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/media/libjpeg/jdmerge.c

http://github.com/zpao/v8monkey
C | 409 lines | 254 code | 46 blank | 109 comment | 17 complexity | f37af3a74472518e1a28dbd997b5bbb1 MD5 | raw file
  1/*
  2 * jdmerge.c
  3 *
  4 * Copyright (C) 1994-1996, Thomas G. Lane.
  5 * Copyright 2009 Pierre Ossman <ossman@cendio.se> for Cendio AB
  6 * Copyright (C) 2009, D. R. Commander.
  7 * This file is part of the Independent JPEG Group's software.
  8 * For conditions of distribution and use, see the accompanying README file.
  9 *
 10 * This file contains code for merged upsampling/color conversion.
 11 *
 12 * This file combines functions from jdsample.c and jdcolor.c;
 13 * read those files first to understand what's going on.
 14 *
 15 * When the chroma components are to be upsampled by simple replication
 16 * (ie, box filtering), we can save some work in color conversion by
 17 * calculating all the output pixels corresponding to a pair of chroma
 18 * samples at one time.  In the conversion equations
 19 *	R = Y           + K1 * Cr
 20 *	G = Y + K2 * Cb + K3 * Cr
 21 *	B = Y + K4 * Cb
 22 * only the Y term varies among the group of pixels corresponding to a pair
 23 * of chroma samples, so the rest of the terms can be calculated just once.
 24 * At typical sampling ratios, this eliminates half or three-quarters of the
 25 * multiplications needed for color conversion.
 26 *
 27 * This file currently provides implementations for the following cases:
 28 *	YCbCr => RGB color conversion only.
 29 *	Sampling ratios of 2h1v or 2h2v.
 30 *	No scaling needed at upsample time.
 31 *	Corner-aligned (non-CCIR601) sampling alignment.
 32 * Other special cases could be added, but in most applications these are
 33 * the only common cases.  (For uncommon cases we fall back on the more
 34 * general code in jdsample.c and jdcolor.c.)
 35 */
 36
 37#define JPEG_INTERNALS
 38#include "jinclude.h"
 39#include "jpeglib.h"
 40#include "jsimd.h"
 41
 42#ifdef UPSAMPLE_MERGING_SUPPORTED
 43
 44
 45/* Private subobject */
 46
 47typedef struct {
 48  struct jpeg_upsampler pub;	/* public fields */
 49
 50  /* Pointer to routine to do actual upsampling/conversion of one row group */
 51  JMETHOD(void, upmethod, (j_decompress_ptr cinfo,
 52			   JSAMPIMAGE input_buf, JDIMENSION in_row_group_ctr,
 53			   JSAMPARRAY output_buf));
 54
 55  /* Private state for YCC->RGB conversion */
 56  int * Cr_r_tab;		/* => table for Cr to R conversion */
 57  int * Cb_b_tab;		/* => table for Cb to B conversion */
 58  INT32 * Cr_g_tab;		/* => table for Cr to G conversion */
 59  INT32 * Cb_g_tab;		/* => table for Cb to G conversion */
 60
 61  /* For 2:1 vertical sampling, we produce two output rows at a time.
 62   * We need a "spare" row buffer to hold the second output row if the
 63   * application provides just a one-row buffer; we also use the spare
 64   * to discard the dummy last row if the image height is odd.
 65   */
 66  JSAMPROW spare_row;
 67  boolean spare_full;		/* T if spare buffer is occupied */
 68
 69  JDIMENSION out_row_width;	/* samples per output row */
 70  JDIMENSION rows_to_go;	/* counts rows remaining in image */
 71} my_upsampler;
 72
 73typedef my_upsampler * my_upsample_ptr;
 74
 75#define SCALEBITS	16	/* speediest right-shift on some machines */
 76#define ONE_HALF	((INT32) 1 << (SCALEBITS-1))
 77#define FIX(x)		((INT32) ((x) * (1L<<SCALEBITS) + 0.5))
 78
 79
 80/*
 81 * Initialize tables for YCC->RGB colorspace conversion.
 82 * This is taken directly from jdcolor.c; see that file for more info.
 83 */
 84
 85LOCAL(void)
 86build_ycc_rgb_table (j_decompress_ptr cinfo)
 87{
 88  my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample;
 89  int i;
 90  INT32 x;
 91  SHIFT_TEMPS
 92
 93  upsample->Cr_r_tab = (int *)
 94    (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
 95				(MAXJSAMPLE+1) * SIZEOF(int));
 96  upsample->Cb_b_tab = (int *)
 97    (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
 98				(MAXJSAMPLE+1) * SIZEOF(int));
 99  upsample->Cr_g_tab = (INT32 *)
100    (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
101				(MAXJSAMPLE+1) * SIZEOF(INT32));
102  upsample->Cb_g_tab = (INT32 *)
103    (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
104				(MAXJSAMPLE+1) * SIZEOF(INT32));
105
106  for (i = 0, x = -CENTERJSAMPLE; i <= MAXJSAMPLE; i++, x++) {
107    /* i is the actual input pixel value, in the range 0..MAXJSAMPLE */
108    /* The Cb or Cr value we are thinking of is x = i - CENTERJSAMPLE */
109    /* Cr=>R value is nearest int to 1.40200 * x */
110    upsample->Cr_r_tab[i] = (int)
111		    RIGHT_SHIFT(FIX(1.40200) * x + ONE_HALF, SCALEBITS);
112    /* Cb=>B value is nearest int to 1.77200 * x */
113    upsample->Cb_b_tab[i] = (int)
114		    RIGHT_SHIFT(FIX(1.77200) * x + ONE_HALF, SCALEBITS);
115    /* Cr=>G value is scaled-up -0.71414 * x */
116    upsample->Cr_g_tab[i] = (- FIX(0.71414)) * x;
117    /* Cb=>G value is scaled-up -0.34414 * x */
118    /* We also add in ONE_HALF so that need not do it in inner loop */
119    upsample->Cb_g_tab[i] = (- FIX(0.34414)) * x + ONE_HALF;
120  }
121}
122
123
124/*
125 * Initialize for an upsampling pass.
126 */
127
128METHODDEF(void)
129start_pass_merged_upsample (j_decompress_ptr cinfo)
130{
131  my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample;
132
133  /* Mark the spare buffer empty */
134  upsample->spare_full = FALSE;
135  /* Initialize total-height counter for detecting bottom of image */
136  upsample->rows_to_go = cinfo->output_height;
137}
138
139
140/*
141 * Control routine to do upsampling (and color conversion).
142 *
143 * The control routine just handles the row buffering considerations.
144 */
145
146METHODDEF(void)
147merged_2v_upsample (j_decompress_ptr cinfo,
148		    JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr,
149		    JDIMENSION in_row_groups_avail,
150		    JSAMPARRAY output_buf, JDIMENSION *out_row_ctr,
151		    JDIMENSION out_rows_avail)
152/* 2:1 vertical sampling case: may need a spare row. */
153{
154  my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample;
155  JSAMPROW work_ptrs[2];
156  JDIMENSION num_rows;		/* number of rows returned to caller */
157
158  if (upsample->spare_full) {
159    /* If we have a spare row saved from a previous cycle, just return it. */
160    jcopy_sample_rows(& upsample->spare_row, 0, output_buf + *out_row_ctr, 0,
161		      1, upsample->out_row_width);
162    num_rows = 1;
163    upsample->spare_full = FALSE;
164  } else {
165    /* Figure number of rows to return to caller. */
166    num_rows = 2;
167    /* Not more than the distance to the end of the image. */
168    if (num_rows > upsample->rows_to_go)
169      num_rows = upsample->rows_to_go;
170    /* And not more than what the client can accept: */
171    out_rows_avail -= *out_row_ctr;
172    if (num_rows > out_rows_avail)
173      num_rows = out_rows_avail;
174    /* Create output pointer array for upsampler. */
175    work_ptrs[0] = output_buf[*out_row_ctr];
176    if (num_rows > 1) {
177      work_ptrs[1] = output_buf[*out_row_ctr + 1];
178    } else {
179      work_ptrs[1] = upsample->spare_row;
180      upsample->spare_full = TRUE;
181    }
182    /* Now do the upsampling. */
183    (*upsample->upmethod) (cinfo, input_buf, *in_row_group_ctr, work_ptrs);
184  }
185
186  /* Adjust counts */
187  *out_row_ctr += num_rows;
188  upsample->rows_to_go -= num_rows;
189  /* When the buffer is emptied, declare this input row group consumed */
190  if (! upsample->spare_full)
191    (*in_row_group_ctr)++;
192}
193
194
195METHODDEF(void)
196merged_1v_upsample (j_decompress_ptr cinfo,
197		    JSAMPIMAGE input_buf, JDIMENSION *in_row_group_ctr,
198		    JDIMENSION in_row_groups_avail,
199		    JSAMPARRAY output_buf, JDIMENSION *out_row_ctr,
200		    JDIMENSION out_rows_avail)
201/* 1:1 vertical sampling case: much easier, never need a spare row. */
202{
203  my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample;
204
205  /* Just do the upsampling. */
206  (*upsample->upmethod) (cinfo, input_buf, *in_row_group_ctr,
207			 output_buf + *out_row_ctr);
208  /* Adjust counts */
209  (*out_row_ctr)++;
210  (*in_row_group_ctr)++;
211}
212
213
214/*
215 * These are the routines invoked by the control routines to do
216 * the actual upsampling/conversion.  One row group is processed per call.
217 *
218 * Note: since we may be writing directly into application-supplied buffers,
219 * we have to be honest about the output width; we can't assume the buffer
220 * has been rounded up to an even width.
221 */
222
223
224/*
225 * Upsample and color convert for the case of 2:1 horizontal and 1:1 vertical.
226 */
227
228METHODDEF(void)
229h2v1_merged_upsample (j_decompress_ptr cinfo,
230		      JSAMPIMAGE input_buf, JDIMENSION in_row_group_ctr,
231		      JSAMPARRAY output_buf)
232{
233  my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample;
234  register int y, cred, cgreen, cblue;
235  int cb, cr;
236  register JSAMPROW outptr;
237  JSAMPROW inptr0, inptr1, inptr2;
238  JDIMENSION col;
239  /* copy these pointers into registers if possible */
240  register JSAMPLE * range_limit = cinfo->sample_range_limit;
241  int * Crrtab = upsample->Cr_r_tab;
242  int * Cbbtab = upsample->Cb_b_tab;
243  INT32 * Crgtab = upsample->Cr_g_tab;
244  INT32 * Cbgtab = upsample->Cb_g_tab;
245  SHIFT_TEMPS
246
247  inptr0 = input_buf[0][in_row_group_ctr];
248  inptr1 = input_buf[1][in_row_group_ctr];
249  inptr2 = input_buf[2][in_row_group_ctr];
250  outptr = output_buf[0];
251  /* Loop for each pair of output pixels */
252  for (col = cinfo->output_width >> 1; col > 0; col--) {
253    /* Do the chroma part of the calculation */
254    cb = GETJSAMPLE(*inptr1++);
255    cr = GETJSAMPLE(*inptr2++);
256    cred = Crrtab[cr];
257    cgreen = (int) RIGHT_SHIFT(Cbgtab[cb] + Crgtab[cr], SCALEBITS);
258    cblue = Cbbtab[cb];
259    /* Fetch 2 Y values and emit 2 pixels */
260    y  = GETJSAMPLE(*inptr0++);
261    outptr[rgb_red[cinfo->out_color_space]] =   range_limit[y + cred];
262    outptr[rgb_green[cinfo->out_color_space]] = range_limit[y + cgreen];
263    outptr[rgb_blue[cinfo->out_color_space]] =  range_limit[y + cblue];
264    outptr += rgb_pixelsize[cinfo->out_color_space];
265    y  = GETJSAMPLE(*inptr0++);
266    outptr[rgb_red[cinfo->out_color_space]] =   range_limit[y + cred];
267    outptr[rgb_green[cinfo->out_color_space]] = range_limit[y + cgreen];
268    outptr[rgb_blue[cinfo->out_color_space]] =  range_limit[y + cblue];
269    outptr += rgb_pixelsize[cinfo->out_color_space];
270  }
271  /* If image width is odd, do the last output column separately */
272  if (cinfo->output_width & 1) {
273    cb = GETJSAMPLE(*inptr1);
274    cr = GETJSAMPLE(*inptr2);
275    cred = Crrtab[cr];
276    cgreen = (int) RIGHT_SHIFT(Cbgtab[cb] + Crgtab[cr], SCALEBITS);
277    cblue = Cbbtab[cb];
278    y  = GETJSAMPLE(*inptr0);
279    outptr[rgb_red[cinfo->out_color_space]] =   range_limit[y + cred];
280    outptr[rgb_green[cinfo->out_color_space]] = range_limit[y + cgreen];
281    outptr[rgb_blue[cinfo->out_color_space]] =  range_limit[y + cblue];
282  }
283}
284
285
286/*
287 * Upsample and color convert for the case of 2:1 horizontal and 2:1 vertical.
288 */
289
290METHODDEF(void)
291h2v2_merged_upsample (j_decompress_ptr cinfo,
292		      JSAMPIMAGE input_buf, JDIMENSION in_row_group_ctr,
293		      JSAMPARRAY output_buf)
294{
295  my_upsample_ptr upsample = (my_upsample_ptr) cinfo->upsample;
296  register int y, cred, cgreen, cblue;
297  int cb, cr;
298  register JSAMPROW outptr0, outptr1;
299  JSAMPROW inptr00, inptr01, inptr1, inptr2;
300  JDIMENSION col;
301  /* copy these pointers into registers if possible */
302  register JSAMPLE * range_limit = cinfo->sample_range_limit;
303  int * Crrtab = upsample->Cr_r_tab;
304  int * Cbbtab = upsample->Cb_b_tab;
305  INT32 * Crgtab = upsample->Cr_g_tab;
306  INT32 * Cbgtab = upsample->Cb_g_tab;
307  SHIFT_TEMPS
308
309  inptr00 = input_buf[0][in_row_group_ctr*2];
310  inptr01 = input_buf[0][in_row_group_ctr*2 + 1];
311  inptr1 = input_buf[1][in_row_group_ctr];
312  inptr2 = input_buf[2][in_row_group_ctr];
313  outptr0 = output_buf[0];
314  outptr1 = output_buf[1];
315  /* Loop for each group of output pixels */
316  for (col = cinfo->output_width >> 1; col > 0; col--) {
317    /* Do the chroma part of the calculation */
318    cb = GETJSAMPLE(*inptr1++);
319    cr = GETJSAMPLE(*inptr2++);
320    cred = Crrtab[cr];
321    cgreen = (int) RIGHT_SHIFT(Cbgtab[cb] + Crgtab[cr], SCALEBITS);
322    cblue = Cbbtab[cb];
323    /* Fetch 4 Y values and emit 4 pixels */
324    y  = GETJSAMPLE(*inptr00++);
325    outptr0[rgb_red[cinfo->out_color_space]] =   range_limit[y + cred];
326    outptr0[rgb_green[cinfo->out_color_space]] = range_limit[y + cgreen];
327    outptr0[rgb_blue[cinfo->out_color_space]] =  range_limit[y + cblue];
328    outptr0 += RGB_PIXELSIZE;
329    y  = GETJSAMPLE(*inptr00++);
330    outptr0[rgb_red[cinfo->out_color_space]] =   range_limit[y + cred];
331    outptr0[rgb_green[cinfo->out_color_space]] = range_limit[y + cgreen];
332    outptr0[rgb_blue[cinfo->out_color_space]] =  range_limit[y + cblue];
333    outptr0 += RGB_PIXELSIZE;
334    y  = GETJSAMPLE(*inptr01++);
335    outptr1[rgb_red[cinfo->out_color_space]] =   range_limit[y + cred];
336    outptr1[rgb_green[cinfo->out_color_space]] = range_limit[y + cgreen];
337    outptr1[rgb_blue[cinfo->out_color_space]] =  range_limit[y + cblue];
338    outptr1 += RGB_PIXELSIZE;
339    y  = GETJSAMPLE(*inptr01++);
340    outptr1[rgb_red[cinfo->out_color_space]] =   range_limit[y + cred];
341    outptr1[rgb_green[cinfo->out_color_space]] = range_limit[y + cgreen];
342    outptr1[rgb_blue[cinfo->out_color_space]] =  range_limit[y + cblue];
343    outptr1 += RGB_PIXELSIZE;
344  }
345  /* If image width is odd, do the last output column separately */
346  if (cinfo->output_width & 1) {
347    cb = GETJSAMPLE(*inptr1);
348    cr = GETJSAMPLE(*inptr2);
349    cred = Crrtab[cr];
350    cgreen = (int) RIGHT_SHIFT(Cbgtab[cb] + Crgtab[cr], SCALEBITS);
351    cblue = Cbbtab[cb];
352    y  = GETJSAMPLE(*inptr00);
353    outptr0[rgb_red[cinfo->out_color_space]] =   range_limit[y + cred];
354    outptr0[rgb_green[cinfo->out_color_space]] = range_limit[y + cgreen];
355    outptr0[rgb_blue[cinfo->out_color_space]] =  range_limit[y + cblue];
356    y  = GETJSAMPLE(*inptr01);
357    outptr1[rgb_red[cinfo->out_color_space]] =   range_limit[y + cred];
358    outptr1[rgb_green[cinfo->out_color_space]] = range_limit[y + cgreen];
359    outptr1[rgb_blue[cinfo->out_color_space]] =  range_limit[y + cblue];
360  }
361}
362
363
364/*
365 * Module initialization routine for merged upsampling/color conversion.
366 *
367 * NB: this is called under the conditions determined by use_merged_upsample()
368 * in jdmaster.c.  That routine MUST correspond to the actual capabilities
369 * of this module; no safety checks are made here.
370 */
371
372GLOBAL(void)
373jinit_merged_upsampler (j_decompress_ptr cinfo)
374{
375  my_upsample_ptr upsample;
376
377  upsample = (my_upsample_ptr)
378    (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
379				SIZEOF(my_upsampler));
380  cinfo->upsample = (struct jpeg_upsampler *) upsample;
381  upsample->pub.start_pass = start_pass_merged_upsample;
382  upsample->pub.need_context_rows = FALSE;
383
384  upsample->out_row_width = cinfo->output_width * cinfo->out_color_components;
385
386  if (cinfo->max_v_samp_factor == 2) {
387    upsample->pub.upsample = merged_2v_upsample;
388    if (jsimd_can_h2v2_merged_upsample())
389      upsample->upmethod = jsimd_h2v2_merged_upsample;
390    else
391      upsample->upmethod = h2v2_merged_upsample;
392    /* Allocate a spare row buffer */
393    upsample->spare_row = (JSAMPROW)
394      (*cinfo->mem->alloc_large) ((j_common_ptr) cinfo, JPOOL_IMAGE,
395		(size_t) (upsample->out_row_width * SIZEOF(JSAMPLE)));
396  } else {
397    upsample->pub.upsample = merged_1v_upsample;
398    if (jsimd_can_h2v1_merged_upsample())
399      upsample->upmethod = jsimd_h2v1_merged_upsample;
400    else
401      upsample->upmethod = h2v1_merged_upsample;
402    /* No spare row needed */
403    upsample->spare_row = NULL;
404  }
405
406  build_ycc_rgb_table(cinfo);
407}
408
409#endif /* UPSAMPLE_MERGING_SUPPORTED */