ReactOS  0.4.13-dev-687-g023794c
jdct.h
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1 /*
2  * jdct.h
3  *
4  * Copyright (C) 1994-1996, Thomas G. Lane.
5  * Modified 2002-2017 by Guido Vollbeding.
6  * This file is part of the Independent JPEG Group's software.
7  * For conditions of distribution and use, see the accompanying README file.
8  *
9  * This include file contains common declarations for the forward and
10  * inverse DCT modules. These declarations are private to the DCT managers
11  * (jcdctmgr.c, jddctmgr.c) and the individual DCT algorithms.
12  * The individual DCT algorithms are kept in separate files to ease
13  * machine-dependent tuning (e.g., assembly coding).
14  */
15 
16 
17 /*
18  * A forward DCT routine is given a pointer to an input sample array and
19  * a pointer to a work area of type DCTELEM[]; the DCT is to be performed
20  * in-place in that buffer. Type DCTELEM is int for 8-bit samples, INT32
21  * for 12-bit samples. (NOTE: Floating-point DCT implementations use an
22  * array of type FAST_FLOAT, instead.)
23  * The input data is to be fetched from the sample array starting at a
24  * specified column. (Any row offset needed will be applied to the array
25  * pointer before it is passed to the FDCT code.)
26  * Note that the number of samples fetched by the FDCT routine is
27  * DCT_h_scaled_size * DCT_v_scaled_size.
28  * The DCT outputs are returned scaled up by a factor of 8; they therefore
29  * have a range of +-8K for 8-bit data, +-128K for 12-bit data. This
30  * convention improves accuracy in integer implementations and saves some
31  * work in floating-point ones.
32  * Quantization of the output coefficients is done by jcdctmgr.c.
33  */
34 
35 #if BITS_IN_JSAMPLE == 8
36 typedef int DCTELEM; /* 16 or 32 bits is fine */
37 #else
38 typedef INT32 DCTELEM; /* must have 32 bits */
39 #endif
40 
41 typedef JMETHOD(void, forward_DCT_method_ptr, (DCTELEM * data,
44 typedef JMETHOD(void, float_DCT_method_ptr, (FAST_FLOAT * data,
47 
48 
49 /*
50  * An inverse DCT routine is given a pointer to the input JBLOCK and a pointer
51  * to an output sample array. The routine must dequantize the input data as
52  * well as perform the IDCT; for dequantization, it uses the multiplier table
53  * pointed to by compptr->dct_table. The output data is to be placed into the
54  * sample array starting at a specified column. (Any row offset needed will
55  * be applied to the array pointer before it is passed to the IDCT code.)
56  * Note that the number of samples emitted by the IDCT routine is
57  * DCT_h_scaled_size * DCT_v_scaled_size.
58  */
59 
60 /* typedef inverse_DCT_method_ptr is declared in jpegint.h */
61 
62 /*
63  * Each IDCT routine has its own ideas about the best dct_table element type.
64  */
65 
66 typedef MULTIPLIER ISLOW_MULT_TYPE; /* short or int, whichever is faster */
67 #if BITS_IN_JSAMPLE == 8
68 typedef MULTIPLIER IFAST_MULT_TYPE; /* 16 bits is OK, use short if faster */
69 #define IFAST_SCALE_BITS 2 /* fractional bits in scale factors */
70 #else
71 typedef INT32 IFAST_MULT_TYPE; /* need 32 bits for scaled quantizers */
72 #define IFAST_SCALE_BITS 13 /* fractional bits in scale factors */
73 #endif
74 typedef FAST_FLOAT FLOAT_MULT_TYPE; /* preferred floating type */
75 
76 
77 /*
78  * Each IDCT routine is responsible for range-limiting its results and
79  * converting them to unsigned form (0..MAXJSAMPLE). The raw outputs could
80  * be quite far out of range if the input data is corrupt, so a bulletproof
81  * range-limiting step is required. We use a mask-and-table-lookup method
82  * to do the combined operations quickly, assuming that RANGE_CENTER
83  * (defined in jpegint.h) is a power of 2. See the comments with
84  * prepare_range_limit_table (in jdmaster.c) for more info.
85  */
86 
87 #define RANGE_MASK (RANGE_CENTER * 2 - 1)
88 #define RANGE_SUBSET (RANGE_CENTER - CENTERJSAMPLE)
89 
90 #define IDCT_range_limit(cinfo) ((cinfo)->sample_range_limit - RANGE_SUBSET)
91 
92 
93 /* Short forms of external names for systems with brain-damaged linkers. */
94 
95 #ifdef NEED_SHORT_EXTERNAL_NAMES
96 #define jpeg_fdct_islow jFDislow
97 #define jpeg_fdct_ifast jFDifast
98 #define jpeg_fdct_float jFDfloat
99 #define jpeg_fdct_7x7 jFD7x7
100 #define jpeg_fdct_6x6 jFD6x6
101 #define jpeg_fdct_5x5 jFD5x5
102 #define jpeg_fdct_4x4 jFD4x4
103 #define jpeg_fdct_3x3 jFD3x3
104 #define jpeg_fdct_2x2 jFD2x2
105 #define jpeg_fdct_1x1 jFD1x1
106 #define jpeg_fdct_9x9 jFD9x9
107 #define jpeg_fdct_10x10 jFD10x10
108 #define jpeg_fdct_11x11 jFD11x11
109 #define jpeg_fdct_12x12 jFD12x12
110 #define jpeg_fdct_13x13 jFD13x13
111 #define jpeg_fdct_14x14 jFD14x14
112 #define jpeg_fdct_15x15 jFD15x15
113 #define jpeg_fdct_16x16 jFD16x16
114 #define jpeg_fdct_16x8 jFD16x8
115 #define jpeg_fdct_14x7 jFD14x7
116 #define jpeg_fdct_12x6 jFD12x6
117 #define jpeg_fdct_10x5 jFD10x5
118 #define jpeg_fdct_8x4 jFD8x4
119 #define jpeg_fdct_6x3 jFD6x3
120 #define jpeg_fdct_4x2 jFD4x2
121 #define jpeg_fdct_2x1 jFD2x1
122 #define jpeg_fdct_8x16 jFD8x16
123 #define jpeg_fdct_7x14 jFD7x14
124 #define jpeg_fdct_6x12 jFD6x12
125 #define jpeg_fdct_5x10 jFD5x10
126 #define jpeg_fdct_4x8 jFD4x8
127 #define jpeg_fdct_3x6 jFD3x6
128 #define jpeg_fdct_2x4 jFD2x4
129 #define jpeg_fdct_1x2 jFD1x2
130 #define jpeg_idct_islow jRDislow
131 #define jpeg_idct_ifast jRDifast
132 #define jpeg_idct_float jRDfloat
133 #define jpeg_idct_7x7 jRD7x7
134 #define jpeg_idct_6x6 jRD6x6
135 #define jpeg_idct_5x5 jRD5x5
136 #define jpeg_idct_4x4 jRD4x4
137 #define jpeg_idct_3x3 jRD3x3
138 #define jpeg_idct_2x2 jRD2x2
139 #define jpeg_idct_1x1 jRD1x1
140 #define jpeg_idct_9x9 jRD9x9
141 #define jpeg_idct_10x10 jRD10x10
142 #define jpeg_idct_11x11 jRD11x11
143 #define jpeg_idct_12x12 jRD12x12
144 #define jpeg_idct_13x13 jRD13x13
145 #define jpeg_idct_14x14 jRD14x14
146 #define jpeg_idct_15x15 jRD15x15
147 #define jpeg_idct_16x16 jRD16x16
148 #define jpeg_idct_16x8 jRD16x8
149 #define jpeg_idct_14x7 jRD14x7
150 #define jpeg_idct_12x6 jRD12x6
151 #define jpeg_idct_10x5 jRD10x5
152 #define jpeg_idct_8x4 jRD8x4
153 #define jpeg_idct_6x3 jRD6x3
154 #define jpeg_idct_4x2 jRD4x2
155 #define jpeg_idct_2x1 jRD2x1
156 #define jpeg_idct_8x16 jRD8x16
157 #define jpeg_idct_7x14 jRD7x14
158 #define jpeg_idct_6x12 jRD6x12
159 #define jpeg_idct_5x10 jRD5x10
160 #define jpeg_idct_4x8 jRD4x8
161 #define jpeg_idct_3x6 jRD3x8
162 #define jpeg_idct_2x4 jRD2x4
163 #define jpeg_idct_1x2 jRD1x2
164 #endif /* NEED_SHORT_EXTERNAL_NAMES */
165 
166 /* Extern declarations for the forward and inverse DCT routines. */
167 
168 EXTERN(void) jpeg_fdct_islow
170 EXTERN(void) jpeg_fdct_ifast
172 EXTERN(void) jpeg_fdct_float
174 EXTERN(void) jpeg_fdct_7x7
176 EXTERN(void) jpeg_fdct_6x6
178 EXTERN(void) jpeg_fdct_5x5
180 EXTERN(void) jpeg_fdct_4x4
182 EXTERN(void) jpeg_fdct_3x3
184 EXTERN(void) jpeg_fdct_2x2
186 EXTERN(void) jpeg_fdct_1x1
188 EXTERN(void) jpeg_fdct_9x9
190 EXTERN(void) jpeg_fdct_10x10
192 EXTERN(void) jpeg_fdct_11x11
194 EXTERN(void) jpeg_fdct_12x12
196 EXTERN(void) jpeg_fdct_13x13
198 EXTERN(void) jpeg_fdct_14x14
200 EXTERN(void) jpeg_fdct_15x15
202 EXTERN(void) jpeg_fdct_16x16
204 EXTERN(void) jpeg_fdct_16x8
206 EXTERN(void) jpeg_fdct_14x7
208 EXTERN(void) jpeg_fdct_12x6
210 EXTERN(void) jpeg_fdct_10x5
212 EXTERN(void) jpeg_fdct_8x4
214 EXTERN(void) jpeg_fdct_6x3
216 EXTERN(void) jpeg_fdct_4x2
218 EXTERN(void) jpeg_fdct_2x1
220 EXTERN(void) jpeg_fdct_8x16
222 EXTERN(void) jpeg_fdct_7x14
224 EXTERN(void) jpeg_fdct_6x12
226 EXTERN(void) jpeg_fdct_5x10
228 EXTERN(void) jpeg_fdct_4x8
230 EXTERN(void) jpeg_fdct_3x6
232 EXTERN(void) jpeg_fdct_2x4
234 EXTERN(void) jpeg_fdct_1x2
236 
237 EXTERN(void) jpeg_idct_islow
240 EXTERN(void) jpeg_idct_ifast
243 EXTERN(void) jpeg_idct_float
246 EXTERN(void) jpeg_idct_7x7
249 EXTERN(void) jpeg_idct_6x6
252 EXTERN(void) jpeg_idct_5x5
255 EXTERN(void) jpeg_idct_4x4
258 EXTERN(void) jpeg_idct_3x3
261 EXTERN(void) jpeg_idct_2x2
264 EXTERN(void) jpeg_idct_1x1
267 EXTERN(void) jpeg_idct_9x9
270 EXTERN(void) jpeg_idct_10x10
273 EXTERN(void) jpeg_idct_11x11
276 EXTERN(void) jpeg_idct_12x12
279 EXTERN(void) jpeg_idct_13x13
282 EXTERN(void) jpeg_idct_14x14
285 EXTERN(void) jpeg_idct_15x15
288 EXTERN(void) jpeg_idct_16x16
291 EXTERN(void) jpeg_idct_16x8
294 EXTERN(void) jpeg_idct_14x7
297 EXTERN(void) jpeg_idct_12x6
300 EXTERN(void) jpeg_idct_10x5
303 EXTERN(void) jpeg_idct_8x4
306 EXTERN(void) jpeg_idct_6x3
309 EXTERN(void) jpeg_idct_4x2
312 EXTERN(void) jpeg_idct_2x1
315 EXTERN(void) jpeg_idct_8x16
318 EXTERN(void) jpeg_idct_7x14
321 EXTERN(void) jpeg_idct_6x12
324 EXTERN(void) jpeg_idct_5x10
327 EXTERN(void) jpeg_idct_4x8
330 EXTERN(void) jpeg_idct_3x6
333 EXTERN(void) jpeg_idct_2x4
336 EXTERN(void) jpeg_idct_1x2
339 
340 
341 /*
342  * Macros for handling fixed-point arithmetic; these are used by many
343  * but not all of the DCT/IDCT modules.
344  *
345  * All values are expected to be of type INT32.
346  * Fractional constants are scaled left by CONST_BITS bits.
347  * CONST_BITS is defined within each module using these macros,
348  * and may differ from one module to the next.
349  */
350 
351 #define ONE ((INT32) 1)
352 #define CONST_SCALE (ONE << CONST_BITS)
353 
354 /* Convert a positive real constant to an integer scaled by CONST_SCALE.
355  * Caution: some C compilers fail to reduce "FIX(constant)" at compile time,
356  * thus causing a lot of useless floating-point operations at run time.
357  */
358 
359 #define FIX(x) ((INT32) ((x) * CONST_SCALE + 0.5))
360 
361 /* Descale and correctly round an INT32 value that's scaled by N bits.
362  * We assume RIGHT_SHIFT rounds towards minus infinity, so adding
363  * the fudge factor is correct for either sign of X.
364  */
365 
366 #define DESCALE(x,n) RIGHT_SHIFT((x) + (ONE << ((n)-1)), n)
367 
368 /* Multiply an INT32 variable by an INT32 constant to yield an INT32 result.
369  * This macro is used only when the two inputs will actually be no more than
370  * 16 bits wide, so that a 16x16->32 bit multiply can be used instead of a
371  * full 32x32 multiply. This provides a useful speedup on many machines.
372  * Unfortunately there is no way to specify a 16x16->32 multiply portably
373  * in C, but some C compilers will do the right thing if you provide the
374  * correct combination of casts.
375  */
376 
377 #ifdef SHORTxSHORT_32 /* may work if 'int' is 32 bits */
378 #define MULTIPLY16C16(var,const) (((INT16) (var)) * ((INT16) (const)))
379 #endif
380 #ifdef SHORTxLCONST_32 /* known to work with Microsoft C 6.0 */
381 #define MULTIPLY16C16(var,const) (((INT16) (var)) * ((INT32) (const)))
382 #endif
383 
384 #ifndef MULTIPLY16C16 /* default definition */
385 #define MULTIPLY16C16(var,const) ((var) * (const))
386 #endif
387 
388 /* Same except both inputs are variables. */
389 
390 #ifdef SHORTxSHORT_32 /* may work if 'int' is 32 bits */
391 #define MULTIPLY16V16(var1,var2) (((INT16) (var1)) * ((INT16) (var2)))
392 #endif
393 
394 #ifndef MULTIPLY16V16 /* default definition */
395 #define MULTIPLY16V16(var1,var2) ((var1) * (var2))
396 #endif
397 
398 /* Like RIGHT_SHIFT, but applies to a DCTELEM.
399  * We assume that int right shift is unsigned if INT32 right shift is.
400  */
401 
402 #ifdef RIGHT_SHIFT_IS_UNSIGNED
403 #define ISHIFT_TEMPS DCTELEM ishift_temp;
404 #if BITS_IN_JSAMPLE == 8
405 #define DCTELEMBITS 16 /* DCTELEM may be 16 or 32 bits */
406 #else
407 #define DCTELEMBITS 32 /* DCTELEM must be 32 bits */
408 #endif
409 #define IRIGHT_SHIFT(x,shft) \
410  ((ishift_temp = (x)) < 0 ? \
411  (ishift_temp >> (shft)) | ((~((DCTELEM) 0)) << (DCTELEMBITS-(shft))) : \
412  (ishift_temp >> (shft)))
413 #else
414 #define ISHIFT_TEMPS
415 #define IRIGHT_SHIFT(x,shft) ((x) >> (shft))
416 #endif
jpeg_component_info JCOEFPTR coef_block
Definition: jdct.h:238
JSAMPARRAY JDIMENSION start_col
Definition: jdct.h:169
INT32 DCTELEM
Definition: jdct.h:38
jpeg_component_info * compptr
Definition: jdct.h:238
typedef JMETHOD(void, forward_DCT_method_ptr,(DCTELEM *data, JSAMPARRAY sample_data, JDIMENSION start_col))
jpeg_component_info JCOEFPTR JSAMPARRAY JDIMENSION output_col
Definition: jdct.h:238
INT32 IFAST_MULT_TYPE
Definition: jdct.h:71
MULTIPLIER ISLOW_MULT_TYPE
Definition: jdct.h:66
JCOEF FAR * JCOEFPTR
Definition: jpeglib.h:84
GLint GLenum GLsizei GLsizei GLsizei GLint GLsizei const GLvoid * data
Definition: gl.h:1950
#define JPP(arglist)
Definition: jpeglib.h:877
FAST_FLOAT FLOAT_MULT_TYPE
Definition: jdct.h:74
JSAMPROW * JSAMPARRAY
Definition: jpeglib.h:76
jpeg_component_info JCOEFPTR JSAMPARRAY output_buf
Definition: jdct.h:238
unsigned int JDIMENSION
Definition: jmorecfg.h:229
signed int INT32
JSAMPARRAY sample_data
Definition: jdct.h:169
EXTERN(void) jpeg_fdct_islow JPP((DCTELEM *data