postcss 0.0.2

🚀 Fast and 100% API compatible postcss replacer
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use std::mem;
const BUFFER_SIZE: usize = u8::MAX as usize + 1;

#[derive(Debug)]
pub struct RefRing<'a> {
  buffer: [Option<&'a str>; BUFFER_SIZE],
  index: u8,
}

impl<'a> Default for RefRing<'a> {
  fn default() -> Self {
    RefRing {
      // SAFETY: SINCE NONE IS ZERO IN MEMORY REPRESENTATION,
      // WE COULD JUST ZEROED OUT THE WHOLE BUFFER TO INITIALIZE IT.
      buffer: unsafe { mem::zeroed() },
      index: 0,
    }
  }
}

impl<'a> RefRing<'a> {
  #[inline]
  pub fn push(&mut self, e: &'a str) {
    let index = self.index as usize;
    // The assert let the compiler optimize out the bounds checks.
    assert!(index < BUFFER_SIZE);
    self.buffer[index].replace(e);
    self.index = self.index.wrapping_add(1);
  }

  pub fn pop(&mut self) -> Option<&'a str> {
    self.index = self.index.wrapping_sub(1);
    let index = self.index as usize;
    // The assert let the compiler optimize out the bounds checks.
    assert!(index < BUFFER_SIZE);

    self.buffer[index].take()
  }
}