82 lines
2.1 KiB
Markdown
82 lines
2.1 KiB
Markdown
bytecheck is a type validation framework for Rust.
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## bytecheck in action
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```rust
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use bytecheck::CheckBytes;
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#[derive(CheckBytes, Debug)]
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struct Test {
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a: u32,
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b: bool,
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c: char,
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}
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#[repr(C, align(16))]
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struct Aligned<const N: usize>([u8; N]);
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macro_rules! bytes {
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($($byte:literal,)*) => {
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(&Aligned([$($byte,)*]).0 as &[u8]).as_ptr()
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};
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($($byte:literal),*) => {
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bytes!($($byte,)*)
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};
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}
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fn main() {
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// This type is laid out as (u32, char, bool)
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unsafe {
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// These are valid bytes for (0, 'x', true)
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Test::check_bytes(
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bytes![
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0u8, 0u8, 0u8, 0u8, 0x78u8, 0u8, 0u8, 0u8,
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1u8, 255u8, 255u8, 255u8, 255u8, 255u8, 255u8, 255u8
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].cast(),
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&()
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).unwrap();
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// Changing the bytes for the u32 is OK, any bytes are a valid u32
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Test::check_bytes(
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bytes![
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42u8, 16u8, 20u8, 3u8, 0x78u8, 0u8, 0u8, 0u8,
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1u8, 255u8, 255u8, 255u8, 255u8, 255u8, 255u8, 255u8
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].cast(),
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&()
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).unwrap();
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// Characters outside the valid ranges are invalid
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Test::check_bytes(
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bytes![
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0u8, 0u8, 0u8, 0u8, 0x00u8, 0xd8u8, 0u8, 0u8,
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1u8, 255u8, 255u8, 255u8, 255u8, 255u8, 255u8, 255u8
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].cast(),
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&()
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).unwrap_err();
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Test::check_bytes(
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bytes![
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0u8, 0u8, 0u8, 0u8, 0x00u8, 0x00u8, 0x11u8, 0u8,
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1u8, 255u8, 255u8, 255u8, 255u8, 255u8, 255u8, 255u8
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].cast(),
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&()
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).unwrap_err();
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// 0 is a valid boolean value (false) but 2 is not
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Test::check_bytes(
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bytes![
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0u8, 0u8, 0u8, 0u8, 0x78u8, 0u8, 0u8, 0u8,
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0u8, 255u8, 255u8, 255u8, 255u8, 255u8, 255u8, 255u8
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].cast(),
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&()
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).unwrap();
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Test::check_bytes(
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bytes![
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0u8, 0u8, 0u8, 0u8, 0x78u8, 0u8, 0u8, 0u8,
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2u8, 255u8, 255u8, 255u8, 255u8, 255u8, 255u8, 255u8
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].cast(),
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&()
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).unwrap_err();
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}
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}
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```
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