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replace unsafe content length implementation

This commit is contained in:
Rob Ede 2020-02-06 23:51:02 +00:00
parent 6ab7cfa2be
commit 82b2786d6b
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@ -1,4 +1,4 @@
use std::{io, mem, ptr, slice};
use std::{io, ptr, slice};
use bytes::{BufMut, BytesMut};
use http::Version;
@ -14,9 +14,7 @@ const DEC_DIGITS_LUT: &[u8] = b"0001020304050607080910111213141516171819\
pub(crate) const STATUS_LINE_BUF_SIZE: usize = 13;
pub(crate) fn write_status_line(version: Version, mut n: u16, bytes: &mut BytesMut) {
let mut buf: [u8; STATUS_LINE_BUF_SIZE] = [
b'H', b'T', b'T', b'P', b'/', b'1', b'.', b'1', b' ', b' ', b' ', b' ', b' ',
];
let mut buf: [u8; STATUS_LINE_BUF_SIZE] = *b"HTTP/1.1 ";
match version {
Version::HTTP_2 => buf[5] = b'2',
Version::HTTP_10 => buf[7] = b'0',
@ -64,60 +62,55 @@ pub(crate) fn write_status_line(version: Version, mut n: u16, bytes: &mut BytesM
}
}
const DIGITS_START: u8 = b'0';
/// NOTE: bytes object has to contain enough space
pub fn write_content_length(mut n: usize, bytes: &mut BytesMut) {
pub fn write_content_length(n: usize, bytes: &mut BytesMut) {
bytes.put_slice(b"\r\ncontent-length: ");
if n < 10 {
let mut buf: [u8; 21] = [
b'\r', b'\n', b'c', b'o', b'n', b't', b'e', b'n', b't', b'-', b'l', b'e',
b'n', b'g', b't', b'h', b':', b' ', b'0', b'\r', b'\n',
];
buf[18] = (n as u8) + b'0';
bytes.put_slice(&buf);
bytes.put_u8(DIGITS_START + (n as u8));
} else if n < 100 {
let mut buf: [u8; 22] = [
b'\r', b'\n', b'c', b'o', b'n', b't', b'e', b'n', b't', b'-', b'l', b'e',
b'n', b'g', b't', b'h', b':', b' ', b'0', b'0', b'\r', b'\n',
];
let d1 = n << 1;
unsafe {
ptr::copy_nonoverlapping(
DEC_DIGITS_LUT.as_ptr().add(d1),
buf.as_mut_ptr().offset(18),
2,
);
}
bytes.put_slice(&buf);
let n = n as u8;
let d10 = n / 10;
let d1 = n % 10;
bytes.put_u8(DIGITS_START + d10);
bytes.put_u8(DIGITS_START + d1);
} else if n < 1000 {
let mut buf: [u8; 23] = [
b'\r', b'\n', b'c', b'o', b'n', b't', b'e', b'n', b't', b'-', b'l', b'e',
b'n', b'g', b't', b'h', b':', b' ', b'0', b'0', b'0', b'\r', b'\n',
];
// decode 2 more chars, if > 2 chars
let d1 = (n % 100) << 1;
n /= 100;
unsafe {
ptr::copy_nonoverlapping(
DEC_DIGITS_LUT.as_ptr().add(d1),
buf.as_mut_ptr().offset(19),
2,
)
};
let n = n as u16;
// decode last 1
buf[18] = (n as u8) + b'0';
let d100 = (n / 100) as u8;
let d10 = ((n / 10) % 10) as u8;
let d1 = (n % 10) as u8;
bytes.put_slice(&buf);
bytes.put_u8(DIGITS_START + d100);
bytes.put_u8(DIGITS_START + d10);
bytes.put_u8(DIGITS_START + d1);
} else if n < 10000 {
let n = n as u16;
let d1000 = (n / 1000) as u8;
let d100 = ((n / 100) % 10) as u8;
let d10 = ((n / 10) % 10) as u8;
let d1 = (n % 10) as u8;
bytes.put_u8(DIGITS_START + d1000);
bytes.put_u8(DIGITS_START + d100);
bytes.put_u8(DIGITS_START + d10);
bytes.put_u8(DIGITS_START + d1);
} else {
bytes.put_slice(b"\r\ncontent-length: ");
convert_usize(n, bytes);
write_usize(n, bytes);
}
bytes.put_slice(b"\r\n");
}
pub(crate) fn convert_usize(mut n: usize, bytes: &mut BytesMut) {
pub(crate) fn write_usize(mut n: usize, bytes: &mut BytesMut) {
let mut curr: isize = 39;
let mut buf: [u8; 41] = unsafe { mem::MaybeUninit::uninit().assume_init() };
buf[39] = b'\r';
buf[40] = b'\n';
let mut buf = [0u8; 39];
let buf_ptr = buf.as_mut_ptr();
let lut_ptr = DEC_DIGITS_LUT.as_ptr();
@ -165,7 +158,7 @@ pub(crate) fn convert_usize(mut n: usize, bytes: &mut BytesMut) {
unsafe {
bytes.extend_from_slice(slice::from_raw_parts(
buf_ptr.offset(curr),
41 - curr as usize,
39 - curr as usize,
));
}
}
@ -231,5 +224,11 @@ mod tests {
bytes.reserve(50);
write_content_length(5909, &mut bytes);
assert_eq!(bytes.split().freeze(), b"\r\ncontent-length: 5909\r\n"[..]);
bytes.reserve(50);
write_content_length(10001, &mut bytes);
assert_eq!(bytes.split().freeze(), b"\r\ncontent-length: 10001\r\n"[..]);
bytes.reserve(50);
write_content_length(59094, &mut bytes);
assert_eq!(bytes.split().freeze(), b"\r\ncontent-length: 59094\r\n"[..]);
}
}