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Dynamic buffer requirements (version 2)

A dynamic buffer encapsulates memory storage that may be automatically resized as required.

A dynamic buffer type X shall satisfy the requirements of CopyConstructible (C++ Std, [copyconstructible]) types in addition to those listed below.

In the table below, X denotes a dynamic buffer class, x denotes a value of type X&, x1 denotes values of type const X&, pos and n denote values of type size_t, and u denotes an identifier.

Table 12. DynamicBuffer_v2 requirements

expression

type

assertion/note
pre/post-conditions

X::const_buffers_type

type meeting ConstBufferSequence requirements.

This type represents the underlying memory as a sequence of @c const_buffer objects.

X::mutable_buffers_type

type meeting MutableBufferSequence requirements.

This type represents the underlying memory as a sequence of @c mutable_buffer objects.

x1.size()

size_t

Returns the size, in bytes, of the underlying memory.

x1.max_size()

size_t

Returns the permitted maximum size of the underlying memory.

x1.capacity()

size_t

Returns the maximum size to which the underlying memory can grow without requiring reallocation.

x1.data(pos, n)

X::const_buffers_type

Returns a constant buffer sequence u that represents the underlying memory beginning at offset pos, and where buffer_size(u) <= n.

x.data(pos, n)

X::mutable_buffers_type

Returns a mutable buffer sequence u that represents the underlying memory beginning at offset pos, and where buffer_size(u) <= n.

x.grow(n)

Requires: size() + n <= max_size().

Extends the underlying memory to accommodate n additional bytes at the end. The dynamic buffer reallocates memory as required. All constant or mutable buffer sequences previously obtained using data() are invalidated.

Throws: length_error if size() + n > max_size().

x.shrink(n)

Removes n bytes from the end of the underlying memory. If n is greater than the size of the underlying memory, the entire underlying memory is emptied. All constant or mutable buffer sequences previously obtained using data() are invalidated.

x.consume(n)

Removes n bytes from the beginning of the underlying memory. If n is greater than the size of the underlying memory, the entire underlying memory is emptied. All constant or mutable buffer sequences previously obtained using data() are invalidated.



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