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Diffstat (limited to 'code/jpeg-6/jdct.h')
| -rw-r--r-- | code/jpeg-6/jdct.h | 176 |
1 files changed, 0 insertions, 176 deletions
diff --git a/code/jpeg-6/jdct.h b/code/jpeg-6/jdct.h deleted file mode 100644 index 3ce790b..0000000 --- a/code/jpeg-6/jdct.h +++ /dev/null @@ -1,176 +0,0 @@ -/* - * jdct.h - * - * Copyright (C) 1994, 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 include file contains common declarations for the forward and - * inverse DCT modules. These declarations are private to the DCT managers - * (jcdctmgr.c, jddctmgr.c) and the individual DCT algorithms. - * The individual DCT algorithms are kept in separate files to ease - * machine-dependent tuning (e.g., assembly coding). - */ - - -/* - * A forward DCT routine is given a pointer to a work area of type DCTELEM[]; - * the DCT is to be performed in-place in that buffer. Type DCTELEM is int - * for 8-bit samples, INT32 for 12-bit samples. (NOTE: Floating-point DCT - * implementations use an array of type FAST_FLOAT, instead.) - * The DCT inputs are expected to be signed (range +-CENTERJSAMPLE). - * The DCT outputs are returned scaled up by a factor of 8; they therefore - * have a range of +-8K for 8-bit data, +-128K for 12-bit data. This - * convention improves accuracy in integer implementations and saves some - * work in floating-point ones. - * Quantization of the output coefficients is done by jcdctmgr.c. - */ - -#if BITS_IN_JSAMPLE == 8 -typedef int DCTELEM; /* 16 or 32 bits is fine */ -#else -typedef INT32 DCTELEM; /* must have 32 bits */ -#endif - -typedef JMETHOD(void, forward_DCT_method_ptr, (DCTELEM * data)); -typedef JMETHOD(void, float_DCT_method_ptr, (FAST_FLOAT * data)); - - -/* - * An inverse DCT routine is given a pointer to the input JBLOCK and a pointer - * to an output sample array. The routine must dequantize the input data as - * well as perform the IDCT; for dequantization, it uses the multiplier table - * pointed to by compptr->dct_table. The output data is to be placed into the - * sample array starting at a specified column. (Any row offset needed will - * be applied to the array pointer before it is passed to the IDCT code.) - * Note that the number of samples emitted by the IDCT routine is - * DCT_scaled_size * DCT_scaled_size. - */ - -/* typedef inverse_DCT_method_ptr is declared in jpegint.h */ - -/* - * Each IDCT routine has its own ideas about the best dct_table element type. - */ - -typedef MULTIPLIER ISLOW_MULT_TYPE; /* short or int, whichever is faster */ -#if BITS_IN_JSAMPLE == 8 -typedef MULTIPLIER IFAST_MULT_TYPE; /* 16 bits is OK, use short if faster */ -#define IFAST_SCALE_BITS 2 /* fractional bits in scale factors */ -#else -typedef INT32 IFAST_MULT_TYPE; /* need 32 bits for scaled quantizers */ -#define IFAST_SCALE_BITS 13 /* fractional bits in scale factors */ -#endif -typedef FAST_FLOAT FLOAT_MULT_TYPE; /* preferred floating type */ - - -/* - * Each IDCT routine is responsible for range-limiting its results and - * converting them to unsigned form (0..MAXJSAMPLE). The raw outputs could - * be quite far out of range if the input data is corrupt, so a bulletproof - * range-limiting step is required. We use a mask-and-table-lookup method - * to do the combined operations quickly. See the comments with - * prepare_range_limit_table (in jdmaster.c) for more info. - */ - -#define IDCT_range_limit(cinfo) ((cinfo)->sample_range_limit + CENTERJSAMPLE) - -#define RANGE_MASK (MAXJSAMPLE * 4 + 3) /* 2 bits wider than legal samples */ - - -/* Short forms of external names for systems with brain-damaged linkers. */ - -#ifdef NEED_SHORT_EXTERNAL_NAMES -#define jpeg_fdct_islow jFDislow -#define jpeg_fdct_ifast jFDifast -#define jpeg_fdct_float jFDfloat -#define jpeg_idct_islow jRDislow -#define jpeg_idct_ifast jRDifast -#define jpeg_idct_float jRDfloat -#define jpeg_idct_4x4 jRD4x4 -#define jpeg_idct_2x2 jRD2x2 -#define jpeg_idct_1x1 jRD1x1 -#endif /* NEED_SHORT_EXTERNAL_NAMES */ - -/* Extern declarations for the forward and inverse DCT routines. */ - -EXTERN void jpeg_fdct_islow JPP((DCTELEM * data)); -EXTERN void jpeg_fdct_ifast JPP((DCTELEM * data)); -EXTERN void jpeg_fdct_float JPP((FAST_FLOAT * data)); - -EXTERN void jpeg_idct_islow - JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, - JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); -EXTERN void jpeg_idct_ifast - JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, - JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); -EXTERN void jpeg_idct_float - JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, - JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); -EXTERN void jpeg_idct_4x4 - JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, - JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); -EXTERN void jpeg_idct_2x2 - JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, - JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); -EXTERN void jpeg_idct_1x1 - JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr, - JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col)); - - -/* - * Macros for handling fixed-point arithmetic; these are used by many - * but not all of the DCT/IDCT modules. - * - * All values are expected to be of type INT32. - * Fractional constants are scaled left by CONST_BITS bits. - * CONST_BITS is defined within each module using these macros, - * and may differ from one module to the next. - */ - -#define ONE ((INT32) 1) -#define CONST_SCALE (ONE << CONST_BITS) - -/* Convert a positive real constant to an integer scaled by CONST_SCALE. - * Caution: some C compilers fail to reduce "FIX(constant)" at compile time, - * thus causing a lot of useless floating-point operations at run time. - */ - -#define FIX(x) ((INT32) ((x) * CONST_SCALE + 0.5)) - -/* Descale and correctly round an INT32 value that's scaled by N bits. - * We assume RIGHT_SHIFT rounds towards minus infinity, so adding - * the fudge factor is correct for either sign of X. - */ - -#define DESCALE(x,n) RIGHT_SHIFT((x) + (ONE << ((n)-1)), n) - -/* Multiply an INT32 variable by an INT32 constant to yield an INT32 result. - * This macro is used only when the two inputs will actually be no more than - * 16 bits wide, so that a 16x16->32 bit multiply can be used instead of a - * full 32x32 multiply. This provides a useful speedup on many machines. - * Unfortunately there is no way to specify a 16x16->32 multiply portably - * in C, but some C compilers will do the right thing if you provide the - * correct combination of casts. - */ - -#ifdef SHORTxSHORT_32 /* may work if 'int' is 32 bits */ -#define MULTIPLY16C16(var,const) (((INT16) (var)) * ((INT16) (const))) -#endif -#ifdef SHORTxLCONST_32 /* known to work with Microsoft C 6.0 */ -#define MULTIPLY16C16(var,const) (((INT16) (var)) * ((INT32) (const))) -#endif - -#ifndef MULTIPLY16C16 /* default definition */ -#define MULTIPLY16C16(var,const) ((var) * (const)) -#endif - -/* Same except both inputs are variables. */ - -#ifdef SHORTxSHORT_32 /* may work if 'int' is 32 bits */ -#define MULTIPLY16V16(var1,var2) (((INT16) (var1)) * ((INT16) (var2))) -#endif - -#ifndef MULTIPLY16V16 /* default definition */ -#define MULTIPLY16V16(var1,var2) ((var1) * (var2)) -#endif |