A MemoryView structure, rb_memory_view_t, is used for exporting objects' MemoryView. More...

#include <memory_view.h>

Data Fields
VALUE	obj
	The original object that has the memory exported via this memory view. More...

void *	data
	The pointer to the exported memory. More...

ssize_t	byte_size
	The number of bytes in data. More...

bool	readonly
	true for readonly memory, false for writable memory. More...

const char *	format
	A string to describe the format of an element, or NULL for unsigned bytes. More...

ssize_t	item_size
	The number of bytes in each element. More...

struct {
const rb_memory_view_item_component_t * components
	The array of rb_memory_view_item_component_t that describes the item structure. More...

size_t length
	The number of components in an item. More...

}	item_desc
	Description of each components. More...

ssize_t	ndim
	The number of dimension. More...

const ssize_t *	shape
	ndim size array indicating the number of elements in each dimension. More...

const ssize_t *	strides
	ndim size array indicating the number of bytes to skip to go to the next element in each dimension. More...

const ssize_t *	sub_offsets
	The offset in each dimension when this memory view exposes a nested array. More...

void *	private_data
	The private data for managing this exported memory. More...

const struct rb_memory_view_entry *	_memory_view_entry
	DO NOT TOUCH THIS: The memory view entry for the internal use. More...

Detailed Description

A MemoryView structure, rb_memory_view_t, is used for exporting objects' MemoryView.

This structure contains the reference of the object, which is the owner of the MemoryView, the pointer to the head of exported memory, and the metadata that describes the structure of the memory. The metadata can describe multidimensional arrays with strides.

Definition at line 77 of file memory_view.h.

Field Documentation

◆ _memory_view_entry

const struct rb_memory_view_entry* rb_memory_view_t::_memory_view_entry

DO NOT TOUCH THIS: The memory view entry for the internal use.

Definition at line 153 of file memory_view.h.

Referenced by rb_memory_view_get(), and rb_memory_view_release().

◆ byte_size

ssize_t rb_memory_view_t::byte_size

The number of bytes in data.

Definition at line 87 of file memory_view.h.

Referenced by rb_memory_view_init_as_byte_array().

◆ components

const rb_memory_view_item_component_t* rb_memory_view_t::components

The array of rb_memory_view_item_component_t that describes the item structure.

rb_memory_view_prepare_item_desc and rb_memory_view_get_item allocate this memory if needed, and rb_memory_view_release frees it.

Definition at line 125 of file memory_view.h.

Referenced by rb_memory_view_get_item(), rb_memory_view_init_as_byte_array(), rb_memory_view_prepare_item_desc(), and rb_memory_view_release().

◆ data

void* rb_memory_view_t::data

The pointer to the exported memory.

Definition at line 84 of file memory_view.h.

Referenced by rb_memory_view_get_item_pointer(), and rb_memory_view_init_as_byte_array().

◆ format

const char* rb_memory_view_t::format

A string to describe the format of an element, or NULL for unsigned bytes.

The format string is a sequence of the following pack-template specifiers:

c, C, s, s!, S, S!, n, v, i, i!, I, I!, l, l!, L, L!, N, V, f, e, g, q, q!, Q, Q!, d, E, G, j, J, x

For example, "dd" for an element that consists of two double values, and "CCC" for an element that consists of three bytes, such as an RGB color triplet.

Also, the value endianness can be explicitly specified by '<' or '>' following a value type specifier.

The items are packed contiguously. When you emulate the alignment of structure members, put '|' at the beginning of the format string, like "|iqc". On x86_64 Linux ABI, the size of the item by this format is 24 bytes instead of 13 bytes.

Definition at line 111 of file memory_view.h.

Referenced by rb_memory_view_get_item(), rb_memory_view_init_as_byte_array(), and rb_memory_view_prepare_item_desc().