1/*
2 * Copyright (c) 2000-2004,2011,2014 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#include "bufferfifo.h"
29#include <security_utilities/memutils.h>
30
31
32namespace Security {
33
34
35//
36// On destruction, throw away all queued buffers (that haven't been picked up)
37//
38BufferFifo::~BufferFifo()
39{
40    while (!mBuffers.empty()) {
41        delete mBuffers.front();
42        mBuffers.pop();
43    }
44}
45
46void BufferFifo::clearBuffer()
47{
48    while (!mBuffers.empty()) {
49        delete mBuffers.front();
50        mBuffers.pop();
51    }
52    mSize = 0;
53}
54
55//
56// This is the put function of a Sink. We store the data in at most two buffers:
57// First we append to the last (partially filled) one; then we allocate a new one
58// (if needed) to hold the rest.
59//
60void BufferFifo::consume(const void *data, size_t size)
61{
62    mSize += size;
63
64    // step 1: fill the rearmost (partially filled) buffer
65    if (size > 0 && !mBuffers.empty()) {
66        Buffer *current = mBuffers.back();
67        size_t length = current->put(data, size);
68        data = LowLevelMemoryUtilities::increment(data, length);
69        size -= length;
70    }
71    // step 2: if there's anything left, make a new buffer and fill it
72    if (size > 0) {	// not done
73        Buffer *current = new Buffer(max(bufferLength, size));
74        mBuffers.push(current);
75        assert(current->available() >= size);
76        current->put(data, size);
77    }
78}
79
80
81//
82// Pull the first (FI) buffer off the queue and deliver it.
83// We retain no memory of it; it belongs to the caller now.
84//
85Buffer *BufferFifo::pop()
86{
87    assert(!mBuffers.empty());
88    Buffer *top = mBuffers.front();
89    mBuffers.pop();
90    return top;
91}
92
93
94}	// end namespace Security
95