Threadsafe bitmap class

src/xenia/base/bit_map.h

@@ -0,0 +1,56 @@
+/**
+ ******************************************************************************
+ * Xenia : Xbox 360 Emulator Research Project                                 *
+ ******************************************************************************
+ * Copyright 2015 Ben Vanik. All rights reserved.                             *
+ * Released under the BSD license - see LICENSE in the root for more details. *
+ ******************************************************************************
+ */
+
+#ifndef XENIA_BASE_BIT_MAP_H_
+#define XENIA_BASE_BIT_MAP_H_
+
+#include <cstdint>
+#include <vector>
+
+namespace xe {
+
+// Bit Map: Efficient lookup of free/used entries.
+class BitMap {
+ public:
+  BitMap();
+
+  // Size is the number of 8-bit entries, must be a multiple of 4.
+  BitMap(size_t size);
+
+  // Data does not have to be aligned to a 4-byte boundary, but it is
+  // preferable.
+  // Size is the number of 8-bit entries, must be a multiple of 4.
+  BitMap(uint32_t* data, size_t size);
+
+  // (threadsafe) Acquires an entry and returns its index. Returns -1 if there
+  // are no more free entries.
+  size_t Acquire();
+
+  // (threadsafe) Releases an entry by an index.
+  void Release(size_t index);
+
+  // Resize the bitmap. Size is the number of 8-bit entries, must be a multiple
+  // of 4.
+  void Resize(size_t new_size);
+
+  // Sets all entries to free.
+  void Reset();
+
+  const std::vector<uint32_t> data() const { return data_; }
+  std::vector<uint32_t>& data() { return data_; }
+
+ private:
+  const static uint32_t kDataSize = 4;
+  const static uint32_t kDataSizeBits = kDataSize * 8;
+  std::vector<uint32_t> data_;
+};
+
+}  // namespace xe
+
+#endif  // XENIA_BASE_BIT_MAP_H_