1/*
2 * Copyright (c) 2000-2002,2004,2011,2014 Apple Inc. All Rights Reserved.
3 *
4 * @APPLE_LICENSE_HEADER_START@
5 *
6 * This file contains Original Code and/or Modifications of Original Code
7 * as defined in and that are subject to the Apple Public Source License
8 * Version 2.0 (the 'License'). You may not use this file except in
9 * compliance with the License. Please obtain a copy of the License at
10 * http://www.opensource.apple.com/apsl/ and read it before using this
11 * file.
12 *
13 * The Original Code and all software distributed under the License are
14 * distributed on an 'AS IS' basis, WITHOUT WARRANTY OF ANY KIND, EITHER
15 * EXPRESS OR IMPLIED, AND APPLE HEREBY DISCLAIMS ALL SUCH WARRANTIES,
16 * INCLUDING WITHOUT LIMITATION, ANY WARRANTIES OF MERCHANTABILITY,
17 * FITNESS FOR A PARTICULAR PURPOSE, QUIET ENJOYMENT OR NON-INFRINGEMENT.
18 * Please see the License for the specific language governing rights and
19 * limitations under the License.
20 *
21 * @APPLE_LICENSE_HEADER_END@
22 */
23
24
25//
26// bufferfifo - a Sink that queues data in a FIFO of buffers for retrieval
27//
28#ifndef _H_BUFFERFIFO
29#define _H_BUFFERFIFO
30
31#include "streams.h"
32#include "buffers.h"
33#include <list>
34#include <queue>
35
36
37namespace Security {
38
39
40//
41// A BufferFifo acts as a First-in First-out queue of Buffer objects.
42// This is usually used as a flexible I/O buffer queue mechanism.
43// For convenience, a BufferFifo is a Sink, so you can push data
44// into it directly using the Sink mechanism.
45// Note that there is currently no mechanism for restricting the
46// memory footprint of a BufferFifo.
47//
48class BufferFifo : public Sink {
49public:
50    BufferFifo(size_t es = 4096) : bufferLength(es) { }
51    ~BufferFifo();
52
53    Buffer *top() const			{ assert(!mBuffers.empty()); return mBuffers.front(); }
54    Buffer *pop();
55    void push(Buffer *b)		{ mBuffers.push(b); }
56
57    bool isEmpty() const		{ return mBuffers.empty(); }
58    size_t size() const			{ return mBuffers.size(); }
59    size_t topLength() const	{ assert(!isEmpty()); return mBuffers.front()->length(); }
60
61    // Sink implementation
62    void consume(const void *data, size_t size);
63    void clearBuffer();
64
65private:
66    typedef queue< Buffer *, list<Buffer *> > BufferQueue;
67    BufferQueue mBuffers;
68    const size_t bufferLength;
69};
70
71
72
73}	// end namespace Security
74
75
76#endif /* _H_BUFFERFIFO */
77