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/*
Copyright 2020 Google LLC
Use of this source code is governed by a BSD-style
license that can be found in the LICENSE file or at
https://developers.google.com/open-source/licenses/bsd
*/
#ifndef REFTABLE_BLOCKSOURCE_H
#define REFTABLE_BLOCKSOURCE_H
#include <stdint.h>
/* block_source is a generic wrapper for a seekable readable file.
*/
struct reftable_block_source {
struct reftable_block_source_vtable *ops;
void *arg;
};
/* a contiguous segment of bytes. It keeps track of its generating block_source
* so it can return itself into the pool. */
struct reftable_block {
uint8_t *data;
size_t len;
struct reftable_block_source source;
};
/* block_source_vtable are the operations that make up block_source */
struct reftable_block_source_vtable {
/* returns the size of a block source */
uint64_t (*size)(void *source);
/*
* Reads a segment from the block source. It is an error to read beyond
* the end of the block.
*/
ssize_t (*read_block)(void *source, struct reftable_block *dest,
uint64_t off, uint32_t size);
/* mark the block as read; may return the data back to malloc */
void (*return_block)(void *source, struct reftable_block *blockp);
/* release all resources associated with the block source */
void (*close)(void *source);
};
/* opens a file on the file system as a block_source */
int reftable_block_source_from_file(struct reftable_block_source *block_src,
const char *name);
#endif
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