common.h

/*
 * Copyright (c) 2012 Dave Vasilevsky <dave@vasilevsky.ca>
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR(S) ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR(S) BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
#ifndef SQFS_COMMON_H
#define SQFS_COMMON_H

#include "config.h"

#include <stdbool.h>
#include <stdint.h>
#include <sys/types.h>

#ifdef _WIN32
# include <win32.h>
# include <intrin.h>
# define atomic_inc_relaxed(ptr) \
	_InterlockedIncrement(ptr)
# define atomic_dec_acqrel(ptr) \
	_InterlockedDecrement(ptr)
#else
	typedef mode_t sqfs_mode_t;
	typedef uid_t sqfs_id_t;
	typedef off_t sqfs_off_t;
	typedef int sqfs_fd_t;

# define atomic_inc_relaxed(ptr) \
	__atomic_add_fetch(&block->refcount, 1, __ATOMIC_RELAXED)
# define atomic_dec_acqrel(ptr) \
	__atomic_sub_fetch(&block->refcount, 1, __ATOMIC_ACQ_REL)

#endif

typedef enum {
	SQFS_OK,
	SQFS_ERR,
	SQFS_BADFORMAT,		/* unsupported file format */
	SQFS_BADVERSION,	/* unsupported squashfs version */
	SQFS_BADCOMP,		/* unsupported compression method */
	SQFS_UNSUP			/* unsupported feature */
} sqfs_err;

#define SQFS_INODE_ID_BYTES 6
typedef uint64_t sqfs_inode_id;
typedef uint32_t sqfs_inode_num;

typedef struct sqfs sqfs;
typedef struct sqfs_inode sqfs_inode;

typedef struct {
	size_t size;
	void *data;
	long refcount;
} sqfs_block;

typedef struct {
	sqfs_off_t block;
	size_t offset;
} sqfs_md_cursor;

/* Increment the refcount on the block. */
static inline void sqfs_block_ref(sqfs_block *block) {
	atomic_inc_relaxed(&block->refcount);
}

/* decrement the refcount on the block, return non-zero if we held the last
 * reference.
 */
static inline int sqfs_block_deref(sqfs_block *block) {
	return atomic_dec_acqrel(&block->refcount) == 0;
}

#endif