зеркало из https://github.com/mozilla/pjs.git
115 строки
3.2 KiB
Java
115 строки
3.2 KiB
Java
/* -*- Mode: java; indent-tabs-mode: nil; c-basic-offset: 2 -*-
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*
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* The contents of this file are subject to the Mozilla Public License
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* Version 1.0 (the "License"); you may not use this file except in
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* compliance with the License. You may obtain a copy of the License at
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* http://www.mozilla.org/MPL/
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*
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* Software distributed under the License is distributed on an "AS IS"
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* basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See
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* the License for the specific language governing rights and limitations
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* under the License.
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*
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* The Original Code is the Grendel mail/news client.
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*
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* The Initial Developer of the Original Code is Netscape Communications
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* Corporation. Portions created by Netscape are Copyright (C) 1997
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* Netscape Communications Corporation. All Rights Reserved.
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*/
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package grendel.storage;
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import calypso.util.Assert;
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import calypso.util.ByteBuf;
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/** Represents a set of bytes. This is a spiritual cousin of String,
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but without the misfeature that characters are two bytes each, and
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there are 16 bytes of extranious object header. Since we store
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message headers internally in their on-the-wire form, and that
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is 7-bit ASCII (and occasionally 8-bit if people are being
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nonstandard) this is a much more tolerable representation.
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<P>
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This class doesn't provide all of the utilities that String does,
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but that's pretty much just because I didn't need them (yet?)
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<P>
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this is used by ByteStringTable to uniqueify the strings, to
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further reduce memory usage.
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@see ByteStringTable
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@see MessageID
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*/
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class ByteString {
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protected byte[] bytes;
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// Warning, don't add more instance variables unless you're really
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// really sure. There are zillions of these objects, so they should
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// be as small as we can make them.
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ByteString(byte bytes[]) {
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this.bytes = bytes; // this bites! ha ha.
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}
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ByteString(ByteBuf buf) {
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bytes = new byte[buf.length()];
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System.arraycopy(bytes, 0, buf.toBytes(), 0, bytes.length);
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}
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public String toString() {
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return new String(bytes);
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}
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public ByteBuf toByteBuf() {
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return new ByteBuf(bytes, 0, bytes.length);
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}
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public byte[] toBytes() {
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return bytes;
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}
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protected int hashBytes(byte b[], int start, int len) {
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// Copied from java.lang.String.hashCode() and adapted to work
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// on bytes instead of characters.
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int h = 0;
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int off = start;
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int end = start + len;
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if (len < 16) {
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for (int i = len ; i > 0; i--) {
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h = (h * 37) + bytes[off++];
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}
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} else {
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// only sample some characters
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int skip = len / 8;
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for (int i = len ; i > 0; i -= skip, off += skip) {
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h = (h * 39) + bytes[off];
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}
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}
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return h;
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}
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public int hashCode() {
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return hashBytes(bytes, 0, bytes.length);
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}
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public boolean equals(Object x) {
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if (x instanceof ByteString) {
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int L = bytes.length;
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ByteString ix = (ByteString) x;
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if (L != ix.bytes.length)
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return false;
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else {
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for (int i = 0; i < L; i++) {
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if (bytes[i] != ix.bytes[i])
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return false;
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}
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return true;
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}
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}
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else
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return false;
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}
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}
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