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      1 /*
      2  * Copyright (C) 2011 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 package android.hardware;
     18 
     19 import android.os.ParcelFileDescriptor;
     20 import android.util.Log;
     21 
     22 import java.io.FileDescriptor;
     23 import java.io.FileInputStream;
     24 import java.io.FileOutputStream;
     25 import java.io.InputStream;
     26 import java.io.IOException;
     27 import java.io.OutputStream;
     28 
     29 import java.nio.ByteBuffer;
     30 
     31 /**
     32  * @hide
     33  */
     34 public class SerialPort {
     35 
     36     private static final String TAG = "SerialPort";
     37 
     38     // used by the JNI code
     39     private int mNativeContext;
     40     private final String mName;
     41     private ParcelFileDescriptor mFileDescriptor;
     42 
     43     /**
     44      * SerialPort should only be instantiated by SerialManager
     45      * @hide
     46      */
     47     public SerialPort(String name) {
     48         mName = name;
     49     }
     50 
     51     /**
     52      * SerialPort should only be instantiated by SerialManager
     53      * Speed must be one of 50, 75, 110, 134, 150, 200, 300, 600, 1200, 1800, 2400, 4800, 9600,
     54      * 19200, 38400, 57600, 115200, 230400, 460800, 500000, 576000, 921600, 1000000, 1152000,
     55      * 1500000, 2000000, 2500000, 3000000, 3500000, 4000000
     56      *
     57      * @hide
     58      */
     59     public void open(ParcelFileDescriptor pfd, int speed) throws IOException {
     60         native_open(pfd.getFileDescriptor(), speed);
     61         mFileDescriptor = pfd;
     62     }
     63 
     64     /**
     65      * Closes the serial port
     66      */
     67     public void close() throws IOException {
     68         if (mFileDescriptor != null) {
     69             mFileDescriptor.close();
     70             mFileDescriptor = null;
     71         }
     72         native_close();
     73     }
     74 
     75     /**
     76      * Returns the name of the serial port
     77      *
     78      * @return the serial port's name
     79      */
     80     public String getName() {
     81         return mName;
     82     }
     83 
     84     /**
     85      * Reads data into the provided buffer.
     86      * Note that the value returned by {@link java.nio.Buffer#position()} on this buffer is
     87      * unchanged after a call to this method.
     88      *
     89      * @param buffer to read into
     90      * @return number of bytes read
     91      */
     92     public int read(ByteBuffer buffer) throws IOException {
     93         if (buffer.isDirect()) {
     94             return native_read_direct(buffer, buffer.remaining());
     95         } else if (buffer.hasArray()) {
     96             return native_read_array(buffer.array(), buffer.remaining());
     97         } else {
     98             throw new IllegalArgumentException("buffer is not direct and has no array");
     99         }
    100     }
    101 
    102     /**
    103      * Writes data from provided buffer.
    104      * Note that the value returned by {@link java.nio.Buffer#position()} on this buffer is
    105      * unchanged after a call to this method.
    106      *
    107      * @param buffer to write
    108      * @param length number of bytes to write
    109      */
    110     public void write(ByteBuffer buffer, int length) throws IOException {
    111         if (buffer.isDirect()) {
    112             native_write_direct(buffer, length);
    113         } else if (buffer.hasArray()) {
    114             native_write_array(buffer.array(), length);
    115         } else {
    116             throw new IllegalArgumentException("buffer is not direct and has no array");
    117         }
    118     }
    119 
    120     /**
    121      * Sends a stream of zero valued bits for 0.25 to 0.5 seconds
    122      */
    123     public void sendBreak() {
    124         native_send_break();
    125     }
    126 
    127     private native void native_open(FileDescriptor pfd, int speed) throws IOException;
    128     private native void native_close();
    129     private native int native_read_array(byte[] buffer, int length) throws IOException;
    130     private native int native_read_direct(ByteBuffer buffer, int length) throws IOException;
    131     private native void native_write_array(byte[] buffer, int length) throws IOException;
    132     private native void native_write_direct(ByteBuffer buffer, int length) throws IOException;
    133     private native void native_send_break();
    134 }
    135