rust/src/libstd/bitv.rs
2012-08-08 18:19:24 -07:00

746 lines
20 KiB
Rust

import vec::{to_mut, from_elem};
export bitv;
export union;
export intersect;
export assign;
export clone;
export get;
export equal;
export clear;
export set_all;
export invert;
export difference;
export set;
export is_true;
export is_false;
export to_vec;
export to_str;
export eq_vec;
export methods;
class small_bitv {
let mut bits: u32;
new(bits: u32) { self.bits = bits; }
priv {
#[inline(always)]
fn bits_op(right_bits: u32, f: fn(u32, u32) -> u32) -> bool {
let old_b: u32 = self.bits;
let new_b = f(old_b, right_bits);
self.bits = new_b;
old_b != new_b
}
}
#[inline(always)]
fn union(s: &small_bitv) -> bool {
self.bits_op(s.bits, |u1, u2| { u1 | u2 })
}
#[inline(always)]
fn intersect(s: &small_bitv) -> bool {
self.bits_op(s.bits, |u1, u2| { u1 & u2 })
}
#[inline(always)]
fn become(s: &small_bitv) -> bool {
let old = self.bits;
self.bits = s.bits;
old != self.bits
}
#[inline(always)]
fn difference(s: &small_bitv) -> bool {
let old = self.bits;
self.bits &= !s.bits;
old != self.bits
}
#[inline(always)]
pure fn get(i: uint) -> bool {
(self.bits & (1 << i)) != 0
}
#[inline(always)]
fn set(i: uint, x: bool) {
if x {
self.bits |= 1<<i;
}
else {
self.bits &= !(i as u32);
}
}
#[inline(always)]
fn equals(b: &small_bitv) -> bool { self.bits == b.bits }
#[inline(always)]
fn clear() { self.bits = 0; }
#[inline(always)]
fn set_all() { self.bits = !0; }
#[inline(always)]
fn is_true() -> bool { self.bits == !0 }
#[inline(always)]
fn is_false() -> bool { self.bits == 0 }
#[inline(always)]
fn invert() { self.bits = !self.bits; }
}
class big_bitv {
// only mut b/c of clone and lack of other constructor
let mut storage: ~[mut uint];
new(-storage: ~[mut uint]) {
self.storage <- storage;
}
priv {
#[inline(always)]
fn process(b: &big_bitv, op: fn(uint, uint) -> uint) -> bool {
let len = b.storage.len();
assert (self.storage.len() == len);
let mut changed = false;
do uint::range(0, len) |i| {
let w0 = self.storage[i];
let w1 = b.storage[i];
let w = op(w0, w1);
if w0 != w unchecked { changed = true; self.storage[i] = w; };
true
};
changed
}
}
#[inline(always)]
fn each_storage(op: fn(&uint) -> bool) {
for uint::range(0, self.storage.len()) |i| {
let mut w = self.storage[i];
let b = !op(w);
self.storage[i] = w;
if !b { break; }
}
}
#[inline(always)]
fn invert() { for self.each_storage() |w| { w = !w } }
#[inline(always)]
fn union(b: &big_bitv) -> bool { self.process(b, lor) }
#[inline(always)]
fn intersect(b: &big_bitv) -> bool { self.process(b, land) }
#[inline(always)]
fn become(b: &big_bitv) -> bool { self.process(b, right) }
#[inline(always)]
fn difference(b: &big_bitv) -> bool {
self.invert();
let b = self.intersect(b);
self.invert();
b
}
#[inline(always)]
pure fn get(i: uint) -> bool {
let w = i / uint_bits;
let b = i % uint_bits;
let x = 1 & self.storage[w] >> b;
x == 1
}
#[inline(always)]
fn set(i: uint, x: bool) {
let w = i / uint_bits;
let b = i % uint_bits;
let flag = 1 << b;
self.storage[w] = if x { self.storage[w] | flag }
else { self.storage[w] & !flag };
}
#[inline(always)]
fn equals(b: &big_bitv) -> bool {
let len = b.storage.len();
for uint::iterate(0, len) |i| {
if self.storage[i] != b.storage[i] { return false; }
}
}
}
enum a_bitv { big(~big_bitv), small(~small_bitv) }
enum op {union, intersect, assign, difference}
// The bitvector type
class bitv {
let rep: a_bitv;
let nbits: uint;
new(nbits: uint, init: bool) {
self.nbits = nbits;
if nbits <= 32 {
self.rep = small(~small_bitv(if init {!0} else {0}));
}
else {
let s = to_mut(from_elem(nbits / uint_bits + 1,
if init {!0} else {0}));
self.rep = big(~big_bitv(s));
};
}
priv {
fn die() -> ! {
fail ~"Tried to do operation on bit vectors with \
different sizes";
}
#[inline(always)]
fn do_op(op: op, other: &bitv) -> bool {
if self.nbits != other.nbits {
self.die();
}
match self.rep {
small(s) => match other.rep {
small(s1) => match op {
union => s.union(s1),
intersect => s.intersect(s1),
assign => s.become(s1),
difference => s.difference(s1)
},
big(s1) => self.die()
},
big(s) => match other.rep {
small(_) => self.die(),
big(s1) => match op {
union => s.union(s1),
intersect => s.intersect(s1),
assign => s.become(s1),
difference => s.difference(s1)
}
}
}
}
}
/**
* Calculates the union of two bitvectors
*
* Sets `self` to the union of `self` and `v1`. Both bitvectors must be
* the same length. Returns 'true' if `self` changed.
*/
#[inline(always)]
fn union(v1: &bitv) -> bool { self.do_op(union, v1) }
/**
* Calculates the intersection of two bitvectors
*
* Sets `self` to the intersection of `self` and `v1`. Both bitvectors must be
* the same length. Returns 'true' if `self` changed.
*/
#[inline(always)]
fn intersect(v1: &bitv) -> bool { self.do_op(intersect, v1) }
/**
* Assigns the value of `v1` to `self`
*
* Both bitvectors must be the same length. Returns `true` if `self` was
* changed
*/
#[inline(always)]
fn assign(v: &bitv) -> bool { self.do_op(assign, v) }
/// Makes a copy of a bitvector
#[inline(always)]
fn clone() -> ~bitv {
~match self.rep {
small(b) => {
bitv{nbits: self.nbits, rep: small(~small_bitv{bits: b.bits})}
}
big(b) => {
let st = to_mut(from_elem(self.nbits / uint_bits + 1, 0));
let len = st.len();
for uint::range(0, len) |i| { st[i] = b.storage[i]; };
bitv{nbits: self.nbits, rep: big(~big_bitv{storage: st})}
}
}
}
/// Retrieve the value at index `i`
#[inline(always)]
pure fn get(i: uint) -> bool {
assert (i < self.nbits);
match self.rep {
big(b) => b.get(i),
small(s) => s.get(i)
}
}
/**
* Set the value of a bit at a given index
*
* `i` must be less than the length of the bitvector.
*/
#[inline(always)]
fn set(i: uint, x: bool) {
assert (i < self.nbits);
match self.rep {
big(b) => b.set(i, x),
small(s) => s.set(i, x)
}
}
/**
* Compares two bitvectors
*
* Both bitvectors must be the same length. Returns `true` if both bitvectors
* contain identical elements.
*/
#[inline(always)]
fn equal(v1: bitv) -> bool {
if self.nbits != v1.nbits { return false; }
match self.rep {
small(b) => match v1.rep {
small(b1) => b.equals(b1),
_ => false
},
big(s) => match v1.rep {
big(s1) => s.equals(s1),
small(_) => return false
}
}
}
/// Set all bits to 0
#[inline(always)]
fn clear() {
match self.rep {
small(b) => b.clear(),
big(s) => for s.each_storage() |w| { w = 0u }
}
}
/// Set all bits to 1
#[inline(always)]
fn set_all() {
match self.rep {
small(b) => b.set_all(),
big(s) => for s.each_storage() |w| { w = !0u } }
}
/// Invert all bits
#[inline(always)]
fn invert() {
match self.rep {
small(b) => b.invert(),
big(s) => for s.each_storage() |w| { w = !w } }
}
/**
* Calculate the difference between two bitvectors
*
* Sets each element of `v0` to the value of that element minus the element
* of `v1` at the same index. Both bitvectors must be the same length.
*
* Returns `true` if `v0` was changed.
*/
#[inline(always)]
fn difference(v: ~bitv) -> bool { self.do_op(difference, v) }
/// Returns true if all bits are 1
#[inline(always)]
fn is_true() -> bool {
match self.rep {
small(b) => b.is_true(),
_ => {
for self.each() |i| { if !i { return false; } }
true
}
}
}
#[inline(always)]
fn each(f: fn(bool) -> bool) {
let mut i = 0;
while i < self.nbits {
if !f(self.get(i)) { break; }
i += 1;
}
}
/// Returns true if all bits are 0
fn is_false() -> bool {
match self.rep {
small(b) => b.is_false(),
big(_) => {
for self.each() |i| { if i { return false; } }
true
}
}
}
fn init_to_vec(i: uint) -> uint {
return if self.get(i) { 1 } else { 0 };
}
/**
* Converts `self` to a vector of uint with the same length.
*
* Each uint in the resulting vector has either value 0u or 1u.
*/
fn to_vec() -> ~[uint] {
vec::from_fn(self.nbits, |x| self.init_to_vec(x))
}
/**
* Converts `self` to a string.
*
* The resulting string has the same length as `self`, and each
* character is either '0' or '1'.
*/
fn to_str() -> ~str {
let mut rs = ~"";
for self.each() |i| { if i { rs += ~"1"; } else { rs += ~"0"; } };
rs
}
/**
* Compare a bitvector to a vector of uint
*
* The uint vector is expected to only contain the values 0u and 1u. Both the
* bitvector and vector must have the same length
*/
fn eq_vec(v: ~[uint]) -> bool {
assert self.nbits == v.len();
let mut i = 0;
while i < self.nbits {
let w0 = self.get(i);
let w1 = v[i];
if !w0 && w1 != 0u || w0 && w1 == 0u { return false; }
i = i + 1;
}
true
}
fn ones(f: fn(uint) -> bool) {
for uint::range(0, self.nbits) |i| {
if self.get(i) {
if !f(i) { break }
}
}
}
} // end of bitv class
const uint_bits: uint = 32u + (1u << 32u >> 27u);
pure fn lor(w0: uint, w1: uint) -> uint { return w0 | w1; }
pure fn land(w0: uint, w1: uint) -> uint { return w0 & w1; }
pure fn right(_w0: uint, w1: uint) -> uint { return w1; }
impl bitv: ops::index<uint,bool> {
pure fn index(&&i: uint) -> bool {
self.get(i)
}
}
#[cfg(test)]
mod tests {
#[test]
fn test_to_str() {
let zerolen = bitv(0u, false);
assert zerolen.to_str() == ~"";
let eightbits = bitv(8u, false);
assert eightbits.to_str() == ~"00000000";
}
#[test]
fn test_0_elements() {
let mut act;
let mut exp;
act = bitv(0u, false);
exp = vec::from_elem::<uint>(0u, 0u);
assert act.eq_vec(exp);
}
#[test]
fn test_1_element() {
let mut act;
act = bitv(1u, false);
assert act.eq_vec(~[0u]);
act = bitv(1u, true);
assert act.eq_vec(~[1u]);
}
#[test]
fn test_10_elements() {
let mut act;
// all 0
act = bitv(10u, false);
assert (act.eq_vec(~[0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u]));
// all 1
act = bitv(10u, true);
assert (act.eq_vec(~[1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u]));
// mixed
act = bitv(10u, false);
act.set(0u, true);
act.set(1u, true);
act.set(2u, true);
act.set(3u, true);
act.set(4u, true);
assert (act.eq_vec(~[1u, 1u, 1u, 1u, 1u, 0u, 0u, 0u, 0u, 0u]));
// mixed
act = bitv(10u, false);
act.set(5u, true);
act.set(6u, true);
act.set(7u, true);
act.set(8u, true);
act.set(9u, true);
assert (act.eq_vec(~[0u, 0u, 0u, 0u, 0u, 1u, 1u, 1u, 1u, 1u]));
// mixed
act = bitv(10u, false);
act.set(0u, true);
act.set(3u, true);
act.set(6u, true);
act.set(9u, true);
assert (act.eq_vec(~[1u, 0u, 0u, 1u, 0u, 0u, 1u, 0u, 0u, 1u]));
}
#[test]
fn test_31_elements() {
let mut act;
// all 0
act = bitv(31u, false);
assert (act.eq_vec(
~[0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u,
0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u,
0u, 0u, 0u, 0u, 0u]));
// all 1
act = bitv(31u, true);
assert (act.eq_vec(
~[1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u,
1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u,
1u, 1u, 1u, 1u, 1u]));
// mixed
act = bitv(31u, false);
act.set(0u, true);
act.set(1u, true);
act.set(2u, true);
act.set(3u, true);
act.set(4u, true);
act.set(5u, true);
act.set(6u, true);
act.set(7u, true);
assert (act.eq_vec(
~[1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 0u, 0u, 0u, 0u, 0u,
0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u,
0u, 0u, 0u, 0u, 0u]));
// mixed
act = bitv(31u, false);
act.set(16u, true);
act.set(17u, true);
act.set(18u, true);
act.set(19u, true);
act.set(20u, true);
act.set(21u, true);
act.set(22u, true);
act.set(23u, true);
assert (act.eq_vec(
~[0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u,
0u, 0u, 0u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 0u, 0u,
0u, 0u, 0u, 0u, 0u]));
// mixed
act = bitv(31u, false);
act.set(24u, true);
act.set(25u, true);
act.set(26u, true);
act.set(27u, true);
act.set(28u, true);
act.set(29u, true);
act.set(30u, true);
assert (act.eq_vec(
~[0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u,
0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 1u, 1u,
1u, 1u, 1u, 1u, 1u]));
// mixed
act = bitv(31u, false);
act.set(3u, true);
act.set(17u, true);
act.set(30u, true);
assert (act.eq_vec(
~[0u, 0u, 0u, 1u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u,
0u, 0u, 0u, 0u, 1u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u,
0u, 0u, 0u, 0u, 1u]));
}
#[test]
fn test_32_elements() {
let mut act;
// all 0
act = bitv(32u, false);
assert (act.eq_vec(
~[0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u,
0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u,
0u, 0u, 0u, 0u, 0u, 0u]));
// all 1
act = bitv(32u, true);
assert (act.eq_vec(
~[1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u,
1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u,
1u, 1u, 1u, 1u, 1u, 1u]));
// mixed
act = bitv(32u, false);
act.set(0u, true);
act.set(1u, true);
act.set(2u, true);
act.set(3u, true);
act.set(4u, true);
act.set(5u, true);
act.set(6u, true);
act.set(7u, true);
assert (act.eq_vec(
~[1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 0u, 0u, 0u, 0u, 0u,
0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u,
0u, 0u, 0u, 0u, 0u, 0u]));
// mixed
act = bitv(32u, false);
act.set(16u, true);
act.set(17u, true);
act.set(18u, true);
act.set(19u, true);
act.set(20u, true);
act.set(21u, true);
act.set(22u, true);
act.set(23u, true);
assert (act.eq_vec(
~[0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u,
0u, 0u, 0u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 0u, 0u,
0u, 0u, 0u, 0u, 0u, 0u]));
// mixed
act = bitv(32u, false);
act.set(24u, true);
act.set(25u, true);
act.set(26u, true);
act.set(27u, true);
act.set(28u, true);
act.set(29u, true);
act.set(30u, true);
act.set(31u, true);
assert (act.eq_vec(
~[0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u,
0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 1u, 1u,
1u, 1u, 1u, 1u, 1u, 1u]));
// mixed
act = bitv(32u, false);
act.set(3u, true);
act.set(17u, true);
act.set(30u, true);
act.set(31u, true);
assert (act.eq_vec(
~[0u, 0u, 0u, 1u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u,
0u, 0u, 0u, 0u, 1u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u,
0u, 0u, 0u, 0u, 1u, 1u]));
}
#[test]
fn test_33_elements() {
let mut act;
// all 0
act = bitv(33u, false);
assert (act.eq_vec(
~[0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u,
0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u,
0u, 0u, 0u, 0u, 0u, 0u, 0u]));
// all 1
act = bitv(33u, true);
assert (act.eq_vec(
~[1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u,
1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u,
1u, 1u, 1u, 1u, 1u, 1u, 1u]));
// mixed
act = bitv(33u, false);
act.set(0u, true);
act.set(1u, true);
act.set(2u, true);
act.set(3u, true);
act.set(4u, true);
act.set(5u, true);
act.set(6u, true);
act.set(7u, true);
assert (act.eq_vec(
~[1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 0u, 0u, 0u, 0u, 0u,
0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u,
0u, 0u, 0u, 0u, 0u, 0u, 0u]));
// mixed
act = bitv(33u, false);
act.set(16u, true);
act.set(17u, true);
act.set(18u, true);
act.set(19u, true);
act.set(20u, true);
act.set(21u, true);
act.set(22u, true);
act.set(23u, true);
assert (act.eq_vec(
~[0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u,
0u, 0u, 0u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 0u, 0u,
0u, 0u, 0u, 0u, 0u, 0u, 0u]));
// mixed
act = bitv(33u, false);
act.set(24u, true);
act.set(25u, true);
act.set(26u, true);
act.set(27u, true);
act.set(28u, true);
act.set(29u, true);
act.set(30u, true);
act.set(31u, true);
assert (act.eq_vec(
~[0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u,
0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 1u, 1u,
1u, 1u, 1u, 1u, 1u, 1u, 0u]));
// mixed
act = bitv(33u, false);
act.set(3u, true);
act.set(17u, true);
act.set(30u, true);
act.set(31u, true);
act.set(32u, true);
assert (act.eq_vec(
~[0u, 0u, 0u, 1u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u,
0u, 0u, 0u, 0u, 1u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u,
0u, 0u, 0u, 0u, 1u, 1u, 1u]));
}
#[test]
fn test_equal_differing_sizes() {
let v0 = bitv(10u, false);
let v1 = bitv(11u, false);
assert !v0.equal(v1);
}
#[test]
fn test_equal_greatly_differing_sizes() {
let v0 = bitv(10u, false);
let v1 = bitv(110u, false);
assert !v0.equal(v1);
}
}
//
// Local Variables:
// mode: rust
// fill-column: 78;
// indent-tabs-mode: nil
// c-basic-offset: 4
// buffer-file-coding-system: utf-8-unix
// End:
//