/* SPDX-License-Identifier: LGPL-3.0-or-later */
/*
 * util.h
 *
 * Copyright (C) 2019 David Oberhollenzer <goliath@infraroot.at>
 */
#ifndef UTIL_H
#define UTIL_H

#include "config.h"
#include "sqfs/predef.h"

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

#if defined(__GNUC__) || defined(__clang__)
#define UI_ADD_OV __builtin_uadd_overflow
#define UL_ADD_OV __builtin_uaddl_overflow
#define ULL_ADD_OV __builtin_uaddll_overflow

#define UI_MUL_OV __builtin_umul_overflow
#define UL_MUL_OV __builtin_umull_overflow
#define ULL_MUL_OV __builtin_umulll_overflow
#else
#error Sorry, I do not know how to trap integer overflows with this compiler
#endif

#if SIZEOF_SIZE_T <= SIZEOF_INT
#define SZ_ADD_OV UI_ADD_OV
#define SZ_MUL_OV UI_MUL_OV
#elif SIZEOF_SIZE_T == SIZEOF_LONG
#define SZ_ADD_OV UL_ADD_OV
#define SZ_MUL_OV UL_MUL_OV
#elif SIZEOF_SIZE_T == SIZEOF_LONG_LONG
#define SZ_ADD_OV ULL_ADD_OV
#define SZ_MUL_OV ULL_MUL_OV
#else
#error Cannot determine maximum value of size_t
#endif


/* layout structure for sparse files, indicating where the actual data is */
typedef struct sparse_map_t {
	struct sparse_map_t *next;
	uint64_t offset;
	uint64_t count;
} sparse_map_t;

/*
  A wrapper around the write() system call. It retries the write if it is
  interrupted by a signal or only part of the data was written. Returns 0
  on success. Writes to stderr on failure using 'errstr' as a perror style
  error prefix.
*/
SQFS_INTERNAL
int write_data(const char *errstr, int fd, const void *data, size_t size);

/*
  A wrapper around the read() system call. It retries the read if it is
  interrupted by a signal or less than the desired size was read. Returns 0
  on success. Writes to stderr on failure using 'errstr' as a perror style
  error prefix.
*/
SQFS_INTERNAL
int read_data(const char *errstr, int fd, void *buffer, size_t size);

/*
  Similar to read_data but wrapps pread() instead of read().
*/
SQFS_INTERNAL
int read_data_at(const char *errstr, off_t location,
		 int fd, void *buffer, size_t size);

/*
  A common implementation of the '--version' command line flag.

  Prints out version information. The program name is extracted from the
  BSD style __progname global variable.
*/
SQFS_INTERNAL
void print_version(void);

/*
  A wrapper around mkdir() that behaves like 'mkdir -p'. It tries to create
  every component of the given path and skips already existing entries.

  Returns 0 on success.
*/
SQFS_INTERNAL
int mkdir_p(const char *path);

/* Returns 0 on success. On failure, prints error message to stderr. */
SQFS_INTERNAL
int pushd(const char *path);

/* Same as pushd, but the string doesn't have to be null-terminated. */
SQFS_INTERNAL
int pushdn(const char *path, size_t len);

/* Returns 0 on success. On failure, prints error message to stderr. */
SQFS_INTERNAL
int popd(void);

/*
  Write zero bytes to an output file to padd it to specified block size.
  Returns 0 on success. On failure, prints error message to stderr.
*/
SQFS_INTERNAL
int padd_file(int outfd, uint64_t size, size_t blocksize);

SQFS_INTERNAL
int padd_sqfs(sqfs_file_t *file, uint64_t size, size_t blocksize);

/*
  Helper for allocating data structures with flexible array members.

  'base_size' is the size of the struct itself, 'item_size' the size of a
  single array element and 'nmemb' the number of elements.

  Iternally checks for arithmetic overflows when allocating the combined thing.
 */
SQFS_INTERNAL
void *alloc_flex(size_t base_size, size_t item_size, size_t nmemb);

/* Basically the same as calloc, but *ALWAYS* does overflow checking */
SQFS_INTERNAL
void *alloc_array(size_t item_size, size_t nmemb);

/* allocates len + 1 (for the null-terminator) and does overflow checking */
SQFS_INTERNAL
void *alloc_string(size_t len);

#endif /* UTIL_H */