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/* SPDX-License-Identifier: LGPL-3.0-or-later */
/*
* block.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_BLOCK_H
#define SQFS_BLOCK_H
#include "sqfs/predef.h"
/**
* @file block.h
*
* @brief Contains on-disk data structures for data block management,
* helper macros and the higher level @ref sqfs_block_t structure.
*/
#define SQFS_META_BLOCK_SIZE 8192
#define SQFS_IS_BLOCK_COMPRESSED(size) (((size) & (1 << 24)) == 0)
#define SQFS_ON_DISK_BLOCK_SIZE(size) ((size) & ((1 << 24) - 1))
#define SQFS_IS_SPARSE_BLOCK(size) (SQFS_ON_DISK_BLOCK_SIZE(size) == 0)
/**
* @struct sqfs_fragment_t
*
* @brief Data structure that makes up the fragment table entries.
*/
struct sqfs_fragment_t {
/**
* @brief Location of the fragment block on-disk.
*/
sqfs_u64 start_offset;
/**
* @brief Size of the fragment block in bytes.
*/
sqfs_u32 size;
/**
* @brief Unused. Always initialize this to 0.
*/
sqfs_u32 pad0;
};
/**
* @enum E_SQFS_BLK_FLAGS
*
* @brief Generic flags that tell the processor what to do with a block and
* flags that the processor sets when it is done with a block.
*/
typedef enum {
/**
* @brief Only calculate checksum, do NOT compress the data.
*
* If set, the blocks of a file will not be compressed by the
* @ref sqfs_data_writer_t.
*/
SQFS_BLK_DONT_COMPRESS = 0x0001,
/**
* @brief Align the block on disk to device block size.
*
* If set, the @ref sqfs_data_writer_t will add padding before the
* first block of the affected file and after the last block.
*/
SQFS_BLK_ALIGN = 0x0002,
/**
* @brief Don't add the tail end of a file to a fragment block.
*
* If set, the @ref sqfs_data_writer_t will always generate a final
* block for a file, even if it is truncated. It will not add the
* tail end to a fragment block.
*/
SQFS_BLK_DONT_FRAGMENT = 0x0004,
/**
* @brief Set by the @ref sqfs_data_writer_t on the first
* block of a file.
*/
SQFS_BLK_FIRST_BLOCK = 0x0800,
/**
* @brief Set by the @ref sqfs_data_writer_t on the last
* block of a file.
*/
SQFS_BLK_LAST_BLOCK = 0x1000,
/**
* @brief Set by the @ref sqfs_data_writer_t to indicate that a block
* is a tail end of a file and the block.
*/
SQFS_BLK_IS_FRAGMENT = 0x2000,
/**
* @brief Set by the @ref sqfs_data_writer_t on fragment blocks that
* it generates.
*/
SQFS_BLK_FRAGMENT_BLOCK = 0x4000,
/**
* @brief Set by @ref sqfs_data_writer_t if the block was
* actually compressed.
*/
SQFS_BLK_IS_COMPRESSED = 0x8000,
/**
* @brief The combination of all flags that are user settable.
*/
SQFS_BLK_USER_SETTABLE_FLAGS = 0x0007,
} E_SQFS_BLK_FLAGS;
/**
* @struct sqfs_block_t
*
* @brief Encapsulates a chunk of data to be processed by the block processor.
*/
struct sqfs_block_t {
/**
* @brief Used internally, existing value is ignored and overwritten
* when enqueueing a block.
*/
sqfs_block_t *next;
/**
* @brief Used internally, existing value is ignored and overwritten
* when enqueueing a block.
*/
sqfs_u32 sequence_number;
/**
* @brief Size of the data area.
*/
sqfs_u32 size;
/**
* @brief Checksum of the input data.
*/
sqfs_u32 checksum;
/**
* @brief Data block index within the inode.
*/
sqfs_u32 index;
/**
* @brief The squashfs inode related to this block.
*/
sqfs_inode_generic_t *inode;
/**
* @brief User settable flag field.
*
* A combination of @ref E_SQFS_BLK_FLAGS and custom, user
* settable flags.
*/
sqfs_u32 flags;
/**
* @brief Raw data to be processed.
*/
sqfs_u8 data[];
};
#endif /* SQFS_BLOCK_H */
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