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      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 #pragma once
     22 #include <list>
     23 #include "Mutex.h"
     24 #include "NfcJniUtil.h"
     25 #include "gki.h"
     26 
     27 class DataQueue {
     28  public:
     29   /*******************************************************************************
     30   **
     31   ** Function:        DataQueue
     32   **
     33   ** Description:     Initialize member variables.
     34   **
     35   ** Returns:         None.
     36   **
     37   *******************************************************************************/
     38   DataQueue();
     39 
     40   /*******************************************************************************
     41   **
     42   ** Function:        ~DataQueue
     43   **
     44   ** Description:      Release all resources.
     45   **
     46   ** Returns:         None.
     47   **
     48   *******************************************************************************/
     49   ~DataQueue();
     50 
     51   /*******************************************************************************
     52   **
     53   ** Function:        enqueue
     54   **
     55   ** Description:     Append data to the queue.
     56   **                  data: array of bytes
     57   **                  dataLen: length of the data.
     58   **
     59   ** Returns:         True if ok.
     60   **
     61   *******************************************************************************/
     62   bool enqueue(uint8_t* data, uint16_t dataLen);
     63 
     64   /*******************************************************************************
     65   **
     66   ** Function:        dequeue
     67   **
     68   ** Description:     Retrieve and remove data from the front of the queue.
     69   **                  buffer: array to store the data.
     70   **                  bufferMaxLen: maximum size of the buffer.
     71   **                  actualLen: actual length of the data.
     72   **
     73   ** Returns:         True if ok.
     74   **
     75   *******************************************************************************/
     76   bool dequeue(uint8_t* buffer, uint16_t bufferMaxLen, uint16_t& actualLen);
     77 
     78   /*******************************************************************************
     79   **
     80   ** Function:        isEmpty
     81   **
     82   ** Description:     Whether the queue is empty.
     83   **
     84   ** Returns:         True if empty.
     85   **
     86   *******************************************************************************/
     87   bool isEmpty();
     88 
     89  private:
     90   struct tHeader {
     91     uint16_t mDataLen;  // number of octets of data
     92     uint16_t mOffset;   // offset of the first octet of data
     93   };
     94   typedef std::list<tHeader*> Queue;
     95 
     96   Queue mQueue;
     97   Mutex mMutex;
     98 };
     99