* libjpeg-turbo Modifications:
* Copyright (C) 1999-2006, MIYASAKA Masaru.
* Copyright 2009 Pierre Ossman <ossman@cendio.se> for Cendio AB
- * Copyright (C) 2011 D. R. Commander
+ * Copyright (C) 2011, 2014-2015 D. R. Commander
* For conditions of distribution and use, see the accompanying README file.
*
* This file contains the forward-DCT management logic.
#define JPEG_INTERNALS
#include "jinclude.h"
#include "jpeglib.h"
-#include "jdct.h" /* Private declarations for DCT subsystem */
+#include "jdct.h" /* Private declarations for DCT subsystem */
#include "jsimddct.h"
/* Private subobject for this module */
-typedef JMETHOD(void, forward_DCT_method_ptr, (DCTELEM * data));
-typedef JMETHOD(void, float_DCT_method_ptr, (FAST_FLOAT * data));
+typedef void (*forward_DCT_method_ptr) (DCTELEM * data);
+typedef void (*float_DCT_method_ptr) (FAST_FLOAT * data);
-typedef JMETHOD(void, convsamp_method_ptr,
- (JSAMPARRAY sample_data, JDIMENSION start_col,
- DCTELEM * workspace));
-typedef JMETHOD(void, float_convsamp_method_ptr,
- (JSAMPARRAY sample_data, JDIMENSION start_col,
- FAST_FLOAT *workspace));
+typedef void (*convsamp_method_ptr) (JSAMPARRAY sample_data,
+ JDIMENSION start_col,
+ DCTELEM * workspace);
+typedef void (*float_convsamp_method_ptr) (JSAMPARRAY sample_data,
+ JDIMENSION start_col,
+ FAST_FLOAT *workspace);
-typedef JMETHOD(void, quantize_method_ptr,
- (JCOEFPTR coef_block, DCTELEM * divisors,
- DCTELEM * workspace));
-typedef JMETHOD(void, float_quantize_method_ptr,
- (JCOEFPTR coef_block, FAST_FLOAT * divisors,
- FAST_FLOAT * workspace));
+typedef void (*quantize_method_ptr) (JCOEFPTR coef_block, DCTELEM * divisors,
+ DCTELEM * workspace);
+typedef void (*float_quantize_method_ptr) (JCOEFPTR coef_block,
+ FAST_FLOAT * divisors,
+ FAST_FLOAT * workspace);
METHODDEF(void) quantize (JCOEFPTR, DCTELEM *, DCTELEM *);
typedef struct {
- struct jpeg_forward_dct pub; /* public fields */
+ struct jpeg_forward_dct pub; /* public fields */
/* Pointer to the DCT routine actually in use */
forward_DCT_method_ptr dct;
typedef my_fdct_controller * my_fdct_ptr;
+#if BITS_IN_JSAMPLE == 8
+
/*
* Find the highest bit in an integer through binary search.
*/
+
LOCAL(int)
flss (UINT16 val)
{
return bit;
}
+
/*
* Compute values to do a division using reciprocal.
*
*
* In order to allow SIMD implementations we also tweak the values to
* allow the same calculation to be made at all times:
- *
+ *
* dctbl[0] = f rounded to nearest integer
* dctbl[1] = divisor / 2 (+ 1 if fractional part of f < 0.5)
* dctbl[2] = 1 << ((word size) * 2 - r)
* of in a consecutive manner, yet again in order to allow SIMD
* routines.
*/
+
LOCAL(int)
compute_reciprocal (UINT16 divisor, DCTELEM * dtbl)
{
UDCTELEM c;
int b, r;
+ if (divisor == 1) {
+ /* divisor == 1 means unquantized, so these reciprocal/correction/shift
+ * values will cause the C quantization algorithm to act like the
+ * identity function. Since only the C quantization algorithm is used in
+ * these cases, the scale value is irrelevant.
+ */
+ dtbl[DCTSIZE2 * 0] = (DCTELEM) 1; /* reciprocal */
+ dtbl[DCTSIZE2 * 1] = (DCTELEM) 0; /* correction */
+ dtbl[DCTSIZE2 * 2] = (DCTELEM) 1; /* scale */
+ dtbl[DCTSIZE2 * 3] = (DCTELEM) (-sizeof(DCTELEM) * 8); /* shift */
+ return 0;
+ }
+
b = flss(divisor) - 1;
r = sizeof(DCTELEM) * 8 + b;
else return 1;
}
+#endif
+
+
/*
* Initialize for a processing pass.
* Verify that all referenced Q-tables are present, and set up
qtblno = compptr->quant_tbl_no;
/* Make sure specified quantization table is present */
if (qtblno < 0 || qtblno >= NUM_QUANT_TBLS ||
- cinfo->quant_tbl_ptrs[qtblno] == NULL)
+ cinfo->quant_tbl_ptrs[qtblno] == NULL)
ERREXIT1(cinfo, JERR_NO_QUANT_TABLE, qtblno);
qtbl = cinfo->quant_tbl_ptrs[qtblno];
/* Compute divisors for this quant table */
* coefficients multiplied by 8 (to counteract scaling).
*/
if (fdct->divisors[qtblno] == NULL) {
- fdct->divisors[qtblno] = (DCTELEM *)
- (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
- (DCTSIZE2 * 4) * SIZEOF(DCTELEM));
+ fdct->divisors[qtblno] = (DCTELEM *)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ (DCTSIZE2 * 4) * sizeof(DCTELEM));
}
dtbl = fdct->divisors[qtblno];
for (i = 0; i < DCTSIZE2; i++) {
- if(!compute_reciprocal(qtbl->quantval[i] << 3, &dtbl[i])
- && fdct->quantize == jsimd_quantize)
- fdct->quantize = quantize;
+#if BITS_IN_JSAMPLE == 8
+ if(!compute_reciprocal(qtbl->quantval[i] << 3, &dtbl[i])
+ && fdct->quantize == jsimd_quantize)
+ fdct->quantize = quantize;
+#else
+ dtbl[i] = ((DCTELEM) qtbl->quantval[i]) << 3;
+#endif
}
break;
#endif
#ifdef DCT_IFAST_SUPPORTED
case JDCT_IFAST:
{
- /* For AA&N IDCT method, divisors are equal to quantization
- * coefficients scaled by scalefactor[row]*scalefactor[col], where
- * scalefactor[0] = 1
- * scalefactor[k] = cos(k*PI/16) * sqrt(2) for k=1..7
- * We apply a further scale factor of 8.
- */
+ /* For AA&N IDCT method, divisors are equal to quantization
+ * coefficients scaled by scalefactor[row]*scalefactor[col], where
+ * scalefactor[0] = 1
+ * scalefactor[k] = cos(k*PI/16) * sqrt(2) for k=1..7
+ * We apply a further scale factor of 8.
+ */
#define CONST_BITS 14
- static const INT16 aanscales[DCTSIZE2] = {
- /* precomputed values scaled up by 14 bits */
- 16384, 22725, 21407, 19266, 16384, 12873, 8867, 4520,
- 22725, 31521, 29692, 26722, 22725, 17855, 12299, 6270,
- 21407, 29692, 27969, 25172, 21407, 16819, 11585, 5906,
- 19266, 26722, 25172, 22654, 19266, 15137, 10426, 5315,
- 16384, 22725, 21407, 19266, 16384, 12873, 8867, 4520,
- 12873, 17855, 16819, 15137, 12873, 10114, 6967, 3552,
- 8867, 12299, 11585, 10426, 8867, 6967, 4799, 2446,
- 4520, 6270, 5906, 5315, 4520, 3552, 2446, 1247
- };
- SHIFT_TEMPS
-
- if (fdct->divisors[qtblno] == NULL) {
- fdct->divisors[qtblno] = (DCTELEM *)
- (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
- (DCTSIZE2 * 4) * SIZEOF(DCTELEM));
- }
- dtbl = fdct->divisors[qtblno];
- for (i = 0; i < DCTSIZE2; i++) {
- if(!compute_reciprocal(
- DESCALE(MULTIPLY16V16((INT32) qtbl->quantval[i],
- (INT32) aanscales[i]),
- CONST_BITS-3), &dtbl[i])
- && fdct->quantize == jsimd_quantize)
- fdct->quantize = quantize;
- }
+ static const INT16 aanscales[DCTSIZE2] = {
+ /* precomputed values scaled up by 14 bits */
+ 16384, 22725, 21407, 19266, 16384, 12873, 8867, 4520,
+ 22725, 31521, 29692, 26722, 22725, 17855, 12299, 6270,
+ 21407, 29692, 27969, 25172, 21407, 16819, 11585, 5906,
+ 19266, 26722, 25172, 22654, 19266, 15137, 10426, 5315,
+ 16384, 22725, 21407, 19266, 16384, 12873, 8867, 4520,
+ 12873, 17855, 16819, 15137, 12873, 10114, 6967, 3552,
+ 8867, 12299, 11585, 10426, 8867, 6967, 4799, 2446,
+ 4520, 6270, 5906, 5315, 4520, 3552, 2446, 1247
+ };
+ SHIFT_TEMPS
+
+ if (fdct->divisors[qtblno] == NULL) {
+ fdct->divisors[qtblno] = (DCTELEM *)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ (DCTSIZE2 * 4) * sizeof(DCTELEM));
+ }
+ dtbl = fdct->divisors[qtblno];
+ for (i = 0; i < DCTSIZE2; i++) {
+#if BITS_IN_JSAMPLE == 8
+ if(!compute_reciprocal(
+ DESCALE(MULTIPLY16V16((INT32) qtbl->quantval[i],
+ (INT32) aanscales[i]),
+ CONST_BITS-3), &dtbl[i])
+ && fdct->quantize == jsimd_quantize)
+ fdct->quantize = quantize;
+#else
+ dtbl[i] = (DCTELEM)
+ DESCALE(MULTIPLY16V16((INT32) qtbl->quantval[i],
+ (INT32) aanscales[i]),
+ CONST_BITS-3);
+#endif
+ }
}
break;
#endif
#ifdef DCT_FLOAT_SUPPORTED
case JDCT_FLOAT:
{
- /* For float AA&N IDCT method, divisors are equal to quantization
- * coefficients scaled by scalefactor[row]*scalefactor[col], where
- * scalefactor[0] = 1
- * scalefactor[k] = cos(k*PI/16) * sqrt(2) for k=1..7
- * We apply a further scale factor of 8.
- * What's actually stored is 1/divisor so that the inner loop can
- * use a multiplication rather than a division.
- */
- FAST_FLOAT * fdtbl;
- int row, col;
- static const double aanscalefactor[DCTSIZE] = {
- 1.0, 1.387039845, 1.306562965, 1.175875602,
- 1.0, 0.785694958, 0.541196100, 0.275899379
- };
-
- if (fdct->float_divisors[qtblno] == NULL) {
- fdct->float_divisors[qtblno] = (FAST_FLOAT *)
- (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
- DCTSIZE2 * SIZEOF(FAST_FLOAT));
- }
- fdtbl = fdct->float_divisors[qtblno];
- i = 0;
- for (row = 0; row < DCTSIZE; row++) {
- for (col = 0; col < DCTSIZE; col++) {
- fdtbl[i] = (FAST_FLOAT)
- (1.0 / (((double) qtbl->quantval[i] *
- aanscalefactor[row] * aanscalefactor[col] * 8.0)));
- i++;
- }
- }
+ /* For float AA&N IDCT method, divisors are equal to quantization
+ * coefficients scaled by scalefactor[row]*scalefactor[col], where
+ * scalefactor[0] = 1
+ * scalefactor[k] = cos(k*PI/16) * sqrt(2) for k=1..7
+ * We apply a further scale factor of 8.
+ * What's actually stored is 1/divisor so that the inner loop can
+ * use a multiplication rather than a division.
+ */
+ FAST_FLOAT * fdtbl;
+ int row, col;
+ static const double aanscalefactor[DCTSIZE] = {
+ 1.0, 1.387039845, 1.306562965, 1.175875602,
+ 1.0, 0.785694958, 0.541196100, 0.275899379
+ };
+
+ if (fdct->float_divisors[qtblno] == NULL) {
+ fdct->float_divisors[qtblno] = (FAST_FLOAT *)
+ (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
+ DCTSIZE2 * sizeof(FAST_FLOAT));
+ }
+ fdtbl = fdct->float_divisors[qtblno];
+ i = 0;
+ for (row = 0; row < DCTSIZE; row++) {
+ for (col = 0; col < DCTSIZE; col++) {
+ fdtbl[i] = (FAST_FLOAT)
+ (1.0 / (((double) qtbl->quantval[i] *
+ aanscalefactor[row] * aanscalefactor[col] * 8.0)));
+ i++;
+ }
+ }
}
break;
#endif
for (elemr = 0; elemr < DCTSIZE; elemr++) {
elemptr = sample_data[elemr] + start_col;
-#if DCTSIZE == 8 /* unroll the inner loop */
+#if DCTSIZE == 8 /* unroll the inner loop */
*workspaceptr++ = GETJSAMPLE(*elemptr++) - CENTERJSAMPLE;
*workspaceptr++ = GETJSAMPLE(*elemptr++) - CENTERJSAMPLE;
*workspaceptr++ = GETJSAMPLE(*elemptr++) - CENTERJSAMPLE;
{
int i;
DCTELEM temp;
- UDCTELEM recip, corr, shift;
- UDCTELEM2 product;
JCOEFPTR output_ptr = coef_block;
+#if BITS_IN_JSAMPLE == 8
+
+ UDCTELEM recip, corr;
+ int shift;
+ UDCTELEM2 product;
+
for (i = 0; i < DCTSIZE2; i++) {
temp = workspace[i];
recip = divisors[i + DCTSIZE2 * 0];
product >>= shift + sizeof(DCTELEM)*8;
temp = product;
}
+ output_ptr[i] = (JCOEF) temp;
+ }
+
+#else
+
+ register DCTELEM qval;
+ for (i = 0; i < DCTSIZE2; i++) {
+ qval = divisors[i];
+ temp = workspace[i];
+ /* Divide the coefficient value by qval, ensuring proper rounding.
+ * Since C does not specify the direction of rounding for negative
+ * quotients, we have to force the dividend positive for portability.
+ *
+ * In most files, at least half of the output values will be zero
+ * (at default quantization settings, more like three-quarters...)
+ * so we should ensure that this case is fast. On many machines,
+ * a comparison is enough cheaper than a divide to make a special test
+ * a win. Since both inputs will be nonnegative, we need only test
+ * for a < b to discover whether a/b is 0.
+ * If your machine's division is fast enough, define FAST_DIVIDE.
+ */
+#ifdef FAST_DIVIDE
+#define DIVIDE_BY(a,b) a /= b
+#else
+#define DIVIDE_BY(a,b) if (a >= b) a /= b; else a = 0
+#endif
+ if (temp < 0) {
+ temp = -temp;
+ temp += qval>>1; /* for rounding */
+ DIVIDE_BY(temp, qval);
+ temp = -temp;
+ } else {
+ temp += qval>>1; /* for rounding */
+ DIVIDE_BY(temp, qval);
+ }
output_ptr[i] = (JCOEF) temp;
}
+
+#endif
+
}
METHODDEF(void)
forward_DCT (j_compress_ptr cinfo, jpeg_component_info * compptr,
- JSAMPARRAY sample_data, JBLOCKROW coef_blocks,
- JDIMENSION start_row, JDIMENSION start_col,
- JDIMENSION num_blocks)
+ JSAMPARRAY sample_data, JBLOCKROW coef_blocks,
+ JDIMENSION start_row, JDIMENSION start_col,
+ JDIMENSION num_blocks)
/* This version is used for integer DCT implementations. */
{
/* This routine is heavily used, so it's worth coding it tightly. */
quantize_method_ptr do_quantize = fdct->quantize;
workspace = fdct->workspace;
- sample_data += start_row; /* fold in the vertical offset once */
+ sample_data += start_row; /* fold in the vertical offset once */
for (bi = 0; bi < num_blocks; bi++, start_col += DCTSIZE) {
/* Load data into workspace, applying unsigned->signed conversion */
workspaceptr = workspace;
for (elemr = 0; elemr < DCTSIZE; elemr++) {
elemptr = sample_data[elemr] + start_col;
-#if DCTSIZE == 8 /* unroll the inner loop */
+#if DCTSIZE == 8 /* unroll the inner loop */
*workspaceptr++ = (FAST_FLOAT)(GETJSAMPLE(*elemptr++) - CENTERJSAMPLE);
*workspaceptr++ = (FAST_FLOAT)(GETJSAMPLE(*elemptr++) - CENTERJSAMPLE);
*workspaceptr++ = (FAST_FLOAT)(GETJSAMPLE(*elemptr++) - CENTERJSAMPLE);
METHODDEF(void)
forward_DCT_float (j_compress_ptr cinfo, jpeg_component_info * compptr,
- JSAMPARRAY sample_data, JBLOCKROW coef_blocks,
- JDIMENSION start_row, JDIMENSION start_col,
- JDIMENSION num_blocks)
+ JSAMPARRAY sample_data, JBLOCKROW coef_blocks,
+ JDIMENSION start_row, JDIMENSION start_col,
+ JDIMENSION num_blocks)
/* This version is used for floating-point DCT implementations. */
{
/* This routine is heavily used, so it's worth coding it tightly. */
float_quantize_method_ptr do_quantize = fdct->float_quantize;
workspace = fdct->float_workspace;
- sample_data += start_row; /* fold in the vertical offset once */
+ sample_data += start_row; /* fold in the vertical offset once */
for (bi = 0; bi < num_blocks; bi++, start_col += DCTSIZE) {
/* Load data into workspace, applying unsigned->signed conversion */
fdct = (my_fdct_ptr)
(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
- SIZEOF(my_fdct_controller));
+ sizeof(my_fdct_controller));
cinfo->fdct = (struct jpeg_forward_dct *) fdct;
fdct->pub.start_pass = start_pass_fdctmgr;
if (cinfo->dct_method == JDCT_FLOAT)
fdct->float_workspace = (FAST_FLOAT *)
(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
- SIZEOF(FAST_FLOAT) * DCTSIZE2);
+ sizeof(FAST_FLOAT) * DCTSIZE2);
else
#endif
fdct->workspace = (DCTELEM *)
(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
- SIZEOF(DCTELEM) * DCTSIZE2);
+ sizeof(DCTELEM) * DCTSIZE2);
/* Mark divisor tables unallocated */
for (i = 0; i < NUM_QUANT_TBLS; i++) {
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