diff options
| -rw-r--r-- | src/util/WritableBuffer.hxx | 31 |
1 files changed, 30 insertions, 1 deletions
diff --git a/src/util/WritableBuffer.hxx b/src/util/WritableBuffer.hxx index 1b37b56cb..7267813f5 100644 --- a/src/util/WritableBuffer.hxx +++ b/src/util/WritableBuffer.hxx @@ -32,7 +32,11 @@ #include "Compiler.h" -#include <stddef.h> +#include <cstddef> + +#ifndef NDEBUG +#include <assert.h> +#endif /** * A reference to a memory area that is writable. @@ -52,6 +56,8 @@ struct WritableBuffer { WritableBuffer() = default; + constexpr WritableBuffer(std::nullptr_t):data(nullptr), size(0) {} + constexpr WritableBuffer(pointer_type _data, size_type _size) :data(_data), size(_size) {} @@ -59,6 +65,29 @@ struct WritableBuffer { 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 WritableBuffer<void> ToVoid() const { + static_assert(sizeof(T) > 0, "Empty base type"); + return WritableBuffer<void>(data, size * sizeof(T)); + } + constexpr bool IsNull() const { return data == nullptr; } |