aboutsummaryrefslogtreecommitdiffstats
path: root/src/lib/libgamma-facade.c.gpp
blob: 8d10c5dd8c36e41fe1d307b4ae0507ec753e0ddf (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
/* -*- c -*- */
/**
 * libgamma -- Display server abstraction layer for gamma ramp adjustments
 * Copyright (C) 2014, 2015  Mattias Andrée (maandree@member.fsf.org)
 * 
 * This library is free software: you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation, either version 3 of the License, or
 * (at your option) any later version.
 * 
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 * 
 * You should have received a copy of the GNU General Public License
 * along with this library.  If not, see <http://www.gnu.org/licenses/>.
 */
#include "libgamma-facade.h"

#include "libgamma-error.h"
#include "libgamma-method.h"
#include "gamma-helper.h"


/* Initialise the general preprocessor. */
$>cd src/extract
$>export PATH=".:${PATH}"

/* Some general preprocessor we will use frequently. */
$<
get-methods ()
{ ./libgamma-method-extract --list --method | cut -d _ -f 1,2 --complement
}
lowercase ()
{ echo "$*" | sed -e y/QWERTYUIOPASDFGHJKLZXCVBNM/qwertyuiopasdfghjklzxcvbnm/ | sed -e s:core_graphics:cg:g
}
$>

/* Include all adjustment methods that
   are enabled at compile-time. */
$>for method in $(get-methods); do
#ifdef HAVE_LIBGAMMA_METHOD_${method}
# include "gamma-$(lowercase $method | sed -e s:_:-:g).h"
# ifndef HAVE_LIBGAMMA_METHODS
#  define HAVE_LIBGAMMA_METHODS
# endif
#endif
$>done

#include <unistd.h>
#include <stddef.h>
#include <stdint.h>
#include <stdlib.h>
#include <string.h>
#include <errno.h>


/* Some things to reduce warnings when we do
   not have any adjustment methods enabled. */
#ifndef HAVE_LIBGAMMA_METHODS
# define HAVE_NO_LIBGAMMA_METHODS
# ifdef __GCC__
#  pragma GCC diagnostic push
#  pragma GCC diagnostic ignored "-Wsuggest-attribute=const"
# endif
#endif



#ifdef HAVE_LIBGAMMA_METHODS
# ifdef HAVE_LIBGAMMA_METHOD_LINUX_DRM
/**
 * Test whether a file descriptor refers to a VT.
 * 
 * @param   fd  The file descriptor.
 * @return      Whether the file descriptor refers to a VT.
 */
static int libgamma_is_vt_proper(int fd)
{
  char buf[32];
  char digit0;
  
  /* Get TTY. */
  if (ttyname_r(fd, buf, sizeof(buf) / sizeof(char)))
    return 0;
  
  /* Validate TTY path. */
  if (strstr(buf, "/dev/tty") != buf)
    return 0;
  
  /* Validate TTY name. */
  digit0 = buf[strlen("/dev/tty")];
  return ('1' <= digit0) && (digit0 <= '9');
}
# endif


/**
 * Test the availability of an adjustment method.
 * 
 * @param  method     The adjustment method.
 * @param  operation  Allowed values:
 *                      0: Pass if the environment suggests it will work but is not fake.
 *                      1: Pass if the environment suggests it will work.
 *                      2: Pass if real and not fake.
 *                      3: Pass if real.
 *                      4: Always pass.
 *                    Other values invoke undefined behaviour.
 * @return            Whether the test passed.
 */
static int libgamma_list_method_test(int method, int operation)
{
  libgamma_method_capabilities_t caps;
  libgamma_method_capabilities(&caps, method);
  
  switch (operation)
    {
    case 0:
      /* Methods that the environment suggests will work, excluding fake. */
      if (caps.fake)
	return 0;
      /* Fall through. */
      
    case 1:
      /* Methods that the environment suggests will work, including fake. */
      if (caps.real == 0)
	return 0;
#ifdef HAVE_LIBGAMMA_METHOD_LINUX_DRM
      if (method == LIBGAMMA_METHOD_LINUX_DRM)
	return libgamma_is_vt_proper(STDIN_FILENO) ||
	       libgamma_is_vt_proper(STDOUT_FILENO) ||
	       libgamma_is_vt_proper(STDERR_FILENO);
#endif
#ifdef HAVE_LIBGAMMA_METHOD_DUMMY
      if (method == LIBGAMMA_METHOD_DUMMY)
	return 0;
#endif
      return caps.default_site_known;
      
    case 2:
      /* All real non-fake methods. */
      return caps.real && (caps.fake == 0);
      
    case 3:
      /* All real methods. */
      return caps.real;
      
    default:
      /* All methods. */
      return 1;
    }
}
#endif


/**
 * List available adjustment methods by their order of preference based on the environment.
 * 
 * @param  methods    Output array of methods, should be able to hold `LIBGAMMA_METHOD_COUNT` elements.
 * @param  buf_size   The number of elements that fits in `methods`, it should be `LIBGAMMA_METHOD_COUNT`,
 *                    This is used to avoid writing outside the output buffer if this library adds new
 *                    adjustment methods without the users of the library recompiling.
 * @param  operation  Allowed values:
 *                      0: Methods that the environment suggests will work, excluding fake.
 *                      1: Methods that the environment suggests will work, including fake.
 *                      2: All real non-fake methods.
 *                      3: All real methods.
 *                      4: All methods.
 *                    Other values invoke undefined behaviour.
 * @return            The number of element that have been stored in `methods`, or should
 *                    have been stored if the buffer was large enough.
 */
size_t libgamma_list_methods(int* restrict methods, size_t buf_size, int operation)
{
#ifdef HAVE_NO_LIBGAMMA_METHODS
  (void) methods;
  (void) buf_size;
  (void) operation;
  return 0;
#else
  size_t n = 0, len;
  int included[LIBGAMMA_METHOD_COUNT];
  char* begin;
  char* end;
  
  memset(included, 0, LIBGAMMA_METHOD_COUNT * sizeof(int));
  begin = getenv("PREFERRED_DISPLAY");
  while (begin && *begin)
    {
      end = strchr(begin, ' ');
      len = (size_t)(end - begin);
      if (len == 0);
#ifdef HAVE_LIBGAMMA_METHOD_WAYLAND
      else if ((len == 7) && !strncmp(begin, "wayland", len)) /* 7 is strlen("wayland") */
	{
	  if (libgamma_list_method_test(LIBGAMMA_METHOD_WAYLAND, operation) && (n++ < buf_size))
	    methods[n - 1] = LIBGAMMA_METHOD_WAYLAND, included[methods[n - 1]] = 1;
	}
#endif
#if defined(HAVE_LIBGAMMA_METHOD_X_RANDR) || defined(HAVE_LIBGAMMA_METHOD_X_VIDMODE)
      else if ((len == 3) && !strncmp(begin, "x11", len)) /* 3 is strlen("x11") */
	{
# ifdef HAVE_LIBGAMMA_METHOD_X_RANDR
	  if (libgamma_list_method_test(LIBGAMMA_METHOD_X_RANDR, operation) && (n++ < buf_size))
	    methods[n - 1] = LIBGAMMA_METHOD_X_RANDR, included[methods[n - 1]] = 1;
# endif
# ifdef HAVE_LIBGAMMA_METHOD_X_VIDMODE
	  if (libgamma_list_method_test(LIBGAMMA_METHOD_X_VIDMODE, operation) && (n++ < buf_size))
	    methods[n - 1] = LIBGAMMA_METHOD_X_VIDMODE, included[methods[n - 1]] = 1;
# endif
	}
#endif
      begin = end + 1;
    }
  
$>for method in $(get-methods); do
#ifdef HAVE_LIBGAMMA_METHOD_${method}
  if (included[LIBGAMMA_METHOD_${method}] == 0)
    if (libgamma_list_method_test(LIBGAMMA_METHOD_${method}, operation) && (n++ < buf_size))
      methods[n - 1] = LIBGAMMA_METHOD_${method};
#endif
$>done
  
  return n;
#endif
}


/**
 * Check whether an adjustment method is available, non-existing (invalid) methods will be
 * identified as not available under the rationale that the library may be out of date.
 * 
 * @param   method  The adjustment method.
 * @return          Whether the adjustment method is available.
 */
int libgamma_is_method_available(int method)
{
#ifdef HAVE_NO_LIBGAMMA_METHODS
  (void) method;
  return 0;
#else
  switch (method)
    {
$>for method in $(get-methods); do
#ifdef HAVE_LIBGAMMA_METHOD_${method}
    case LIBGAMMA_METHOD_${method}:
#endif
$>done
      return 1;
      
    default:
      return 0;
    }
#endif
}


/**
 * Call the adjustment method's implementation of the called function.
 * 
 * @param  1  The adjustment method, you may use `.` instead of `->` when resolving it.
 * @param  2  `return` if the function returns a value, `break` otherwise.
 * @param  3  The base name of the function to call, that is, the name of the function
 *            this is expended into without the libgamma namespace prefix.
 * @param  *  The function's parameters.
 */
$<switch ()
$>{
  /* Read out macro's parameters. */
$<method="${1//./->}"
  ctrl=$2
  fun=$3
  shift 3
  params="$*"
$>params="${params// /, }"
  
  switch (${method})
    {
$>for adjmethod in $(get-methods); do
#ifdef HAVE_LIBGAMMA_METHOD_${adjmethod}
    case LIBGAMMA_METHOD_${adjmethod}:
      /* Call the adjustment method's implementation, either
	 return or break after it depending on macro parameter's. */
$>[ $ctrl = return ] &&
      return
      libgamma_$(lowercase $adjmethod)_${fun}(${params});
$>[ ! $ctrl = return ] &&
      break;
#endif
$>done
    
    default:
      /* If the adjustment method does not exists, either return
	 that error, or do nothing because the function this is
	 expanded into does return errors. */
$>if [ $ctrl = return ]; then
      return LIBGAMMA_NO_SUCH_ADJUSTMENT_METHOD;
$>else
      /* Method does not exists/excluded at compile-time.
	 We will assume that this is not done... */
      break;
$>fi
    }
$>}


/**
 * Return the capabilities of an adjustment method.
 * 
 * @param  this    The data structure to fill with the method's capabilities.
 * @param  method  The adjustment method (display server and protocol.)
 */
void libgamma_method_capabilities(libgamma_method_capabilities_t* restrict this, int method)
{
  memset(this, 0, sizeof(libgamma_method_capabilities_t));
$>switch method break method_capabilities this
}


/**
 * Return the default site for an adjustment method.
 * 
 * @param   method  The adjustment method (display server and protocol.)
 * @return          The default site, `NULL` if it cannot be determined or
 *                  if multiple sites are not supported by the adjustment
 *                  method. This value should not be `free`:d.
 */
char* libgamma_method_default_site(int method)
{
  const char* restrict var = libgamma_method_default_site_variable(method);
  char* restrict env;
  
  /* Return `NULL` there is not variable to read. */
  if (var == NULL)
    return NULL;
  
  /* Read the variable. */
  env = getenv(var);
  /* Return `NULL` if it does not exist (or is empty). */
  if ((env == NULL) || (*env == '\0'))
    return NULL;
  
  /* Return the variable's value. */
  return env;
}


/**
 * Return the default variable that determines
 * the default site for an adjustment method.
 * 
 * @param   method  The adjustment method (display server and protocol.)
 * @return          The environ variables that is used to determine the
 *                  default site. `NULL` if there is none, that is, if
 *                  the method does not support multiple sites.
 *                  This value should not be `free`:d.
 */
const char* libgamma_method_default_site_variable(int method)
{
  switch (method)
    {
#ifdef HAVE_LIBGAMMA_METHOD_X_RANDR
    case LIBGAMMA_METHOD_X_RANDR:
      return "DISPLAY";
#endif
#ifdef HAVE_LIBGAMMA_METHOD_X_VIDMODE
    case LIBGAMMA_METHOD_X_VIDMODE:
      return "DISPLAY";
#endif
#ifdef HAVE_LIBGAMMA_METHOD_WAYLAND
    case LIBGAMMA_METHOD_WAYLAND:
      return "WAYLAND_DISPLAY";
#endif
    default:
      return NULL;
    }
}


/**
 * Initialise an allocated site state.
 * 
 * @param   this    The site state to initialise.
 * @param   method  The adjustment method (display server and protocol.)
 * @param   site    The site identifier, unless it is `NULL` it must a
 *                  `free`:able. One the state is destroyed the library
 *                  will attempt to free it. There you should not free
 *                  it yourself, and it must not be a string constant
 *                  or allocated on the stack. Note however that it will
 *                  not be `free`:d if this function fails.
 * @return          Zero on success, otherwise (negative) the value of an
 *                  error identifier provided by this library.
 */
int libgamma_site_initialise(libgamma_site_state_t* restrict this,
			     int method, char* restrict site)
{
  this->method = method;
  this->site = site;
$>switch method return site_initialise this site
}


/**
 * Release all resources held by a site state.
 * 
 * @param  this  The site state.
 */
void libgamma_site_destroy(libgamma_site_state_t* restrict this)
{
$>switch this.method break site_destroy this
  free(this->site);
}


/**
 * Release all resources held by a site state
 * and free the site state pointer.
 * 
 * @param  this  The site state.
 */
void libgamma_site_free(libgamma_site_state_t* restrict this)
{
  libgamma_site_destroy(this);
  free(this);
}


/**
 * Restore the gamma ramps all CRTC:s with a site to the system settings.
 * 
 * @param   this  The site state.
 * @return        Zero on success, otherwise (negative) the value of an
 *                error identifier provided by this library.
 */
int libgamma_site_restore(libgamma_site_state_t* restrict this)
{
$>switch this.method return site_restore this
}



/**
 * Initialise an allocated partition state.
 * 
 * @param   this       The partition state to initialise.
 * @param   site       The site state for the site that the partition belongs to.
 * @param   partition  The index of the partition within the site.
 * @return             Zero on success, otherwise (negative) the value of an
 *                     error identifier provided by this library.
 */
int libgamma_partition_initialise(libgamma_partition_state_t* restrict this,
				  libgamma_site_state_t* restrict site, size_t partition)
{
  this->site = site;
  this->partition = partition;
$>switch site.method return partition_initialise this site partition
}


/**
 * Release all resources held by a partition state.
 * 
 * @param  this  The partition state.
 */
void libgamma_partition_destroy(libgamma_partition_state_t* restrict this)
{
$>switch this.site.method break partition_destroy this
}


/**
 * Release all resources held by a partition state
 * and free the partition state pointer.
 * 
 * @param  this  The partition state.
 */
void libgamma_partition_free(libgamma_partition_state_t* restrict this)
{
  libgamma_partition_destroy(this);
  free(this);
}


/**
 * Restore the gamma ramps all CRTC:s with a partition to the system settings.
 * 
 * @param   this  The partition state.
 * @return        Zero on success, otherwise (negative) the value of an
 *                error identifier provided by this library.
 */
int libgamma_partition_restore(libgamma_partition_state_t* restrict this)
{
$>switch this.site.method return partition_restore this
}



/**
 * Initialise an allocated CRTC state.
 * 
 * @param   this       The CRTC state to initialise.
 * @param   partition  The partition state for the partition that the CRTC belongs to.
 * @param   crtc       The index of the CRTC within the partition.
 * @return             Zero on success, otherwise (negative) the value of an
 *                     error identifier provided by this library.
 */
int libgamma_crtc_initialise(libgamma_crtc_state_t* restrict this,
			     libgamma_partition_state_t* restrict partition, size_t crtc)
{
  this->partition = partition;
  this->crtc = crtc;
$>switch partition.site.method return crtc_initialise this partition crtc
}


/**
 * Release all resources held by a CRTC state.
 * 
 * @param  this  The CRTC state.
 */
void libgamma_crtc_destroy(libgamma_crtc_state_t* restrict this)
{
$>switch this.partition.site.method break crtc_destroy this
}


/**
 * Release all resources held by a CRTC state
 * and free the CRTC state pointer.
 * 
 * @param  this  The CRTC state.
 */
void libgamma_crtc_free(libgamma_crtc_state_t* restrict this)
{
  libgamma_crtc_destroy(this);
  free(this);
}


/**
 * Restore the gamma ramps for a CRTC to the system settings for that CRTC.
 * 
 * @param   this  The CRTC state.
 * @return        Zero on success, otherwise (negative) the value of an
 *                error identifier provided by this library.
 */
int libgamma_crtc_restore(libgamma_crtc_state_t* restrict this)
{
$>switch this.partition.site.method return crtc_restore this
}



/**
 * Read information about a CRTC.
 * 
 * @param   this    Instance of a data structure to fill with the information about the CRTC.
 * @param   crtc    The state of the CRTC whose information should be read.
 * @param   fields  OR:ed identifiers for the information about the CRTC that should be read.
 * @return          Zero on success, -1 on error. On error refer to the error reports in `this`.
 */
int libgamma_get_crtc_information(libgamma_crtc_information_t* restrict this,
				  libgamma_crtc_state_t* restrict crtc, int32_t fields)
{
#ifdef HAVE_NO_LIBGAMMA_METHODS
  (void) fields;
#endif
  this->edid = NULL;
  this->connector_name = NULL;
$>switch crtc.partition.site.method return get_crtc_information this crtc fields
}


/**
 * Release all resources in an information data structure for a CRTC.
 * 
 * @param  this  The CRTC information.
 */
void libgamma_crtc_information_destroy(libgamma_crtc_information_t* restrict this)
{
  free(this->edid);
  free(this->connector_name);
}


/**
 * Release all resources in an information data structure for a CRTC
 * and free the data structure pointer.
 * 
 * @param  this  The CRTC information.
 */
void libgamma_crtc_information_free(libgamma_crtc_information_t* restrict this)
{
  libgamma_crtc_information_destroy(this);
  free(this);
}


/**
 * Convert a raw representation of an EDID to a hexadecimal representation.
 * 
 * @param   1       Casing name.
 * @param   2       The hexadecimal alphabet.
 * @param   edid    The EDID in raw representation.
 * @param   length  The length of `edid`.
 * @return          The EDID in hexadecimal representation,
 *                  `NULL` on allocation error, `errno` will be set accordingly.
 */
$>behex_edid ()
$>{
char* libgamma_behex_edid_${1}(const unsigned char* restrict edid, size_t length)
{
  char* restrict out;
  size_t i;
  
  /* Allocate memory area for the output string. */
  if ((out = malloc((length * 2 + 1) * sizeof(char))) == NULL)
    return NULL;
  
  /* Translate from raw octets to hexadecimal. */
  for (i = 0; i < length; i++)
    {
      out[i * 2 + 0] = "${2}"[(edid[i] >> 4) & 15];
      out[i * 2 + 1] = "${2}"[(edid[i] >> 0) & 15];
    }
  /* NUL-terminate the output string. */
  out[length * 2] = '\0';
  
  return out;
}
$>}


/**
 * Convert a raw representation of an EDID to a lowercase hexadecimal representation.
 * 
 * @param   edid    The EDID in raw representation.
 * @param   length  The length of `edid`.
 * @return          The EDID in lowercase hexadecimal representation,
 *                  `NULL` on allocation error, `errno` will be set accordingly.
 */
$>behex_edid lowercase 0123456789abcdef


/**
 * Convert a raw representation of an EDID to an uppercase hexadecimal representation.
 * 
 * @param   edid    The EDID in raw representation.
 * @param   length  The length of `edid`.
 * @return          The EDID in uppercase hexadecimal representation,
 *                  NULL` on allocation error, `errno` will be set accordingly.
 */
$>behex_edid uppercase 0123456789ABCDEF


/**
 * Convert an hexadecimal representation of an EDID to a raw representation.
 * 
 * @param   edid  The EDID in hexadecimal representation.
 * @return        The EDID in raw representation, it will be half the length
 *                of `edid` (the input value). `NULL` on allocation error or
 *                if the EDID is malformated, `errno` will be set accordingly.
 */
unsigned char* libgamma_unhex_edid(const char* restrict edid)
{
#define not_range(lower, V, upper)  ((V < lower) || (upper < V))
#define is_not_hex(V)  (not_range('0', V, '9') && not_range('a', V, 'f') && not_range('A', V, 'F'))
  
  unsigned char* restrict out;
  size_t n = strlen(edid);
  size_t i;
  
  /* Check that the length of the strings is even,
     otherwise it cannot represent bytes. */
  if ((n & 1))
    return errno = EINVAL, NULL;
  
  /* Allocate memory area for output octet array. */
  if ((out = malloc(n /= 2 * sizeof(unsigned char))) == NULL)
    return NULL;
  
  /* Convert to raw octet array. */
  for (i = 0; i < n; i++)
    {
      /* Get the next character pair that, it represents an octet.o */
      char a = edid[i * 2 + 0];
      char b = edid[i * 2 + 1];
      
      /* Verify that the input is in hexadecimal. */
      if (is_not_hex(a) || is_not_hex(b))
	{
	  free(out);
	  return errno = EINVAL, NULL;
	}
      
      /* Convert each chararacter to raw format. */
      a = (char)((a & 15) + (a > '9' ? 9 : 0));
      b = (char)((b & 15) + (b > '9' ? 9 : 0));
      
      /* Combine the two characters into one octet. */
      out[i] = (unsigned char)((a << 4) | b);
    }
  
  return out;
  
#undef is_hex
#undef not_range
}


/**
 * Get the current gamma ramps for a CRTC, 16-bit gamma-depth version.
 * 
 * @param   this   The CRTC state.
 * @param   ramps  The gamma ramps to fill with the current values.
 * @return         Zero on success, otherwise (negative) the value of an
 *                 error identifier provided by this library.
 */
int libgamma_crtc_get_gamma_ramps16(libgamma_crtc_state_t* restrict this,
				    libgamma_gamma_ramps16_t* restrict ramps)
{
#ifdef HAVE_NO_LIBGAMMA_METHODS
  (void) ramps;
#endif
  
  switch (this->partition->site->method)
    {
      /* Methods other than Quartz/CoreGraphics uses 16-bit integers. */
$>for method in $(get-methods | grep -v QUARTZ_CORE_GRAPHICS); do
#ifdef HAVE_LIBGAMMA_METHOD_${method}
    case LIBGAMMA_METHOD_${method}:
      return libgamma_$(lowercase $method)_crtc_get_gamma_ramps16(this, ramps);
#endif
     
     /* The Quartz/CoreGraphics method uses single precision float. */
$>done
#ifdef HAVE_LIBGAMMA_METHOD_QUARTZ_CORE_GRAPHICS
    case LIBGAMMA_METHOD_QUARTZ_CORE_GRAPHICS:
      {
	libgamma_gamma_ramps_any_t ramps_;
	ramps_.bits16 = *ramps;
	return libgamma_translated_ramp_get(this, &ramps_, 16, -1,
					    libgamma_crtc_get_gamma_rampsf);
      }
#endif
      
      /* The selected method does not exist. */
    default:
      return LIBGAMMA_NO_SUCH_ADJUSTMENT_METHOD;
    }
}


/**
 * Set the gamma ramps for a CRTC, 16-bit gamma-depth version.
 * 
 * @param   this   The CRTC state.
 * @param   ramps  The gamma ramps to apply.
 * @return         Zero on success, otherwise (negative) the value of an
 *                 error identifier provided by this library.
 */
int libgamma_crtc_set_gamma_ramps16(libgamma_crtc_state_t* restrict this,
				    libgamma_gamma_ramps16_t ramps)
{
#ifdef HAVE_NO_LIBGAMMA_METHODS
  (void) ramps;
#endif
  
  switch (this->partition->site->method)
    {
      /* Methods other than Quartz/CoreGraphics uses 16-bit integers. */
$>for method in $(get-methods | grep -v QUARTZ_CORE_GRAPHICS); do
#ifdef HAVE_LIBGAMMA_METHOD_${method}
    case LIBGAMMA_METHOD_${method}:
      return libgamma_$(lowercase $method)_crtc_set_gamma_ramps16(this, ramps);
#endif
$>done
     
     /* The Quartz/CoreGraphics method uses single precision float. */
#ifdef HAVE_LIBGAMMA_METHOD_QUARTZ_CORE_GRAPHICS
    case LIBGAMMA_METHOD_QUARTZ_CORE_GRAPHICS:
      {
	libgamma_gamma_ramps_any_t ramps_;
	ramps_.bits16 = ramps;
	return libgamma_translated_ramp_set(this, ramps_, 16, -1,
					    libgamma_crtc_set_gamma_rampsf);
      }
#endif
      
      /* The selected method does not exist. */
    default:
      return LIBGAMMA_NO_SUCH_ADJUSTMENT_METHOD;
    }
}



/**
 * Set or get the gamma ramps for a CRTC, non-16-bit gamma-depth version.
 * 
 * @param   1      Either `get` or `set`, for the action that the name of value implies.
 * @param   2      The `ramp*` pattern for the ramp structure and function to call.
 * @param   3      Either of `bit8`, `bit16`, `bit32`, `bit64`, `float_single`, `float_double`;
 *                 rather self-explanatory.
 * @param   4      The number of bits in the gamma depth, -1 for single precision float,
 *                 (`float`) and -2 for double percition float (`double`).
 * @param   this   The CRTC state.
 * @param   ramps  The gamma ramps to apply, or
 *                 the gamma ramps to fill with the current values.
 * @return         Zero on success, otherwise (negative) the value of an
 *                 error identifier provided by this library.
 */
$>crtc_set_get_gamma_ramps ()
$>{
$<
  action=$1
  ramps=$2
  type=$3
  bits=$4
  p=
  [ $action = get ] && p='*'
$>
int libgamma_crtc_${action}_gamma_${ramps}(libgamma_crtc_state_t* restrict this,
					   libgamma_gamma_${ramps}_t${p:+* restrict} ramps)
{
  libgamma_gamma_ramps_any_t ramps_;
  switch (this->partition->site->method)
    {
      /* The dummy method supports all ramp depths. */
#ifdef HAVE_LIBGAMMA_METHOD_DUMMY
    case LIBGAMMA_METHOD_DUMMY:
      return libgamma_dummy_crtc_${action}_gamma_${ramps}(this, ramps);
#endif
      
      /* The Quartz/CoreGraphics method uses single precision float. */
#ifdef HAVE_LIBGAMMA_METHOD_QUARTZ_CORE_GRAPHICS
    case LIBGAMMA_METHOD_QUARTZ_CORE_GRAPHICS:
$>if [ $bits = -1 ]; then
      /* Single precision float is used. */
      return libgamma_quartz_cg_crtc_${action}_gamma_${ramps}(this, ramps);
$>else
      /* Something else is used and we convert to Single precision float. */
      ramps_.${type} = ${p}ramps;
      return libgamma_translated_ramp_${action}(this, ${p:+&}ramps_, ${bits}, -1,
						libgamma_crtc_${action}_gamma_rampsf);
$>fi
#endif
      
      /* Other methods use 16-bit integers. */
    default:
      ramps_.${type} = ${p}ramps;
      return libgamma_translated_ramp_${action}(this, ${p:+&}ramps_, ${bits}, 16,
						libgamma_crtc_${action}_gamma_ramps16);
    }
}
$>}



/**
 * Get the current gamma ramps for a CRTC, 8-bit gamma-depth version.
 * 
 * @param   this   The CRTC state.
 * @param   ramps  The gamma ramps to fill with the current values.
 * @return         Zero on success, otherwise (negative) the value of an
 *                 error identifier provided by this library.
 */
$>crtc_set_get_gamma_ramps get ramps8 bits8 8


/**
 * Set the gamma ramps for a CRTC, 32-bit gamma-depth version.
 * 
 * @param   this   The CRTC state.
 * @param   ramps  The gamma ramps to apply.
 * @return         Zero on success, otherwise (negative) the value of an
 *                 error identifier provided by this library.
 */
$>crtc_set_get_gamma_ramps set ramps8 bits8 8



/**
 * Get the current gamma ramps for a CRTC, 32-bit gamma-depth version.
 * 
 * @param   this   The CRTC state.
 * @param   ramps  The gamma ramps to fill with the current values.
 * @return         Zero on success, otherwise (negative) the value of an
 *                 error identifier provided by this library.
 */
$>crtc_set_get_gamma_ramps get ramps32 bits32 32


/**
 * Set the gamma ramps for a CRTC, 32-bit gamma-depth version.
 * 
 * @param   this   The CRTC state.
 * @param   ramps  The gamma ramps to apply.
 * @return         Zero on success, otherwise (negative) the value of an
 *                 error identifier provided by this library.
 */
$>crtc_set_get_gamma_ramps set ramps32 bits32 32



/**
 * Get the current gamma ramps for a CRTC, 64-bit gamma-depth version.
 * 
 * @param   this   The CRTC state.
 * @param   ramps  The gamma ramps to fill with the current values.
 * @return         Zero on success, otherwise (negative) the value of an
 *                 error identifier provided by this library.
 */
$>crtc_set_get_gamma_ramps get ramps64 bits64 64


/**
 * Set the gamma ramps for a CRTC, 64-bit gamma-depth version.
 * 
 * @param   this   The CRTC state.
 * @param   ramps  The gamma ramps to apply.
 * @return         Zero on success, otherwise (negative) the value of an
 *                 error identifier provided by this library.
 */
$>crtc_set_get_gamma_ramps set ramps64 bits64 64


/**
 * Get the current gamma ramps for a CRTC, `float` version.
 * 
 * @param   this   The CRTC state.
 * @param   ramps  The gamma ramps to fill with the current values.
 * @return         Zero on success, otherwise (negative) the value of an
 *                 error identifier provided by this library.
 */
$>crtc_set_get_gamma_ramps get rampsf float_single -1


/**
 * Set the gamma ramps for a CRTC, `float` version.
 * 
 * @param   this   The CRTC state.
 * @param   ramps  The gamma ramps to apply.
 * @return         Zero on success, otherwise (negative) the value of an
 *                 error identifier provided by this library.
 */
$>crtc_set_get_gamma_ramps set rampsf float_single -1



/**
 * Get the current gamma ramps for a CRTC, `double` version.
 * 
 * @param   this   The CRTC state.
 * @param   ramps  The gamma ramps to fill with the current values.
 * @return         Zero on success, otherwise (negative) the value of an
 *                 error identifier provided by this library.
 */
$>crtc_set_get_gamma_ramps get rampsd float_double -2


/**
 * Set the gamma ramps for a CRTC, `double` version.
 * 
 * @param   this   The CRTC state.
 * @param   ramps  The gamma ramps to apply.
 * @return         Zero on success, otherwise (negative) the value of an
 *                 error identifier provided by this library.
 */
$>crtc_set_get_gamma_ramps set rampsd float_double -2



/**
 * Set the gamma ramps for a CRTC.
 * 
 * Note that this will probably involve the library allocating temporary data.
 * 
 * @param   1               The data type for the ramp stop elements.
 * @param   2               The `ramp*` pattern for the ramp structure and function to call.
 * @param   this            The CRTC state.
 * @param   red_function    The function that generates the gamma ramp for the red channel.
 * @param   green_function  The function that generates the gamma ramp for the green channel.
 * @param   blue_function   The function that generates the gamma ramp for the blue channel.
 * @return                  Zero on success, otherwise (negative) the value of an
 *                          error identifier provided by this library.
 */
$>crtc_set_gamma_ramps_f ()
$>{
int libgamma_crtc_set_gamma_${2}_f(libgamma_crtc_state_t* restrict this,
				   libgamma_gamma_${2}_fun* red_function,
				   libgamma_gamma_${2}_fun* green_function,
				   libgamma_gamma_${2}_fun* blue_function)
{
  libgamma_crtc_information_t info;
  libgamma_gamma_${2}_t ramps;
  size_t i, n;
  int e;
  
  /* Get the size of the gamma ramps. */
  if (libgamma_get_crtc_information(&info, this, LIBGAMMA_CRTC_INFO_GAMMA_SIZE))
    {
      if ((e = info.gamma_size_error) < 0)
	return e;
      return errno = e, LIBGAMMA_ERRNO_SET;
    }
  
  /* Copy the size of the gamma ramps and calculte the grand size. */
  n  = ramps.  red_size = info.  red_gamma_size;
  n += ramps.green_size = info.green_gamma_size;
  n += ramps. blue_size = info. blue_gamma_size;
  
  /* Allocate gamma ramps. */
  ramps.  red = malloc(n * sizeof(${1}));
  ramps.green = ramps.  red + ramps.  red_size;
  ramps. blue = ramps.green + ramps.green_size;
  if (ramps.red == NULL)
    return LIBGAMMA_ERRNO_SET;
  
  /* Generate the gamma ramp for the red chennel. */
  for (i = 0, n = ramps.red_size; i < n; i++)
    ramps.red[i] = red_function((float)i / (float)(n - 1));
  
  /* Generate the gamma ramp for the green chennel. */
  for (i = 0, n = ramps.green_size; i < n; i++)
    ramps.green[i] = green_function((float)i / (float)(n - 1));
  
  /* Generate the gamma ramp for the blue chennel. */
  for (i = 0, n = ramps.blue_size; i < n; i++)
    ramps.blue[i] = blue_function((float)i / (float)(n - 1));
  
  /* Apply the gamma ramps. */
  e = libgamma_crtc_set_gamma_${2}(this, ramps);
  free(ramps.red);
  return e;
}
$>}


/**
 * Set the gamma ramps for a CRTC, 8-bit gamma-depth function version.
 * 
 * Note that this will probably involve the library allocating temporary data.
 * 
 * @param   this            The CRTC state.
 * @param   red_function    The function that generates the gamma ramp for the red channel.
 * @param   green_function  The function that generates the gamma ramp for the green channel.
 * @param   blue_function   The function that generates the gamma ramp for the blue channel.
 * @return                  Zero on success, otherwise (negative) the value of an
 *                          error identifier provided by this library.
 */
$>crtc_set_gamma_ramps_f uint8_t ramps8


/**
 * Set the gamma ramps for a CRTC, 16-bit gamma-depth function version.
 * 
 * Note that this will probably involve the library allocating temporary data.
 * 
 * @param   this            The CRTC state.
 * @param   red_function    The function that generates the gamma ramp for the red channel.
 * @param   green_function  The function that generates the gamma ramp for the green channel.
 * @param   blue_function   The function that generates the gamma ramp for the blue channel.
 * @return                  Zero on success, otherwise (negative) the value of an
 *                          error identifier provided by this library.
 */
$>crtc_set_gamma_ramps_f uint16_t ramps16


/**
 * Set the gamma ramps for a CRTC, 32-bit gamma-depth function version.
 * 
 * Note that this will probably involve the library allocating temporary data.
 * 
 * @param   this            The CRTC state.
 * @param   red_function    The function that generates the gamma ramp for the red channel.
 * @param   green_function  The function that generates the gamma ramp for the green channel.
 * @param   blue_function   The function that generates the gamma ramp for the blue channel.
 * @return                  Zero on success, otherwise (negative) the value of an
 *                          error identifier provided by this library.
 */
$>crtc_set_gamma_ramps_f uint32_t ramps32


/**
 * Set the gamma ramps for a CRTC, 64-bit gamma-depth function version.
 * 
 * Note that this will probably involve the library allocating temporary data.
 * 
 * @param   this            The CRTC state.
 * @param   red_function    The function that generates the gamma ramp for the red channel.
 * @param   green_function  The function that generates the gamma ramp for the green channel.
 * @param   blue_function   The function that generates the gamma ramp for the blue channel.
 * @return                  Zero on success, otherwise (negative) the value of an
 *                          error identifier provided by this library.
 */
$>crtc_set_gamma_ramps_f uint64_t ramps64


/**
 * Set the gamma ramps for a CRTC, `float` function version.
 * 
 * Note that this will probably involve the library allocating temporary data.
 * 
 * @param   this            The CRTC state.
 * @param   red_function    The function that generates the gamma ramp for the red channel.
 * @param   green_function  The function that generates the gamma ramp for the green channel.
 * @param   blue_function   The function that generates the gamma ramp for the blue channel.
 * @return                  Zero on success, otherwise (negative) the value of an
 *                          error identifier provided by this library.
 */
$>crtc_set_gamma_ramps_f float rampsf


/**
 * Set the gamma ramps for a CRTC, `double` function version.
 * 
 * Note that this will probably involve the library allocating temporary data.
 * 
 * @param   this            The CRTC state.
 * @param   red_function    The function that generates the gamma ramp for the red channel.
 * @param   green_function  The function that generates the gamma ramp for the green channel.
 * @param   blue_function   The function that generates the gamma ramp for the blue channel.
 * @return                  Zero on success, otherwise (negative) the value of an
 *                          error identifier provided by this library.
 */
$>crtc_set_gamma_ramps_f double rampsd



#ifdef HAVE_NO_LIBGAMMA_METHODS
# ifdef __GCC__
#  pragma GCC diagnostic pop
# endif
#endif