implement BufMut for Buffer

Cargo.toml

@@ -17,3 +17,4 @@ include = [
 ]
 
 [dependencies]
+bytes = "1.8.0"

src/lib.rs

@@ -47,14 +47,17 @@
 //!   assert_eq!(b.data(), &b"cd"[..]);
 //! }
 //!
-use std::{cmp, ptr};
-use std::io::{self,Write,Read};
+use std::io::{self, Read, Write};
 use std::iter::repeat;
+use std::{cmp, ptr};
+
+extern crate bytes;
+use bytes::BufMut;
 
 /// the Buffer contains the underlying memory and data positions
 ///
 /// In all cases, `0 ≤ position ≤ end ≤ capacity` should be true
-#[derive(Debug,PartialEq,Clone)]
+#[derive(Debug, PartialEq, Clone)]
 pub struct Buffer {
     /// the Vec containing the data
     memory: Vec<u8>,
@@ -64,7 +67,7 @@ pub struct Buffer {
     position: usize,
     /// the current end of the available data
     /// and beginning of the available space
-  end:      usize
+    end: usize,
 }
 
 impl Buffer {
@@ -76,7 +79,7 @@ impl Buffer {
             memory: v,
             capacity: capacity,
             position: 0,
-      end:      0
+            end: 0,
         }
     }
 
@@ -88,7 +91,7 @@ impl Buffer {
             memory: Vec::from(data),
             capacity: data.len(),
             position: 0,
-      end:      data.len()
+            end: data.len(),
         }
     }
 
@@ -204,7 +207,7 @@ impl Buffer {
 
     /// returns a mutable slice with all the available space to
     /// write to
-  pub fn space(&mut self) -> &mut[u8] {
+    pub fn space(&mut self) -> &mut [u8] {
         &mut self.memory[self.end..self.capacity]
     }
 
@@ -215,7 +218,11 @@ impl Buffer {
         if self.position > 0 {
             unsafe {
                 let length = self.end - self.position;
-        ptr::copy( (&self.memory[self.position..self.end]).as_ptr(), (&mut self.memory[..length]).as_mut_ptr(), length);
+                ptr::copy(
+                    (&self.memory[self.position..self.end]).as_ptr(),
+                    (&mut self.memory[..length]).as_mut_ptr(),
+                    length,
+                );
                 self.position = 0;
                 self.end = length;
             }
@@ -226,16 +233,16 @@ impl Buffer {
     #[doc(hidden)]
     pub fn delete_slice(&mut self, start: usize, length: usize) -> Option<usize> {
         if start + length >= self.available_data() {
-      return None
+            return None;
         }
 
         unsafe {
             let begin = self.position + start;
             let next_end = self.end - length;
             ptr::copy(
-        (&self.memory[begin+length..self.end]).as_ptr(),
+                (&self.memory[begin + length..self.end]).as_ptr(),
                 (&mut self.memory[begin..next_end]).as_mut_ptr(),
-        self.end - (begin+length)
+                self.end - (begin + length),
             );
             self.end = next_end;
         }
@@ -246,9 +253,10 @@ impl Buffer {
     #[doc(hidden)]
     pub fn replace_slice(&mut self, data: &[u8], start: usize, length: usize) -> Option<usize> {
         let data_len = data.len();
-    if start + length > self.available_data() ||
-      self.position + start + data_len > self.capacity {
-      return None
+        if start + length > self.available_data()
+            || self.position + start + data_len > self.capacity
+        {
+            return None;
         }
 
         unsafe {
@@ -256,15 +264,31 @@ impl Buffer {
             let slice_end = begin + data_len;
             // we reduced the data size
             if data_len < length {
-        ptr::copy(data.as_ptr(), (&mut self.memory[begin..slice_end]).as_mut_ptr(), data_len);
+                ptr::copy(
+                    data.as_ptr(),
+                    (&mut self.memory[begin..slice_end]).as_mut_ptr(),
+                    data_len,
+                );
 
-        ptr::copy((&self.memory[start+length..self.end]).as_ptr(), (&mut self.memory[slice_end..]).as_mut_ptr(), self.end - (start + length));
+                ptr::copy(
+                    (&self.memory[start + length..self.end]).as_ptr(),
+                    (&mut self.memory[slice_end..]).as_mut_ptr(),
+                    self.end - (start + length),
+                );
                 self.end = self.end - (length - data_len);
 
             // we put more data in the buffer
             } else {
-        ptr::copy((&self.memory[start+length..self.end]).as_ptr(), (&mut self.memory[start+data_len..]).as_mut_ptr(), self.end - (start + length));
-        ptr::copy(data.as_ptr(), (&mut self.memory[begin..slice_end]).as_mut_ptr(), data_len);
+                ptr::copy(
+                    (&self.memory[start + length..self.end]).as_ptr(),
+                    (&mut self.memory[start + data_len..]).as_mut_ptr(),
+                    self.end - (start + length),
+                );
+                ptr::copy(
+                    data.as_ptr(),
+                    (&mut self.memory[begin..slice_end]).as_mut_ptr(),
+                    data_len,
+                );
                 self.end = self.end + data_len - length;
             }
         }
@@ -275,16 +299,23 @@ impl Buffer {
     #[doc(hidden)]
     pub fn insert_slice(&mut self, data: &[u8], start: usize) -> Option<usize> {
         let data_len = data.len();
-    if start > self.available_data() ||
-      self.position + self.end + data_len > self.capacity {
-      return None
+        if start > self.available_data() || self.position + self.end + data_len > self.capacity {
+            return None;
         }
 
         unsafe {
             let begin = self.position + start;
             let slice_end = begin + data_len;
-      ptr::copy((&self.memory[start..self.end]).as_ptr(), (&mut self.memory[start+data_len..]).as_mut_ptr(), self.end - start);
-      ptr::copy(data.as_ptr(), (&mut self.memory[begin..slice_end]).as_mut_ptr(), data_len);
+            ptr::copy(
+                (&self.memory[start..self.end]).as_ptr(),
+                (&mut self.memory[start + data_len..]).as_mut_ptr(),
+                self.end - start,
+            );
+            ptr::copy(
+                data.as_ptr(),
+                (&mut self.memory[begin..slice_end]).as_mut_ptr(),
+                data_len,
+            );
             self.end = self.end + data_len;
         }
         Some(self.available_data())
@@ -294,8 +325,11 @@ impl Buffer {
 impl Write for Buffer {
     fn write(&mut self, buf: &[u8]) -> io::Result<usize> {
         match self.space().write(buf) {
-      Ok(size) => { self.fill(size); Ok(size) },
-      err      => err
+            Ok(size) => {
+                self.fill(size);
+                Ok(size)
+            }
+            err => err,
         }
     }
 
@@ -308,13 +342,31 @@ impl Read for Buffer {
     fn read(&mut self, buf: &mut [u8]) -> io::Result<usize> {
         let len = cmp::min(self.available_data(), buf.len());
         unsafe {
-      ptr::copy((&self.memory[self.position..self.position+len]).as_ptr(), buf.as_mut_ptr(), len);
+            ptr::copy(
+                (&self.memory[self.position..self.position + len]).as_ptr(),
+                buf.as_mut_ptr(),
+                len,
+            );
             self.position += len;
         }
         Ok(len)
     }
 }
 
+unsafe impl BufMut for Buffer {
+    fn remaining_mut(&self) -> usize {
+        self.available_space()
+    }
+
+    unsafe fn advance_mut(&mut self, cnt: usize) {
+        self.fill(cnt);
+    }
+
+    fn chunk_mut(&mut self) -> &mut bytes::buf::UninitSlice {
+        self.space().into()
+    }
+}
+
 #[cfg(test)]
 mod tests {
     use super::*;
@@ -397,7 +449,7 @@ mod tests {
     use std::str;
     #[test]
     fn set_position() {
-    let mut output = [0;5];
+        let mut output = [0; 5];
         let mut b = Buffer::with_capacity(10);
         let _ = b.write(&b"abcdefgh"[..]);
         let _ = b.read(&mut output);