally the same as in the LL&M algorithm;
 - * see jfdctint.c for more details.  However, we choose to descale
 - * (right shift) multiplication products as soon as they are formed,
 - * rather than carrying additional fractional bits into subsequent additions.
 - * This compromises accuracy slightly, but it lets us save a few shifts.
 - * More importantly, 16-bit arithmetic is then adequate (for 8-bit samples)
 - * everywhere except in the multiplications proper; this saves a good deal
 - * of work on 16-bit-int machines.
 - *
 - * Again to save a few shifts, the intermediate results between pass 1 and
 - * pass 2 are not upscaled, but are represented only to integral precision.
 - *
 - * A final compromise is to represent the multiplicative constants to only
 - * 8 fractional bits, rather than 13.  This saves some shifting work on some
 - * machines, and may also reduce the cost of multiplication (since there
 - * are fewer one-bits in the constants).
 - */
 -
 -#define CONST_BITS  8
 -
 -
 -/* 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 == 8
 -#define FIX_0_382683433  ((INT32)   98)		/* FIX(0.382683433) */
 -#define FIX_0_541196100  ((INT32)  139)		/* FIX(0.541196100) */
 -#define FIX_0_707106781  ((INT32)  181)		/* FIX(0.707106781) */
 -#define FIX_1_306562965  ((INT32)  334)		/* FIX(1.306562965) */
 -#else
 -#define FIX_0_382683433  FIX(0.382683433)
 -#define FIX_0_541196100  FIX(0.541196100)
 -#define FIX_0_707106781  FIX(0.707106781)
 -#define FIX_1_306562965  FIX(1.306562965)
 -#endif
 -
 -
 -/* We can gain a little more speed, with a further compromise in accuracy,
 - * by omitting the addition in a descaling shift.  This yields an incorrectly
 - * rounded result half the time...
 - */
 -
 -#ifndef USE_ACCURATE_ROUNDING
 -#undef DESCALE
 -#define DESCALE(x,n)  RIGHT_SHIFT(x, n)
 -#endif
 -
 -
 -/* Multiply a DCTELEM variable by an INT32 constant, and immediately
 - * descale to yield a DCTELEM result.
 - */
 -
 -#define MULTIPLY(var,const)  ((DCTELEM) DESCALE((var) * (const), CONST_BITS))
 -
 -
 -/*
 - * Perform the forward DCT on one block of samples.
 - */
 -
 -GLOBAL(void)
 -jpeg_fdct_ifast (DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col)
 -{
 -  DCTELEM tmp0, tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7;
 -  DCTELEM tmp10, tmp11, tmp12, tmp13;
 -  DCTELEM z1, z2, z3, z4, z5, z11, z13;
 -  DCTELEM *dataptr;
 -  JSAMPROW elemptr;
 -  int ctr;
 -  SHIFT_TEMPS
 -
 -  /* Pass 1: process rows. */
 -
 -  dataptr = data;
 -  for (ctr = 0; ctr < DCTSIZE; ctr++) {
 -    elemptr = sample_data[ctr] + start_col;
 -
 -    /* Load data into workspace */
 -    tmp0 = GETJSAMPLE(elemptr[0]) + GETJSAMPLE(elemptr[7]);
 -    tmp7 = GETJSAMPLE(elemptr[0]) - GETJSAMPLE(elemptr[7]);
 -    tmp1 = GETJSAMPLE(elemptr[1]) + GETJSAMPLE(elemptr[6]);
 -    tmp6 = GETJSAMPLE(elemptr[1]) - GETJSAMPLE(elemptr[6]);
 -    tmp2 = GETJSAMPLE(elemptr[2]) + GETJSAMPLE(elemptr[5]);
 -    tmp5 = GETJSAMPLE(elemptr[2]) - GETJSAMPLE(elemptr[5]);
 -    tmp3 = GETJSAMPLE(elemptr[3]) + GETJSAMPLE(elemptr[4]);
 -    tmp4 = GETJSAMPLE(elemptr[3]) - GETJSAMPLE(elemptr[4]);
 -
 -    /* Even part */
 -
 -    tmp10 = tmp0 + tmp3;	/* phase 2 */
 -    tmp13 = tmp0 - tmp3;
 -    tmp11 = tmp1 + tmp2;
 -    tmp12 = tmp1 - tmp2;
 -
 -    /* Apply unsigned->signed conversion */
 -    dataptr[0] = tmp10 + tmp11 - 8 * CENTERJSAMPLE; /* phase 3 */
 -    dataptr[4] = tmp10 - tmp11;
 -
 -    z1 = MULTIPLY(tmp12 + tmp13, FIX_0_707106781); /* c4 */
 -    dataptr[2] = tmp13 + z1;	/* phase 5 */
 -    dataptr[6] = tmp13 - z1;
 -
 -    /* Odd part */
 -
 -    tmp10 = tmp4 + tmp5;	/* phase 2 */
 -    tmp11 = tmp5 + tmp6;
 -    tmp12 = tmp6 + tmp7;
 -
 -    /* The rotator is modified from fig 4-8 to avoid extra negations. */
 -    z5 = MULTIPLY(tmp10 - tmp12, FIX_0_382683433); /* c6 */
 -    z2 = MULTIPLY(tmp10, FIX_0_541196100) + z5; /* c2-c6 */
 -    z4 = MULTIPLY(tmp12, FIX_1_306562965) + z5; /* c2+c6 */
 -    z3 = MULTIPLY(tmp11, FIX_0_707106781); /* c4 */
 -
 -    z11 = tmp7 + z3;		/* phase 5 */
 -    z13 = tmp7 - z3;
 -
 -    dataptr[5] = z13 + z2;	/* phase 6 */
 -    dataptr[3] = z13 - z2;
 -    dataptr[1] = z11 + z4;
 -    dataptr[7] = z11 - z4;
 -
 -    dataptr += DCTSIZE;		/* advance pointer to next row */
 -  }
 -
 -  /* Pass 2: process columns. */
 -
 -  dataptr = data;
 -  for (ctr = DCTSIZE-1; ctr >= 0; ctr--) {
 -    tmp0 = dataptr[DCTSIZE*0] + dataptr[DCTSIZE*7];
 -    tmp7 = dataptr[DCTSIZE*0] - dataptr[DCTSIZE*7];
 -    tmp1 = dataptr[DCTSIZE*1] + dataptr[DCTSIZE*6];
 -    tmp6 = dataptr[DCTSIZE*1] - dataptr[DCTSIZE*6];
 -    tmp2 = dataptr[DCTSIZE*2] + dataptr[DCTSIZE*5];
 -    tmp5 = dataptr[DCTSIZE*2] - dataptr[DCTSIZE*5];
 -    tmp3 = dataptr[DCTSIZE*3] + dataptr[DCTSIZE*4];
 -    tmp4 = dataptr[DCTSIZE*3] - dataptr[DCTSIZE*4];
 -
 -    /* Even part */
 -
 -    tmp10 = tmp0 + tmp3;	/* phase 2 */
 -    tmp13 = tmp0 - tmp3;
 -    tmp11 = tmp1 + tmp2;
 -    tmp12 = tmp1 - tmp2;
 -
 -    dataptr[DCTSIZE*0] = tmp10 + tmp11; /* phase 3 */
 -    dataptr[DCTSIZE*4] = tmp10 - tmp11;
 -
 -    z1 = MULTIPLY(tmp12 + tmp13, FIX_0_707106781); /* c4 */
 -    dataptr[DCTSIZE*2] = tmp13 + z1; /* phase 5 */
 -    dataptr[DCTSIZE*6] = tmp13 - z1;
 -
 -    /* Odd part */
 -
 -    tmp10 = tmp4 + tmp5;	/* phase 2 */
 -    tmp11 = tmp5 + tmp6;
 -    tmp12 = tmp6 + tmp7;
 -
 -    /* The rotator is modified from fig 4-8 to avoid extra negations. */
 -    z5 = MULTIPLY(tmp10 - tmp12, FIX_0_382683433); /* c6 */
 -    z2 = MULTIPLY(tmp10, FIX_0_541196100) + z5; /* c2-c6 */
 -    z4 = MULTIPLY(tmp12, FIX_1_306562965) + z5; /* c2+c6 */
 -    z3 = MULTIPLY(tmp11, FIX_0_707106781); /* c4 */
 -
 -    z11 = tmp7 + z3;		/* phase 5 */
 -    z13 = tmp7 - z3;
 -
 -    dataptr[DCTSIZE*5] = z13 + z2; /* phase 6 */
 -    dataptr[DCTSIZE*3] = z13 - z2;
 -    dataptr[DCTSIZE*1] = z11 + z4;
 -    dataptr[DCTSIZE*7] = z11 - z4;
 -
 -    dataptr++;			/* advance pointer to next column */
 -  }
 -}
 -
 -#endif /* DCT_IFAST_SUPPORTED */
 +/* + * jfdctfst.c + * + * Copyright (C) 1994-1996, Thomas G. Lane. + * Modified 2003-2009 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 fast, not so accurate integer implementation of the + * forward DCT (Discrete Cosine Transform). + * + * A 2-D DCT can be done by 1-D DCT on each row followed by 1-D DCT + * 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. + * + * This implementation is based on Arai, Agui, and Nakajima's algorithm for + * scaled DCT.  Their original paper (Trans. IEICE E-71(11):1095) is in + * Japanese, but the algorithm is described in the Pennebaker & Mitchell + * JPEG textbook (see REFERENCES section in file README).  The following code + * is based directly on figure 4-8 in P&M. + * While an 8-point DCT cannot be done in less than 11 multiplies, it is + * possible to arrange the computation so that many of the multiplies are + * simple scalings of the final outputs.  These multiplies can then be + * folded into the multiplications or divisions by the JPEG quantization + * table entries.  The AA&N method leaves only 5 multiplies and 29 adds + * to be done in the DCT itself. + * The primary disadvantage of this method is that with fixed-point math, + * accuracy is lost due to imprecise representation of the scaled + * quantization values.  The smaller the quantization table entry, the less + * precise the scaled value, so this implementation does worse with high- + * quality-setting files than with low-quality ones. + */ + +#define JPEG_INTERNALS +#include "jinclude.h" +#include "jpeglib.h" +#include "jdct.h"		/* Private declarations for DCT subsystem */ + +#ifdef DCT_IFAST_SUPPORTED + + +/* + * This module is specialized to the case DCTSIZE = 8. + */ + +#if DCTSIZE != 8 +  Sorry, this code only copes with 8x8 DCTs. /* deliberate syntax err */ +#endif + + +/* Scaling decisions are generally the same as in the LL&M algorithm; + * see jfdctint.c for more details.  However, we choose to descale + * (right shift) multiplication products as soon as they are formed, + * rather than carrying additional fractional bits into subsequent additions. + * This compromises accuracy slightly, but it lets us save a few shifts. + * More importantly, 16-bit arithmetic is then adequate (for 8-bit samples) + * everywhere except in the multiplications proper; this saves a good deal + * of work on 16-bit-int machines. + * + * Again to save a few shifts, the intermediate results between pass 1 and + * pass 2 are not upscaled, but are represented only to integral precision. + * + * A final compromise is to represent the multiplicative constants to only + * 8 fractional bits, rather than 13.  This saves some shifting work on some + * machines, and may also reduce the cost of multiplication (since there + * are fewer one-bits in the constants). + */ + +#define CONST_BITS  8 + + +/* 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 == 8 +#define FIX_0_382683433  ((INT32)   98)		/* FIX(0.382683433) */ +#define FIX_0_541196100  ((INT32)  139)		/* FIX(0.541196100) */ +#define FIX_0_707106781  ((INT32)  181)		/* FIX(0.707106781) */ +#define FIX_1_306562965  ((INT32)  334)		/* FIX(1.306562965) */ +#else +#define FIX_0_382683433  FIX(0.382683433) +#define FIX_0_541196100  FIX(0.541196100) +#define FIX_0_707106781  FIX(0.707106781) +#define FIX_1_306562965  FIX(1.306562965) +#endif + + +/* We can gain a little more speed, with a further compromise in accuracy, + * by omitting the addition in a descaling shift.  This yields an incorrectly + * rounded result half the time... + */ + +#ifndef USE_ACCURATE_ROUNDING +#undef DESCALE +#define DESCALE(x,n)  RIGHT_SHIFT(x, n) +#endif + + +/* Multiply a DCTELEM variable by an INT32 constant, and immediately + * descale to yield a DCTELEM result. + */ + +#define MULTIPLY(var,const)  ((DCTELEM) DESCALE((var) * (const), CONST_BITS)) + + +/* + * Perform the forward DCT on one block of samples. + */ + +GLOBAL(void) +jpeg_fdct_ifast (DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col) +{ +  DCTELEM tmp0, tmp1, tmp2, tmp3, tmp4, tmp5, tmp6, tmp7; +  DCTELEM tmp10, tmp11, tmp12, tmp13; +  DCTELEM z1, z2, z3, z4, z5, z11, z13; +  DCTELEM *dataptr; +  JSAMPROW elemptr; +  int ctr; +  SHIFT_TEMPS + +  /* Pass 1: process rows. */ + +  dataptr = data; +  for (ctr = 0; ctr < DCTSIZE; ctr++) { +    elemptr = sample_data[ctr] + start_col; + +    /* Load data into workspace */ +    tmp0 = GETJSAMPLE(elemptr[0]) + GETJSAMPLE(elemptr[7]); +    tmp7 = GETJSAMPLE(elemptr[0]) - GETJSAMPLE(elemptr[7]); +    tmp1 = GETJSAMPLE(elemptr[1]) + GETJSAMPLE(elemptr[6]); +    tmp6 = GETJSAMPLE(elemptr[1]) - GETJSAMPLE(elemptr[6]); +    tmp2 = GETJSAMPLE(elemptr[2]) + GETJSAMPLE(elemptr[5]); +    tmp5 = GETJSAMPLE(elemptr[2]) - GETJSAMPLE(elemptr[5]); +    tmp3 = GETJSAMPLE(elemptr[3]) + GETJSAMPLE(elemptr[4]); +    tmp4 = GETJSAMPLE(elemptr[3]) - GETJSAMPLE(elemptr[4]); + +    /* Even part */ + +    tmp10 = tmp0 + tmp3;	/* phase 2 */ +    tmp13 = tmp0 - tmp3; +    tmp11 = tmp1 + tmp2; +    tmp12 = tmp1 - tmp2; + +    /* Apply unsigned->signed conversion */ +    dataptr[0] = tmp10 + tmp11 - 8 * CENTERJSAMPLE; /* phase 3 */ +    dataptr[4] = tmp10 - tmp11; + +    z1 = MULTIPLY(tmp12 + tmp13, FIX_0_707106781); /* c4 */ +    dataptr[2] = tmp13 + z1;	/* phase 5 */ +    dataptr[6] = tmp13 - z1; + +    /* Odd part */ + +    tmp10 = tmp4 + tmp5;	/* phase 2 */ +    tmp11 = tmp5 + tmp6; +    tmp12 = tmp6 + tmp7; + +    /* The rotator is modified from fig 4-8 to avoid extra negations. */ +    z5 = MULTIPLY(tmp10 - tmp12, FIX_0_382683433); /* c6 */ +    z2 = MULTIPLY(tmp10, FIX_0_541196100) + z5; /* c2-c6 */ +    z4 = MULTIPLY(tmp12, FIX_1_306562965) + z5; /* c2+c6 */ +    z3 = MULTIPLY(tmp11, FIX_0_707106781); /* c4 */ + +    z11 = tmp7 + z3;		/* phase 5 */ +    z13 = tmp7 - z3; + +    dataptr[5] = z13 + z2;	/* phase 6 */ +    dataptr[3] = z13 - z2; +    dataptr[1] = z11 + z4; +    dataptr[7] = z11 - z4; + +    dataptr += DCTSIZE;		/* advance pointer to next row */ +  } + +  /* Pass 2: process columns. */ + +  dataptr = data; +  for (ctr = DCTSIZE-1; ctr >= 0; ctr--) { +    tmp0 = dataptr[DCTSIZE*0] + dataptr[DCTSIZE*7]; +    tmp7 = dataptr[DCTSIZE*0] - dataptr[DCTSIZE*7]; +    tmp1 = dataptr[DCTSIZE*1] + dataptr[DCTSIZE*6]; +    tmp6 = dataptr[DCTSIZE*1] - dataptr[DCTSIZE*6]; +    tmp2 = dataptr[DCTSIZE*2] + dataptr[DCTSIZE*5]; +    tmp5 = dataptr[DCTSIZE*2] - dataptr[DCTSIZE*5]; +    tmp3 = dataptr[DCTSIZE*3] + dataptr[DCTSIZE*4]; +    tmp4 = dataptr[DCTSIZE*3] - dataptr[DCTSIZE*4]; + +    /* Even part */ + +    tmp10 = tmp0 + tmp3;	/* phase 2 */ +    tmp13 = tmp0 - tmp3; +    tmp11 = tmp1 + tmp2; +    tmp12 = tmp1 - tmp2; + +    dataptr[DCTSIZE*0] = tmp10 + tmp11; /* phase 3 */ +    dataptr[DCTSIZE*4] = tmp10 - tmp11; + +    z1 = MULTIPLY(tmp12 + tmp13, FIX_0_707106781); /* c4 */ +    dataptr[DCTSIZE*2] = tmp13 + z1; /* phase 5 */ +    dataptr[DCTSIZE*6] = tmp13 - z1; + +    /* Odd part */ + +    tmp10 = tmp4 + tmp5;	/* phase 2 */ +    tmp11 = tmp5 + tmp6; +    tmp12 = tmp6 + tmp7; + +    /* The rotator is modified from fig 4-8 to avoid extra negations. */ +    z5 = MULTIPLY(tmp10 - tmp12, FIX_0_382683433); /* c6 */ +    z2 = MULTIPLY(tmp10, FIX_0_541196100) + z5; /* c2-c6 */ +    z4 = MULTIPLY(tmp12, FIX_1_306562965) + z5; /* c2+c6 */ +    z3 = MULTIPLY(tmp11, FIX_0_707106781); /* c4 */ + +    z11 = tmp7 + z3;		/* phase 5 */ +    z13 = tmp7 - z3; + +    dataptr[DCTSIZE*5] = z13 + z2; /* phase 6 */ +    dataptr[DCTSIZE*3] = z13 - z2; +    dataptr[DCTSIZE*1] = z11 + z4; +    dataptr[DCTSIZE*7] = z11 - z4; + +    dataptr++;			/* advance pointer to next column */ +  } +} + +#endif /* DCT_IFAST_SUPPORTED */  | 
