//
// ========================================================================
// Copyright (c) 1995-2017 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());
}
}