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 <android-base/logging.h>
24 #include <android-base/stringprintf.h>
25 #include <malloc.h>
26 #include <string.h>
27
28 using android::base::StringPrintf;
29 /*******************************************************************************
30 **
31 ** Function: DataQueue
32 **
33 ** Description: Initialize member variables.
34 **
35 ** Returns: None.
36 **
37 *******************************************************************************/
DataQueue()38 DataQueue::DataQueue() {}
39
40 /*******************************************************************************
41 **
42 ** Function: ~DataQueue
43 **
44 ** Description: Release all resources.
45 **
46 ** Returns: None.
47 **
48 *******************************************************************************/
~DataQueue()49 DataQueue::~DataQueue() {
50 mMutex.lock();
51 while (mQueue.empty() == false) {
52 tHeader* header = mQueue.front();
53 mQueue.pop_front();
54 free(header);
55 }
56 mMutex.unlock();
57 }
58
isEmpty()59 bool DataQueue::isEmpty() {
60 mMutex.lock();
61 bool retval = mQueue.empty();
62 mMutex.unlock();
63 return retval;
64 }
65
66 /*******************************************************************************
67 **
68 ** Function: enqueue
69 **
70 ** Description: Append data to the queue.
71 ** data: array of bytes
72 ** dataLen: length of the data.
73 **
74 ** Returns: True if ok.
75 **
76 *******************************************************************************/
enqueue(uint8_t * data,uint16_t dataLen)77 bool DataQueue::enqueue(uint8_t* data, uint16_t dataLen) {
78 if ((data == NULL) || (dataLen == 0)) return false;
79
80 mMutex.lock();
81
82 bool retval = false;
83 tHeader* header = (tHeader*)malloc(sizeof(tHeader) + dataLen);
84
85 if (header) {
86 memset(header, 0, sizeof(tHeader));
87 header->mDataLen = dataLen;
88 memcpy(header + 1, data, dataLen);
89
90 mQueue.push_back(header);
91
92 retval = true;
93 } else {
94 LOG(ERROR) << StringPrintf("DataQueue::enqueue: out of memory ?????");
95 }
96 mMutex.unlock();
97 return retval;
98 }
99
100 /*******************************************************************************
101 **
102 ** Function: dequeue
103 **
104 ** Description: Retrieve and remove data from the front of the queue.
105 ** buffer: array to store the data.
106 ** bufferMaxLen: maximum size of the buffer.
107 ** actualLen: actual length of the data.
108 **
109 ** Returns: True if ok.
110 **
111 *******************************************************************************/
dequeue(uint8_t * buffer,uint16_t bufferMaxLen,uint16_t & actualLen)112 bool DataQueue::dequeue(uint8_t* buffer, uint16_t bufferMaxLen,
113 uint16_t& actualLen) {
114 mMutex.lock();
115
116 tHeader* header = mQueue.front();
117 bool retval = false;
118
119 if (header && buffer && (bufferMaxLen > 0)) {
120 if (header->mDataLen <= bufferMaxLen) {
121 // caller's buffer is big enough to store all data
122 actualLen = header->mDataLen;
123 char* src = (char*)(header) + sizeof(tHeader) + header->mOffset;
124 memcpy(buffer, src, actualLen);
125
126 mQueue.pop_front();
127 free(header);
128 } else {
129 // caller's buffer is too small
130 actualLen = bufferMaxLen;
131 char* src = (char*)(header) + sizeof(tHeader) + header->mOffset;
132 memcpy(buffer, src, actualLen);
133 // adjust offset so the next dequeue() will get the remainder
134 header->mDataLen -= actualLen;
135 header->mOffset += actualLen;
136 }
137 retval = true;
138 }
139 mMutex.unlock();
140 return retval;
141 }
142