rgbds_obj/
symbol.rs

1use crate::util::{opt_u32, read_str, read_u32le, read_u8};
2use std::fmt::{self, Display, Formatter};
3use std::io::{self, Read};
4
5/// A symbol declaration, which may include a definition.
6#[derive(Debug)]
7pub struct Symbol {
8    name: Vec<u8>,
9    visibility: SymbolVisibility,
10}
11impl Symbol {
12    pub(crate) fn read_from(mut input: impl Read) -> Result<Self, io::Error> {
13        let name = read_str(&mut input)?;
14        let visibility = SymbolVisibility::read_from(input)?;
15        Ok(Self { name, visibility })
16    }
17
18    /// The symbol's name, as stored raw in the object file.
19    /// Like all names pulled from object files, this is not guaranteed to be valid UTF-8.
20    pub fn name(&self) -> &[u8] {
21        &self.name
22    }
23
24    /// The symbol's visibility, including its definition data (if any).
25    pub fn visibility(&self) -> &SymbolVisibility {
26        &self.visibility
27    }
28}
29
30/// A symbol's visibility, and accompanying data if applicable.
31#[derive(Debug)]
32pub enum SymbolVisibility {
33    /// The symbol is defined in this object file, but is not visible outside of it.
34    Local(SymbolDef),
35    /// The symbol is not defined in this object file.
36    Imported,
37    /// The symbol is defined in this object file, and is visible in others as well.
38    Exported(SymbolDef),
39}
40impl SymbolVisibility {
41    fn read_from(mut input: impl Read) -> Result<Self, io::Error> {
42        use SymbolVisibility::*;
43
44        match read_u8(&mut input)? {
45            0 => Ok(Local(SymbolDef::read_from(input)?)),
46            1 => Ok(Imported),
47            2 => Ok(Exported(SymbolDef::read_from(input)?)),
48            _ => Err(io::Error::new(
49                io::ErrorKind::InvalidData,
50                "Invalid symbol visibility type",
51            )),
52        }
53    }
54
55    /// The symbol visibility's name.
56    pub fn name(&self) -> &'static str {
57        use SymbolVisibility::*;
58
59        match self {
60            Local(..) => "local",
61            Imported => "import",
62            Exported(..) => "export",
63        }
64    }
65
66    /// Returns the symbol's definition data, if any.
67    pub fn data(&self) -> Option<&SymbolDef> {
68        use SymbolVisibility::*;
69
70        match self {
71            Local(data) | Exported(data) => Some(data),
72            Imported => None,
73        }
74    }
75}
76impl Display for SymbolVisibility {
77    fn fmt(&self, fmt: &mut Formatter) -> Result<(), fmt::Error> {
78        write!(fmt, "{}", self.name())
79    }
80}
81
82/// A symbol definition's data.
83#[derive(Debug)]
84pub struct SymbolDef {
85    source_file_id: u32,
86    line_no: u32,
87    section_id: Option<u32>,
88    value: u32,
89}
90impl SymbolDef {
91    fn read_from(mut input: impl Read) -> Result<Self, io::Error> {
92        let source_file_id = read_u32le(&mut input)?;
93        let line_no = read_u32le(&mut input)?;
94        let section_id = opt_u32(read_u32le(&mut input)?);
95        let value = read_u32le(input)?;
96
97        Ok(Self {
98            source_file_id,
99            line_no,
100            section_id,
101            value,
102        })
103    }
104
105    /// Where the symbol has been defined.
106    /// That is, the [file stack node][crate::Node] ID, and the line number.
107    pub fn source(&self) -> (u32, u32) {
108        (self.source_file_id, self.line_no)
109    }
110
111    /// The ID of the [`Section`][crate::Section] the symbol was defined in.
112    /// This is `None` for constants.
113    pub fn section(&self) -> Option<u32> {
114        self.section_id
115    }
116
117    /// The symbol's offset within its [`Section`][crate::Section], or its value if not attached to one.
118    pub fn value(&self) -> u32 {
119        self.value
120    }
121}
rgbds_obj/symbol.rs

rgbds_obj/
symbol.rs
