1 : /* -*- Mode: C++; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 4 -*-
2 : * ***** BEGIN LICENSE BLOCK *****
3 : * Version: MPL 1.1/GPL 2.0/LGPL 2.1
4 : *
5 : * The contents of this file are subject to the Mozilla Public License Version
6 : * 1.1 (the "License"); you may not use this file except in compliance with
7 : * the License. You may obtain a copy of the License at
8 : * http://www.mozilla.org/MPL/
9 : *
10 : * Software distributed under the License is distributed on an "AS IS" basis,
11 : * WITHOUT WARRANTY OF ANY KIND, either express or implied. See the License
12 : * for the specific language governing rights and limitations under the
13 : * License.
14 : *
15 : * The Original Code is Mozilla Communicator client code, released
16 : * March 31, 1998.
17 : *
18 : * The Initial Developer of the Original Code is
19 : * Netscape Communications Corporation.
20 : * Portions created by the Initial Developer are Copyright (C) 1998-1999
21 : * the Initial Developer. All Rights Reserved.
22 : *
23 : * Contributor(s):
24 : *
25 : * Alternatively, the contents of this file may be used under the terms of
26 : * either of the GNU General Public License Version 2 or later (the "GPL"),
27 : * or the GNU Lesser General Public License Version 2.1 or later (the "LGPL"),
28 : * in which case the provisions of the GPL or the LGPL are applicable instead
29 : * of those above. If you wish to allow use of your version of this file only
30 : * under the terms of either the GPL or the LGPL, and not to allow others to
31 : * use your version of this file under the terms of the MPL, indicate your
32 : * decision by deleting the provisions above and replace them with the notice
33 : * and other provisions required by the GPL or the LGPL. If you do not delete
34 : * the provisions above, a recipient may use your version of this file under
35 : * the terms of any one of the MPL, the GPL or the LGPL.
36 : *
37 : * ***** END LICENSE BLOCK ***** */
38 :
39 : /*
40 : * The storage stream provides an internal buffer that can be filled by a
41 : * client using a single output stream. One or more independent input streams
42 : * can be created to read the data out non-destructively. The implementation
43 : * uses a segmented buffer internally to avoid realloc'ing of large buffers,
44 : * with the attendant performance loss and heap fragmentation.
45 : */
46 :
47 : #ifndef _nsStorageStream_h_
48 : #define _nsStorageStream_h_
49 :
50 : #include "nsIStorageStream.h"
51 : #include "nsIOutputStream.h"
52 : #include "nsMemory.h"
53 :
54 : #define NS_STORAGESTREAM_CID \
55 : { /* 669a9795-6ff7-4ed4-9150-c34ce2971b63 */ \
56 : 0x669a9795, \
57 : 0x6ff7, \
58 : 0x4ed4, \
59 : {0x91, 0x50, 0xc3, 0x4c, 0xe2, 0x97, 0x1b, 0x63} \
60 : }
61 :
62 : #define NS_STORAGESTREAM_CONTRACTID "@mozilla.org/storagestream;1"
63 : #define NS_STORAGESTREAM_CLASSNAME "Storage Stream"
64 :
65 : class nsSegmentedBuffer;
66 :
67 : class nsStorageStream : public nsIStorageStream,
68 : public nsIOutputStream
69 : {
70 : public:
71 : nsStorageStream();
72 :
73 : NS_DECL_ISUPPORTS
74 : NS_DECL_NSISTORAGESTREAM
75 : NS_DECL_NSIOUTPUTSTREAM
76 :
77 : friend class nsStorageInputStream;
78 :
79 : private:
80 : ~nsStorageStream();
81 :
82 : nsSegmentedBuffer* mSegmentedBuffer;
83 : PRUint32 mSegmentSize; // All segments, except possibly the last, are of this size
84 : // Must be power-of-2
85 : PRUint32 mSegmentSizeLog2; // log2(mSegmentSize)
86 : bool mWriteInProgress; // true, if an un-Close'ed output stream exists
87 : PRInt32 mLastSegmentNum; // Last segment # in use, -1 initially
88 : char* mWriteCursor; // Pointer to next byte to be written
89 : char* mSegmentEnd; // Pointer to one byte after end of segment
90 : // containing the write cursor
91 : PRUint32 mLogicalLength; // Number of bytes written to stream
92 :
93 : NS_METHOD Seek(PRInt32 aPosition);
94 783 : PRUint32 SegNum(PRUint32 aPosition) {return aPosition >> mSegmentSizeLog2;}
95 8984 : PRUint32 SegOffset(PRUint32 aPosition) {return aPosition & (mSegmentSize - 1);}
96 : };
97 :
98 : #endif // _nsStorageStream_h_
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