fat 0.0.2

Forensic library; parser and analyzer for FAT image
Documentation 
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//             DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
//                    Version 2, December 2004
//
// Copyright (C) 2018 Thomas Bailleux <thomas@bailleux.me>
//
// Everyone is permitted to copy and distribute verbatim or modified
// copies of this license document, and changing it is allowed as long
// as the name is changed.
//
//            DO WHAT THE FUCK YOU WANT TO PUBLIC LICENSE
//   TERMS AND CONDITIONS FOR COPYING, DISTRIBUTION AND MODIFICATION
//
//  0. You just DO WHAT THE FUCK YOU WANT TO.
//
// Author: zadig <thomas chr(0x40) bailleux.me>
use std;

pub(crate) trait FromSlice<T> {
    fn from_slice(buf: &[T]) -> Self;
}

impl FromSlice<u8> for usize {
    fn from_slice(buf: &[u8]) -> Self {
        let mut result = 0usize;
        let mut p = 0u32;
        for i in 0..buf.len() {
            result += (buf[i] as usize) * 256usize.pow(p);
            p += 1;
        }
        result
    }
}


impl FromSlice<u8> for u16 {
    fn from_slice(buf: &[u8]) -> Self {
        let mut result = 0u16;
        let mut p = 0u32;
        for i in 0..buf.len() {
            result += (buf[i] as u16) * 256u16.pow(p);
            p += 1;
        }
        result
    }
}

impl FromSlice<u8> for u32 {
    fn from_slice(buf: &[u8]) -> Self {
        let mut result = 0u32;
        let mut p = 0u32;
        for i in 0..buf.len() {
            result += (buf[i] as u32) * 256u32.pow(p);
            p += 1;
        }
        result
    }
}

impl FromSlice<u8> for i32 {
    fn from_slice(buf: &[u8]) -> Self {
        let mut result = 0i32;
        let mut p = 0u32;
        for i in 0..buf.len() {
            result += (buf[i] as i32) * 256i32.pow(p);
            p += 1;
        }
        result
    }
}

impl FromSlice<u8> for u64 {
    fn from_slice(buf: &[u8]) -> Self {
        let mut result = 0u64;
        let mut p = 0u32;
        for i in 0..buf.len() {
            result += (buf[i] as u64) * 256u64.pow(p);
            p += 1;
        }
        result
    }
}

pub(crate) fn fetch_unicode_string(
    content: &[u8],
    offset: usize,
    max_length: usize,
) -> std::string::String {
    let mut s = std::string::String::new();
    let mut i = 0;
    let limit = content.len();
    let limit2 = max_length * 2 + 2;
    while i < limit2 && i < limit && content[offset + i] != 0 {
        s.push(content[offset + i] as char);
        i += 2;
    }

    s
}