1 /*
2 * Copyright (C) 2012 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 * http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17 /*
18 * Store data bytes in a variable-size queue.
19 */
20
21 #include "DataQueue.h"
22
23 #include <malloc.h>
24 #include <string.h>
25
26 #include <android-base/stringprintf.h>
27 #include <base/logging.h>
28
29 using android::base::StringPrintf;
30 /*******************************************************************************
31 **
32 ** Function: DataQueue
33 **
34 ** Description: Initialize member variables.
35 **
36 ** Returns: None.
37 **
38 *******************************************************************************/
DataQueue()39 DataQueue::DataQueue() {}
40
41 /*******************************************************************************
42 **
43 ** Function: ~DataQueue
44 **
45 ** Description: Release all resources.
46 **
47 ** Returns: None.
48 **
49 *******************************************************************************/
~DataQueue()50 DataQueue::~DataQueue() {
51 mMutex.lock();
52 while (mQueue.empty() == false) {
53 tHeader* header = mQueue.front();
54 mQueue.pop_front();
55 free(header);
56 }
57 mMutex.unlock();
58 }
59
isEmpty()60 bool DataQueue::isEmpty() {
61 mMutex.lock();
62 bool retval = mQueue.empty();
63 mMutex.unlock();
64 return retval;
65 }
66
67 /*******************************************************************************
68 **
69 ** Function: enqueue
70 **
71 ** Description: Append data to the queue.
72 ** data: array of bytes
73 ** dataLen: length of the data.
74 **
75 ** Returns: True if ok.
76 **
77 *******************************************************************************/
enqueue(uint8_t * data,uint16_t dataLen)78 bool DataQueue::enqueue(uint8_t* data, uint16_t dataLen) {
79 if ((data == NULL) || (dataLen == 0)) return false;
80
81 mMutex.lock();
82
83 bool retval = false;
84 tHeader* header = (tHeader*)malloc(sizeof(tHeader) + dataLen);
85
86 if (header) {
87 memset(header, 0, sizeof(tHeader));
88 header->mDataLen = dataLen;
89 memcpy(header + 1, data, dataLen);
90
91 mQueue.push_back(header);
92
93 retval = true;
94 } else {
95 LOG(ERROR) << StringPrintf("DataQueue::enqueue: out of memory ?????");
96 }
97 mMutex.unlock();
98 return retval;
99 }
100
101 /*******************************************************************************
102 **
103 ** Function: dequeue
104 **
105 ** Description: Retrieve and remove data from the front of the queue.
106 ** buffer: array to store the data.
107 ** bufferMaxLen: maximum size of the buffer.
108 ** actualLen: actual length of the data.
109 **
110 ** Returns: True if ok.
111 **
112 *******************************************************************************/
dequeue(uint8_t * buffer,uint16_t bufferMaxLen,uint16_t & actualLen)113 bool DataQueue::dequeue(uint8_t* buffer, uint16_t bufferMaxLen,
114 uint16_t& actualLen) {
115 mMutex.lock();
116
117 tHeader* header = mQueue.front();
118 bool retval = false;
119
120 if (header && buffer && (bufferMaxLen > 0)) {
121 if (header->mDataLen <= bufferMaxLen) {
122 // caller's buffer is big enough to store all data
123 actualLen = header->mDataLen;
124 char* src = (char*)(header) + sizeof(tHeader) + header->mOffset;
125 memcpy(buffer, src, actualLen);
126
127 mQueue.pop_front();
128 free(header);
129 } else {
130 // caller's buffer is too small
131 actualLen = bufferMaxLen;
132 char* src = (char*)(header) + sizeof(tHeader) + header->mOffset;
133 memcpy(buffer, src, actualLen);
134 // adjust offset so the next dequeue() will get the remainder
135 header->mDataLen -= actualLen;
136 header->mOffset += actualLen;
137 }
138 retval = true;
139 }
140 mMutex.unlock();
141 return retval;
142 }
143