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 <poll.h>
20 #include <string.h>
21 #include <unistd.h>
22
23 #include <sys/cdefs.h>
24 #include <sys/types.h>
25
26 #include <linux/input.h>
27
28 #include <cutils/log.h>
29
30 #include "InputEventReader.h"
31
32 /*****************************************************************************/
33
34 struct input_event;
35
InputEventCircularReader(size_t numEvents)36 InputEventCircularReader::InputEventCircularReader(size_t numEvents)
37 : mBuffer(new input_event[numEvents * 2]),
38 mBufferEnd(mBuffer + numEvents),
39 mHead(mBuffer),
40 mCurr(mBuffer),
41 mFreeSpace(numEvents)
42 {
43 }
44
~InputEventCircularReader()45 InputEventCircularReader::~InputEventCircularReader()
46 {
47 delete [] mBuffer;
48 }
49
fill(int fd)50 ssize_t InputEventCircularReader::fill(int fd)
51 {
52 size_t numEventsRead = 0;
53 if (mFreeSpace) {
54 const ssize_t nread = read(fd, mHead, mFreeSpace * sizeof(input_event));
55 if (nread<0 || nread % sizeof(input_event)) {
56 // we got a partial event!!
57 return nread<0 ? -errno : -EINVAL;
58 }
59
60 numEventsRead = nread / sizeof(input_event);
61 if (numEventsRead) {
62 mHead += numEventsRead;
63 mFreeSpace -= numEventsRead;
64 if (mHead > mBufferEnd) {
65 size_t s = mHead - mBufferEnd;
66 memcpy(mBuffer, mBufferEnd, s * sizeof(input_event));
67 mHead = mBuffer + s;
68 }
69 }
70 }
71
72 return numEventsRead;
73 }
74
readEvent(input_event const ** events)75 ssize_t InputEventCircularReader::readEvent(input_event const** events)
76 {
77 *events = mCurr;
78 ssize_t available = (mBufferEnd - mBuffer) - mFreeSpace;
79 return available ? 1 : 0;
80 }
81
next()82 void InputEventCircularReader::next()
83 {
84 mCurr++;
85 mFreeSpace++;
86 if (mCurr >= mBufferEnd) {
87 mCurr = mBuffer;
88 }
89 }
90