#if !defined(_FX_JPEG_TURBO_) | |
/* | |
* jcdctmgr.c | |
* | |
* Copyright (C) 1994-1996, Thomas G. Lane. | |
* 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 the forward-DCT management logic. | |
* This code selects a particular DCT implementation to be used, | |
* and it performs related housekeeping chores including coefficient | |
* quantization. | |
*/ | |
#define JPEG_INTERNALS | |
#include "jinclude.h" | |
#include "jpeglib.h" | |
#include "jdct.h" /* Private declarations for DCT subsystem */ | |
/* Private subobject for this module */ | |
typedef struct { | |
struct jpeg_forward_dct pub; /* public fields */ | |
/* Pointer to the DCT routine actually in use */ | |
forward_DCT_method_ptr do_dct; | |
/* The actual post-DCT divisors --- not identical to the quant table | |
* entries, because of scaling (especially for an unnormalized DCT). | |
* Each table is given in normal array order. | |
*/ | |
DCTELEM * divisors[NUM_QUANT_TBLS]; | |
#ifdef DCT_FLOAT_SUPPORTED | |
/* Same as above for the floating-point case. */ | |
float_DCT_method_ptr do_float_dct; | |
FAST_FLOAT * float_divisors[NUM_QUANT_TBLS]; | |
#endif | |
} my_fdct_controller; | |
typedef my_fdct_controller * my_fdct_ptr; | |
/* | |
* Initialize for a processing pass. | |
* Verify that all referenced Q-tables are present, and set up | |
* the divisor table for each one. | |
* In the current implementation, DCT of all components is done during | |
* the first pass, even if only some components will be output in the | |
* first scan. Hence all components should be examined here. | |
*/ | |
METHODDEF(void) | |
start_pass_fdctmgr (j_compress_ptr cinfo) | |
{ | |
my_fdct_ptr fdct = (my_fdct_ptr) cinfo->fdct; | |
int ci, qtblno, i; | |
jpeg_component_info *compptr; | |
JQUANT_TBL * qtbl; | |
DCTELEM * dtbl; | |
for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components; | |
ci++, compptr++) { | |
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) | |
ERREXIT1(cinfo, JERR_NO_QUANT_TABLE, qtblno); | |
qtbl = cinfo->quant_tbl_ptrs[qtblno]; | |
/* Compute divisors for this quant table */ | |
/* We may do this more than once for same table, but it's not a big deal */ | |
switch (cinfo->dct_method) { | |
#ifdef DCT_ISLOW_SUPPORTED | |
case JDCT_ISLOW: | |
/* For LL&M IDCT method, divisors are equal to raw quantization | |
* 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 * SIZEOF(DCTELEM)); | |
} | |
dtbl = fdct->divisors[qtblno]; | |
for (i = 0; i < DCTSIZE2; i++) { | |
dtbl[i] = ((DCTELEM) qtbl->quantval[i]) << 3; | |
} | |
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. | |
*/ | |
#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 * SIZEOF(DCTELEM)); | |
} | |
dtbl = fdct->divisors[qtblno]; | |
for (i = 0; i < DCTSIZE2; i++) { | |
dtbl[i] = (DCTELEM) | |
DESCALE(MULTIPLY16V16((INT32) qtbl->quantval[i], | |
(INT32) aanscales[i]), | |
CONST_BITS-3); | |
} | |
} | |
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++; | |
} | |
} | |
} | |
break; | |
#endif | |
default: | |
ERREXIT(cinfo, JERR_NOT_COMPILED); | |
break; | |
} | |
} | |
} | |
/* | |
* Perform forward DCT on one or more blocks of a component. | |
* | |
* The input samples are taken from the sample_data[] array starting at | |
* position start_row/start_col, and moving to the right for any additional | |
* blocks. The quantized coefficients are returned in coef_blocks[]. | |
*/ | |
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) | |
/* This version is used for integer DCT implementations. */ | |
{ | |
/* This routine is heavily used, so it's worth coding it tightly. */ | |
my_fdct_ptr fdct = (my_fdct_ptr) cinfo->fdct; | |
forward_DCT_method_ptr do_dct = fdct->do_dct; | |
DCTELEM * divisors = fdct->divisors[compptr->quant_tbl_no]; | |
DCTELEM workspace[DCTSIZE2]; /* work area for FDCT subroutine */ | |
JDIMENSION bi; | |
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 */ | |
{ register DCTELEM *workspaceptr; | |
register JSAMPROW elemptr; | |
register int elemr; | |
workspaceptr = workspace; | |
for (elemr = 0; elemr < DCTSIZE; elemr++) { | |
elemptr = sample_data[elemr] + start_col; | |
#if DCTSIZE == 8 /* unroll the inner loop */ | |
*workspaceptr++ = GETJSAMPLE(*elemptr++) - CENTERJSAMPLE; | |
*workspaceptr++ = GETJSAMPLE(*elemptr++) - CENTERJSAMPLE; | |
*workspaceptr++ = GETJSAMPLE(*elemptr++) - CENTERJSAMPLE; | |
*workspaceptr++ = GETJSAMPLE(*elemptr++) - CENTERJSAMPLE; | |
*workspaceptr++ = GETJSAMPLE(*elemptr++) - CENTERJSAMPLE; | |
*workspaceptr++ = GETJSAMPLE(*elemptr++) - CENTERJSAMPLE; | |
*workspaceptr++ = GETJSAMPLE(*elemptr++) - CENTERJSAMPLE; | |
*workspaceptr++ = GETJSAMPLE(*elemptr++) - CENTERJSAMPLE; | |
#else | |
{ register int elemc; | |
for (elemc = DCTSIZE; elemc > 0; elemc--) { | |
*workspaceptr++ = GETJSAMPLE(*elemptr++) - CENTERJSAMPLE; | |
} | |
} | |
#endif | |
} | |
} | |
/* Perform the DCT */ | |
(*do_dct) (workspace); | |
/* Quantize/descale the coefficients, and store into coef_blocks[] */ | |
{ register DCTELEM temp, qval; | |
register int i; | |
register JCOEFPTR output_ptr = coef_blocks[bi]; | |
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; | |
} | |
} | |
} | |
} | |
#ifdef DCT_FLOAT_SUPPORTED | |
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) | |
/* This version is used for floating-point DCT implementations. */ | |
{ | |
/* This routine is heavily used, so it's worth coding it tightly. */ | |
my_fdct_ptr fdct = (my_fdct_ptr) cinfo->fdct; | |
float_DCT_method_ptr do_dct = fdct->do_float_dct; | |
FAST_FLOAT * divisors = fdct->float_divisors[compptr->quant_tbl_no]; | |
FAST_FLOAT workspace[DCTSIZE2]; /* work area for FDCT subroutine */ | |
JDIMENSION bi; | |
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 */ | |
{ register FAST_FLOAT *workspaceptr; | |
register JSAMPROW elemptr; | |
register int elemr; | |
workspaceptr = workspace; | |
for (elemr = 0; elemr < DCTSIZE; elemr++) { | |
elemptr = sample_data[elemr] + start_col; | |
#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); | |
*workspaceptr++ = (FAST_FLOAT)(GETJSAMPLE(*elemptr++) - CENTERJSAMPLE); | |
*workspaceptr++ = (FAST_FLOAT)(GETJSAMPLE(*elemptr++) - CENTERJSAMPLE); | |
*workspaceptr++ = (FAST_FLOAT)(GETJSAMPLE(*elemptr++) - CENTERJSAMPLE); | |
*workspaceptr++ = (FAST_FLOAT)(GETJSAMPLE(*elemptr++) - CENTERJSAMPLE); | |
*workspaceptr++ = (FAST_FLOAT)(GETJSAMPLE(*elemptr++) - CENTERJSAMPLE); | |
#else | |
{ register int elemc; | |
for (elemc = DCTSIZE; elemc > 0; elemc--) { | |
*workspaceptr++ = (FAST_FLOAT) | |
(GETJSAMPLE(*elemptr++) - CENTERJSAMPLE); | |
} | |
} | |
#endif | |
} | |
} | |
/* Perform the DCT */ | |
(*do_dct) (workspace); | |
/* Quantize/descale the coefficients, and store into coef_blocks[] */ | |
{ register FAST_FLOAT temp; | |
register int i; | |
register JCOEFPTR output_ptr = coef_blocks[bi]; | |
for (i = 0; i < DCTSIZE2; i++) { | |
/* Apply the quantization and scaling factor */ | |
temp = workspace[i] * divisors[i]; | |
/* Round to nearest integer. | |
* Since C does not specify the direction of rounding for negative | |
* quotients, we have to force the dividend positive for portability. | |
* The maximum coefficient size is +-16K (for 12-bit data), so this | |
* code should work for either 16-bit or 32-bit ints. | |
*/ | |
output_ptr[i] = (JCOEF) ((int) (temp + (FAST_FLOAT) 16384.5) - 16384); | |
} | |
} | |
} | |
} | |
#endif /* DCT_FLOAT_SUPPORTED */ | |
/* | |
* Initialize FDCT manager. | |
*/ | |
GLOBAL(void) | |
jinit_forward_dct (j_compress_ptr cinfo) | |
{ | |
my_fdct_ptr fdct; | |
int i; | |
fdct = (my_fdct_ptr) | |
(*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE, | |
SIZEOF(my_fdct_controller)); | |
cinfo->fdct = (struct jpeg_forward_dct *) fdct; | |
fdct->pub.start_pass = start_pass_fdctmgr; | |
switch (cinfo->dct_method) { | |
#ifdef DCT_ISLOW_SUPPORTED | |
case JDCT_ISLOW: | |
fdct->pub.forward_DCT = forward_DCT; | |
fdct->do_dct = jpeg_fdct_islow; | |
break; | |
#endif | |
#ifdef DCT_IFAST_SUPPORTED | |
case JDCT_IFAST: | |
fdct->pub.forward_DCT = forward_DCT; | |
fdct->do_dct = jpeg_fdct_ifast; | |
break; | |
#endif | |
#ifdef DCT_FLOAT_SUPPORTED | |
case JDCT_FLOAT: | |
fdct->pub.forward_DCT = forward_DCT_float; | |
fdct->do_float_dct = jpeg_fdct_float; | |
break; | |
#endif | |
default: | |
ERREXIT(cinfo, JERR_NOT_COMPILED); | |
break; | |
} | |
/* Mark divisor tables unallocated */ | |
for (i = 0; i < NUM_QUANT_TBLS; i++) { | |
fdct->divisors[i] = NULL; | |
#ifdef DCT_FLOAT_SUPPORTED | |
fdct->float_divisors[i] = NULL; | |
#endif | |
} | |
} | |
#endif //_FX_JPEG_TURBO_ |