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/src/FreeImage/Source/LibJPEG/jdct.h

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C++ Header | 393 lines | 281 code | 32 blank | 80 comment | 2 complexity | 7719dc8cc3a8c3d138e65538fe9aac93 MD5 | raw file
  1/*
  2 * jdct.h
  3 *
  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.
  7 *
  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).
 13 */
 14
 15
 16/*
 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.
 32 */
 33
 34#if BITS_IN_JSAMPLE == 8
 35typedef int DCTELEM;		/* 16 or 32 bits is fine */
 36#else
 37typedef INT32 DCTELEM;		/* must have 32 bits */
 38#endif
 39
 40typedef JMETHOD(void, forward_DCT_method_ptr, (DCTELEM * data,
 41					       JSAMPARRAY sample_data,
 42					       JDIMENSION start_col));
 43typedef JMETHOD(void, float_DCT_method_ptr, (FAST_FLOAT * data,
 44					     JSAMPARRAY sample_data,
 45					     JDIMENSION start_col));
 46
 47
 48/*
 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.
 57 */
 58
 59/* typedef inverse_DCT_method_ptr is declared in jpegint.h */
 60
 61/*
 62 * Each IDCT routine has its own ideas about the best dct_table element type.
 63 */
 64
 65typedef MULTIPLIER ISLOW_MULT_TYPE; /* short or int, whichever is faster */
 66#if BITS_IN_JSAMPLE == 8
 67typedef MULTIPLIER IFAST_MULT_TYPE; /* 16 bits is OK, use short if faster */
 68#define IFAST_SCALE_BITS  2	/* fractional bits in scale factors */
 69#else
 70typedef INT32 IFAST_MULT_TYPE;	/* need 32 bits for scaled quantizers */
 71#define IFAST_SCALE_BITS  13	/* fractional bits in scale factors */
 72#endif
 73typedef FAST_FLOAT FLOAT_MULT_TYPE; /* preferred floating type */
 74
 75
 76/*
 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.
 83 */
 84
 85#define IDCT_range_limit(cinfo)  ((cinfo)->sample_range_limit + CENTERJSAMPLE)
 86
 87#define RANGE_MASK  (MAXJSAMPLE * 4 + 3) /* 2 bits wider than legal samples */
 88
 89
 90/* Short forms of external names for systems with brain-damaged linkers. */
 91
 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 */
162
163/* Extern declarations for the forward and inverse DCT routines. */
164
165EXTERN(void) jpeg_fdct_islow
166    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
167EXTERN(void) jpeg_fdct_ifast
168    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
169EXTERN(void) jpeg_fdct_float
170    JPP((FAST_FLOAT * data, JSAMPARRAY sample_data, JDIMENSION start_col));
171EXTERN(void) jpeg_fdct_7x7
172    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
173EXTERN(void) jpeg_fdct_6x6
174    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
175EXTERN(void) jpeg_fdct_5x5
176    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
177EXTERN(void) jpeg_fdct_4x4
178    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
179EXTERN(void) jpeg_fdct_3x3
180    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
181EXTERN(void) jpeg_fdct_2x2
182    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
183EXTERN(void) jpeg_fdct_1x1
184    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
185EXTERN(void) jpeg_fdct_9x9
186    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
187EXTERN(void) jpeg_fdct_10x10
188    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
189EXTERN(void) jpeg_fdct_11x11
190    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
191EXTERN(void) jpeg_fdct_12x12
192    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
193EXTERN(void) jpeg_fdct_13x13
194    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
195EXTERN(void) jpeg_fdct_14x14
196    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
197EXTERN(void) jpeg_fdct_15x15
198    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
199EXTERN(void) jpeg_fdct_16x16
200    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
201EXTERN(void) jpeg_fdct_16x8
202    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
203EXTERN(void) jpeg_fdct_14x7
204    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
205EXTERN(void) jpeg_fdct_12x6
206    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
207EXTERN(void) jpeg_fdct_10x5
208    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
209EXTERN(void) jpeg_fdct_8x4
210    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
211EXTERN(void) jpeg_fdct_6x3
212    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
213EXTERN(void) jpeg_fdct_4x2
214    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
215EXTERN(void) jpeg_fdct_2x1
216    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
217EXTERN(void) jpeg_fdct_8x16
218    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
219EXTERN(void) jpeg_fdct_7x14
220    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
221EXTERN(void) jpeg_fdct_6x12
222    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
223EXTERN(void) jpeg_fdct_5x10
224    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
225EXTERN(void) jpeg_fdct_4x8
226    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
227EXTERN(void) jpeg_fdct_3x6
228    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
229EXTERN(void) jpeg_fdct_2x4
230    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
231EXTERN(void) jpeg_fdct_1x2
232    JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
233
234EXTERN(void) jpeg_idct_islow
235    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
236	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
237EXTERN(void) jpeg_idct_ifast
238    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
239	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
240EXTERN(void) jpeg_idct_float
241    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
242	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
243EXTERN(void) jpeg_idct_7x7
244    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
245	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
246EXTERN(void) jpeg_idct_6x6
247    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
248	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
249EXTERN(void) jpeg_idct_5x5
250    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
251	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
252EXTERN(void) jpeg_idct_4x4
253    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
254	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
255EXTERN(void) jpeg_idct_3x3
256    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
257	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
258EXTERN(void) jpeg_idct_2x2
259    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
260	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
261EXTERN(void) jpeg_idct_1x1
262    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
263	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
264EXTERN(void) jpeg_idct_9x9
265    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
266	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
267EXTERN(void) jpeg_idct_10x10
268    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
269	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
270EXTERN(void) jpeg_idct_11x11
271    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
272	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
273EXTERN(void) jpeg_idct_12x12
274    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
275	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
276EXTERN(void) jpeg_idct_13x13
277    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
278	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
279EXTERN(void) jpeg_idct_14x14
280    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
281	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
282EXTERN(void) jpeg_idct_15x15
283    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
284	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
285EXTERN(void) jpeg_idct_16x16
286    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
287	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
288EXTERN(void) jpeg_idct_16x8
289    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
290	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
291EXTERN(void) jpeg_idct_14x7
292    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
293	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
294EXTERN(void) jpeg_idct_12x6
295    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
296	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
297EXTERN(void) jpeg_idct_10x5
298    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
299	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
300EXTERN(void) jpeg_idct_8x4
301    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
302	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
303EXTERN(void) jpeg_idct_6x3
304    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
305	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
306EXTERN(void) jpeg_idct_4x2
307    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
308	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
309EXTERN(void) jpeg_idct_2x1
310    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
311	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
312EXTERN(void) jpeg_idct_8x16
313    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
314	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
315EXTERN(void) jpeg_idct_7x14
316    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
317	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
318EXTERN(void) jpeg_idct_6x12
319    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
320	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
321EXTERN(void) jpeg_idct_5x10
322    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
323	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
324EXTERN(void) jpeg_idct_4x8
325    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
326	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
327EXTERN(void) jpeg_idct_3x6
328    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
329	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
330EXTERN(void) jpeg_idct_2x4
331    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
332	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
333EXTERN(void) jpeg_idct_1x2
334    JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
335	 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
336
337
338/*
339 * Macros for handling fixed-point arithmetic; these are used by many
340 * but not all of the DCT/IDCT modules.
341 *
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.
346 */
347
348#define ONE	((INT32) 1)
349#define CONST_SCALE (ONE << CONST_BITS)
350
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.
354 */
355
356#define FIX(x)	((INT32) ((x) * CONST_SCALE + 0.5))
357
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.
361 */
362
363#define DESCALE(x,n)  RIGHT_SHIFT((x) + (ONE << ((n)-1)), n)
364
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.
372 */
373
374#ifdef SHORTxSHORT_32		/* may work if 'int' is 32 bits */
375#define MULTIPLY16C16(var,const)  (((INT16) (var)) * ((INT16) (const)))
376#endif
377#ifdef SHORTxLCONST_32		/* known to work with Microsoft C 6.0 */
378#define MULTIPLY16C16(var,const)  (((INT16) (var)) * ((INT32) (const)))
379#endif
380
381#ifndef MULTIPLY16C16		/* default definition */
382#define MULTIPLY16C16(var,const)  ((var) * (const))
383#endif
384
385/* Same except both inputs are variables. */
386
387#ifdef SHORTxSHORT_32		/* may work if 'int' is 32 bits */
388#define MULTIPLY16V16(var1,var2)  (((INT16) (var1)) * ((INT16) (var2)))
389#endif
390
391#ifndef MULTIPLY16V16		/* default definition */
392#define MULTIPLY16V16(var1,var2)  ((var1) * (var2))
393#endif