pcap_parser/

utils.rs

use std::ops;
use std::ops::{Deref, DerefMut};

/// A container for owned or borrowed data
pub enum Data<'a> {
    Owned(Vec<u8>),
    Borrowed(&'a [u8]),
}

/// A container for owned or borrowed mutable data
pub enum MutableData<'a> {
    Owned(Vec<u8>),
    Borrowed(&'a mut [u8]),
}

impl<'a> Data<'a> {
    #[inline]
    pub fn as_slice(&self) -> &[u8] {
        match self {
            Data::Owned(ref o) => o.deref(),
            Data::Borrowed(b) => b,
        }
    }
    #[inline]
    pub fn len(&self) -> usize {
        match self {
            Data::Owned(ref o) => o.len(),
            Data::Borrowed(b) => b.len(),
        }
    }
    #[inline]
    pub fn is_empty(&self) -> bool {
        match self {
            Data::Owned(ref o) => o.is_empty(),
            Data::Borrowed(b) => b.is_empty(),
        }
    }
}

impl<'a> MutableData<'a> {
    #[inline]
    pub fn as_slice(&self) -> &[u8] {
        match self {
            MutableData::Owned(ref o) => o.deref(),
            MutableData::Borrowed(ref b) => b,
        }
    }
    #[inline]
    pub fn as_mut_slice(&mut self) -> &mut [u8] {
        match self {
            MutableData::Owned(ref mut o) => o.deref_mut(),
            MutableData::Borrowed(ref mut b) => b,
        }
    }
    #[inline]
    pub fn len(&self) -> usize {
        match self {
            MutableData::Owned(ref o) => o.len(),
            MutableData::Borrowed(ref b) => b.len(),
        }
    }
    #[inline]
    pub fn is_empty(&self) -> bool {
        match self {
            MutableData::Owned(ref o) => o.is_empty(),
            MutableData::Borrowed(ref b) => b.is_empty(),
        }
    }
    /// Get an immutable version of the data
    pub fn into_immutable(self) -> Data<'a> {
        match self {
            MutableData::Owned(data) => Data::Owned(data),
            MutableData::Borrowed(data) => Data::Borrowed(data),
        }
    }
}

/* AsRef */

impl<'a> AsRef<[u8]> for Data<'a> {
    #[inline]
    fn as_ref(&self) -> &[u8] {
        self.as_slice()
    }
}

impl<'a> AsRef<[u8]> for MutableData<'a> {
    #[inline]
    fn as_ref(&self) -> &[u8] {
        self.as_slice()
    }
}

impl<'a> AsMut<[u8]> for MutableData<'a> {
    #[inline]
    fn as_mut(&mut self) -> &mut [u8] {
        self.as_mut_slice()
    }
}

/* Index */

macro_rules! impl_index {
    ($t:ident, $index_t:ty, $output_t:ty) => {
        impl<'p> ops::Index<$index_t> for $t<'p> {
            type Output = $output_t;
            #[inline]
            fn index(&self, index: $index_t) -> &$output_t {
                &self.as_slice().index(index)
            }
        }
    };
}

macro_rules! impl_index_mut {
    ($t:ident, $index_t:ty, $output_t:ty) => {
        impl<'p> ops::IndexMut<$index_t> for $t<'p> {
            #[inline]
            fn index_mut(&mut self, index: $index_t) -> &mut $output_t {
                self.as_mut_slice().index_mut(index)
            }
        }
    };
}

impl_index!(Data, usize, u8);
impl_index!(Data, ops::Range<usize>, [u8]);
impl_index!(Data, ops::RangeTo<usize>, [u8]);
impl_index!(Data, ops::RangeFrom<usize>, [u8]);
impl_index!(Data, ops::RangeFull, [u8]);
impl_index!(Data, ops::RangeInclusive<usize>, [u8]);
impl_index!(Data, ops::RangeToInclusive<usize>, [u8]);

impl_index!(MutableData, usize, u8);
impl_index!(MutableData, ops::Range<usize>, [u8]);
impl_index!(MutableData, ops::RangeTo<usize>, [u8]);
impl_index!(MutableData, ops::RangeFrom<usize>, [u8]);
impl_index!(MutableData, ops::RangeFull, [u8]);
impl_index!(MutableData, ops::RangeInclusive<usize>, [u8]);
impl_index!(MutableData, ops::RangeToInclusive<usize>, [u8]);

impl_index_mut!(MutableData, usize, u8);
impl_index_mut!(MutableData, ops::Range<usize>, [u8]);
impl_index_mut!(MutableData, ops::RangeTo<usize>, [u8]);
impl_index_mut!(MutableData, ops::RangeFrom<usize>, [u8]);
impl_index_mut!(MutableData, ops::RangeFull, [u8]);
impl_index_mut!(MutableData, ops::RangeInclusive<usize>, [u8]);
impl_index_mut!(MutableData, ops::RangeToInclusive<usize>, [u8]);

/* ******************* */

#[doc(hidden)]
#[macro_export]
macro_rules! read_u32_e {
    ($data:expr, $endian:expr) => {
        if $endian {
            let data = $data;
            (data[0] as u32) << 24
                | (data[1] as u32) << 16
                | (data[2] as u32) << 8
                | (data[3] as u32)
        } else {
            let data = $data;
            (data[3] as u32) << 24
                | (data[2] as u32) << 16
                | (data[1] as u32) << 8
                | (data[0] as u32)
        }
    };
}

#[doc(hidden)]
#[macro_export]
macro_rules! write_u32_e {
    ($data:expr, $val:expr, $endian:expr) => {
        let data = $data;
        let v = $val;
        let v1: u8 = ((v >> 24) & 0xff) as u8;
        let v2: u8 = ((v >> 16) & 0xff) as u8;
        let v3: u8 = ((v >> 8) & 0xff) as u8;
        let v4: u8 = ((v) & 0xff) as u8;
        if $endian {
            data[0] = v1;
            data[1] = v2;
            data[2] = v3;
            data[3] = v4;
        } else {
            data[0] = v4;
            data[1] = v3;
            data[2] = v2;
            data[3] = v1;
        }
    };
}

/// Generate an array reference to a subset
/// of a sliceable bit of data (which could be an array, or a slice,
/// or a Vec).
///
/// **Panics** if the slice is out of bounds.
///
/// implementation inspired from arrayref::array_ref
#[allow(unsafe_code)]
#[inline]
pub(crate) fn array_ref4(s: &[u8], offset: usize) -> &[u8; 4] {
    #[inline]
    unsafe fn as_array<T>(slice: &[T]) -> &[T; 4] {
        &*(slice.as_ptr() as *const [_; 4])
    }
    let slice = &s[offset..offset + 4];
    #[allow(unused_unsafe)]
    unsafe {
        as_array(slice)
    }
}