+++ /dev/null
-/*
- * jddctmgr.c
- *
- * Copyright (C) 1994-1995, 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 inverse-DCT management logic.
- * This code selects a particular IDCT implementation to be used,
- * and it performs related housekeeping chores. No code in this file
- * is executed per IDCT step, only during output pass setup.
- *
- * Note that the IDCT routines are responsible for performing coefficient
- * dequantization as well as the IDCT proper. This module sets up the
- * dequantization multiplier table needed by the IDCT routine.
- */
-
-#define JPEG_INTERNALS
-#include "jinclude.h"
-#include "radiant_jpeglib.h"
-#include "jdct.h" /* Private declarations for DCT subsystem */
-
-
-/*
- * The decompressor input side (jdinput.c) saves away the appropriate
- * quantization table for each component at the start of the first scan
- * involving that component. (This is necessary in order to correctly
- * decode files that reuse Q-table slots.)
- * When we are ready to make an output pass, the saved Q-table is converted
- * to a multiplier table that will actually be used by the IDCT routine.
- * The multiplier table contents are IDCT-method-dependent. To support
- * application changes in IDCT method between scans, we can remake the
- * multiplier tables if necessary.
- * In buffered-image mode, the first output pass may occur before any data
- * has been seen for some components, and thus before their Q-tables have
- * been saved away. To handle this case, multiplier tables are preset
- * to zeroes; the result of the IDCT will be a neutral gray level.
- */
-
-
-/* Private subobject for this module */
-
-typedef struct {
- struct jpeg_inverse_dct pub; /* public fields */
-
- /* This array contains the IDCT method code that each multiplier table
- * is currently set up for, or -1 if it's not yet set up.
- * The actual multiplier tables are pointed to by dct_table in the
- * per-component comp_info structures.
- */
- int cur_method[MAX_COMPONENTS];
-} my_idct_controller;
-
-typedef my_idct_controller * my_idct_ptr;
-
-
-/* Allocated multiplier tables: big enough for any supported variant */
-
-typedef union {
- ISLOW_MULT_TYPE islow_array[DCTSIZE2];
-#ifdef DCT_IFAST_SUPPORTED
- IFAST_MULT_TYPE ifast_array[DCTSIZE2];
-#endif
-#ifdef DCT_FLOAT_SUPPORTED
- FLOAT_MULT_TYPE float_array[DCTSIZE2];
-#endif
-} multiplier_table;
-
-
-/* The current scaled-IDCT routines require ISLOW-style multiplier tables,
- * so be sure to compile that code if either ISLOW or SCALING is requested.
- */
-#ifdef DCT_ISLOW_SUPPORTED
-#define PROVIDE_ISLOW_TABLES
-#else
-#ifdef IDCT_SCALING_SUPPORTED
-#define PROVIDE_ISLOW_TABLES
-#endif
-#endif
-
-
-/*
- * Prepare for an output pass.
- * Here we select the proper IDCT routine for each component and build
- * a matching multiplier table.
- */
-
-METHODDEF void
-start_pass (j_decompress_ptr cinfo)
-{
- my_idct_ptr idct = (my_idct_ptr) cinfo->idct;
- int ci, i;
- jpeg_component_info *compptr;
- int method = 0;
- inverse_DCT_method_ptr method_ptr = NULL;
- JQUANT_TBL * qtbl;
-
- for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
- ci++, compptr++) {
- /* Select the proper IDCT routine for this component's scaling */
- switch (compptr->DCT_scaled_size) {
-#ifdef IDCT_SCALING_SUPPORTED
- case 1:
- method_ptr = jpeg_idct_1x1;
- method = JDCT_ISLOW; /* jidctred uses islow-style table */
- break;
- case 2:
- method_ptr = jpeg_idct_2x2;
- method = JDCT_ISLOW; /* jidctred uses islow-style table */
- break;
- case 4:
- method_ptr = jpeg_idct_4x4;
- method = JDCT_ISLOW; /* jidctred uses islow-style table */
- break;
-#endif
- case DCTSIZE:
- switch (cinfo->dct_method) {
-#ifdef DCT_ISLOW_SUPPORTED
- case JDCT_ISLOW:
- method_ptr = jpeg_idct_islow;
- method = JDCT_ISLOW;
- break;
-#endif
-#ifdef DCT_IFAST_SUPPORTED
- case JDCT_IFAST:
- method_ptr = jpeg_idct_ifast;
- method = JDCT_IFAST;
- break;
-#endif
-#ifdef DCT_FLOAT_SUPPORTED
- case JDCT_FLOAT:
- method_ptr = jpeg_idct_float;
- method = JDCT_FLOAT;
- break;
-#endif
- default:
- ERREXIT(cinfo, JERR_NOT_COMPILED);
- break;
- }
- break;
- default:
- ERREXIT1(cinfo, JERR_BAD_DCTSIZE, compptr->DCT_scaled_size);
- break;
- }
- idct->pub.inverse_DCT[ci] = method_ptr;
- /* Create multiplier table from quant table.
- * However, we can skip this if the component is uninteresting
- * or if we already built the table. Also, if no quant table
- * has yet been saved for the component, we leave the
- * multiplier table all-zero; we'll be reading zeroes from the
- * coefficient controller's buffer anyway.
- */
- if (! compptr->component_needed || idct->cur_method[ci] == method)
- continue;
- qtbl = compptr->quant_table;
- if (qtbl == NULL) /* happens if no data yet for component */
- continue;
- idct->cur_method[ci] = method;
- switch (method) {
-#ifdef PROVIDE_ISLOW_TABLES
- case JDCT_ISLOW:
- {
- /* For LL&M IDCT method, multipliers are equal to raw quantization
- * coefficients, but are stored in natural order as ints.
- */
- ISLOW_MULT_TYPE * ismtbl = (ISLOW_MULT_TYPE *) compptr->dct_table;
- for (i = 0; i < DCTSIZE2; i++) {
- ismtbl[i] = (ISLOW_MULT_TYPE) qtbl->quantval[jpeg_zigzag_order[i]];
- }
- }
- break;
-#endif
-#ifdef DCT_IFAST_SUPPORTED
- case JDCT_IFAST:
- {
- /* For AA&N IDCT method, multipliers 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
- * For integer operation, the multiplier table is to be scaled by
- * IFAST_SCALE_BITS. The multipliers are stored in natural order.
- */
- IFAST_MULT_TYPE * ifmtbl = (IFAST_MULT_TYPE *) compptr->dct_table;
-#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
-
- for (i = 0; i < DCTSIZE2; i++) {
- ifmtbl[i] = (IFAST_MULT_TYPE)
- DESCALE(MULTIPLY16V16((INT32) qtbl->quantval[jpeg_zigzag_order[i]],
- (INT32) aanscales[i]),
- CONST_BITS-IFAST_SCALE_BITS);
- }
- }
- break;
-#endif
-#ifdef DCT_FLOAT_SUPPORTED
- case JDCT_FLOAT:
- {
- /* For float AA&N IDCT method, multipliers 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
- * The multipliers are stored in natural order.
- */
- FLOAT_MULT_TYPE * fmtbl = (FLOAT_MULT_TYPE *) compptr->dct_table;
- int row, col;
- static const double aanscalefactor[DCTSIZE] = {
- 1.0, 1.387039845, 1.306562965, 1.175875602,
- 1.0, 0.785694958, 0.541196100, 0.275899379
- };
-
- i = 0;
- for (row = 0; row < DCTSIZE; row++) {
- for (col = 0; col < DCTSIZE; col++) {
- fmtbl[i] = (FLOAT_MULT_TYPE)
- ((double) qtbl->quantval[jpeg_zigzag_order[i]] *
- aanscalefactor[row] * aanscalefactor[col]);
- i++;
- }
- }
- }
- break;
-#endif
- default:
- ERREXIT(cinfo, JERR_NOT_COMPILED);
- break;
- }
- }
-}
-
-
-/*
- * Initialize IDCT manager.
- */
-
-GLOBAL void
-jinit_inverse_dct (j_decompress_ptr cinfo)
-{
- my_idct_ptr idct;
- int ci;
- jpeg_component_info *compptr;
-
- idct = (my_idct_ptr)
- (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
- SIZEOF(my_idct_controller));
- cinfo->idct = (struct jpeg_inverse_dct *) idct;
- idct->pub.start_pass = start_pass;
-
- for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
- ci++, compptr++) {
- /* Allocate and pre-zero a multiplier table for each component */
- compptr->dct_table =
- (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
- SIZEOF(multiplier_table));
- MEMZERO(compptr->dct_table, SIZEOF(multiplier_table));
- /* Mark multiplier table not yet set up for any method */
- idct->cur_method[ci] = -1;
- }
-}
projects / voretournament / voretournament.git / blobdiff