OEMCrypto Profiler

This CL is a merge from the widevine repo of:
http://go/wvgerrit/16491 Circular Buffer
http://go/wvgerrit/16512 Circular Buffer Tests
http://go/wvgerrit/16493 Entry Writer
http://go/wvgerrit/16495 Profiled Scope
http://go/wvgerrit/16500 Stats Collection
http://go/wvgerrit/16543 Disallow Stats Copy or Assign
http://go/wvgerrit/16514 Moving OEM Function Enum
http://go/wvgerrit/16501 Defining Session Interface
http://go/wvgerrit/16502 Session Definitions
http://go/wvgerrit/16573 Remove code to num bytes table
http://go/wvgerrit/16556 Connecting Profiler to Profiled Scope
http://go/wvgerrit/16557 Android Reading Profiler History
http://go/wvgerrit/16574 Adding Get Stats Method
http://go/wvgerrit/16606 Seperating Session Parsing
http://go/wvgerrit/16607 Adding get stats method to DRMPlugin
http://go/wvgerrit/16608 Fixing Linux Build Failure
http://go/wvgerrit/16612 Stop Clearing History
http://go/wvgerrit/16613 Accessing profiler information using session id
http://go/wvgerrit/16614 Making All Session Subsets of Global Session

BUG: 25123303
BUG: 26027857
Change-Id: Ie2422e644aa631871852ea0e461695aeb7060f88

libwvdrmengine/cdm/profiler/include/circular_buffer.h

@@ -0,0 +1,62 @@
+// Copyright 2016 Google Inc. All Rights Reserved.
+
+#ifndef WVCDM_PROFILER_CIRCULAR_BUFFER_H_
+#define WVCDM_PROFILER_CIRCULAR_BUFFER_H_
+
+#include <stddef.h>
+#include <stdint.h>
+#include <vector>
+
+namespace wvcdm {
+namespace oemprofiler {
+
+class CircularBuffer {
+ public:
+  explicit CircularBuffer(size_t memoryBudget);
+
+  size_t GetFreeSpace() const;
+
+  size_t GetUsedSpace() const;
+
+  // Add a series of bytes to the buffer. Values will remain in
+  // the buffer until Remove removes them. If there is not enough
+  // room for the full series, no bytes are written into the buffer.
+  bool AddU8s(const uint8_t* values, size_t numValues);
+
+  // Add a single byte to the buffer. The value will remain in the
+  // buffer until Remove removes it. If the buffer is full, the
+  // byte will not be written into the buffer.
+  bool AddU8(uint8_t value);
+
+  // Read a series of bytes without removing them. The start of the
+  // read is from the end (the oldest entry) + offset (toward the newest
+  // entry). If requested number of bytes is too large, no bytes are read
+  // and the function returns false.
+  bool PeekU8s(size_t offset, uint8_t* out, size_t numToRead) const;
+
+  // Read a single byte without removing it. The read byte is at the index
+  // of the oldest entry + offset (toward the newest entry). If there are
+  // no bytes in the buffer the function returns false.
+  bool PeekU8(size_t offset, uint8_t* out) const;
+
+  // Remove the requested number of bytes from the buffer from oldest
+  // to newest. If there are not enough bytes to remove, nothing is
+  // removed and the function returns false.
+  bool Remove(size_t numBytes);
+
+ private:
+  std::vector<uint8_t> buffer_;
+
+  size_t fill_;
+  size_t head_;
+  size_t tail_;
+
+  // disallow copy and assign
+  CircularBuffer(const CircularBuffer&);
+  void operator=(const CircularBuffer&);
+};
+
+}  // namespace oemprofiler
+}  // namespace wvcdm
+
+#endif