Merge pull request #103 from Manishearth/read-soundness

Remove read(), add read_u32() and read_u64() and use everywhere.

lexical-parse-float/src/slow.rs

@@ -335,7 +335,7 @@ macro_rules! round_up_nonzero {
 
         // First try reading 8-digits at a time.
         if iter.is_contiguous() {
-            while let Some(value) = iter.read::<u64>() {
+            while let Some(value) = iter.read_u64() {
                 // SAFETY: safe since we have at least 8 bytes in the buffer.
                 unsafe { iter.step_by_unchecked(8) };
                 if value != 0x3030_3030_3030_3030 {

lexical-parse-integer/src/algorithm.rs

@@ -217,7 +217,7 @@ where
     debug_assert!(Iter::IS_CONTIGUOUS);
 
     // Read our digits, validate the input, and check from there.
-    let bytes = u32::from_le(iter.read::<u32>()?);
+    let bytes = u32::from_le(iter.read_u32()?);
     if is_4digits::<FORMAT>(bytes) {
         // SAFETY: safe since we have at least 4 bytes in the buffer.
         unsafe { iter.step_by_unchecked(4) };
@@ -289,7 +289,7 @@ where
     debug_assert!(Iter::IS_CONTIGUOUS);
 
     // Read our digits, validate the input, and check from there.
-    let bytes = u64::from_le(iter.read::<u64>()?);
+    let bytes = u64::from_le(iter.read_u64()?);
     if is_8digits::<FORMAT>(bytes) {
         // SAFETY: safe since we have at least 8 bytes in the buffer.
         unsafe { iter.step_by_unchecked(8) };

lexical-util/src/iterator.rs

@@ -120,9 +120,14 @@ pub trait BytesIter<'a>: Iterator<Item = &'a u8> {
     /// many bytes as the size of V.
     unsafe fn read_unchecked<V>(&self) -> V;
 
-    /// Try to read a value of a different type from the iterator.
+    /// Try to read a the next four bytes as a u32.
     /// This advances the internal state of the iterator.
-    fn read<V>(&self) -> Option<V>;
+    fn read_u32(&self) -> Option<u32>;
+
+
+    /// Try to read the next eight bytes as a u64
+    /// This advances the internal state of the iterator.
+    fn read_u64(&self) -> Option<u64>;
 
     /// Advance the internal slice by `N` elements.
     ///

lexical-util/src/noskip.rs

@@ -105,7 +105,7 @@ impl<'a, const __: u128> Bytes<'a, __> {
     /// # Safety
     ///
     /// Safe as long as the number of the buffer is contains as least as
-    /// many bytes as the size of V.
+    /// many bytes as the size of V, and V is valid for all bit patterns.
     #[inline]
     #[allow(clippy::assertions_on_constants)]
     pub unsafe fn read_unchecked<V>(&self) -> V {
@@ -117,13 +117,26 @@ impl<'a, const __: u128> Bytes<'a, __> {
         unsafe { ptr::read_unaligned::<V>(slc.as_ptr() as *const _) }
     }
 
-    /// Try to read a value of a different type from the iterator.
+    /// Try to read a the next four bytes as a u32.
     /// This advances the internal state of the iterator.
     #[inline]
-    pub fn read<V>(&self) -> Option<V> {
-        if Self::IS_CONTIGUOUS && self.as_slice().len() >= mem::size_of::<V>() {
+    pub fn read_u32(&self) -> Option<u32> {
+        if Self::IS_CONTIGUOUS && self.as_slice().len() >= mem::size_of::<u32>() {
             // SAFETY: safe since we've guaranteed the buffer is greater than
-            // the number of elements read.
+            // the number of elements read. u32 is valid for all bit patterns
+            unsafe { Some(self.read_unchecked()) }
+        } else {
+            None
+        }
+    }
+
+    /// Try to read the next eight bytes as a u64
+    /// This advances the internal state of the iterator.
+    #[inline]
+    pub fn read_u64(&self) -> Option<u64> {
+        if Self::IS_CONTIGUOUS && self.as_slice().len() >= mem::size_of::<u64>() {
+            // SAFETY: safe since we've guaranteed the buffer is greater than
+            // the number of elements read. u64 is valid for all bit patterns
             unsafe { Some(self.read_unchecked()) }
         } else {
             None
@@ -288,8 +301,13 @@ impl<'a: 'b, 'b, const __: u128> BytesIter<'a> for BytesIterator<'a, 'b, __> {
     }
 
     #[inline]
-    fn read<V>(&self) -> Option<V> {
-        self.byte.read()
+    fn read_u32(&self) -> Option<u32> {
+        self.byte.read_u32()
+    }
+
+    #[inline]
+    fn read_u64(&self) -> Option<u64> {
+        self.byte.read_u64()
     }
 
     #[inline]

lexical-util/src/skip.rs

@@ -428,7 +428,7 @@ impl<'a, const FORMAT: u128> Bytes<'a, FORMAT> {
     /// # Safety
     ///
     /// Safe as long as the number of the buffer is contains as least as
-    /// many bytes as the size of V.
+    /// many bytes as the size of V, and V is valid for all bit patterns.
     #[inline]
     pub unsafe fn read_unchecked<V>(&self) -> V {
         debug_assert!(Self::IS_CONTIGUOUS);
@@ -439,19 +439,30 @@ impl<'a, const FORMAT: u128> Bytes<'a, FORMAT> {
         unsafe { ptr::read_unaligned::<V>(slc.as_ptr() as *const _) }
     }
 
-    /// Try to read a value of a different type from the iterator.
+    /// Try to read a the next four bytes as a u32.
     /// This advances the internal state of the iterator.
     #[inline]
-    pub fn read<V>(&self) -> Option<V> {
-        if Self::IS_CONTIGUOUS && self.as_slice().len() >= mem::size_of::<V>() {
+    unsafe fn read_u32(&self) -> Option<u32> {
+        if Self::IS_CONTIGUOUS && self.as_slice().len() >= mem::size_of::<u32>() {
             // SAFETY: safe since we've guaranteed the buffer is greater than
-            // the number of elements read.
+            // the number of elements read. u32 is valid for all bit patterns
+            unsafe { Some(self.read_unchecked()) }
+        } else {
+            None
+        }
+    }
+    /// Try to read a the next four bytes as a u32.
+    /// This advances the internal state of the iterator.
+    #[inline]
+    unsafe fn read_u64(&self) -> Option<u64> {
+        if Self::IS_CONTIGUOUS && self.as_slice().len() >= mem::size_of::<u64>() {
+            // SAFETY: safe since we've guaranteed the buffer is greater than
+            // the number of elements read. u64 is valid for all bit patterns
             unsafe { Some(self.read_unchecked()) }
         } else {
             None
         }
     }
-
     /// Check if the next element is a given value.
     #[inline]
     pub fn first_is(&mut self, value: u8) -> bool {