1use crate::{DeserializeErr, DeserializeResult};
2use alloc::string::String;
3
4pub fn take(amount: usize, data: &[u8]) -> DeserializeResult<&[u8]> {
5 if data.len() < amount {
6 Err(DeserializeErr::Eof)
7 } else {
8 Ok(data.split_at(amount).into())
9 }
10}
11
12pub fn hex(data: &[u8]) -> String {
13 let mut str = String::with_capacity(data.len() * 2);
14 for byte_ref in data {
15 let byte = *byte_ref;
16 str.push(hex_char_for(byte >> 4));
17 str.push(hex_char_for(byte & 0xF));
18 }
19 str
20}
21
22const ZERO_ASCII_CODE: u8 = 48;
23const LOWER_A_ASCII_CODE: u8 = 97;
24
25fn hex_char_for(half: u8) -> char {
26 if half > 0xF {
27 panic!("not defined for > 0xF (operates on half a byte)");
28 }
29
30 if half < 10 {
31 (half + ZERO_ASCII_CODE) as char
32 } else {
33 (half + (LOWER_A_ASCII_CODE - 10)) as char
34 }
35}
36
37pub fn parse_hex_char(data: u8) -> Option<u8> {
38 const UPPER_A_ASCII_CODE: u8 = 65;
39 const LOWER_F_ASCII_CODE: u8 = 102;
40 const UPPER_F_ASCII_CODE: u8 = 70;
41 const NINE_ASCII_CODE: u8 = 57;
42
43 if data >= LOWER_A_ASCII_CODE {
44 if data > LOWER_F_ASCII_CODE {
45 None
46 } else {
47 Some(10 + (data - LOWER_A_ASCII_CODE))
48 }
49 } else if data >= UPPER_A_ASCII_CODE {
50 if data > UPPER_F_ASCII_CODE {
51 None
52 } else {
53 Some(10 + (data - UPPER_A_ASCII_CODE))
54 }
55 } else if data >= ZERO_ASCII_CODE {
56 if data > NINE_ASCII_CODE {
57 None
58 } else {
59 Some(data - ZERO_ASCII_CODE)
60 }
61 } else {
62 None
63 }
64}