1 /*
2 * jddctmgr.c
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 file contains the inverse-DCT management logic.
9 * This code selects a particular IDCT implementation to be used,
10 * and it performs related housekeeping chores. No code in this file
11 * is executed per IDCT step, only during output pass setup.
12 *
13 * Note that the IDCT routines are responsible for performing coefficient
14 * dequantization as well as the IDCT proper. This module sets up the
15 * dequantization multiplier table needed by the IDCT routine.
16 */
17
18 #define JPEG_INTERNALS
19 #include "jinclude.h"
20 #include "jpeglib.h"
21 #include "jdct.h" /* Private declarations for DCT subsystem */
22
23 #ifdef ANDROID_ARMV6_IDCT
24 #undef ANDROID_ARMV6_IDCT
25 #ifdef __arm__
26 #include <machine/cpu-features.h>
27 #if __ARM_ARCH__ >= 6
28 #define ANDROID_ARMV6_IDCT
29 #else
30 #warning "ANDROID_ARMV6_IDCT is disabled"
31 #endif
32 #endif
33 #endif
34
35 #ifdef ANDROID_ARMV6_IDCT
36
37 /* Intentionally declare the prototype with arguments of primitive types instead
38 * of type-defined ones. This will at least generate some warnings if jmorecfg.h
39 * is changed and becomes incompatible with the assembly code.
40 */
41 extern void armv6_idct(short *coefs, int *quans, unsigned char **rows, int col);
42
jpeg_idct_armv6(j_decompress_ptr cinfo,jpeg_component_info * compptr,JCOEFPTR coef_block,JSAMPARRAY output_buf,JDIMENSION output_col)43 void jpeg_idct_armv6 (j_decompress_ptr cinfo, jpeg_component_info * compptr,
44 JCOEFPTR coef_block,
45 JSAMPARRAY output_buf, JDIMENSION output_col)
46 {
47 IFAST_MULT_TYPE *dct_table = (IFAST_MULT_TYPE *)compptr->dct_table;
48 armv6_idct(coef_block, dct_table, output_buf, output_col);
49 }
50
51 #endif
52
53 #ifdef ANDROID_INTELSSE2_IDCT
54 extern short __attribute__((aligned(16))) quantptrSSE[DCTSIZE2];
55 extern void jpeg_idct_intelsse (j_decompress_ptr cinfo, jpeg_component_info * compptr,
56 JCOEFPTR coef_block,
57 JSAMPARRAY output_buf, JDIMENSION output_col);
58 #endif
59
60 #ifdef ANDROID_MIPS_IDCT
61 extern void jpeg_idct_mips(j_decompress_ptr, jpeg_component_info *, JCOEFPTR, JSAMPARRAY, JDIMENSION);
62 #endif
63
64 /*
65 * The decompressor input side (jdinput.c) saves away the appropriate
66 * quantization table for each component at the start of the first scan
67 * involving that component. (This is necessary in order to correctly
68 * decode files that reuse Q-table slots.)
69 * When we are ready to make an output pass, the saved Q-table is converted
70 * to a multiplier table that will actually be used by the IDCT routine.
71 * The multiplier table contents are IDCT-method-dependent. To support
72 * application changes in IDCT method between scans, we can remake the
73 * multiplier tables if necessary.
74 * In buffered-image mode, the first output pass may occur before any data
75 * has been seen for some components, and thus before their Q-tables have
76 * been saved away. To handle this case, multiplier tables are preset
77 * to zeroes; the result of the IDCT will be a neutral gray level.
78 */
79
80
81 /* Private subobject for this module */
82
83 typedef struct {
84 struct jpeg_inverse_dct pub; /* public fields */
85
86 /* This array contains the IDCT method code that each multiplier table
87 * is currently set up for, or -1 if it's not yet set up.
88 * The actual multiplier tables are pointed to by dct_table in the
89 * per-component comp_info structures.
90 */
91 int cur_method[MAX_COMPONENTS];
92 } my_idct_controller;
93
94 typedef my_idct_controller * my_idct_ptr;
95
96
97 /* Allocated multiplier tables: big enough for any supported variant */
98
99 typedef union {
100 ISLOW_MULT_TYPE islow_array[DCTSIZE2];
101 #ifdef DCT_IFAST_SUPPORTED
102 IFAST_MULT_TYPE ifast_array[DCTSIZE2];
103 #endif
104 #ifdef DCT_FLOAT_SUPPORTED
105 FLOAT_MULT_TYPE float_array[DCTSIZE2];
106 #endif
107 } multiplier_table;
108
109
110 /* The current scaled-IDCT routines require ISLOW-style multiplier tables,
111 * so be sure to compile that code if either ISLOW or SCALING is requested.
112 */
113 #ifdef DCT_ISLOW_SUPPORTED
114 #define PROVIDE_ISLOW_TABLES
115 #else
116 #ifdef IDCT_SCALING_SUPPORTED
117 #define PROVIDE_ISLOW_TABLES
118 #endif
119 #endif
120
121
122 /*
123 * Prepare for an output pass.
124 * Here we select the proper IDCT routine for each component and build
125 * a matching multiplier table.
126 */
127
128 METHODDEF(void)
start_pass(j_decompress_ptr cinfo)129 start_pass (j_decompress_ptr cinfo)
130 {
131 my_idct_ptr idct = (my_idct_ptr) cinfo->idct;
132 int ci, i;
133 jpeg_component_info *compptr;
134 int method = 0;
135 inverse_DCT_method_ptr method_ptr = NULL;
136 JQUANT_TBL * qtbl;
137
138 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
139 ci++, compptr++) {
140 /* Select the proper IDCT routine for this component's scaling */
141 switch (compptr->DCT_scaled_size) {
142 #ifdef IDCT_SCALING_SUPPORTED
143 case 1:
144 method_ptr = jpeg_idct_1x1;
145 method = JDCT_ISLOW; /* jidctred uses islow-style table */
146 break;
147 case 2:
148 method_ptr = jpeg_idct_2x2;
149 method = JDCT_ISLOW; /* jidctred uses islow-style table */
150 break;
151 case 4:
152 method_ptr = jpeg_idct_4x4;
153 method = JDCT_ISLOW; /* jidctred uses islow-style table */
154 break;
155 #endif
156 case DCTSIZE:
157 switch (cinfo->dct_method) {
158 #ifdef ANDROID_ARMV6_IDCT
159 case JDCT_ISLOW:
160 case JDCT_IFAST:
161 method_ptr = jpeg_idct_armv6;
162 method = JDCT_IFAST;
163 break;
164 #else /* ANDROID_ARMV6_IDCT */
165 #ifdef ANDROID_INTELSSE2_IDCT
166 case JDCT_ISLOW:
167 case JDCT_IFAST:
168 method_ptr = jpeg_idct_intelsse;
169 method = JDCT_ISLOW; /* Use quant table of ISLOW.*/
170 break;
171 #else /* ANDROID_INTELSSE2_IDCT */
172 #ifdef ANDROID_MIPS_IDCT
173 case JDCT_ISLOW:
174 case JDCT_IFAST:
175 method_ptr = jpeg_idct_mips;
176 method = JDCT_IFAST;
177 break;
178 #else /* ANDROID_MIPS_IDCT */
179 #ifdef DCT_ISLOW_SUPPORTED
180 case JDCT_ISLOW:
181 method_ptr = jpeg_idct_islow;
182 method = JDCT_ISLOW;
183 break;
184 #endif
185 #ifdef DCT_IFAST_SUPPORTED
186 case JDCT_IFAST:
187 method_ptr = jpeg_idct_ifast;
188 method = JDCT_IFAST;
189 break;
190 #endif
191 #endif /* ANDROID_MIPS_IDCT */
192 #endif /* ANDROID_INTELSSE2_IDCT*/
193 #endif /* ANDROID_ARMV6_IDCT */
194 #ifdef DCT_FLOAT_SUPPORTED
195 case JDCT_FLOAT:
196 method_ptr = jpeg_idct_float;
197 method = JDCT_FLOAT;
198 break;
199 #endif
200 default:
201 ERREXIT(cinfo, JERR_NOT_COMPILED);
202 break;
203 }
204 break;
205 default:
206 ERREXIT1(cinfo, JERR_BAD_DCTSIZE, compptr->DCT_scaled_size);
207 break;
208 }
209 idct->pub.inverse_DCT[ci] = method_ptr;
210 /* Create multiplier table from quant table.
211 * However, we can skip this if the component is uninteresting
212 * or if we already built the table. Also, if no quant table
213 * has yet been saved for the component, we leave the
214 * multiplier table all-zero; we'll be reading zeroes from the
215 * coefficient controller's buffer anyway.
216 */
217 if (! compptr->component_needed || idct->cur_method[ci] == method)
218 continue;
219 qtbl = compptr->quant_table;
220 if (qtbl == NULL) /* happens if no data yet for component */
221 continue;
222 idct->cur_method[ci] = method;
223 switch (method) {
224 #ifdef PROVIDE_ISLOW_TABLES
225 case JDCT_ISLOW:
226 {
227 /* For LL&M IDCT method, multipliers are equal to raw quantization
228 * coefficients, but are stored as ints to ensure access efficiency.
229 */
230 ISLOW_MULT_TYPE * ismtbl = (ISLOW_MULT_TYPE *) compptr->dct_table;
231 for (i = 0; i < DCTSIZE2; i++) {
232 ismtbl[i] = (ISLOW_MULT_TYPE) qtbl->quantval[i];
233 }
234 }
235 break;
236 #endif
237 #ifdef DCT_IFAST_SUPPORTED
238 case JDCT_IFAST:
239 {
240 /* For AA&N IDCT method, multipliers are equal to quantization
241 * coefficients scaled by scalefactor[row]*scalefactor[col], where
242 * scalefactor[0] = 1
243 * scalefactor[k] = cos(k*PI/16) * sqrt(2) for k=1..7
244 * For integer operation, the multiplier table is to be scaled by
245 * IFAST_SCALE_BITS.
246 */
247 IFAST_MULT_TYPE * ifmtbl = (IFAST_MULT_TYPE *) compptr->dct_table;
248 #ifdef ANDROID_ARMV6_IDCT
249 /* Precomputed values scaled up by 15 bits. */
250 static const unsigned short scales[DCTSIZE2] = {
251 32768, 45451, 42813, 38531, 32768, 25746, 17734, 9041,
252 45451, 63042, 59384, 53444, 45451, 35710, 24598, 12540,
253 42813, 59384, 55938, 50343, 42813, 33638, 23170, 11812,
254 38531, 53444, 50343, 45308, 38531, 30274, 20853, 10631,
255 32768, 45451, 42813, 38531, 32768, 25746, 17734, 9041,
256 25746, 35710, 33638, 30274, 25746, 20228, 13933, 7103,
257 17734, 24598, 23170, 20853, 17734, 13933, 9598, 4893,
258 9041, 12540, 11812, 10631, 9041, 7103, 4893, 2494,
259 };
260 /* Inverse map of [7, 5, 1, 3, 0, 2, 4, 6]. */
261 static const char orders[DCTSIZE] = {4, 2, 5, 3, 6, 1, 7, 0};
262 /* Reorder the columns after transposing. */
263 for (i = 0; i < DCTSIZE2; ++i) {
264 int j = ((i & 7) << 3) + orders[i >> 3];
265 ifmtbl[j] = (qtbl->quantval[i] * scales[i] + 2) >> 2;
266 }
267 #else /* ANDROID_ARMV6_IDCT */
268
269 #define CONST_BITS 14
270 static const INT16 aanscales[DCTSIZE2] = {
271 /* precomputed values scaled up by 14 bits */
272 16384, 22725, 21407, 19266, 16384, 12873, 8867, 4520,
273 22725, 31521, 29692, 26722, 22725, 17855, 12299, 6270,
274 21407, 29692, 27969, 25172, 21407, 16819, 11585, 5906,
275 19266, 26722, 25172, 22654, 19266, 15137, 10426, 5315,
276 16384, 22725, 21407, 19266, 16384, 12873, 8867, 4520,
277 12873, 17855, 16819, 15137, 12873, 10114, 6967, 3552,
278 8867, 12299, 11585, 10426, 8867, 6967, 4799, 2446,
279 4520, 6270, 5906, 5315, 4520, 3552, 2446, 1247
280 };
281 SHIFT_TEMPS
282
283 for (i = 0; i < DCTSIZE2; i++) {
284 ifmtbl[i] = (IFAST_MULT_TYPE)
285 DESCALE(MULTIPLY16V16((INT32) qtbl->quantval[i],
286 (INT32) aanscales[i]),
287 CONST_BITS-IFAST_SCALE_BITS);
288 }
289 #endif /* ANDROID_ARMV6_IDCT */
290 }
291 break;
292 #endif
293 #ifdef DCT_FLOAT_SUPPORTED
294 case JDCT_FLOAT:
295 {
296 /* For float AA&N IDCT method, multipliers are equal to quantization
297 * coefficients scaled by scalefactor[row]*scalefactor[col], where
298 * scalefactor[0] = 1
299 * scalefactor[k] = cos(k*PI/16) * sqrt(2) for k=1..7
300 */
301 FLOAT_MULT_TYPE * fmtbl = (FLOAT_MULT_TYPE *) compptr->dct_table;
302 int row, col;
303 static const double aanscalefactor[DCTSIZE] = {
304 1.0, 1.387039845, 1.306562965, 1.175875602,
305 1.0, 0.785694958, 0.541196100, 0.275899379
306 };
307
308 i = 0;
309 for (row = 0; row < DCTSIZE; row++) {
310 for (col = 0; col < DCTSIZE; col++) {
311 fmtbl[i] = (FLOAT_MULT_TYPE)
312 ((double) qtbl->quantval[i] *
313 aanscalefactor[row] * aanscalefactor[col]);
314 i++;
315 }
316 }
317 }
318 break;
319 #endif
320 default:
321 ERREXIT(cinfo, JERR_NOT_COMPILED);
322 break;
323 }
324 }
325 }
326
327
328 /*
329 * Initialize IDCT manager.
330 */
331
332 GLOBAL(void)
jinit_inverse_dct(j_decompress_ptr cinfo)333 jinit_inverse_dct (j_decompress_ptr cinfo)
334 {
335 my_idct_ptr idct;
336 int ci;
337 jpeg_component_info *compptr;
338
339 idct = (my_idct_ptr)
340 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
341 SIZEOF(my_idct_controller));
342 cinfo->idct = (struct jpeg_inverse_dct *) idct;
343 idct->pub.start_pass = start_pass;
344
345 for (ci = 0, compptr = cinfo->comp_info; ci < cinfo->num_components;
346 ci++, compptr++) {
347 /* Allocate and pre-zero a multiplier table for each component */
348 compptr->dct_table =
349 (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
350 SIZEOF(multiplier_table));
351 MEMZERO(compptr->dct_table, SIZEOF(multiplier_table));
352 /* Mark multiplier table not yet set up for any method */
353 idct->cur_method[ci] = -1;
354 }
355 }
356