serde_yaml/libyaml/
cstr.rs

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1use std::fmt::{self, Debug, Display, Write as _};
2use std::marker::PhantomData;
3use std::ptr::NonNull;
4use std::slice;
5use std::str;
6
7#[derive(Copy, Clone)]
8pub(crate) struct CStr<'a> {
9    ptr: NonNull<u8>,
10    marker: PhantomData<&'a [u8]>,
11}
12
13unsafe impl<'a> Send for CStr<'a> {}
14unsafe impl<'a> Sync for CStr<'a> {}
15
16impl<'a> CStr<'a> {
17    pub fn from_bytes_with_nul(bytes: &'static [u8]) -> Self {
18        assert_eq!(bytes.last(), Some(&b'\0'));
19        let ptr = NonNull::from(bytes).cast();
20        unsafe { Self::from_ptr(ptr) }
21    }
22
23    pub unsafe fn from_ptr(ptr: NonNull<i8>) -> Self {
24        CStr {
25            ptr: ptr.cast(),
26            marker: PhantomData,
27        }
28    }
29
30    pub fn len(self) -> usize {
31        let start = self.ptr.as_ptr();
32        let mut end = start;
33        unsafe {
34            while *end != 0 {
35                end = end.add(1);
36            }
37            end.offset_from(start) as usize
38        }
39    }
40
41    pub fn to_bytes(self) -> &'a [u8] {
42        let len = self.len();
43        unsafe { slice::from_raw_parts(self.ptr.as_ptr(), len) }
44    }
45}
46
47impl<'a> Display for CStr<'a> {
48    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
49        let ptr = self.ptr.as_ptr();
50        let len = self.len();
51        let bytes = unsafe { slice::from_raw_parts(ptr, len) };
52        display_lossy(bytes, formatter)
53    }
54}
55
56impl<'a> Debug for CStr<'a> {
57    fn fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result {
58        let ptr = self.ptr.as_ptr();
59        let len = self.len();
60        let bytes = unsafe { slice::from_raw_parts(ptr, len) };
61        debug_lossy(bytes, formatter)
62    }
63}
64
65fn display_lossy(mut bytes: &[u8], formatter: &mut fmt::Formatter) -> fmt::Result {
66    loop {
67        match str::from_utf8(bytes) {
68            Ok(valid) => return formatter.write_str(valid),
69            Err(utf8_error) => {
70                let valid_up_to = utf8_error.valid_up_to();
71                let valid = unsafe { str::from_utf8_unchecked(&bytes[..valid_up_to]) };
72                formatter.write_str(valid)?;
73                formatter.write_char(char::REPLACEMENT_CHARACTER)?;
74                if let Some(error_len) = utf8_error.error_len() {
75                    bytes = &bytes[valid_up_to + error_len..];
76                } else {
77                    return Ok(());
78                }
79            }
80        }
81    }
82}
83
84pub(crate) fn debug_lossy(mut bytes: &[u8], formatter: &mut fmt::Formatter) -> fmt::Result {
85    formatter.write_char('"')?;
86
87    while !bytes.is_empty() {
88        let from_utf8_result = str::from_utf8(bytes);
89        let valid = match from_utf8_result {
90            Ok(valid) => valid,
91            Err(utf8_error) => {
92                let valid_up_to = utf8_error.valid_up_to();
93                unsafe { str::from_utf8_unchecked(&bytes[..valid_up_to]) }
94            }
95        };
96
97        let mut written = 0;
98        for (i, ch) in valid.char_indices() {
99            let esc = ch.escape_debug();
100            if esc.len() != 1 && ch != '\'' {
101                formatter.write_str(&valid[written..i])?;
102                for ch in esc {
103                    formatter.write_char(ch)?;
104                }
105                written = i + ch.len_utf8();
106            }
107        }
108        formatter.write_str(&valid[written..])?;
109
110        match from_utf8_result {
111            Ok(_valid) => break,
112            Err(utf8_error) => {
113                let end_of_broken = if let Some(error_len) = utf8_error.error_len() {
114                    valid.len() + error_len
115                } else {
116                    bytes.len()
117                };
118                for b in &bytes[valid.len()..end_of_broken] {
119                    write!(formatter, "\\x{:02x}", b)?;
120                }
121                bytes = &bytes[end_of_broken..];
122            }
123        }
124    }
125
126    formatter.write_char('"')
127}
serde_yaml/libyaml/cstr.rs

serde_yaml/libyaml/
cstr.rs
