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1 /*
2  * Copyright (C) 2008 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 #include <stdint.h>
18 #include <errno.h>
19 #include <unistd.h>
20 #include <poll.h>
21 
22 #include <sys/cdefs.h>
23 #include <sys/types.h>
24 
25 #include <linux/input.h>
26 
27 #include <cutils/log.h>
28 
29 #include "InputEventReader.h"
30 
31 /*****************************************************************************/
32 
33 struct input_event;
34 
InputEventCircularReader(size_t numEvents)35 InputEventCircularReader::InputEventCircularReader(size_t numEvents)
36     : mBuffer(new input_event[numEvents * 2]),
37       mBufferEnd(mBuffer + numEvents),
38       mHead(mBuffer),
39       mCurr(mBuffer),
40       mFreeSpace(numEvents)
41 {
42 }
43 
~InputEventCircularReader()44 InputEventCircularReader::~InputEventCircularReader()
45 {
46     delete [] mBuffer;
47 }
48 
fill(int fd)49 ssize_t InputEventCircularReader::fill(int fd)
50 {
51     size_t numEventsRead = 0;
52     if (mFreeSpace) {
53         const ssize_t nread = read(fd, mHead, mFreeSpace * sizeof(input_event));
54         if (nread<0 || nread % sizeof(input_event)) {
55             // we got a partial event!!
56             return nread<0 ? -errno : -EINVAL;
57         }
58 
59         numEventsRead = nread / sizeof(input_event);
60         if (numEventsRead) {
61             mHead += numEventsRead;
62             mFreeSpace -= numEventsRead;
63             if (mHead > mBufferEnd) {
64                 size_t s = mHead - mBufferEnd;
65                 memcpy(mBuffer, mBufferEnd, s * sizeof(input_event));
66                 mHead = mBuffer + s;
67             }
68         }
69     }
70 
71     return numEventsRead;
72 }
73 
readEvent(input_event const ** events)74 ssize_t InputEventCircularReader::readEvent(input_event const** events)
75 {
76     *events = mCurr;
77     ssize_t available = (mBufferEnd - mBuffer) - mFreeSpace;
78     return available ? 1 : 0;
79 }
80 
next()81 void InputEventCircularReader::next()
82 {
83     mCurr++;
84     mFreeSpace++;
85     if (mCurr >= mBufferEnd) {
86         mCurr = mBuffer;
87     }
88 }
89