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99 lines
4.0 KiB
C++
99 lines
4.0 KiB
C++
/* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
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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 Communicator client code, released
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* March 31, 1998.
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*
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* The Initial Developer of the Original Code is
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* Netscape Communications Corporation.
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* Portions created by the Initial Developer are Copyright (C) 1998-1999
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* the Initial Developer. All Rights Reserved.
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*
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* Contributor(s):
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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 of the GNU General Public License Version 2 or later (the "GPL"),
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* or 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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/*
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* The storage stream provides an internal buffer that can be filled by a
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* client using a single output stream. One or more independent input streams
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* can be created to read the data out non-destructively. The implementation
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* uses a segmented buffer internally to avoid realloc'ing of large buffers,
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* with the attendant performance loss and heap fragmentation.
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*/
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#ifndef _nsStorageStream_h_
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#define _nsStorageStream_h_
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#include "nsIStorageStream.h"
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#include "nsIOutputStream.h"
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#include "nsMemory.h"
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#define NS_STORAGESTREAM_CID \
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{ /* 669a9795-6ff7-4ed4-9150-c34ce2971b63 */ \
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0x669a9795, \
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0x6ff7, \
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0x4ed4, \
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{0x91, 0x50, 0xc3, 0x4c, 0xe2, 0x97, 0x1b, 0x63} \
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}
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#define NS_STORAGESTREAM_CONTRACTID "@mozilla.org/storagestream;1"
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#define NS_STORAGESTREAM_CLASSNAME "Storage Stream"
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class nsSegmentedBuffer;
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class nsStorageStream : public nsIStorageStream,
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public nsIOutputStream
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{
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public:
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nsStorageStream();
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NS_DECL_ISUPPORTS
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NS_DECL_NSISTORAGESTREAM
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NS_DECL_NSIOUTPUTSTREAM
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friend class nsStorageInputStream;
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private:
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~nsStorageStream();
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nsSegmentedBuffer* mSegmentedBuffer;
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PRUint32 mSegmentSize; // All segments, except possibly the last, are of this size
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// Must be power-of-2
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PRUint32 mSegmentSizeLog2; // log2(mSegmentSize)
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PRBool mWriteInProgress; // true, if an un-Close'ed output stream exists
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PRInt32 mLastSegmentNum; // Last segment # in use, -1 initially
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char* mWriteCursor; // Pointer to next byte to be written
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char* mSegmentEnd; // Pointer to one byte after end of segment
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// containing the write cursor
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PRUint32 mLogicalLength; // Number of bytes written to stream
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NS_METHOD Seek(PRInt32 aPosition);
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PRUint32 SegNum(PRUint32 aPosition) {return aPosition >> mSegmentSizeLog2;}
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PRUint32 SegOffset(PRUint32 aPosition) {return aPosition & (mSegmentSize - 1);}
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};
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#endif // _nsStorageStream_h_
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