You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: util.rs
    path of file: ./repos/divans/src/bin
    
    the code of the file until where you have to start completion: // Copyright 2017 Dropbox, Inc
//
//   Licensed under the Apache License, Version 2.0 (the "License");
//   you may not use this file except in compliance with the License.
//   You may obtain a copy of the License at
//
//       http://www.apache.org/licenses/LICENSE-2.0
//
//   Unless required by applicable law or agreed to in writing, software
//   distributed under the License is distributed on an "AS IS" BASIS,
//   WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
//   See the License for the specific language governing permissions and
//   limitations under the License.

use core;
use std::io;
use super::{SliceWrapperMut,SliceWrapper};
use super::alloc;
pub struct DynBuffer(Box<[u8]>);

impl core::default::Default for DynBuffer {
  fn default() -> Self {
    let v: Vec<u8> = Vec::new();
    let b = v.into_boxed_slice();
    DynBuffer(b)
  }
}


impl DynBuffer {
    #[allow(unused)]
    pub fn new(size:usize) -> DynBuffer {
        DynBuffer(vec![0u8;size].into_boxed_slice())
    }
}

impl SliceWrapper<u8> for DynBuffer {
  fn slice(&self) -> &[u8] {
    &*self.0
  }
}

impl SliceWrapperMut<u8> for DynBuffer {
  fn slice_mut(&mut self) -> &mut [u8] {
    &mut *self.0
  }
}

#[cfg(feature="inplace-new")]
macro_rules! define_static_heap_buffer {
    ($name : ident, $size: expr) => {
        pub struct $name(Box<[u8;$size]>);
        impl core::default::Default for $name {
            fn default() -> Self {
                static DEFAULT_VALUE: [u8;$size] = [0u8;$size];
                $name(Box::<[u8;$size]>::new(DEFAULT_VALUE))
            }
        }
        impl SliceWrapper<u8> for $name {
            fn slice(&self) -> &[u8] {
                &*self.0
            }
        }

        impl SliceWrapperMut<u8> for $name {
            fn slice_mut(&mut self) -> &mut [u8] {
                &mut *self.0
            }
        }
    }
}

#[cfg(not(feature="inplace-new"))]
macro_rules! define_static_heap_buffer {
    ($name : ident, $size: expr) => {
        pub struct $name(DynBuffer);
        impl core::default::Default for $name {
            fn default() -> Self {
                $name(DynBuffer((vec![0u8;$size]).into_boxed_slice()))
            }
        }
        impl SliceWrapper<u8> for $name {
            fn slice(&self) -> &[u8] {
                (&*(self.0).0).split_at($size).0
            }
       
    
fn quoted_slice_to_vec(s: &[u8]) -> Result<Vec<u8>, io::Error> {
    if s.len() < 2 {
        return Err(io::Error::new(io::ErrorKind::InvalidInput, core::str::from_utf8(s).unwrap()));
    }
    let mut output = Vec::<u8>::with_capacity(s.len() - 2);
    let mut must_end = false;
    let mut escaped = false;
    let mut hexed = false;
    let mut upper: Option<u8> = None;
    
    for byte_ref in s.iter().skip(1) {
        let byte = *byte_ref;
        if must_end {
            return Err(io::Error::new(io::ErrorKind::InvalidInput, core::str::from_utf8(s).unwrap())); 
        }
        if byte ==  b'\"' && !escaped {
            must_end = true;
            continue;
        }
        
        if byte == b'\\' && !escaped {
            escaped = true;
            continue;
        }
        if escaped {
            if hexed {
                if let Ok(nib) = hex_to_nibble(byte) {
                    if let Some(unib) = upper {
                        output.push((unib << 4) | nib);
                        hexed = false;
                        escaped = false;
                        upper = None;
                    } else {
                        upper = Some(nib);
                    }
                } else {
                    return Err(io::Error::new(io::ErrorKind::InvalidInput, core::str::from_utf8(s).unwrap())); 
                }
            } else if byte == b'x' {
                hexed = true;
            } else if byte == b'n' {
                output.push(b'\n');
                escaped = false;
            } else if byte == b'r' {
                output.push(b'\r');
                escaped = false;
            } else if byte == b't' {
                output.push(b'\t');
                escaped = false;
            } else if byte == b'\\' {
                output.push(b'\\');
                escaped = false;
            } else if byte == b'\'' {
                output.push(b'\'');
                escaped = false;
            } else if byte == b'\"' {
                output.push(b'\"');
                escaped = false;
            } else if byte == b'?' {
                output.push(b'?');
                escaped = false;
            } else {
                return Err(io::Error::new(io::ErrorKind::InvalidInput, core::str::from_utf8(s).unwrap()));
            }
        } else {
            output.push(byte);
        }
    }
    if hexed || escaped || !must_end {
        return Err(io::Error::new(io::ErrorKind::InvalidInput, core::str::from_utf8(s).unwrap()));
    }
    return Ok(output);
}