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/* SPDX-License-Identifier: GPL-3.0-or-later */
/*
* data_reader.h
*
* Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
*/
#ifndef DATA_READER_H
#define DATA_READER_H
#include "config.h"
#include "sqfs/squashfs.h"
#include "sqfs/compress.h"
#include "fstree.h"
typedef struct data_reader_t data_reader_t;
/*
Create a data reader for accessing data blocks in a squashfs image.
Internally creates a fragment_reader_t (if applicable) to resolve
fragment indices.
Prints error messsages to stderr on failure.
*/
data_reader_t *data_reader_create(int fd, sqfs_super_t *super,
compressor_t *cmp);
void data_reader_destroy(data_reader_t *data);
/*
Use a file_info_t to locate and extract all blocks of the coresponding
file and its fragment, if it has one. The entire data is dumped to the
given file descriptor.
If allow_sparse is true, try to truncate and seek forward on outfd if a
zero block is found. If false, always write blocks of zeros to outfd.
Returns 0 on success, prints error messages to stderr on failure.
*/
int data_reader_dump_file(data_reader_t *data, file_info_t *fi, int outfd,
bool allow_sparse);
/*
Read a chunk of data from a file. Starting from 'offset' into the
uncompressed file, read 'size' bytes into 'buffer'.
Returns the number of bytes read, 0 if EOF, -1 on failure. Prints an
error message to stderr on failure.
*/
ssize_t data_reader_read(data_reader_t *data, file_info_t *fi,
uint64_t offset, void *buffer, size_t size);
#endif /* DATA_READER_H */
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