Remove byteorder dependency (#280)

Author: Douman

Cargo.toml

@@ -20,7 +20,6 @@ edition = "2018"
 publish = false
 
 [dependencies]
-byteorder = "1.3"
 serde = { version = "1.0", optional = true }
 either = { version = "1.5", default-features = false, optional = true }
 

src/buf/buf.rs

@@ -1,38 +1,44 @@
 use super::{IntoBuf, Take, Reader, FromBuf, Chain};
-use byteorder::{BigEndian, ByteOrder, LittleEndian};
 
-use std::{cmp, io::IoSlice, ptr};
+use std::{cmp, io::IoSlice, ptr, mem};
 
 macro_rules! buf_get_impl {
-    ($this:ident, $size:expr, $conv:path) => ({
+    ($this:ident, $typ:tt::$conv:tt) => ({
+        const SIZE: usize = mem::size_of::<$typ>();
          // try to convert directly from the bytes
-        let ret = {
-            // this Option<ret> trick is to avoid keeping a borrow on self
-            // when advance() is called (mut borrow) and to call bytes() only once
-            if let Some(src) = $this.bytes().get(..($size)) {
-                Some($conv(src))
-            } else {
-                None
-            }
-        };
+         // this Option<ret> trick is to avoid keeping a borrow on self
+         // when advance() is called (mut borrow) and to call bytes() only once
+        let ret =  $this.bytes().get(..SIZE).map(|src| unsafe {
+            $typ::$conv(*(src as *const _ as *const [_; SIZE]))
+        });
+
         if let Some(ret) = ret {
              // if the direct conversion was possible, advance and return
-            $this.advance($size);
+            $this.advance(SIZE);
             return ret;
         } else {
             // if not we copy the bytes in a temp buffer then convert
-            let mut buf = [0; ($size)];
+            let mut buf = [0; SIZE];
             $this.copy_to_slice(&mut buf); // (do the advance)
-            return $conv(&buf);
+            return $typ::$conv(buf);
         }
     });
-    ($this:ident, $buf_size:expr, $conv:path, $len_to_read:expr) => ({
+    (le => $this:ident, $typ:tt, $len_to_read:expr) => ({
+        debug_assert!(mem::size_of::<$typ>() >= $len_to_read);
+
         // The same trick as above does not improve the best case speed.
         // It seems to be linked to the way the method is optimised by the compiler
-        let mut buf = [0; ($buf_size)];
+        let mut buf = [0; (mem::size_of::<$typ>())];
         $this.copy_to_slice(&mut buf[..($len_to_read)]);
-        return $conv(&buf[..($len_to_read)], $len_to_read);
+        return $typ::from_le_bytes(buf);
     });
+    (be => $this:ident, $typ:tt, $len_to_read:expr) => {{
+        debug_assert!(mem::size_of::<$typ>() >= $len_to_read);
+
+        let mut buf = [0; (mem::size_of::<$typ>())];
+        $this.copy_to_slice(&mut buf[mem::size_of::<$typ>()-($len_to_read)..]);
+        return $typ::from_be_bytes(buf);
+    }};
 }
 
 /// Read bytes from a buffer.
@@ -314,7 +320,7 @@ pub trait Buf {
     ///
     /// This function panics if there is not enough remaining data in `self`.
     fn get_u16(&mut self) -> u16 {
-        buf_get_impl!(self, 2, BigEndian::read_u16);
+        buf_get_impl!(self, u16::from_be_bytes);
     }
 
     /// Gets an unsigned 16 bit integer from `self` in little-endian byte order.
@@ -334,7 +340,7 @@ pub trait Buf {
     ///
     /// This function panics if there is not enough remaining data in `self`.
     fn get_u16_le(&mut self) -> u16 {
-        buf_get_impl!(self, 2, LittleEndian::read_u16);
+        buf_get_impl!(self, u16::from_le_bytes);
     }
 
     /// Gets a signed 16 bit integer from `self` in big-endian byte order.
@@ -354,7 +360,7 @@ pub trait Buf {
     ///
     /// This function panics if there is not enough remaining data in `self`.
     fn get_i16(&mut self) -> i16 {
-        buf_get_impl!(self, 2, BigEndian::read_i16);
+        buf_get_impl!(self, i16::from_be_bytes);
     }
 
     /// Gets a signed 16 bit integer from `self` in little-endian byte order.
@@ -374,7 +380,7 @@ pub trait Buf {
     ///
     /// This function panics if there is not enough remaining data in `self`.
     fn get_i16_le(&mut self) -> i16 {
-        buf_get_impl!(self, 2, LittleEndian::read_i16);
+        buf_get_impl!(self, i16::from_le_bytes);
     }
 
     /// Gets an unsigned 32 bit integer from `self` in the big-endian byte order.
@@ -394,7 +400,7 @@ pub trait Buf {
     ///
     /// This function panics if there is not enough remaining data in `self`.
     fn get_u32(&mut self) -> u32 {
-        buf_get_impl!(self, 4, BigEndian::read_u32);
+        buf_get_impl!(self, u32::from_be_bytes);
     }
 
     /// Gets an unsigned 32 bit integer from `self` in the little-endian byte order.
@@ -414,7 +420,7 @@ pub trait Buf {
     ///
     /// This function panics if there is not enough remaining data in `self`.
     fn get_u32_le(&mut self) -> u32 {
-        buf_get_impl!(self, 4, LittleEndian::read_u32);
+        buf_get_impl!(self, u32::from_le_bytes);
     }
 
     /// Gets a signed 32 bit integer from `self` in big-endian byte order.
@@ -434,7 +440,7 @@ pub trait Buf {
     ///
     /// This function panics if there is not enough remaining data in `self`.
     fn get_i32(&mut self) -> i32 {
-        buf_get_impl!(self, 4, BigEndian::read_i32);
+        buf_get_impl!(self, i32::from_be_bytes);
     }
 
     /// Gets a signed 32 bit integer from `self` in little-endian byte order.
@@ -454,7 +460,7 @@ pub trait Buf {
     ///
     /// This function panics if there is not enough remaining data in `self`.
     fn get_i32_le(&mut self) -> i32 {
-        buf_get_impl!(self, 4, LittleEndian::read_i32);
+        buf_get_impl!(self, i32::from_le_bytes);
     }
 
     /// Gets an unsigned 64 bit integer from `self` in big-endian byte order.
@@ -474,7 +480,7 @@ pub trait Buf {
     ///
     /// This function panics if there is not enough remaining data in `self`.
     fn get_u64(&mut self) -> u64 {
-        buf_get_impl!(self, 8, BigEndian::read_u64);
+        buf_get_impl!(self, u64::from_be_bytes);
     }
 
     /// Gets an unsigned 64 bit integer from `self` in little-endian byte order.
@@ -494,7 +500,7 @@ pub trait Buf {
     ///
     /// This function panics if there is not enough remaining data in `self`.
     fn get_u64_le(&mut self) -> u64 {
-        buf_get_impl!(self, 8, LittleEndian::read_u64);
+        buf_get_impl!(self, u64::from_le_bytes);
     }
 
     /// Gets a signed 64 bit integer from `self` in big-endian byte order.
@@ -514,7 +520,7 @@ pub trait Buf {
     ///
     /// This function panics if there is not enough remaining data in `self`.
     fn get_i64(&mut self) -> i64 {
-        buf_get_impl!(self, 8, BigEndian::read_i64);
+        buf_get_impl!(self, i64::from_be_bytes);
     }
 
     /// Gets a signed 64 bit integer from `self` in little-endian byte order.
@@ -534,7 +540,7 @@ pub trait Buf {
     ///
     /// This function panics if there is not enough remaining data in `self`.
     fn get_i64_le(&mut self) -> i64 {
-        buf_get_impl!(self, 8, LittleEndian::read_i64);
+        buf_get_impl!(self, i64::from_le_bytes);
     }
 
     /// Gets an unsigned 128 bit integer from `self` in big-endian byte order.
@@ -554,7 +560,7 @@ pub trait Buf {
     ///
     /// This function panics if there is not enough remaining data in `self`.
     fn get_u128(&mut self) -> u128 {
-        buf_get_impl!(self, 16, BigEndian::read_u128);
+        buf_get_impl!(self, u128::from_be_bytes);
     }
 
     /// Gets an unsigned 128 bit integer from `self` in little-endian byte order.
@@ -574,7 +580,7 @@ pub trait Buf {
     ///
     /// This function panics if there is not enough remaining data in `self`.
     fn get_u128_le(&mut self) -> u128 {
-        buf_get_impl!(self, 16, LittleEndian::read_u128);
+        buf_get_impl!(self, u128::from_le_bytes);
     }
 
     /// Gets a signed 128 bit integer from `self` in big-endian byte order.
@@ -594,7 +600,7 @@ pub trait Buf {
     ///
     /// This function panics if there is not enough remaining data in `self`.
     fn get_i128(&mut self) -> i128 {
-        buf_get_impl!(self, 16, BigEndian::read_i128);
+        buf_get_impl!(self, i128::from_be_bytes);
     }
 
     /// Gets a signed 128 bit integer from `self` in little-endian byte order.
@@ -614,7 +620,7 @@ pub trait Buf {
     ///
     /// This function panics if there is not enough remaining data in `self`.
     fn get_i128_le(&mut self) -> i128 {
-        buf_get_impl!(self, 16, LittleEndian::read_i128);
+        buf_get_impl!(self, i128::from_le_bytes);
     }
 
     /// Gets an unsigned n-byte integer from `self` in big-endian byte order.
@@ -634,7 +640,7 @@ pub trait Buf {
     ///
     /// This function panics if there is not enough remaining data in `self`.
     fn get_uint(&mut self, nbytes: usize) -> u64 {
-        buf_get_impl!(self, 8, BigEndian::read_uint, nbytes);
+        buf_get_impl!(be => self, u64, nbytes);
     }
 
     /// Gets an unsigned n-byte integer from `self` in little-endian byte order.
@@ -654,7 +660,7 @@ pub trait Buf {
     ///
     /// This function panics if there is not enough remaining data in `self`.
     fn get_uint_le(&mut self, nbytes: usize) -> u64 {
-        buf_get_impl!(self, 8, LittleEndian::read_uint, nbytes);
+        buf_get_impl!(le => self, u64, nbytes);
     }
 
     /// Gets a signed n-byte integer from `self` in big-endian byte order.
@@ -674,7 +680,7 @@ pub trait Buf {
     ///
     /// This function panics if there is not enough remaining data in `self`.
     fn get_int(&mut self, nbytes: usize) -> i64 {
-        buf_get_impl!(self, 8, BigEndian::read_int, nbytes);
+        buf_get_impl!(be => self, i64, nbytes);
     }
 
     /// Gets a signed n-byte integer from `self` in little-endian byte order.
@@ -694,7 +700,7 @@ pub trait Buf {
     ///
     /// This function panics if there is not enough remaining data in `self`.
     fn get_int_le(&mut self, nbytes: usize) -> i64 {
-        buf_get_impl!(self, 8, LittleEndian::read_int, nbytes);
+        buf_get_impl!(le => self, i64, nbytes);
     }
 
     /// Gets an IEEE754 single-precision (4 bytes) floating point number from
@@ -715,7 +721,7 @@ pub trait Buf {
     ///
     /// This function panics if there is not enough remaining data in `self`.
     fn get_f32(&mut self) -> f32 {
-        buf_get_impl!(self, 4, BigEndian::read_f32);
+        f32::from_bits(Self::get_u32(self))
     }
 
     /// Gets an IEEE754 single-precision (4 bytes) floating point number from
@@ -736,7 +742,7 @@ pub trait Buf {
     ///
     /// This function panics if there is not enough remaining data in `self`.
     fn get_f32_le(&mut self) -> f32 {
-        buf_get_impl!(self, 4, LittleEndian::read_f32);
+        f32::from_bits(Self::get_u32_le(self))
     }
 
     /// Gets an IEEE754 double-precision (8 bytes) floating point number from
@@ -757,7 +763,7 @@ pub trait Buf {
     ///
     /// This function panics if there is not enough remaining data in `self`.
     fn get_f64(&mut self) -> f64 {
-        buf_get_impl!(self, 8, BigEndian::read_f64);
+        f64::from_bits(Self::get_u64(self))
     }
 
     /// Gets an IEEE754 double-precision (8 bytes) floating point number from
@@ -778,7 +784,7 @@ pub trait Buf {
     ///
     /// This function panics if there is not enough remaining data in `self`.
     fn get_f64_le(&mut self) -> f64 {
-        buf_get_impl!(self, 8, LittleEndian::read_f64);
+        f64::from_bits(Self::get_u64_le(self))
     }
 
     /// Transforms a `Buf` into a concrete buffer.