1package brotli 2 3/* Lookup table to map the previous two bytes to a context id. 4 5There are four different context modeling modes defined here: 6 contextLSB6: context id is the least significant 6 bits of the last byte, 7 contextMSB6: context id is the most significant 6 bits of the last byte, 8 contextUTF8: second-order context model tuned for UTF8-encoded text, 9 contextSigned: second-order context model tuned for signed integers. 10 11If |p1| and |p2| are the previous two bytes, and |mode| is current context 12mode, we calculate the context as: 13 14 context = ContextLut(mode)[p1] | ContextLut(mode)[p2 + 256]. 15 16For contextUTF8 mode, if the previous two bytes are ASCII characters 17(i.e. < 128), this will be equivalent to 18 19 context = 4 * context1(p1) + context2(p2), 20 21where context1 is based on the previous byte in the following way: 22 23 0 : non-ASCII control 24 1 : \t, \n, \r 25 2 : space 26 3 : other punctuation 27 4 : " ' 28 5 : % 29 6 : ( < [ { 30 7 : ) > ] } 31 8 : , ; : 32 9 : . 33 10 : = 34 11 : number 35 12 : upper-case vowel 36 13 : upper-case consonant 37 14 : lower-case vowel 38 15 : lower-case consonant 39 40and context2 is based on the second last byte: 41 42 0 : control, space 43 1 : punctuation 44 2 : upper-case letter, number 45 3 : lower-case letter 46 47If the last byte is ASCII, and the second last byte is not (in a valid UTF8 48stream it will be a continuation byte, value between 128 and 191), the 49context is the same as if the second last byte was an ASCII control or space. 50 51If the last byte is a UTF8 lead byte (value >= 192), then the next byte will 52be a continuation byte and the context id is 2 or 3 depending on the LSB of 53the last byte and to a lesser extent on the second last byte if it is ASCII. 54 55If the last byte is a UTF8 continuation byte, the second last byte can be: 56 - continuation byte: the next byte is probably ASCII or lead byte (assuming 57 4-byte UTF8 characters are rare) and the context id is 0 or 1. 58 - lead byte (192 - 207): next byte is ASCII or lead byte, context is 0 or 1 59 - lead byte (208 - 255): next byte is continuation byte, context is 2 or 3 60 61The possible value combinations of the previous two bytes, the range of 62context ids and the type of the next byte is summarized in the table below: 63 64|--------\-----------------------------------------------------------------| 65| \ Last byte | 66| Second \---------------------------------------------------------------| 67| last byte \ ASCII | cont. byte | lead byte | 68| \ (0-127) | (128-191) | (192-) | 69|=============|===================|=====================|==================| 70| ASCII | next: ASCII/lead | not valid | next: cont. | 71| (0-127) | context: 4 - 63 | | context: 2 - 3 | 72|-------------|-------------------|---------------------|------------------| 73| cont. byte | next: ASCII/lead | next: ASCII/lead | next: cont. | 74| (128-191) | context: 4 - 63 | context: 0 - 1 | context: 2 - 3 | 75|-------------|-------------------|---------------------|------------------| 76| lead byte | not valid | next: ASCII/lead | not valid | 77| (192-207) | | context: 0 - 1 | | 78|-------------|-------------------|---------------------|------------------| 79| lead byte | not valid | next: cont. | not valid | 80| (208-) | | context: 2 - 3 | | 81|-------------|-------------------|---------------------|------------------| 82*/ 83 84const ( 85 contextLSB6 = 0 86 contextMSB6 = 1 87 contextUTF8 = 2 88 contextSigned = 3 89) 90 91/* Common context lookup table for all context modes. */ 92var kContextLookup = [2048]byte{ 93 /* CONTEXT_LSB6, last byte. */ 94 0, 95 1, 96 2, 97 3, 98 4, 99 5, 100 6, 101 7, 102 8, 103 9, 104 10, 105 11, 106 12, 107 13, 108 14, 109 15, 110 16, 111 17, 112 18, 113 19, 114 20, 115 21, 116 22, 117 23, 118 24, 119 25, 120 26, 121 27, 122 28, 123 29, 124 30, 125 31, 126 32, 127 33, 128 34, 129 35, 130 36, 131 37, 132 38, 133 39, 134 40, 135 41, 136 42, 137 43, 138 44, 139 45, 140 46, 141 47, 142 48, 143 49, 144 50, 145 51, 146 52, 147 53, 148 54, 149 55, 150 56, 151 57, 152 58, 153 59, 154 60, 155 61, 156 62, 157 63, 158 0, 159 1, 160 2, 161 3, 162 4, 163 5, 164 6, 165 7, 166 8, 167 9, 168 10, 169 11, 170 12, 171 13, 172 14, 173 15, 174 16, 175 17, 176 18, 177 19, 178 20, 179 21, 180 22, 181 23, 182 24, 183 25, 184 26, 185 27, 186 28, 187 29, 188 30, 189 31, 190 32, 191 33, 192 34, 193 35, 194 36, 195 37, 196 38, 197 39, 198 40, 199 41, 200 42, 201 43, 202 44, 203 45, 204 46, 205 47, 206 48, 207 49, 208 50, 209 51, 210 52, 211 53, 212 54, 213 55, 214 56, 215 57, 216 58, 217 59, 218 60, 219 61, 220 62, 221 63, 222 0, 223 1, 224 2, 225 3, 226 4, 227 5, 228 6, 229 7, 230 8, 231 9, 232 10, 233 11, 234 12, 235 13, 236 14, 237 15, 238 16, 239 17, 240 18, 241 19, 242 20, 243 21, 244 22, 245 23, 246 24, 247 25, 248 26, 249 27, 250 28, 251 29, 252 30, 253 31, 254 32, 255 33, 256 34, 257 35, 258 36, 259 37, 260 38, 261 39, 262 40, 263 41, 264 42, 265 43, 266 44, 267 45, 268 46, 269 47, 270 48, 271 49, 272 50, 273 51, 274 52, 275 53, 276 54, 277 55, 278 56, 279 57, 280 58, 281 59, 282 60, 283 61, 284 62, 285 63, 286 0, 287 1, 288 2, 289 3, 290 4, 291 5, 292 6, 293 7, 294 8, 295 9, 296 10, 297 11, 298 12, 299 13, 300 14, 301 15, 302 16, 303 17, 304 18, 305 19, 306 20, 307 21, 308 22, 309 23, 310 24, 311 25, 312 26, 313 27, 314 28, 315 29, 316 30, 317 31, 318 32, 319 33, 320 34, 321 35, 322 36, 323 37, 324 38, 325 39, 326 40, 327 41, 328 42, 329 43, 330 44, 331 45, 332 46, 333 47, 334 48, 335 49, 336 50, 337 51, 338 52, 339 53, 340 54, 341 55, 342 56, 343 57, 344 58, 345 59, 346 60, 347 61, 348 62, 349 63, 350 351 /* CONTEXT_LSB6, second last byte, */ 352 0, 353 0, 354 0, 355 0, 356 0, 357 0, 358 0, 359 0, 360 0, 361 0, 362 0, 363 0, 364 0, 365 0, 366 0, 367 0, 368 0, 369 0, 370 0, 371 0, 372 0, 373 0, 374 0, 375 0, 376 0, 377 0, 378 0, 379 0, 380 0, 381 0, 382 0, 383 0, 384 0, 385 0, 386 0, 387 0, 388 0, 389 0, 390 0, 391 0, 392 0, 393 0, 394 0, 395 0, 396 0, 397 0, 398 0, 399 0, 400 0, 401 0, 402 0, 403 0, 404 0, 405 0, 406 0, 407 0, 408 0, 409 0, 410 0, 411 0, 412 0, 413 0, 414 0, 415 0, 416 0, 417 0, 418 0, 419 0, 420 0, 421 0, 422 0, 423 0, 424 0, 425 0, 426 0, 427 0, 428 0, 429 0, 430 0, 431 0, 432 0, 433 0, 434 0, 435 0, 436 0, 437 0, 438 0, 439 0, 440 0, 441 0, 442 0, 443 0, 444 0, 445 0, 446 0, 447 0, 448 0, 449 0, 450 0, 451 0, 452 0, 453 0, 454 0, 455 0, 456 0, 457 0, 458 0, 459 0, 460 0, 461 0, 462 0, 463 0, 464 0, 465 0, 466 0, 467 0, 468 0, 469 0, 470 0, 471 0, 472 0, 473 0, 474 0, 475 0, 476 0, 477 0, 478 0, 479 0, 480 0, 481 0, 482 0, 483 0, 484 0, 485 0, 486 0, 487 0, 488 0, 489 0, 490 0, 491 0, 492 0, 493 0, 494 0, 495 0, 496 0, 497 0, 498 0, 499 0, 500 0, 501 0, 502 0, 503 0, 504 0, 505 0, 506 0, 507 0, 508 0, 509 0, 510 0, 511 0, 512 0, 513 0, 514 0, 515 0, 516 0, 517 0, 518 0, 519 0, 520 0, 521 0, 522 0, 523 0, 524 0, 525 0, 526 0, 527 0, 528 0, 529 0, 530 0, 531 0, 532 0, 533 0, 534 0, 535 0, 536 0, 537 0, 538 0, 539 0, 540 0, 541 0, 542 0, 543 0, 544 0, 545 0, 546 0, 547 0, 548 0, 549 0, 550 0, 551 0, 552 0, 553 0, 554 0, 555 0, 556 0, 557 0, 558 0, 559 0, 560 0, 561 0, 562 0, 563 0, 564 0, 565 0, 566 0, 567 0, 568 0, 569 0, 570 0, 571 0, 572 0, 573 0, 574 0, 575 0, 576 0, 577 0, 578 0, 579 0, 580 0, 581 0, 582 0, 583 0, 584 0, 585 0, 586 0, 587 0, 588 0, 589 0, 590 0, 591 0, 592 0, 593 0, 594 0, 595 0, 596 0, 597 0, 598 0, 599 0, 600 0, 601 0, 602 0, 603 0, 604 0, 605 0, 606 0, 607 0, 608 609 /* CONTEXT_MSB6, last byte. */ 610 0, 611 0, 612 0, 613 0, 614 1, 615 1, 616 1, 617 1, 618 2, 619 2, 620 2, 621 2, 622 3, 623 3, 624 3, 625 3, 626 4, 627 4, 628 4, 629 4, 630 5, 631 5, 632 5, 633 5, 634 6, 635 6, 636 6, 637 6, 638 7, 639 7, 640 7, 641 7, 642 8, 643 8, 644 8, 645 8, 646 9, 647 9, 648 9, 649 9, 650 10, 651 10, 652 10, 653 10, 654 11, 655 11, 656 11, 657 11, 658 12, 659 12, 660 12, 661 12, 662 13, 663 13, 664 13, 665 13, 666 14, 667 14, 668 14, 669 14, 670 15, 671 15, 672 15, 673 15, 674 16, 675 16, 676 16, 677 16, 678 17, 679 17, 680 17, 681 17, 682 18, 683 18, 684 18, 685 18, 686 19, 687 19, 688 19, 689 19, 690 20, 691 20, 692 20, 693 20, 694 21, 695 21, 696 21, 697 21, 698 22, 699 22, 700 22, 701 22, 702 23, 703 23, 704 23, 705 23, 706 24, 707 24, 708 24, 709 24, 710 25, 711 25, 712 25, 713 25, 714 26, 715 26, 716 26, 717 26, 718 27, 719 27, 720 27, 721 27, 722 28, 723 28, 724 28, 725 28, 726 29, 727 29, 728 29, 729 29, 730 30, 731 30, 732 30, 733 30, 734 31, 735 31, 736 31, 737 31, 738 32, 739 32, 740 32, 741 32, 742 33, 743 33, 744 33, 745 33, 746 34, 747 34, 748 34, 749 34, 750 35, 751 35, 752 35, 753 35, 754 36, 755 36, 756 36, 757 36, 758 37, 759 37, 760 37, 761 37, 762 38, 763 38, 764 38, 765 38, 766 39, 767 39, 768 39, 769 39, 770 40, 771 40, 772 40, 773 40, 774 41, 775 41, 776 41, 777 41, 778 42, 779 42, 780 42, 781 42, 782 43, 783 43, 784 43, 785 43, 786 44, 787 44, 788 44, 789 44, 790 45, 791 45, 792 45, 793 45, 794 46, 795 46, 796 46, 797 46, 798 47, 799 47, 800 47, 801 47, 802 48, 803 48, 804 48, 805 48, 806 49, 807 49, 808 49, 809 49, 810 50, 811 50, 812 50, 813 50, 814 51, 815 51, 816 51, 817 51, 818 52, 819 52, 820 52, 821 52, 822 53, 823 53, 824 53, 825 53, 826 54, 827 54, 828 54, 829 54, 830 55, 831 55, 832 55, 833 55, 834 56, 835 56, 836 56, 837 56, 838 57, 839 57, 840 57, 841 57, 842 58, 843 58, 844 58, 845 58, 846 59, 847 59, 848 59, 849 59, 850 60, 851 60, 852 60, 853 60, 854 61, 855 61, 856 61, 857 61, 858 62, 859 62, 860 62, 861 62, 862 63, 863 63, 864 63, 865 63, 866 867 /* CONTEXT_MSB6, second last byte, */ 868 0, 869 0, 870 0, 871 0, 872 0, 873 0, 874 0, 875 0, 876 0, 877 0, 878 0, 879 0, 880 0, 881 0, 882 0, 883 0, 884 0, 885 0, 886 0, 887 0, 888 0, 889 0, 890 0, 891 0, 892 0, 893 0, 894 0, 895 0, 896 0, 897 0, 898 0, 899 0, 900 0, 901 0, 902 0, 903 0, 904 0, 905 0, 906 0, 907 0, 908 0, 909 0, 910 0, 911 0, 912 0, 913 0, 914 0, 915 0, 916 0, 917 0, 918 0, 919 0, 920 0, 921 0, 922 0, 923 0, 924 0, 925 0, 926 0, 927 0, 928 0, 929 0, 930 0, 931 0, 932 0, 933 0, 934 0, 935 0, 936 0, 937 0, 938 0, 939 0, 940 0, 941 0, 942 0, 943 0, 944 0, 945 0, 946 0, 947 0, 948 0, 949 0, 950 0, 951 0, 952 0, 953 0, 954 0, 955 0, 956 0, 957 0, 958 0, 959 0, 960 0, 961 0, 962 0, 963 0, 964 0, 965 0, 966 0, 967 0, 968 0, 969 0, 970 0, 971 0, 972 0, 973 0, 974 0, 975 0, 976 0, 977 0, 978 0, 979 0, 980 0, 981 0, 982 0, 983 0, 984 0, 985 0, 986 0, 987 0, 988 0, 989 0, 990 0, 991 0, 992 0, 993 0, 994 0, 995 0, 996 0, 997 0, 998 0, 999 0, 1000 0, 1001 0, 1002 0, 1003 0, 1004 0, 1005 0, 1006 0, 1007 0, 1008 0, 1009 0, 1010 0, 1011 0, 1012 0, 1013 0, 1014 0, 1015 0, 1016 0, 1017 0, 1018 0, 1019 0, 1020 0, 1021 0, 1022 0, 1023 0, 1024 0, 1025 0, 1026 0, 1027 0, 1028 0, 1029 0, 1030 0, 1031 0, 1032 0, 1033 0, 1034 0, 1035 0, 1036 0, 1037 0, 1038 0, 1039 0, 1040 0, 1041 0, 1042 0, 1043 0, 1044 0, 1045 0, 1046 0, 1047 0, 1048 0, 1049 0, 1050 0, 1051 0, 1052 0, 1053 0, 1054 0, 1055 0, 1056 0, 1057 0, 1058 0, 1059 0, 1060 0, 1061 0, 1062 0, 1063 0, 1064 0, 1065 0, 1066 0, 1067 0, 1068 0, 1069 0, 1070 0, 1071 0, 1072 0, 1073 0, 1074 0, 1075 0, 1076 0, 1077 0, 1078 0, 1079 0, 1080 0, 1081 0, 1082 0, 1083 0, 1084 0, 1085 0, 1086 0, 1087 0, 1088 0, 1089 0, 1090 0, 1091 0, 1092 0, 1093 0, 1094 0, 1095 0, 1096 0, 1097 0, 1098 0, 1099 0, 1100 0, 1101 0, 1102 0, 1103 0, 1104 0, 1105 0, 1106 0, 1107 0, 1108 0, 1109 0, 1110 0, 1111 0, 1112 0, 1113 0, 1114 0, 1115 0, 1116 0, 1117 0, 1118 0, 1119 0, 1120 0, 1121 0, 1122 0, 1123 0, 1124 1125 /* CONTEXT_UTF8, last byte. */ 1126 /* ASCII range. */ 1127 0, 1128 0, 1129 0, 1130 0, 1131 0, 1132 0, 1133 0, 1134 0, 1135 0, 1136 4, 1137 4, 1138 0, 1139 0, 1140 4, 1141 0, 1142 0, 1143 0, 1144 0, 1145 0, 1146 0, 1147 0, 1148 0, 1149 0, 1150 0, 1151 0, 1152 0, 1153 0, 1154 0, 1155 0, 1156 0, 1157 0, 1158 0, 1159 8, 1160 12, 1161 16, 1162 12, 1163 12, 1164 20, 1165 12, 1166 16, 1167 24, 1168 28, 1169 12, 1170 12, 1171 32, 1172 12, 1173 36, 1174 12, 1175 44, 1176 44, 1177 44, 1178 44, 1179 44, 1180 44, 1181 44, 1182 44, 1183 44, 1184 44, 1185 32, 1186 32, 1187 24, 1188 40, 1189 28, 1190 12, 1191 12, 1192 48, 1193 52, 1194 52, 1195 52, 1196 48, 1197 52, 1198 52, 1199 52, 1200 48, 1201 52, 1202 52, 1203 52, 1204 52, 1205 52, 1206 48, 1207 52, 1208 52, 1209 52, 1210 52, 1211 52, 1212 48, 1213 52, 1214 52, 1215 52, 1216 52, 1217 52, 1218 24, 1219 12, 1220 28, 1221 12, 1222 12, 1223 12, 1224 56, 1225 60, 1226 60, 1227 60, 1228 56, 1229 60, 1230 60, 1231 60, 1232 56, 1233 60, 1234 60, 1235 60, 1236 60, 1237 60, 1238 56, 1239 60, 1240 60, 1241 60, 1242 60, 1243 60, 1244 56, 1245 60, 1246 60, 1247 60, 1248 60, 1249 60, 1250 24, 1251 12, 1252 28, 1253 12, 1254 0, 1255 1256 /* UTF8 continuation byte range. */ 1257 0, 1258 1, 1259 0, 1260 1, 1261 0, 1262 1, 1263 0, 1264 1, 1265 0, 1266 1, 1267 0, 1268 1, 1269 0, 1270 1, 1271 0, 1272 1, 1273 0, 1274 1, 1275 0, 1276 1, 1277 0, 1278 1, 1279 0, 1280 1, 1281 0, 1282 1, 1283 0, 1284 1, 1285 0, 1286 1, 1287 0, 1288 1, 1289 0, 1290 1, 1291 0, 1292 1, 1293 0, 1294 1, 1295 0, 1296 1, 1297 0, 1298 1, 1299 0, 1300 1, 1301 0, 1302 1, 1303 0, 1304 1, 1305 0, 1306 1, 1307 0, 1308 1, 1309 0, 1310 1, 1311 0, 1312 1, 1313 0, 1314 1, 1315 0, 1316 1, 1317 0, 1318 1, 1319 0, 1320 1, 1321 1322 /* UTF8 lead byte range. */ 1323 2, 1324 3, 1325 2, 1326 3, 1327 2, 1328 3, 1329 2, 1330 3, 1331 2, 1332 3, 1333 2, 1334 3, 1335 2, 1336 3, 1337 2, 1338 3, 1339 2, 1340 3, 1341 2, 1342 3, 1343 2, 1344 3, 1345 2, 1346 3, 1347 2, 1348 3, 1349 2, 1350 3, 1351 2, 1352 3, 1353 2, 1354 3, 1355 2, 1356 3, 1357 2, 1358 3, 1359 2, 1360 3, 1361 2, 1362 3, 1363 2, 1364 3, 1365 2, 1366 3, 1367 2, 1368 3, 1369 2, 1370 3, 1371 2, 1372 3, 1373 2, 1374 3, 1375 2, 1376 3, 1377 2, 1378 3, 1379 2, 1380 3, 1381 2, 1382 3, 1383 2, 1384 3, 1385 2, 1386 3, 1387 1388 /* CONTEXT_UTF8 second last byte. */ 1389 /* ASCII range. */ 1390 0, 1391 0, 1392 0, 1393 0, 1394 0, 1395 0, 1396 0, 1397 0, 1398 0, 1399 0, 1400 0, 1401 0, 1402 0, 1403 0, 1404 0, 1405 0, 1406 0, 1407 0, 1408 0, 1409 0, 1410 0, 1411 0, 1412 0, 1413 0, 1414 0, 1415 0, 1416 0, 1417 0, 1418 0, 1419 0, 1420 0, 1421 0, 1422 0, 1423 1, 1424 1, 1425 1, 1426 1, 1427 1, 1428 1, 1429 1, 1430 1, 1431 1, 1432 1, 1433 1, 1434 1, 1435 1, 1436 1, 1437 1, 1438 2, 1439 2, 1440 2, 1441 2, 1442 2, 1443 2, 1444 2, 1445 2, 1446 2, 1447 2, 1448 1, 1449 1, 1450 1, 1451 1, 1452 1, 1453 1, 1454 1, 1455 2, 1456 2, 1457 2, 1458 2, 1459 2, 1460 2, 1461 2, 1462 2, 1463 2, 1464 2, 1465 2, 1466 2, 1467 2, 1468 2, 1469 2, 1470 2, 1471 2, 1472 2, 1473 2, 1474 2, 1475 2, 1476 2, 1477 2, 1478 2, 1479 2, 1480 2, 1481 1, 1482 1, 1483 1, 1484 1, 1485 1, 1486 1, 1487 3, 1488 3, 1489 3, 1490 3, 1491 3, 1492 3, 1493 3, 1494 3, 1495 3, 1496 3, 1497 3, 1498 3, 1499 3, 1500 3, 1501 3, 1502 3, 1503 3, 1504 3, 1505 3, 1506 3, 1507 3, 1508 3, 1509 3, 1510 3, 1511 3, 1512 3, 1513 1, 1514 1, 1515 1, 1516 1, 1517 0, 1518 1519 /* UTF8 continuation byte range. */ 1520 0, 1521 0, 1522 0, 1523 0, 1524 0, 1525 0, 1526 0, 1527 0, 1528 0, 1529 0, 1530 0, 1531 0, 1532 0, 1533 0, 1534 0, 1535 0, 1536 0, 1537 0, 1538 0, 1539 0, 1540 0, 1541 0, 1542 0, 1543 0, 1544 0, 1545 0, 1546 0, 1547 0, 1548 0, 1549 0, 1550 0, 1551 0, 1552 0, 1553 0, 1554 0, 1555 0, 1556 0, 1557 0, 1558 0, 1559 0, 1560 0, 1561 0, 1562 0, 1563 0, 1564 0, 1565 0, 1566 0, 1567 0, 1568 0, 1569 0, 1570 0, 1571 0, 1572 0, 1573 0, 1574 0, 1575 0, 1576 0, 1577 0, 1578 0, 1579 0, 1580 0, 1581 0, 1582 0, 1583 0, 1584 0, 1585 0, 1586 0, 1587 0, 1588 0, 1589 0, 1590 0, 1591 0, 1592 0, 1593 0, 1594 0, 1595 0, 1596 0, 1597 0, 1598 0, 1599 0, 1600 1601 /* UTF8 lead byte range. */ 1602 0, 1603 0, 1604 0, 1605 0, 1606 0, 1607 0, 1608 0, 1609 0, 1610 0, 1611 0, 1612 0, 1613 0, 1614 0, 1615 0, 1616 0, 1617 0, 1618 2, 1619 2, 1620 2, 1621 2, 1622 2, 1623 2, 1624 2, 1625 2, 1626 2, 1627 2, 1628 2, 1629 2, 1630 2, 1631 2, 1632 2, 1633 2, 1634 2, 1635 2, 1636 2, 1637 2, 1638 2, 1639 2, 1640 2, 1641 2, 1642 2, 1643 2, 1644 2, 1645 2, 1646 2, 1647 2, 1648 2, 1649 2, 1650 1651 /* CONTEXT_SIGNED, last byte, same as the above values shifted by 3 bits. */ 1652 0, 1653 8, 1654 8, 1655 8, 1656 8, 1657 8, 1658 8, 1659 8, 1660 8, 1661 8, 1662 8, 1663 8, 1664 8, 1665 8, 1666 8, 1667 8, 1668 16, 1669 16, 1670 16, 1671 16, 1672 16, 1673 16, 1674 16, 1675 16, 1676 16, 1677 16, 1678 16, 1679 16, 1680 16, 1681 16, 1682 16, 1683 16, 1684 16, 1685 16, 1686 16, 1687 16, 1688 16, 1689 16, 1690 16, 1691 16, 1692 16, 1693 16, 1694 16, 1695 16, 1696 16, 1697 16, 1698 16, 1699 16, 1700 16, 1701 16, 1702 16, 1703 16, 1704 16, 1705 16, 1706 16, 1707 16, 1708 16, 1709 16, 1710 16, 1711 16, 1712 16, 1713 16, 1714 16, 1715 16, 1716 24, 1717 24, 1718 24, 1719 24, 1720 24, 1721 24, 1722 24, 1723 24, 1724 24, 1725 24, 1726 24, 1727 24, 1728 24, 1729 24, 1730 24, 1731 24, 1732 24, 1733 24, 1734 24, 1735 24, 1736 24, 1737 24, 1738 24, 1739 24, 1740 24, 1741 24, 1742 24, 1743 24, 1744 24, 1745 24, 1746 24, 1747 24, 1748 24, 1749 24, 1750 24, 1751 24, 1752 24, 1753 24, 1754 24, 1755 24, 1756 24, 1757 24, 1758 24, 1759 24, 1760 24, 1761 24, 1762 24, 1763 24, 1764 24, 1765 24, 1766 24, 1767 24, 1768 24, 1769 24, 1770 24, 1771 24, 1772 24, 1773 24, 1774 24, 1775 24, 1776 24, 1777 24, 1778 24, 1779 24, 1780 32, 1781 32, 1782 32, 1783 32, 1784 32, 1785 32, 1786 32, 1787 32, 1788 32, 1789 32, 1790 32, 1791 32, 1792 32, 1793 32, 1794 32, 1795 32, 1796 32, 1797 32, 1798 32, 1799 32, 1800 32, 1801 32, 1802 32, 1803 32, 1804 32, 1805 32, 1806 32, 1807 32, 1808 32, 1809 32, 1810 32, 1811 32, 1812 32, 1813 32, 1814 32, 1815 32, 1816 32, 1817 32, 1818 32, 1819 32, 1820 32, 1821 32, 1822 32, 1823 32, 1824 32, 1825 32, 1826 32, 1827 32, 1828 32, 1829 32, 1830 32, 1831 32, 1832 32, 1833 32, 1834 32, 1835 32, 1836 32, 1837 32, 1838 32, 1839 32, 1840 32, 1841 32, 1842 32, 1843 32, 1844 40, 1845 40, 1846 40, 1847 40, 1848 40, 1849 40, 1850 40, 1851 40, 1852 40, 1853 40, 1854 40, 1855 40, 1856 40, 1857 40, 1858 40, 1859 40, 1860 40, 1861 40, 1862 40, 1863 40, 1864 40, 1865 40, 1866 40, 1867 40, 1868 40, 1869 40, 1870 40, 1871 40, 1872 40, 1873 40, 1874 40, 1875 40, 1876 40, 1877 40, 1878 40, 1879 40, 1880 40, 1881 40, 1882 40, 1883 40, 1884 40, 1885 40, 1886 40, 1887 40, 1888 40, 1889 40, 1890 40, 1891 40, 1892 48, 1893 48, 1894 48, 1895 48, 1896 48, 1897 48, 1898 48, 1899 48, 1900 48, 1901 48, 1902 48, 1903 48, 1904 48, 1905 48, 1906 48, 1907 56, 1908 1909 /* CONTEXT_SIGNED, second last byte. */ 1910 0, 1911 1, 1912 1, 1913 1, 1914 1, 1915 1, 1916 1, 1917 1, 1918 1, 1919 1, 1920 1, 1921 1, 1922 1, 1923 1, 1924 1, 1925 1, 1926 2, 1927 2, 1928 2, 1929 2, 1930 2, 1931 2, 1932 2, 1933 2, 1934 2, 1935 2, 1936 2, 1937 2, 1938 2, 1939 2, 1940 2, 1941 2, 1942 2, 1943 2, 1944 2, 1945 2, 1946 2, 1947 2, 1948 2, 1949 2, 1950 2, 1951 2, 1952 2, 1953 2, 1954 2, 1955 2, 1956 2, 1957 2, 1958 2, 1959 2, 1960 2, 1961 2, 1962 2, 1963 2, 1964 2, 1965 2, 1966 2, 1967 2, 1968 2, 1969 2, 1970 2, 1971 2, 1972 2, 1973 2, 1974 3, 1975 3, 1976 3, 1977 3, 1978 3, 1979 3, 1980 3, 1981 3, 1982 3, 1983 3, 1984 3, 1985 3, 1986 3, 1987 3, 1988 3, 1989 3, 1990 3, 1991 3, 1992 3, 1993 3, 1994 3, 1995 3, 1996 3, 1997 3, 1998 3, 1999 3, 2000 3, 2001 3, 2002 3, 2003 3, 2004 3, 2005 3, 2006 3, 2007 3, 2008 3, 2009 3, 2010 3, 2011 3, 2012 3, 2013 3, 2014 3, 2015 3, 2016 3, 2017 3, 2018 3, 2019 3, 2020 3, 2021 3, 2022 3, 2023 3, 2024 3, 2025 3, 2026 3, 2027 3, 2028 3, 2029 3, 2030 3, 2031 3, 2032 3, 2033 3, 2034 3, 2035 3, 2036 3, 2037 3, 2038 4, 2039 4, 2040 4, 2041 4, 2042 4, 2043 4, 2044 4, 2045 4, 2046 4, 2047 4, 2048 4, 2049 4, 2050 4, 2051 4, 2052 4, 2053 4, 2054 4, 2055 4, 2056 4, 2057 4, 2058 4, 2059 4, 2060 4, 2061 4, 2062 4, 2063 4, 2064 4, 2065 4, 2066 4, 2067 4, 2068 4, 2069 4, 2070 4, 2071 4, 2072 4, 2073 4, 2074 4, 2075 4, 2076 4, 2077 4, 2078 4, 2079 4, 2080 4, 2081 4, 2082 4, 2083 4, 2084 4, 2085 4, 2086 4, 2087 4, 2088 4, 2089 4, 2090 4, 2091 4, 2092 4, 2093 4, 2094 4, 2095 4, 2096 4, 2097 4, 2098 4, 2099 4, 2100 4, 2101 4, 2102 5, 2103 5, 2104 5, 2105 5, 2106 5, 2107 5, 2108 5, 2109 5, 2110 5, 2111 5, 2112 5, 2113 5, 2114 5, 2115 5, 2116 5, 2117 5, 2118 5, 2119 5, 2120 5, 2121 5, 2122 5, 2123 5, 2124 5, 2125 5, 2126 5, 2127 5, 2128 5, 2129 5, 2130 5, 2131 5, 2132 5, 2133 5, 2134 5, 2135 5, 2136 5, 2137 5, 2138 5, 2139 5, 2140 5, 2141 5, 2142 5, 2143 5, 2144 5, 2145 5, 2146 5, 2147 5, 2148 5, 2149 5, 2150 6, 2151 6, 2152 6, 2153 6, 2154 6, 2155 6, 2156 6, 2157 6, 2158 6, 2159 6, 2160 6, 2161 6, 2162 6, 2163 6, 2164 6, 2165 7, 2166} 2167 2168type contextLUT []byte 2169 2170func getContextLUT(mode int) contextLUT { 2171 return kContextLookup[mode<<9:] 2172} 2173 2174func getContext(p1 byte, p2 byte, lut contextLUT) byte { 2175 return lut[p1] | lut[256+int(p2)] 2176} 2177