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pub use core::{convert, fmt, option, result, str};
#[inline]
pub fn align(val: usize, to: usize) -> usize {
val + (to - (val % to)) % to
}
#[derive(Debug)]
pub enum SliceReadError {
UnexpectedEndOfInput,
}
pub type SliceReadResult<T> = Result<T, SliceReadError>;
pub trait SliceRead {
fn read_be_u32(&self, pos: usize) -> SliceReadResult<u32>;
fn read_be_u64(&self, pos: usize) -> SliceReadResult<u64>;
fn read_bstring0(&self, pos: usize) -> SliceReadResult<&[u8]>;
fn subslice(&self, start: usize, len: usize) -> SliceReadResult<&[u8]>;
}
impl<'a> SliceRead for &'a [u8] {
fn read_be_u32(&self, pos: usize) -> SliceReadResult<u32> {
if ! (pos+4 <= self.len()) {
return Err(SliceReadError::UnexpectedEndOfInput)
}
Ok(
(self[pos] as u32) << 24
| (self[pos+1] as u32) << 16
| (self[pos+2] as u32) << 8
| (self[pos+3] as u32)
)
}
fn read_be_u64(&self, pos: usize) -> SliceReadResult<u64> {
if ! (pos+8 <= self.len()) {
return Err(SliceReadError::UnexpectedEndOfInput)
}
Ok(
(self[pos] as u64) << 56
| (self[pos+1] as u64) << 48
| (self[pos+2] as u64) << 40
| (self[pos+3] as u64) << 32
| (self[pos+4] as u64) << 24
| (self[pos+5] as u64) << 16
| (self[pos+6] as u64) << 8
| (self[pos+7] as u64)
)
}
fn read_bstring0(&self, pos: usize) -> SliceReadResult<&[u8]> {
let mut cur = pos;
while cur < self.len() {
if self[cur] == 0 {
return Ok(&self[pos..cur])
}
cur += 1;
}
Err(SliceReadError::UnexpectedEndOfInput)
}
fn subslice(&self, start: usize, end: usize) -> SliceReadResult<&[u8]> {
if ! (end < self.len()) {
return Err(SliceReadError::UnexpectedEndOfInput)
}
Ok(&self[start..end])
}
}