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Diffstat (limited to '')
| -rw-r--r-- | media/libjpeg/jdct.h | 208 |
1 files changed, 208 insertions, 0 deletions
diff --git a/media/libjpeg/jdct.h b/media/libjpeg/jdct.h new file mode 100644 index 0000000000..66d1718b77 --- /dev/null +++ b/media/libjpeg/jdct.h @@ -0,0 +1,208 @@ +/* + * 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 |