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@@ -0,0 +1,100 @@ | ||
use crate::bitmap::{Bitmap, MutableBitmap}; | ||
use crate::storage::SharedStorage; | ||
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/// Used to build bitmaps bool-by-bool in sequential order. | ||
#[derive(Default, Clone)] | ||
pub struct BitmapBuilder { | ||
buf: u64, | ||
len: usize, | ||
cap: usize, | ||
set_bits: usize, | ||
bytes: Vec<u8>, | ||
} | ||
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impl BitmapBuilder { | ||
pub fn new() -> Self { | ||
Self::default() | ||
} | ||
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pub fn len(&self) -> usize { | ||
self.len | ||
} | ||
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pub fn capacity(&self) -> usize { | ||
self.cap | ||
} | ||
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pub fn with_capacity(bits: usize) -> Self { | ||
let bytes = Vec::with_capacity(bits.div_ceil(64) * 8); | ||
let words_available = bytes.capacity() / 8; | ||
Self { | ||
buf: 0, | ||
len: 0, | ||
cap: words_available * 64, | ||
set_bits: 0, | ||
bytes | ||
} | ||
} | ||
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#[inline(always)] | ||
pub fn reserve(&mut self, additional: usize) { | ||
if self.len + additional > self.cap { | ||
self.reserve_slow(additional) | ||
} | ||
} | ||
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#[cold] | ||
#[inline(never)] | ||
fn reserve_slow(&mut self, additional: usize) { | ||
let bytes_needed = (self.len + additional).div_ceil(64) * 8; | ||
self.bytes.reserve(bytes_needed - self.bytes.capacity()); | ||
let words_available = self.bytes.capacity() / 8; | ||
self.cap = words_available * 64; | ||
} | ||
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#[inline(always)] | ||
pub fn push(&mut self, x: bool) { | ||
self.reserve(1); | ||
unsafe { self.push_unchecked(x) } | ||
} | ||
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/// # Safety | ||
/// self.len() < self.capacity() must hold. | ||
#[inline(always)] | ||
pub unsafe fn push_unchecked(&mut self, x: bool) { | ||
debug_assert!(self.len < self.cap); | ||
self.buf |= (x as u64) << (self.len % 64); | ||
self.len += 1; | ||
if self.len % 64 == 0 { | ||
let p = self.bytes.as_mut_ptr().add(self.bytes.len()).cast::<u64>(); | ||
p.write_unaligned(self.buf.to_le()); | ||
self.bytes.set_len(self.bytes.len() + 8); | ||
self.set_bits += self.buf.count_ones() as usize; | ||
self.buf = 0; | ||
} | ||
} | ||
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/// # Safety | ||
/// May only be called once at the end. | ||
unsafe fn finish(&mut self) { | ||
if self.len % 64 != 0 { | ||
self.bytes.extend_from_slice(&self.buf.to_le_bytes()); | ||
self.set_bits += self.buf.count_ones() as usize; | ||
} | ||
} | ||
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pub fn into_mut(mut self) -> MutableBitmap { | ||
unsafe { | ||
self.finish(); | ||
MutableBitmap::from_vec(self.bytes, self.len) | ||
} | ||
} | ||
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pub fn freeze(mut self) -> Bitmap { | ||
unsafe { | ||
self.finish(); | ||
let storage = SharedStorage::from_vec(self.bytes); | ||
Bitmap::from_inner_unchecked(storage, 0, self.len, Some(self.len - self.set_bits)) | ||
} | ||
} | ||
} |
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@@ -19,3 +19,6 @@ pub use assign_ops::*; | |
pub mod utils; | ||
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pub mod bitmask; | ||
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mod builder; | ||
pub use builder::*; |