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/* SPDX-License-Identifier: GPL-3.0-or-later */
#ifndef FRAG_READER_H
#define FRAG_READER_H
#include "squashfs.h"
#include "compress.h"
#include <stdint.h>
#include <stddef.h>
/* A simple interface for accessing fragments in a SquashFS image */
typedef struct {
sqfs_fragment_t *tbl;
size_t num_fragments;
int fd;
compressor_t *cmp;
size_t block_size;
size_t used;
size_t current_index;
uint8_t buffer[];
} frag_reader_t;
/* Reads and decodes the fragment table from the image. Cleans up after itself
and prints error messages to stderr on the way if it fails. */
frag_reader_t *frag_reader_create(sqfs_super_t *super, int fd,
compressor_t *cmp);
void frag_reader_destroy(frag_reader_t *f);
/*
Read data from a fragment.
The function takes care of loading and uncompressing the fragment block
(which is skipped if it has already been loaded earlier).
`index` is a fragment index from an inode, `offset` is a byte offset into
the fragment block and `size` is the number of bytes to copy into the
destination buffer.
Returns 0 on success. Prints error messages to stderr on failure (including
index out of bounds).
*/
int frag_reader_read(frag_reader_t *f, size_t index, size_t offset,
void *buffer, size_t size);
#endif /* FRAG_READER_H */
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