cv_bridge/utils/
image_byteorder_ops.rs

1//! This module contains functions to convert between big and little endian byte order.
2use std::io::Cursor;
3use byteorder::{
4    LittleEndian,
5    BigEndian,
6    ReadBytesExt,
7    WriteBytesExt
8};
9
10/// Takes a u8 array and constructs a u16 array by converting
11/// two u8 values into one u16 value.
12/// 
13/// ## Arguments
14/// * `data` - The u8 array to convert.
15/// * `big_endian` - If true, the u8 array is in big endian byte order.
16///                 If false, the u8 array is in little endian byte order.
17/// 
18/// ## Returns
19/// A u16 array.
20pub fn from_u8_to_u16(data: &[u8], big_endian: bool) -> Vec<u16> {
21    let mut data16 = Vec::with_capacity(data.len());
22    let mut cursor = Cursor::new(data);
23
24    if big_endian {
25        while let Ok(value) = cursor.read_u16::<BigEndian>() {
26            data16.push(value);
27        }
28    } else {
29        while let Ok(value) = cursor.read_u16::<LittleEndian>() {
30            data16.push(value);
31        }
32    }
33
34    data16
35}
36
37/// Takes a u16 array and constructs a u8 array by converting
38/// one u16 value into two u8 values.
39/// 
40/// ## Arguments
41/// * `data` - The u16 array to convert.
42/// * `big_endian` - If true, the u8 array will be in big endian byte order.
43///                If false, the u8 array will be in little endian byte order.
44/// 
45/// ## Returns
46/// A u8 array.
47pub fn from_u16_to_u8(data: &[u16], big_endian: bool) -> Vec<u8> {
48    let mut data8 = Vec::with_capacity(data.len());
49
50    if big_endian {
51        for value in data {
52            data8.write_u16::<BigEndian>(*value).unwrap();
53        }
54    } else {
55        for value in data {
56            data8.write_u16::<LittleEndian>(*value).unwrap();
57        }
58    }
59
60    data8
61}
62
63/// Takes a u8 array in big endian byte order and converts it to little endian byte order.
64/// 
65/// ## Arguments
66/// * `be` - The u8 array to convert.
67/// 
68/// ## Returns
69/// A u8 array in little endian byte order.
70pub fn from_be_to_le(be: &[u8]) -> Vec<u8> {
71    let mut le = Vec::with_capacity(be.len());
72    let mut cursor = Cursor::new(be);
73
74    while let Ok(value) = cursor.read_u16::<BigEndian>() {
75        le.write_u16::<LittleEndian>(value).unwrap();
76    }
77
78    le
79}
80
81/// Takes a u8 array in little endian byte order and converts it to big endian byte order.
82/// 
83/// ## Arguments
84/// * `le` - The u8 array to convert.
85/// 
86/// ## Returns
87/// A u8 array in big endian byte order.
88pub fn from_le_to_be(le: &[u8]) -> Vec<u8> {
89    let mut be = Vec::with_capacity(le.len());
90    let mut cursor = Cursor::new(le);
91
92    while let Ok(value) = cursor.read_u16::<LittleEndian>() {
93        be.write_u16::<BigEndian>(value).unwrap();
94    }
95
96    be
97}
cv_bridge/utils/image_byteorder_ops.rs

cv_bridge/utils/
image_byteorder_ops.rs
