| /* |
| * jddctmgr.c |
| * |
| * This file was part of the Independent JPEG Group's software: |
| * Copyright (C) 1994-1996, Thomas G. Lane. |
| * Modified 2002-2010 by Guido Vollbeding. |
| * libjpeg-turbo Modifications: |
| * Copyright 2009 Pierre Ossman <ossman@cendio.se> for Cendio AB |
| * Copyright (C) 2010, 2015, D. R. Commander. |
| * Copyright (C) 2013, MIPS Technologies, Inc., California. |
| * For conditions of distribution and use, see the accompanying README.ijg |
| * 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 "jpeglib.h" |
| #include "jdct.h" /* Private declarations for DCT subsystem */ |
| #include "jsimddct.h" |
| #include "jpegcomp.h" |
| |
| |
| /* |
| * 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: |
| if (jsimd_can_idct_2x2()) |
| method_ptr = jsimd_idct_2x2; |
| else |
| method_ptr = jpeg_idct_2x2; |
| method = JDCT_ISLOW; /* jidctred uses islow-style table */ |
| break; |
| case 3: |
| method_ptr = jpeg_idct_3x3; |
| method = JDCT_ISLOW; /* jidctint uses islow-style table */ |
| break; |
| case 4: |
| if (jsimd_can_idct_4x4()) |
| method_ptr = jsimd_idct_4x4; |
| else |
| method_ptr = jpeg_idct_4x4; |
| method = JDCT_ISLOW; /* jidctred uses islow-style table */ |
| break; |
| case 5: |
| method_ptr = jpeg_idct_5x5; |
| method = JDCT_ISLOW; /* jidctint uses islow-style table */ |
| break; |
| case 6: |
| #if defined(__mips__) |
| if (jsimd_can_idct_6x6()) |
| method_ptr = jsimd_idct_6x6; |
| else |
| #endif |
| method_ptr = jpeg_idct_6x6; |
| method = JDCT_ISLOW; /* jidctint uses islow-style table */ |
| break; |
| case 7: |
| method_ptr = jpeg_idct_7x7; |
| method = JDCT_ISLOW; /* jidctint uses islow-style table */ |
| break; |
| #endif |
| case DCTSIZE: |
| switch (cinfo->dct_method) { |
| #ifdef DCT_ISLOW_SUPPORTED |
| case JDCT_ISLOW: |
| if (jsimd_can_idct_islow()) |
| method_ptr = jsimd_idct_islow; |
| else |
| method_ptr = jpeg_idct_islow; |
| method = JDCT_ISLOW; |
| break; |
| #endif |
| #ifdef DCT_IFAST_SUPPORTED |
| case JDCT_IFAST: |
| if (jsimd_can_idct_ifast()) |
| method_ptr = jsimd_idct_ifast; |
| else |
| method_ptr = jpeg_idct_ifast; |
| method = JDCT_IFAST; |
| break; |
| #endif |
| #ifdef DCT_FLOAT_SUPPORTED |
| case JDCT_FLOAT: |
| if (jsimd_can_idct_float()) |
| method_ptr = jsimd_idct_float; |
| else |
| method_ptr = jpeg_idct_float; |
| method = JDCT_FLOAT; |
| break; |
| #endif |
| default: |
| ERREXIT(cinfo, JERR_NOT_COMPILED); |
| break; |
| } |
| break; |
| #ifdef IDCT_SCALING_SUPPORTED |
| case 9: |
| method_ptr = jpeg_idct_9x9; |
| method = JDCT_ISLOW; /* jidctint uses islow-style table */ |
| break; |
| case 10: |
| method_ptr = jpeg_idct_10x10; |
| method = JDCT_ISLOW; /* jidctint uses islow-style table */ |
| break; |
| case 11: |
| method_ptr = jpeg_idct_11x11; |
| method = JDCT_ISLOW; /* jidctint uses islow-style table */ |
| break; |
| case 12: |
| #if defined(__mips__) |
| if (jsimd_can_idct_12x12()) |
| method_ptr = jsimd_idct_12x12; |
| else |
| #endif |
| method_ptr = jpeg_idct_12x12; |
| method = JDCT_ISLOW; /* jidctint uses islow-style table */ |
| break; |
| case 13: |
| method_ptr = jpeg_idct_13x13; |
| method = JDCT_ISLOW; /* jidctint uses islow-style table */ |
| break; |
| case 14: |
| method_ptr = jpeg_idct_14x14; |
| method = JDCT_ISLOW; /* jidctint uses islow-style table */ |
| break; |
| case 15: |
| method_ptr = jpeg_idct_15x15; |
| method = JDCT_ISLOW; /* jidctint uses islow-style table */ |
| break; |
| case 16: |
| method_ptr = jpeg_idct_16x16; |
| method = JDCT_ISLOW; /* jidctint uses islow-style table */ |
| break; |
| #endif |
| 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 as ints to ensure access efficiency. |
| */ |
| ISLOW_MULT_TYPE *ismtbl = (ISLOW_MULT_TYPE *)compptr->dct_table; |
| for (i = 0; i < DCTSIZE2; i++) { |
| ismtbl[i] = (ISLOW_MULT_TYPE)qtbl->quantval[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. |
| */ |
| 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((JLONG)qtbl->quantval[i], |
| (JLONG)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 |
| */ |
| 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[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; |
| } |
| } |
