1 files changed, 85 insertions, 0 deletions
diff --git a/o3d/command_buffer/client/id_allocator.cc b/o3d/command_buffer/client/id_allocator.cc
new file mode 100644
index 0000000..fc3250d
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+++ b/o3d/command_buffer/client/id_allocator.cc
@@ -0,0 +1,85 @@
+/*
+ * Copyright 2009, Google Inc.
+ * All rights reserved.
+ *
+ * Redistribution and use in source and binary forms, with or without
+ * modification, are permitted provided that the following conditions are
+ * met:
+ *
+ *     * Redistributions of source code must retain the above copyright
+ * notice, this list of conditions and the following disclaimer.
+ *     * Redistributions in binary form must reproduce the above
+ * copyright notice, this list of conditions and the following disclaimer
+ * in the documentation and/or other materials provided with the
+ * distribution.
+ *     * Neither the name of Google Inc. nor the names of its
+ * contributors may be used to endorse or promote products derived from
+ * this software without specific prior written permission.
+ *
+ * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+ * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+ * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+ * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+ * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+ * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+ * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+ * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+ * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+ * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+ * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+ */
+
+
+// This file contains the implementation of IdAllocator.
+
+#include "command_buffer/client/id_allocator.h"
+
+namespace command_buffer {
+
+IdAllocator::IdAllocator() : bitmap_(1) { bitmap_[0] = 0; }
+
+static const unsigned int kBitsPerUint32 = sizeof(Uint32) * 8;  // NOLINT
+
+// Looks for the first non-full entry, and return the first free bit in that
+// entry. If all the entries are full, it will return the first bit of an entry
+// that would be appended, but doesn't actually append that entry to the vector.
+unsigned int IdAllocator::FindFirstFree() const {
+  size_t size = bitmap_.size();
+  for (unsigned int i = 0; i < size; ++i) {
+    Uint32 value = bitmap_[i];
+    if (value != 0xffffffffU) {
+      for (unsigned int j = 0; j < kBitsPerUint32; ++j) {
+        if (!(value & (1 << j))) return i * kBitsPerUint32 + j;
+      }
+      DLOG(FATAL) << "Code should not reach here.";
+    }
+  }
+  return size*kBitsPerUint32;
+}
+
+// Sets the correct bit in the proper entry, resizing the vector if needed.
+void IdAllocator::SetBit(unsigned int bit, bool value) {
+  size_t size = bitmap_.size();
+  if (bit >= size * kBitsPerUint32) {
+    size_t newsize = bit / kBitsPerUint32 + 1;
+    bitmap_.resize(newsize);
+    for (size_t i = size; i < newsize; ++i) bitmap_[i] = 0;
+  }
+  Uint32 mask = 1U << (bit % kBitsPerUint32);
+  if (value) {
+    bitmap_[bit / kBitsPerUint32] |= mask;
+  } else {
+    bitmap_[bit / kBitsPerUint32] &= ~mask;
+  }
+}
+
+// Gets the bit from the proper entry. This doesn't resize the vector, just
+// returns false if the bit is beyond the last entry.
+bool IdAllocator::GetBit(unsigned int bit) const {
+  size_t size = bitmap_.size();
+  if (bit / kBitsPerUint32 >= size) return false;
+  Uint32 mask = 1U << (bit % kBitsPerUint32);
+  return (bitmap_[bit / kBitsPerUint32] & mask) != 0;
+}
+
+}  // namespace command_buffer