~jojo/Carth

ref: c18ff977c6e198a4222590236d1c8d0e2ab8ab8a Carth/foreign-core/src/lib.rs -rw-r--r-- 3.0 KiB
c18ff977JoJo Update std with undefined & panic functionality 1 year, 7 months ago
                                                                                
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
#![feature(const_fn)]

use std::io::{self, Write};
use std::{alloc, ptr, slice, str};

macro_rules! def_carth_closure {
    ($e:expr, $s:ident, $f:ident; $ta:ty, $tr:ty; $a:pat => $b:expr) => {
        #[export_name = $e]
        pub static $s: Closure<$ta, $tr> = Closure::new($f);
        pub extern "C" fn $f(_: Captures, $a: $ta) -> $tr {
            $b
        }
    };
}

pub type Captures = *const ();
pub type ClosureFunc<A, B> = extern "C" fn(Captures, A) -> B;

#[repr(C)]
pub struct Closure<A, B> {
    captures: Captures,
    func: ClosureFunc<A, B>,
}

unsafe impl<A, B> Sync for Closure<A, B> {}

impl<A, B> Closure<A, B> {
    const fn new(f: ClosureFunc<A, B>) -> Closure<A, B> {
        Closure {
            captures: ptr::null(),
            func: f,
        }
    }
}

#[repr(C)]
pub struct Array<A> {
    elems: *mut A,
    len: u64,
}

impl<A> Array<A> {
    fn new(xs: Vec<A>) -> Array<A> {
        let len = xs.len() as u64;
        Array {
            elems: Box::into_raw(xs.into_boxed_slice()) as *mut A,
            len,
        }
    }
}

#[repr(C)]
pub struct Str {
    array: Array<u8>,
}

impl Str {
    fn new(s: String) -> Str {
        Str {
            array: Array::new(s.into_bytes()),
        }
    }
}

#[repr(C)]
pub struct Pair<A, B> {
    fst: A,
    snd: B,
}

// TODO: Do it properly.
//       https://en.cppreference.com/w/c/types/max_align_t
const MAX_ALIGN: usize = 8;

#[no_mangle]
pub extern "C" fn carth_alloc(size: u64) -> *mut u8 {
    unsafe { alloc::alloc(alloc::Layout::from_size_align(size as usize, MAX_ALIGN).unwrap()) }
}

def_carth_closure! {
    "display-inline", DISPLAY_INLINE, display_inline;
    Str, (); s => {
        let s = from_carth_str(&s);
        print!("{}", s);
        io::stdout().flush().ok();
    }
}

def_carth_closure! {
    "-str-append", STR_APPEND, str_append;
    Pair<Str, Str>, Str; Pair { fst, snd } => {
        let (s1, s2) = (from_carth_str(&fst), from_carth_str(&snd));
        Str::new(s1.to_string() + s2)
    }
}

fn from_carth_str<'s>(s: &'s Str) -> &'s str {
    unsafe {
        let Array { elems, len } = s.array;
        let slice = slice::from_raw_parts(elems, len as usize);
        str::from_utf8_unchecked(slice)
    }
}

def_carth_closure! {
    "add-int", ADD_INT, add_int;
    Pair<i64, i64>, i64; Pair { fst, snd } => fst + snd
}

def_carth_closure! {
    "sub-int", SUB_INT, sub_int;
    Pair<i64, i64>, i64; Pair { fst, snd } => fst - snd
}

def_carth_closure! {
    "rem-int", REM_INT, rem_int;
    Pair<i64, i64>, i64; Pair { fst, snd } => fst % snd
}

def_carth_closure! {
    "gt-int", GT_INT, gt_int;
    Pair<i64, i64>, bool; Pair { fst, snd } => fst > snd
}

def_carth_closure! {
    "eq-int", EQ_INT, eq_int;
    Pair<i64, i64>, bool; Pair { fst, snd } => fst == snd
}

def_carth_closure! {
    "show-int", SHOW_INT, show_int;
    i64, Str; n =>
        Str::new(n.to_string())
}

def_carth_closure! {
    "-panic", PANIC, panic;
    Str, (); s => {
        eprintln!("*** Panic: {}", from_carth_str(&s));
        std::process::abort()
    }
}