| /* Copyright 2015 Google Inc. All Rights Reserved. |
| |
| Distributed under MIT license. |
| See file LICENSE for detail or copy at https://opensource.org/licenses/MIT |
| */ |
| |
| package org.brotli.dec; |
| |
| /** |
| * Common context lookup table for all context modes. |
| */ |
| final class Context { |
| |
| static final int[] LOOKUP = new int[2048]; |
| |
| private static final String UTF_MAP = " !! ! \"#$##%#$&'##(#)#+++++++++" |
| + "+((&*'##,---,---,-----,-----,-----&#'###.///.///./////./////./////&#'# "; |
| private static final String UTF_RLE = "A/* ': & : $ \u0081 @"; |
| |
| private static void unpackLookupTable(int[] lookup, String map, String rle) { |
| // LSB6, MSB6, SIGNED |
| for (int i = 0; i < 256; ++i) { |
| lookup[i] = i & 0x3F; |
| lookup[512 + i] = i >> 2; |
| lookup[1792 + i] = 2 + (i >> 6); |
| } |
| // UTF8 |
| for (int i = 0; i < 128; ++i) { |
| lookup[1024 + i] = 4 * (map.charAt(i) - 32); |
| } |
| for (int i = 0; i < 64; ++i) { |
| lookup[1152 + i] = i & 1; |
| lookup[1216 + i] = 2 + (i & 1); |
| } |
| int offset = 1280; |
| for (int k = 0; k < 19; ++k) { |
| int value = k & 3; |
| int rep = rle.charAt(k) - 32; |
| for (int i = 0; i < rep; ++i) { |
| lookup[offset++] = value; |
| } |
| } |
| // SIGNED |
| for (int i = 0; i < 16; ++i) { |
| lookup[1792 + i] = 1; |
| lookup[2032 + i] = 6; |
| } |
| lookup[1792] = 0; |
| lookup[2047] = 7; |
| for (int i = 0; i < 256; ++i) { |
| lookup[1536 + i] = lookup[1792 + i] << 3; |
| } |
| } |
| |
| static { |
| unpackLookupTable(LOOKUP, UTF_MAP, UTF_RLE); |
| } |
| } |