| // |
| // ======================================================================== |
| // Copyright (c) 1995-2016 Mort Bay Consulting Pty. Ltd. |
| // ------------------------------------------------------------------------ |
| // All rights reserved. This program and the accompanying materials |
| // are made available under the terms of the Eclipse Public License v1.0 |
| // and Apache License v2.0 which accompanies this distribution. |
| // |
| // The Eclipse Public License is available at |
| // http://www.eclipse.org/legal/epl-v10.html |
| // |
| // The Apache License v2.0 is available at |
| // http://www.opensource.org/licenses/apache2.0.php |
| // |
| // You may elect to redistribute this code under either of these licenses. |
| // ======================================================================== |
| // |
| |
| package org.eclipse.jetty.http2.hpack; |
| |
| import java.nio.ByteBuffer; |
| |
| public class Huffman |
| { |
| |
| // Appendix C: Huffman Codes |
| // http://tools.ietf.org/html/draft-ietf-httpbis-header-compression-12#appendix-C |
| static final int[][] CODES = |
| { |
| /* ( 0) |11111111|11000 */ {0x1ff8,13}, |
| /* ( 1) |11111111|11111111|1011000 */ {0x7fffd8,23}, |
| /* ( 2) |11111111|11111111|11111110|0010 */ {0xfffffe2,28}, |
| /* ( 3) |11111111|11111111|11111110|0011 */ {0xfffffe3,28}, |
| /* ( 4) |11111111|11111111|11111110|0100 */ {0xfffffe4,28}, |
| /* ( 5) |11111111|11111111|11111110|0101 */ {0xfffffe5,28}, |
| /* ( 6) |11111111|11111111|11111110|0110 */ {0xfffffe6,28}, |
| /* ( 7) |11111111|11111111|11111110|0111 */ {0xfffffe7,28}, |
| /* ( 8) |11111111|11111111|11111110|1000 */ {0xfffffe8,28}, |
| /* ( 9) |11111111|11111111|11101010 */ {0xffffea,24}, |
| /* ( 10) |11111111|11111111|11111111|111100 */ {0x3ffffffc,30}, |
| /* ( 11) |11111111|11111111|11111110|1001 */ {0xfffffe9,28}, |
| /* ( 12) |11111111|11111111|11111110|1010 */ {0xfffffea,28}, |
| /* ( 13) |11111111|11111111|11111111|111101 */ {0x3ffffffd,30}, |
| /* ( 14) |11111111|11111111|11111110|1011 */ {0xfffffeb,28}, |
| /* ( 15) |11111111|11111111|11111110|1100 */ {0xfffffec,28}, |
| /* ( 16) |11111111|11111111|11111110|1101 */ {0xfffffed,28}, |
| /* ( 17) |11111111|11111111|11111110|1110 */ {0xfffffee,28}, |
| /* ( 18) |11111111|11111111|11111110|1111 */ {0xfffffef,28}, |
| /* ( 19) |11111111|11111111|11111111|0000 */ {0xffffff0,28}, |
| /* ( 20) |11111111|11111111|11111111|0001 */ {0xffffff1,28}, |
| /* ( 21) |11111111|11111111|11111111|0010 */ {0xffffff2,28}, |
| /* ( 22) |11111111|11111111|11111111|111110 */ {0x3ffffffe,30}, |
| /* ( 23) |11111111|11111111|11111111|0011 */ {0xffffff3,28}, |
| /* ( 24) |11111111|11111111|11111111|0100 */ {0xffffff4,28}, |
| /* ( 25) |11111111|11111111|11111111|0101 */ {0xffffff5,28}, |
| /* ( 26) |11111111|11111111|11111111|0110 */ {0xffffff6,28}, |
| /* ( 27) |11111111|11111111|11111111|0111 */ {0xffffff7,28}, |
| /* ( 28) |11111111|11111111|11111111|1000 */ {0xffffff8,28}, |
| /* ( 29) |11111111|11111111|11111111|1001 */ {0xffffff9,28}, |
| /* ( 30) |11111111|11111111|11111111|1010 */ {0xffffffa,28}, |
| /* ( 31) |11111111|11111111|11111111|1011 */ {0xffffffb,28}, |
| /*' ' ( 32) |010100 */ {0x14, 6}, |
| /*'!' ( 33) |11111110|00 */ {0x3f8,10}, |
| /*'"' ( 34) |11111110|01 */ {0x3f9,10}, |
| /*'#' ( 35) |11111111|1010 */ {0xffa,12}, |
| /*'$' ( 36) |11111111|11001 */ {0x1ff9,13}, |
| /*'%' ( 37) |010101 */ {0x15, 6}, |
| /*'&' ( 38) |11111000 */ {0xf8, 8}, |
| /*''' ( 39) |11111111|010 */ {0x7fa,11}, |
| /*'(' ( 40) |11111110|10 */ {0x3fa,10}, |
| /*')' ( 41) |11111110|11 */ {0x3fb,10}, |
| /*'*' ( 42) |11111001 */ {0xf9, 8}, |
| /*'+' ( 43) |11111111|011 */ {0x7fb,11}, |
| /*',' ( 44) |11111010 */ {0xfa, 8}, |
| /*'-' ( 45) |010110 */ {0x16, 6}, |
| /*'.' ( 46) |010111 */ {0x17, 6}, |
| /*'/' ( 47) |011000 */ {0x18, 6}, |
| /*'0' ( 48) |00000 */ {0x0, 5}, |
| /*'1' ( 49) |00001 */ {0x1, 5}, |
| /*'2' ( 50) |00010 */ {0x2, 5}, |
| /*'3' ( 51) |011001 */ {0x19, 6}, |
| /*'4' ( 52) |011010 */ {0x1a, 6}, |
| /*'5' ( 53) |011011 */ {0x1b, 6}, |
| /*'6' ( 54) |011100 */ {0x1c, 6}, |
| /*'7' ( 55) |011101 */ {0x1d, 6}, |
| /*'8' ( 56) |011110 */ {0x1e, 6}, |
| /*'9' ( 57) |011111 */ {0x1f, 6}, |
| /*':' ( 58) |1011100 */ {0x5c, 7}, |
| /*';' ( 59) |11111011 */ {0xfb, 8}, |
| /*'<' ( 60) |11111111|1111100 */ {0x7ffc,15}, |
| /*'=' ( 61) |100000 */ {0x20, 6}, |
| /*'>' ( 62) |11111111|1011 */ {0xffb,12}, |
| /*'?' ( 63) |11111111|00 */ {0x3fc,10}, |
| /*'@' ( 64) |11111111|11010 */ {0x1ffa,13}, |
| /*'A' ( 65) |100001 */ {0x21, 6}, |
| /*'B' ( 66) |1011101 */ {0x5d, 7}, |
| /*'C' ( 67) |1011110 */ {0x5e, 7}, |
| /*'D' ( 68) |1011111 */ {0x5f, 7}, |
| /*'E' ( 69) |1100000 */ {0x60, 7}, |
| /*'F' ( 70) |1100001 */ {0x61, 7}, |
| /*'G' ( 71) |1100010 */ {0x62, 7}, |
| /*'H' ( 72) |1100011 */ {0x63, 7}, |
| /*'I' ( 73) |1100100 */ {0x64, 7}, |
| /*'J' ( 74) |1100101 */ {0x65, 7}, |
| /*'K' ( 75) |1100110 */ {0x66, 7}, |
| /*'L' ( 76) |1100111 */ {0x67, 7}, |
| /*'M' ( 77) |1101000 */ {0x68, 7}, |
| /*'N' ( 78) |1101001 */ {0x69, 7}, |
| /*'O' ( 79) |1101010 */ {0x6a, 7}, |
| /*'P' ( 80) |1101011 */ {0x6b, 7}, |
| /*'Q' ( 81) |1101100 */ {0x6c, 7}, |
| /*'R' ( 82) |1101101 */ {0x6d, 7}, |
| /*'S' ( 83) |1101110 */ {0x6e, 7}, |
| /*'T' ( 84) |1101111 */ {0x6f, 7}, |
| /*'U' ( 85) |1110000 */ {0x70, 7}, |
| /*'V' ( 86) |1110001 */ {0x71, 7}, |
| /*'W' ( 87) |1110010 */ {0x72, 7}, |
| /*'X' ( 88) |11111100 */ {0xfc, 8}, |
| /*'Y' ( 89) |1110011 */ {0x73, 7}, |
| /*'Z' ( 90) |11111101 */ {0xfd, 8}, |
| /*'[' ( 91) |11111111|11011 */ {0x1ffb,13}, |
| /*'\' ( 92) |11111111|11111110|000 */ {0x7fff0,19}, |
| /*']' ( 93) |11111111|11100 */ {0x1ffc,13}, |
| /*'^' ( 94) |11111111|111100 */ {0x3ffc,14}, |
| /*'_' ( 95) |100010 */ {0x22, 6}, |
| /*'`' ( 96) |11111111|1111101 */ {0x7ffd,15}, |
| /*'a' ( 97) |00011 */ {0x3, 5}, |
| /*'b' ( 98) |100011 */ {0x23, 6}, |
| /*'c' ( 99) |00100 */ {0x4, 5}, |
| /*'d' (100) |100100 */ {0x24, 6}, |
| /*'e' (101) |00101 */ {0x5, 5}, |
| /*'f' (102) |100101 */ {0x25, 6}, |
| /*'g' (103) |100110 */ {0x26, 6}, |
| /*'h' (104) |100111 */ {0x27, 6}, |
| /*'i' (105) |00110 */ {0x6, 5}, |
| /*'j' (106) |1110100 */ {0x74, 7}, |
| /*'k' (107) |1110101 */ {0x75, 7}, |
| /*'l' (108) |101000 */ {0x28, 6}, |
| /*'m' (109) |101001 */ {0x29, 6}, |
| /*'n' (110) |101010 */ {0x2a, 6}, |
| /*'o' (111) |00111 */ {0x7, 5}, |
| /*'p' (112) |101011 */ {0x2b, 6}, |
| /*'q' (113) |1110110 */ {0x76, 7}, |
| /*'r' (114) |101100 */ {0x2c, 6}, |
| /*'s' (115) |01000 */ {0x8, 5}, |
| /*'t' (116) |01001 */ {0x9, 5}, |
| /*'u' (117) |101101 */ {0x2d, 6}, |
| /*'v' (118) |1110111 */ {0x77, 7}, |
| /*'w' (119) |1111000 */ {0x78, 7}, |
| /*'x' (120) |1111001 */ {0x79, 7}, |
| /*'y' (121) |1111010 */ {0x7a, 7}, |
| /*'z' (122) |1111011 */ {0x7b, 7}, |
| /*'{' (123) |11111111|1111110 */ {0x7ffe,15}, |
| /*'|' (124) |11111111|100 */ {0x7fc,11}, |
| /*'}' (125) |11111111|111101 */ {0x3ffd,14}, |
| /*'~' (126) |11111111|11101 */ {0x1ffd,13}, |
| /* (127) |11111111|11111111|11111111|1100 */ {0xffffffc,28}, |
| /* (128) |11111111|11111110|0110 */ {0xfffe6,20}, |
| /* (129) |11111111|11111111|010010 */ {0x3fffd2,22}, |
| /* (130) |11111111|11111110|0111 */ {0xfffe7,20}, |
| /* (131) |11111111|11111110|1000 */ {0xfffe8,20}, |
| /* (132) |11111111|11111111|010011 */ {0x3fffd3,22}, |
| /* (133) |11111111|11111111|010100 */ {0x3fffd4,22}, |
| /* (134) |11111111|11111111|010101 */ {0x3fffd5,22}, |
| /* (135) |11111111|11111111|1011001 */ {0x7fffd9,23}, |
| /* (136) |11111111|11111111|010110 */ {0x3fffd6,22}, |
| /* (137) |11111111|11111111|1011010 */ {0x7fffda,23}, |
| /* (138) |11111111|11111111|1011011 */ {0x7fffdb,23}, |
| /* (139) |11111111|11111111|1011100 */ {0x7fffdc,23}, |
| /* (140) |11111111|11111111|1011101 */ {0x7fffdd,23}, |
| /* (141) |11111111|11111111|1011110 */ {0x7fffde,23}, |
| /* (142) |11111111|11111111|11101011 */ {0xffffeb,24}, |
| /* (143) |11111111|11111111|1011111 */ {0x7fffdf,23}, |
| /* (144) |11111111|11111111|11101100 */ {0xffffec,24}, |
| /* (145) |11111111|11111111|11101101 */ {0xffffed,24}, |
| /* (146) |11111111|11111111|010111 */ {0x3fffd7,22}, |
| /* (147) |11111111|11111111|1100000 */ {0x7fffe0,23}, |
| /* (148) |11111111|11111111|11101110 */ {0xffffee,24}, |
| /* (149) |11111111|11111111|1100001 */ {0x7fffe1,23}, |
| /* (150) |11111111|11111111|1100010 */ {0x7fffe2,23}, |
| /* (151) |11111111|11111111|1100011 */ {0x7fffe3,23}, |
| /* (152) |11111111|11111111|1100100 */ {0x7fffe4,23}, |
| /* (153) |11111111|11111110|11100 */ {0x1fffdc,21}, |
| /* (154) |11111111|11111111|011000 */ {0x3fffd8,22}, |
| /* (155) |11111111|11111111|1100101 */ {0x7fffe5,23}, |
| /* (156) |11111111|11111111|011001 */ {0x3fffd9,22}, |
| /* (157) |11111111|11111111|1100110 */ {0x7fffe6,23}, |
| /* (158) |11111111|11111111|1100111 */ {0x7fffe7,23}, |
| /* (159) |11111111|11111111|11101111 */ {0xffffef,24}, |
| /* (160) |11111111|11111111|011010 */ {0x3fffda,22}, |
| /* (161) |11111111|11111110|11101 */ {0x1fffdd,21}, |
| /* (162) |11111111|11111110|1001 */ {0xfffe9,20}, |
| /* (163) |11111111|11111111|011011 */ {0x3fffdb,22}, |
| /* (164) |11111111|11111111|011100 */ {0x3fffdc,22}, |
| /* (165) |11111111|11111111|1101000 */ {0x7fffe8,23}, |
| /* (166) |11111111|11111111|1101001 */ {0x7fffe9,23}, |
| /* (167) |11111111|11111110|11110 */ {0x1fffde,21}, |
| /* (168) |11111111|11111111|1101010 */ {0x7fffea,23}, |
| /* (169) |11111111|11111111|011101 */ {0x3fffdd,22}, |
| /* (170) |11111111|11111111|011110 */ {0x3fffde,22}, |
| /* (171) |11111111|11111111|11110000 */ {0xfffff0,24}, |
| /* (172) |11111111|11111110|11111 */ {0x1fffdf,21}, |
| /* (173) |11111111|11111111|011111 */ {0x3fffdf,22}, |
| /* (174) |11111111|11111111|1101011 */ {0x7fffeb,23}, |
| /* (175) |11111111|11111111|1101100 */ {0x7fffec,23}, |
| /* (176) |11111111|11111111|00000 */ {0x1fffe0,21}, |
| /* (177) |11111111|11111111|00001 */ {0x1fffe1,21}, |
| /* (178) |11111111|11111111|100000 */ {0x3fffe0,22}, |
| /* (179) |11111111|11111111|00010 */ {0x1fffe2,21}, |
| /* (180) |11111111|11111111|1101101 */ {0x7fffed,23}, |
| /* (181) |11111111|11111111|100001 */ {0x3fffe1,22}, |
| /* (182) |11111111|11111111|1101110 */ {0x7fffee,23}, |
| /* (183) |11111111|11111111|1101111 */ {0x7fffef,23}, |
| /* (184) |11111111|11111110|1010 */ {0xfffea,20}, |
| /* (185) |11111111|11111111|100010 */ {0x3fffe2,22}, |
| /* (186) |11111111|11111111|100011 */ {0x3fffe3,22}, |
| /* (187) |11111111|11111111|100100 */ {0x3fffe4,22}, |
| /* (188) |11111111|11111111|1110000 */ {0x7ffff0,23}, |
| /* (189) |11111111|11111111|100101 */ {0x3fffe5,22}, |
| /* (190) |11111111|11111111|100110 */ {0x3fffe6,22}, |
| /* (191) |11111111|11111111|1110001 */ {0x7ffff1,23}, |
| /* (192) |11111111|11111111|11111000|00 */ {0x3ffffe0,26}, |
| /* (193) |11111111|11111111|11111000|01 */ {0x3ffffe1,26}, |
| /* (194) |11111111|11111110|1011 */ {0xfffeb,20}, |
| /* (195) |11111111|11111110|001 */ {0x7fff1,19}, |
| /* (196) |11111111|11111111|100111 */ {0x3fffe7,22}, |
| /* (197) |11111111|11111111|1110010 */ {0x7ffff2,23}, |
| /* (198) |11111111|11111111|101000 */ {0x3fffe8,22}, |
| /* (199) |11111111|11111111|11110110|0 */ {0x1ffffec,25}, |
| /* (200) |11111111|11111111|11111000|10 */ {0x3ffffe2,26}, |
| /* (201) |11111111|11111111|11111000|11 */ {0x3ffffe3,26}, |
| /* (202) |11111111|11111111|11111001|00 */ {0x3ffffe4,26}, |
| /* (203) |11111111|11111111|11111011|110 */ {0x7ffffde,27}, |
| /* (204) |11111111|11111111|11111011|111 */ {0x7ffffdf,27}, |
| /* (205) |11111111|11111111|11111001|01 */ {0x3ffffe5,26}, |
| /* (206) |11111111|11111111|11110001 */ {0xfffff1,24}, |
| /* (207) |11111111|11111111|11110110|1 */ {0x1ffffed,25}, |
| /* (208) |11111111|11111110|010 */ {0x7fff2,19}, |
| /* (209) |11111111|11111111|00011 */ {0x1fffe3,21}, |
| /* (210) |11111111|11111111|11111001|10 */ {0x3ffffe6,26}, |
| /* (211) |11111111|11111111|11111100|000 */ {0x7ffffe0,27}, |
| /* (212) |11111111|11111111|11111100|001 */ {0x7ffffe1,27}, |
| /* (213) |11111111|11111111|11111001|11 */ {0x3ffffe7,26}, |
| /* (214) |11111111|11111111|11111100|010 */ {0x7ffffe2,27}, |
| /* (215) |11111111|11111111|11110010 */ {0xfffff2,24}, |
| /* (216) |11111111|11111111|00100 */ {0x1fffe4,21}, |
| /* (217) |11111111|11111111|00101 */ {0x1fffe5,21}, |
| /* (218) |11111111|11111111|11111010|00 */ {0x3ffffe8,26}, |
| /* (219) |11111111|11111111|11111010|01 */ {0x3ffffe9,26}, |
| /* (220) |11111111|11111111|11111111|1101 */ {0xffffffd,28}, |
| /* (221) |11111111|11111111|11111100|011 */ {0x7ffffe3,27}, |
| /* (222) |11111111|11111111|11111100|100 */ {0x7ffffe4,27}, |
| /* (223) |11111111|11111111|11111100|101 */ {0x7ffffe5,27}, |
| /* (224) |11111111|11111110|1100 */ {0xfffec,20}, |
| /* (225) |11111111|11111111|11110011 */ {0xfffff3,24}, |
| /* (226) |11111111|11111110|1101 */ {0xfffed,20}, |
| /* (227) |11111111|11111111|00110 */ {0x1fffe6,21}, |
| /* (228) |11111111|11111111|101001 */ {0x3fffe9,22}, |
| /* (229) |11111111|11111111|00111 */ {0x1fffe7,21}, |
| /* (230) |11111111|11111111|01000 */ {0x1fffe8,21}, |
| /* (231) |11111111|11111111|1110011 */ {0x7ffff3,23}, |
| /* (232) |11111111|11111111|101010 */ {0x3fffea,22}, |
| /* (233) |11111111|11111111|101011 */ {0x3fffeb,22}, |
| /* (234) |11111111|11111111|11110111|0 */ {0x1ffffee,25}, |
| /* (235) |11111111|11111111|11110111|1 */ {0x1ffffef,25}, |
| /* (236) |11111111|11111111|11110100 */ {0xfffff4,24}, |
| /* (237) |11111111|11111111|11110101 */ {0xfffff5,24}, |
| /* (238) |11111111|11111111|11111010|10 */ {0x3ffffea,26}, |
| /* (239) |11111111|11111111|1110100 */ {0x7ffff4,23}, |
| /* (240) |11111111|11111111|11111010|11 */ {0x3ffffeb,26}, |
| /* (241) |11111111|11111111|11111100|110 */ {0x7ffffe6,27}, |
| /* (242) |11111111|11111111|11111011|00 */ {0x3ffffec,26}, |
| /* (243) |11111111|11111111|11111011|01 */ {0x3ffffed,26}, |
| /* (244) |11111111|11111111|11111100|111 */ {0x7ffffe7,27}, |
| /* (245) |11111111|11111111|11111101|000 */ {0x7ffffe8,27}, |
| /* (246) |11111111|11111111|11111101|001 */ {0x7ffffe9,27}, |
| /* (247) |11111111|11111111|11111101|010 */ {0x7ffffea,27}, |
| /* (248) |11111111|11111111|11111101|011 */ {0x7ffffeb,27}, |
| /* (249) |11111111|11111111|11111111|1110 */ {0xffffffe,28}, |
| /* (250) |11111111|11111111|11111101|100 */ {0x7ffffec,27}, |
| /* (251) |11111111|11111111|11111101|101 */ {0x7ffffed,27}, |
| /* (252) |11111111|11111111|11111101|110 */ {0x7ffffee,27}, |
| /* (253) |11111111|11111111|11111101|111 */ {0x7ffffef,27}, |
| /* (254) |11111111|11111111|11111110|000 */ {0x7fffff0,27}, |
| /* (255) |11111111|11111111|11111011|10 */ {0x3ffffee,26}, |
| /*EOS (256) |11111111|11111111|11111111|111111 */ {0x3fffffff,30}, |
| }; |
| |
| static final int[][] LCCODES = new int[CODES.length][]; |
| |
| // Huffman decode tree stored in a flattened char array for good |
| // locality of reference. |
| static final char[] tree; |
| static final char[] rowsym; |
| static final byte[] rowbits; |
| |
| // Build the Huffman lookup tree and LC TABLE |
| static |
| { |
| System.arraycopy(CODES,0,LCCODES,0,CODES.length); |
| for (int i='A';i<='Z';i++) |
| LCCODES[i]=LCCODES['a'+i-'A']; |
| |
| int r=0; |
| for (int i=0;i<CODES.length;i++) |
| r+=(CODES[i][1]+7)/8; |
| tree=new char[r*256]; |
| rowsym=new char[r]; |
| rowbits=new byte[r]; |
| |
| r=0; |
| for (int sym = 0; sym < CODES.length; sym++) |
| { |
| int code = CODES[sym][0]; |
| int len = CODES[sym][1]; |
| |
| int current = 0; |
| |
| while (len > 8) |
| { |
| len -= 8; |
| int i = ((code >>> len) & 0xFF); |
| |
| int t=current*256+i; |
| current = tree[t]; |
| if (current == 0) |
| { |
| tree[t] = (char)++r; |
| current=r; |
| } |
| } |
| |
| int terminal = ++r; |
| rowsym[r]=(char)sym; |
| int b = len & 0x07; |
| int terminalBits = b == 0?8:b; |
| |
| rowbits[r]=(byte)terminalBits; |
| int shift = 8 - len; |
| int start = current*256 + ((code << shift) & 0xFF); |
| int end = start + (1<<shift); |
| for (int i = start; i < end; i++) |
| tree[i]=(char)terminal; |
| } |
| } |
| |
| public static String decode(ByteBuffer buffer) |
| { |
| return decode(buffer,buffer.remaining()); |
| } |
| |
| public static String decode(ByteBuffer buffer,int length) |
| { |
| StringBuilder out = new StringBuilder(length*2); |
| int node = 0; |
| int current = 0; |
| int bits = 0; |
| |
| byte[] array = buffer.array(); |
| int position=buffer.position(); |
| int start=buffer.arrayOffset()+position; |
| int end=start+length; |
| buffer.position(position+length); |
| |
| for (int i=start; i<end; i++) |
| { |
| int b = array[i]&0xFF; |
| current = (current << 8) | b; |
| bits += 8; |
| while (bits >= 8) |
| { |
| int c = (current >>> (bits - 8)) & 0xFF; |
| node = tree[node*256+c]; |
| if (rowbits[node]!=0) |
| { |
| // terminal node |
| out.append(rowsym[node]); |
| bits -= rowbits[node]; |
| node = 0; |
| } |
| else |
| { |
| // non-terminal node |
| bits -= 8; |
| } |
| } |
| } |
| |
| while (bits > 0) |
| { |
| int c = (current << (8 - bits)) & 0xFF; |
| node = tree[node*256+c]; |
| if (rowbits[node]==0 || rowbits[node] > bits) |
| break; |
| |
| if (rowbits[node]==0) |
| throw new IllegalStateException(); |
| |
| out.append(rowsym[node]); |
| bits -= rowbits[node]; |
| node = 0; |
| } |
| |
| return out.toString(); |
| } |
| |
| public static int octetsNeeded(String s) |
| { |
| return octetsNeeded(CODES,s); |
| } |
| |
| public static void encode(ByteBuffer buffer,String s) |
| { |
| encode(CODES,buffer,s); |
| } |
| |
| public static int octetsNeededLC(String s) |
| { |
| return octetsNeeded(LCCODES,s); |
| } |
| |
| public static void encodeLC(ByteBuffer buffer, String s) |
| { |
| encode(LCCODES,buffer,s); |
| } |
| |
| private static int octetsNeeded(final int[][] table,String s) |
| { |
| int needed=0; |
| int len = s.length(); |
| for (int i=0;i<len;i++) |
| { |
| char c=s.charAt(i); |
| if (c>=128 || c<' ') |
| throw new IllegalArgumentException(); |
| needed += table[c][1]; |
| } |
| |
| return (needed+7) / 8; |
| } |
| |
| private static void encode(final int[][] table,ByteBuffer buffer,String s) |
| { |
| long current = 0; |
| int n = 0; |
| |
| byte[] array = buffer.array(); |
| int p=buffer.arrayOffset()+buffer.position(); |
| |
| int len = s.length(); |
| for (int i=0;i<len;i++) |
| { |
| char c=s.charAt(i); |
| if (c>=128 || c<' ') |
| throw new IllegalArgumentException(); |
| int code = table[c][0]; |
| int bits = table[c][1]; |
| |
| current <<= bits; |
| current |= code; |
| n += bits; |
| |
| while (n >= 8) |
| { |
| n -= 8; |
| array[p++]=(byte)(current >> n); |
| } |
| } |
| |
| if (n > 0) |
| { |
| current <<= (8 - n); |
| current |= (0xFF >>> n); |
| array[p++]=(byte)current; |
| } |
| |
| buffer.position(p-buffer.arrayOffset()); |
| } |
| |
| } |
