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Diffstat (limited to 'vendor/gimli/src/endianity.rs')
| -rw-r--r-- | vendor/gimli/src/endianity.rs | 256 |
1 files changed, 256 insertions, 0 deletions
diff --git a/vendor/gimli/src/endianity.rs b/vendor/gimli/src/endianity.rs new file mode 100644 index 000000000..3201551f1 --- /dev/null +++ b/vendor/gimli/src/endianity.rs @@ -0,0 +1,256 @@ +//! Types for compile-time and run-time endianity. + +use core::convert::TryInto; +use core::fmt::Debug; + +/// A trait describing the endianity of some buffer. +pub trait Endianity: Debug + Default + Clone + Copy + PartialEq + Eq { + /// Return true for big endian byte order. + fn is_big_endian(self) -> bool; + + /// Return true for little endian byte order. + #[inline] + fn is_little_endian(self) -> bool { + !self.is_big_endian() + } + + /// Reads an unsigned 16 bit integer from `buf`. + /// + /// # Panics + /// + /// Panics when `buf.len() < 2`. + #[inline] + fn read_u16(self, buf: &[u8]) -> u16 { + let bytes: &[u8; 2] = buf[..2].try_into().unwrap(); + if self.is_big_endian() { + u16::from_be_bytes(*bytes) + } else { + u16::from_le_bytes(*bytes) + } + } + + /// Reads an unsigned 32 bit integer from `buf`. + /// + /// # Panics + /// + /// Panics when `buf.len() < 4`. + #[inline] + fn read_u32(self, buf: &[u8]) -> u32 { + let bytes: &[u8; 4] = buf[..4].try_into().unwrap(); + if self.is_big_endian() { + u32::from_be_bytes(*bytes) + } else { + u32::from_le_bytes(*bytes) + } + } + + /// Reads an unsigned 64 bit integer from `buf`. + /// + /// # Panics + /// + /// Panics when `buf.len() < 8`. + #[inline] + fn read_u64(self, buf: &[u8]) -> u64 { + let bytes: &[u8; 8] = buf[..8].try_into().unwrap(); + if self.is_big_endian() { + u64::from_be_bytes(*bytes) + } else { + u64::from_le_bytes(*bytes) + } + } + + /// Read an unsigned n-bytes integer u64. + /// + /// # Panics + /// + /// Panics when `buf.len() < 1` or `buf.len() > 8`. + #[inline] + fn read_uint(&mut self, buf: &[u8]) -> u64 { + let mut tmp = [0; 8]; + if self.is_big_endian() { + tmp[8 - buf.len()..].copy_from_slice(buf); + } else { + tmp[..buf.len()].copy_from_slice(buf); + } + self.read_u64(&tmp) + } + + /// Reads a signed 16 bit integer from `buf`. + /// + /// # Panics + /// + /// Panics when `buf.len() < 2`. + #[inline] + fn read_i16(self, buf: &[u8]) -> i16 { + self.read_u16(buf) as i16 + } + + /// Reads a signed 32 bit integer from `buf`. + /// + /// # Panics + /// + /// Panics when `buf.len() < 4`. + #[inline] + fn read_i32(self, buf: &[u8]) -> i32 { + self.read_u32(buf) as i32 + } + + /// Reads a signed 64 bit integer from `buf`. + /// + /// # Panics + /// + /// Panics when `buf.len() < 8`. + #[inline] + fn read_i64(self, buf: &[u8]) -> i64 { + self.read_u64(buf) as i64 + } + + /// Reads a 32 bit floating point number from `buf`. + /// + /// # Panics + /// + /// Panics when `buf.len() < 8`. + #[inline] + fn read_f32(self, buf: &[u8]) -> f32 { + f32::from_bits(self.read_u32(buf)) + } + + /// Reads a 32 bit floating point number from `buf`. + /// + /// # Panics + /// + /// Panics when `buf.len() < 8`. + #[inline] + fn read_f64(self, buf: &[u8]) -> f64 { + f64::from_bits(self.read_u64(buf)) + } + + /// Writes an unsigned 16 bit integer `n` to `buf`. + /// + /// # Panics + /// + /// Panics when `buf.len() < 2`. + #[inline] + fn write_u16(self, buf: &mut [u8], n: u16) { + let bytes = if self.is_big_endian() { + n.to_be_bytes() + } else { + n.to_le_bytes() + }; + buf[..2].copy_from_slice(&bytes); + } + + /// Writes an unsigned 32 bit integer `n` to `buf`. + /// + /// # Panics + /// + /// Panics when `buf.len() < 4`. + #[inline] + fn write_u32(self, buf: &mut [u8], n: u32) { + let bytes = if self.is_big_endian() { + n.to_be_bytes() + } else { + n.to_le_bytes() + }; + buf[..4].copy_from_slice(&bytes); + } + + /// Writes an unsigned 64 bit integer `n` to `buf`. + /// + /// # Panics + /// + /// Panics when `buf.len() < 8`. + #[inline] + fn write_u64(self, buf: &mut [u8], n: u64) { + let bytes = if self.is_big_endian() { + n.to_be_bytes() + } else { + n.to_le_bytes() + }; + buf[..8].copy_from_slice(&bytes); + } +} + +/// Byte order that is selectable at runtime. +#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)] +pub enum RunTimeEndian { + /// Little endian byte order. + Little, + /// Big endian byte order. + Big, +} + +impl Default for RunTimeEndian { + #[cfg(target_endian = "little")] + #[inline] + fn default() -> RunTimeEndian { + RunTimeEndian::Little + } + + #[cfg(target_endian = "big")] + #[inline] + fn default() -> RunTimeEndian { + RunTimeEndian::Big + } +} + +impl Endianity for RunTimeEndian { + #[inline] + fn is_big_endian(self) -> bool { + self != RunTimeEndian::Little + } +} + +/// Little endian byte order. +#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)] +pub struct LittleEndian; + +impl Default for LittleEndian { + #[inline] + fn default() -> LittleEndian { + LittleEndian + } +} + +impl Endianity for LittleEndian { + #[inline] + fn is_big_endian(self) -> bool { + false + } +} + +/// Big endian byte order. +#[derive(Debug, Clone, Copy, PartialEq, Eq, Hash)] +pub struct BigEndian; + +impl Default for BigEndian { + #[inline] + fn default() -> BigEndian { + BigEndian + } +} + +impl Endianity for BigEndian { + #[inline] + fn is_big_endian(self) -> bool { + true + } +} + +/// The native endianity for the target platform. +#[cfg(target_endian = "little")] +pub type NativeEndian = LittleEndian; + +#[cfg(target_endian = "little")] +#[allow(non_upper_case_globals)] +#[doc(hidden)] +pub const NativeEndian: LittleEndian = LittleEndian; + +/// The native endianity for the target platform. +#[cfg(target_endian = "big")] +pub type NativeEndian = BigEndian; + +#[cfg(target_endian = "big")] +#[allow(non_upper_case_globals)] +#[doc(hidden)] +pub const NativeEndian: BigEndian = BigEndian; 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