1 files changed, 215 insertions, 0 deletions
diff --git a/media/libcubeb/src/cubeb_utils.h b/media/libcubeb/src/cubeb_utils.h
new file mode 100644
index 000000000..d8e9928fe
--- /dev/null
+++ b/media/libcubeb/src/cubeb_utils.h
@@ -0,0 +1,215 @@
+/*
+ * Copyright © 2016 Mozilla Foundation
+ *
+ * This program is made available under an ISC-style license.  See the
+ * accompanying file LICENSE for details.
+ */
+
+#if !defined(CUBEB_UTILS)
+#define CUBEB_UTILS
+
+#include <stdint.h>
+#include <string.h>
+#include <assert.h>
+#include <type_traits>
+#if defined(WIN32)
+#include "cubeb_utils_win.h"
+#else
+#include "cubeb_utils_unix.h"
+#endif
+
+/** Similar to memcpy, but accounts for the size of an element. */
+template<typename T>
+void PodCopy(T * destination, const T * source, size_t count)
+{
+  static_assert(std::is_trivial<T>::value, "Requires trivial type");
+  memcpy(destination, source, count * sizeof(T));
+}
+
+/** Similar to memmove, but accounts for the size of an element. */
+template<typename T>
+void PodMove(T * destination, const T * source, size_t count)
+{
+  static_assert(std::is_trivial<T>::value, "Requires trivial type");
+  memmove(destination, source, count * sizeof(T));
+}
+
+/** Similar to a memset to zero, but accounts for the size of an element. */
+template<typename T>
+void PodZero(T * destination, size_t count)
+{
+  static_assert(std::is_trivial<T>::value, "Requires trivial type");
+  memset(destination, 0,  count * sizeof(T));
+}
+
+template<typename T>
+class auto_array
+{
+public:
+  explicit auto_array(uint32_t capacity = 0)
+    : data_(capacity ? new T[capacity] : nullptr)
+    , capacity_(capacity)
+    , length_(0)
+  {}
+
+  ~auto_array()
+  {
+    delete [] data_;
+  }
+
+  /** Get a constant pointer to the underlying data. */
+  T * data() const
+  {
+    return data_;
+  }
+
+  const T& at(size_t index) const
+  {
+    assert(index < length_ && "out of range");
+    return data_[index];
+  }
+
+  T& at(size_t index)
+  {
+    assert(index < length_ && "out of range");
+    return data_[index];
+  }
+
+  /** Get how much underlying storage this auto_array has. */
+  size_t capacity() const
+  {
+    return capacity_;
+  }
+
+  /** Get how much elements this auto_array contains. */
+  size_t length() const
+  {
+    return length_;
+  }
+
+  /** Keeps the storage, but removes all the elements from the array. */
+  void clear()
+  {
+    length_ = 0;
+  }
+
+   /** Change the storage of this auto array, copying the elements to the new
+    * storage.
+    * @returns true in case of success
+    * @returns false if the new capacity is not big enough to accomodate for the
+    *                elements in the array.
+    */
+  bool reserve(size_t new_capacity)
+  {
+    if (new_capacity < length_) {
+      return false;
+    }
+    T * new_data = new T[new_capacity];
+    if (data_ && length_) {
+      PodCopy(new_data, data_, length_);
+    }
+    capacity_ = new_capacity;
+    delete [] data_;
+    data_ = new_data;
+
+    return true;
+  }
+
+   /** Append `length` elements to the end of the array, resizing the array if
+    * needed.
+    * @parameter elements the elements to append to the array.
+    * @parameter length the number of elements to append to the array.
+    */
+  void push(const T * elements, size_t length)
+  {
+    if (length_ + length > capacity_) {
+      reserve(length_ + length);
+    }
+    PodCopy(data_ + length_, elements, length);
+    length_ += length;
+  }
+
+  /** Append `length` zero-ed elements to the end of the array, resizing the
+   * array if needed.
+   * @parameter length the number of elements to append to the array.
+   */
+  void push_silence(size_t length)
+  {
+    if (length_ + length > capacity_) {
+      reserve(length + length_);
+    }
+    PodZero(data_ + length_, length);
+    length_ += length;
+  }
+
+  /** Prepend `length` zero-ed elements to the end of the array, resizing the
+   * array if needed.
+   * @parameter length the number of elements to prepend to the array.
+   */
+  void push_front_silence(size_t length)
+  {
+    if (length_ + length > capacity_) {
+      reserve(length + length_);
+    }
+    PodMove(data_ + length, data_, length_);
+    PodZero(data_, length);
+    length_ += length;
+  }
+
+  /** Return the number of free elements in the array. */
+  size_t available() const
+  {
+    return capacity_ - length_;
+  }
+
+  /** Copies `length` elements to `elements` if it is not null, and shift
+    * the remaining elements of the `auto_array` to the beginning.
+    * @parameter elements a buffer to copy the elements to, or nullptr.
+    * @parameter length the number of elements to copy.
+    * @returns true in case of success.
+    * @returns false if the auto_array contains less than `length` elements. */
+  bool pop(T * elements, size_t length)
+  {
+    if (length > length_) {
+      return false;
+    }
+    if (elements) {
+      PodCopy(elements, data_, length);
+    }
+    PodMove(data_, data_ + length, length_ - length);
+
+    length_ -= length;
+
+    return true;
+  }
+
+  void set_length(size_t length)
+  {
+    assert(length <= capacity_);
+    length_ = length;
+  }
+
+private:
+  /** The underlying storage */
+  T * data_;
+  /** The size, in number of elements, of the storage. */
+  size_t capacity_;
+  /** The number of elements the array contains. */
+  size_t length_;
+};
+
+struct auto_lock {
+  explicit auto_lock(owned_critical_section & lock)
+    : lock(lock)
+  {
+    lock.enter();
+  }
+  ~auto_lock()
+  {
+    lock.leave();
+  }
+private:
+  owned_critical_section & lock;
+};
+
+#endif /* CUBEB_UTILS */