jddctmgr.c revision 71ee859f6d3b654092fe1cba126d2c176a201196 
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 */
41extern void armv6_idct(short *coefs, int *quans, unsigned char **rows, int col);
42
43void 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
54extern short __attribute__((aligned(16))) quantptrSSE[DCTSIZE2];
55extern 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
61extern 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
83typedef 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
94typedef my_idct_controller * my_idct_ptr;
95
96
97/* Allocated multiplier tables: big enough for any supported variant */
98
99typedef 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
128METHODDEF(void)
129start_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
332GLOBAL(void)
333jinit_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