filetypes/types/utils/
common.rs

1use byteorder::{BigEndian, LittleEndian, ReadBytesExt};
2use std::{io::Cursor, str};
3pub fn compare_bytes(slice: &[u8], subs: &[u8], offset: usize) -> bool {
4    let s1 = subs.len();
5    s1 + offset <= slice.len() && *subs == slice[offset..s1 + offset]
6}
7
8pub fn bigendian_bytes(buf: &[u8]) -> u32 {
9    Cursor::new(buf).read_u32::<BigEndian>().unwrap()
10}
11
12pub fn littleendian_bytes(buf: &[u8]) -> u32 {
13    Cursor::new(buf).read_u32::<LittleEndian>().unwrap()
14}
15
16pub fn bytes_to_str(buf: &[u8]) -> &str {
17    match str::from_utf8(&buf) {
18        Ok(s) => s,
19        Err(_) => "",
20    }
21}
22
23// try to implement bytes.Index in Go
24pub fn bytes_index(buf: &[u8], subs: &[u8]) -> u32 {
25    let (len1, len2) = (buf.len(), subs.len());
26
27    if len2 == 0 {
28        return 0;
29    }
30    if len2 > len1 {
31        return u32::MAX;
32    }
33
34    for i in 0..=len1 - len2 {
35        if *subs == buf[i..i + len2] {
36            return i as u32;
37        }
38    }
39
40    u32::MAX
41}
42
43#[test]
44fn test_bytes_index() {
45    assert_eq!(0, bytes_index(b"abc", b""));
46    assert_eq!(0, bytes_index(b"abc", b"a"));
47    assert_eq!(u32::MAX, bytes_index(b"a", b"subs"));
48    assert_eq!(1, bytes_index(b"abc", b"b"));
49    assert_eq!(2, bytes_index(b"abcab", b"cab"));
50    assert_eq!(u32::MAX, bytes_index(b"abc", b"cd"));
51}
filetypes/types/utils/common.rs

filetypes/types/utils/
common.rs
