/src/libjpeg-turbo.main/jdct.h

Source (jump to first uncovered line)
/*
 * 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, 2022, 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).
 */

#include "jsamplecomp.h"


/*
 * 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) \
  ((_JSAMPLE *)((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

Coverage Report

Created: 2024-01-20 12:28

Line	Count	Source (jump to first uncovered line)
1		/*
2		* jdct.h
3		*
4		* This file was part of the Independent JPEG Group's software:
5		* Copyright (C) 1994-1996, Thomas G. Lane.
6		* libjpeg-turbo Modifications:
7		* Copyright (C) 2015, 2022, D. R. Commander.
8		* For conditions of distribution and use, see the accompanying README.ijg
9		* file.
10		*
11		* This include file contains common declarations for the forward and
12		* inverse DCT modules. These declarations are private to the DCT managers
13		* (jcdctmgr.c, jddctmgr.c) and the individual DCT algorithms.
14		* The individual DCT algorithms are kept in separate files to ease
15		* machine-dependent tuning (e.g., assembly coding).
16		*/
17
18		#include "jsamplecomp.h"
19
20
21		/*
22		* A forward DCT routine is given a pointer to a work area of type DCTELEM[];
23		* the DCT is to be performed in-place in that buffer. Type DCTELEM is int
24		* for 8-bit samples, JLONG for 12-bit samples. (NOTE: Floating-point DCT
25		* implementations use an array of type FAST_FLOAT, instead.)
26		* The DCT inputs are expected to be signed (range +-_CENTERJSAMPLE).
27		* The DCT outputs are returned scaled up by a factor of 8; they therefore
28		* have a range of +-8K for 8-bit data, +-128K for 12-bit data. This
29		* convention improves accuracy in integer implementations and saves some
30		* work in floating-point ones.
31		* Quantization of the output coefficients is done by jcdctmgr.c. This
32		* step requires an unsigned type and also one with twice the bits.
33		*/
34
35		#if BITS_IN_JSAMPLE == 8
36		#ifndef WITH_SIMD
37		typedef int DCTELEM; /* 16 or 32 bits is fine */
38		typedef unsigned int UDCTELEM;
39		typedef unsigned long long UDCTELEM2;
40		#else
41		typedef short DCTELEM; /* prefer 16 bit with SIMD for parellelism */
42		typedef unsigned short UDCTELEM;
43		typedef unsigned int UDCTELEM2;
44		#endif
45		#else
46		typedef JLONG DCTELEM; /* must have 32 bits */
47		typedef unsigned long long UDCTELEM2;
48		#endif
49
50
51		/*
52		* An inverse DCT routine is given a pointer to the input JBLOCK and a pointer
53		* to an output sample array. The routine must dequantize the input data as
54		* well as perform the IDCT; for dequantization, it uses the multiplier table
55		* pointed to by compptr->dct_table. The output data is to be placed into the
56		* sample array starting at a specified column. (Any row offset needed will
57		* be applied to the array pointer before it is passed to the IDCT code.)
58		* Note that the number of samples emitted by the IDCT routine is
59		* DCT_scaled_size * DCT_scaled_size.
60		*/
61
62		/* typedef inverse_DCT_method_ptr is declared in jpegint.h */
63
64		/*
65		* Each IDCT routine has its own ideas about the best dct_table element type.
66		*/
67
68		typedef MULTIPLIER ISLOW_MULT_TYPE; /* short or int, whichever is faster */
69		#if BITS_IN_JSAMPLE == 8
70		typedef MULTIPLIER IFAST_MULT_TYPE; /* 16 bits is OK, use short if faster */
71	71.6k	#define IFAST_SCALE_BITS 2 /* fractional bits in scale factors */
72		#else
73		typedef JLONG IFAST_MULT_TYPE; /* need 32 bits for scaled quantizers */
74		#define IFAST_SCALE_BITS 13 /* fractional bits in scale factors */
75		#endif
76		typedef FAST_FLOAT FLOAT_MULT_TYPE; /* preferred floating type */
77
78
79		/*
80		* Each IDCT routine is responsible for range-limiting its results and
81		* converting them to unsigned form (0.._MAXJSAMPLE). The raw outputs could
82		* be quite far out of range if the input data is corrupt, so a bulletproof
83		* range-limiting step is required. We use a mask-and-table-lookup method
84		* to do the combined operations quickly. See the comments with
85		* prepare_range_limit_table (in jdmaster.c) for more info.
86		*/
87
88		#define IDCT_range_limit(cinfo) \
89	67.4M	((_JSAMPLE *)((cinfo)->sample_range_limit) + _CENTERJSAMPLE)
90
91	1.40G	#define RANGE_MASK (_MAXJSAMPLE * 4 + 3) /* 2 bits wider than legal samples */
92
93
94		/* Extern declarations for the forward and inverse DCT routines. */
95
96		EXTERN(void) _jpeg_fdct_islow(DCTELEM *data);
97		EXTERN(void) _jpeg_fdct_ifast(DCTELEM *data);
98		EXTERN(void) jpeg_fdct_float(FAST_FLOAT *data);
99
100		EXTERN(void) _jpeg_idct_islow(j_decompress_ptr cinfo,
101		jpeg_component_info *compptr,
102		JCOEFPTR coef_block, _JSAMPARRAY output_buf,
103		JDIMENSION output_col);
104		EXTERN(void) _jpeg_idct_ifast(j_decompress_ptr cinfo,
105		jpeg_component_info *compptr,
106		JCOEFPTR coef_block, _JSAMPARRAY output_buf,
107		JDIMENSION output_col);
108		EXTERN(void) _jpeg_idct_float(j_decompress_ptr cinfo,
109		jpeg_component_info *compptr,
110		JCOEFPTR coef_block, _JSAMPARRAY output_buf,
111		JDIMENSION output_col);
112		EXTERN(void) _jpeg_idct_7x7(j_decompress_ptr cinfo,
113		jpeg_component_info *compptr, JCOEFPTR coef_block,
114		_JSAMPARRAY output_buf, JDIMENSION output_col);
115		EXTERN(void) _jpeg_idct_6x6(j_decompress_ptr cinfo,
116		jpeg_component_info *compptr, JCOEFPTR coef_block,
117		_JSAMPARRAY output_buf, JDIMENSION output_col);
118		EXTERN(void) _jpeg_idct_5x5(j_decompress_ptr cinfo,
119		jpeg_component_info *compptr, JCOEFPTR coef_block,
120		_JSAMPARRAY output_buf, JDIMENSION output_col);
121		EXTERN(void) _jpeg_idct_4x4(j_decompress_ptr cinfo,
122		jpeg_component_info *compptr, JCOEFPTR coef_block,
123		_JSAMPARRAY output_buf, JDIMENSION output_col);
124		EXTERN(void) _jpeg_idct_3x3(j_decompress_ptr cinfo,
125		jpeg_component_info *compptr, JCOEFPTR coef_block,
126		_JSAMPARRAY output_buf, JDIMENSION output_col);
127		EXTERN(void) _jpeg_idct_2x2(j_decompress_ptr cinfo,
128		jpeg_component_info *compptr, JCOEFPTR coef_block,
129		_JSAMPARRAY output_buf, JDIMENSION output_col);
130		EXTERN(void) _jpeg_idct_1x1(j_decompress_ptr cinfo,
131		jpeg_component_info *compptr, JCOEFPTR coef_block,
132		_JSAMPARRAY output_buf, JDIMENSION output_col);
133		EXTERN(void) _jpeg_idct_9x9(j_decompress_ptr cinfo,
134		jpeg_component_info *compptr, JCOEFPTR coef_block,
135		_JSAMPARRAY output_buf, JDIMENSION output_col);
136		EXTERN(void) _jpeg_idct_10x10(j_decompress_ptr cinfo,
137		jpeg_component_info *compptr,
138		JCOEFPTR coef_block, _JSAMPARRAY output_buf,
139		JDIMENSION output_col);
140		EXTERN(void) _jpeg_idct_11x11(j_decompress_ptr cinfo,
141		jpeg_component_info *compptr,
142		JCOEFPTR coef_block, _JSAMPARRAY output_buf,
143		JDIMENSION output_col);
144		EXTERN(void) _jpeg_idct_12x12(j_decompress_ptr cinfo,
145		jpeg_component_info *compptr,
146		JCOEFPTR coef_block, _JSAMPARRAY output_buf,
147		JDIMENSION output_col);
148		EXTERN(void) _jpeg_idct_13x13(j_decompress_ptr cinfo,
149		jpeg_component_info *compptr,
150		JCOEFPTR coef_block, _JSAMPARRAY output_buf,
151		JDIMENSION output_col);
152		EXTERN(void) _jpeg_idct_14x14(j_decompress_ptr cinfo,
153		jpeg_component_info *compptr,
154		JCOEFPTR coef_block, _JSAMPARRAY output_buf,
155		JDIMENSION output_col);
156		EXTERN(void) _jpeg_idct_15x15(j_decompress_ptr cinfo,
157		jpeg_component_info *compptr,
158		JCOEFPTR coef_block, _JSAMPARRAY output_buf,
159		JDIMENSION output_col);
160		EXTERN(void) _jpeg_idct_16x16(j_decompress_ptr cinfo,
161		jpeg_component_info *compptr,
162		JCOEFPTR coef_block, _JSAMPARRAY output_buf,
163		JDIMENSION output_col);
164
165
166		/*
167		* Macros for handling fixed-point arithmetic; these are used by many
168		* but not all of the DCT/IDCT modules.
169		*
170		* All values are expected to be of type JLONG.
171		* Fractional constants are scaled left by CONST_BITS bits.
172		* CONST_BITS is defined within each module using these macros,
173		* and may differ from one module to the next.
174		*/
175
176	0	#define ONE ((JLONG)1)
177		#define CONST_SCALE (ONE << CONST_BITS)
178
179		/* Convert a positive real constant to an integer scaled by CONST_SCALE.
180		* Caution: some C compilers fail to reduce "FIX(constant)" at compile time,
181		* thus causing a lot of useless floating-point operations at run time.
182		*/
183
184		#define FIX(x) ((JLONG)((x) * CONST_SCALE + 0.5))
185
186		/* Descale and correctly round a JLONG value that's scaled by N bits.
187		* We assume RIGHT_SHIFT rounds towards minus infinity, so adding
188		* the fudge factor is correct for either sign of X.
189		*/
190
191	676M	#define DESCALE(x, n) RIGHT_SHIFT((x) + (ONE << ((n) - 1)), n)
192
193		/* Multiply a JLONG variable by a JLONG constant to yield a JLONG result.
194		* This macro is used only when the two inputs will actually be no more than
195		* 16 bits wide, so that a 16x16->32 bit multiply can be used instead of a
196		* full 32x32 multiply. This provides a useful speedup on many machines.
197		* Unfortunately there is no way to specify a 16x16->32 multiply portably
198		* in C, but some C compilers will do the right thing if you provide the
199		* correct combination of casts.
200		*/
201
202		#ifdef SHORTxSHORT_32 /* may work if 'int' is 32 bits */
203		#define MULTIPLY16C16(var, const) (((INT16)(var)) * ((INT16)(const)))
204		#endif
205		#ifdef SHORTxLCONST_32 /* known to work with Microsoft C 6.0 */
206		#define MULTIPLY16C16(var, const) (((INT16)(var)) * ((JLONG)(const)))
207		#endif
208
209		#ifndef MULTIPLY16C16 /* default definition */
210	0	#define MULTIPLY16C16(var, const) ((var) * (const))
211		#endif
212
213		/* Same except both inputs are variables. */
214
215		#ifdef SHORTxSHORT_32 /* may work if 'int' is 32 bits */
216		#define MULTIPLY16V16(var1, var2) (((INT16)(var1)) * ((INT16)(var2)))
217		#endif
218
219		#ifndef MULTIPLY16V16 /* default definition */
220		#define MULTIPLY16V16(var1, var2) ((var1) * (var2))
221		#endif