diff options
Diffstat (limited to 'src/util/WritableBuffer.hxx')
-rw-r--r-- | src/util/WritableBuffer.hxx | 138 |
1 files changed, 106 insertions, 32 deletions
diff --git a/src/util/WritableBuffer.hxx b/src/util/WritableBuffer.hxx index 4e529cfad..d13f80867 100644 --- a/src/util/WritableBuffer.hxx +++ b/src/util/WritableBuffer.hxx @@ -32,7 +32,45 @@ #include "Compiler.h" -#include <stddef.h> +#include <cstddef> + +#ifndef NDEBUG +#include <assert.h> +#endif + +template<typename T> +struct WritableBuffer; + +template<> +struct WritableBuffer<void> { + typedef size_t size_type; + typedef void *pointer_type; + typedef const void *const_pointer_type; + typedef pointer_type iterator; + typedef const_pointer_type const_iterator; + + pointer_type data; + size_type size; + + WritableBuffer() = default; + + constexpr WritableBuffer(std::nullptr_t):data(nullptr), size(0) {} + + constexpr WritableBuffer(pointer_type _data, size_type _size) + :data(_data), size(_size) {} + + constexpr static WritableBuffer Null() { + return { nullptr, 0 }; + } + + constexpr bool IsNull() const { + return data == nullptr; + } + + constexpr bool IsEmpty() const { + return size == 0; + } +}; /** * A reference to a memory area that is writable. @@ -41,47 +79,83 @@ */ template<typename T> struct WritableBuffer { - typedef size_t size_type; - typedef T *pointer_type; - typedef const T *const_pointer_type; - typedef pointer_type iterator; - typedef const_pointer_type const_iterator; + typedef size_t size_type; + typedef T *pointer_type; + typedef const T *const_pointer_type; + typedef pointer_type iterator; + typedef const_pointer_type const_iterator; + + pointer_type data; + size_type size; - pointer_type data; - size_type size; + WritableBuffer() = default; - WritableBuffer() = default; + constexpr WritableBuffer(std::nullptr_t):data(nullptr), size(0) {} - constexpr WritableBuffer(pointer_type _data, size_type _size) - :data(_data), size(_size) {} + constexpr WritableBuffer(pointer_type _data, size_type _size) + :data(_data), size(_size) {} - constexpr static WritableBuffer Null() { - return { nullptr, 0 }; - } + constexpr static WritableBuffer Null() { + return { nullptr, 0 }; + } + + /** + * Cast a WritableBuffer<void> to a WritableBuffer<T>. A "void" + * buffer records its size in bytes, and when casting to "T", + * the assertion below ensures that the size is a multiple of + * sizeof(T). + */ +#ifdef NDEBUG + constexpr +#endif + static WritableBuffer<T> FromVoid(WritableBuffer<void> other) { + static_assert(sizeof(T) > 0, "Empty base type"); +#ifndef NDEBUG + assert(other.size % sizeof(T) == 0); +#endif + return WritableBuffer<T>(pointer_type(other.data), + other.size / sizeof(T)); + } - constexpr bool IsNull() const { - return data == nullptr; - } + constexpr WritableBuffer<void> ToVoid() const { + static_assert(sizeof(T) > 0, "Empty base type"); + return WritableBuffer<void>(data, size * sizeof(T)); + } - constexpr bool IsEmpty() const { - return size == 0; - } + constexpr bool IsNull() const { + return data == nullptr; + } - constexpr iterator begin() const { - return data; - } + constexpr bool IsEmpty() const { + return size == 0; + } - constexpr iterator end() const { - return data + size; - } + constexpr iterator begin() const { + return data; + } - constexpr const_iterator cbegin() const { - return data; - } + constexpr iterator end() const { + return data + size; + } + + constexpr const_iterator cbegin() const { + return data; + } + + constexpr const_iterator cend() const { + return data + size; + } + +#ifdef NDEBUG + constexpr +#endif + T &operator[](size_type i) const { +#ifndef NDEBUG + assert(i < size); +#endif - constexpr const_iterator cend() const { - return data + size; - } + return data[i]; + } }; #endif |