1 files changed, 182 insertions, 0 deletions
diff --git a/libs/rs/rsLocklessFifo.cpp b/libs/rs/rsLocklessFifo.cpp
new file mode 100644
index 0000000..67ab434
--- /dev/null
+++ b/libs/rs/rsLocklessFifo.cpp
@@ -0,0 +1,182 @@
+/*
+ * Copyright (C) 2009 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 "rsLocklessFifo.h"
+
+using namespace android;
+
+#include <utils/Log.h>
+
+LocklessCommandFifo::LocklessCommandFifo()
+{
+}
+
+LocklessCommandFifo::~LocklessCommandFifo()
+{
+}
+
+bool LocklessCommandFifo::init(uint32_t sizeInBytes)
+{
+    // Add room for a buffer reset command
+    mBuffer = static_cast<uint8_t *>(malloc(sizeInBytes + 4));
+    if (!mBuffer) {
+        LOGE("LocklessFifo allocation failure");
+        return false;
+    }
+
+    int status = pthread_mutex_init(&mMutex, NULL);
+    if (status) {
+        LOGE("LocklessFifo mutex init failure");
+        free(mBuffer);
+        return false;
+    }
+    status = pthread_cond_init(&mCondition, NULL);
+    if (status) {
+        LOGE("LocklessFifo condition init failure");
+        pthread_mutex_destroy(&mMutex);
+        free(mBuffer);
+        return false;
+    }
+
+    mSize = sizeInBytes;
+    mPut = mBuffer;
+    mGet = mBuffer;
+    mEnd = mBuffer + (sizeInBytes) - 1;
+    dumpState("init");
+    return true;
+}
+
+uint32_t LocklessCommandFifo::getFreeSpace() const 
+{
+    int32_t freeSpace = 0;
+    //dumpState("getFreeSpace");
+
+    if (mPut >= mGet) {
+        freeSpace = mEnd - mPut;
+    } else {
+        freeSpace = mGet - mPut;
+    }
+
+    if (freeSpace < 0) {
+        freeSpace = 0;
+    }
+    
+    //LOGE("free %i", freeSpace);
+    return freeSpace;
+}
+
+bool LocklessCommandFifo::isEmpty() const
+{
+    return mPut == mGet;
+}
+
+
+void * LocklessCommandFifo::reserve(uint32_t sizeInBytes)
+{
+    // Add space for command header and loop token;
+    sizeInBytes += 8;
+
+    //dumpState("reserve");
+    if (getFreeSpace() < sizeInBytes) {
+        makeSpace(sizeInBytes);
+    }
+
+    return mPut + 4;
+}
+
+void LocklessCommandFifo::commit(uint32_t command, uint32_t sizeInBytes)
+{
+    //LOGE("commit cmd %i  size %i", command, sizeInBytes);
+    //dumpState("commit 1");
+    reinterpret_cast<uint16_t *>(mPut)[0] = command;
+    reinterpret_cast<uint16_t *>(mPut)[1] = sizeInBytes;
+    mPut += ((sizeInBytes + 3) & ~3) + 4;
+    //dumpState("commit 2");
+
+}
+
+void LocklessCommandFifo::commitSync(uint32_t command, uint32_t sizeInBytes)
+{
+    commit(command, sizeInBytes);
+    flush();
+}
+
+void LocklessCommandFifo::flush()
+{
+    //dumpState("flush 1");
+    while(mPut != mGet) {
+        usleep(1);
+    }
+    //dumpState("flush 2");
+}
+
+const void * LocklessCommandFifo::get(uint32_t *command, uint32_t *bytesData)
+{
+    while(1) {
+        while(isEmpty()) {
+            usleep(10);
+        }
+        //dumpState("get 3");
+
+        *command = reinterpret_cast<const uint16_t *>(mGet)[0];
+        *bytesData = reinterpret_cast<const uint16_t *>(mGet)[1];
+        //LOGE("Got %i, %i", *command, *bytesData);
+    
+        if (*command) {
+            // non-zero command is valid
+            return mGet+4;
+        }
+    
+        // zero command means reset to beginning.
+        mGet = mBuffer;
+    }
+}
+
+void LocklessCommandFifo::next()
+{
+    uint32_t bytes = reinterpret_cast<const uint16_t *>(mGet)[1];
+    mGet += ((bytes + 3) & ~3) + 4;
+    //dumpState("next");
+}
+
+void LocklessCommandFifo::makeSpace(uint32_t bytes)
+{
+    //dumpState("make space");
+    if ((mPut+bytes) > mEnd) {
+        // Need to loop regardless of where get is.
+        while((mGet > mPut) && (mBuffer+4 >= mGet)) {
+            sleep(1);
+        }
+
+        // Toss in a reset then the normal wait for space will do the rest.
+        reinterpret_cast<uint16_t *>(mPut)[0] = 0;
+        reinterpret_cast<uint16_t *>(mPut)[1] = 0;
+        mPut = mBuffer;
+    }
+
+    // it will fit here so we just need to wait for space.
+    while(getFreeSpace() < bytes) {
+        sleep(1);
+    }
+    
+}
+
+void LocklessCommandFifo::dumpState(const char *s) const
+{
+    LOGE("%s  put %p, get %p,  buf %p,  end %p", s, mPut, mGet, mBuffer, mEnd);
+}
+
+