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