19c791cdac
With rare exceptions ...
- Always separate line continuation characters by one space from
preceding code.
- Always use two-space indentation. Never use tabs.
- Always use K&R-style conditional blocks.
- Always surround operators with spaces, except in raw assembly code.
- Always put a space after, but not before, a comma.
- Never put a space between type casts and variables/function calls.
- Never put a space between the function name and the argument list in
function declarations and prototypes.
- Always surround braces ('{' and '}') with spaces.
- Always surround statements (if, for, else, catch, while, do, switch)
with spaces.
- Always attach pointer symbols ('*' and '**') to the variable or
function name.
- Always precede pointer symbols ('*' and '**') by a space in type
casts.
- Use the MIN() macro from jpegint.h within the libjpeg and TurboJPEG
API libraries (using min() from tjutil.h is still necessary for
TJBench.)
- Where it makes sense (particularly in the TurboJPEG code), put a blank
line after variable declaration blocks.
- Always separate statements in one-liners by two spaces.
The purpose of this was to ease maintenance on my part and also to make
it easier for contributors to figure out how to format patch
submissions. This was admittedly confusing (even to me sometimes) when
we had 3 or 4 different style conventions in the same source tree. The
new convention is more consistent with the formatting of other OSS code
bases.
This commit corrects deviations from the chosen formatting style in the
libjpeg API code and reformats the TurboJPEG API code such that it
conforms to the same standard.
NOTES:
- Although it is no longer necessary for the function name in function
declarations to begin in Column 1 (this was historically necessary
because of the ansi2knr utility, which allowed libjpeg to be built
with non-ANSI compilers), we retain that formatting for the libjpeg
code because it improves readability when using libjpeg's function
attribute macros (GLOBAL(), etc.)
- This reformatting project was accomplished with the help of AStyle and
Uncrustify, although neither was completely up to the task, and thus
a great deal of manual tweaking was required. Note to developers of
code formatting utilities: the libjpeg-turbo code base is an
excellent test bed, because AFAICT, it breaks every single one of the
utilities that are currently available.
- The legacy (MMX, SSE, 3DNow!) assembly code for i386 has been
formatted to match the SSE2 code (refer to
ff5685d5344273df321eb63a005eaae19d2496e3.) I hadn't intended to
bother with this, but the Loongson MMI implementation demonstrated
that there is still academic value to the MMX implementation, as an
algorithmic model for other 64-bit vector implementations. Thus, it
is desirable to improve its readability in the same manner as that of
the SSE2 implementation.
353 lines
11 KiB
C
353 lines
11 KiB
C
/*
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* jddctmgr.c
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*
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* This file was part of the Independent JPEG Group's software:
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* Copyright (C) 1994-1996, Thomas G. Lane.
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* Modified 2002-2010 by Guido Vollbeding.
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* libjpeg-turbo Modifications:
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* Copyright 2009 Pierre Ossman <ossman@cendio.se> for Cendio AB
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* Copyright (C) 2010, 2015, D. R. Commander.
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* Copyright (C) 2013, MIPS Technologies, Inc., California.
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* For conditions of distribution and use, see the accompanying README.ijg
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* file.
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*
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* This file contains the inverse-DCT management logic.
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* This code selects a particular IDCT implementation to be used,
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* and it performs related housekeeping chores. No code in this file
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* is executed per IDCT step, only during output pass setup.
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*
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* Note that the IDCT routines are responsible for performing coefficient
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* dequantization as well as the IDCT proper. This module sets up the
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* dequantization multiplier table needed by the IDCT routine.
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*/
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#define JPEG_INTERNALS
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#include "jinclude.h"
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#include "jpeglib.h"
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#include "jdct.h" /* Private declarations for DCT subsystem */
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#include "jsimddct.h"
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#include "jpegcomp.h"
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/*
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* The decompressor input side (jdinput.c) saves away the appropriate
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* quantization table for each component at the start of the first scan
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* involving that component. (This is necessary in order to correctly
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* decode files that reuse Q-table slots.)
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* When we are ready to make an output pass, the saved Q-table is converted
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* to a multiplier table that will actually be used by the IDCT routine.
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* The multiplier table contents are IDCT-method-dependent. To support
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* application changes in IDCT method between scans, we can remake the
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* multiplier tables if necessary.
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* In buffered-image mode, the first output pass may occur before any data
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* has been seen for some components, and thus before their Q-tables have
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* been saved away. To handle this case, multiplier tables are preset
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* to zeroes; the result of the IDCT will be a neutral gray level.
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*/
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/* Private subobject for this module */
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typedef struct {
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struct jpeg_inverse_dct pub; /* public fields */
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/* This array contains the IDCT method code that each multiplier table
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* is currently set up for, or -1 if it's not yet set up.
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* The actual multiplier tables are pointed to by dct_table in the
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* per-component comp_info structures.
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*/
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int cur_method[MAX_COMPONENTS];
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} my_idct_controller;
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typedef my_idct_controller *my_idct_ptr;
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/* Allocated multiplier tables: big enough for any supported variant */
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typedef union {
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ISLOW_MULT_TYPE islow_array[DCTSIZE2];
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#ifdef DCT_IFAST_SUPPORTED
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IFAST_MULT_TYPE ifast_array[DCTSIZE2];
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#endif
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#ifdef DCT_FLOAT_SUPPORTED
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FLOAT_MULT_TYPE float_array[DCTSIZE2];
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#endif
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} multiplier_table;
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/* The current scaled-IDCT routines require ISLOW-style multiplier tables,
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* so be sure to compile that code if either ISLOW or SCALING is requested.
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*/
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#ifdef DCT_ISLOW_SUPPORTED
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#define PROVIDE_ISLOW_TABLES
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#else
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#ifdef IDCT_SCALING_SUPPORTED
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#define PROVIDE_ISLOW_TABLES
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#endif
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#endif
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/*
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* Prepare for an output pass.
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* Here we select the proper IDCT routine for each component and build
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* a matching multiplier table.
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*/
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METHODDEF(void)
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start_pass(j_decompress_ptr cinfo)
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{
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my_idct_ptr idct = (my_idct_ptr)cinfo->idct;
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int ci, i;
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jpeg_component_info *compptr;
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int method = 0;
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inverse_DCT_method_ptr method_ptr = NULL;
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JQUANT_TBL *qtbl;
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for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
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ci++, compptr++) {
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/* Select the proper IDCT routine for this component's scaling */
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switch (compptr->_DCT_scaled_size) {
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#ifdef IDCT_SCALING_SUPPORTED
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case 1:
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method_ptr = jpeg_idct_1x1;
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method = JDCT_ISLOW; /* jidctred uses islow-style table */
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break;
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case 2:
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if (jsimd_can_idct_2x2())
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method_ptr = jsimd_idct_2x2;
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else
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method_ptr = jpeg_idct_2x2;
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method = JDCT_ISLOW; /* jidctred uses islow-style table */
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break;
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case 3:
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method_ptr = jpeg_idct_3x3;
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method = JDCT_ISLOW; /* jidctint uses islow-style table */
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break;
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case 4:
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if (jsimd_can_idct_4x4())
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method_ptr = jsimd_idct_4x4;
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else
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method_ptr = jpeg_idct_4x4;
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method = JDCT_ISLOW; /* jidctred uses islow-style table */
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break;
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case 5:
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method_ptr = jpeg_idct_5x5;
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method = JDCT_ISLOW; /* jidctint uses islow-style table */
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break;
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case 6:
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#if defined(__mips__)
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if (jsimd_can_idct_6x6())
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method_ptr = jsimd_idct_6x6;
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else
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#endif
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method_ptr = jpeg_idct_6x6;
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method = JDCT_ISLOW; /* jidctint uses islow-style table */
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break;
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case 7:
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method_ptr = jpeg_idct_7x7;
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method = JDCT_ISLOW; /* jidctint uses islow-style table */
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break;
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#endif
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case DCTSIZE:
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switch (cinfo->dct_method) {
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#ifdef DCT_ISLOW_SUPPORTED
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case JDCT_ISLOW:
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if (jsimd_can_idct_islow())
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method_ptr = jsimd_idct_islow;
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else
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method_ptr = jpeg_idct_islow;
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method = JDCT_ISLOW;
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break;
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#endif
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#ifdef DCT_IFAST_SUPPORTED
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case JDCT_IFAST:
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if (jsimd_can_idct_ifast())
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method_ptr = jsimd_idct_ifast;
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else
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method_ptr = jpeg_idct_ifast;
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method = JDCT_IFAST;
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break;
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#endif
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#ifdef DCT_FLOAT_SUPPORTED
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case JDCT_FLOAT:
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if (jsimd_can_idct_float())
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method_ptr = jsimd_idct_float;
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else
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method_ptr = jpeg_idct_float;
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method = JDCT_FLOAT;
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break;
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#endif
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default:
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ERREXIT(cinfo, JERR_NOT_COMPILED);
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break;
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}
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break;
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#ifdef IDCT_SCALING_SUPPORTED
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case 9:
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method_ptr = jpeg_idct_9x9;
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method = JDCT_ISLOW; /* jidctint uses islow-style table */
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break;
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case 10:
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method_ptr = jpeg_idct_10x10;
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method = JDCT_ISLOW; /* jidctint uses islow-style table */
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break;
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case 11:
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method_ptr = jpeg_idct_11x11;
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method = JDCT_ISLOW; /* jidctint uses islow-style table */
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break;
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case 12:
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#if defined(__mips__)
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if (jsimd_can_idct_12x12())
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method_ptr = jsimd_idct_12x12;
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else
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#endif
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method_ptr = jpeg_idct_12x12;
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method = JDCT_ISLOW; /* jidctint uses islow-style table */
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break;
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case 13:
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method_ptr = jpeg_idct_13x13;
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method = JDCT_ISLOW; /* jidctint uses islow-style table */
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break;
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case 14:
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method_ptr = jpeg_idct_14x14;
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method = JDCT_ISLOW; /* jidctint uses islow-style table */
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break;
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case 15:
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method_ptr = jpeg_idct_15x15;
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method = JDCT_ISLOW; /* jidctint uses islow-style table */
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break;
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case 16:
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method_ptr = jpeg_idct_16x16;
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method = JDCT_ISLOW; /* jidctint uses islow-style table */
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break;
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#endif
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default:
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ERREXIT1(cinfo, JERR_BAD_DCTSIZE, compptr->_DCT_scaled_size);
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break;
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}
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idct->pub.inverse_DCT[ci] = method_ptr;
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/* Create multiplier table from quant table.
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* However, we can skip this if the component is uninteresting
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* or if we already built the table. Also, if no quant table
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* has yet been saved for the component, we leave the
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* multiplier table all-zero; we'll be reading zeroes from the
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* coefficient controller's buffer anyway.
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*/
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if (!compptr->component_needed || idct->cur_method[ci] == method)
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continue;
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qtbl = compptr->quant_table;
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if (qtbl == NULL) /* happens if no data yet for component */
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continue;
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idct->cur_method[ci] = method;
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switch (method) {
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#ifdef PROVIDE_ISLOW_TABLES
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case JDCT_ISLOW:
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{
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/* For LL&M IDCT method, multipliers are equal to raw quantization
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* coefficients, but are stored as ints to ensure access efficiency.
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*/
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ISLOW_MULT_TYPE *ismtbl = (ISLOW_MULT_TYPE *)compptr->dct_table;
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for (i = 0; i < DCTSIZE2; i++) {
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ismtbl[i] = (ISLOW_MULT_TYPE)qtbl->quantval[i];
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}
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}
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break;
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#endif
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#ifdef DCT_IFAST_SUPPORTED
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case JDCT_IFAST:
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{
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/* For AA&N IDCT method, multipliers are equal to quantization
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* coefficients scaled by scalefactor[row]*scalefactor[col], where
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* scalefactor[0] = 1
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* scalefactor[k] = cos(k*PI/16) * sqrt(2) for k=1..7
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* For integer operation, the multiplier table is to be scaled by
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* IFAST_SCALE_BITS.
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*/
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IFAST_MULT_TYPE *ifmtbl = (IFAST_MULT_TYPE *)compptr->dct_table;
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#define CONST_BITS 14
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static const INT16 aanscales[DCTSIZE2] = {
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/* precomputed values scaled up by 14 bits */
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16384, 22725, 21407, 19266, 16384, 12873, 8867, 4520,
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22725, 31521, 29692, 26722, 22725, 17855, 12299, 6270,
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21407, 29692, 27969, 25172, 21407, 16819, 11585, 5906,
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19266, 26722, 25172, 22654, 19266, 15137, 10426, 5315,
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16384, 22725, 21407, 19266, 16384, 12873, 8867, 4520,
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12873, 17855, 16819, 15137, 12873, 10114, 6967, 3552,
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8867, 12299, 11585, 10426, 8867, 6967, 4799, 2446,
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4520, 6270, 5906, 5315, 4520, 3552, 2446, 1247
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};
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SHIFT_TEMPS
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for (i = 0; i < DCTSIZE2; i++) {
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ifmtbl[i] = (IFAST_MULT_TYPE)
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DESCALE(MULTIPLY16V16((JLONG)qtbl->quantval[i],
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(JLONG)aanscales[i]),
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CONST_BITS - IFAST_SCALE_BITS);
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}
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}
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break;
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#endif
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#ifdef DCT_FLOAT_SUPPORTED
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case JDCT_FLOAT:
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{
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/* For float AA&N IDCT method, multipliers are equal to quantization
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* coefficients scaled by scalefactor[row]*scalefactor[col], where
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* scalefactor[0] = 1
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* scalefactor[k] = cos(k*PI/16) * sqrt(2) for k=1..7
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*/
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FLOAT_MULT_TYPE *fmtbl = (FLOAT_MULT_TYPE *)compptr->dct_table;
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int row, col;
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static const double aanscalefactor[DCTSIZE] = {
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1.0, 1.387039845, 1.306562965, 1.175875602,
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1.0, 0.785694958, 0.541196100, 0.275899379
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};
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i = 0;
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for (row = 0; row < DCTSIZE; row++) {
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for (col = 0; col < DCTSIZE; col++) {
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fmtbl[i] = (FLOAT_MULT_TYPE)
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((double)qtbl->quantval[i] *
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aanscalefactor[row] * aanscalefactor[col]);
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i++;
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}
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}
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}
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break;
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#endif
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default:
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ERREXIT(cinfo, JERR_NOT_COMPILED);
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break;
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}
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}
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}
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/*
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* Initialize IDCT manager.
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*/
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GLOBAL(void)
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jinit_inverse_dct(j_decompress_ptr cinfo)
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{
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my_idct_ptr idct;
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int ci;
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jpeg_component_info *compptr;
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idct = (my_idct_ptr)
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(*cinfo->mem->alloc_small) ((j_common_ptr)cinfo, JPOOL_IMAGE,
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sizeof(my_idct_controller));
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cinfo->idct = (struct jpeg_inverse_dct *)idct;
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idct->pub.start_pass = start_pass;
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for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
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ci++, compptr++) {
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/* Allocate and pre-zero a multiplier table for each component */
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compptr->dct_table =
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(*cinfo->mem->alloc_small) ((j_common_ptr)cinfo, JPOOL_IMAGE,
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sizeof(multiplier_table));
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MEMZERO(compptr->dct_table, sizeof(multiplier_table));
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/* Mark multiplier table not yet set up for any method */
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idct->cur_method[ci] = -1;
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}
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}
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