1 files changed, 75 insertions, 0 deletions
diff --git a/services/audioflinger/MonoPipeReader.cpp b/services/audioflinger/MonoPipeReader.cpp
new file mode 100644
index 0000000..b80d0c0
--- /dev/null
+++ b/services/audioflinger/MonoPipeReader.cpp
@@ -0,0 +1,75 @@
+/*
+ * Copyright (C) 2012 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.
+ */
+
+#define LOG_TAG "MonoPipeReader"
+//#define LOG_NDEBUG 0
+
+#include <cutils/compiler.h>
+#include <utils/Log.h>
+#include "MonoPipeReader.h"
+
+namespace android {
+
+MonoPipeReader::MonoPipeReader(MonoPipe* pipe) :
+        NBAIO_Source(pipe->mFormat),
+        mPipe(pipe)
+{
+}
+
+MonoPipeReader::~MonoPipeReader()
+{
+}
+
+ssize_t MonoPipeReader::availableToRead()
+{
+    if (CC_UNLIKELY(!mNegotiated)) {
+        return NEGOTIATE;
+    }
+    ssize_t ret = android_atomic_acquire_load(&mPipe->mRear) - mPipe->mFront;
+    ALOG_ASSERT((0 <= ret) && (ret <= mMaxFrames));
+    return ret;
+}
+
+ssize_t MonoPipeReader::read(void *buffer, size_t count)
+{
+    // count == 0 is unlikely and not worth checking for explicitly; will be handled automatically
+    ssize_t red = availableToRead();
+    if (CC_UNLIKELY(red <= 0)) {
+        return red;
+    }
+    if (CC_LIKELY((size_t) red > count)) {
+        red = count;
+    }
+    size_t front = mPipe->mFront & (mPipe->mMaxFrames - 1);
+    size_t part1 = mPipe->mMaxFrames - front;
+    if (part1 > (size_t) red) {
+        part1 = red;
+    }
+    if (CC_LIKELY(part1 > 0)) {
+        memcpy(buffer, (char *) mPipe->mBuffer + (front << mBitShift), part1 << mBitShift);
+        if (CC_UNLIKELY(front + part1 == mPipe->mMaxFrames)) {
+            size_t part2 = red - part1;
+            if (CC_LIKELY(part2 > 0)) {
+                memcpy((char *) buffer + (part1 << mBitShift), mPipe->mBuffer, part2 << mBitShift);
+            }
+        }
+        android_atomic_release_store(red + mPipe->mFront, &mPipe->mFront);
+        mFramesRead += red;
+    }
+    return red;
+}
+
+}   // namespace android