blob: c6e93ac1f2f4d4bd9fac9fa581970909c899feaa [file] [log] [blame]
//! Simple CRC bindings backed by miniz.c
use std::io::prelude::*;
use std::io;
use libc;
use ffi;
/// The CRC calculated by a [`CrcReader`].
///
/// [`CrcReader`]: struct.CrcReader.html
#[derive(Debug)]
pub struct Crc {
crc: libc::c_ulong,
amt: u32,
}
/// A wrapper around a [`Read`] that calculates the CRC.
///
/// [`Read`]: https://doc.rust-lang.org/std/io/trait.Read.html
#[derive(Debug)]
pub struct CrcReader<R> {
inner: R,
crc: Crc,
}
impl Crc {
/// Create a new CRC.
pub fn new() -> Crc {
Crc { crc: 0, amt: 0 }
}
/// bla
pub fn sum(&self) -> u32 {
self.crc as u32
}
/// The number of bytes that have been used to calculate the CRC.
/// This value is only accurate if the amount is lower than 2^32.
pub fn amount(&self) -> u32 {
self.amt
}
/// Update the CRC with the bytes in `data`.
pub fn update(&mut self, data: &[u8]) {
self.amt = self.amt.wrapping_add(data.len() as u32);
self.crc = unsafe {
ffi::mz_crc32(self.crc, data.as_ptr(), data.len() as libc::size_t)
};
}
/// Reset the CRC.
pub fn reset(&mut self) {
self.crc = 0;
self.amt = 0;
}
/// Combine the CRC with the CRC for the subsequent block of bytes.
pub fn combine(&mut self, additional_crc: &Crc) {
self.crc = unsafe {
ffi::mz_crc32_combine(self.crc as ::libc::c_ulong,
additional_crc.crc as ::libc::c_ulong,
additional_crc.amt as ::libc::off_t)
};
self.amt += additional_crc.amt;
}
}
impl<R: Read> CrcReader<R> {
/// Create a new CrcReader.
pub fn new(r: R) -> CrcReader<R> {
CrcReader {
inner: r,
crc: Crc::new(),
}
}
}
impl<R> CrcReader<R> {
/// Get the Crc for this CrcReader.
pub fn crc(&self) -> &Crc {
&self.crc
}
/// Get the reader that is wrapped by this CrcReader.
pub fn into_inner(self) -> R {
self.inner
}
/// Get the reader that is wrapped by this CrcReader by reference.
pub fn get_ref(&self) -> &R {
&self.inner
}
/// Get a mutable reference to the reader that is wrapped by this CrcReader.
pub fn get_mut(&mut self) -> &mut R {
&mut self.inner
}
/// Reset the Crc in this CrcReader.
pub fn reset(&mut self) {
self.crc.reset();
}
}
impl<R: Read> Read for CrcReader<R> {
fn read(&mut self, into: &mut [u8]) -> io::Result<usize> {
let amt = try!(self.inner.read(into));
self.crc.update(&into[..amt]);
Ok(amt)
}
}
impl<R: BufRead> BufRead for CrcReader<R> {
fn fill_buf(&mut self) -> io::Result<&[u8]> {
self.inner.fill_buf()
}
fn consume(&mut self, amt: usize) {
if let Ok(data) = self.inner.fill_buf() {
self.crc.update(&data[..amt]);
}
self.inner.consume(amt);
}
}