libgm 0.5.0

A tool for modding, unpacking and decompiling GameMaker games
Documentation 
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use crate::prelude::*;
use crate::wad::data::Endianness;
use crate::wad::deserialize::reader::DataReader;

macro_rules! read_int_fn {
    ($method:ident, $dtype:ty) => {
        /// Read an integer from the data file while advancing the data position.
        /// Respects the endianness setting.
        pub fn $method(&mut self) -> Result<$dtype> {
            let bytes = *self
                .read_bytes_const()
                .with_context(|| format!("reading {} integer", stringify!($dtype)))?;
            Ok(match self.endianness {
                Endianness::Little => <$dtype>::from_le_bytes(bytes),
                Endianness::Big => <$dtype>::from_be_bytes(bytes),
            })
        }
    };
}

impl DataReader<'_> {
    read_int_fn!(read_u64, u64);

    read_int_fn!(read_u32, u32);

    read_int_fn!(read_u16, u16);

    read_int_fn!(read_u8, u8);

    read_int_fn!(read_i64, i64);

    read_int_fn!(read_i32, i32);

    read_int_fn!(read_i16, i16);

    read_int_fn!(read_i8, i8);

    read_int_fn!(read_f64, f64);

    read_int_fn!(read_f32, f32);

    /// Read an unsigned 32-bit integer from the data file while advancing the
    /// data position. Returns zero if the read number is -1 or 0.
    pub fn read_count(&mut self, purpose: &'static str) -> Result<u32> {
        match self.read_i32()? {
            -1 => Ok(0),
            n if n >= 0 => Ok(n as u32),
            n => bail!("Negative {purpose} count {n} (0x{n:08X})"),
        }
    }
}