term/terminfo/parser/
compiled.rs

1// Copyright 2019 The Rust Project Developers. See the COPYRIGHT
2// file at the top-level directory of this distribution and at
3// http://rust-lang.org/COPYRIGHT.
4//
5// Licensed under the Apache License, Version 2.0 <LICENSE-APACHE or
6// http://www.apache.org/licenses/LICENSE-2.0> or the MIT license
7// <LICENSE-MIT or http://opensource.org/licenses/MIT>, at your
8// option. This file may not be copied, modified, or distributed
9// except according to those terms.
10
11//! ncurses-compatible compiled terminfo format parsing (term(5))
12
13use std::collections::HashMap;
14use std::io;
15use std::io::prelude::*;
16
17use crate::terminfo::Error::*;
18use crate::terminfo::TermInfo;
19use crate::Result;
20
21pub use crate::terminfo::parser::names::*;
22
23// These are the orders ncurses uses in its compiled format (as of 5.9). Not
24// sure if portable.
25
26fn read_le_u16(r: &mut dyn io::Read) -> io::Result<u32> {
27    let mut buf = [0; 2];
28    r.read_exact(&mut buf)
29        .map(|()| u32::from(u16::from_le_bytes(buf)))
30}
31
32fn read_le_u32(r: &mut dyn io::Read) -> io::Result<u32> {
33    let mut buf = [0; 4];
34    r.read_exact(&mut buf).map(|()| u32::from_le_bytes(buf))
35}
36
37fn read_byte(r: &mut dyn io::Read) -> io::Result<u8> {
38    match r.bytes().next() {
39        Some(s) => s,
40        None => Err(io::Error::new(io::ErrorKind::Other, "end of file")),
41    }
42}
43
44/// Parse a compiled terminfo entry, using long capability names if `longnames`
45/// is true
46pub fn parse(file: &mut dyn io::Read, longnames: bool) -> Result<TermInfo> {
47    let (bnames, snames, nnames) = if longnames {
48        (boolfnames, stringfnames, numfnames)
49    } else {
50        (boolnames, stringnames, numnames)
51    };
52
53    // Check magic number
54    let mut buf = [0; 2];
55    file.read_exact(&mut buf)?;
56    let magic = u16::from_le_bytes(buf);
57
58    let read_number = match magic {
59        0x011A => read_le_u16,
60        0x021e => read_le_u32,
61        _ => return Err(BadMagic(magic).into()),
62    };
63
64    // According to the spec, these fields must be >= -1 where -1 means that the
65    // feature is not
66    // supported. Using 0 instead of -1 works because we skip sections with length
67    // 0.
68    macro_rules! read_nonneg {
69        () => {{
70            match read_le_u16(file)? as i16 {
71                n if n >= 0 => n as usize,
72                -1 => 0,
73                _ => return Err(InvalidLength.into()),
74            }
75        }};
76    }
77
78    let names_bytes = read_nonneg!();
79    let bools_bytes = read_nonneg!();
80    let numbers_count = read_nonneg!();
81    let string_offsets_count = read_nonneg!();
82    let string_table_bytes = read_nonneg!();
83
84    if names_bytes == 0 {
85        return Err(ShortNames.into());
86    }
87
88    if bools_bytes > boolnames.len() {
89        return Err(TooManyBools.into());
90    }
91
92    if numbers_count > numnames.len() {
93        return Err(TooManyNumbers.into());
94    }
95
96    if string_offsets_count > stringnames.len() {
97        return Err(TooManyStrings.into());
98    }
99
100    // don't read NUL
101    let mut bytes = Vec::new();
102    file.take((names_bytes - 1) as u64)
103        .read_to_end(&mut bytes)?;
104    let names_str = match String::from_utf8(bytes) {
105        Ok(s) => s,
106        Err(e) => return Err(NotUtf8(e.utf8_error()).into()),
107    };
108
109    let term_names: Vec<String> = names_str.split('|').map(|s| s.to_owned()).collect();
110    // consume NUL
111    if read_byte(file)? != b'\0' {
112        return Err(NamesMissingNull.into());
113    }
114
115    let bools_map = (0..bools_bytes)
116        .filter_map(|i| match read_byte(file) {
117            Err(e) => Some(Err(e)),
118            Ok(1) => Some(Ok((bnames[i], true))),
119            Ok(_) => None,
120        })
121        .collect::<io::Result<HashMap<_, _>>>()?;
122
123    if (bools_bytes + names_bytes) % 2 == 1 {
124        read_byte(file)?; // compensate for padding
125    }
126
127    let numbers_map = (0..numbers_count)
128        .filter_map(|i| match read_number(file) {
129            Ok(0xFFFF) => None,
130            Ok(n) => Some(Ok((nnames[i], n))),
131            Err(e) => Some(Err(e)),
132        })
133        .collect::<io::Result<HashMap<_, _>>>()?;
134
135    let string_map: HashMap<&str, Vec<u8>> = if string_offsets_count > 0 {
136        let string_offsets = (0..string_offsets_count)
137            .map(|_| {
138                let mut buf = [0; 2];
139                file.read_exact(&mut buf).map(|()| u16::from_le_bytes(buf))
140            })
141            .collect::<io::Result<Vec<_>>>()?;
142
143        let mut string_table = Vec::new();
144        file.take(string_table_bytes as u64)
145            .read_to_end(&mut string_table)?;
146
147        string_offsets
148            .into_iter()
149            .enumerate()
150            .filter(|&(_, offset)| {
151                // non-entry
152                offset != 0xFFFF
153            })
154            .map(|(i, offset)| {
155                let offset = offset as usize;
156
157                let name = if snames[i] == "_" {
158                    stringfnames[i]
159                } else {
160                    snames[i]
161                };
162
163                if offset == 0xFFFE {
164                    // undocumented: FFFE indicates cap@, which means the capability
165                    // is not present
166                    // unsure if the handling for this is correct
167                    return Ok((name, Vec::new()));
168                }
169
170                // Find the offset of the NUL we want to go to
171                let nulpos = string_table[offset..string_table_bytes]
172                    .iter()
173                    .position(|&b| b == 0);
174                match nulpos {
175                    Some(len) => Ok((name, string_table[offset..offset + len].to_vec())),
176                    None => Err(crate::Error::TerminfoParsing(StringsMissingNull)),
177                }
178            })
179            .collect::<Result<HashMap<_, _>>>()?
180    } else {
181        HashMap::new()
182    };
183
184    // And that's all there is to it
185    Ok(TermInfo {
186        names: term_names,
187        bools: bools_map,
188        numbers: numbers_map,
189        strings: string_map,
190    })
191}
192
193#[cfg(test)]
194mod test {
195
196    use super::{boolfnames, boolnames, numfnames, numnames, stringfnames, stringnames};
197
198    #[test]
199    fn test_veclens() {
200        assert_eq!(boolfnames.len(), boolnames.len());
201        assert_eq!(numfnames.len(), numnames.len());
202        assert_eq!(stringfnames.len(), stringnames.len());
203    }
204}
term/terminfo/parser/compiled.rs

term/terminfo/parser/
compiled.rs
