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media/libvpx/vp9/common/vp9_scan.c@b8a032363ba2 (annotated)

media/libvpx/vp9/common/vp9_scan.c

Thu, 22 Jan 2015 13:21:57 +0100

author

Michael Schloh von Bennewitz <michael@schloh.com>

date

Thu, 22 Jan 2015 13:21:57 +0100

branch

TOR_BUG_9701

changeset 15

b8a032363ba2

permissions

-rw-r--r--

Incorporate requested changes from Mozilla in review:
https://bugzilla.mozilla.org/show_bug.cgi?id=1123480#c6

michael@0	1	/*
michael@0	2	* Copyright (c) 2010 The WebM project authors. All Rights Reserved.
michael@0	3	*
michael@0	4	* Use of this source code is governed by a BSD-style license
michael@0	5	* that can be found in the LICENSE file in the root of the source
michael@0	6	* tree. An additional intellectual property rights grant can be found
michael@0	7	* in the file PATENTS. All contributing project authors may
michael@0	8	* be found in the AUTHORS file in the root of the source tree.
michael@0	9	*/
michael@0	10
michael@0	11	#include <assert.h>
michael@0	12
michael@0	13	#include "vp9/common/vp9_scan.h"
michael@0	14
michael@0	15	DECLARE_ALIGNED(16, const int16_t, vp9_default_scan_4x4[16]) = {
michael@0	16	0, 4, 1, 5,
michael@0	17	8, 2, 12, 9,
michael@0	18	3, 6, 13, 10,
michael@0	19	7, 14, 11, 15,
michael@0	20	};
michael@0	21
michael@0	22	DECLARE_ALIGNED(16, const int16_t, vp9_col_scan_4x4[16]) = {
michael@0	23	0, 4, 8, 1,
michael@0	24	12, 5, 9, 2,
michael@0	25	13, 6, 10, 3,
michael@0	26	7, 14, 11, 15,
michael@0	27	};
michael@0	28
michael@0	29	DECLARE_ALIGNED(16, const int16_t, vp9_row_scan_4x4[16]) = {
michael@0	30	0, 1, 4, 2,
michael@0	31	5, 3, 6, 8,
michael@0	32	9, 7, 12, 10,
michael@0	33	13, 11, 14, 15,
michael@0	34	};
michael@0	35
michael@0	36	DECLARE_ALIGNED(16, const int16_t, vp9_default_scan_8x8[64]) = {
michael@0	37	0, 8, 1, 16, 9, 2, 17, 24,
michael@0	38	10, 3, 18, 25, 32, 11, 4, 26,
michael@0	39	33, 19, 40, 12, 34, 27, 5, 41,
michael@0	40	20, 48, 13, 35, 42, 28, 21, 6,
michael@0	41	49, 56, 36, 43, 29, 7, 14, 50,
michael@0	42	57, 44, 22, 37, 15, 51, 58, 30,
michael@0	43	45, 23, 52, 59, 38, 31, 60, 53,
michael@0	44	46, 39, 61, 54, 47, 62, 55, 63,
michael@0	45	};
michael@0	46
michael@0	47	DECLARE_ALIGNED(16, const int16_t, vp9_col_scan_8x8[64]) = {
michael@0	48	0, 8, 16, 1, 24, 9, 32, 17,
michael@0	49	2, 40, 25, 10, 33, 18, 48, 3,
michael@0	50	26, 41, 11, 56, 19, 34, 4, 49,
michael@0	51	27, 42, 12, 35, 20, 57, 50, 28,
michael@0	52	5, 43, 13, 36, 58, 51, 21, 44,
michael@0	53	6, 29, 59, 37, 14, 52, 22, 7,
michael@0	54	45, 60, 30, 15, 38, 53, 23, 46,
michael@0	55	31, 61, 39, 54, 47, 62, 55, 63,
michael@0	56	};
michael@0	57
michael@0	58	DECLARE_ALIGNED(16, const int16_t, vp9_row_scan_8x8[64]) = {
michael@0	59	0, 1, 2, 8, 9, 3, 16, 10,
michael@0	60	4, 17, 11, 24, 5, 18, 25, 12,
michael@0	61	19, 26, 32, 6, 13, 20, 33, 27,
michael@0	62	7, 34, 40, 21, 28, 41, 14, 35,
michael@0	63	48, 42, 29, 36, 49, 22, 43, 15,
michael@0	64	56, 37, 50, 44, 30, 57, 23, 51,
michael@0	65	58, 45, 38, 52, 31, 59, 53, 46,
michael@0	66	60, 39, 61, 47, 54, 55, 62, 63,
michael@0	67	};
michael@0	68
michael@0	69	DECLARE_ALIGNED(16, const int16_t, vp9_default_scan_16x16[256]) = {
michael@0	70	0, 16, 1, 32, 17, 2, 48, 33, 18, 3, 64, 34, 49, 19, 65, 80,
michael@0	71	50, 4, 35, 66, 20, 81, 96, 51, 5, 36, 82, 97, 67, 112, 21, 52,
michael@0	72	98, 37, 83, 113, 6, 68, 128, 53, 22, 99, 114, 84, 7, 129, 38, 69,
michael@0	73	100, 115, 144, 130, 85, 54, 23, 8, 145, 39, 70, 116, 101, 131, 160, 146,
michael@0	74	55, 86, 24, 71, 132, 117, 161, 40, 9, 102, 147, 176, 162, 87, 56, 25,
michael@0	75	133, 118, 177, 148, 72, 103, 41, 163, 10, 192, 178, 88, 57, 134, 149, 119,
michael@0	76	26, 164, 73, 104, 193, 42, 179, 208, 11, 135, 89, 165, 120, 150, 58, 194,
michael@0	77	180, 27, 74, 209, 105, 151, 136, 43, 90, 224, 166, 195, 181, 121, 210, 59,
michael@0	78	12, 152, 106, 167, 196, 75, 137, 225, 211, 240, 182, 122, 91, 28, 197, 13,
michael@0	79	226, 168, 183, 153, 44, 212, 138, 107, 241, 60, 29, 123, 198, 184, 227, 169,
michael@0	80	242, 76, 213, 154, 45, 92, 14, 199, 139, 61, 228, 214, 170, 185, 243, 108,
michael@0	81	77, 155, 30, 15, 200, 229, 124, 215, 244, 93, 46, 186, 171, 201, 109, 140,
michael@0	82	230, 62, 216, 245, 31, 125, 78, 156, 231, 47, 187, 202, 217, 94, 246, 141,
michael@0	83	63, 232, 172, 110, 247, 157, 79, 218, 203, 126, 233, 188, 248, 95, 173, 142,
michael@0	84	219, 111, 249, 234, 158, 127, 189, 204, 250, 235, 143, 174, 220, 205, 159,
michael@0	85	251,
michael@0	86	190, 221, 175, 236, 237, 191, 206, 252, 222, 253, 207, 238, 223, 254, 239,
michael@0	87	255,
michael@0	88	};
michael@0	89
michael@0	90	DECLARE_ALIGNED(16, const int16_t, vp9_col_scan_16x16[256]) = {
michael@0	91	0, 16, 32, 48, 1, 64, 17, 80, 33, 96, 49, 2, 65, 112, 18, 81,
michael@0	92	34, 128, 50, 97, 3, 66, 144, 19, 113, 35, 82, 160, 98, 51, 129, 4,
michael@0	93	67, 176, 20, 114, 145, 83, 36, 99, 130, 52, 192, 5, 161, 68, 115, 21,
michael@0	94	146, 84, 208, 177, 37, 131, 100, 53, 162, 224, 69, 6, 116, 193, 147, 85,
michael@0	95	22, 240, 132, 38, 178, 101, 163, 54, 209, 117, 70, 7, 148, 194, 86, 179,
michael@0	96	225, 23, 133, 39, 164, 8, 102, 210, 241, 55, 195, 118, 149, 71, 180, 24,
michael@0	97	87, 226, 134, 165, 211, 40, 103, 56, 72, 150, 196, 242, 119, 9, 181, 227,
michael@0	98	88, 166, 25, 135, 41, 104, 212, 57, 151, 197, 120, 73, 243, 182, 136, 167,
michael@0	99	213, 89, 10, 228, 105, 152, 198, 26, 42, 121, 183, 244, 168, 58, 137, 229,
michael@0	100	74, 214, 90, 153, 199, 184, 11, 106, 245, 27, 122, 230, 169, 43, 215, 59,
michael@0	101	200, 138, 185, 246, 75, 12, 91, 154, 216, 231, 107, 28, 44, 201, 123, 170,
michael@0	102	60, 247, 232, 76, 139, 13, 92, 217, 186, 248, 155, 108, 29, 124, 45, 202,
michael@0	103	233, 171, 61, 14, 77, 140, 15, 249, 93, 30, 187, 156, 218, 46, 109, 125,
michael@0	104	62, 172, 78, 203, 31, 141, 234, 94, 47, 188, 63, 157, 110, 250, 219, 79,
michael@0	105	126, 204, 173, 142, 95, 189, 111, 235, 158, 220, 251, 127, 174, 143, 205,
michael@0	106	236,
michael@0	107	159, 190, 221, 252, 175, 206, 237, 191, 253, 222, 238, 207, 254, 223, 239,
michael@0	108	255,
michael@0	109	};
michael@0	110
michael@0	111	DECLARE_ALIGNED(16, const int16_t, vp9_row_scan_16x16[256]) = {
michael@0	112	0, 1, 2, 16, 3, 17, 4, 18, 32, 5, 33, 19, 6, 34, 48, 20,
michael@0	113	49, 7, 35, 21, 50, 64, 8, 36, 65, 22, 51, 37, 80, 9, 66, 52,
michael@0	114	23, 38, 81, 67, 10, 53, 24, 82, 68, 96, 39, 11, 54, 83, 97, 69,
michael@0	115	25, 98, 84, 40, 112, 55, 12, 70, 99, 113, 85, 26, 41, 56, 114, 100,
michael@0	116	13, 71, 128, 86, 27, 115, 101, 129, 42, 57, 72, 116, 14, 87, 130, 102,
michael@0	117	144, 73, 131, 117, 28, 58, 15, 88, 43, 145, 103, 132, 146, 118, 74, 160,
michael@0	118	89, 133, 104, 29, 59, 147, 119, 44, 161, 148, 90, 105, 134, 162, 120, 176,
michael@0	119	75, 135, 149, 30, 60, 163, 177, 45, 121, 91, 106, 164, 178, 150, 192, 136,
michael@0	120	165, 179, 31, 151, 193, 76, 122, 61, 137, 194, 107, 152, 180, 208, 46, 166,
michael@0	121	167, 195, 92, 181, 138, 209, 123, 153, 224, 196, 77, 168, 210, 182, 240, 108,
michael@0	122	197, 62, 154, 225, 183, 169, 211, 47, 139, 93, 184, 226, 212, 241, 198, 170,
michael@0	123	124, 155, 199, 78, 213, 185, 109, 227, 200, 63, 228, 242, 140, 214, 171, 186,
michael@0	124	156, 229, 243, 125, 94, 201, 244, 215, 216, 230, 141, 187, 202, 79, 172, 110,
michael@0	125	157, 245, 217, 231, 95, 246, 232, 126, 203, 247, 233, 173, 218, 142, 111,
michael@0	126	158,
michael@0	127	188, 248, 127, 234, 219, 249, 189, 204, 143, 174, 159, 250, 235, 205, 220,
michael@0	128	175,
michael@0	129	190, 251, 221, 191, 206, 236, 207, 237, 252, 222, 253, 223, 238, 239, 254,
michael@0	130	255,
michael@0	131	};
michael@0	132
michael@0	133	DECLARE_ALIGNED(16, const int16_t, vp9_default_scan_32x32[1024]) = {
michael@0	134	0, 32, 1, 64, 33, 2, 96, 65, 34, 128, 3, 97, 66, 160,
michael@0	135	129, 35, 98, 4, 67, 130, 161, 192, 36, 99, 224, 5, 162, 193,
michael@0	136	68, 131, 37, 100,
michael@0	137	225, 194, 256, 163, 69, 132, 6, 226, 257, 288, 195, 101, 164, 38,
michael@0	138	258, 7, 227, 289, 133, 320, 70, 196, 165, 290, 259, 228, 39, 321,
michael@0	139	102, 352, 8, 197,
michael@0	140	71, 134, 322, 291, 260, 353, 384, 229, 166, 103, 40, 354, 323, 292,
michael@0	141	135, 385, 198, 261, 72, 9, 416, 167, 386, 355, 230, 324, 104, 293,
michael@0	142	41, 417, 199, 136,
michael@0	143	262, 387, 448, 325, 356, 10, 73, 418, 231, 168, 449, 294, 388, 105,
michael@0	144	419, 263, 42, 200, 357, 450, 137, 480, 74, 326, 232, 11, 389, 169,
michael@0	145	295, 420, 106, 451,
michael@0	146	481, 358, 264, 327, 201, 43, 138, 512, 482, 390, 296, 233, 170, 421,
michael@0	147	75, 452, 359, 12, 513, 265, 483, 328, 107, 202, 514, 544, 422, 391,
michael@0	148	453, 139, 44, 234,
michael@0	149	484, 297, 360, 171, 76, 515, 545, 266, 329, 454, 13, 423, 203, 108,
michael@0	150	546, 485, 576, 298, 235, 140, 361, 330, 172, 547, 45, 455, 267, 577,
michael@0	151	486, 77, 204, 362,
michael@0	152	608, 14, 299, 578, 109, 236, 487, 609, 331, 141, 579, 46, 15, 173,
michael@0	153	610, 363, 78, 205, 16, 110, 237, 611, 142, 47, 174, 79, 206, 17,
michael@0	154	111, 238, 48, 143,
michael@0	155	80, 175, 112, 207, 49, 18, 239, 81, 113, 19, 50, 82, 114, 51,
michael@0	156	83, 115, 640, 516, 392, 268, 144, 20, 672, 641, 548, 517, 424,
michael@0	157	393, 300, 269, 176, 145,
michael@0	158	52, 21, 704, 673, 642, 580, 549, 518, 456, 425, 394, 332, 301,
michael@0	159	270, 208, 177, 146, 84, 53, 22, 736, 705, 674, 643, 612, 581,
michael@0	160	550, 519, 488, 457, 426, 395,
michael@0	161	364, 333, 302, 271, 240, 209, 178, 147, 116, 85, 54, 23, 737,
michael@0	162	706, 675, 613, 582, 551, 489, 458, 427, 365, 334, 303, 241,
michael@0	163	210, 179, 117, 86, 55, 738, 707,
michael@0	164	614, 583, 490, 459, 366, 335, 242, 211, 118, 87, 739, 615, 491,
michael@0	165	367, 243, 119, 768, 644, 520, 396, 272, 148, 24, 800, 769, 676,
michael@0	166	645, 552, 521, 428, 397, 304,
michael@0	167	273, 180, 149, 56, 25, 832, 801, 770, 708, 677, 646, 584, 553,
michael@0	168	522, 460, 429, 398, 336, 305, 274, 212, 181, 150, 88, 57, 26,
michael@0	169	864, 833, 802, 771, 740, 709,
michael@0	170	678, 647, 616, 585, 554, 523, 492, 461, 430, 399, 368, 337, 306,
michael@0	171	275, 244, 213, 182, 151, 120, 89, 58, 27, 865, 834, 803, 741,
michael@0	172	710, 679, 617, 586, 555, 493,
michael@0	173	462, 431, 369, 338, 307, 245, 214, 183, 121, 90, 59, 866, 835,
michael@0	174	742, 711, 618, 587, 494, 463, 370, 339, 246, 215, 122, 91, 867,
michael@0	175	743, 619, 495, 371, 247, 123,
michael@0	176	896, 772, 648, 524, 400, 276, 152, 28, 928, 897, 804, 773, 680,
michael@0	177	649, 556, 525, 432, 401, 308, 277, 184, 153, 60, 29, 960, 929,
michael@0	178	898, 836, 805, 774, 712, 681,
michael@0	179	650, 588, 557, 526, 464, 433, 402, 340, 309, 278, 216, 185, 154,
michael@0	180	92, 61, 30, 992, 961, 930, 899, 868, 837, 806, 775, 744, 713, 682,
michael@0	181	651, 620, 589, 558, 527,
michael@0	182	496, 465, 434, 403, 372, 341, 310, 279, 248, 217, 186, 155, 124,
michael@0	183	93, 62, 31, 993, 962, 931, 869, 838, 807, 745, 714, 683, 621, 590,
michael@0	184	559, 497, 466, 435, 373,
michael@0	185	342, 311, 249, 218, 187, 125, 94, 63, 994, 963, 870, 839, 746, 715,
michael@0	186	622, 591, 498, 467, 374, 343, 250, 219, 126, 95, 995, 871, 747, 623,
michael@0	187	499, 375, 251, 127,
michael@0	188	900, 776, 652, 528, 404, 280, 156, 932, 901, 808, 777, 684, 653, 560,
michael@0	189	529, 436, 405, 312, 281, 188, 157, 964, 933, 902, 840, 809, 778, 716,
michael@0	190	685, 654, 592, 561,
michael@0	191	530, 468, 437, 406, 344, 313, 282, 220, 189, 158, 996, 965, 934, 903,
michael@0	192	872, 841, 810, 779, 748, 717, 686, 655, 624, 593, 562, 531, 500, 469,
michael@0	193	438, 407, 376, 345,
michael@0	194	314, 283, 252, 221, 190, 159, 997, 966, 935, 873, 842, 811, 749, 718,
michael@0	195	687, 625, 594, 563, 501, 470, 439, 377, 346, 315, 253, 222, 191, 998,
michael@0	196	967, 874, 843, 750,
michael@0	197	719, 626, 595, 502, 471, 378, 347, 254, 223, 999, 875, 751, 627, 503,
michael@0	198	379, 255, 904, 780, 656, 532, 408, 284, 936, 905, 812, 781, 688, 657,
michael@0	199	564, 533, 440, 409,
michael@0	200	316, 285, 968, 937, 906, 844, 813, 782, 720, 689, 658, 596, 565, 534,
michael@0	201	472, 441, 410, 348, 317, 286, 1000, 969, 938, 907, 876, 845, 814, 783,
michael@0	202	752, 721, 690, 659,
michael@0	203	628, 597, 566, 535, 504, 473, 442, 411, 380, 349, 318, 287, 1001, 970,
michael@0	204	939, 877, 846, 815, 753, 722, 691, 629, 598, 567, 505, 474, 443, 381,
michael@0	205	350, 319, 1002, 971,
michael@0	206	878, 847, 754, 723, 630, 599, 506, 475, 382, 351, 1003, 879, 755, 631,
michael@0	207	507, 383, 908, 784, 660, 536, 412, 940, 909, 816, 785, 692, 661, 568,
michael@0	208	537, 444, 413, 972,
michael@0	209	941, 910, 848, 817, 786, 724, 693, 662, 600, 569, 538, 476, 445, 414,
michael@0	210	1004, 973, 942, 911, 880, 849, 818, 787, 756, 725, 694, 663, 632, 601,
michael@0	211	570, 539, 508, 477,
michael@0	212	446, 415, 1005, 974, 943, 881, 850, 819, 757, 726, 695, 633, 602, 571,
michael@0	213	509, 478, 447, 1006, 975, 882, 851, 758, 727, 634, 603, 510, 479,
michael@0	214	1007, 883, 759, 635, 511,
michael@0	215	912, 788, 664, 540, 944, 913, 820, 789, 696, 665, 572, 541, 976, 945,
michael@0	216	914, 852, 821, 790, 728, 697, 666, 604, 573, 542, 1008, 977, 946, 915,
michael@0	217	884, 853, 822, 791,
michael@0	218	760, 729, 698, 667, 636, 605, 574, 543, 1009, 978, 947, 885, 854, 823,
michael@0	219	761, 730, 699, 637, 606, 575, 1010, 979, 886, 855, 762, 731, 638, 607,
michael@0	220	1011, 887, 763, 639,
michael@0	221	916, 792, 668, 948, 917, 824, 793, 700, 669, 980, 949, 918, 856, 825,
michael@0	222	794, 732, 701, 670, 1012, 981, 950, 919, 888, 857, 826, 795, 764, 733,
michael@0	223	702, 671, 1013, 982,
michael@0	224	951, 889, 858, 827, 765, 734, 703, 1014, 983, 890, 859, 766, 735, 1015,
michael@0	225	891, 767, 920, 796, 952, 921, 828, 797, 984, 953, 922, 860, 829, 798,
michael@0	226	1016, 985, 954, 923,
michael@0	227	892, 861, 830, 799, 1017, 986, 955, 893, 862, 831, 1018, 987, 894, 863,
michael@0	228	1019, 895, 924, 956, 925, 988, 957, 926, 1020, 989, 958, 927, 1021,
michael@0	229	990, 959, 1022, 991, 1023,
michael@0	230	};
michael@0	231
michael@0	232	// Neighborhood 5-tuples for various scans and blocksizes,
michael@0	233	// in {top, left, topleft, topright, bottomleft} order
michael@0	234	// for each position in raster scan order.
michael@0	235	// -1 indicates the neighbor does not exist.
michael@0	236	DECLARE_ALIGNED(16, int16_t,
michael@0	237	vp9_default_scan_4x4_neighbors[17 * MAX_NEIGHBORS]);
michael@0	238	DECLARE_ALIGNED(16, int16_t,
michael@0	239	vp9_col_scan_4x4_neighbors[17 * MAX_NEIGHBORS]);
michael@0	240	DECLARE_ALIGNED(16, int16_t,
michael@0	241	vp9_row_scan_4x4_neighbors[17 * MAX_NEIGHBORS]);
michael@0	242	DECLARE_ALIGNED(16, int16_t,
michael@0	243	vp9_col_scan_8x8_neighbors[65 * MAX_NEIGHBORS]);
michael@0	244	DECLARE_ALIGNED(16, int16_t,
michael@0	245	vp9_row_scan_8x8_neighbors[65 * MAX_NEIGHBORS]);
michael@0	246	DECLARE_ALIGNED(16, int16_t,
michael@0	247	vp9_default_scan_8x8_neighbors[65 * MAX_NEIGHBORS]);
michael@0	248	DECLARE_ALIGNED(16, int16_t,
michael@0	249	vp9_col_scan_16x16_neighbors[257 * MAX_NEIGHBORS]);
michael@0	250	DECLARE_ALIGNED(16, int16_t,
michael@0	251	vp9_row_scan_16x16_neighbors[257 * MAX_NEIGHBORS]);
michael@0	252	DECLARE_ALIGNED(16, int16_t,
michael@0	253	vp9_default_scan_16x16_neighbors[257 * MAX_NEIGHBORS]);
michael@0	254	DECLARE_ALIGNED(16, int16_t,
michael@0	255	vp9_default_scan_32x32_neighbors[1025 * MAX_NEIGHBORS]);
michael@0	256
michael@0	257
michael@0	258	DECLARE_ALIGNED(16, int16_t, vp9_default_iscan_4x4[16]);
michael@0	259	DECLARE_ALIGNED(16, int16_t, vp9_col_iscan_4x4[16]);
michael@0	260	DECLARE_ALIGNED(16, int16_t, vp9_row_iscan_4x4[16]);
michael@0	261	DECLARE_ALIGNED(16, int16_t, vp9_col_iscan_8x8[64]);
michael@0	262	DECLARE_ALIGNED(16, int16_t, vp9_row_iscan_8x8[64]);
michael@0	263	DECLARE_ALIGNED(16, int16_t, vp9_default_iscan_8x8[64]);
michael@0	264	DECLARE_ALIGNED(16, int16_t, vp9_col_iscan_16x16[256]);
michael@0	265	DECLARE_ALIGNED(16, int16_t, vp9_row_iscan_16x16[256]);
michael@0	266	DECLARE_ALIGNED(16, int16_t, vp9_default_iscan_16x16[256]);
michael@0	267	DECLARE_ALIGNED(16, int16_t, vp9_default_iscan_32x32[1024]);
michael@0	268
michael@0	269	static int find_in_scan(const int16_t *scan, int l, int idx) {
michael@0	270	int n, l2 = l * l;
michael@0	271	for (n = 0; n < l2; n++) {
michael@0	272	int rc = scan[n];
michael@0	273	if (rc == idx)
michael@0	274	return n;
michael@0	275	}
michael@0	276	assert(0);
michael@0	277	return -1;
michael@0	278	}
michael@0	279	static void init_scan_neighbors(const int16_t *scan,
michael@0	280	int16_t *iscan,
michael@0	281	int l, int16_t *neighbors) {
michael@0	282	int l2 = l * l;
michael@0	283	int n, i, j;
michael@0	284
michael@0	285	// dc doesn't use this type of prediction
michael@0	286	neighbors[MAX_NEIGHBORS * 0 + 0] = 0;
michael@0	287	neighbors[MAX_NEIGHBORS * 0 + 1] = 0;
michael@0	288	iscan[0] = find_in_scan(scan, l, 0);
michael@0	289	for (n = 1; n < l2; n++) {
michael@0	290	int rc = scan[n];
michael@0	291	iscan[n] = find_in_scan(scan, l, n);
michael@0	292	i = rc / l;
michael@0	293	j = rc % l;
michael@0	294	if (i > 0 && j > 0) {
michael@0	295	// col/row scan is used for adst/dct, and generally means that
michael@0	296	// energy decreases to zero much faster in the dimension in
michael@0	297	// which ADST is used compared to the direction in which DCT
michael@0	298	// is used. Likewise, we find much higher correlation between
michael@0	299	// coefficients within the direction in which DCT is used.
michael@0	300	// Therefore, if we use ADST/DCT, prefer the DCT neighbor coeff
michael@0	301	// as a context. If ADST or DCT is used in both directions, we
michael@0	302	// use the combination of the two as a context.
michael@0	303	int a = (i - 1) * l + j;
michael@0	304	int b = i * l + j - 1;
michael@0	305	if (scan == vp9_col_scan_4x4 || scan == vp9_col_scan_8x8 ||
michael@0	306	scan == vp9_col_scan_16x16) {
michael@0	307	// in the col/row scan cases (as well as left/top edge cases), we set
michael@0	308	// both contexts to the same value, so we can branchlessly do a+b+1>>1
michael@0	309	// which automatically becomes a if a == b
michael@0	310	neighbors[MAX_NEIGHBORS * n + 0] =
michael@0	311	neighbors[MAX_NEIGHBORS * n + 1] = a;
michael@0	312	} else if (scan == vp9_row_scan_4x4 || scan == vp9_row_scan_8x8 ||
michael@0	313	scan == vp9_row_scan_16x16) {
michael@0	314	neighbors[MAX_NEIGHBORS * n + 0] =
michael@0	315	neighbors[MAX_NEIGHBORS * n + 1] = b;
michael@0	316	} else {
michael@0	317	neighbors[MAX_NEIGHBORS * n + 0] = a;
michael@0	318	neighbors[MAX_NEIGHBORS * n + 1] = b;
michael@0	319	}
michael@0	320	} else if (i > 0) {
michael@0	321	neighbors[MAX_NEIGHBORS * n + 0] =
michael@0	322	neighbors[MAX_NEIGHBORS * n + 1] = (i - 1) * l + j;
michael@0	323	} else {
michael@0	324	assert(j > 0);
michael@0	325	neighbors[MAX_NEIGHBORS * n + 0] =
michael@0	326	neighbors[MAX_NEIGHBORS * n + 1] = i * l + j - 1;
michael@0	327	}
michael@0	328	assert(iscan[neighbors[MAX_NEIGHBORS * n + 0]] < n);
michael@0	329	}
michael@0	330	// one padding item so we don't have to add branches in code to handle
michael@0	331	// calls to get_coef_context() for the token after the final dc token
michael@0	332	neighbors[MAX_NEIGHBORS * l2 + 0] = 0;
michael@0	333	neighbors[MAX_NEIGHBORS * l2 + 1] = 0;
michael@0	334	}
michael@0	335
michael@0	336	void vp9_init_neighbors() {
michael@0	337	init_scan_neighbors(vp9_default_scan_4x4, vp9_default_iscan_4x4, 4,
michael@0	338	vp9_default_scan_4x4_neighbors);
michael@0	339	init_scan_neighbors(vp9_row_scan_4x4, vp9_row_iscan_4x4, 4,
michael@0	340	vp9_row_scan_4x4_neighbors);
michael@0	341	init_scan_neighbors(vp9_col_scan_4x4, vp9_col_iscan_4x4, 4,
michael@0	342	vp9_col_scan_4x4_neighbors);
michael@0	343	init_scan_neighbors(vp9_default_scan_8x8, vp9_default_iscan_8x8, 8,
michael@0	344	vp9_default_scan_8x8_neighbors);
michael@0	345	init_scan_neighbors(vp9_row_scan_8x8, vp9_row_iscan_8x8, 8,
michael@0	346	vp9_row_scan_8x8_neighbors);
michael@0	347	init_scan_neighbors(vp9_col_scan_8x8, vp9_col_iscan_8x8, 8,
michael@0	348	vp9_col_scan_8x8_neighbors);
michael@0	349	init_scan_neighbors(vp9_default_scan_16x16, vp9_default_iscan_16x16, 16,
michael@0	350	vp9_default_scan_16x16_neighbors);
michael@0	351	init_scan_neighbors(vp9_row_scan_16x16, vp9_row_iscan_16x16, 16,
michael@0	352	vp9_row_scan_16x16_neighbors);
michael@0	353	init_scan_neighbors(vp9_col_scan_16x16, vp9_col_iscan_16x16, 16,
michael@0	354	vp9_col_scan_16x16_neighbors);
michael@0	355	init_scan_neighbors(vp9_default_scan_32x32, vp9_default_iscan_32x32, 32,
michael@0	356	vp9_default_scan_32x32_neighbors);
michael@0	357	}