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/* SPDX-License-Identifier: LGPL-3.0-or-later */
/*
* table.h - This file is part of libsquashfs
*
* Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
*
* This program is free software: you can redistribute it and/or modify
* it under the terms of the GNU Lesser General Public License as published
* by the Free Software Foundation, either version 3 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public License
* along with this program. If not, see <https://www.gnu.org/licenses/>.
*/
#ifndef SQFS_TABLE_H
#define SQFS_TABLE_H
#include "sqfs/predef.h"
/**
* @file table.h
*
* @brief Contains helper functions for reading or writing tables.
*/
#ifdef __cplusplus
extern "C" {
#endif
/**
* @brief Write a table to disk.
*
* This function takes an in-memory array, breaks it down into meta data
* blocks, compresses and writes those blocks to the given output file and
* then writes a raw list of 64 bit absolute locations of each meta data
* block. The position of the location list is returned through a pointer.
*
* @param file The output file to write to.
* @param cmp A compressor to use for compressing the meta data blocks.
* @param data A pointer to a array to divide into blocks and write to disk.
* @param table_size The size of the input array in bytes.
* @param start Returns the absolute position of the location list.
*
* @return Zero on success, an @ref E_SQFS_ERROR value on failure.
*/
SQFS_API int sqfs_write_table(sqfs_file_t *file, sqfs_compressor_t *cmp,
const void *data, size_t table_size,
uint64_t *start);
/**
* @brief Read a table from a SquashFS filesystem.
*
* This function takes an absolute position and an array size as input. It
* then computes the number of meta data blocks required to store this array
* and reads that many 64 bit integers from the given start location. Each
* integer is interpreted as the location of a meta data block containing the
* respective array chunk.
*
* The entire data encoded in that way is read and uncompressed into memory.
*
* @param file An input file to read from.
* @param cmp A compressor to use for uncompressing the meta data block.
* @param table_size The size of the entire array in bytes.
* @param location The absolute position of the location list.
* @param lower_limit The lowest "sane" position at which to expect a meta
* data block. Anything less than that is interpreted
* as an out-of-bounds read.
* @param upper_limit The highest "sane" position at which to expect a meta
* data block. Anything after that is interpreted as an
* out-of-bounds read.
* @param out Returns a pointer to the table in memory.
*
* @return Zero on success, an @ref E_SQFS_ERROR value on failure.
*/
SQFS_API int sqfs_read_table(sqfs_file_t *file, sqfs_compressor_t *cmp,
size_t table_size, uint64_t location,
uint64_t lower_limit, uint64_t upper_limit,
void **out);
#ifdef __cplusplus
}
#endif
#endif /* SQFS_TABLE_H */
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