From 16f504a9dca3fe3b70568f67b7d41241ae485288 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 18:49:04 +0200 Subject: Adding upstream version 7.0.6-dfsg. Signed-off-by: Daniel Baumann --- src/libs/xpcom18a4/xpcom/io/nsSegmentedBuffer.h | 125 ++++++++++++++++++++++++ 1 file changed, 125 insertions(+) create mode 100644 src/libs/xpcom18a4/xpcom/io/nsSegmentedBuffer.h (limited to 'src/libs/xpcom18a4/xpcom/io/nsSegmentedBuffer.h') diff --git a/src/libs/xpcom18a4/xpcom/io/nsSegmentedBuffer.h b/src/libs/xpcom18a4/xpcom/io/nsSegmentedBuffer.h new file mode 100644 index 00000000..43620632 --- /dev/null +++ b/src/libs/xpcom18a4/xpcom/io/nsSegmentedBuffer.h @@ -0,0 +1,125 @@ +/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 4 -*- */ +/* ***** BEGIN LICENSE BLOCK ***** + * Version: MPL 1.1/GPL 2.0/LGPL 2.1 + * + * The contents of this file are subject to the Mozilla Public License Version + * 1.1 (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.mozilla.org/MPL/ + * + * Software distributed under the License is distributed on an "AS IS" basis, + * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License + * for the specific language governing rights and limitations under the + * License. + * + * The Original Code is mozilla.org code. + * + * The Initial Developer of the Original Code is + * Netscape Communications Corporation. + * Portions created by the Initial Developer are Copyright (C) 1998 + * the Initial Developer. All Rights Reserved. + * + * Contributor(s): + * + * Alternatively, the contents of this file may be used under the terms of + * either of the GNU General Public License Version 2 or later (the "GPL"), + * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"), + * in which case the provisions of the GPL or the LGPL are applicable instead + * of those above. If you wish to allow use of your version of this file only + * under the terms of either the GPL or the LGPL, and not to allow others to + * use your version of this file under the terms of the MPL, indicate your + * decision by deleting the provisions above and replace them with the notice + * and other provisions required by the GPL or the LGPL. If you do not delete + * the provisions above, a recipient may use your version of this file under + * the terms of any one of the MPL, the GPL or the LGPL. + * + * ***** END LICENSE BLOCK ***** */ + +#ifndef nsSegmentedBuffer_h__ +#define nsSegmentedBuffer_h__ + +#include "nsMemory.h" +#include "prclist.h" + +class nsSegmentedBuffer +{ +public: + nsSegmentedBuffer() + : mSegmentSize(0), mMaxSize(0), + mSegAllocator(nsnull), mSegmentArray(nsnull), + mSegmentArrayCount(0), + mFirstSegmentIndex(0), mLastSegmentIndex(0) {} + + ~nsSegmentedBuffer() { + Empty(); + NS_IF_RELEASE(mSegAllocator); + } + + + NS_COM nsresult Init(PRUint32 segmentSize, PRUint32 maxSize, + nsIMemory* allocator = nsnull); + + NS_COM char* AppendNewSegment(); // pushes at end + + // returns true if no more segments remain: + PRBool DeleteFirstSegment(); // pops from beginning + + // returns true if no more segments remain: + PRBool DeleteLastSegment(); // pops from beginning + + // Call Realloc() on last segment. This is used to reduce memory + // consumption when data is not an exact multiple of segment size. + PRBool ReallocLastSegment(size_t newSize); + + NS_COM void Empty(); // frees all segments + + inline PRUint32 GetSegmentCount() { + if (mFirstSegmentIndex <= mLastSegmentIndex) + return mLastSegmentIndex - mFirstSegmentIndex; + else + return mSegmentArrayCount + mLastSegmentIndex - mFirstSegmentIndex; + } + + inline PRUint32 GetSegmentSize() { return mSegmentSize; } + inline PRUint32 GetMaxSize() { return mMaxSize; } + inline PRUint32 GetSize() { return GetSegmentCount() * mSegmentSize; } + + inline char* GetSegment(PRUint32 indx) { + NS_ASSERTION(indx < GetSegmentCount(), "index out of bounds"); + PRInt32 i = ModSegArraySize(mFirstSegmentIndex + (PRInt32)indx); + return mSegmentArray[i]; + } + +protected: + inline PRInt32 ModSegArraySize(PRInt32 n) { + PRUint32 result = n & (mSegmentArrayCount - 1); + NS_ASSERTION(result == n % mSegmentArrayCount, + "non-power-of-2 mSegmentArrayCount"); + return result; + } + + inline PRBool IsFull() { + return ModSegArraySize(mLastSegmentIndex + 1) == mFirstSegmentIndex; + } + +protected: + PRUint32 mSegmentSize; + PRUint32 mMaxSize; + nsIMemory* mSegAllocator; + char** mSegmentArray; + PRUint32 mSegmentArrayCount; + PRInt32 mFirstSegmentIndex; + PRInt32 mLastSegmentIndex; +}; + +// NS_SEGMENTARRAY_INITIAL_SIZE: This number needs to start out as a +// power of 2 given how it gets used. We double the segment array +// when we overflow it, and use that fact that it's a power of 2 +// to compute a fast modulus operation in IsFull. +// +// 32 segment array entries can accommodate 128k of data if segments +// are 4k in size. That seems like a reasonable amount that will avoid +// needing to grow the segment array. +#define NS_SEGMENTARRAY_INITIAL_COUNT 32 + +#endif // nsSegmentedBuffer_h__ -- cgit v1.2.3