JP Abgrall | 5dcc6c9 | 2012-05-31 20:39:43 -0700 | [diff] [blame] | 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 | template <typename T> |
| 34 | static inline T min(T a, T b) { |
| 35 | return a<b ? a : b; |
| 36 | } |
| 37 | |
| 38 | struct iio_event_data; |
| 39 | |
| 40 | InputEventCircularReader::InputEventCircularReader(size_t numEvents) |
| 41 | : mBuffer(new iio_event_data[numEvents]), |
| 42 | mBufferEnd(mBuffer + numEvents), |
| 43 | mHead(mBuffer), |
| 44 | mCurr(mBuffer), |
| 45 | mMaxEvents(numEvents), |
| 46 | mFreeEvents(numEvents) |
| 47 | { |
| 48 | } |
| 49 | |
| 50 | InputEventCircularReader::~InputEventCircularReader() |
| 51 | { |
| 52 | delete [] mBuffer; |
| 53 | } |
| 54 | |
| 55 | ssize_t InputEventCircularReader::fill(int fd) |
| 56 | { |
| 57 | size_t numEventsRead = 0; |
| 58 | if (mFreeEvents) { |
| 59 | struct iovec iov[2]; |
| 60 | |
| 61 | const size_t numFirst = min(mFreeEvents, (size_t)(mBufferEnd - mHead)); |
| 62 | const ssize_t numSecond = mFreeEvents - numFirst; |
| 63 | |
| 64 | int iovcnt = 1; |
| 65 | iov[0].iov_base = mHead; |
| 66 | iov[0].iov_len = numFirst * sizeof(iio_event_data); |
| 67 | |
| 68 | if (numSecond > 0) { |
| 69 | iovcnt++; |
| 70 | iov[1].iov_base = mBuffer; |
| 71 | iov[1].iov_len = numSecond * sizeof(iio_event_data); |
| 72 | } |
| 73 | |
| 74 | const ssize_t nread = readv(fd, iov, iovcnt); |
| 75 | if (nread < 0 || nread % sizeof(iio_event_data)) { |
| 76 | // we got a partial event!! |
| 77 | return nread < 0 ? -errno : -EINVAL; |
| 78 | } |
| 79 | |
| 80 | numEventsRead = nread / sizeof(iio_event_data); |
| 81 | if (numEventsRead) { |
| 82 | mHead += numEventsRead; |
| 83 | mFreeEvents -= numEventsRead; |
| 84 | if (mHead >= mBufferEnd) |
| 85 | mHead -= mMaxEvents; |
| 86 | } |
| 87 | } |
| 88 | |
| 89 | return numEventsRead; |
| 90 | } |
| 91 | |
| 92 | bool InputEventCircularReader::readEvent(int fd, iio_event_data const** events) |
| 93 | { |
| 94 | if (mFreeEvents >= mMaxEvents) { |
| 95 | ssize_t eventCount = fill(fd); |
| 96 | if (eventCount <= 0) |
| 97 | return false; |
| 98 | } |
| 99 | *events = mCurr; |
| 100 | return true; |
| 101 | } |
| 102 | |
| 103 | void InputEventCircularReader::next() |
| 104 | { |
| 105 | mCurr++; |
| 106 | if (mCurr >= mBufferEnd) { |
| 107 | mCurr = mBuffer; |
| 108 | } |
| 109 | if (mFreeEvents < mMaxEvents) { |
| 110 | mFreeEvents++; |
| 111 | } |
| 112 | } |