4
* Copyright (C) 1994-1996, Thomas G. Lane.
5
* This file is part of the Independent JPEG Group's software.
6
* For conditions of distribution and use, see the accompanying README file.
8
* This include file contains common declarations for the forward and
9
* inverse DCT modules. These declarations are private to the DCT managers
10
* (jcdctmgr.c, jddctmgr.c) and the individual DCT algorithms.
11
* The individual DCT algorithms are kept in separate files to ease
12
* machine-dependent tuning (e.g., assembly coding).
17
* A forward DCT routine is given a pointer to an input sample array and
18
* a pointer to a work area of type DCTELEM[]; the DCT is to be performed
19
* in-place in that buffer. Type DCTELEM is int for 8-bit samples, INT32
20
* for 12-bit samples. (NOTE: Floating-point DCT implementations use an
21
* array of type FAST_FLOAT, instead.)
22
* The input data is to be fetched from the sample array starting at a
23
* specified column. (Any row offset needed will be applied to the array
24
* pointer before it is passed to the FDCT code.)
25
* Note that the number of samples fetched by the FDCT routine is
26
* DCT_h_scaled_size * DCT_v_scaled_size.
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.
34
#if BITS_IN_JSAMPLE == 8
35
typedef int DCTELEM; /* 16 or 32 bits is fine */
37
typedef INT32 DCTELEM; /* must have 32 bits */
40
typedef JMETHOD(void, forward_DCT_method_ptr, (DCTELEM * data,
41
JSAMPARRAY sample_data,
42
JDIMENSION start_col));
43
typedef JMETHOD(void, float_DCT_method_ptr, (FAST_FLOAT * data,
44
JSAMPARRAY sample_data,
45
JDIMENSION start_col));
49
* An inverse DCT routine is given a pointer to the input JBLOCK and a pointer
50
* to an output sample array. The routine must dequantize the input data as
51
* well as perform the IDCT; for dequantization, it uses the multiplier table
52
* pointed to by compptr->dct_table. The output data is to be placed into the
53
* sample array starting at a specified column. (Any row offset needed will
54
* be applied to the array pointer before it is passed to the IDCT code.)
55
* Note that the number of samples emitted by the IDCT routine is
56
* DCT_h_scaled_size * DCT_v_scaled_size.
59
/* typedef inverse_DCT_method_ptr is declared in jpegint.h */
62
* Each IDCT routine has its own ideas about the best dct_table element type.
65
typedef MULTIPLIER ISLOW_MULT_TYPE; /* short or int, whichever is faster */
66
#if BITS_IN_JSAMPLE == 8
67
typedef MULTIPLIER IFAST_MULT_TYPE; /* 16 bits is OK, use short if faster */
68
#define IFAST_SCALE_BITS 2 /* fractional bits in scale factors */
70
typedef INT32 IFAST_MULT_TYPE; /* need 32 bits for scaled quantizers */
71
#define IFAST_SCALE_BITS 13 /* fractional bits in scale factors */
73
typedef FAST_FLOAT FLOAT_MULT_TYPE; /* preferred floating type */
77
* Each IDCT routine is responsible for range-limiting its results and
78
* converting them to unsigned form (0..MAXJSAMPLE). The raw outputs could
79
* be quite far out of range if the input data is corrupt, so a bulletproof
80
* range-limiting step is required. We use a mask-and-table-lookup method
81
* to do the combined operations quickly. See the comments with
82
* prepare_range_limit_table (in jdmaster.c) for more info.
85
#define IDCT_range_limit(cinfo) ((cinfo)->sample_range_limit + CENTERJSAMPLE)
87
#define RANGE_MASK (MAXJSAMPLE * 4 + 3) /* 2 bits wider than legal samples */
90
/* Short forms of external names for systems with brain-damaged linkers. */
92
#ifdef NEED_SHORT_EXTERNAL_NAMES
93
#define jpeg_fdct_islow jFDislow
94
#define jpeg_fdct_ifast jFDifast
95
#define jpeg_fdct_float jFDfloat
96
#define jpeg_fdct_7x7 jFD7x7
97
#define jpeg_fdct_6x6 jFD6x6
98
#define jpeg_fdct_5x5 jFD5x5
99
#define jpeg_fdct_4x4 jFD4x4
100
#define jpeg_fdct_3x3 jFD3x3
101
#define jpeg_fdct_2x2 jFD2x2
102
#define jpeg_fdct_1x1 jFD1x1
103
#define jpeg_fdct_9x9 jFD9x9
104
#define jpeg_fdct_10x10 jFD10x10
105
#define jpeg_fdct_11x11 jFD11x11
106
#define jpeg_fdct_12x12 jFD12x12
107
#define jpeg_fdct_13x13 jFD13x13
108
#define jpeg_fdct_14x14 jFD14x14
109
#define jpeg_fdct_15x15 jFD15x15
110
#define jpeg_fdct_16x16 jFD16x16
111
#define jpeg_fdct_16x8 jFD16x8
112
#define jpeg_fdct_14x7 jFD14x7
113
#define jpeg_fdct_12x6 jFD12x6
114
#define jpeg_fdct_10x5 jFD10x5
115
#define jpeg_fdct_8x4 jFD8x4
116
#define jpeg_fdct_6x3 jFD6x3
117
#define jpeg_fdct_4x2 jFD4x2
118
#define jpeg_fdct_2x1 jFD2x1
119
#define jpeg_fdct_8x16 jFD8x16
120
#define jpeg_fdct_7x14 jFD7x14
121
#define jpeg_fdct_6x12 jFD6x12
122
#define jpeg_fdct_5x10 jFD5x10
123
#define jpeg_fdct_4x8 jFD4x8
124
#define jpeg_fdct_3x6 jFD3x6
125
#define jpeg_fdct_2x4 jFD2x4
126
#define jpeg_fdct_1x2 jFD1x2
127
#define jpeg_idct_islow jRDislow
128
#define jpeg_idct_ifast jRDifast
129
#define jpeg_idct_float jRDfloat
130
#define jpeg_idct_7x7 jRD7x7
131
#define jpeg_idct_6x6 jRD6x6
132
#define jpeg_idct_5x5 jRD5x5
133
#define jpeg_idct_4x4 jRD4x4
134
#define jpeg_idct_3x3 jRD3x3
135
#define jpeg_idct_2x2 jRD2x2
136
#define jpeg_idct_1x1 jRD1x1
137
#define jpeg_idct_9x9 jRD9x9
138
#define jpeg_idct_10x10 jRD10x10
139
#define jpeg_idct_11x11 jRD11x11
140
#define jpeg_idct_12x12 jRD12x12
141
#define jpeg_idct_13x13 jRD13x13
142
#define jpeg_idct_14x14 jRD14x14
143
#define jpeg_idct_15x15 jRD15x15
144
#define jpeg_idct_16x16 jRD16x16
145
#define jpeg_idct_16x8 jRD16x8
146
#define jpeg_idct_14x7 jRD14x7
147
#define jpeg_idct_12x6 jRD12x6
148
#define jpeg_idct_10x5 jRD10x5
149
#define jpeg_idct_8x4 jRD8x4
150
#define jpeg_idct_6x3 jRD6x3
151
#define jpeg_idct_4x2 jRD4x2
152
#define jpeg_idct_2x1 jRD2x1
153
#define jpeg_idct_8x16 jRD8x16
154
#define jpeg_idct_7x14 jRD7x14
155
#define jpeg_idct_6x12 jRD6x12
156
#define jpeg_idct_5x10 jRD5x10
157
#define jpeg_idct_4x8 jRD4x8
158
#define jpeg_idct_3x6 jRD3x8
159
#define jpeg_idct_2x4 jRD2x4
160
#define jpeg_idct_1x2 jRD1x2
161
#endif /* NEED_SHORT_EXTERNAL_NAMES */
163
/* Extern declarations for the forward and inverse DCT routines. */
165
EXTERN(void) jpeg_fdct_islow
166
JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
167
EXTERN(void) jpeg_fdct_ifast
168
JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
169
EXTERN(void) jpeg_fdct_float
170
JPP((FAST_FLOAT * data, JSAMPARRAY sample_data, JDIMENSION start_col));
171
EXTERN(void) jpeg_fdct_7x7
172
JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
173
EXTERN(void) jpeg_fdct_6x6
174
JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
175
EXTERN(void) jpeg_fdct_5x5
176
JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
177
EXTERN(void) jpeg_fdct_4x4
178
JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
179
EXTERN(void) jpeg_fdct_3x3
180
JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
181
EXTERN(void) jpeg_fdct_2x2
182
JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
183
EXTERN(void) jpeg_fdct_1x1
184
JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
185
EXTERN(void) jpeg_fdct_9x9
186
JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
187
EXTERN(void) jpeg_fdct_10x10
188
JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
189
EXTERN(void) jpeg_fdct_11x11
190
JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
191
EXTERN(void) jpeg_fdct_12x12
192
JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
193
EXTERN(void) jpeg_fdct_13x13
194
JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
195
EXTERN(void) jpeg_fdct_14x14
196
JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
197
EXTERN(void) jpeg_fdct_15x15
198
JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
199
EXTERN(void) jpeg_fdct_16x16
200
JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
201
EXTERN(void) jpeg_fdct_16x8
202
JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
203
EXTERN(void) jpeg_fdct_14x7
204
JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
205
EXTERN(void) jpeg_fdct_12x6
206
JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
207
EXTERN(void) jpeg_fdct_10x5
208
JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
209
EXTERN(void) jpeg_fdct_8x4
210
JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
211
EXTERN(void) jpeg_fdct_6x3
212
JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
213
EXTERN(void) jpeg_fdct_4x2
214
JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
215
EXTERN(void) jpeg_fdct_2x1
216
JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
217
EXTERN(void) jpeg_fdct_8x16
218
JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
219
EXTERN(void) jpeg_fdct_7x14
220
JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
221
EXTERN(void) jpeg_fdct_6x12
222
JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
223
EXTERN(void) jpeg_fdct_5x10
224
JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
225
EXTERN(void) jpeg_fdct_4x8
226
JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
227
EXTERN(void) jpeg_fdct_3x6
228
JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
229
EXTERN(void) jpeg_fdct_2x4
230
JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
231
EXTERN(void) jpeg_fdct_1x2
232
JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
234
EXTERN(void) jpeg_idct_islow
235
JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
236
JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
237
EXTERN(void) jpeg_idct_ifast
238
JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
239
JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
240
EXTERN(void) jpeg_idct_float
241
JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
242
JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
243
EXTERN(void) jpeg_idct_7x7
244
JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
245
JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
246
EXTERN(void) jpeg_idct_6x6
247
JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
248
JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
249
EXTERN(void) jpeg_idct_5x5
250
JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
251
JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
252
EXTERN(void) jpeg_idct_4x4
253
JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
254
JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
255
EXTERN(void) jpeg_idct_3x3
256
JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
257
JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
258
EXTERN(void) jpeg_idct_2x2
259
JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
260
JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
261
EXTERN(void) jpeg_idct_1x1
262
JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
263
JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
264
EXTERN(void) jpeg_idct_9x9
265
JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
266
JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
267
EXTERN(void) jpeg_idct_10x10
268
JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
269
JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
270
EXTERN(void) jpeg_idct_11x11
271
JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
272
JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
273
EXTERN(void) jpeg_idct_12x12
274
JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
275
JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
276
EXTERN(void) jpeg_idct_13x13
277
JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
278
JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
279
EXTERN(void) jpeg_idct_14x14
280
JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
281
JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
282
EXTERN(void) jpeg_idct_15x15
283
JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
284
JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
285
EXTERN(void) jpeg_idct_16x16
286
JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
287
JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
288
EXTERN(void) jpeg_idct_16x8
289
JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
290
JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
291
EXTERN(void) jpeg_idct_14x7
292
JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
293
JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
294
EXTERN(void) jpeg_idct_12x6
295
JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
296
JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
297
EXTERN(void) jpeg_idct_10x5
298
JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
299
JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
300
EXTERN(void) jpeg_idct_8x4
301
JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
302
JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
303
EXTERN(void) jpeg_idct_6x3
304
JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
305
JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
306
EXTERN(void) jpeg_idct_4x2
307
JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
308
JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
309
EXTERN(void) jpeg_idct_2x1
310
JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
311
JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
312
EXTERN(void) jpeg_idct_8x16
313
JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
314
JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
315
EXTERN(void) jpeg_idct_7x14
316
JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
317
JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
318
EXTERN(void) jpeg_idct_6x12
319
JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
320
JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
321
EXTERN(void) jpeg_idct_5x10
322
JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
323
JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
324
EXTERN(void) jpeg_idct_4x8
325
JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
326
JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
327
EXTERN(void) jpeg_idct_3x6
328
JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
329
JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
330
EXTERN(void) jpeg_idct_2x4
331
JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
332
JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
333
EXTERN(void) jpeg_idct_1x2
334
JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
335
JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
339
* Macros for handling fixed-point arithmetic; these are used by many
340
* but not all of the DCT/IDCT modules.
342
* All values are expected to be of type INT32.
343
* Fractional constants are scaled left by CONST_BITS bits.
344
* CONST_BITS is defined within each module using these macros,
345
* and may differ from one module to the next.
348
#define ONE ((INT32) 1)
349
#define CONST_SCALE (ONE << CONST_BITS)
351
/* Convert a positive real constant to an integer scaled by CONST_SCALE.
352
* Caution: some C compilers fail to reduce "FIX(constant)" at compile time,
353
* thus causing a lot of useless floating-point operations at run time.
356
#define FIX(x) ((INT32) ((x) * CONST_SCALE + 0.5))
358
/* Descale and correctly round an INT32 value that's scaled by N bits.
359
* We assume RIGHT_SHIFT rounds towards minus infinity, so adding
360
* the fudge factor is correct for either sign of X.
363
#define DESCALE(x,n) RIGHT_SHIFT((x) + (ONE << ((n)-1)), n)
365
/* Multiply an INT32 variable by an INT32 constant to yield an INT32 result.
366
* This macro is used only when the two inputs will actually be no more than
367
* 16 bits wide, so that a 16x16->32 bit multiply can be used instead of a
368
* full 32x32 multiply. This provides a useful speedup on many machines.
369
* Unfortunately there is no way to specify a 16x16->32 multiply portably
370
* in C, but some C compilers will do the right thing if you provide the
371
* correct combination of casts.
374
#ifdef SHORTxSHORT_32 /* may work if 'int' is 32 bits */
375
#define MULTIPLY16C16(var,const) (((INT16) (var)) * ((INT16) (const)))
377
#ifdef SHORTxLCONST_32 /* known to work with Microsoft C 6.0 */
378
#define MULTIPLY16C16(var,const) (((INT16) (var)) * ((INT32) (const)))
381
#ifndef MULTIPLY16C16 /* default definition */
382
#define MULTIPLY16C16(var,const) ((var) * (const))
385
/* Same except both inputs are variables. */
387
#ifdef SHORTxSHORT_32 /* may work if 'int' is 32 bits */
388
#define MULTIPLY16V16(var1,var2) (((INT16) (var1)) * ((INT16) (var2)))
391
#ifndef MULTIPLY16V16 /* default definition */
392
#define MULTIPLY16V16(var1,var2) ((var1) * (var2))
added
removed
jpg/jdct.h
