java/org/apache/coyote/http2/Hpack.java - tomcat - Git at Google

 /*
  *  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 org.apache.tomcat.util.res.StringManager;

 final class Hpack {

     private static final StringManager sm = StringManager.getManager(Hpack.class);

     private static final byte LOWER_DIFF = 'a' - 'A';
     static final int DEFAULT_TABLE_SIZE = 4096;
     private static final int MAX_INTEGER_OCTETS = 8; //not sure what a good value for this is, but the spec says we need to provide an upper bound

     /**
      * table that contains powers of two,
      * used as both bitmask and to quickly calculate 2^n
      */
     private static final int[] PREFIX_TABLE;


     static final HeaderField[] STATIC_TABLE;
     static final int STATIC_TABLE_LENGTH;

     static {
         PREFIX_TABLE = new int[32];
         for (int i = 0; i < 32; ++i) {
             int n = 0;
             for (int j = 0; j < i; ++j) {
                 n = n << 1;
                 n |= 1;
             }
             PREFIX_TABLE[i] = n;
         }

         HeaderField[] fields = new HeaderField[62];
         //note that zero is not used
         fields[1] = new HeaderField(":authority", null);
         fields[2] = new HeaderField(":method", "GET");
         fields[3] = new HeaderField(":method", "POST");
         fields[4] = new HeaderField(":path", "/");
         fields[5] = new HeaderField(":path", "/index.html");
         fields[6] = new HeaderField(":scheme", "http");
         fields[7] = new HeaderField(":scheme", "https");
         fields[8] = new HeaderField(":status", "200");
         fields[9] = new HeaderField(":status", "204");
         fields[10] = new HeaderField(":status", "206");
         fields[11] = new HeaderField(":status", "304");
         fields[12] = new HeaderField(":status", "400");
         fields[13] = new HeaderField(":status", "404");
         fields[14] = new HeaderField(":status", "500");
         fields[15] = new HeaderField("accept-charset", null);
         fields[16] = new HeaderField("accept-encoding", "gzip, deflate");
         fields[17] = new HeaderField("accept-language", null);
         fields[18] = new HeaderField("accept-ranges", null);
         fields[19] = new HeaderField("accept", null);
         fields[20] = new HeaderField("access-control-allow-origin", null);
         fields[21] = new HeaderField("age", null);
         fields[22] = new HeaderField("allow", null);
         fields[23] = new HeaderField("authorization", null);
         fields[24] = new HeaderField("cache-control", null);
         fields[25] = new HeaderField("content-disposition", null);
         fields[26] = new HeaderField("content-encoding", null);
         fields[27] = new HeaderField("content-language", null);
         fields[28] = new HeaderField("content-length", null);
         fields[29] = new HeaderField("content-location", null);
         fields[30] = new HeaderField("content-range", null);
         fields[31] = new HeaderField("content-type", null);
         fields[32] = new HeaderField("cookie", null);
         fields[33] = new HeaderField("date", null);
         fields[34] = new HeaderField("etag", null);
         fields[35] = new HeaderField("expect", null);
         fields[36] = new HeaderField("expires", null);
         fields[37] = new HeaderField("from", null);
         fields[38] = new HeaderField("host", null);
         fields[39] = new HeaderField("if-match", null);
         fields[40] = new HeaderField("if-modified-since", null);
         fields[41] = new HeaderField("if-none-match", null);
         fields[42] = new HeaderField("if-range", null);
         fields[43] = new HeaderField("if-unmodified-since", null);
         fields[44] = new HeaderField("last-modified", null);
         fields[45] = new HeaderField("link", null);
         fields[46] = new HeaderField("location", null);
         fields[47] = new HeaderField("max-forwards", null);
         fields[48] = new HeaderField("proxy-authenticate", null);
         fields[49] = new HeaderField("proxy-authorization", null);
         fields[50] = new HeaderField("range", null);
         fields[51] = new HeaderField("referer", null);
         fields[52] = new HeaderField("refresh", null);
         fields[53] = new HeaderField("retry-after", null);
         fields[54] = new HeaderField("server", null);
         fields[55] = new HeaderField("set-cookie", null);
         fields[56] = new HeaderField("strict-transport-security", null);
         fields[57] = new HeaderField("transfer-encoding", null);
         fields[58] = new HeaderField("user-agent", null);
         fields[59] = new HeaderField("vary", null);
         fields[60] = new HeaderField("via", null);
         fields[61] = new HeaderField("www-authenticate", null);
         STATIC_TABLE = fields;
         STATIC_TABLE_LENGTH = STATIC_TABLE.length - 1;
     }

     static class HeaderField {
         final String name;
         final String value;
         final int size;

         HeaderField(String name, String value) {
             this.name = name;
             this.value = value;
             if (value != null) {
                 this.size = 32 + name.length() + value.length();
             } else {
                 this.size = -1;
             }
         }
     }

     /**
      * Decodes an integer in the HPACK prefix format. If the return value is -1
      * it means that there was not enough data in the buffer to complete the decoding
      * sequence.
      * <p/>
      * If this method returns -1 then the source buffer will not have been modified.
      *
      * @param source The buffer that contains the integer
      * @param n      The encoding prefix length
      * @return The encoded integer, or -1 if there was not enough data
      */
     static int decodeInteger(ByteBuffer source, int n) throws HpackException {
         if (source.remaining() == 0) {
             return -1;
         }
         int count = 1;
         int sp = source.position();
         int mask = PREFIX_TABLE[n];

         int i = mask & source.get();
         int b;
         if (i < PREFIX_TABLE[n]) {
             return i;
         } else {
             int m = 0;
             do {
                 if(count++ > MAX_INTEGER_OCTETS) {
                     throw new HpackException(sm.getString("hpack.integerEncodedOverTooManyOctets",
                             Integer.valueOf(MAX_INTEGER_OCTETS)));
                 }
                 if (source.remaining() == 0) {
                     //we have run out of data
                     //reset
                     source.position(sp);
                     return -1;
                 }
                 b = source.get();
                 i = i + (b & 127) * (PREFIX_TABLE[m] + 1);
                 m += 7;
             } while ((b & 128) == 128);
         }
         return i;
     }

     /**
      * Encodes an integer in the HPACK prefix format.
      * <p/>
      * This method assumes that the buffer has already had the first 8-n bits filled.
      * As such it will modify the last byte that is already present in the buffer, and
      * potentially add more if required
      *
      * @param source The buffer that contains the integer
      * @param value  The integer to encode
      * @param n      The encoding prefix length
      */
     static void encodeInteger(ByteBuffer source, int value, int n) {
         int twoNminus1 = PREFIX_TABLE[n];
         int pos = source.position() - 1;
         if (value < twoNminus1) {
             source.put(pos, (byte) (source.get(pos) | value));
         } else {
             source.put(pos, (byte) (source.get(pos) | twoNminus1));
             value = value - twoNminus1;
             while (value >= 128) {
                 source.put((byte) (value % 128 + 128));
                 value = value / 128;
             }
             source.put((byte) value);
         }
     }


     static char toLower(char c) {
         if (c >= 'A' && c <= 'Z') {
             return (char) (c + LOWER_DIFF);
         }
         return c;
     }

     private Hpack() {}

 }
	/*
	* 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 org.apache.tomcat.util.res.StringManager;

	final class Hpack {

	private static final StringManager sm = StringManager.getManager(Hpack.class);

	private static final byte LOWER_DIFF = 'a' - 'A';
	static final int DEFAULT_TABLE_SIZE = 4096;
	private static final int MAX_INTEGER_OCTETS = 8; //not sure what a good value for this is, but the spec says we need to provide an upper bound

	/**
	* table that contains powers of two,
	* used as both bitmask and to quickly calculate 2^n
	*/
	private static final int[] PREFIX_TABLE;


	static final HeaderField[] STATIC_TABLE;
	static final int STATIC_TABLE_LENGTH;

	static {
	PREFIX_TABLE = new int[32];
	for (int i = 0; i < 32; ++i) {
	int n = 0;
	for (int j = 0; j < i; ++j) {
	n = n << 1;
	n \|= 1;
	}
	PREFIX_TABLE[i] = n;
	}

	HeaderField[] fields = new HeaderField[62];
	//note that zero is not used
	fields[1] = new HeaderField(":authority", null);
	fields[2] = new HeaderField(":method", "GET");
	fields[3] = new HeaderField(":method", "POST");
	fields[4] = new HeaderField(":path", "/");
	fields[5] = new HeaderField(":path", "/index.html");
	fields[6] = new HeaderField(":scheme", "http");
	fields[7] = new HeaderField(":scheme", "https");
	fields[8] = new HeaderField(":status", "200");
	fields[9] = new HeaderField(":status", "204");
	fields[10] = new HeaderField(":status", "206");
	fields[11] = new HeaderField(":status", "304");
	fields[12] = new HeaderField(":status", "400");
	fields[13] = new HeaderField(":status", "404");
	fields[14] = new HeaderField(":status", "500");
	fields[15] = new HeaderField("accept-charset", null);
	fields[16] = new HeaderField("accept-encoding", "gzip, deflate");
	fields[17] = new HeaderField("accept-language", null);
	fields[18] = new HeaderField("accept-ranges", null);
	fields[19] = new HeaderField("accept", null);
	fields[20] = new HeaderField("access-control-allow-origin", null);
	fields[21] = new HeaderField("age", null);
	fields[22] = new HeaderField("allow", null);
	fields[23] = new HeaderField("authorization", null);
	fields[24] = new HeaderField("cache-control", null);
	fields[25] = new HeaderField("content-disposition", null);
	fields[26] = new HeaderField("content-encoding", null);
	fields[27] = new HeaderField("content-language", null);
	fields[28] = new HeaderField("content-length", null);
	fields[29] = new HeaderField("content-location", null);
	fields[30] = new HeaderField("content-range", null);
	fields[31] = new HeaderField("content-type", null);
	fields[32] = new HeaderField("cookie", null);
	fields[33] = new HeaderField("date", null);
	fields[34] = new HeaderField("etag", null);
	fields[35] = new HeaderField("expect", null);
	fields[36] = new HeaderField("expires", null);
	fields[37] = new HeaderField("from", null);
	fields[38] = new HeaderField("host", null);
	fields[39] = new HeaderField("if-match", null);
	fields[40] = new HeaderField("if-modified-since", null);
	fields[41] = new HeaderField("if-none-match", null);
	fields[42] = new HeaderField("if-range", null);
	fields[43] = new HeaderField("if-unmodified-since", null);
	fields[44] = new HeaderField("last-modified", null);
	fields[45] = new HeaderField("link", null);
	fields[46] = new HeaderField("location", null);
	fields[47] = new HeaderField("max-forwards", null);
	fields[48] = new HeaderField("proxy-authenticate", null);
	fields[49] = new HeaderField("proxy-authorization", null);
	fields[50] = new HeaderField("range", null);
	fields[51] = new HeaderField("referer", null);
	fields[52] = new HeaderField("refresh", null);
	fields[53] = new HeaderField("retry-after", null);
	fields[54] = new HeaderField("server", null);
	fields[55] = new HeaderField("set-cookie", null);
	fields[56] = new HeaderField("strict-transport-security", null);
	fields[57] = new HeaderField("transfer-encoding", null);
	fields[58] = new HeaderField("user-agent", null);
	fields[59] = new HeaderField("vary", null);
	fields[60] = new HeaderField("via", null);
	fields[61] = new HeaderField("www-authenticate", null);
	STATIC_TABLE = fields;
	STATIC_TABLE_LENGTH = STATIC_TABLE.length - 1;
	}

	static class HeaderField {
	final String name;
	final String value;
	final int size;

	HeaderField(String name, String value) {
	this.name = name;
	this.value = value;
	if (value != null) {
	this.size = 32 + name.length() + value.length();
	} else {
	this.size = -1;
	}
	}
	}

	/**
	* Decodes an integer in the HPACK prefix format. If the return value is -1
	* it means that there was not enough data in the buffer to complete the decoding
	* sequence.
	* <p/>
	* If this method returns -1 then the source buffer will not have been modified.
	*
	* @param source The buffer that contains the integer
	* @param n The encoding prefix length
	* @return The encoded integer, or -1 if there was not enough data
	*/
	static int decodeInteger(ByteBuffer source, int n) throws HpackException {
	if (source.remaining() == 0) {
	return -1;
	}
	int count = 1;
	int sp = source.position();
	int mask = PREFIX_TABLE[n];

	int i = mask & source.get();
	int b;
	if (i < PREFIX_TABLE[n]) {
	return i;
	} else {
	int m = 0;
	do {
	if(count++ > MAX_INTEGER_OCTETS) {
	throw new HpackException(sm.getString("hpack.integerEncodedOverTooManyOctets",
	Integer.valueOf(MAX_INTEGER_OCTETS)));
	}
	if (source.remaining() == 0) {
	//we have run out of data
	//reset
	source.position(sp);
	return -1;
	}
	b = source.get();
	i = i + (b & 127) * (PREFIX_TABLE[m] + 1);
	m += 7;
	} while ((b & 128) == 128);
	}
	return i;
	}

	/**
	* Encodes an integer in the HPACK prefix format.
	* <p/>
	* This method assumes that the buffer has already had the first 8-n bits filled.
	* As such it will modify the last byte that is already present in the buffer, and
	* potentially add more if required
	*
	* @param source The buffer that contains the integer
	* @param value The integer to encode
	* @param n The encoding prefix length
	*/
	static void encodeInteger(ByteBuffer source, int value, int n) {
	int twoNminus1 = PREFIX_TABLE[n];
	int pos = source.position() - 1;
	if (value < twoNminus1) {
	source.put(pos, (byte) (source.get(pos) \| value));
	} else {
	source.put(pos, (byte) (source.get(pos) \| twoNminus1));
	value = value - twoNminus1;
	while (value >= 128) {
	source.put((byte) (value % 128 + 128));
	value = value / 128;
	}
	source.put((byte) value);
	}
	}


	static char toLower(char c) {
	if (c >= 'A' && c <= 'Z') {
	return (char) (c + LOWER_DIFF);
	}
	return c;
	}

	private Hpack() {}

	}