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#ifndef RUBY_MEMORY_VIEW_H /*-*-C++-*-vi:se ft=cpp:*/
#define RUBY_MEMORY_VIEW_H 1
/**
* @file
* @author Ruby developers <ruby-core@ruby-lang.org>
* @copyright This file is a part of the programming language Ruby.
* Permission is hereby granted, to either redistribute and/or
* modify this file, provided that the conditions mentioned in the
* file COPYING are met. Consult the file for details.
* @brief Memory View.
*/
#include "ruby/internal/config.h"
#ifdef STDC_HEADERS
# include <stddef.h> /* size_t */
#endif
#if HAVE_SYS_TYPES_H
# include <sys/types.h> /* ssize_t */
#endif
#include "ruby/internal/attr/pure.h" /* RBIMPL_ATTR_PURE */
#include "ruby/internal/core/rtypeddata.h" /* rb_data_type_t */
#include "ruby/internal/dllexport.h" /* RUBY_EXTERN */
#include "ruby/internal/stdbool.h" /* bool */
#include "ruby/internal/value.h" /* VALUE */
/**
* Flags passed to rb_memory_view_get(), then to ::rb_memory_view_get_func_t.
*/
enum ruby_memory_view_flags {
RUBY_MEMORY_VIEW_SIMPLE = 0,
RUBY_MEMORY_VIEW_WRITABLE = (1<<0),
RUBY_MEMORY_VIEW_FORMAT = (1<<1),
RUBY_MEMORY_VIEW_MULTI_DIMENSIONAL = (1<<2),
RUBY_MEMORY_VIEW_STRIDES = (1<<3) | RUBY_MEMORY_VIEW_MULTI_DIMENSIONAL,
RUBY_MEMORY_VIEW_ROW_MAJOR = (1<<4) | RUBY_MEMORY_VIEW_STRIDES,
RUBY_MEMORY_VIEW_COLUMN_MAJOR = (1<<5) | RUBY_MEMORY_VIEW_STRIDES,
RUBY_MEMORY_VIEW_ANY_CONTIGUOUS = RUBY_MEMORY_VIEW_ROW_MAJOR | RUBY_MEMORY_VIEW_COLUMN_MAJOR,
RUBY_MEMORY_VIEW_INDIRECT = (1<<6) | RUBY_MEMORY_VIEW_STRIDES,
};
/** Memory view component metadata. */
typedef struct {
/** @see ::rb_memory_view_t::format */
char format;
/** :FIXME: what is a "native" size is unclear. */
unsigned native_size_p: 1;
/** Endian of the component */
unsigned little_endian_p: 1;
/** The component's offset. */
size_t offset;
/** The component's size. */
size_t size;
/**
* How many numbers of components are there. For instance "CCC"'s repeat is
* 3.
*/
size_t repeat;
} rb_memory_view_item_component_t;
/**
* 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.
*/
typedef struct {
/**
* The original object that has the memory exported via this memory view.
*/
VALUE obj;
/** The pointer to the exported memory. */
void *data;
/** The number of bytes in data. */
ssize_t byte_size;
/** true for readonly memory, false for writable memory. */
bool readonly;
/**
* 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.
*/
const char *format;
/**
* The number of bytes in each element.
* item_size should equal to rb_memory_view_item_size_from_format(format). */
ssize_t item_size;
/** Description of each components. */
struct {
/**
* 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. */
const rb_memory_view_item_component_t *components;
/** The number of components in an item. */
size_t length;
} item_desc;
/** The number of dimension. */
ssize_t ndim;
/**
* ndim size array indicating the number of elements in each dimension.
* This can be NULL when ndim == 1. */
const ssize_t *shape;
/**
* ndim size array indicating the number of bytes to skip to go to the
* next element in each dimension. */
const ssize_t *strides;
/**
* The offset in each dimension when this memory view exposes a nested array.
* Or, NULL when this memory view exposes a flat array. */
const ssize_t *sub_offsets;
/** The private data for managing this exported memory */
void *private_data;
/** DO NOT TOUCH THIS: The memory view entry for the internal use */
const struct rb_memory_view_entry *_memory_view_entry;
} rb_memory_view_t;
/** Type of function of ::rb_memory_view_entry_t::get_func. */
typedef bool (* rb_memory_view_get_func_t)(VALUE obj, rb_memory_view_t *view, int flags);
/** Type of function of ::rb_memory_view_entry_t::release_func. */
typedef bool (* rb_memory_view_release_func_t)(VALUE obj, rb_memory_view_t *view);
/** Type of function of ::rb_memory_view_entry_t::available_p_func. */
typedef bool (* rb_memory_view_available_p_func_t)(VALUE obj);
/** Operations applied to a specific kind of a memory view. */
typedef struct rb_memory_view_entry {
/**
* Exports a memory view from a Ruby object.
*/
rb_memory_view_get_func_t get_func;
/**
* Releases a memory view that was previously generated using
* ::rb_memory_view_entry_t::get_func.
*/
rb_memory_view_release_func_t release_func;
/**
* Queries if an object understands memory view protocol.
*/
rb_memory_view_available_p_func_t available_p_func;
} rb_memory_view_entry_t;
RBIMPL_SYMBOL_EXPORT_BEGIN()
/* memory_view.c */
/**
* Associates the passed class with the passed memory view entry. This has to
* be called before actually creating a memory view from an instance.
*/
bool rb_memory_view_register(VALUE klass, const rb_memory_view_entry_t *entry);
RBIMPL_ATTR_PURE()
/**
* Return `true` if the data in the MemoryView `view` is row-major contiguous.
*
* Return `false` otherwise.
*/
bool rb_memory_view_is_row_major_contiguous(const rb_memory_view_t *view);
RBIMPL_ATTR_PURE()
/**
* Return `true` if the data in the MemoryView `view` is column-major
* contiguous.
*
* Return `false` otherwise.
*/
bool rb_memory_view_is_column_major_contiguous(const rb_memory_view_t *view);
RBIMPL_ATTR_NOALIAS()
/**
* Fill the `strides` array with byte-Strides of a contiguous array of the
* given shape with the given element size.
*/
void rb_memory_view_fill_contiguous_strides(const ssize_t ndim, const ssize_t item_size, const ssize_t *const shape, const bool row_major_p, ssize_t *const strides);
RBIMPL_ATTR_NOALIAS()
/**
* Fill the members of `view` as an 1-dimensional byte array.
*/
bool rb_memory_view_init_as_byte_array(rb_memory_view_t *view, VALUE obj, void *data, const ssize_t len, const bool readonly);
/**
* Deconstructs the passed format string, as describe in
* ::rb_memory_view_t::format.
*/
ssize_t rb_memory_view_parse_item_format(const char *format,
rb_memory_view_item_component_t **members,
size_t *n_members, const char **err);
/**
* Calculate the number of bytes occupied by an element.
*
* When the calculation fails, the failed location in `format` is stored into
* `err`, and returns `-1`.
*/
ssize_t rb_memory_view_item_size_from_format(const char *format, const char **err);
/**
* Calculate the location of the item indicated by the given `indices`.
*
* The length of `indices` must equal to `view->ndim`.
*
* This function initializes `view->item_desc` if needed.
*/
void *rb_memory_view_get_item_pointer(rb_memory_view_t *view, const ssize_t *indices);
/**
* Return a value that consists of item members.
*
* When an item is a single member, the return value is a single value.
*
* When an item consists of multiple members, an array will be returned.
*/
VALUE rb_memory_view_extract_item_members(const void *ptr, const rb_memory_view_item_component_t *members, const size_t n_members);
/** Fill the `item_desc` member of `view`. */
void rb_memory_view_prepare_item_desc(rb_memory_view_t *view);
/** * Return a value that consists of item members in the given memory view. */
VALUE rb_memory_view_get_item(rb_memory_view_t *view, const ssize_t *indices);
/**
* Return `true` if `obj` supports to export a MemoryView. Return `false`
* otherwise.
*
* If this function returns `true`, it doesn't mean the function
* `rb_memory_view_get` will succeed.
*/
bool rb_memory_view_available_p(VALUE obj);
/**
* If the given `obj` supports to export a MemoryView that conforms the given
* `flags`, this function fills `view` by the information of the MemoryView and
* returns `true`. In this case, the reference count of `obj` is increased.
*
* If the given combination of `obj` and `flags` cannot export a MemoryView,
* this function returns `false`. The content of `view` is not touched in this
* case.
*
* The exported MemoryView must be released by `rb_memory_view_release` when
* the MemoryView is no longer needed.
*/
bool rb_memory_view_get(VALUE obj, rb_memory_view_t* memory_view, int flags);
/**
* Release the given MemoryView `view` and decrement the reference count of
* `memory_view->obj`.
*
* Consumers must call this function when the MemoryView is no longer needed.
* Missing to call this function leads memory leak.
*/
bool rb_memory_view_release(rb_memory_view_t* memory_view);
/* for testing */
/** @cond INTERNAL_MACRO */
RUBY_EXTERN VALUE rb_memory_view_exported_object_registry;
RUBY_EXTERN const rb_data_type_t rb_memory_view_exported_object_registry_data_type;
/** @endcond */
RBIMPL_SYMBOL_EXPORT_END()
RBIMPL_ATTR_PURE()
/**
* Return `true` if the data in the MemoryView `view` is row-major or
* column-major contiguous.
*
* Return `false` otherwise.
*/
static inline bool
rb_memory_view_is_contiguous(const rb_memory_view_t *view)
{
if (rb_memory_view_is_row_major_contiguous(view)) {
return true;
}
else if (rb_memory_view_is_column_major_contiguous(view)) {
return true;
}
else {
return false;
}
}
#endif /* RUBY_BUFFER_H */
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