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extern crate buf_redux;
extern crate memchr;
use self::buf_redux::BufReader;
use self::memchr::memchr;
use std::cmp;
use std::borrow::Borrow;
use std::io;
use std::io::prelude::*;
#[derive(Debug)]
pub struct BoundaryReader<R> {
buf: BufReader<R>,
boundary: Vec<u8>,
search_idx: usize,
boundary_read: bool,
at_end: bool,
}
impl<R> BoundaryReader<R> where R: Read {
#[doc(hidden)]
pub fn from_reader<B: Into<Vec<u8>>>(reader: R, boundary: B) -> BoundaryReader<R> {
BoundaryReader {
buf: BufReader::new(reader),
boundary: boundary.into(),
search_idx: 0,
boundary_read: false,
at_end: false,
}
}
fn read_to_boundary(&mut self) -> io::Result<&[u8]> {
use log::LogLevel;
let buf = try!(fill_buf_min(&mut self.buf, self.boundary.len()));
if log_enabled!(LogLevel::Trace) {
}
while !(self.boundary_read || self.at_end) && self.search_idx < buf.len() {
let lookahead = &buf[self.search_idx..];
let maybe_boundary = memchr(self.boundary[0], lookahead);
self.search_idx = match maybe_boundary {
Some(boundary_start) => self.search_idx + boundary_start,
None => buf.len(),
};
if self.search_idx + self.boundary.len() <= buf.len() {
let test = &buf[self.search_idx .. self.search_idx + self.boundary.len()];
match first_nonmatching_idx(test, &self.boundary) {
Some(idx) => self.search_idx += idx,
None => self.boundary_read = true,
}
} else {
break;
}
}
let mut buf_end = self.search_idx;
if self.boundary_read && self.search_idx >= 2 {
let two_bytes_before = &buf[self.search_idx - 2 .. self.search_idx];
if two_bytes_before == &*b"\r\n" {
buf_end -= 2;
}
}
let ret_buf = &buf[..buf_end];
Ok(ret_buf)
}
#[doc(hidden)]
pub fn consume_boundary(&mut self) -> io::Result<()> {
if self.at_end {
return Ok(());
}
while !self.boundary_read {
let buf_len = try!(self.read_to_boundary()).len();
if buf_len == 0 {
break;
}
self.consume(buf_len);
}
self.buf.consume(self.search_idx + self.boundary.len());
self.search_idx = 0;
self.boundary_read = false;
Ok(())
}
#[allow(unused)]
#[doc(hidden)]
pub fn set_boundary<B: Into<Vec<u8>>>(&mut self, boundary: B) {
self.boundary = boundary.into();
}
}
impl<R> Borrow<R> for BoundaryReader<R> {
fn borrow(&self) -> &R {
self.buf.get_ref()
}
}
impl<R> Read for BoundaryReader<R> where R: Read {
fn read(&mut self, out: &mut [u8]) -> io::Result<usize> {
let read = {
let mut buf = try!(self.read_to_boundary());
buf.read(out).unwrap()
};
self.consume(read);
Ok(read)
}
}
impl<R> BufRead for BoundaryReader<R> where R: Read {
fn fill_buf(&mut self) -> io::Result<&[u8]> {
self.read_to_boundary()
}
fn consume(&mut self, amt: usize) {
let true_amt = cmp::min(amt, self.search_idx);
self.buf.consume(true_amt);
self.search_idx -= true_amt;
}
}
fn fill_buf_min<R: Read>(buf: &mut BufReader<R>, min: usize) -> io::Result<&[u8]> {
if buf.available() < min {
try!(buf.read_into_buf());
}
Ok(buf.get_buf())
}
fn first_nonmatching_idx(left: &[u8], right: &[u8]) -> Option<usize> {
for (idx, (lb, rb)) in left.iter().zip(right).enumerate() {
if lb != rb {
return Some(idx);
}
}
None
}