--- /dev/null Thu Jan 01 00:00:00 1970 +0000
+++ b/src/java.net.http/share/classes/jdk/internal/net/http/hpack/Huffman.java Wed Feb 07 21:45:37 2018 +0000
@@ -0,0 +1,681 @@
+/*
+ * 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 Huffman {
+
+ // TODO: check if reset is done in both reader and writer
+
+ static final class 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();
+ }
+
+ 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");
+ }
+
+ public void reset() {
+ curr = INSTANCE.root;
+ len = 0;
+ resetProbe();
+ }
+
+ private void resetProbe() {
+ p = 0x80;
+ }
+ }
+
+ static final class 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;
+
+ 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;
+ }
+
+ 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;
+ }
+
+ public Writer reset() {
+ source = null;
+ end = -1;
+ pos = -1;
+ avail = 8;
+ curr = 0;
+ code = 0;
+ return this;
+ }
+ }
+
+ /**
+ * Shared instance.
+ */
+ public static final Huffman INSTANCE = new Huffman();
+
+ 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 Huffman() {
+ // @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;
+ }
+ }
+}