1 /*
2  * jccolor.c
3  *
4  * This file was part of the Independent JPEG Group's software:
5  * Copyright (C) 1991-1996, Thomas G. Lane.
6  * libjpeg-turbo Modifications:
7  * Copyright 2009 Pierre Ossman <ossman@cendio.se> for Cendio AB
8  * Copyright (C) 2009-2012, 2015 D. R. Commander.
9  * Copyright (C) 2014, MIPS Technologies, Inc., California
10  * For conditions of distribution and use, see the accompanying README file.
11  *
12  * This file contains input colorspace conversion routines.
13  */
14 
15 #define JPEG_INTERNALS
16 #include "jinclude.h"
17 #include "jpeglib.h"
18 #include "jsimd.h"
19 #include "jconfigint.h"
20 
21 
22 /* Private subobject */
23 
24 typedef struct {
25   struct jpeg_color_converter pub; /* public fields */
26 
27   /* Private state for RGB->YCC conversion */
28   INT32 * rgb_ycc_tab;          /* => table for RGB to YCbCr conversion */
29 } my_color_converter;
30 
31 typedef my_color_converter * my_cconvert_ptr;
32 
33 
34 /**************** RGB -> YCbCr conversion: most common case **************/
35 
36 /*
37  * YCbCr is defined per CCIR 601-1, except that Cb and Cr are
38  * normalized to the range 0..MAXJSAMPLE rather than -0.5 .. 0.5.
39  * The conversion equations to be implemented are therefore
40  *      Y  =  0.29900 * R + 0.58700 * G + 0.11400 * B
41  *      Cb = -0.16874 * R - 0.33126 * G + 0.50000 * B  + CENTERJSAMPLE
42  *      Cr =  0.50000 * R - 0.41869 * G - 0.08131 * B  + CENTERJSAMPLE
43  * (These numbers are derived from TIFF 6.0 section 21, dated 3-June-92.)
44  * Note: older versions of the IJG code used a zero offset of MAXJSAMPLE/2,
45  * rather than CENTERJSAMPLE, for Cb and Cr.  This gave equal positive and
46  * negative swings for Cb/Cr, but meant that grayscale values (Cb=Cr=0)
47  * were not represented exactly.  Now we sacrifice exact representation of
48  * maximum red and maximum blue in order to get exact grayscales.
49  *
50  * To avoid floating-point arithmetic, we represent the fractional constants
51  * as integers scaled up by 2^16 (about 4 digits precision); we have to divide
52  * the products by 2^16, with appropriate rounding, to get the correct answer.
53  *
54  * For even more speed, we avoid doing any multiplications in the inner loop
55  * by precalculating the constants times R,G,B for all possible values.
56  * For 8-bit JSAMPLEs this is very reasonable (only 256 entries per table);
57  * for 12-bit samples it is still acceptable.  It's not very reasonable for
58  * 16-bit samples, but if you want lossless storage you shouldn't be changing
59  * colorspace anyway.
60  * The CENTERJSAMPLE offsets and the rounding fudge-factor of 0.5 are included
61  * in the tables to save adding them separately in the inner loop.
62  */
63 
64 #define SCALEBITS       16      /* speediest right-shift on some machines */
65 #define CBCR_OFFSET     ((INT32) CENTERJSAMPLE << SCALEBITS)
66 #define ONE_HALF        ((INT32) 1 << (SCALEBITS-1))
67 #define FIX(x)          ((INT32) ((x) * (1L<<SCALEBITS) + 0.5))
68 
69 /* We allocate one big table and divide it up into eight parts, instead of
70  * doing eight alloc_small requests.  This lets us use a single table base
71  * address, which can be held in a register in the inner loops on many
72  * machines (more than can hold all eight addresses, anyway).
73  */
74 
75 #define R_Y_OFF         0                       /* offset to R => Y section */
76 #define G_Y_OFF         (1*(MAXJSAMPLE+1))      /* offset to G => Y section */
77 #define B_Y_OFF         (2*(MAXJSAMPLE+1))      /* etc. */
78 #define R_CB_OFF        (3*(MAXJSAMPLE+1))
79 #define G_CB_OFF        (4*(MAXJSAMPLE+1))
80 #define B_CB_OFF        (5*(MAXJSAMPLE+1))
81 #define R_CR_OFF        B_CB_OFF                /* B=>Cb, R=>Cr are the same */
82 #define G_CR_OFF        (6*(MAXJSAMPLE+1))
83 #define B_CR_OFF        (7*(MAXJSAMPLE+1))
84 #define TABLE_SIZE      (8*(MAXJSAMPLE+1))
85 
86 
87 /* Include inline routines for colorspace extensions */
88 
89 #include "jccolext.c"
90 #undef RGB_RED
91 #undef RGB_GREEN
92 #undef RGB_BLUE
93 #undef RGB_PIXELSIZE
94 
95 #define RGB_RED EXT_RGB_RED
96 #define RGB_GREEN EXT_RGB_GREEN
97 #define RGB_BLUE EXT_RGB_BLUE
98 #define RGB_PIXELSIZE EXT_RGB_PIXELSIZE
99 #define rgb_ycc_convert_internal extrgb_ycc_convert_internal
100 #define rgb_gray_convert_internal extrgb_gray_convert_internal
101 #define rgb_rgb_convert_internal extrgb_rgb_convert_internal
102 #include "jccolext.c"
103 #undef RGB_RED
104 #undef RGB_GREEN
105 #undef RGB_BLUE
106 #undef RGB_PIXELSIZE
107 #undef rgb_ycc_convert_internal
108 #undef rgb_gray_convert_internal
109 #undef rgb_rgb_convert_internal
110 
111 #define RGB_RED EXT_RGBX_RED
112 #define RGB_GREEN EXT_RGBX_GREEN
113 #define RGB_BLUE EXT_RGBX_BLUE
114 #define RGB_PIXELSIZE EXT_RGBX_PIXELSIZE
115 #define rgb_ycc_convert_internal extrgbx_ycc_convert_internal
116 #define rgb_gray_convert_internal extrgbx_gray_convert_internal
117 #define rgb_rgb_convert_internal extrgbx_rgb_convert_internal
118 #include "jccolext.c"
119 #undef RGB_RED
120 #undef RGB_GREEN
121 #undef RGB_BLUE
122 #undef RGB_PIXELSIZE
123 #undef rgb_ycc_convert_internal
124 #undef rgb_gray_convert_internal
125 #undef rgb_rgb_convert_internal
126 
127 #define RGB_RED EXT_BGR_RED
128 #define RGB_GREEN EXT_BGR_GREEN
129 #define RGB_BLUE EXT_BGR_BLUE
130 #define RGB_PIXELSIZE EXT_BGR_PIXELSIZE
131 #define rgb_ycc_convert_internal extbgr_ycc_convert_internal
132 #define rgb_gray_convert_internal extbgr_gray_convert_internal
133 #define rgb_rgb_convert_internal extbgr_rgb_convert_internal
134 #include "jccolext.c"
135 #undef RGB_RED
136 #undef RGB_GREEN
137 #undef RGB_BLUE
138 #undef RGB_PIXELSIZE
139 #undef rgb_ycc_convert_internal
140 #undef rgb_gray_convert_internal
141 #undef rgb_rgb_convert_internal
142 
143 #define RGB_RED EXT_BGRX_RED
144 #define RGB_GREEN EXT_BGRX_GREEN
145 #define RGB_BLUE EXT_BGRX_BLUE
146 #define RGB_PIXELSIZE EXT_BGRX_PIXELSIZE
147 #define rgb_ycc_convert_internal extbgrx_ycc_convert_internal
148 #define rgb_gray_convert_internal extbgrx_gray_convert_internal
149 #define rgb_rgb_convert_internal extbgrx_rgb_convert_internal
150 #include "jccolext.c"
151 #undef RGB_RED
152 #undef RGB_GREEN
153 #undef RGB_BLUE
154 #undef RGB_PIXELSIZE
155 #undef rgb_ycc_convert_internal
156 #undef rgb_gray_convert_internal
157 #undef rgb_rgb_convert_internal
158 
159 #define RGB_RED EXT_XBGR_RED
160 #define RGB_GREEN EXT_XBGR_GREEN
161 #define RGB_BLUE EXT_XBGR_BLUE
162 #define RGB_PIXELSIZE EXT_XBGR_PIXELSIZE
163 #define rgb_ycc_convert_internal extxbgr_ycc_convert_internal
164 #define rgb_gray_convert_internal extxbgr_gray_convert_internal
165 #define rgb_rgb_convert_internal extxbgr_rgb_convert_internal
166 #include "jccolext.c"
167 #undef RGB_RED
168 #undef RGB_GREEN
169 #undef RGB_BLUE
170 #undef RGB_PIXELSIZE
171 #undef rgb_ycc_convert_internal
172 #undef rgb_gray_convert_internal
173 #undef rgb_rgb_convert_internal
174 
175 #define RGB_RED EXT_XRGB_RED
176 #define RGB_GREEN EXT_XRGB_GREEN
177 #define RGB_BLUE EXT_XRGB_BLUE
178 #define RGB_PIXELSIZE EXT_XRGB_PIXELSIZE
179 #define rgb_ycc_convert_internal extxrgb_ycc_convert_internal
180 #define rgb_gray_convert_internal extxrgb_gray_convert_internal
181 #define rgb_rgb_convert_internal extxrgb_rgb_convert_internal
182 #include "jccolext.c"
183 #undef RGB_RED
184 #undef RGB_GREEN
185 #undef RGB_BLUE
186 #undef RGB_PIXELSIZE
187 #undef rgb_ycc_convert_internal
188 #undef rgb_gray_convert_internal
189 #undef rgb_rgb_convert_internal
190 
191 
192 /*
193  * Initialize for RGB->YCC colorspace conversion.
194  */
195 
196 METHODDEF(void)
rgb_ycc_start(j_compress_ptr cinfo)197 rgb_ycc_start (j_compress_ptr cinfo)
198 {
199   my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert;
200   INT32 * rgb_ycc_tab;
201   INT32 i;
202 
203   /* Allocate and fill in the conversion tables. */
204   cconvert->rgb_ycc_tab = rgb_ycc_tab = (INT32 *)
205     (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
206                                 (TABLE_SIZE * sizeof(INT32)));
207 
208   for (i = 0; i <= MAXJSAMPLE; i++) {
209     rgb_ycc_tab[i+R_Y_OFF] = FIX(0.29900) * i;
210     rgb_ycc_tab[i+G_Y_OFF] = FIX(0.58700) * i;
211     rgb_ycc_tab[i+B_Y_OFF] = FIX(0.11400) * i     + ONE_HALF;
212     rgb_ycc_tab[i+R_CB_OFF] = (-FIX(0.16874)) * i;
213     rgb_ycc_tab[i+G_CB_OFF] = (-FIX(0.33126)) * i;
214     /* We use a rounding fudge-factor of 0.5-epsilon for Cb and Cr.
215      * This ensures that the maximum output will round to MAXJSAMPLE
216      * not MAXJSAMPLE+1, and thus that we don't have to range-limit.
217      */
218     rgb_ycc_tab[i+B_CB_OFF] = FIX(0.50000) * i    + CBCR_OFFSET + ONE_HALF-1;
219 /*  B=>Cb and R=>Cr tables are the same
220     rgb_ycc_tab[i+R_CR_OFF] = FIX(0.50000) * i    + CBCR_OFFSET + ONE_HALF-1;
221 */
222     rgb_ycc_tab[i+G_CR_OFF] = (-FIX(0.41869)) * i;
223     rgb_ycc_tab[i+B_CR_OFF] = (-FIX(0.08131)) * i;
224   }
225 }
226 
227 
228 /*
229  * Convert some rows of samples to the JPEG colorspace.
230  */
231 
232 METHODDEF(void)
rgb_ycc_convert(j_compress_ptr cinfo,JSAMPARRAY input_buf,JSAMPIMAGE output_buf,JDIMENSION output_row,int num_rows)233 rgb_ycc_convert (j_compress_ptr cinfo,
234                  JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
235                  JDIMENSION output_row, int num_rows)
236 {
237   switch (cinfo->in_color_space) {
238     case JCS_EXT_RGB:
239       extrgb_ycc_convert_internal(cinfo, input_buf, output_buf, output_row,
240                                   num_rows);
241       break;
242     case JCS_EXT_RGBX:
243     case JCS_EXT_RGBA:
244       extrgbx_ycc_convert_internal(cinfo, input_buf, output_buf, output_row,
245                                    num_rows);
246       break;
247     case JCS_EXT_BGR:
248       extbgr_ycc_convert_internal(cinfo, input_buf, output_buf, output_row,
249                                   num_rows);
250       break;
251     case JCS_EXT_BGRX:
252     case JCS_EXT_BGRA:
253       extbgrx_ycc_convert_internal(cinfo, input_buf, output_buf, output_row,
254                                    num_rows);
255       break;
256     case JCS_EXT_XBGR:
257     case JCS_EXT_ABGR:
258       extxbgr_ycc_convert_internal(cinfo, input_buf, output_buf, output_row,
259                                    num_rows);
260       break;
261     case JCS_EXT_XRGB:
262     case JCS_EXT_ARGB:
263       extxrgb_ycc_convert_internal(cinfo, input_buf, output_buf, output_row,
264                                    num_rows);
265       break;
266     default:
267       rgb_ycc_convert_internal(cinfo, input_buf, output_buf, output_row,
268                                num_rows);
269       break;
270   }
271 }
272 
273 
274 /**************** Cases other than RGB -> YCbCr **************/
275 
276 
277 /*
278  * Convert some rows of samples to the JPEG colorspace.
279  */
280 
281 METHODDEF(void)
rgb_gray_convert(j_compress_ptr cinfo,JSAMPARRAY input_buf,JSAMPIMAGE output_buf,JDIMENSION output_row,int num_rows)282 rgb_gray_convert (j_compress_ptr cinfo,
283                   JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
284                   JDIMENSION output_row, int num_rows)
285 {
286   switch (cinfo->in_color_space) {
287     case JCS_EXT_RGB:
288       extrgb_gray_convert_internal(cinfo, input_buf, output_buf, output_row,
289                                    num_rows);
290       break;
291     case JCS_EXT_RGBX:
292     case JCS_EXT_RGBA:
293       extrgbx_gray_convert_internal(cinfo, input_buf, output_buf, output_row,
294                                     num_rows);
295       break;
296     case JCS_EXT_BGR:
297       extbgr_gray_convert_internal(cinfo, input_buf, output_buf, output_row,
298                                    num_rows);
299       break;
300     case JCS_EXT_BGRX:
301     case JCS_EXT_BGRA:
302       extbgrx_gray_convert_internal(cinfo, input_buf, output_buf, output_row,
303                                     num_rows);
304       break;
305     case JCS_EXT_XBGR:
306     case JCS_EXT_ABGR:
307       extxbgr_gray_convert_internal(cinfo, input_buf, output_buf, output_row,
308                                     num_rows);
309       break;
310     case JCS_EXT_XRGB:
311     case JCS_EXT_ARGB:
312       extxrgb_gray_convert_internal(cinfo, input_buf, output_buf, output_row,
313                                     num_rows);
314       break;
315     default:
316       rgb_gray_convert_internal(cinfo, input_buf, output_buf, output_row,
317                                 num_rows);
318       break;
319   }
320 }
321 
322 
323 /*
324  * Extended RGB to plain RGB conversion
325  */
326 
327 METHODDEF(void)
rgb_rgb_convert(j_compress_ptr cinfo,JSAMPARRAY input_buf,JSAMPIMAGE output_buf,JDIMENSION output_row,int num_rows)328 rgb_rgb_convert (j_compress_ptr cinfo,
329                   JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
330                   JDIMENSION output_row, int num_rows)
331 {
332   switch (cinfo->in_color_space) {
333     case JCS_EXT_RGB:
334       extrgb_rgb_convert_internal(cinfo, input_buf, output_buf, output_row,
335                                   num_rows);
336       break;
337     case JCS_EXT_RGBX:
338     case JCS_EXT_RGBA:
339       extrgbx_rgb_convert_internal(cinfo, input_buf, output_buf, output_row,
340                                    num_rows);
341       break;
342     case JCS_EXT_BGR:
343       extbgr_rgb_convert_internal(cinfo, input_buf, output_buf, output_row,
344                                   num_rows);
345       break;
346     case JCS_EXT_BGRX:
347     case JCS_EXT_BGRA:
348       extbgrx_rgb_convert_internal(cinfo, input_buf, output_buf, output_row,
349                                    num_rows);
350       break;
351     case JCS_EXT_XBGR:
352     case JCS_EXT_ABGR:
353       extxbgr_rgb_convert_internal(cinfo, input_buf, output_buf, output_row,
354                                    num_rows);
355       break;
356     case JCS_EXT_XRGB:
357     case JCS_EXT_ARGB:
358       extxrgb_rgb_convert_internal(cinfo, input_buf, output_buf, output_row,
359                                    num_rows);
360       break;
361     default:
362       rgb_rgb_convert_internal(cinfo, input_buf, output_buf, output_row,
363                                num_rows);
364       break;
365   }
366 }
367 
368 
369 /*
370  * Convert some rows of samples to the JPEG colorspace.
371  * This version handles Adobe-style CMYK->YCCK conversion,
372  * where we convert R=1-C, G=1-M, and B=1-Y to YCbCr using the same
373  * conversion as above, while passing K (black) unchanged.
374  * We assume rgb_ycc_start has been called.
375  */
376 
377 METHODDEF(void)
cmyk_ycck_convert(j_compress_ptr cinfo,JSAMPARRAY input_buf,JSAMPIMAGE output_buf,JDIMENSION output_row,int num_rows)378 cmyk_ycck_convert (j_compress_ptr cinfo,
379                    JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
380                    JDIMENSION output_row, int num_rows)
381 {
382   my_cconvert_ptr cconvert = (my_cconvert_ptr) cinfo->cconvert;
383   register int r, g, b;
384   register INT32 * ctab = cconvert->rgb_ycc_tab;
385   register JSAMPROW inptr;
386   register JSAMPROW outptr0, outptr1, outptr2, outptr3;
387   register JDIMENSION col;
388   JDIMENSION num_cols = cinfo->image_width;
389 
390   while (--num_rows >= 0) {
391     inptr = *input_buf++;
392     outptr0 = output_buf[0][output_row];
393     outptr1 = output_buf[1][output_row];
394     outptr2 = output_buf[2][output_row];
395     outptr3 = output_buf[3][output_row];
396     output_row++;
397     for (col = 0; col < num_cols; col++) {
398       r = MAXJSAMPLE - GETJSAMPLE(inptr[0]);
399       g = MAXJSAMPLE - GETJSAMPLE(inptr[1]);
400       b = MAXJSAMPLE - GETJSAMPLE(inptr[2]);
401       /* K passes through as-is */
402       outptr3[col] = inptr[3];  /* don't need GETJSAMPLE here */
403       inptr += 4;
404       /* If the inputs are 0..MAXJSAMPLE, the outputs of these equations
405        * must be too; we do not need an explicit range-limiting operation.
406        * Hence the value being shifted is never negative, and we don't
407        * need the general RIGHT_SHIFT macro.
408        */
409       /* Y */
410       outptr0[col] = (JSAMPLE)
411                 ((ctab[r+R_Y_OFF] + ctab[g+G_Y_OFF] + ctab[b+B_Y_OFF])
412                  >> SCALEBITS);
413       /* Cb */
414       outptr1[col] = (JSAMPLE)
415                 ((ctab[r+R_CB_OFF] + ctab[g+G_CB_OFF] + ctab[b+B_CB_OFF])
416                  >> SCALEBITS);
417       /* Cr */
418       outptr2[col] = (JSAMPLE)
419                 ((ctab[r+R_CR_OFF] + ctab[g+G_CR_OFF] + ctab[b+B_CR_OFF])
420                  >> SCALEBITS);
421     }
422   }
423 }
424 
425 
426 /*
427  * Convert some rows of samples to the JPEG colorspace.
428  * This version handles grayscale output with no conversion.
429  * The source can be either plain grayscale or YCbCr (since Y == gray).
430  */
431 
432 METHODDEF(void)
grayscale_convert(j_compress_ptr cinfo,JSAMPARRAY input_buf,JSAMPIMAGE output_buf,JDIMENSION output_row,int num_rows)433 grayscale_convert (j_compress_ptr cinfo,
434                    JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
435                    JDIMENSION output_row, int num_rows)
436 {
437   register JSAMPROW inptr;
438   register JSAMPROW outptr;
439   register JDIMENSION col;
440   JDIMENSION num_cols = cinfo->image_width;
441   int instride = cinfo->input_components;
442 
443   while (--num_rows >= 0) {
444     inptr = *input_buf++;
445     outptr = output_buf[0][output_row];
446     output_row++;
447     for (col = 0; col < num_cols; col++) {
448       outptr[col] = inptr[0];   /* don't need GETJSAMPLE() here */
449       inptr += instride;
450     }
451   }
452 }
453 
454 
455 /*
456  * Convert some rows of samples to the JPEG colorspace.
457  * This version handles multi-component colorspaces without conversion.
458  * We assume input_components == num_components.
459  */
460 
461 METHODDEF(void)
null_convert(j_compress_ptr cinfo,JSAMPARRAY input_buf,JSAMPIMAGE output_buf,JDIMENSION output_row,int num_rows)462 null_convert (j_compress_ptr cinfo,
463               JSAMPARRAY input_buf, JSAMPIMAGE output_buf,
464               JDIMENSION output_row, int num_rows)
465 {
466   register JSAMPROW inptr;
467   register JSAMPROW outptr, outptr0, outptr1, outptr2, outptr3;
468   register JDIMENSION col;
469   register int ci;
470   int nc = cinfo->num_components;
471   JDIMENSION num_cols = cinfo->image_width;
472 
473   if (nc == 3) {
474     while (--num_rows >= 0) {
475       inptr = *input_buf++;
476       outptr0 = output_buf[0][output_row];
477       outptr1 = output_buf[1][output_row];
478       outptr2 = output_buf[2][output_row];
479       output_row++;
480       for (col = 0; col < num_cols; col++) {
481         outptr0[col] = *inptr++;
482         outptr1[col] = *inptr++;
483         outptr2[col] = *inptr++;
484       }
485     }
486   } else if (nc == 4) {
487     while (--num_rows >= 0) {
488       inptr = *input_buf++;
489       outptr0 = output_buf[0][output_row];
490       outptr1 = output_buf[1][output_row];
491       outptr2 = output_buf[2][output_row];
492       outptr3 = output_buf[3][output_row];
493       output_row++;
494       for (col = 0; col < num_cols; col++) {
495         outptr0[col] = *inptr++;
496         outptr1[col] = *inptr++;
497         outptr2[col] = *inptr++;
498         outptr3[col] = *inptr++;
499       }
500     }
501   } else {
502     while (--num_rows >= 0) {
503       /* It seems fastest to make a separate pass for each component. */
504       for (ci = 0; ci < nc; ci++) {
505         inptr = *input_buf;
506         outptr = output_buf[ci][output_row];
507         for (col = 0; col < num_cols; col++) {
508           outptr[col] = inptr[ci]; /* don't need GETJSAMPLE() here */
509           inptr += nc;
510         }
511       }
512       input_buf++;
513       output_row++;
514     }
515   }
516 }
517 
518 
519 /*
520  * Empty method for start_pass.
521  */
522 
523 METHODDEF(void)
null_method(j_compress_ptr cinfo)524 null_method (j_compress_ptr cinfo)
525 {
526   /* no work needed */
527 }
528 
529 
530 /*
531  * Module initialization routine for input colorspace conversion.
532  */
533 
534 GLOBAL(void)
jinit_color_converter(j_compress_ptr cinfo)535 jinit_color_converter (j_compress_ptr cinfo)
536 {
537   my_cconvert_ptr cconvert;
538 
539   cconvert = (my_cconvert_ptr)
540     (*cinfo->mem->alloc_small) ((j_common_ptr) cinfo, JPOOL_IMAGE,
541                                 sizeof(my_color_converter));
542   cinfo->cconvert = (struct jpeg_color_converter *) cconvert;
543   /* set start_pass to null method until we find out differently */
544   cconvert->pub.start_pass = null_method;
545 
546   /* Make sure input_components agrees with in_color_space */
547   switch (cinfo->in_color_space) {
548   case JCS_GRAYSCALE:
549     if (cinfo->input_components != 1)
550       ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE);
551     break;
552 
553   case JCS_RGB:
554   case JCS_EXT_RGB:
555   case JCS_EXT_RGBX:
556   case JCS_EXT_BGR:
557   case JCS_EXT_BGRX:
558   case JCS_EXT_XBGR:
559   case JCS_EXT_XRGB:
560   case JCS_EXT_RGBA:
561   case JCS_EXT_BGRA:
562   case JCS_EXT_ABGR:
563   case JCS_EXT_ARGB:
564     if (cinfo->input_components != rgb_pixelsize[cinfo->in_color_space])
565       ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE);
566     break;
567 
568   case JCS_YCbCr:
569     if (cinfo->input_components != 3)
570       ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE);
571     break;
572 
573   case JCS_CMYK:
574   case JCS_YCCK:
575     if (cinfo->input_components != 4)
576       ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE);
577     break;
578 
579   default:                      /* JCS_UNKNOWN can be anything */
580     if (cinfo->input_components < 1)
581       ERREXIT(cinfo, JERR_BAD_IN_COLORSPACE);
582     break;
583   }
584 
585   /* Check num_components, set conversion method based on requested space */
586   switch (cinfo->jpeg_color_space) {
587   case JCS_GRAYSCALE:
588     if (cinfo->num_components != 1)
589       ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
590     if (cinfo->in_color_space == JCS_GRAYSCALE)
591       cconvert->pub.color_convert = grayscale_convert;
592     else if (cinfo->in_color_space == JCS_RGB ||
593              cinfo->in_color_space == JCS_EXT_RGB ||
594              cinfo->in_color_space == JCS_EXT_RGBX ||
595              cinfo->in_color_space == JCS_EXT_BGR ||
596              cinfo->in_color_space == JCS_EXT_BGRX ||
597              cinfo->in_color_space == JCS_EXT_XBGR ||
598              cinfo->in_color_space == JCS_EXT_XRGB ||
599              cinfo->in_color_space == JCS_EXT_RGBA ||
600              cinfo->in_color_space == JCS_EXT_BGRA ||
601              cinfo->in_color_space == JCS_EXT_ABGR ||
602              cinfo->in_color_space == JCS_EXT_ARGB) {
603       if (jsimd_can_rgb_gray())
604         cconvert->pub.color_convert = jsimd_rgb_gray_convert;
605       else {
606         cconvert->pub.start_pass = rgb_ycc_start;
607         cconvert->pub.color_convert = rgb_gray_convert;
608       }
609     } else if (cinfo->in_color_space == JCS_YCbCr)
610       cconvert->pub.color_convert = grayscale_convert;
611     else
612       ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
613     break;
614 
615   case JCS_RGB:
616     if (cinfo->num_components != 3)
617       ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
618     if (rgb_red[cinfo->in_color_space] == 0 &&
619         rgb_green[cinfo->in_color_space] == 1 &&
620         rgb_blue[cinfo->in_color_space] == 2 &&
621         rgb_pixelsize[cinfo->in_color_space] == 3) {
622 #if defined(__mips__)
623       if (jsimd_c_can_null_convert())
624         cconvert->pub.color_convert = jsimd_c_null_convert;
625       else
626 #endif
627         cconvert->pub.color_convert = null_convert;
628     } else if (cinfo->in_color_space == JCS_RGB ||
629                cinfo->in_color_space == JCS_EXT_RGB ||
630                cinfo->in_color_space == JCS_EXT_RGBX ||
631                cinfo->in_color_space == JCS_EXT_BGR ||
632                cinfo->in_color_space == JCS_EXT_BGRX ||
633                cinfo->in_color_space == JCS_EXT_XBGR ||
634                cinfo->in_color_space == JCS_EXT_XRGB ||
635                cinfo->in_color_space == JCS_EXT_RGBA ||
636                cinfo->in_color_space == JCS_EXT_BGRA ||
637                cinfo->in_color_space == JCS_EXT_ABGR ||
638                cinfo->in_color_space == JCS_EXT_ARGB)
639       cconvert->pub.color_convert = rgb_rgb_convert;
640     else
641       ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
642     break;
643 
644   case JCS_YCbCr:
645     if (cinfo->num_components != 3)
646       ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
647     if (cinfo->in_color_space == JCS_RGB ||
648         cinfo->in_color_space == JCS_EXT_RGB ||
649         cinfo->in_color_space == JCS_EXT_RGBX ||
650         cinfo->in_color_space == JCS_EXT_BGR ||
651         cinfo->in_color_space == JCS_EXT_BGRX ||
652         cinfo->in_color_space == JCS_EXT_XBGR ||
653         cinfo->in_color_space == JCS_EXT_XRGB ||
654         cinfo->in_color_space == JCS_EXT_RGBA ||
655         cinfo->in_color_space == JCS_EXT_BGRA ||
656         cinfo->in_color_space == JCS_EXT_ABGR ||
657         cinfo->in_color_space == JCS_EXT_ARGB) {
658       if (jsimd_can_rgb_ycc())
659         cconvert->pub.color_convert = jsimd_rgb_ycc_convert;
660       else {
661         cconvert->pub.start_pass = rgb_ycc_start;
662         cconvert->pub.color_convert = rgb_ycc_convert;
663       }
664     } else if (cinfo->in_color_space == JCS_YCbCr) {
665 #if defined(__mips__)
666       if (jsimd_c_can_null_convert())
667         cconvert->pub.color_convert = jsimd_c_null_convert;
668       else
669 #endif
670         cconvert->pub.color_convert = null_convert;
671     } else
672       ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
673     break;
674 
675   case JCS_CMYK:
676     if (cinfo->num_components != 4)
677       ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
678     if (cinfo->in_color_space == JCS_CMYK) {
679 #if defined(__mips__)
680       if (jsimd_c_can_null_convert())
681         cconvert->pub.color_convert = jsimd_c_null_convert;
682       else
683 #endif
684         cconvert->pub.color_convert = null_convert;
685     } else
686       ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
687     break;
688 
689   case JCS_YCCK:
690     if (cinfo->num_components != 4)
691       ERREXIT(cinfo, JERR_BAD_J_COLORSPACE);
692     if (cinfo->in_color_space == JCS_CMYK) {
693       cconvert->pub.start_pass = rgb_ycc_start;
694       cconvert->pub.color_convert = cmyk_ycck_convert;
695     } else if (cinfo->in_color_space == JCS_YCCK) {
696 #if defined(__mips__)
697       if (jsimd_c_can_null_convert())
698         cconvert->pub.color_convert = jsimd_c_null_convert;
699       else
700 #endif
701         cconvert->pub.color_convert = null_convert;
702     } else
703       ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
704     break;
705 
706   default:                      /* allow null conversion of JCS_UNKNOWN */
707     if (cinfo->jpeg_color_space != cinfo->in_color_space ||
708         cinfo->num_components != cinfo->input_components)
709       ERREXIT(cinfo, JERR_CONVERSION_NOTIMPL);
710 #if defined(__mips__)
711     if (jsimd_c_can_null_convert())
712       cconvert->pub.color_convert = jsimd_c_null_convert;
713     else
714 #endif
715       cconvert->pub.color_convert = null_convert;
716     break;
717   }
718 }
719