/**
 * @file tarfs_util.h
 *
 * Header file for tarfs_util.c
 * Contains declarations of helper functions for tarfs_tar.c
 *
 * @author Jaroslav Drazan <jaroslavdrazan@seznam.cz>
 * @author Petr Cermak <xgxg@seznam.cz>
 */

/* ************************************************************************* *
 *                                                                           *
 *   This program is free software; you can redistribute it and/or modify    *
 *   it under the terms of the GNU General Public License as published by    *
 *   the Free Software Foundation; either version 2 of the License, or       *
 *   (at your option) any later version.                                     *
 *                                                                           *
 * ************************************************************************* */

#include <linux/fs.h>
#include <linux/types.h>
#include <linux/errno.h>
#ifndef __TARFS_UTIL_H__
#define __TARFS_UTIL_H__


/**
 * @brief Reads block from device
 *
 * Reads #i block from device specified in super block s
 *
 * @param s Super block
 * @param i No. of block
 * @param blok Allocated buffer in which to store data (size TAFS_BLKSIZE)
 * @return 1 - OK, 0 - error
 */
int read_block(struct super_block* s, unsigned long i, void* blok);


/**
 * @brief Checks if given block is full of zeroes
 *
 * @param blok Block of data to check
 * @param size Size of block
 * @return 1 - OK, 0 - some non-zero character found or error
 */
int is_nullblock(void *blok, unsigned long size);

/**
 * @brief Compares two strings
 *
 * b must be zero-terminated.
 *
 * @param a First string
 * @param b Second string
 * @param first_length maximum length of a
 * @return 1 - equal, 0 - nonequal
 */
int name_comparator(void* a, void* b, int first_length);

/**
 * @brief Compares two strings, (except trailing '/')
 *
 * b must be zero-terminated.
 *
 * @param a First string
 * @param b Second string
 * @param first_length maximum length of a
 * @param second_length maximum length of b
 * @return 1 - equal, 0 - nonequal
 * @see name_comparator
 */
int name_comparator2(void* a, void* b, unsigned int first_length, unsigned int second_length);

/** 
 * @brief Compares two paths (strings)
 *
 * sais, whether the dname is right prefix of fname. 
 * It's equal to dname contains fname* 
 * @param dname full path of directory (char*, but couldn't be NULL-terminated)
 * @param dsize size of dname 
 * @param fname full file path (char*, but couldn't be NULL-terminated)
 * @param fsize size of fname 
 * @return 1 - dname contains fname, 0 - dname is not ancestor of fname in dir tree
 *  - can be changed by makro TARFS_CAN_ADD-1 - dname is ancestor, but not father
 * @see TARFS_CAN_ADD
 */
int is_right_prefix(char* dname, unsigned int dsize, char* fname, unsigned int fsize);

/**
 * @brief Converts octal number into decimal integer
 *
 * Supposes that the number is in big endian format
 *
 * @param what Number in octal format (string)
 * @param length Length of what - string
 * @return Number in decimal format, TARFS_EVAL - error
 */
unsigned long oct_to_dec(void* what, unsigned int length);

/**
 * @brief Checks if given character is '0' - '7'
 *
 * @param ch Character
 * @return 0 - no, nonzero - yes
 */
int is_octal(char ch);

/**
 * @brief Ceil value of nom / denom
 *
 * @param nom Nominator
 * @param denom Denominator
 * @return Ceil value of nom / denom
 */
unsigned long hcc(unsigned long co, unsigned long cim);

/**
 * @brief Returns length of filename stored in one block
 *
 * @param name Any zero-terminated string
 * @return min(length of name, 100)
 */
unsigned int short_name_size(char* name);

#endif // __TARFS_UTIL_H__