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use std::str::{self, FromStr};
pub trait SectorExt {
fn get_sectors(&self) -> u64;
fn get_sector_size(&self) -> u64;
fn get_sector(&self, sector: Sector) -> u64 {
const MIB2: u64 = 2 * 1024 * 1024;
let end = || self.get_sectors() - (MIB2 / self.get_sector_size());
let megabyte = |size| (size * 1_000_000) / self.get_sector_size();
match sector {
Sector::Start => MIB2 / self.get_sector_size(),
Sector::End => end(),
Sector::Megabyte(size) => megabyte(size),
Sector::MegabyteFromEnd(size) => end() - megabyte(size),
Sector::Unit(size) => size,
Sector::UnitFromEnd(size) => end() - size,
Sector::Percent(value) => {
if value == ::std::u16::MAX {
self.get_sectors()
} else {
((self.get_sectors() * self.get_sector_size()) / ::std::u16::MAX as u64)
* value as u64 / self.get_sector_size()
}
}
}
}
}
#[derive(Debug, PartialEq, Clone, Copy, Hash)]
pub enum Sector {
Start,
End,
Unit(u64),
UnitFromEnd(u64),
Megabyte(u64),
MegabyteFromEnd(u64),
Percent(u16),
}
impl From<u64> for Sector {
fn from(sectors: u64) -> Sector { Sector::Unit(sectors) }
}
impl FromStr for Sector {
type Err = &'static str;
fn from_str(input: &str) -> Result<Self, Self::Err> {
if input.ends_with('M') {
if input.starts_with('-') {
if let Ok(value) = input[1..input.len() - 1].parse::<u64>() {
return Ok(Sector::MegabyteFromEnd(value));
}
} else if let Ok(value) = input[..input.len() - 1].parse::<u64>() {
return Ok(Sector::Megabyte(value));
}
} else if input.ends_with('%') {
if let Ok(value) = input[..input.len() - 1].parse::<u16>() {
if value <= 100 {
return Ok(Sector::Percent(value));
}
}
} else if input == "start" {
return Ok(Sector::Start);
} else if input == "end" {
return Ok(Sector::End);
} else if input.starts_with('-') {
if let Ok(value) = input[1..input.len()].parse::<u64>() {
return Ok(Sector::UnitFromEnd(value));
}
} else if let Ok(value) = input[..input.len()].parse::<u64>() {
return Ok(Sector::Unit(value));
}
Err("invalid sector value")
}
}
#[cfg(test)]
mod tests {
use super::*;
use std::u16;
struct FictionalBlock(u64);
impl SectorExt for FictionalBlock {
fn get_sectors(&self) -> u64 { self.0 }
fn get_sector_size(&self) -> u64 { 512 }
}
#[test]
fn sector_get() {
let block = FictionalBlock (100_000_000);
assert_eq!(4096, block.get_sector(Sector::Start));
assert_eq!(99_995_904, block.get_sector(Sector::End));
assert_eq!(1000, block.get_sector(Sector::Unit(1000)));
assert_eq!(99_994_904, block.get_sector(Sector::UnitFromEnd(1000)));
}
#[test]
fn sector_get_megabyte() {
let block = FictionalBlock (100_000_000);
assert_eq!(2_000_000, block.get_sector(Sector::Megabyte(1024)));
assert_eq!(97_995_904, block.get_sector(Sector::MegabyteFromEnd(1024)));
}
#[test]
fn sector_get_percent() {
let block = FictionalBlock (100_000_000);
assert_eq!(0, block.get_sector(Sector::Percent(0)));
assert_eq!(24_998_826, block.get_sector(Sector::Percent(u16::MAX / 4)));
assert_eq!(49_999_178, block.get_sector(Sector::Percent(u16::MAX / 2)));
assert_eq!(100_000_000, block.get_sector(Sector::Percent(u16::MAX)));
}
#[test]
fn sector_percentages() {
assert_eq!("0%".parse::<Sector>(), Ok(Sector::Percent(0)));
assert_eq!("50%".parse::<Sector>(), Ok(Sector::Percent(50)));
assert_eq!("100%".parse::<Sector>(), Ok(Sector::Percent(100)));
}
#[test]
fn sector_ends() {
assert_eq!("start".parse::<Sector>(), Ok(Sector::Start));
assert_eq!("end".parse::<Sector>(), Ok(Sector::End));
}
#[test]
fn sector_units() {
assert_eq!("0".parse::<Sector>(), Ok(Sector::Unit(0)));
assert_eq!("1024".parse::<Sector>(), Ok(Sector::Unit(1024)));
assert_eq!("-1024".parse::<Sector>(), Ok(Sector::UnitFromEnd(1024)));
}
#[test]
fn sector_megabytes() {
assert_eq!("0M".parse::<Sector>(), Ok(Sector::Megabyte(0)));
assert_eq!("500M".parse::<Sector>(), Ok(Sector::Megabyte(500)));
assert_eq!("20480M".parse::<Sector>(), Ok(Sector::Megabyte(20480)));
assert_eq!("-0M".parse::<Sector>(), Ok(Sector::MegabyteFromEnd(0)));
assert_eq!("-500M".parse::<Sector>(), Ok(Sector::MegabyteFromEnd(500)));
assert_eq!(
"-20480M".parse::<Sector>(),
Ok(Sector::MegabyteFromEnd(20480))
);
}
}