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/*
* Copyright (C) 2012 The Android Open Source Project
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
* You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS,
* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
* See the License for the specific language governing permissions and
* limitations under the License.
*/
/*
* Store data bytes in a variable-size queue.
*/
#include "DataQueue.h"
/*******************************************************************************
**
** Function: DataQueue
**
** Description: Initialize member variables.
**
** Returns: None.
**
*******************************************************************************/
DataQueue::DataQueue ()
{
}
/*******************************************************************************
**
** Function: ~DataQueue
**
** Description: Release all resources.
**
** Returns: None.
**
*******************************************************************************/
DataQueue::~DataQueue ()
{
mMutex.lock ();
while (mQueue.empty() == false)
{
tHeader* header = mQueue.front ();
mQueue.pop_front ();
free (header);
}
mMutex.unlock ();
}
bool DataQueue::isEmpty()
{
mMutex.lock ();
bool retval = mQueue.empty();
mMutex.unlock ();
return retval;
}
/*******************************************************************************
**
** Function: enqueue
**
** Description: Append data to the queue.
** data: array of bytes
** dataLen: length of the data.
**
** Returns: True if ok.
**
*******************************************************************************/
bool DataQueue::enqueue (UINT8* data, UINT16 dataLen)
{
if ((data == NULL) || (dataLen==0))
return false;
mMutex.lock ();
bool retval = false;
tHeader* header = (tHeader*) malloc (sizeof(tHeader) + dataLen);
if (header)
{
memset (header, 0, sizeof(tHeader));
header->mDataLen = dataLen;
memcpy (header+1, data, dataLen);
mQueue.push_back (header);
retval = true;
}
else
{
ALOGE ("DataQueue::enqueue: out of memory ?????");
}
mMutex.unlock ();
return retval;
}
/*******************************************************************************
**
** Function: dequeue
**
** Description: Retrieve and remove data from the front of the queue.
** buffer: array to store the data.
** bufferMaxLen: maximum size of the buffer.
** actualLen: actual length of the data.
**
** Returns: True if ok.
**
*******************************************************************************/
bool DataQueue::dequeue (UINT8* buffer, UINT16 bufferMaxLen, UINT16& actualLen)
{
mMutex.lock ();
tHeader* header = mQueue.front ();
bool retval = false;
if (header && buffer && (bufferMaxLen>0))
{
if (header->mDataLen <= bufferMaxLen)
{
//caller's buffer is big enough to store all data
actualLen = header->mDataLen;
char* src = (char*)(header) + sizeof(tHeader) + header->mOffset;
memcpy (buffer, src, actualLen);
mQueue.pop_front ();
free (header);
}
else
{
//caller's buffer is too small
actualLen = bufferMaxLen;
char* src = (char*)(header) + sizeof(tHeader) + header->mOffset;
memcpy (buffer, src, actualLen);
//adjust offset so the next dequeue() will get the remainder
header->mDataLen -= actualLen;
header->mOffset += actualLen;
}
retval = true;
}
mMutex.unlock ();
return retval;
}
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