| /* |
| * jdct.h |
| * |
| * This file was part of the Independent JPEG Group's software: |
| * Copyright (C) 1994-1996, Thomas G. Lane. |
| * libjpeg-turbo Modifications: |
| * Copyright (C) 2015, D. R. Commander. |
| * For conditions of distribution and use, see the accompanying README.ijg |
| * 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, JLONG 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. This |
| * step requires an unsigned type and also one with twice the bits. |
| */ |
| |
| #if BITS_IN_JSAMPLE == 8 |
| #ifndef WITH_SIMD |
| typedef int DCTELEM; /* 16 or 32 bits is fine */ |
| typedef unsigned int UDCTELEM; |
| typedef unsigned long long UDCTELEM2; |
| #else |
| typedef short DCTELEM; /* prefer 16 bit with SIMD for parellelism */ |
| typedef unsigned short UDCTELEM; |
| typedef unsigned int UDCTELEM2; |
| #endif |
| #else |
| typedef JLONG DCTELEM; /* must have 32 bits */ |
| typedef unsigned long long UDCTELEM2; |
| #endif |
| |
| |
| /* |
| * 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 JLONG 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 */ |
| |
| |
| /* Extern declarations for the forward and inverse DCT routines. */ |
| |
| EXTERN(void) jpeg_fdct_islow(DCTELEM *data); |
| EXTERN(void) jpeg_fdct_ifast(DCTELEM *data); |
| EXTERN(void) jpeg_fdct_float(FAST_FLOAT *data); |
| |
| EXTERN(void) jpeg_idct_islow(j_decompress_ptr cinfo, |
| jpeg_component_info *compptr, JCOEFPTR coef_block, |
| JSAMPARRAY output_buf, JDIMENSION output_col); |
| EXTERN(void) jpeg_idct_ifast(j_decompress_ptr cinfo, |
| jpeg_component_info *compptr, JCOEFPTR coef_block, |
| JSAMPARRAY output_buf, JDIMENSION output_col); |
| EXTERN(void) jpeg_idct_float(j_decompress_ptr cinfo, |
| jpeg_component_info *compptr, JCOEFPTR coef_block, |
| JSAMPARRAY output_buf, JDIMENSION output_col); |
| EXTERN(void) jpeg_idct_7x7(j_decompress_ptr cinfo, |
| jpeg_component_info *compptr, JCOEFPTR coef_block, |
| JSAMPARRAY output_buf, JDIMENSION output_col); |
| EXTERN(void) jpeg_idct_6x6(j_decompress_ptr cinfo, |
| jpeg_component_info *compptr, JCOEFPTR coef_block, |
| JSAMPARRAY output_buf, JDIMENSION output_col); |
| EXTERN(void) jpeg_idct_5x5(j_decompress_ptr cinfo, |
| jpeg_component_info *compptr, JCOEFPTR coef_block, |
| JSAMPARRAY output_buf, JDIMENSION output_col); |
| EXTERN(void) jpeg_idct_4x4(j_decompress_ptr cinfo, |
| jpeg_component_info *compptr, JCOEFPTR coef_block, |
| JSAMPARRAY output_buf, JDIMENSION output_col); |
| EXTERN(void) jpeg_idct_3x3(j_decompress_ptr cinfo, |
| jpeg_component_info *compptr, JCOEFPTR coef_block, |
| JSAMPARRAY output_buf, JDIMENSION output_col); |
| EXTERN(void) jpeg_idct_2x2(j_decompress_ptr cinfo, |
| jpeg_component_info *compptr, JCOEFPTR coef_block, |
| JSAMPARRAY output_buf, JDIMENSION output_col); |
| EXTERN(void) jpeg_idct_1x1(j_decompress_ptr cinfo, |
| jpeg_component_info *compptr, JCOEFPTR coef_block, |
| JSAMPARRAY output_buf, JDIMENSION output_col); |
| EXTERN(void) jpeg_idct_9x9(j_decompress_ptr cinfo, |
| jpeg_component_info *compptr, JCOEFPTR coef_block, |
| JSAMPARRAY output_buf, JDIMENSION output_col); |
| EXTERN(void) jpeg_idct_10x10(j_decompress_ptr cinfo, |
| jpeg_component_info *compptr, JCOEFPTR coef_block, |
| JSAMPARRAY output_buf, JDIMENSION output_col); |
| EXTERN(void) jpeg_idct_11x11(j_decompress_ptr cinfo, |
| jpeg_component_info *compptr, JCOEFPTR coef_block, |
| JSAMPARRAY output_buf, JDIMENSION output_col); |
| EXTERN(void) jpeg_idct_12x12(j_decompress_ptr cinfo, |
| jpeg_component_info *compptr, JCOEFPTR coef_block, |
| JSAMPARRAY output_buf, JDIMENSION output_col); |
| EXTERN(void) jpeg_idct_13x13(j_decompress_ptr cinfo, |
| jpeg_component_info *compptr, JCOEFPTR coef_block, |
| JSAMPARRAY output_buf, JDIMENSION output_col); |
| EXTERN(void) jpeg_idct_14x14(j_decompress_ptr cinfo, |
| jpeg_component_info *compptr, JCOEFPTR coef_block, |
| JSAMPARRAY output_buf, JDIMENSION output_col); |
| EXTERN(void) jpeg_idct_15x15(j_decompress_ptr cinfo, |
| jpeg_component_info *compptr, JCOEFPTR coef_block, |
| JSAMPARRAY output_buf, JDIMENSION output_col); |
| EXTERN(void) jpeg_idct_16x16(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 JLONG. |
| * 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 ((JLONG)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) ((JLONG)((x) * CONST_SCALE + 0.5)) |
| |
| /* Descale and correctly round a JLONG 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 a JLONG variable by a JLONG constant to yield a JLONG 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)) * ((JLONG)(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 |
