mcel_store_callbacks Struct Reference

The MCEL storage callback table. More...

#include <mcel.h>

Data Fields
void *	context
bool(*	write )(void *context, const uint8_t *loc, size_t loclen, const uint8_t *data, size_t datalen)
	Write a complete object at a logical location.
bool(*	read )(void *context, const uint8_t *loc, size_t loclen, uint8_t *data, size_t datalen, size_t *outread)
	Read a complete object from a logical location.
bool(*	append )(void *context, const uint8_t *loc, size_t loclen, const uint8_t *data, size_t datalen, uint64_t *outpos)
	Append bytes to an append-only object.
bool(*	size )(void *context, const uint8_t *loc, size_t loclen, uint64_t *outlen)
	Get the size of an object at a logical location.
bool(*	flush )(void *context, const uint8_t *loc, size_t loclen)
	Flush any buffered data for a logical location.

Detailed Description

The MCEL storage callback table.

The hosting application owns persistence. MCEL calls these functions to read and write opaque byte strings (blocks, checkpoint bundles, records, indexes).

Field Documentation

append

bool(* append) (void *context, const uint8_t *loc, size_t loclen, const uint8_t *data, size_t datalen, uint64_t *outpos)

Append bytes to an append-only object.

Parameters

context	The storage context.
loc	[const] A pointer to an application-defined location identifier.
loclen	The length of the location identifier in bytes.
data	[const] A pointer to the data buffer.
datalen	The data length in bytes.
outpos	A pointer to the returned append position offset, can be NULL.

Returns

Returns true on success.

context

void* context

The host-defined storage context pointer

flush

bool(* flush) (void *context, const uint8_t *loc, size_t loclen)

Flush any buffered data for a logical location.

Parameters

context	The storage context.
loc	[const] A pointer to an application-defined location identifier.
loclen	The length of the location identifier in bytes.

Returns

Returns true on success.

read

bool(* read) (void *context, const uint8_t *loc, size_t loclen, uint8_t *data, size_t datalen, size_t *outread)

Read a complete object from a logical location.

Parameters

context	The storage context.
loc	[const] A pointer to an application-defined location identifier.
loclen	The length of the location identifier in bytes.
data	A pointer to the output buffer.
datalen	The output buffer length in bytes.
outread	A pointer to the returned number of bytes read.

Returns

Returns true on success.

size

bool(* size) (void *context, const uint8_t *loc, size_t loclen, uint64_t *outlen)

Get the size of an object at a logical location.

Parameters

context	The storage context.
loc	[const] A pointer to an application-defined location identifier.
loclen	The length of the location identifier in bytes.
outlen	A pointer to the returned size in bytes.

Returns

Returns true on success.

write

bool(* write) (void *context, const uint8_t *loc, size_t loclen, const uint8_t *data, size_t datalen)

Write a complete object at a logical location.

Parameters

context	The storage context.
loc	[const] A pointer to an application-defined location identifier.
loclen	The length of the location identifier in bytes.
data	[const] A pointer to the data buffer.
datalen	The data length in bytes.

Returns

Returns true on success.

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The documentation for this struct was generated from the following file:

• C:/Users/stepp/Documents/Visual Studio 2022/Projects/C/MCEL/MCEL/mcel.h