All Downloads are FREE. Search and download functionalities are using the official Maven repository.

org.apache.coyote.http2.HPackHuffman Maven / Gradle / Ivy

There is a newer version: 11.0.0-M26
Show newest version
/*
 *  Licensed to the Apache Software Foundation (ASF) under one or more
 *  contributor license agreements.  See the NOTICE file distributed with
 *  this work for additional information regarding copyright ownership.
 *  The ASF licenses this file to You under the Apache License, Version 2.0
 *  (the "License"); you may not use this file except in compliance with
 *  the License.  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */
package org.apache.coyote.http2;

import java.nio.ByteBuffer;
import java.util.Arrays;
import java.util.HashSet;
import java.util.Set;

import org.apache.tomcat.util.res.StringManager;

public class HPackHuffman {

    protected static final StringManager sm = StringManager.getManager(HPackHuffman.class);

    private static final HuffmanCode[] HUFFMAN_CODES;

    /**
     * array based tree representation of a huffman code.
     * 

* the high two bytes corresponds to the tree node if the bit is set, and the low two bytes for if it is clear * if the high bit is set it is a terminal node, otherwise it contains the next node position. */ private static final int[] DECODING_TABLE; private static final int LOW_TERMINAL_BIT = (0b10000000) << 8; private static final int HIGH_TERMINAL_BIT = (0b10000000) << 24; private static final int LOW_MASK = 0b0111111111111111; static { HuffmanCode[] codes = new HuffmanCode[257]; codes[0] = new HuffmanCode(0x1ff8, 13); codes[1] = new HuffmanCode(0x7fffd8, 23); codes[2] = new HuffmanCode(0xfffffe2, 28); codes[3] = new HuffmanCode(0xfffffe3, 28); codes[4] = new HuffmanCode(0xfffffe4, 28); codes[5] = new HuffmanCode(0xfffffe5, 28); codes[6] = new HuffmanCode(0xfffffe6, 28); codes[7] = new HuffmanCode(0xfffffe7, 28); codes[8] = new HuffmanCode(0xfffffe8, 28); codes[9] = new HuffmanCode(0xffffea, 24); codes[10] = new HuffmanCode(0x3ffffffc, 30); codes[11] = new HuffmanCode(0xfffffe9, 28); codes[12] = new HuffmanCode(0xfffffea, 28); codes[13] = new HuffmanCode(0x3ffffffd, 30); codes[14] = new HuffmanCode(0xfffffeb, 28); codes[15] = new HuffmanCode(0xfffffec, 28); codes[16] = new HuffmanCode(0xfffffed, 28); codes[17] = new HuffmanCode(0xfffffee, 28); codes[18] = new HuffmanCode(0xfffffef, 28); codes[19] = new HuffmanCode(0xffffff0, 28); codes[20] = new HuffmanCode(0xffffff1, 28); codes[21] = new HuffmanCode(0xffffff2, 28); codes[22] = new HuffmanCode(0x3ffffffe, 30); codes[23] = new HuffmanCode(0xffffff3, 28); codes[24] = new HuffmanCode(0xffffff4, 28); codes[25] = new HuffmanCode(0xffffff5, 28); codes[26] = new HuffmanCode(0xffffff6, 28); codes[27] = new HuffmanCode(0xffffff7, 28); codes[28] = new HuffmanCode(0xffffff8, 28); codes[29] = new HuffmanCode(0xffffff9, 28); codes[30] = new HuffmanCode(0xffffffa, 28); codes[31] = new HuffmanCode(0xffffffb, 28); codes[32] = new HuffmanCode(0x14, 6); codes[33] = new HuffmanCode(0x3f8, 10); codes[34] = new HuffmanCode(0x3f9, 10); codes[35] = new HuffmanCode(0xffa, 12); codes[36] = new HuffmanCode(0x1ff9, 13); codes[37] = new HuffmanCode(0x15, 6); codes[38] = new HuffmanCode(0xf8, 8); codes[39] = new HuffmanCode(0x7fa, 11); codes[40] = new HuffmanCode(0x3fa, 10); codes[41] = new HuffmanCode(0x3fb, 10); codes[42] = new HuffmanCode(0xf9, 8); codes[43] = new HuffmanCode(0x7fb, 11); codes[44] = new HuffmanCode(0xfa, 8); codes[45] = new HuffmanCode(0x16, 6); codes[46] = new HuffmanCode(0x17, 6); codes[47] = new HuffmanCode(0x18, 6); codes[48] = new HuffmanCode(0x0, 5); codes[49] = new HuffmanCode(0x1, 5); codes[50] = new HuffmanCode(0x2, 5); codes[51] = new HuffmanCode(0x19, 6); codes[52] = new HuffmanCode(0x1a, 6); codes[53] = new HuffmanCode(0x1b, 6); codes[54] = new HuffmanCode(0x1c, 6); codes[55] = new HuffmanCode(0x1d, 6); codes[56] = new HuffmanCode(0x1e, 6); codes[57] = new HuffmanCode(0x1f, 6); codes[58] = new HuffmanCode(0x5c, 7); codes[59] = new HuffmanCode(0xfb, 8); codes[60] = new HuffmanCode(0x7ffc, 15); codes[61] = new HuffmanCode(0x20, 6); codes[62] = new HuffmanCode(0xffb, 12); codes[63] = new HuffmanCode(0x3fc, 10); codes[64] = new HuffmanCode(0x1ffa, 13); codes[65] = new HuffmanCode(0x21, 6); codes[66] = new HuffmanCode(0x5d, 7); codes[67] = new HuffmanCode(0x5e, 7); codes[68] = new HuffmanCode(0x5f, 7); codes[69] = new HuffmanCode(0x60, 7); codes[70] = new HuffmanCode(0x61, 7); codes[71] = new HuffmanCode(0x62, 7); codes[72] = new HuffmanCode(0x63, 7); codes[73] = new HuffmanCode(0x64, 7); codes[74] = new HuffmanCode(0x65, 7); codes[75] = new HuffmanCode(0x66, 7); codes[76] = new HuffmanCode(0x67, 7); codes[77] = new HuffmanCode(0x68, 7); codes[78] = new HuffmanCode(0x69, 7); codes[79] = new HuffmanCode(0x6a, 7); codes[80] = new HuffmanCode(0x6b, 7); codes[81] = new HuffmanCode(0x6c, 7); codes[82] = new HuffmanCode(0x6d, 7); codes[83] = new HuffmanCode(0x6e, 7); codes[84] = new HuffmanCode(0x6f, 7); codes[85] = new HuffmanCode(0x70, 7); codes[86] = new HuffmanCode(0x71, 7); codes[87] = new HuffmanCode(0x72, 7); codes[88] = new HuffmanCode(0xfc, 8); codes[89] = new HuffmanCode(0x73, 7); codes[90] = new HuffmanCode(0xfd, 8); codes[91] = new HuffmanCode(0x1ffb, 13); codes[92] = new HuffmanCode(0x7fff0, 19); codes[93] = new HuffmanCode(0x1ffc, 13); codes[94] = new HuffmanCode(0x3ffc, 14); codes[95] = new HuffmanCode(0x22, 6); codes[96] = new HuffmanCode(0x7ffd, 15); codes[97] = new HuffmanCode(0x3, 5); codes[98] = new HuffmanCode(0x23, 6); codes[99] = new HuffmanCode(0x4, 5); codes[100] = new HuffmanCode(0x24, 6); codes[101] = new HuffmanCode(0x5, 5); codes[102] = new HuffmanCode(0x25, 6); codes[103] = new HuffmanCode(0x26, 6); codes[104] = new HuffmanCode(0x27, 6); codes[105] = new HuffmanCode(0x6, 5); codes[106] = new HuffmanCode(0x74, 7); codes[107] = new HuffmanCode(0x75, 7); codes[108] = new HuffmanCode(0x28, 6); codes[109] = new HuffmanCode(0x29, 6); codes[110] = new HuffmanCode(0x2a, 6); codes[111] = new HuffmanCode(0x7, 5); codes[112] = new HuffmanCode(0x2b, 6); codes[113] = new HuffmanCode(0x76, 7); codes[114] = new HuffmanCode(0x2c, 6); codes[115] = new HuffmanCode(0x8, 5); codes[116] = new HuffmanCode(0x9, 5); codes[117] = new HuffmanCode(0x2d, 6); codes[118] = new HuffmanCode(0x77, 7); codes[119] = new HuffmanCode(0x78, 7); codes[120] = new HuffmanCode(0x79, 7); codes[121] = new HuffmanCode(0x7a, 7); codes[122] = new HuffmanCode(0x7b, 7); codes[123] = new HuffmanCode(0x7ffe, 15); codes[124] = new HuffmanCode(0x7fc, 11); codes[125] = new HuffmanCode(0x3ffd, 14); codes[126] = new HuffmanCode(0x1ffd, 13); codes[127] = new HuffmanCode(0xffffffc, 28); codes[128] = new HuffmanCode(0xfffe6, 20); codes[129] = new HuffmanCode(0x3fffd2, 22); codes[130] = new HuffmanCode(0xfffe7, 20); codes[131] = new HuffmanCode(0xfffe8, 20); codes[132] = new HuffmanCode(0x3fffd3, 22); codes[133] = new HuffmanCode(0x3fffd4, 22); codes[134] = new HuffmanCode(0x3fffd5, 22); codes[135] = new HuffmanCode(0x7fffd9, 23); codes[136] = new HuffmanCode(0x3fffd6, 22); codes[137] = new HuffmanCode(0x7fffda, 23); codes[138] = new HuffmanCode(0x7fffdb, 23); codes[139] = new HuffmanCode(0x7fffdc, 23); codes[140] = new HuffmanCode(0x7fffdd, 23); codes[141] = new HuffmanCode(0x7fffde, 23); codes[142] = new HuffmanCode(0xffffeb, 24); codes[143] = new HuffmanCode(0x7fffdf, 23); codes[144] = new HuffmanCode(0xffffec, 24); codes[145] = new HuffmanCode(0xffffed, 24); codes[146] = new HuffmanCode(0x3fffd7, 22); codes[147] = new HuffmanCode(0x7fffe0, 23); codes[148] = new HuffmanCode(0xffffee, 24); codes[149] = new HuffmanCode(0x7fffe1, 23); codes[150] = new HuffmanCode(0x7fffe2, 23); codes[151] = new HuffmanCode(0x7fffe3, 23); codes[152] = new HuffmanCode(0x7fffe4, 23); codes[153] = new HuffmanCode(0x1fffdc, 21); codes[154] = new HuffmanCode(0x3fffd8, 22); codes[155] = new HuffmanCode(0x7fffe5, 23); codes[156] = new HuffmanCode(0x3fffd9, 22); codes[157] = new HuffmanCode(0x7fffe6, 23); codes[158] = new HuffmanCode(0x7fffe7, 23); codes[159] = new HuffmanCode(0xffffef, 24); codes[160] = new HuffmanCode(0x3fffda, 22); codes[161] = new HuffmanCode(0x1fffdd, 21); codes[162] = new HuffmanCode(0xfffe9, 20); codes[163] = new HuffmanCode(0x3fffdb, 22); codes[164] = new HuffmanCode(0x3fffdc, 22); codes[165] = new HuffmanCode(0x7fffe8, 23); codes[166] = new HuffmanCode(0x7fffe9, 23); codes[167] = new HuffmanCode(0x1fffde, 21); codes[168] = new HuffmanCode(0x7fffea, 23); codes[169] = new HuffmanCode(0x3fffdd, 22); codes[170] = new HuffmanCode(0x3fffde, 22); codes[171] = new HuffmanCode(0xfffff0, 24); codes[172] = new HuffmanCode(0x1fffdf, 21); codes[173] = new HuffmanCode(0x3fffdf, 22); codes[174] = new HuffmanCode(0x7fffeb, 23); codes[175] = new HuffmanCode(0x7fffec, 23); codes[176] = new HuffmanCode(0x1fffe0, 21); codes[177] = new HuffmanCode(0x1fffe1, 21); codes[178] = new HuffmanCode(0x3fffe0, 22); codes[179] = new HuffmanCode(0x1fffe2, 21); codes[180] = new HuffmanCode(0x7fffed, 23); codes[181] = new HuffmanCode(0x3fffe1, 22); codes[182] = new HuffmanCode(0x7fffee, 23); codes[183] = new HuffmanCode(0x7fffef, 23); codes[184] = new HuffmanCode(0xfffea, 20); codes[185] = new HuffmanCode(0x3fffe2, 22); codes[186] = new HuffmanCode(0x3fffe3, 22); codes[187] = new HuffmanCode(0x3fffe4, 22); codes[188] = new HuffmanCode(0x7ffff0, 23); codes[189] = new HuffmanCode(0x3fffe5, 22); codes[190] = new HuffmanCode(0x3fffe6, 22); codes[191] = new HuffmanCode(0x7ffff1, 23); codes[192] = new HuffmanCode(0x3ffffe0, 26); codes[193] = new HuffmanCode(0x3ffffe1, 26); codes[194] = new HuffmanCode(0xfffeb, 20); codes[195] = new HuffmanCode(0x7fff1, 19); codes[196] = new HuffmanCode(0x3fffe7, 22); codes[197] = new HuffmanCode(0x7ffff2, 23); codes[198] = new HuffmanCode(0x3fffe8, 22); codes[199] = new HuffmanCode(0x1ffffec, 25); codes[200] = new HuffmanCode(0x3ffffe2, 26); codes[201] = new HuffmanCode(0x3ffffe3, 26); codes[202] = new HuffmanCode(0x3ffffe4, 26); codes[203] = new HuffmanCode(0x7ffffde, 27); codes[204] = new HuffmanCode(0x7ffffdf, 27); codes[205] = new HuffmanCode(0x3ffffe5, 26); codes[206] = new HuffmanCode(0xfffff1, 24); codes[207] = new HuffmanCode(0x1ffffed, 25); codes[208] = new HuffmanCode(0x7fff2, 19); codes[209] = new HuffmanCode(0x1fffe3, 21); codes[210] = new HuffmanCode(0x3ffffe6, 26); codes[211] = new HuffmanCode(0x7ffffe0, 27); codes[212] = new HuffmanCode(0x7ffffe1, 27); codes[213] = new HuffmanCode(0x3ffffe7, 26); codes[214] = new HuffmanCode(0x7ffffe2, 27); codes[215] = new HuffmanCode(0xfffff2, 24); codes[216] = new HuffmanCode(0x1fffe4, 21); codes[217] = new HuffmanCode(0x1fffe5, 21); codes[218] = new HuffmanCode(0x3ffffe8, 26); codes[219] = new HuffmanCode(0x3ffffe9, 26); codes[220] = new HuffmanCode(0xffffffd, 28); codes[221] = new HuffmanCode(0x7ffffe3, 27); codes[222] = new HuffmanCode(0x7ffffe4, 27); codes[223] = new HuffmanCode(0x7ffffe5, 27); codes[224] = new HuffmanCode(0xfffec, 20); codes[225] = new HuffmanCode(0xfffff3, 24); codes[226] = new HuffmanCode(0xfffed, 20); codes[227] = new HuffmanCode(0x1fffe6, 21); codes[228] = new HuffmanCode(0x3fffe9, 22); codes[229] = new HuffmanCode(0x1fffe7, 21); codes[230] = new HuffmanCode(0x1fffe8, 21); codes[231] = new HuffmanCode(0x7ffff3, 23); codes[232] = new HuffmanCode(0x3fffea, 22); codes[233] = new HuffmanCode(0x3fffeb, 22); codes[234] = new HuffmanCode(0x1ffffee, 25); codes[235] = new HuffmanCode(0x1ffffef, 25); codes[236] = new HuffmanCode(0xfffff4, 24); codes[237] = new HuffmanCode(0xfffff5, 24); codes[238] = new HuffmanCode(0x3ffffea, 26); codes[239] = new HuffmanCode(0x7ffff4, 23); codes[240] = new HuffmanCode(0x3ffffeb, 26); codes[241] = new HuffmanCode(0x7ffffe6, 27); codes[242] = new HuffmanCode(0x3ffffec, 26); codes[243] = new HuffmanCode(0x3ffffed, 26); codes[244] = new HuffmanCode(0x7ffffe7, 27); codes[245] = new HuffmanCode(0x7ffffe8, 27); codes[246] = new HuffmanCode(0x7ffffe9, 27); codes[247] = new HuffmanCode(0x7ffffea, 27); codes[248] = new HuffmanCode(0x7ffffeb, 27); codes[249] = new HuffmanCode(0xffffffe, 28); codes[250] = new HuffmanCode(0x7ffffec, 27); codes[251] = new HuffmanCode(0x7ffffed, 27); codes[252] = new HuffmanCode(0x7ffffee, 27); codes[253] = new HuffmanCode(0x7ffffef, 27); codes[254] = new HuffmanCode(0x7fffff0, 27); codes[255] = new HuffmanCode(0x3ffffee, 26); codes[256] = new HuffmanCode(0x3fffffff, 30); HUFFMAN_CODES = codes; //lengths determined by experimentation, just set it to something large then see how large it actually ends up int[] codingTree = new int[256]; //the current position in the tree int pos = 0; int allocated = 1; //the next position to allocate to //map of the current state at a given position //only used while building the tree HuffmanCode[] currentCode = new HuffmanCode[256]; currentCode[0] = new HuffmanCode(0, 0); final Set allCodes = new HashSet<>(Arrays.asList(HUFFMAN_CODES)); while (!allCodes.isEmpty()) { int length = currentCode[pos].length; int code = currentCode[pos].value; int newLength = length + 1; HuffmanCode high = new HuffmanCode(code << 1 | 1, newLength); HuffmanCode low = new HuffmanCode(code << 1, newLength); int newVal = 0; boolean highTerminal = allCodes.remove(high); if (highTerminal) { //bah, linear search int i = 0; for (i = 0; i < codes.length; ++i) { if (codes[i].equals(high)) { break; } } newVal = LOW_TERMINAL_BIT | i; } else { int highPos = allocated++; currentCode[highPos] = high; newVal = highPos; } newVal <<= 16; boolean lowTerminal = allCodes.remove(low); if (lowTerminal) { //bah, linear search int i = 0; for (i = 0; i < codes.length; ++i) { if (codes[i].equals(low)) { break; } } newVal |= LOW_TERMINAL_BIT | i; } else { int lowPos = allocated++; currentCode[lowPos] = low; newVal |= lowPos; } codingTree[pos] = newVal; pos++; } DECODING_TABLE = codingTree; } /** * Decodes a huffman encoded string into the target StringBuilder. There * must be enough space left in the buffer for this method to succeed. * * @param data The byte buffer * @param length The length of data from the buffer to decode * @param target The target for the decompressed data * * @throws HpackException If the Huffman encoded value in HPACK headers did * not end with EOS padding */ public static void decode(ByteBuffer data, int length, StringBuilder target) throws HpackException { assert data.remaining() >= length; int treePos = 0; boolean eosBits = true; int eosBitCount = 0; for (int i = 0; i < length; ++i) { byte b = data.get(); int bitPos = 7; while (bitPos >= 0) { int val = DECODING_TABLE[treePos]; if (((1 << bitPos) & b) == 0) { //bit not set, we want the lower part of the tree if ((val & LOW_TERMINAL_BIT) == 0) { treePos = val & LOW_MASK; eosBits = false; eosBitCount = 0; } else { target.append((char) (val & LOW_MASK)); treePos = 0; eosBits = true; } } else { if (eosBits) { eosBitCount++; } //bit not set, we want the lower part of the tree if ((val & HIGH_TERMINAL_BIT) == 0) { treePos = (val >> 16) & LOW_MASK; } else { if (eosBitCount != 0) { // This must be the EOS symbol which MUST be treated // as an error throw new HpackException(sm.getString("hpackhuffman.stringLiteralEOS")); } target.append((char) ((val >> 16) & LOW_MASK)); treePos = 0; eosBits = true; } } bitPos--; } } if (eosBitCount > 7) { throw new HpackException(sm.getString( "hpackhuffman.stringLiteralTooMuchPadding")); } if (!eosBits) { throw new HpackException(sm.getString( "hpackhuffman.huffmanEncodedHpackValueDidNotEndWithEOS")); } } /** * Encodes the given string into the buffer. If there is not enough space in * the buffer, or the encoded version is bigger than the original it will * return false and not modify the buffers position. * * @param buffer The buffer to encode into * @param toEncode The string to encode * @param forceLowercase If the string should be encoded in lower case * @return true if encoding succeeded */ public static boolean encode(ByteBuffer buffer, String toEncode, boolean forceLowercase) { if (buffer.remaining() <= toEncode.length()) { return false; } int start = buffer.position(); //this sucks, but we need to put the length first //and we don't really have any option but to calculate it in advance to make sure we have left enough room //so we end up iterating twice int length = 0; for (int i = 0; i < toEncode.length(); ++i) { char c = toEncode.charAt(i); if (c > 255) { throw new IllegalArgumentException(sm.getString("hpack.invalidCharacter", Character.toString(c), Integer.valueOf(c))); } if(forceLowercase) { c = Hpack.toLower(c); } HuffmanCode code = HUFFMAN_CODES[c]; length += code.length; } int byteLength = length / 8 + (length % 8 == 0 ? 0 : 1); buffer.put((byte) (1 << 7)); Hpack.encodeInteger(buffer, byteLength, 7); int bytePos = 0; byte currentBufferByte = 0; for (int i = 0; i < toEncode.length(); ++i) { char c = toEncode.charAt(i); if(forceLowercase) { c = Hpack.toLower(c); } HuffmanCode code = HUFFMAN_CODES[c]; if (code.length + bytePos <= 8) { //it fits in the current byte currentBufferByte |= ((code.value & 0xFF) << 8 - (code.length + bytePos)); bytePos += code.length; } else { //it does not fit, it may need up to 4 bytes int val = code.value; int rem = code.length; while (rem > 0) { if (!buffer.hasRemaining()) { buffer.position(start); return false; } int remainingInByte = 8 - bytePos; if (rem > remainingInByte) { currentBufferByte |= (val >> (rem - remainingInByte)); } else { currentBufferByte |= (val << (remainingInByte - rem)); } if (rem > remainingInByte) { buffer.put(currentBufferByte); currentBufferByte = 0; bytePos = 0; } else { bytePos = rem; } rem -= remainingInByte; } } if (bytePos == 8) { if (!buffer.hasRemaining()) { buffer.position(start); return false; } buffer.put(currentBufferByte); currentBufferByte = 0; bytePos = 0; } if (buffer.position() - start > toEncode.length()) { //the encoded version is longer than the original //just return false buffer.position(start); return false; } } if (bytePos > 0) { //add the EOS bytes if we have not finished on a single byte if (!buffer.hasRemaining()) { buffer.position(start); return false; } buffer.put((byte) (currentBufferByte | ((0xFF) >> bytePos))); } return true; } protected static class HuffmanCode { /** * The value of the least significant bits of the code */ int value; /** * length of the code, in bits */ int length; public HuffmanCode(int value, int length) { this.value = value; this.length = length; } public int getValue() { return value; } public int getLength() { return length; } @Override public boolean equals(Object o) { if (this == o) { return true; } if (o == null || getClass() != o.getClass()) { return false; } HuffmanCode that = (HuffmanCode) o; if (length != that.length) { return false; } if (value != that.value) { return false; } return true; } @Override public int hashCode() { int result = value; result = 31 * result + length; return result; } @Override public String toString() { return "HuffmanCode{" + "value=" + value + ", length=" + length + '}'; } } }





© 2015 - 2024 Weber Informatics LLC | Privacy Policy