Squashed 'tmk_core/' changes from 7967731..b9e0ea0

b9e0ea0 Merge commit '7fa9d8bdea3773d1195b04d98fcf27cf48ddd81d' as 'tool/mbed/mbed-sdk'
7fa9d8b Squashed 'tool/mbed/mbed-sdk/' content from commit 7c21ce5

git-subtree-dir: tmk_core
git-subtree-split: b9e0ea08cb940de20b3610ecdda18e9d8cd7c552

tool/mbed/mbed-sdk/libraries/USBHost/USBHostSerial/MtxCircBuffer.h

@@ -0,0 +1,89 @@
+/* mbed USBHost Library
+ * Copyright (c) 2006-2013 ARM Limited
+ *
+ * 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.
+ */
+
+#ifndef MTXCIRCBUFFER_H
+#define MTXCIRCBUFFER_H
+
+#include "stdint.h"
+#include "rtos.h"
+
+//Mutex protected circular buffer
+template<typename T, int size>
+class MtxCircBuffer {
+public:
+
+    MtxCircBuffer() {
+        write = 0;
+        read = 0;
+    }
+
+    bool isFull() {
+        mtx.lock();
+        bool r = (((write + 1) % size) == read);
+        mtx.unlock();
+        return r;
+    }
+
+    bool isEmpty() {
+        mtx.lock();
+        bool r = (read == write);
+        mtx.unlock();
+        return r;
+    }
+
+    void flush() {
+        write = 0;
+        read = 0;
+    }
+
+    void queue(T k) {
+        mtx.lock();
+        while (((write + 1) % size) == read) {
+            mtx.unlock();
+            Thread::wait(10);
+            mtx.lock();
+        }
+        buf[write++] = k;
+        write %= size;
+        mtx.unlock();
+    }
+
+    uint16_t available() {
+        mtx.lock();
+        uint16_t a = (write >= read) ? (write - read) : (size - read + write);
+        mtx.unlock();
+        return a;
+    }
+
+    bool dequeue(T * c) {
+        mtx.lock();
+        bool empty = (read == write);
+        if (!empty) {
+            *c = buf[read++];
+            read %= size;
+        }
+        mtx.unlock();
+        return (!empty);
+    }
+
+private:
+    volatile uint16_t write;
+    volatile uint16_t read;
+    volatile T buf[size];
+    Mutex mtx;
+};
+
+#endif