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use crate::buffer::Buffer;
use crate::error::Result;
use crate::util::bit_util;
use std::mem;
use std::ops::{BitAnd, BitOr};
#[derive(Debug, Clone)]
pub struct Bitmap {
pub(crate) bits: Buffer,
}
impl Bitmap {
pub fn new(num_bits: usize) -> Self {
let num_bytes = bit_util::ceil(num_bits, 8);
let len = bit_util::round_upto_multiple_of_64(num_bytes);
Bitmap {
bits: Buffer::from(&vec![0xFF; len]),
}
}
pub fn bit_len(&self) -> usize {
self.bits.len() * 8
}
pub fn is_empty(&self) -> bool {
self.bits.is_empty()
}
pub fn is_set(&self, i: usize) -> bool {
assert!(i < (self.bits.len() << 3));
unsafe { bit_util::get_bit_raw(self.bits.as_ptr(), i) }
}
pub fn buffer_ref(&self) -> &Buffer {
&self.bits
}
pub fn into_buffer(self) -> Buffer {
self.bits
}
pub fn get_buffer_memory_size(&self) -> usize {
self.bits.capacity()
}
pub fn get_array_memory_size(&self) -> usize {
self.bits.capacity() + mem::size_of_val(self)
}
}
impl<'a, 'b> BitAnd<&'b Bitmap> for &'a Bitmap {
type Output = Result<Bitmap>;
fn bitand(self, rhs: &'b Bitmap) -> Result<Bitmap> {
Ok(Bitmap::from((&self.bits & &rhs.bits)?))
}
}
impl<'a, 'b> BitOr<&'b Bitmap> for &'a Bitmap {
type Output = Result<Bitmap>;
fn bitor(self, rhs: &'b Bitmap) -> Result<Bitmap> {
Ok(Bitmap::from((&self.bits | &rhs.bits)?))
}
}
impl From<Buffer> for Bitmap {
fn from(buf: Buffer) -> Self {
Self { bits: buf }
}
}
impl PartialEq for Bitmap {
fn eq(&self, other: &Self) -> bool {
let self_len = self.bits.len();
let other_len = other.bits.len();
if self_len != other_len {
return false;
}
self.bits.as_slice()[..self_len] == other.bits.as_slice()[..self_len]
}
}
#[cfg(test)]
mod tests {
use super::*;
#[test]
fn test_bitmap_length() {
assert_eq!(512, Bitmap::new(63 * 8).bit_len());
assert_eq!(512, Bitmap::new(64 * 8).bit_len());
assert_eq!(1024, Bitmap::new(65 * 8).bit_len());
}
#[test]
fn test_bitwise_and() {
let bitmap1 = Bitmap::from(Buffer::from([0b01101010]));
let bitmap2 = Bitmap::from(Buffer::from([0b01001110]));
assert_eq!(
Bitmap::from(Buffer::from([0b01001010])),
(&bitmap1 & &bitmap2).unwrap()
);
}
#[test]
fn test_bitwise_or() {
let bitmap1 = Bitmap::from(Buffer::from([0b01101010]));
let bitmap2 = Bitmap::from(Buffer::from([0b01001110]));
assert_eq!(
Bitmap::from(Buffer::from([0b01101110])),
(&bitmap1 | &bitmap2).unwrap()
);
}
#[test]
fn test_bitmap_is_set() {
let bitmap = Bitmap::from(Buffer::from([0b01001010]));
assert!(!bitmap.is_set(0));
assert!(bitmap.is_set(1));
assert!(!bitmap.is_set(2));
assert!(bitmap.is_set(3));
assert!(!bitmap.is_set(4));
assert!(!bitmap.is_set(5));
assert!(bitmap.is_set(6));
assert!(!bitmap.is_set(7));
}
}