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use std::io;
use std::io::{Read, Write};
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)
}
}