luaur_vm/functions/
buffer_readfp.rs

1use luaur_common::macros::luau_big_endian::LUAU_BIG_ENDIAN;
2
3use crate::functions::buffer_swapbe::buffer_swapbe;
4use crate::functions::lua_l_checkbuffer::lua_l_checkbuffer;
5use crate::functions::lua_l_checkinteger::lua_l_checkinteger;
6use crate::functions::lua_pushnumber::lua_pushnumber;
7use crate::macros::isoutofbounds::isoutofbounds;
8use crate::macros::lua_l_error::luaL_error;
9use crate::type_aliases::lua_state::lua_State;
10
11#[allow(non_snake_case)]
12pub unsafe fn buffer_readfp<T, StorageType>(L: *mut lua_State) -> core::ffi::c_int
13where
14    T: Copy + BufferReadableFloat,
15    StorageType: Copy,
16{
17    let mut len: usize = 0;
18    let buf = lua_l_checkbuffer(L, 1, &mut len) as *mut core::ffi::c_char;
19    let offset = lua_l_checkinteger(L, 2);
20
21    if isoutofbounds(offset, len, core::mem::size_of::<T>()) {
22        luaL_error!(L, "buffer access out of bounds");
23    }
24
25    let mut val: T = core::mem::zeroed();
26
27    if LUAU_BIG_ENDIAN {
28        static_assert_size::<T, StorageType>();
29        let mut tmp: StorageType = core::mem::zeroed();
30        core::ptr::copy_nonoverlapping(
31            buf.add(offset as usize),
32            &mut tmp as *mut StorageType as *mut core::ffi::c_char,
33            core::mem::size_of::<StorageType>(),
34        );
35        tmp = buffer_swapbe(tmp);
36        core::ptr::copy_nonoverlapping(
37            &tmp as *const StorageType as *const core::ffi::c_char,
38            &mut val as *mut T as *mut core::ffi::c_char,
39            core::mem::size_of::<T>(),
40        );
41    } else {
42        core::ptr::copy_nonoverlapping(
43            buf.add(offset as usize),
44            &mut val as *mut T as *mut core::ffi::c_char,
45            core::mem::size_of::<T>(),
46        );
47    }
48
49    lua_pushnumber(L, val.to_f64());
50    1
51}
52
53#[allow(dead_code)]
54fn static_assert_size<T, StorageType>() {
55    assert!(core::mem::size_of::<T>() == core::mem::size_of::<StorageType>());
56}
57
58pub trait BufferReadableFloat {
59    fn to_f64(self) -> f64;
60}
61
62impl BufferReadableFloat for f32 {
63    fn to_f64(self) -> f64 {
64        self as f64
65    }
66}
67
68impl BufferReadableFloat for f64 {
69    fn to_f64(self) -> f64 {
70        self
71    }
72}
luaur_vm/functions/buffer_readfp.rs

luaur_vm/functions/
buffer_readfp.rs
