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