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use fewer macros without losing performance
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@reem
reem committed Apr 2, 2015
1 parent 0176115 commit 7407bad
Showing 1 changed file with 37 additions and 59 deletions.
96 changes: 37 additions & 59 deletions src/lib.rs
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Original file line number Diff line number Diff line change
Expand Up @@ -2,8 +2,7 @@
#![feature(core)]
#![allow(unused_assignments)]

use std::str;

use std::{str, mem, raw};

macro_rules! eof {
($buf:expr, $i:expr) => (
Expand All @@ -12,6 +11,7 @@ macro_rules! eof {
}
)
}

macro_rules! next {
($buf:expr, $i:ident) => ({
let buf = $buf;
Expand All @@ -31,32 +31,18 @@ macro_rules! expect {
}
}

macro_rules! slice {
($buf:ident[$from:expr;]) => ({
slice!($buf[$from; $buf.len()])
});
($buf:ident[$from:expr;$to:expr]) => {
unsafe {
use std::mem::transmute;
use std::raw::Slice;
transmute(Slice {
data: $buf.as_ptr().offset($from as isize),
len: $to - $from
})
}
}
#[inline(always)]
unsafe fn slice<T>(buf: &[T], start: usize, end: usize) -> &[T] {
mem::transmute(raw::Slice {
data: buf.as_ptr().offset(start as isize),
len: end - start
})
}

macro_rules! shrink {
($slice:ident, $to:expr) => ({
unsafe {
use std::mem::transmute;
use std::raw::Slice;
use $crate::Header;
let raw: &mut &mut Slice<Header> = transmute(&$slice);
raw.len = $to;
}
})
#[inline]
fn shrink<T>(slice: &mut &mut [T], len: usize) {
let raw: &mut raw::Slice<Header> = unsafe { mem::transmute(slice) };
raw.len = len;
}

/// Determines if byte is a token char.
Expand All @@ -69,19 +55,16 @@ macro_rules! shrink {
/// > / DIGIT / ALPHA
/// > ; any VCHAR, except delimiters
/// > ```
macro_rules! is_token {
($b:expr) => ({
let b = $b;
b > 0x1F && b < 0x7F
})
#[inline]
fn is_token(b: u8) -> bool {
b > 0x1F && b < 0x7F
}

macro_rules! parse {
($obj:ident.$field:ident = parse_version ($buf:expr)) => ({
$obj.$field = match try!(parse_version($buf)) {
Status::Complete(val) => {
let buf = $buf;
$buf = slice!(buf[8;]);
$buf = unsafe { slice($buf, 8, $buf.len()) };
Some(val)
},
Status::Partial => return Ok(Status::Partial)
Expand All @@ -90,8 +73,7 @@ macro_rules! parse {
($obj:ident.$field:ident = parse_code ($buf:expr)) => ({
$obj.$field = match try!(parse_code($buf)) {
Status::Complete(val) => {
let buf = $buf;
$buf = slice!(buf[3;]);
$buf = unsafe { slice($buf, 3, $buf.len()) };
Some(val)
},
Status::Partial => return Ok(Status::Partial)
Expand All @@ -100,8 +82,7 @@ macro_rules! parse {
($obj:ident.$field:ident = $action:ident ($buf:expr)) => ({
$obj.$field = match try!($action($buf)) {
Status::Complete(val) => {
let buf = $buf;
$buf = slice!(buf[val.len();]);
$buf = unsafe { slice($buf, val.len(), $buf.len()) };
Some(val)
},
Status::Partial => return Ok(Status::Partial)
Expand All @@ -116,20 +97,18 @@ macro_rules! newline {
match next!($buf, i) {
b'\r' => {
expect!($buf[i] == b'\n' => Ok(Status::Partial));
let buf = $buf;
$buf = slice!(buf[2;]);
$buf = unsafe { slice($buf, 2, $buf.len()) };
},
b'\n' => {
let buf = $buf;
$buf = slice!(buf[1;]);
$buf = unsafe { slice($buf, 1, $buf.len()) };
},
_ => return Err(Error::NewLine)
}
})
}


#[derive(Copy, Clone, PartialEq, Debug)]
#[derive(Copy, Clone, PartialEq, Eq, Debug)]
pub enum Error {
HeaderName,
HeaderValue,
Expand Down Expand Up @@ -193,9 +172,9 @@ impl<'a> Request<'a> {
pub fn parse(&mut self, mut buf: &'a [u8]) -> Result<Status<usize>, Error> {
let orig_len = buf.len();
parse!(self.method = parse_token(buf));
buf = slice!(buf[1;]);
buf = unsafe { slice(buf, 1, buf.len()) };
parse!(self.path = parse_token(buf));
buf = slice!(buf[1;]);
buf = unsafe { slice(buf, 1, buf.len()) };
parse!(self.version = parse_version(buf));
newline!(buf);

Expand Down Expand Up @@ -231,9 +210,9 @@ impl<'a> Response<'a> {
let orig_len = buf.len();

parse!(self.version = parse_version(buf));
buf = slice!(buf[1;]);
buf = unsafe { slice(buf, 1, buf.len()) };
parse!(self.code = parse_code(buf));
buf = slice!(buf[1;]);
buf = unsafe { slice(buf, 1, buf.len()) };
parse!(self.reason = parse_reason(buf));
newline!(buf);

Expand Down Expand Up @@ -317,7 +296,7 @@ fn parse_token(buf: &[u8]) -> Result<Status<&str>, Error> {
// all bytes up till `i` must have been `is_token`.
str::from_utf8_unchecked(&buf[..i - 1])
}));
} else if !is_token!(b) {
} else if !is_token(b) {
return Err(Error::Token);
}
}
Expand Down Expand Up @@ -371,12 +350,11 @@ fn parse_headers<'a>(headers: &mut &mut [Header<'a>], buf: &'a [u8]) -> Result<S
loop {
let b = next!(buf, i);
if b == b':' {
let subslice = slice!(buf[last_i; i - 1]);
header.name = unsafe {
str::from_utf8_unchecked(subslice)
str::from_utf8_unchecked(slice(buf, last_i, i - 1))
};
break;
} else if !is_token!(b) {
} else if !is_token(b) {
println!("{:?} {:?}", b, b as char);
return Err(Error::HeaderName);
}
Expand All @@ -398,14 +376,14 @@ fn parse_headers<'a>(headers: &mut &mut [Header<'a>], buf: &'a [u8]) -> Result<S
() => ({
let b = unsafe { *buf.get_unchecked(i) };
i += 1;
if !is_token!(b) {
if !is_token(b) {
if (b < 0o40 && b != 0o11) || b == 0o177 {
if b == b'\r' {
expect!(buf[i] == b'\n' => Err(Error::HeaderValue));
header.value = slice!(buf[last_i;i - 2]);
header.value = unsafe { slice(buf, last_i, i - 2) };
continue 'headers;
} else if b == b'\n' {
header.value = slice!(buf[last_i;i - 1]);
header.value = unsafe { slice(buf, last_i, i - 1) };
continue 'headers;
} else {
return Err(Error::HeaderValue);
Expand All @@ -426,14 +404,14 @@ fn parse_headers<'a>(headers: &mut &mut [Header<'a>], buf: &'a [u8]) -> Result<S
}
loop {
let b = next!(buf, i);
if !is_token!(b) {
if !is_token(b) {
if (b < 0o40 && b != 0o11) || b == 0o177 {
if b == b'\r' {
expect!(buf[i] == b'\n' => Err(Error::HeaderValue));
header.value = slice!(buf[last_i;i - 2]);
header.value = unsafe { slice(buf, last_i, i - 2) };
break;
} else if b == b'\n' {
header.value = slice!(buf[last_i;i - 1]);
header.value = unsafe { slice(buf, last_i, i - 1) };
break;
} else {
return Err(Error::HeaderValue);
Expand All @@ -444,13 +422,13 @@ fn parse_headers<'a>(headers: &mut &mut [Header<'a>], buf: &'a [u8]) -> Result<S
}
} // drop iter

shrink!(headers, num_headers);
shrink(headers, num_headers);
result
}

#[cfg(test)]
mod tests {
use super::{Request, Response, Status, EMPTY_HEADER};
use super::{Request, Response, Status, EMPTY_HEADER, shrink};

const NUM_OF_HEADERS: usize = 4;

Expand All @@ -460,7 +438,7 @@ mod tests {
{
let slice = &mut &mut arr[..];
assert_eq!(slice.len(), 16);
shrink!(slice, 4);
shrink(slice, 4);
assert_eq!(slice.len(), 4);
}
assert_eq!(arr.len(), 16);
Expand Down

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