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/*
* 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 */
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