| /* |
| * Copyright (c) 2014, 2018, Oracle and/or its affiliates. All rights reserved. |
| * DO NOT ALTER OR REMOVE COPYRIGHT NOTICES OR THIS FILE HEADER. |
| * |
| * This code is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License version 2 only, as |
| * published by the Free Software Foundation. Oracle designates this |
| * particular file as subject to the "Classpath" exception as provided |
| * by Oracle in the LICENSE file that accompanied this code. |
| * |
| * This code is distributed in the hope that it will be useful, but WITHOUT |
| * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or |
| * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * version 2 for more details (a copy is included in the LICENSE file that |
| * accompanied this code). |
| * |
| * You should have received a copy of the GNU General Public License version |
| * 2 along with this work; if not, write to the Free Software Foundation, |
| * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301 USA. |
| * |
| * Please contact Oracle, 500 Oracle Parkway, Redwood Shores, CA 94065 USA |
| * or visit www.oracle.com if you need additional information or have any |
| * questions. |
| */ |
| package jdk.internal.net.http.hpack; |
| |
| import java.io.IOException; |
| import java.nio.ByteBuffer; |
| |
| import static java.lang.String.format; |
| |
| /** |
| * Huffman coding table. |
| * |
| * <p> Instances of this class are safe for use by multiple threads. |
| * |
| * @since 9 |
| */ |
| public final class NaiveHuffman { |
| |
| // TODO: check if reset is done in both reader and writer |
| |
| static final class Reader implements Huffman.Reader { |
| |
| private Node curr; // position in the trie |
| private int len; // length of the path from the root to 'curr' |
| private int p; // byte probe |
| |
| { |
| reset(); |
| } |
| |
| @Override |
| public void read(ByteBuffer source, |
| Appendable destination, |
| boolean isLast) throws IOException { |
| read(source, destination, true, isLast); |
| } |
| |
| // Takes 'isLast' rather than returns whether the reading is done or |
| // not, for more informative exceptions. |
| void read(ByteBuffer source, |
| Appendable destination, |
| boolean reportEOS, /* reportEOS is exposed for tests */ |
| boolean isLast) throws IOException { |
| Node c = curr; |
| int l = len; |
| /* |
| Since ByteBuffer is itself stateful, its position is |
| remembered here NOT as a part of Reader's state, |
| but to set it back in the case of a failure |
| */ |
| int pos = source.position(); |
| |
| while (source.hasRemaining()) { |
| int d = source.get(); |
| for (; p != 0; p >>= 1) { |
| c = c.getChild(p & d); |
| l++; |
| if (c.isLeaf()) { |
| if (reportEOS && c.isEOSPath) { |
| throw new IOException("Encountered EOS"); |
| } |
| char ch; |
| try { |
| ch = c.getChar(); |
| } catch (IllegalStateException e) { |
| source.position(pos); // do we need this? |
| throw new IOException(e); |
| } |
| try { |
| destination.append(ch); |
| } catch (IOException e) { |
| source.position(pos); // do we need this? |
| throw e; |
| } |
| c = INSTANCE.root; |
| l = 0; |
| } |
| curr = c; |
| len = l; |
| } |
| resetProbe(); |
| pos++; |
| } |
| if (!isLast) { |
| return; // it's too early to jump to any conclusions, let's wait |
| } |
| if (c.isLeaf()) { |
| return; // it's perfectly ok, no extra padding bits |
| } |
| if (c.isEOSPath && len <= 7) { |
| return; // it's ok, some extra padding bits |
| } |
| if (c.isEOSPath) { |
| throw new IOException( |
| "Padding is too long (len=" + len + ") " + |
| "or unexpected end of data"); |
| } |
| throw new IOException( |
| "Not a EOS prefix padding or unexpected end of data"); |
| } |
| |
| @Override |
| public void reset() { |
| curr = INSTANCE.root; |
| len = 0; |
| resetProbe(); |
| } |
| |
| private void resetProbe() { |
| p = 0x80; |
| } |
| } |
| |
| static final class Writer implements Huffman.Writer { |
| |
| private int pos; // position in 'source' |
| private int avail = 8; // number of least significant bits available in 'curr' |
| private int curr; // next byte to put to the destination |
| private int rem; // number of least significant bits in 'code' yet to be processed |
| private int code; // current code being written |
| |
| private CharSequence source; |
| private int end; |
| |
| @Override |
| public Writer from(CharSequence input, int start, int end) { |
| if (start < 0 || end < 0 || end > input.length() || start > end) { |
| throw new IndexOutOfBoundsException( |
| String.format("input.length()=%s, start=%s, end=%s", |
| input.length(), start, end)); |
| } |
| pos = start; |
| this.end = end; |
| this.source = input; |
| return this; |
| } |
| |
| @Override |
| public boolean write(ByteBuffer destination) { |
| for (; pos < end; pos++) { |
| if (rem == 0) { |
| Code desc = INSTANCE.codeOf(source.charAt(pos)); |
| rem = desc.length; |
| code = desc.code; |
| } |
| while (rem > 0) { |
| if (rem < avail) { |
| curr |= (code << (avail - rem)); |
| avail -= rem; |
| rem = 0; |
| } else { |
| int c = (curr | (code >>> (rem - avail))); |
| if (destination.hasRemaining()) { |
| destination.put((byte) c); |
| } else { |
| return false; |
| } |
| curr = c; |
| code <<= (32 - rem + avail); // throw written bits off the cliff (is this Sparta?) |
| code >>>= (32 - rem + avail); // return to the position |
| rem -= avail; |
| curr = 0; |
| avail = 8; |
| } |
| } |
| } |
| |
| if (avail < 8) { // have to pad |
| if (destination.hasRemaining()) { |
| destination.put((byte) (curr | (INSTANCE.EOS.code >>> (INSTANCE.EOS.length - avail)))); |
| avail = 8; |
| } else { |
| return false; |
| } |
| } |
| |
| return true; |
| } |
| |
| @Override |
| public Writer reset() { |
| source = null; |
| end = -1; |
| pos = -1; |
| avail = 8; |
| curr = 0; |
| code = 0; |
| return this; |
| } |
| |
| @Override |
| public int lengthOf(CharSequence value, int start, int end) { |
| return INSTANCE.lengthOf(value, start, end); |
| } |
| } |
| |
| /** |
| * Shared instance. |
| */ |
| public static final NaiveHuffman INSTANCE = new NaiveHuffman(); |
| |
| private final Code EOS = new Code(0x3fffffff, 30); |
| private final Code[] codes = new Code[257]; |
| private final Node root = new Node() { |
| @Override |
| public String toString() { return "root"; } |
| }; |
| |
| // TODO: consider builder and immutable trie |
| private NaiveHuffman() { |
| // @formatter:off |
| addChar(0, 0x1ff8, 13); |
| addChar(1, 0x7fffd8, 23); |
| addChar(2, 0xfffffe2, 28); |
| addChar(3, 0xfffffe3, 28); |
| addChar(4, 0xfffffe4, 28); |
| addChar(5, 0xfffffe5, 28); |
| addChar(6, 0xfffffe6, 28); |
| addChar(7, 0xfffffe7, 28); |
| addChar(8, 0xfffffe8, 28); |
| addChar(9, 0xffffea, 24); |
| addChar(10, 0x3ffffffc, 30); |
| addChar(11, 0xfffffe9, 28); |
| addChar(12, 0xfffffea, 28); |
| addChar(13, 0x3ffffffd, 30); |
| addChar(14, 0xfffffeb, 28); |
| addChar(15, 0xfffffec, 28); |
| addChar(16, 0xfffffed, 28); |
| addChar(17, 0xfffffee, 28); |
| addChar(18, 0xfffffef, 28); |
| addChar(19, 0xffffff0, 28); |
| addChar(20, 0xffffff1, 28); |
| addChar(21, 0xffffff2, 28); |
| addChar(22, 0x3ffffffe, 30); |
| addChar(23, 0xffffff3, 28); |
| addChar(24, 0xffffff4, 28); |
| addChar(25, 0xffffff5, 28); |
| addChar(26, 0xffffff6, 28); |
| addChar(27, 0xffffff7, 28); |
| addChar(28, 0xffffff8, 28); |
| addChar(29, 0xffffff9, 28); |
| addChar(30, 0xffffffa, 28); |
| addChar(31, 0xffffffb, 28); |
| addChar(32, 0x14, 6); |
| addChar(33, 0x3f8, 10); |
| addChar(34, 0x3f9, 10); |
| addChar(35, 0xffa, 12); |
| addChar(36, 0x1ff9, 13); |
| addChar(37, 0x15, 6); |
| addChar(38, 0xf8, 8); |
| addChar(39, 0x7fa, 11); |
| addChar(40, 0x3fa, 10); |
| addChar(41, 0x3fb, 10); |
| addChar(42, 0xf9, 8); |
| addChar(43, 0x7fb, 11); |
| addChar(44, 0xfa, 8); |
| addChar(45, 0x16, 6); |
| addChar(46, 0x17, 6); |
| addChar(47, 0x18, 6); |
| addChar(48, 0x0, 5); |
| addChar(49, 0x1, 5); |
| addChar(50, 0x2, 5); |
| addChar(51, 0x19, 6); |
| addChar(52, 0x1a, 6); |
| addChar(53, 0x1b, 6); |
| addChar(54, 0x1c, 6); |
| addChar(55, 0x1d, 6); |
| addChar(56, 0x1e, 6); |
| addChar(57, 0x1f, 6); |
| addChar(58, 0x5c, 7); |
| addChar(59, 0xfb, 8); |
| addChar(60, 0x7ffc, 15); |
| addChar(61, 0x20, 6); |
| addChar(62, 0xffb, 12); |
| addChar(63, 0x3fc, 10); |
| addChar(64, 0x1ffa, 13); |
| addChar(65, 0x21, 6); |
| addChar(66, 0x5d, 7); |
| addChar(67, 0x5e, 7); |
| addChar(68, 0x5f, 7); |
| addChar(69, 0x60, 7); |
| addChar(70, 0x61, 7); |
| addChar(71, 0x62, 7); |
| addChar(72, 0x63, 7); |
| addChar(73, 0x64, 7); |
| addChar(74, 0x65, 7); |
| addChar(75, 0x66, 7); |
| addChar(76, 0x67, 7); |
| addChar(77, 0x68, 7); |
| addChar(78, 0x69, 7); |
| addChar(79, 0x6a, 7); |
| addChar(80, 0x6b, 7); |
| addChar(81, 0x6c, 7); |
| addChar(82, 0x6d, 7); |
| addChar(83, 0x6e, 7); |
| addChar(84, 0x6f, 7); |
| addChar(85, 0x70, 7); |
| addChar(86, 0x71, 7); |
| addChar(87, 0x72, 7); |
| addChar(88, 0xfc, 8); |
| addChar(89, 0x73, 7); |
| addChar(90, 0xfd, 8); |
| addChar(91, 0x1ffb, 13); |
| addChar(92, 0x7fff0, 19); |
| addChar(93, 0x1ffc, 13); |
| addChar(94, 0x3ffc, 14); |
| addChar(95, 0x22, 6); |
| addChar(96, 0x7ffd, 15); |
| addChar(97, 0x3, 5); |
| addChar(98, 0x23, 6); |
| addChar(99, 0x4, 5); |
| addChar(100, 0x24, 6); |
| addChar(101, 0x5, 5); |
| addChar(102, 0x25, 6); |
| addChar(103, 0x26, 6); |
| addChar(104, 0x27, 6); |
| addChar(105, 0x6, 5); |
| addChar(106, 0x74, 7); |
| addChar(107, 0x75, 7); |
| addChar(108, 0x28, 6); |
| addChar(109, 0x29, 6); |
| addChar(110, 0x2a, 6); |
| addChar(111, 0x7, 5); |
| addChar(112, 0x2b, 6); |
| addChar(113, 0x76, 7); |
| addChar(114, 0x2c, 6); |
| addChar(115, 0x8, 5); |
| addChar(116, 0x9, 5); |
| addChar(117, 0x2d, 6); |
| addChar(118, 0x77, 7); |
| addChar(119, 0x78, 7); |
| addChar(120, 0x79, 7); |
| addChar(121, 0x7a, 7); |
| addChar(122, 0x7b, 7); |
| addChar(123, 0x7ffe, 15); |
| addChar(124, 0x7fc, 11); |
| addChar(125, 0x3ffd, 14); |
| addChar(126, 0x1ffd, 13); |
| addChar(127, 0xffffffc, 28); |
| addChar(128, 0xfffe6, 20); |
| addChar(129, 0x3fffd2, 22); |
| addChar(130, 0xfffe7, 20); |
| addChar(131, 0xfffe8, 20); |
| addChar(132, 0x3fffd3, 22); |
| addChar(133, 0x3fffd4, 22); |
| addChar(134, 0x3fffd5, 22); |
| addChar(135, 0x7fffd9, 23); |
| addChar(136, 0x3fffd6, 22); |
| addChar(137, 0x7fffda, 23); |
| addChar(138, 0x7fffdb, 23); |
| addChar(139, 0x7fffdc, 23); |
| addChar(140, 0x7fffdd, 23); |
| addChar(141, 0x7fffde, 23); |
| addChar(142, 0xffffeb, 24); |
| addChar(143, 0x7fffdf, 23); |
| addChar(144, 0xffffec, 24); |
| addChar(145, 0xffffed, 24); |
| addChar(146, 0x3fffd7, 22); |
| addChar(147, 0x7fffe0, 23); |
| addChar(148, 0xffffee, 24); |
| addChar(149, 0x7fffe1, 23); |
| addChar(150, 0x7fffe2, 23); |
| addChar(151, 0x7fffe3, 23); |
| addChar(152, 0x7fffe4, 23); |
| addChar(153, 0x1fffdc, 21); |
| addChar(154, 0x3fffd8, 22); |
| addChar(155, 0x7fffe5, 23); |
| addChar(156, 0x3fffd9, 22); |
| addChar(157, 0x7fffe6, 23); |
| addChar(158, 0x7fffe7, 23); |
| addChar(159, 0xffffef, 24); |
| addChar(160, 0x3fffda, 22); |
| addChar(161, 0x1fffdd, 21); |
| addChar(162, 0xfffe9, 20); |
| addChar(163, 0x3fffdb, 22); |
| addChar(164, 0x3fffdc, 22); |
| addChar(165, 0x7fffe8, 23); |
| addChar(166, 0x7fffe9, 23); |
| addChar(167, 0x1fffde, 21); |
| addChar(168, 0x7fffea, 23); |
| addChar(169, 0x3fffdd, 22); |
| addChar(170, 0x3fffde, 22); |
| addChar(171, 0xfffff0, 24); |
| addChar(172, 0x1fffdf, 21); |
| addChar(173, 0x3fffdf, 22); |
| addChar(174, 0x7fffeb, 23); |
| addChar(175, 0x7fffec, 23); |
| addChar(176, 0x1fffe0, 21); |
| addChar(177, 0x1fffe1, 21); |
| addChar(178, 0x3fffe0, 22); |
| addChar(179, 0x1fffe2, 21); |
| addChar(180, 0x7fffed, 23); |
| addChar(181, 0x3fffe1, 22); |
| addChar(182, 0x7fffee, 23); |
| addChar(183, 0x7fffef, 23); |
| addChar(184, 0xfffea, 20); |
| addChar(185, 0x3fffe2, 22); |
| addChar(186, 0x3fffe3, 22); |
| addChar(187, 0x3fffe4, 22); |
| addChar(188, 0x7ffff0, 23); |
| addChar(189, 0x3fffe5, 22); |
| addChar(190, 0x3fffe6, 22); |
| addChar(191, 0x7ffff1, 23); |
| addChar(192, 0x3ffffe0, 26); |
| addChar(193, 0x3ffffe1, 26); |
| addChar(194, 0xfffeb, 20); |
| addChar(195, 0x7fff1, 19); |
| addChar(196, 0x3fffe7, 22); |
| addChar(197, 0x7ffff2, 23); |
| addChar(198, 0x3fffe8, 22); |
| addChar(199, 0x1ffffec, 25); |
| addChar(200, 0x3ffffe2, 26); |
| addChar(201, 0x3ffffe3, 26); |
| addChar(202, 0x3ffffe4, 26); |
| addChar(203, 0x7ffffde, 27); |
| addChar(204, 0x7ffffdf, 27); |
| addChar(205, 0x3ffffe5, 26); |
| addChar(206, 0xfffff1, 24); |
| addChar(207, 0x1ffffed, 25); |
| addChar(208, 0x7fff2, 19); |
| addChar(209, 0x1fffe3, 21); |
| addChar(210, 0x3ffffe6, 26); |
| addChar(211, 0x7ffffe0, 27); |
| addChar(212, 0x7ffffe1, 27); |
| addChar(213, 0x3ffffe7, 26); |
| addChar(214, 0x7ffffe2, 27); |
| addChar(215, 0xfffff2, 24); |
| addChar(216, 0x1fffe4, 21); |
| addChar(217, 0x1fffe5, 21); |
| addChar(218, 0x3ffffe8, 26); |
| addChar(219, 0x3ffffe9, 26); |
| addChar(220, 0xffffffd, 28); |
| addChar(221, 0x7ffffe3, 27); |
| addChar(222, 0x7ffffe4, 27); |
| addChar(223, 0x7ffffe5, 27); |
| addChar(224, 0xfffec, 20); |
| addChar(225, 0xfffff3, 24); |
| addChar(226, 0xfffed, 20); |
| addChar(227, 0x1fffe6, 21); |
| addChar(228, 0x3fffe9, 22); |
| addChar(229, 0x1fffe7, 21); |
| addChar(230, 0x1fffe8, 21); |
| addChar(231, 0x7ffff3, 23); |
| addChar(232, 0x3fffea, 22); |
| addChar(233, 0x3fffeb, 22); |
| addChar(234, 0x1ffffee, 25); |
| addChar(235, 0x1ffffef, 25); |
| addChar(236, 0xfffff4, 24); |
| addChar(237, 0xfffff5, 24); |
| addChar(238, 0x3ffffea, 26); |
| addChar(239, 0x7ffff4, 23); |
| addChar(240, 0x3ffffeb, 26); |
| addChar(241, 0x7ffffe6, 27); |
| addChar(242, 0x3ffffec, 26); |
| addChar(243, 0x3ffffed, 26); |
| addChar(244, 0x7ffffe7, 27); |
| addChar(245, 0x7ffffe8, 27); |
| addChar(246, 0x7ffffe9, 27); |
| addChar(247, 0x7ffffea, 27); |
| addChar(248, 0x7ffffeb, 27); |
| addChar(249, 0xffffffe, 28); |
| addChar(250, 0x7ffffec, 27); |
| addChar(251, 0x7ffffed, 27); |
| addChar(252, 0x7ffffee, 27); |
| addChar(253, 0x7ffffef, 27); |
| addChar(254, 0x7fffff0, 27); |
| addChar(255, 0x3ffffee, 26); |
| addEOS (256, EOS.code, EOS.length); |
| // @formatter:on |
| } |
| |
| |
| /** |
| * Calculates the number of bytes required to represent the given {@code |
| * CharSequence} with the Huffman coding. |
| * |
| * @param value |
| * characters |
| * |
| * @return number of bytes |
| * |
| * @throws NullPointerException |
| * if the value is null |
| */ |
| public int lengthOf(CharSequence value) { |
| return lengthOf(value, 0, value.length()); |
| } |
| |
| /** |
| * Calculates the number of bytes required to represent a subsequence of the |
| * given {@code CharSequence} with the Huffman coding. |
| * |
| * @param value |
| * characters |
| * @param start |
| * the start index, inclusive |
| * @param end |
| * the end index, exclusive |
| * |
| * @return number of bytes |
| * |
| * @throws NullPointerException |
| * if the value is null |
| * @throws IndexOutOfBoundsException |
| * if any invocation of {@code value.charAt(i)}, where |
| * {@code start <= i < end} would throw an IndexOutOfBoundsException |
| */ |
| public int lengthOf(CharSequence value, int start, int end) { |
| int len = 0; |
| for (int i = start; i < end; i++) { |
| char c = value.charAt(i); |
| len += INSTANCE.codeOf(c).length; |
| } |
| // Integer division with ceiling, assumption: |
| assert (len / 8 + (len % 8 != 0 ? 1 : 0)) == (len + 7) / 8 : len; |
| return (len + 7) / 8; |
| } |
| |
| private void addChar(int c, int code, int bitLength) { |
| addLeaf(c, code, bitLength, false); |
| codes[c] = new Code(code, bitLength); |
| } |
| |
| private void addEOS(int c, int code, int bitLength) { |
| addLeaf(c, code, bitLength, true); |
| codes[c] = new Code(code, bitLength); |
| } |
| |
| private void addLeaf(int c, int code, int bitLength, boolean isEOS) { |
| if (bitLength < 1) { |
| throw new IllegalArgumentException("bitLength < 1"); |
| } |
| Node curr = root; |
| for (int p = 1 << bitLength - 1; p != 0 && !curr.isLeaf(); p = p >> 1) { |
| curr.isEOSPath |= isEOS; // If it's already true, it can't become false |
| curr = curr.addChildIfAbsent(p & code); |
| } |
| curr.isEOSPath |= isEOS; // The last one needs to have this property as well |
| if (curr.isLeaf()) { |
| throw new IllegalStateException("Specified code is already taken"); |
| } |
| curr.setChar((char) c); |
| } |
| |
| private Code codeOf(char c) { |
| if (c > 255) { |
| throw new IllegalArgumentException("char=" + ((int) c)); |
| } |
| return codes[c]; |
| } |
| |
| // |
| // For debugging/testing purposes |
| // |
| Node getRoot() { |
| return root; |
| } |
| |
| // |
| // Guarantees: |
| // |
| // if (isLeaf() == true) => getChar() is a legal call |
| // if (isLeaf() == false) => getChild(i) is a legal call (though it can |
| // return null) |
| // |
| static class Node { |
| |
| Node left; |
| Node right; |
| boolean isEOSPath; |
| |
| boolean charIsSet; |
| char c; |
| |
| Node getChild(int selector) { |
| if (isLeaf()) { |
| throw new IllegalStateException("This is a leaf node"); |
| } |
| Node result = selector == 0 ? left : right; |
| if (result == null) { |
| throw new IllegalStateException(format( |
| "Node doesn't have a child (selector=%s)", selector)); |
| } |
| return result; |
| } |
| |
| boolean isLeaf() { |
| return charIsSet; |
| } |
| |
| char getChar() { |
| if (!isLeaf()) { |
| throw new IllegalStateException("This node is not a leaf node"); |
| } |
| return c; |
| } |
| |
| void setChar(char c) { |
| if (charIsSet) { |
| throw new IllegalStateException( |
| "This node has been taken already"); |
| } |
| if (left != null || right != null) { |
| throw new IllegalStateException("The node cannot be made " |
| + "a leaf as it's already has a child"); |
| } |
| this.c = c; |
| charIsSet = true; |
| } |
| |
| Node addChildIfAbsent(int i) { |
| if (charIsSet) { |
| throw new IllegalStateException("The node cannot have a child " |
| + "as it's already a leaf node"); |
| } |
| Node child; |
| if (i == 0) { |
| if ((child = left) == null) { |
| child = left = new Node(); |
| } |
| } else { |
| if ((child = right) == null) { |
| child = right = new Node(); |
| } |
| } |
| return child; |
| } |
| |
| @Override |
| public String toString() { |
| if (isLeaf()) { |
| if (isEOSPath) { |
| return "EOS"; |
| } else { |
| return format("char: (%3s) '%s'", (int) c, c); |
| } |
| } |
| return "/\\"; |
| } |
| } |
| |
| // TODO: value-based class? |
| // FIXME: can we re-use Node instead of this class? |
| private static final class Code { |
| |
| final int code; |
| final int length; |
| |
| private Code(int code, int length) { |
| this.code = code; |
| this.length = length; |
| } |
| |
| public int getCode() { |
| return code; |
| } |
| |
| public int getLength() { |
| return length; |
| } |
| |
| @Override |
| public String toString() { |
| long p = 1 << length; |
| return Long.toBinaryString(code + p).substring(1) |
| + ", length=" + length; |
| } |
| } |
| } |
