CoCalc -- jdct.h

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Path: blob/master/libs/jpeg/jdct.h
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/*
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 * jdct.h
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 *
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 * Copyright (C) 1994-1996, Thomas G. Lane.
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 * Modified 2002-2023 by Guido Vollbeding.
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 * This file is part of the Independent JPEG Group's software.
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 * For conditions of distribution and use, see the accompanying README file.
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 *
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 * This include file contains common declarations for the forward and
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 * inverse DCT modules.  These declarations are private to the DCT managers
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 * (jcdctmgr.c, jddctmgr.c) and the individual DCT algorithms.
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 * The individual DCT algorithms are kept in separate files to ease 
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 * machine-dependent tuning (e.g., assembly coding).
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 */
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/*
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 * A forward DCT routine is given a pointer to an input sample array and
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 * a pointer to a work area of type DCTELEM[]; the DCT is to be performed
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 * in-place in that buffer.  Type DCTELEM is int for 8-bit samples, INT32
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 * for 12-bit samples.  (NOTE: Floating-point DCT implementations use an
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 * array of type FAST_FLOAT, instead.)
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 * The input data is to be fetched from the sample array starting at a
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 * specified column.  (Any row offset needed will be applied to the array
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 * pointer before it is passed to the FDCT code.)
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 * Note that the number of samples fetched by the FDCT routine is
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 * DCT_h_scaled_size * DCT_v_scaled_size.
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 * The DCT outputs are returned scaled up by a factor of 8; they therefore
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 * have a range of +-8K for 8-bit data, +-128K for 12-bit data.  This
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 * convention improves accuracy in integer implementations and saves some
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 * work in floating-point ones.
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 * Quantization of the output coefficients is done by jcdctmgr.c.
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 */
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#if BITS_IN_JSAMPLE == 8
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typedef int DCTELEM;		/* 16 or 32 bits is fine */
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#else
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typedef INT32 DCTELEM;		/* must have 32 bits */
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#endif
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typedef JMETHOD(void, forward_DCT_method_ptr, (DCTELEM * data,
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					       JSAMPARRAY sample_data,
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					       JDIMENSION start_col));
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typedef JMETHOD(void, float_DCT_method_ptr, (FAST_FLOAT * data,
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					     JSAMPARRAY sample_data,
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					     JDIMENSION start_col));
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/*
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 * An inverse DCT routine is given a pointer to the input JBLOCK and a pointer
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 * to an output sample array.  The routine must dequantize the input data as
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 * well as perform the IDCT; for dequantization, it uses the multiplier table
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 * pointed to by compptr->dct_table.  The output data is to be placed into the
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 * sample array starting at a specified column.  (Any row offset needed will
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 * be applied to the array pointer before it is passed to the IDCT code.)
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 * Note that the number of samples emitted by the IDCT routine is
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 * DCT_h_scaled_size * DCT_v_scaled_size.
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 */
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/* typedef inverse_DCT_method_ptr is declared in jpegint.h */
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/*
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 * Each IDCT routine has its own ideas about the best dct_table element type.
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 */
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typedef MULTIPLIER ISLOW_MULT_TYPE; /* short or int, whichever is faster */
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#if BITS_IN_JSAMPLE == 8
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typedef MULTIPLIER IFAST_MULT_TYPE; /* 16 bits is OK, use short if faster */
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#define IFAST_SCALE_BITS  2	/* fractional bits in scale factors */
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#else
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typedef INT32 IFAST_MULT_TYPE;	/* need 32 bits for scaled quantizers */
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#define IFAST_SCALE_BITS  13	/* fractional bits in scale factors */
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#endif
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typedef FAST_FLOAT FLOAT_MULT_TYPE; /* preferred floating type */
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/*
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 * Each IDCT routine is responsible for range-limiting its results and
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 * converting them to unsigned form (0..MAXJSAMPLE).  The raw outputs could
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 * be quite far out of range if the input data is corrupt, so a bulletproof
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 * range-limiting step is required.  We use a mask-and-table-lookup method
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 * to do the combined operations quickly, assuming that RANGE_CENTER
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 * (defined in jpegint.h) is a power of 2.  See the comments with
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 * prepare_range_limit_table (in jdmaster.c) for more info.
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 */
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#define RANGE_MASK  (RANGE_CENTER * 2 - 1)
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#define RANGE_SUBSET  (RANGE_CENTER - CENTERJSAMPLE)
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#define IDCT_range_limit(cinfo)  ((cinfo)->sample_range_limit - RANGE_SUBSET)
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/* Short forms of external names for systems with brain-damaged linkers. */
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#ifdef NEED_SHORT_EXTERNAL_NAMES
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#define jpeg_fdct_islow		jFDislow
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#define jpeg_fdct_ifast		jFDifast
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#define jpeg_fdct_float		jFDfloat
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#define jpeg_fdct_7x7		jFD7x7
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#define jpeg_fdct_6x6		jFD6x6
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#define jpeg_fdct_5x5		jFD5x5
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#define jpeg_fdct_4x4		jFD4x4
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#define jpeg_fdct_3x3		jFD3x3
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#define jpeg_fdct_2x2		jFD2x2
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#define jpeg_fdct_1x1		jFD1x1
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#define jpeg_fdct_9x9		jFD9x9
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#define jpeg_fdct_10x10		jFD10x10
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#define jpeg_fdct_11x11		jFD11x11
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#define jpeg_fdct_12x12		jFD12x12
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#define jpeg_fdct_13x13		jFD13x13
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#define jpeg_fdct_14x14		jFD14x14
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#define jpeg_fdct_15x15		jFD15x15
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#define jpeg_fdct_16x16		jFD16x16
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#define jpeg_fdct_16x8		jFD16x8
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#define jpeg_fdct_14x7		jFD14x7
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#define jpeg_fdct_12x6		jFD12x6
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#define jpeg_fdct_10x5		jFD10x5
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#define jpeg_fdct_8x4		jFD8x4
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#define jpeg_fdct_6x3		jFD6x3
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#define jpeg_fdct_4x2		jFD4x2
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#define jpeg_fdct_2x1		jFD2x1
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#define jpeg_fdct_8x16		jFD8x16
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#define jpeg_fdct_7x14		jFD7x14
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#define jpeg_fdct_6x12		jFD6x12
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#define jpeg_fdct_5x10		jFD5x10
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#define jpeg_fdct_4x8		jFD4x8
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#define jpeg_fdct_3x6		jFD3x6
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#define jpeg_fdct_2x4		jFD2x4
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#define jpeg_fdct_1x2		jFD1x2
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#define jpeg_idct_islow		jRDislow
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#define jpeg_idct_ifast		jRDifast
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#define jpeg_idct_float		jRDfloat
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#define jpeg_idct_7x7		jRD7x7
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#define jpeg_idct_6x6		jRD6x6
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#define jpeg_idct_5x5		jRD5x5
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#define jpeg_idct_4x4		jRD4x4
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#define jpeg_idct_3x3		jRD3x3
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#define jpeg_idct_2x2		jRD2x2
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#define jpeg_idct_1x1		jRD1x1
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#define jpeg_idct_9x9		jRD9x9
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#define jpeg_idct_10x10		jRD10x10
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#define jpeg_idct_11x11		jRD11x11
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#define jpeg_idct_12x12		jRD12x12
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#define jpeg_idct_13x13		jRD13x13
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#define jpeg_idct_14x14		jRD14x14
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#define jpeg_idct_15x15		jRD15x15
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#define jpeg_idct_16x16		jRD16x16
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#define jpeg_idct_16x8		jRD16x8
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#define jpeg_idct_14x7		jRD14x7
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#define jpeg_idct_12x6		jRD12x6
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#define jpeg_idct_10x5		jRD10x5
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#define jpeg_idct_8x4		jRD8x4
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#define jpeg_idct_6x3		jRD6x3
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#define jpeg_idct_4x2		jRD4x2
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#define jpeg_idct_2x1		jRD2x1
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#define jpeg_idct_8x16		jRD8x16
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#define jpeg_idct_7x14		jRD7x14
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#define jpeg_idct_6x12		jRD6x12
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#define jpeg_idct_5x10		jRD5x10
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#define jpeg_idct_4x8		jRD4x8
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#define jpeg_idct_3x6		jRD3x6
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#define jpeg_idct_2x4		jRD2x4
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#define jpeg_idct_1x2		jRD1x2
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#endif /* NEED_SHORT_EXTERNAL_NAMES */
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/* Extern declarations for the forward and inverse DCT routines. */
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EXTERN(void) jpeg_fdct_islow
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    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
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EXTERN(void) jpeg_fdct_ifast
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    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
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EXTERN(void) jpeg_fdct_float
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    JPP((FAST_FLOAT * data, JSAMPARRAY sample_data, JDIMENSION start_col));
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EXTERN(void) jpeg_fdct_7x7
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    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
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EXTERN(void) jpeg_fdct_6x6
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    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
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EXTERN(void) jpeg_fdct_5x5
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    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
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EXTERN(void) jpeg_fdct_4x4
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    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
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EXTERN(void) jpeg_fdct_3x3
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    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
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EXTERN(void) jpeg_fdct_2x2
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    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
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EXTERN(void) jpeg_fdct_1x1
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    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
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EXTERN(void) jpeg_fdct_9x9
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    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
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EXTERN(void) jpeg_fdct_10x10
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    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
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EXTERN(void) jpeg_fdct_11x11
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    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
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EXTERN(void) jpeg_fdct_12x12
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    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
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EXTERN(void) jpeg_fdct_13x13
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    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
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EXTERN(void) jpeg_fdct_14x14
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    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
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EXTERN(void) jpeg_fdct_15x15
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    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
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EXTERN(void) jpeg_fdct_16x16
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    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
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EXTERN(void) jpeg_fdct_16x8
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    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
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EXTERN(void) jpeg_fdct_14x7
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    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
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EXTERN(void) jpeg_fdct_12x6
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    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
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EXTERN(void) jpeg_fdct_10x5
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    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
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EXTERN(void) jpeg_fdct_8x4
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    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
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EXTERN(void) jpeg_fdct_6x3
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    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
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EXTERN(void) jpeg_fdct_4x2
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    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
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EXTERN(void) jpeg_fdct_2x1
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    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
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EXTERN(void) jpeg_fdct_8x16
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    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
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EXTERN(void) jpeg_fdct_7x14
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    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
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EXTERN(void) jpeg_fdct_6x12
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    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
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EXTERN(void) jpeg_fdct_5x10
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    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
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EXTERN(void) jpeg_fdct_4x8
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    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
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EXTERN(void) jpeg_fdct_3x6
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    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
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EXTERN(void) jpeg_fdct_2x4
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    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
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EXTERN(void) jpeg_fdct_1x2
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    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
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EXTERN(void) jpeg_idct_islow
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    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
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	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
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EXTERN(void) jpeg_idct_ifast
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    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
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	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
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EXTERN(void) jpeg_idct_float
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    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
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	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
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EXTERN(void) jpeg_idct_7x7
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    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
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	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
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EXTERN(void) jpeg_idct_6x6
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    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
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	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
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EXTERN(void) jpeg_idct_5x5
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    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
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	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
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EXTERN(void) jpeg_idct_4x4
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    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
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	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
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EXTERN(void) jpeg_idct_3x3
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    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
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	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
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EXTERN(void) jpeg_idct_2x2
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    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
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	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
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EXTERN(void) jpeg_idct_1x1
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    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
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	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
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EXTERN(void) jpeg_idct_9x9
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    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
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	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
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EXTERN(void) jpeg_idct_10x10
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    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
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	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
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EXTERN(void) jpeg_idct_11x11
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    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
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	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
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EXTERN(void) jpeg_idct_12x12
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    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
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	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
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EXTERN(void) jpeg_idct_13x13
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    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
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	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
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EXTERN(void) jpeg_idct_14x14
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    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
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	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
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EXTERN(void) jpeg_idct_15x15
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    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
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	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
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EXTERN(void) jpeg_idct_16x16
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    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
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	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
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EXTERN(void) jpeg_idct_16x8
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    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
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	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
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EXTERN(void) jpeg_idct_14x7
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    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
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	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
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EXTERN(void) jpeg_idct_12x6
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    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
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	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
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EXTERN(void) jpeg_idct_10x5
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    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
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	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
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EXTERN(void) jpeg_idct_8x4
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    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
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	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
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EXTERN(void) jpeg_idct_6x3
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    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
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	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
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EXTERN(void) jpeg_idct_4x2
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    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
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	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
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EXTERN(void) jpeg_idct_2x1
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    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
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	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
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EXTERN(void) jpeg_idct_8x16
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    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
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	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
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EXTERN(void) jpeg_idct_7x14
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    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
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	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
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EXTERN(void) jpeg_idct_6x12
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    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
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	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
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EXTERN(void) jpeg_idct_5x10
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    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
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	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
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EXTERN(void) jpeg_idct_4x8
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    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
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	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
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EXTERN(void) jpeg_idct_3x6
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    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
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	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
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EXTERN(void) jpeg_idct_2x4
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    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
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	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
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EXTERN(void) jpeg_idct_1x2
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    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
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	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
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/*
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 * Macros for handling fixed-point arithmetic; these are used by many
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 * but not all of the DCT/IDCT modules.
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 *
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 * All values are expected to be of type INT32.
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 * Fractional constants are scaled left by CONST_BITS bits.
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 * CONST_BITS is defined within each module using these macros,
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 * and may differ from one module to the next.
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 */
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#define ONE	((INT32) 1)
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#define CONST_SCALE (ONE << CONST_BITS)
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/* Convert a positive real constant to an integer scaled by CONST_SCALE.
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 * Caution: some C compilers fail to reduce "FIX(constant)" at compile time,
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 * thus causing a lot of useless floating-point operations at run time.
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 */
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#define FIX(x)	((INT32) ((x) * CONST_SCALE + 0.5))
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/* Multiply an INT32 variable by an INT32 constant to yield an INT32 result.
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 * This macro is used only when the two inputs will actually be no more than
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 * 16 bits wide, so that a 16x16->32 bit multiply can be used instead of a
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 * full 32x32 multiply.  This provides a useful speedup on many machines.
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 * Unfortunately there is no way to specify a 16x16->32 multiply portably
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 * in C, but some C compilers will do the right thing if you provide the
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 * correct combination of casts.
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 */
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#ifdef SHORTxSHORT_32		/* may work if 'int' is 32 bits */
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#define MULTIPLY16C16(var,const)  (((INT16) (var)) * ((INT16) (const)))
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#endif
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#ifdef SHORTxLCONST_32		/* known to work with Microsoft C 6.0 */
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#define MULTIPLY16C16(var,const)  (((INT16) (var)) * ((INT32) (const)))
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#endif
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#ifndef MULTIPLY16C16		/* default definition */
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#define MULTIPLY16C16(var,const)  ((var) * (const))
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#endif
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/* Same except both inputs are variables. */
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#ifdef SHORTxSHORT_32		/* may work if 'int' is 32 bits */
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#define MULTIPLY16V16(var1,var2)  (((INT16) (var1)) * ((INT16) (var2)))
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#endif
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#ifndef MULTIPLY16V16		/* default definition */
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#define MULTIPLY16V16(var1,var2)  ((var1) * (var2))
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#endif
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/* Like RIGHT_SHIFT, but applies to a DCTELEM.
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 * We assume that int right shift is unsigned if INT32 right shift is.
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 */
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#ifdef RIGHT_SHIFT_IS_UNSIGNED
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#define ISHIFT_TEMPS	DCTELEM ishift_temp;
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#if BITS_IN_JSAMPLE == 8
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#define DCTELEMBITS  16		/* DCTELEM may be 16 or 32 bits */
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#else
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#define DCTELEMBITS  32		/* DCTELEM must be 32 bits */
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#endif
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#define IRIGHT_SHIFT(x,shft)  \
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    ((ishift_temp = (x)) < 0 ? \
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     (ishift_temp >> (shft)) | ((~((DCTELEM) 0)) << (DCTELEMBITS-(shft))) : \
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     (ishift_temp >> (shft)))
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#else
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#define ISHIFT_TEMPS
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#define IRIGHT_SHIFT(x,shft)	((x) >> (shft))
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#endif
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