diff options
| -rw-r--r-- | src/reader.rs | 344 |
1 files changed, 174 insertions, 170 deletions
diff --git a/src/reader.rs b/src/reader.rs index c5dacf6..b263f22 100644 --- a/src/reader.rs +++ b/src/reader.rs @@ -39,6 +39,16 @@ impl<'a> U8Reader<'a> { } } +/* a `std::io::Read`-friendly `Reader` would take some thought. this was an old impl, and now would + * require something like + * ``` + * pub struct IoReader<'io, T: std::io::Read> { + * io: &io mut T, + * count: u64, + * start: u64, + * } + * ``` + */ /* #[cfg(feature = "std")] impl<T: std::io::Read> Reader<u8> for T { @@ -55,207 +65,201 @@ impl<T: std::io::Read> Reader<u8> for T { } */ -impl Reader<u64, u8> for U8Reader<'_> { - #[inline] - fn next(&mut self) -> Result<u8, ReadError> { - if self.data == self.end { - Err(ReadError::ExhaustedInput) - } else { - let word = unsafe { core::ptr::read(self.data) }; - unsafe { - self.data = self.data.offset(1); +macro_rules! word_wrapper { + ($name:ident, $underlying:ident) => { + #[derive(Debug, PartialEq, Eq, Hash, PartialOrd, Ord, Copy, Clone)] + pub struct $name(pub $underlying); + + impl core::fmt::Display for $name { + fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result { + write!(f, "{}", self.0) } - Ok(word) } } - #[inline] - fn next_n(&mut self, buf: &mut [u8]) -> Result<(), ReadError> { - if let Some(data_size) = (self.end as usize).checked_sub(self.data as usize) { - if buf.len() > data_size { - return Err(ReadError::ExhaustedInput); +} + +word_wrapper!(U16le, u16); +word_wrapper!(U16be, u16); +word_wrapper!(U32le, u32); +word_wrapper!(U32be, u32); +word_wrapper!(U64le, u64); +word_wrapper!(U64be, u64); + +macro_rules! u8reader_reader_impl { + ($addr_size:ident, $word:ident, $word_from_slice:expr, $words_from_slice:expr) => { + impl Reader<$addr_size, $word> for U8Reader<'_> { + #[inline] + fn next(&mut self) -> Result<$word, ReadError> { + let data_size = self.end as usize - self.data as usize; + + if core::mem::size_of::<$word>() > data_size { + return Err(ReadError::ExhaustedInput); + } + + // `word_from_slice` knows that we have bounds-checked that `word`-many bytes are + // available. + let word = $word_from_slice(self.data); + unsafe { + self.data = self.data.offset(core::mem::size_of::<$word>() as isize); + } + Ok(word) } - unsafe { - core::ptr::copy_nonoverlapping(self.data, buf.as_mut_ptr(), buf.len()); + #[inline] + fn next_n(&mut self, buf: &mut [$word]) -> Result<(), ReadError> { + let data_size = self.end as usize - self.data as usize; + + let words_size_bytes = buf.len() * core::mem::size_of::<$word>(); + if words_size_bytes > data_size { + return Err(ReadError::ExhaustedInput); + } + + // `word_from_slice` knows that we have bounds-checked that `word`-many bytes are + // available. + $words_from_slice(self.data, buf); + unsafe { + self.data = self.data.offset(words_size_bytes as isize); + } + Ok(()) + } + #[inline] + fn mark(&mut self) { + self.mark = self.data; } - unsafe { - self.data = self.data.offset(buf.len() as isize); + #[inline] + fn offset(&mut self) -> $addr_size { + (self.data as usize - self.mark as usize) as $addr_size + } + #[inline] + fn total_offset(&mut self) -> $addr_size { + (self.data as usize - self.start as usize) as $addr_size } - Ok(()) - } else { - Err(ReadError::ExhaustedInput) } - } - #[inline] - fn mark(&mut self) { - self.mark = self.data; - } - #[inline] - fn offset(&mut self) -> u64 { - self.data as u64 - self.mark as u64 - } - #[inline] - fn total_offset(&mut self) -> u64 { - self.data as u64 - self.start as u64 + } } -impl Reader<u32, u8> for U8Reader<'_> { - fn next(&mut self) -> Result<u8, ReadError> { - if self.data == self.end { - Err(ReadError::ExhaustedInput) - } else { - let word = unsafe { core::ptr::read(self.data) }; - unsafe { - self.data = self.data.offset(1); - } - Ok(word) - } +macro_rules! u8reader_each_addr_size { + ($word:ident, $word_from_slice:expr, $words_from_slice:expr) => { + u8reader_reader_impl!(u64, $word, $word_from_slice, $words_from_slice); + u8reader_reader_impl!(u32, $word, $word_from_slice, $words_from_slice); } - #[inline] - fn next_n(&mut self, buf: &mut [u8]) -> Result<(), ReadError> { - if let Some(data_size) = (self.end as usize).checked_sub(self.data as usize) { - if buf.len() > data_size { - return Err(ReadError::ExhaustedInput); - } - unsafe { - core::ptr::copy_nonoverlapping(self.data, buf.as_mut_ptr(), buf.len()); - } - self.data = unsafe { self.data.offset(buf.len() as isize) }; - Ok(()) - } else { - Err(ReadError::ExhaustedInput) +} +u8reader_each_addr_size!(u8, + |ptr: *const u8| { unsafe { core::ptr::read(ptr) } }, + |ptr: *const u8, buf: &mut [u8]| { + unsafe { + core::ptr::copy_nonoverlapping(ptr, buf.as_mut_ptr(), buf.len()) } } - fn mark(&mut self) { - self.mark = self.data; - } - fn offset(&mut self) -> u32 { - self.data as u32 - self.mark as u32 - } - fn total_offset(&mut self) -> u32 { - self.data as u32 - self.start as u32 - } -} +); -/* -#[derive(Debug, PartialEq, Eq)] -pub struct U16le(pub u16); - -impl Reader<U16le> for &[u8] { - fn next(&mut self) -> Result<U16le, ReadError> { - if self.len() < 2 { - Err(ReadError::ExhaustedInput) - } else { - let bytes = [self[0], self[1]]; - *self = &self[2..]; - Ok(U16le(u16::from_le_bytes(bytes))) +u8reader_each_addr_size!(U16le, + |ptr: *const u8| { + let mut word = [0u8; 2]; + unsafe { + core::ptr::copy_nonoverlapping(ptr, word.as_mut_ptr(), word.len()); + } + U16le(u16::from_le_bytes(word)) + }, + |ptr: *const u8, buf: &mut [U16le]| { + // `U16le` are layout-identical to u16, so we can just copy into buf + unsafe { + core::ptr::copy_nonoverlapping(ptr, buf.as_mut_ptr() as *mut u8, buf.len() * core::mem::size_of::<U16le>()) } } -} +); -#[derive(Debug, PartialEq, Eq)] -pub struct U16be(pub u16); - -impl Reader<U16be> for &[u8] { - fn next(&mut self) -> Result<U16be, ReadError> { - if self.len() < 2 { - Err(ReadError::ExhaustedInput) - } else { - let bytes = [self[0], self[1]]; - *self = &self[2..]; - Ok(U16be(u16::from_be_bytes(bytes))) +u8reader_each_addr_size!(U32le, + |ptr: *const u8| { + let mut word = [0u8; 4]; + unsafe { + core::ptr::copy_nonoverlapping(ptr, word.as_mut_ptr(), word.len()); + } + U32le(u32::from_le_bytes(word)) + }, + |ptr: *const u8, buf: &mut [U32le]| { + // `U32le` are layout-identical to u32, so we can just copy into buf + unsafe { + core::ptr::copy_nonoverlapping(ptr, buf.as_mut_ptr() as *mut u8, buf.len() * core::mem::size_of::<U32le>()) } } -} - -#[derive(Debug, PartialEq, Eq)] -pub struct U32le(pub u32); +); -impl Reader<U32le> for &[u8] { - fn next(&mut self) -> Result<U32le, ReadError> { - if self.len() < 4 { - Err(ReadError::ExhaustedInput) - } else { - let bytes = [self[0], self[1], self[2], self[3]]; - *self = &self[4..]; - Ok(U32le(u32::from_le_bytes(bytes))) +u8reader_each_addr_size!(U64le, + |ptr: *const u8| { + let mut word = [0u8; 8]; + unsafe { + core::ptr::copy_nonoverlapping(ptr, word.as_mut_ptr(), word.len()); + } + U64le(u64::from_le_bytes(word)) + }, + |ptr: *const u8, buf: &mut [U64le]| { + // `U64le` are layout-identical to u64, so we can just copy into buf + unsafe { + core::ptr::copy_nonoverlapping(ptr, buf.as_mut_ptr() as *mut u8, buf.len() * core::mem::size_of::<U64le>()) } } -} +); -#[derive(Debug, PartialEq, Eq)] -pub struct U32be(pub u32); +u8reader_each_addr_size!(U16be, + |ptr: *const u8| { + let mut word = [0u8; 2]; + unsafe { + core::ptr::copy_nonoverlapping(ptr, word.as_mut_ptr(), word.len()); + } + U16be(u16::from_be_bytes(word)) + }, + |ptr: *const u8, buf: &mut [U16be]| { + // `U16be` are layout-identical to u16, so we can just copy into buf + unsafe { + core::ptr::copy_nonoverlapping(ptr, buf.as_mut_ptr() as *mut u8, buf.len() * core::mem::size_of::<U16be>()) + } -impl Reader<U32be> for &[u8] { - fn next(&mut self) -> Result<U32be, ReadError> { - if self.len() < 4 { - Err(ReadError::ExhaustedInput) - } else { - let bytes = [self[0], self[1], self[2], self[3]]; - *self = &self[4..]; - Ok(U32be(u32::from_be_bytes(bytes))) + // but now we have to bswap all the words + for i in 0..buf.len() { + buf[i] = U16be(buf[i].0.swap_bytes()); } } -} +); -#[derive(Debug, PartialEq, Eq)] -pub struct U64le(pub u64); +u8reader_each_addr_size!(U32be, + |ptr: *const u8| { + let mut word = [0u8; 4]; + unsafe { + core::ptr::copy_nonoverlapping(ptr, word.as_mut_ptr(), word.len()); + } + U32be(u32::from_be_bytes(word)) + }, + |ptr: *const u8, buf: &mut [U32be]| { + // `U32be` are layout-identical to u32, so we can just copy into buf + unsafe { + core::ptr::copy_nonoverlapping(ptr, buf.as_mut_ptr() as *mut u8, buf.len() * core::mem::size_of::<U32be>()) + } -impl Reader<U64le> for &[u8] { - fn next(&mut self) -> Result<U64le, ReadError> { - if self.len() < 8 { - Err(ReadError::ExhaustedInput) - } else { - let bytes = [self[0], self[1], self[2], self[3], self[4], self[5], self[6], self[7]]; - *self = &self[8..]; - Ok(U64le(u64::from_le_bytes(bytes))) + // but now we have to bswap all the words + for i in 0..buf.len() { + buf[i] = U32be(buf[i].0.swap_bytes()); } } -} +); -#[derive(Debug, PartialEq, Eq)] -pub struct U64be(pub u64); - -impl Reader<U64be> for &[u8] { - fn next(&mut self) -> Result<U64be, ReadError> { - if self.len() < 8 { - Err(ReadError::ExhaustedInput) - } else { - let bytes = [self[0], self[1], self[2], self[3], self[4], self[5], self[6], self[7]]; - *self = &self[8..]; - Ok(U64be(u64::from_be_bytes(bytes))) +u8reader_each_addr_size!(U64be, + |ptr: *const u8| { + let mut word = [0u8; 8]; + unsafe { + core::ptr::copy_nonoverlapping(ptr, word.as_mut_ptr(), word.len()); + } + U64be(u64::from_be_bytes(word)) + }, + |ptr: *const u8, buf: &mut [U64be]| { + // `U64be` are layout-identical to u64, so we can just copy into buf + unsafe { + core::ptr::copy_nonoverlapping(ptr, buf.as_mut_ptr() as *mut u8, buf.len() * core::mem::size_of::<U64be>()) } - } -} -impl core::fmt::Display for U16le { - fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result { - write!(f, "{}", self.0) - } -} -impl core::fmt::Display for U16be { - fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result { - write!(f, "{}", self.0) - } -} -impl core::fmt::Display for U32le { - fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result { - write!(f, "{}", self.0) - } -} -impl core::fmt::Display for U32be { - fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result { - write!(f, "{}", self.0) - } -} -impl core::fmt::Display for U64le { - fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result { - write!(f, "{}", self.0) - } -} -impl core::fmt::Display for U64be { - fn fmt(&self, f: &mut core::fmt::Formatter) -> core::fmt::Result { - write!(f, "{}", self.0) + // but now we have to bswap all the words + for i in 0..buf.len() { + buf[i] = U64be(buf[i].0.swap_bytes()); + } } -} -*/ +); |