1 files changed, 111 insertions, 0 deletions
diff --git a/libsensors/InputEventReader.cpp b/libsensors/InputEventReader.cpp
new file mode 100644
index 0000000..964eda5
--- /dev/null
+++ b/libsensors/InputEventReader.cpp
@@ -0,0 +1,111 @@
+/*
+ * Copyright (C) 2008 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#include <stdint.h>
+#include <errno.h>
+#include <unistd.h>
+#include <poll.h>
+
+#include <sys/cdefs.h>
+#include <sys/types.h>
+
+#include <linux/input.h>
+
+#include <cutils/log.h>
+
+#include "InputEventReader.h"
+
+/*****************************************************************************/
+
+template <typename T>
+static inline T min(T a, T b) {
+    return a<b ? a : b;
+}
+
+struct input_event;
+
+InputEventCircularReader::InputEventCircularReader(size_t numEvents)
+    : mBuffer(new input_event[numEvents]),
+      mBufferEnd(mBuffer + numEvents),
+      mHead(mBuffer),
+      mCurr(mBuffer),
+      mEvents(numEvents),
+      mFreeSpace(numEvents)
+{
+}
+
+InputEventCircularReader::~InputEventCircularReader()
+{
+    delete [] mBuffer;
+}
+
+ssize_t InputEventCircularReader::fill(int fd)
+{
+    size_t numEventsRead = 0;
+    if (mFreeSpace) {
+        struct iovec iov[2];
+
+        const size_t numFirst = min(mFreeSpace, (size_t)(mBufferEnd - mHead));
+        const size_t numSecond = mFreeSpace - numFirst;
+
+        int iovcnt = 1;
+        iov[0].iov_base = mHead;
+        iov[0].iov_len = numFirst * sizeof(input_event);
+
+        if (numSecond > 0)
+        {
+            iovcnt++;
+            iov[1].iov_base = mBuffer;
+            iov[1].iov_len = numSecond * sizeof(input_event);
+        }
+
+        const ssize_t nread = readv(fd, iov, iovcnt);
+        if (nread < 0 || nread % sizeof(input_event)) {
+            // we got a partial event!!
+            return nread < 0 ? -errno : -EINVAL;
+        }
+
+        numEventsRead = nread / sizeof(input_event);
+        if (numEventsRead) {
+            mHead += numEventsRead;
+            mFreeSpace -= numEventsRead;
+            if (mHead >= mBufferEnd)
+                mHead -= mBufferEnd - mBuffer;
+        }
+    }
+
+    return numEventsRead;
+}
+
+bool InputEventCircularReader::readEvent(int fd, input_event const** events)
+{
+    if (mFreeSpace >= mEvents) {
+        ssize_t eventCount = fill(fd);
+        if (eventCount <= 0)
+            return false;
+    }
+    *events = mCurr;
+    return true;
+}
+
+void InputEventCircularReader::next()
+{
+    mCurr++;
+    mFreeSpace++;
+    if (mCurr >= mBufferEnd) {
+        mCurr = mBuffer;
+    }
+}