Merge a patch from kpcyrd to remove some unsafe blocks.

A part of the patch involves copying or initializing arrays, but the
performance impact should be negligible.  TryFrom will eliminate copying
when stabilized.

src/endian.rs

@@ -46,44 +46,40 @@ pub struct LittleEndian;
 macro_rules! generate_load {
     ($name:ident, $int_type:ident, $from_func:ident) => (
         fn $name(buf: &[u8], offset: usize) -> $int_type {
-            // Check if the specified range of the slice is valid
-            // before transmute().  This will also detect the
-            // wrap-around of (offset + size_of) in the release mode.
-            let buf = &buf[offset .. offset + mem::size_of::<$int_type>()];
-            let ptr = buf.as_ptr() as *const $int_type;
-            let num = unsafe { mem::transmute(*ptr) };
+            let mut num = [0u8; mem::size_of::<$int_type>()];
+            num.copy_from_slice(
+                &buf[offset .. offset + mem::size_of::<$int_type>()]);
             $int_type::$from_func(num)
         }
     )
 }
 
 macro_rules! generate_write {
-    ($name:ident, $int_type:ident, $type_size:expr, $to_func:ident) => (
+    ($name:ident, $int_type:ident, $to_func:ident) => (
         fn $name<W>(w: &mut W, num: $int_type)
                     -> io::Result<()> where W: io::Write {
-            let buf: [u8; $type_size] =
-                unsafe { mem::transmute(num.$to_func()) };
+            let buf = num.$to_func();
             w.write_all(&buf)
         }
     )
 }
 
 impl Endian for BigEndian {
-    generate_load!(loadu16, u16, from_be);
-    generate_load!(loadu32, u32, from_be);
-    generate_load!(loadu64, u64, from_be);
-    generate_write!(writeu16, u16, 2, to_be);
-    generate_write!(writeu32, u32, 4, to_be);
-    generate_write!(writeu64, u64, 8, to_be);
+    generate_load!(loadu16, u16, from_be_bytes);
+    generate_load!(loadu32, u32, from_be_bytes);
+    generate_load!(loadu64, u64, from_be_bytes);
+    generate_write!(writeu16, u16, to_be_bytes);
+    generate_write!(writeu32, u32, to_be_bytes);
+    generate_write!(writeu64, u64, to_be_bytes);
 }
 
 impl Endian for LittleEndian {
-    generate_load!(loadu16, u16, from_le);
-    generate_load!(loadu32, u32, from_le);
-    generate_load!(loadu64, u64, from_le);
-    generate_write!(writeu16, u16, 2, to_le);
-    generate_write!(writeu32, u32, 4, to_le);
-    generate_write!(writeu64, u64, 8, to_le);
+    generate_load!(loadu16, u16, from_le_bytes);
+    generate_load!(loadu32, u32, from_le_bytes);
+    generate_load!(loadu64, u64, from_le_bytes);
+    generate_write!(writeu16, u16, to_le_bytes);
+    generate_write!(writeu32, u32, to_le_bytes);
+    generate_write!(writeu64, u64, to_le_bytes);
 }
 
 #[cfg(test)]

src/util.rs

@@ -34,12 +34,12 @@ const ASCII_A: u8 = 0x41;
 const ASCII_Z: u8 = 0x5a;
 
 pub fn read8<R>(reader: &mut R) -> Result<u8, io::Error> where R: io::Read {
-    let mut buf: [u8; 1] = unsafe { ::std::mem::uninitialized() };
+    let mut buf = [0u8; 1];
     reader.read_exact(&mut buf).and(Ok(buf[0]))
 }
 
 pub fn read16<R>(reader: &mut R) -> Result<u16, io::Error> where R: io::Read {
-    let mut buf: [u8; 2] = unsafe { ::std::mem::uninitialized() };
+    let mut buf = [0u8; 2];
     reader.read_exact(&mut buf)?;
     Ok(((buf[0] as u16) << 8) + buf[1] as u16)
 }

src/value.rs

@@ -357,10 +357,10 @@ fn parse_rational<'a, E>(data: &'a [u8], offset: usize, count: usize)
 
 fn parse_sbyte<'a>(data: &'a [u8], offset: usize, count: usize)
                    -> Value<'a> {
-    let uslice = &data[offset .. offset + count];
-    let islice = unsafe { ::std::slice::from_raw_parts(
-        uslice.as_ptr() as *const i8, count) };
-    Value::SByte(islice.to_vec())
+    let bytes = data[offset .. offset + count].into_iter()
+        .map(|x| *x as i8)
+        .collect();
+    Value::SByte(bytes)
 }
 
 fn parse_undefined<'a>(data: &'a [u8], offset: usize, count: usize)

src/writer.rs

@@ -26,7 +26,6 @@
 
 use std::io;
 use std::io::{Seek, SeekFrom, Write};
-use std::slice;
 
 use endian::{Endian, BigEndian, LittleEndian};
 use error::Error;
@@ -527,9 +526,10 @@ fn compose_value<E>(value: &Value)
             Ok((5, vec.len(), buf))
         },
         Value::SByte(ref vec) => {
-            let uslice = unsafe { slice::from_raw_parts(
-                vec.as_ptr() as *const u8, vec.len()) };
-            Ok((6, vec.len(), uslice.to_vec()))
+            let bytes = vec.into_iter()
+                .map(|x| *x as u8)
+                .collect();
+            Ok((6, vec.len(), bytes))
         },
         Value::Undefined(ref s, _) =>
             Ok((7, s.len(), s.to_vec())),