lexical_util/
ascii.rs

1//! Utilities for working with ASCII characters.
2
3/// Determine if a character is a valid ASCII character for float grammar.
4pub const fn is_valid_ascii(c: u8) -> bool {
5    // Below 0x20 is mostly control characters, with no representation.
6    // 0x7F is a control character, DEL, so don't include it.
7    // We also want the few visual characters below 0x20:
8    //  0x09 - Horizontal Tab
9    //  0x0A - Newline
10    //  0x0B - Vertical Tab (Deprecated)
11    //  0x0C - Form Feed (Deprecated)
12    //  0x0D - Carriage Return
13    (c >= 0x09 && c <= 0x0d) || (c >= 0x20 && c < 0x7F)
14}
15
16/// Determine if a slice is all valid ASCII characters for float grammar.
17/// Modified to be used in a const fn, since for loops and iter don't work.
18pub const fn is_valid_ascii_slice(slc: &[u8]) -> bool {
19    let mut index = 0;
20    while index < slc.len() {
21        if !is_valid_ascii(slc[index]) {
22            return false;
23        }
24        index += 1;
25    }
26    true
27}
28
29/// Determine if a character is a valid ASCII letter.
30pub const fn is_valid_letter(c: u8) -> bool {
31    (c >= 0x41 && c <= 0x5a) || (c >= 0x61 && c <= 0x7a)
32}
33
34/// Determine if a slice is all valid ASCII letters.
35/// Modified to be used in a const fn, since for loops and iter don't work.
36pub const fn is_valid_letter_slice(slc: &[u8]) -> bool {
37    let mut index = 0;
38    while index < slc.len() {
39        if !is_valid_letter(slc[index]) {
40            return false;
41        }
42        index += 1;
43    }
44    true
45}
lexical_util/ascii.rs

lexical_util/
ascii.rs
