602 lines
15 KiB
Rust
602 lines
15 KiB
Rust
/*
|
|
Module: bitv
|
|
|
|
Bitvectors.
|
|
*/
|
|
|
|
export t;
|
|
export create;
|
|
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;
|
|
|
|
// FIXME: With recursive object types, we could implement binary methods like
|
|
// union, intersection, and difference. At that point, we could write
|
|
// an optimizing version of this module that produces a different obj
|
|
// for the case where nbits <= 32.
|
|
|
|
/*
|
|
Type: t
|
|
|
|
The bitvector type.
|
|
*/
|
|
type t = @{storage: [mutable uint], nbits: uint};
|
|
|
|
|
|
const uint_bits: uint = 32u + (1u << 32u >> 27u);
|
|
|
|
/*
|
|
Function: create
|
|
|
|
Constructs a bitvector.
|
|
|
|
Parameters:
|
|
nbits - The number of bits in the bitvector
|
|
init - If true then the bits are initialized to 1, otherwise 0
|
|
*/
|
|
fn create(nbits: uint, init: bool) -> t {
|
|
let elt = if init { !0u } else { 0u };
|
|
let storage = vec::init_elt_mut::<uint>(nbits / uint_bits + 1u, elt);
|
|
ret @{storage: storage, nbits: nbits};
|
|
}
|
|
|
|
fn process(v0: t, v1: t, op: fn(uint, uint) -> uint) -> bool {
|
|
let len = vec::len(v1.storage);
|
|
assert (vec::len(v0.storage) == len);
|
|
assert (v0.nbits == v1.nbits);
|
|
let changed = false;
|
|
uint::range(0u, len) {|i|
|
|
let w0 = v0.storage[i];
|
|
let w1 = v1.storage[i];
|
|
let w = op(w0, w1);
|
|
if w0 != w { changed = true; v0.storage[i] = w; }
|
|
};
|
|
ret changed;
|
|
}
|
|
|
|
|
|
fn lor(w0: uint, w1: uint) -> uint { ret w0 | w1; }
|
|
|
|
fn union(v0: t, v1: t) -> bool { let sub = lor; ret process(v0, v1, sub); }
|
|
|
|
fn land(w0: uint, w1: uint) -> uint { ret w0 & w1; }
|
|
|
|
/*
|
|
Function: intersect
|
|
|
|
Calculates the intersection of two bitvectors
|
|
|
|
Sets `v0` to the intersection of `v0` and `v1`
|
|
|
|
Preconditions:
|
|
|
|
Both bitvectors must be the same length
|
|
|
|
Returns:
|
|
|
|
True if `v0` was changed
|
|
*/
|
|
fn intersect(v0: t, v1: t) -> bool {
|
|
let sub = land;
|
|
ret process(v0, v1, sub);
|
|
}
|
|
|
|
fn right(_w0: uint, w1: uint) -> uint { ret w1; }
|
|
|
|
/*
|
|
Function: assign
|
|
|
|
Assigns the value of `v1` to `v0`
|
|
|
|
Preconditions:
|
|
|
|
Both bitvectors must be the same length
|
|
|
|
Returns:
|
|
|
|
True if `v0` was changed
|
|
*/
|
|
fn assign(v0: t, v1: t) -> bool { let sub = right; ret process(v0, v1, sub); }
|
|
|
|
/*
|
|
Function: clone
|
|
|
|
Makes a copy of a bitvector
|
|
*/
|
|
fn clone(v: t) -> t {
|
|
let storage = vec::init_elt_mut::<uint>(v.nbits / uint_bits + 1u, 0u);
|
|
let len = vec::len(v.storage);
|
|
uint::range(0u, len) {|i| storage[i] = v.storage[i]; };
|
|
ret @{storage: storage, nbits: v.nbits};
|
|
}
|
|
|
|
/*
|
|
Function: get
|
|
|
|
Retreive the value at index `i`
|
|
*/
|
|
pure fn get(v: t, i: uint) -> bool {
|
|
assert (i < v.nbits);
|
|
let bits = uint_bits;
|
|
let w = i / bits;
|
|
let b = i % bits;
|
|
let x = 1u & v.storage[w] >> b;
|
|
ret x == 1u;
|
|
}
|
|
|
|
// FIXME: This doesn't account for the actual size of the vectors,
|
|
// so it could end up comparing garbage bits
|
|
/*
|
|
Function: equal
|
|
|
|
Compares two bitvectors
|
|
|
|
Preconditions:
|
|
|
|
Both bitvectors must be the same length
|
|
|
|
Returns:
|
|
|
|
True if both bitvectors contain identical elements
|
|
*/
|
|
fn equal(v0: t, v1: t) -> bool {
|
|
// FIXME: when we can break or return from inside an iterator loop,
|
|
// we can eliminate this painful while-loop
|
|
|
|
let len = vec::len(v1.storage);
|
|
let i = 0u;
|
|
while i < len {
|
|
if v0.storage[i] != v1.storage[i] { ret false; }
|
|
i = i + 1u;
|
|
}
|
|
ret true;
|
|
}
|
|
|
|
/*
|
|
Function: clear
|
|
|
|
Set all bits to 0
|
|
*/
|
|
fn clear(v: t) {
|
|
uint::range(0u, vec::len(v.storage)) {|i| v.storage[i] = 0u; };
|
|
}
|
|
|
|
/*
|
|
Function: set_all
|
|
|
|
Set all bits to 1
|
|
*/
|
|
fn set_all(v: t) {
|
|
uint::range(0u, v.nbits) {|i| set(v, i, true); };
|
|
}
|
|
|
|
/*
|
|
Function: invert
|
|
|
|
Invert all bits
|
|
*/
|
|
fn invert(v: t) {
|
|
uint::range(0u, vec::len(v.storage)) {|i|
|
|
v.storage[i] = !v.storage[i];
|
|
};
|
|
}
|
|
|
|
/*
|
|
Function: difference
|
|
|
|
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.
|
|
|
|
Preconditions:
|
|
|
|
Both bitvectors must be the same length
|
|
|
|
Returns:
|
|
|
|
True if `v0` was changed
|
|
*/
|
|
fn difference(v0: t, v1: t) -> bool {
|
|
invert(v1);
|
|
let b = intersect(v0, v1);
|
|
invert(v1);
|
|
ret b;
|
|
}
|
|
|
|
/*
|
|
Function: set
|
|
|
|
Set the value of a bit at a given index
|
|
|
|
Preconditions:
|
|
|
|
`i` must be less than the length of the bitvector
|
|
*/
|
|
fn set(v: t, i: uint, x: bool) {
|
|
assert (i < v.nbits);
|
|
let bits = uint_bits;
|
|
let w = i / bits;
|
|
let b = i % bits;
|
|
let flag = 1u << b;
|
|
v.storage[w] = if x { v.storage[w] | flag } else { v.storage[w] & !flag };
|
|
}
|
|
|
|
|
|
/*
|
|
Function: is_true
|
|
|
|
Returns true if all bits are 1
|
|
*/
|
|
fn is_true(v: t) -> bool {
|
|
for i: uint in to_vec(v) { if i != 1u { ret false; } }
|
|
ret true;
|
|
}
|
|
|
|
|
|
/*
|
|
Function: is_false
|
|
|
|
Returns true if all bits are 0
|
|
*/
|
|
fn is_false(v: t) -> bool {
|
|
for i: uint in to_vec(v) { if i == 1u { ret false; } }
|
|
ret true;
|
|
}
|
|
|
|
fn init_to_vec(v: t, i: uint) -> uint { ret if get(v, i) { 1u } else { 0u }; }
|
|
|
|
/*
|
|
Function: to_vec
|
|
|
|
Converts the bitvector to a vector of uint with the same length. Each uint
|
|
in the resulting vector has either value 0u or 1u.
|
|
*/
|
|
fn to_vec(v: t) -> [uint] {
|
|
let sub = bind init_to_vec(v, _);
|
|
ret vec::init_fn::<uint>(v.nbits, sub);
|
|
}
|
|
|
|
/*
|
|
Function: to_str
|
|
|
|
Converts the bitvector to a string. The resulting string has the same
|
|
length as the bitvector, and each character is either '0' or '1'.
|
|
*/
|
|
fn to_str(v: t) -> str {
|
|
let rs = "";
|
|
for i: uint in to_vec(v) { if i == 1u { rs += "1"; } else { rs += "0"; } }
|
|
ret rs;
|
|
}
|
|
|
|
/*
|
|
Function: eq_vec
|
|
|
|
Compare a bitvector to a vector of uint. The uint vector is expected to
|
|
only contain the values 0u and 1u.
|
|
|
|
Preconditions:
|
|
|
|
Both the bitvector and vector must have the same length
|
|
*/
|
|
fn eq_vec(v0: t, v1: [uint]) -> bool {
|
|
assert (v0.nbits == vec::len::<uint>(v1));
|
|
let len = v0.nbits;
|
|
let i = 0u;
|
|
while i < len {
|
|
let w0 = get(v0, i);
|
|
let w1 = v1[i];
|
|
if !w0 && w1 != 0u || w0 && w1 == 0u { ret false; }
|
|
i = i + 1u;
|
|
}
|
|
ret true;
|
|
}
|
|
|
|
#[cfg(test)]
|
|
mod tests {
|
|
#[test]
|
|
fn test_0_elements() {
|
|
let act;
|
|
let exp;
|
|
act = create(0u, false);
|
|
exp = vec::init_elt::<uint>(0u, 0u);
|
|
assert (eq_vec(act, exp));
|
|
}
|
|
|
|
#[test]
|
|
fn test_1_element() {
|
|
let act;
|
|
act = create(1u, false);
|
|
assert (eq_vec(act, [0u]));
|
|
act = create(1u, true);
|
|
assert (eq_vec(act, [1u]));
|
|
}
|
|
|
|
#[test]
|
|
fn test_10_elements() {
|
|
let act;
|
|
// all 0
|
|
|
|
act = create(10u, false);
|
|
assert (eq_vec(act, [0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u]));
|
|
// all 1
|
|
|
|
act = create(10u, true);
|
|
assert (eq_vec(act, [1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u]));
|
|
// mixed
|
|
|
|
act = create(10u, false);
|
|
set(act, 0u, true);
|
|
set(act, 1u, true);
|
|
set(act, 2u, true);
|
|
set(act, 3u, true);
|
|
set(act, 4u, true);
|
|
assert (eq_vec(act, [1u, 1u, 1u, 1u, 1u, 0u, 0u, 0u, 0u, 0u]));
|
|
// mixed
|
|
|
|
act = create(10u, false);
|
|
set(act, 5u, true);
|
|
set(act, 6u, true);
|
|
set(act, 7u, true);
|
|
set(act, 8u, true);
|
|
set(act, 9u, true);
|
|
assert (eq_vec(act, [0u, 0u, 0u, 0u, 0u, 1u, 1u, 1u, 1u, 1u]));
|
|
// mixed
|
|
|
|
act = create(10u, false);
|
|
set(act, 0u, true);
|
|
set(act, 3u, true);
|
|
set(act, 6u, true);
|
|
set(act, 9u, true);
|
|
assert (eq_vec(act, [1u, 0u, 0u, 1u, 0u, 0u, 1u, 0u, 0u, 1u]));
|
|
}
|
|
|
|
#[test]
|
|
fn test_31_elements() {
|
|
let act;
|
|
// all 0
|
|
|
|
act = create(31u, false);
|
|
assert (eq_vec(act,
|
|
[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 = create(31u, true);
|
|
assert (eq_vec(act,
|
|
[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 = create(31u, false);
|
|
set(act, 0u, true);
|
|
set(act, 1u, true);
|
|
set(act, 2u, true);
|
|
set(act, 3u, true);
|
|
set(act, 4u, true);
|
|
set(act, 5u, true);
|
|
set(act, 6u, true);
|
|
set(act, 7u, true);
|
|
assert (eq_vec(act,
|
|
[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 = create(31u, false);
|
|
set(act, 16u, true);
|
|
set(act, 17u, true);
|
|
set(act, 18u, true);
|
|
set(act, 19u, true);
|
|
set(act, 20u, true);
|
|
set(act, 21u, true);
|
|
set(act, 22u, true);
|
|
set(act, 23u, true);
|
|
assert (eq_vec(act,
|
|
[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 = create(31u, false);
|
|
set(act, 24u, true);
|
|
set(act, 25u, true);
|
|
set(act, 26u, true);
|
|
set(act, 27u, true);
|
|
set(act, 28u, true);
|
|
set(act, 29u, true);
|
|
set(act, 30u, true);
|
|
assert (eq_vec(act,
|
|
[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 = create(31u, false);
|
|
set(act, 3u, true);
|
|
set(act, 17u, true);
|
|
set(act, 30u, true);
|
|
assert (eq_vec(act,
|
|
[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 act;
|
|
// all 0
|
|
|
|
act = create(32u, false);
|
|
assert (eq_vec(act,
|
|
[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 = create(32u, true);
|
|
assert (eq_vec(act,
|
|
[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 = create(32u, false);
|
|
set(act, 0u, true);
|
|
set(act, 1u, true);
|
|
set(act, 2u, true);
|
|
set(act, 3u, true);
|
|
set(act, 4u, true);
|
|
set(act, 5u, true);
|
|
set(act, 6u, true);
|
|
set(act, 7u, true);
|
|
assert (eq_vec(act,
|
|
[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 = create(32u, false);
|
|
set(act, 16u, true);
|
|
set(act, 17u, true);
|
|
set(act, 18u, true);
|
|
set(act, 19u, true);
|
|
set(act, 20u, true);
|
|
set(act, 21u, true);
|
|
set(act, 22u, true);
|
|
set(act, 23u, true);
|
|
assert (eq_vec(act,
|
|
[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 = create(32u, false);
|
|
set(act, 24u, true);
|
|
set(act, 25u, true);
|
|
set(act, 26u, true);
|
|
set(act, 27u, true);
|
|
set(act, 28u, true);
|
|
set(act, 29u, true);
|
|
set(act, 30u, true);
|
|
set(act, 31u, true);
|
|
assert (eq_vec(act,
|
|
[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 = create(32u, false);
|
|
set(act, 3u, true);
|
|
set(act, 17u, true);
|
|
set(act, 30u, true);
|
|
set(act, 31u, true);
|
|
assert (eq_vec(act,
|
|
[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 act;
|
|
// all 0
|
|
|
|
act = create(33u, false);
|
|
assert (eq_vec(act,
|
|
[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 = create(33u, true);
|
|
assert (eq_vec(act,
|
|
[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 = create(33u, false);
|
|
set(act, 0u, true);
|
|
set(act, 1u, true);
|
|
set(act, 2u, true);
|
|
set(act, 3u, true);
|
|
set(act, 4u, true);
|
|
set(act, 5u, true);
|
|
set(act, 6u, true);
|
|
set(act, 7u, true);
|
|
assert (eq_vec(act,
|
|
[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 = create(33u, false);
|
|
set(act, 16u, true);
|
|
set(act, 17u, true);
|
|
set(act, 18u, true);
|
|
set(act, 19u, true);
|
|
set(act, 20u, true);
|
|
set(act, 21u, true);
|
|
set(act, 22u, true);
|
|
set(act, 23u, true);
|
|
assert (eq_vec(act,
|
|
[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 = create(33u, false);
|
|
set(act, 24u, true);
|
|
set(act, 25u, true);
|
|
set(act, 26u, true);
|
|
set(act, 27u, true);
|
|
set(act, 28u, true);
|
|
set(act, 29u, true);
|
|
set(act, 30u, true);
|
|
set(act, 31u, true);
|
|
assert (eq_vec(act,
|
|
[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 = create(33u, false);
|
|
set(act, 3u, true);
|
|
set(act, 17u, true);
|
|
set(act, 30u, true);
|
|
set(act, 31u, true);
|
|
set(act, 32u, true);
|
|
assert (eq_vec(act,
|
|
[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]));
|
|
}
|
|
|
|
}
|
|
|
|
//
|
|
// Local Variables:
|
|
// mode: rust
|
|
// fill-column: 78;
|
|
// indent-tabs-mode: nil
|
|
// c-basic-offset: 4
|
|
// buffer-file-coding-system: utf-8-unix
|
|
// End:
|
|
//
|