Files
winit/src/platform/linux/x11/util/format.rs
2018-07-02 11:05:25 -04:00

59 lines
2.0 KiB
Rust

use std::fmt::Debug;
use std::mem;
use std::os::raw::*;
// This isn't actually the number of the bits in the format.
// X11 does a match on this value to determine which type to call sizeof on.
// Thus, we use 32 for c_long, since 32 maps to c_long which maps to 64.
// ...if that sounds confusing, then you know why this enum is here.
#[derive(Debug, Copy, Clone, PartialEq, Eq, PartialOrd, Ord)]
pub enum Format {
Char = 8,
Short = 16,
Long = 32,
}
impl Format {
pub fn from_format(format: usize) -> Option<Self> {
match format {
8 => Some(Format::Char),
16 => Some(Format::Short),
32 => Some(Format::Long),
_ => None,
}
}
pub fn is_same_size_as<T>(&self) -> bool {
mem::size_of::<T>() == self.get_actual_size()
}
pub fn get_actual_size(&self) -> usize {
match self {
&Format::Char => mem::size_of::<c_char>(),
&Format::Short => mem::size_of::<c_short>(),
&Format::Long => mem::size_of::<c_long>(),
}
}
pub fn get_payload_size(&self) -> usize {
match self {
// Due to the wonders of X11, half the space goes unused if you're not using longs (on 64-bit).
&Format::Char => mem::size_of::<c_char>() * 20,
&Format::Short => mem::size_of::<c_short>() * 10,
&Format::Long => mem::size_of::<c_long>() * 5,
}
}
}
pub trait Formattable: Debug + Clone + Copy + PartialEq + PartialOrd {
const FORMAT: Format;
}
// You might be surprised by the absence of c_int, but not as surprised as X11 would be by the presence of it.
impl Formattable for c_schar { const FORMAT: Format = Format::Char; }
impl Formattable for c_uchar { const FORMAT: Format = Format::Char; }
impl Formattable for c_short { const FORMAT: Format = Format::Short; }
impl Formattable for c_ushort { const FORMAT: Format = Format::Short; }
impl Formattable for c_long { const FORMAT: Format = Format::Long; }
impl Formattable for c_ulong { const FORMAT: Format = Format::Long; }