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comparison mupdf-source/thirdparty/libjpeg/jdct.h @ 2:b50eed0cc0ef upstream

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ADD: MuPDF v1.26.7: the MuPDF source as downloaded by a default build of PyMuPDF 1.26.4. The directory name has changed: no version number in the expanded directory now.
author Franz Glasner <fzglas.hg@dom66.de>
date Mon, 15 Sep 2025 11:43:07 +0200
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1:1d09e1dec1d9 2:b50eed0cc0ef
1 /*
2 * jdct.h
3 *
4 * Copyright (C) 1994-1996, Thomas G. Lane.
5 * Modified 2002-2023 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,
42 JSAMPARRAY sample_data,
43 JDIMENSION start_col));
44 typedef JMETHOD(void, float_DCT_method_ptr, (FAST_FLOAT * data,
45 JSAMPARRAY sample_data,
46 JDIMENSION start_col));
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 jRD3x6
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
169 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
170 EXTERN(void) jpeg_fdct_ifast
171 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
172 EXTERN(void) jpeg_fdct_float
173 JPP((FAST_FLOAT * data, JSAMPARRAY sample_data, JDIMENSION start_col));
174 EXTERN(void) jpeg_fdct_7x7
175 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
176 EXTERN(void) jpeg_fdct_6x6
177 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
178 EXTERN(void) jpeg_fdct_5x5
179 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
180 EXTERN(void) jpeg_fdct_4x4
181 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
182 EXTERN(void) jpeg_fdct_3x3
183 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
184 EXTERN(void) jpeg_fdct_2x2
185 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
186 EXTERN(void) jpeg_fdct_1x1
187 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
188 EXTERN(void) jpeg_fdct_9x9
189 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
190 EXTERN(void) jpeg_fdct_10x10
191 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
192 EXTERN(void) jpeg_fdct_11x11
193 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
194 EXTERN(void) jpeg_fdct_12x12
195 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
196 EXTERN(void) jpeg_fdct_13x13
197 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
198 EXTERN(void) jpeg_fdct_14x14
199 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
200 EXTERN(void) jpeg_fdct_15x15
201 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
202 EXTERN(void) jpeg_fdct_16x16
203 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
204 EXTERN(void) jpeg_fdct_16x8
205 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
206 EXTERN(void) jpeg_fdct_14x7
207 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
208 EXTERN(void) jpeg_fdct_12x6
209 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
210 EXTERN(void) jpeg_fdct_10x5
211 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
212 EXTERN(void) jpeg_fdct_8x4
213 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
214 EXTERN(void) jpeg_fdct_6x3
215 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
216 EXTERN(void) jpeg_fdct_4x2
217 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
218 EXTERN(void) jpeg_fdct_2x1
219 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
220 EXTERN(void) jpeg_fdct_8x16
221 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
222 EXTERN(void) jpeg_fdct_7x14
223 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
224 EXTERN(void) jpeg_fdct_6x12
225 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
226 EXTERN(void) jpeg_fdct_5x10
227 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
228 EXTERN(void) jpeg_fdct_4x8
229 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
230 EXTERN(void) jpeg_fdct_3x6
231 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
232 EXTERN(void) jpeg_fdct_2x4
233 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
234 EXTERN(void) jpeg_fdct_1x2
235 JPP((DCTELEM * data, JSAMPARRAY sample_data, JDIMENSION start_col));
236
237 EXTERN(void) jpeg_idct_islow
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_ifast
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_float
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_7x7
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_6x6
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_5x5
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_4x4
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_3x3
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_2x2
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_1x1
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_9x9
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_10x10
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_11x11
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_12x12
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_13x13
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_14x14
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_15x15
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_16x16
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_16x8
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_14x7
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_12x6
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_10x5
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_8x4
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_6x3
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_4x2
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_2x1
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_8x16
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_7x14
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_6x12
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_5x10
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_4x8
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_3x6
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_2x4
334 JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
335 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
336 EXTERN(void) jpeg_idct_1x2
337 JPP((j_decompress_ptr cinfo, jpeg_component_info * compptr,
338 JCOEFPTR coef_block, JSAMPARRAY output_buf, JDIMENSION output_col));
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 /* Multiply an INT32 variable by an INT32 constant to yield an INT32 result.
362 * This macro is used only when the two inputs will actually be no more than
363 * 16 bits wide, so that a 16x16->32 bit multiply can be used instead of a
364 * full 32x32 multiply. This provides a useful speedup on many machines.
365 * Unfortunately there is no way to specify a 16x16->32 multiply portably
366 * in C, but some C compilers will do the right thing if you provide the
367 * correct combination of casts.
368 */
369
370 #ifdef SHORTxSHORT_32 /* may work if 'int' is 32 bits */
371 #define MULTIPLY16C16(var,const) (((INT16) (var)) * ((INT16) (const)))
372 #endif
373 #ifdef SHORTxLCONST_32 /* known to work with Microsoft C 6.0 */
374 #define MULTIPLY16C16(var,const) (((INT16) (var)) * ((INT32) (const)))
375 #endif
376
377 #ifndef MULTIPLY16C16 /* default definition */
378 #define MULTIPLY16C16(var,const) ((var) * (const))
379 #endif
380
381 /* Same except both inputs are variables. */
382
383 #ifdef SHORTxSHORT_32 /* may work if 'int' is 32 bits */
384 #define MULTIPLY16V16(var1,var2) (((INT16) (var1)) * ((INT16) (var2)))
385 #endif
386
387 #ifndef MULTIPLY16V16 /* default definition */
388 #define MULTIPLY16V16(var1,var2) ((var1) * (var2))
389 #endif
390
391 /* Like RIGHT_SHIFT, but applies to a DCTELEM.
392 * We assume that int right shift is unsigned if INT32 right shift is.
393 */
394
395 #ifdef RIGHT_SHIFT_IS_UNSIGNED
396 #define ISHIFT_TEMPS DCTELEM ishift_temp;
397 #if BITS_IN_JSAMPLE == 8
398 #define DCTELEMBITS 16 /* DCTELEM may be 16 or 32 bits */
399 #else
400 #define DCTELEMBITS 32 /* DCTELEM must be 32 bits */
401 #endif
402 #define IRIGHT_SHIFT(x,shft) \
403 ((ishift_temp = (x)) < 0 ? \
404 (ishift_temp >> (shft)) | ((~((DCTELEM) 0)) << (DCTELEMBITS-(shft))) : \
405 (ishift_temp >> (shft)))
406 #else
407 #define ISHIFT_TEMPS
408 #define IRIGHT_SHIFT(x,shft) ((x) >> (shft))
409 #endif