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
33struct input_event;
34
35InputEventCircularReader::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
44InputEventCircularReader::~InputEventCircularReader()
45{
46    delete [] mBuffer;
47}
48
49ssize_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
74ssize_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
81void InputEventCircularReader::next()
82{
83    mCurr++;
84    mFreeSpace++;
85    if (mCurr >= mBufferEnd) {
86        mCurr = mBuffer;
87    }
88}
89