Initial community commit

Src/external_dependencies/openmpt-trunk/src/mpt/base/aligned_array.hpp

@@ -0,0 +1,99 @@
+/* SPDX-License-Identifier: BSL-1.0 OR BSD-3-Clause */
+
+#ifndef MPT_BASE_ALIGNED_ARRAY_HPP
+#define MPT_BASE_ALIGNED_ARRAY_HPP
+
+
+
+#include "mpt/base/bit.hpp"
+#include "mpt/base/namespace.hpp"
+
+#include <array>
+#include <memory>
+#include <new>
+
+#include <cassert>
+#include <cstddef>
+
+
+
+namespace mpt {
+inline namespace MPT_INLINE_NS {
+
+
+template <typename T, std::size_t count, std::align_val_t alignment>
+struct alignas(static_cast<std::size_t>(alignment)) aligned_array
+	: std::array<T, count> {
+	static_assert(static_cast<std::size_t>(alignment) >= alignof(T));
+	static_assert(((count * sizeof(T)) % static_cast<std::size_t>(alignment)) == 0);
+	static_assert(sizeof(std::array<T, count>) == (sizeof(T) * count));
+};
+
+static_assert(sizeof(mpt::aligned_array<float, 4, std::align_val_t{sizeof(float) * 4}>) == sizeof(std::array<float, 4>));
+
+
+
+template <std::size_t alignment_elements, std::size_t expected_elements, typename T, std::size_t N>
+T * align_elements(std::array<T, N> & a) {
+	static_assert(mpt::has_single_bit(alignof(T)));
+	static_assert(mpt::has_single_bit(sizeof(T)));
+	static_assert(mpt::has_single_bit(alignment_elements));
+	static_assert((expected_elements + alignment_elements - 1) <= N);
+	void * buf = a.data();
+	std::size_t size = N * sizeof(T);
+	void * result = std::align(alignment_elements * sizeof(T), expected_elements * sizeof(T), buf, size);
+	assert(result);
+	return reinterpret_cast<T *>(result);
+}
+
+template <std::size_t alignment_elements, std::size_t expected_elements, typename T, std::size_t N>
+T * align_elements(T (&a)[N]) {
+	static_assert(mpt::has_single_bit(alignof(T)));
+	static_assert(mpt::has_single_bit(sizeof(T)));
+	static_assert(mpt::has_single_bit(alignment_elements));
+	static_assert((expected_elements + alignment_elements - 1) <= N);
+	void * buf = a;
+	std::size_t size = N * sizeof(T);
+	void * result = std::align(alignment_elements * sizeof(T), expected_elements * sizeof(T), buf, size);
+	assert(result);
+	return reinterpret_cast<T *>(result);
+}
+
+
+
+template <std::size_t alignment_bytes, std::size_t expected_elements, typename T, std::size_t N>
+T * align_bytes(std::array<T, N> & a) {
+	static_assert(mpt::has_single_bit(alignof(T)));
+	static_assert(mpt::has_single_bit(sizeof(T)));
+	static_assert(mpt::has_single_bit(alignment_bytes));
+	static_assert((alignment_bytes % alignof(T)) == 0);
+	static_assert(((expected_elements * sizeof(T)) + alignment_bytes - 1) <= (N * sizeof(T)));
+	void * buf = a.data();
+	std::size_t size = N * sizeof(T);
+	void * result = std::align(alignment_bytes, expected_elements * sizeof(T), buf, size);
+	assert(result);
+	return reinterpret_cast<T *>(result);
+}
+
+template <std::size_t alignment_bytes, std::size_t expected_elements, typename T, std::size_t N>
+T * align_bytes(T (&a)[N]) {
+	static_assert(mpt::has_single_bit(alignof(T)));
+	static_assert(mpt::has_single_bit(sizeof(T)));
+	static_assert(mpt::has_single_bit(alignment_bytes));
+	static_assert((alignment_bytes % alignof(T)) == 0);
+	static_assert(((expected_elements * sizeof(T)) + alignment_bytes - 1) <= (N * sizeof(T)));
+	void * buf = a;
+	std::size_t size = N * sizeof(T);
+	void * result = std::align(alignment_bytes, expected_elements * sizeof(T), buf, size);
+	assert(result);
+	return reinterpret_cast<T *>(result);
+}
+
+
+
+} // namespace MPT_INLINE_NS
+} // namespace mpt
+
+
+
+#endif // MPT_BASE_ALIGNED_ARRAY_HPP