use std::io;
use std::io::{Read, Seek, Write, Stdout, Cursor};
use std::fs::{File};
pub enum Input {
File(File),
Cursor(Cursor<Box<[u8]>>),
}
pub enum Output {
File(File),
Standard(Stdout),
}
impl Read for Input {
fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
match *self {
Input::File(ref mut f) => f.read(buf),
Input::Cursor(ref mut c) => c.read(buf),
}
}
}
impl Seek for Input {
fn seek(&mut self, pos: io::SeekFrom) -> io::Result<u64> {
match *self {
Input::File(ref mut f) => f.seek(pos),
Input::Cursor(ref mut c) => c.seek(pos),
}
}
}
impl Write for Output {
fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
match *self {
Output::File(ref mut f) => f.write(buf),
Output::Standard(ref mut s) => s.write(buf),
}
}
fn flush(&mut self) -> io::Result<()> {
match *self {
Output::File(ref mut f) => f.flush(),
Output::Standard(ref mut s) => s.flush(),
}
}
}
pub trait ReadExt: Read {
fn read_cstring(&mut self) -> io::Result<String>;
fn read_compressed_int(&mut self) -> io::Result<u32>;
}
impl<T: Read> ReadExt for T {
fn read_cstring(&mut self) -> io::Result<String> {
let mut bytes: Vec<u8> = Vec::new();
for byte in self.bytes() {
let b = byte?;
if b == 0 {
break;
} else {
bytes.push(b);
}
}
Ok(String::from_utf8(bytes).unwrap())
}
fn read_compressed_int(&mut self) -> io::Result<u32> {
let mut i = 0;
let mut result: u32 = 0;
for byte in self.bytes() {
let b: u32 = byte?.into();
result = result | ((b & 0x7f) << (i * 7));
if b < 0x80 {
break;
}
i += 1;
}
Ok(result)
}
}
pub trait WriteExt: Write {
fn write_cstring<S: AsRef<[u8]>>(&mut self, s: S) -> io::Result<()>;
fn write_compressed_int(&mut self, x: u32) -> io::Result<usize>;
}
impl<T: Write> WriteExt for T {
fn write_cstring<S: AsRef<[u8]>>(&mut self, s: S) -> io::Result<()> {
self.write_all(s.as_ref())?;
self.write_all(b"\0")?;
Ok(())
}
fn write_compressed_int(&mut self, x: u32) -> io::Result<usize> {
let mut temp = x;
let mut len = 0;
while temp > 0x7f {
self.write(&[(0x80 | temp & 0x7f) as u8])?;
len += 1;
temp &= !0x7f;
temp >>= 7;
}
self.write(&[temp as u8])?;
Ok(len + 1)
}
}
pub fn compressed_int_len(x: u32) -> usize {
let mut temp = x;
let mut len = 0;
while temp > 0x7f {
len += 1;
temp &= !0x7f;
temp >>= 7;
}
len + 1
}