зеркало из https://github.com/mozilla/pjs.git
117 строки
3.7 KiB
C++
117 строки
3.7 KiB
C++
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*- */
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/* vim:set ts=4 sw=4 sts=4 et cindent: */
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/* ***** BEGIN LICENSE BLOCK *****
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* Version: MPL 1.1/GPL 2.0/LGPL 2.1
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*
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* The contents of this file are subject to the Mozilla Public License Version
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* 1.1 (the "License"); you may not use this file except in compliance with
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* 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" basis,
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* WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
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* for the specific language governing rights and limitations under the
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* License.
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*
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* The Original Code is Mozilla code.
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*
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* The Initial Developer of the Original Code is the Mozilla Foundation.
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* Portions created by the Initial Developer are Copyright (C) 2011
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* the Initial Developer. All Rights Reserved.
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*
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* Contributor(s):
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* Jeff Muizelaar <jmuizelaar@mozilla.com>
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*
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* Alternatively, the contents of this file may be used under the terms of
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* either the GNU General Public License Version 2 or later (the "GPL"), or
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* the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
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* in which case the provisions of the GPL or the LGPL are applicable instead
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* of those above. If you wish to allow use of your version of this file only
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* under the terms of either the GPL or the LGPL, and not to allow others to
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* use your version of this file under the terms of the MPL, indicate your
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* decision by deleting the provisions above and replace them with the notice
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* and other provisions required by the GPL or the LGPL. If you do not delete
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* the provisions above, a recipient may use your version of this file under
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* the terms of any one of the MPL, the GPL or the LGPL.
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*
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* ***** END LICENSE BLOCK ***** */
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/* We would use std::max but MS makes it painful
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// windef.h defines min and max macros that we don't want
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// http://support.microsoft.com/kb/143208
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#ifdef _WIN32
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#define NOMINMAX
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#endif
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*/
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#include <stdlib.h>
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#include <string.h>
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#include "nsAlgorithm.h"
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/* This is a standard string builder like ones in Java
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or C#. It uses a doubling allocation strategy
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to grow when out of capacity.
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This does not use nsTArray because nsTArray starts
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growing by multiples of page size after it is the
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size of one page. We want to keep doubling in size
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so that we can continue to append at high speed even
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for large strings.
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Eventually, this should be templated for wide characters.
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*/
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namespace mozilla {
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class StringBuilder
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{
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public:
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StringBuilder() {
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mCapacity = 16;
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mLength = 0;
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mBuffer = static_cast<char*>(malloc(sizeof(char)*mCapacity));
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mBuffer[0] = '\0';
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}
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void Append(const char *s) {
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size_t newLength = strlen(s);
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EnsureCapacity(mLength + newLength+1);
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// copy the entire string including the null terminator
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memcpy(&mBuffer[mLength], s, newLength+1);
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mLength += newLength;
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}
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char *Buffer() {
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return mBuffer;
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}
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size_t Length() {
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return mLength;
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}
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size_t EnsureCapacity(size_t capacity) {
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if (capacity > mCapacity) {
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// make sure we at least double in size
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mCapacity = NS_MAX(capacity, mCapacity*2);
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mBuffer = static_cast<char*>(realloc(mBuffer, mCapacity));
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mCapacity = moz_malloc_usable_size(mBuffer);
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}
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return mCapacity;
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}
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~StringBuilder()
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{
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free(mBuffer);
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}
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private:
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char *mBuffer;
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size_t mLength; // the length of the contained string not including the null terminator
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size_t mCapacity; // the total size of mBuffer
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};
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}
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