1 use std::fmt::{self, Debug, Display, Write as _};
2 use std::marker::PhantomData;
3 use std::ptr::NonNull;
4 use std::slice;
5 use std::str;
6
7 #[derive(Copy, Clone)]
8 pub(crate) struct CStr<'a> {
9 ptr: NonNull<u8>,
10 marker: PhantomData<&'a [u8]>,
11 }
12
13 unsafe impl<'a> Send for CStr<'a> {}
14 unsafe impl<'a> Sync for CStr<'a> {}
15
16 impl<'a> CStr<'a> {
from_bytes_with_nul(bytes: &'static [u8]) -> Self17 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
from_ptr(ptr: NonNull<i8>) -> Self23 pub unsafe fn from_ptr(ptr: NonNull<i8>) -> Self {
24 CStr {
25 ptr: ptr.cast(),
26 marker: PhantomData,
27 }
28 }
29
len(self) -> usize30 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
to_bytes(self) -> &'a [u8]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
47 impl<'a> Display for CStr<'a> {
fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result48 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
56 impl<'a> Debug for CStr<'a> {
fmt(&self, formatter: &mut fmt::Formatter) -> fmt::Result57 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
display_lossy(mut bytes: &[u8], formatter: &mut fmt::Formatter) -> fmt::Result65 fn 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
debug_lossy(mut bytes: &[u8], formatter: &mut fmt::Formatter) -> fmt::Result84 pub(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 }
128