558 lines
15 KiB
Rust
558 lines
15 KiB
Rust
export bitv;
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export union;
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export intersect;
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export assign;
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export clone;
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export get;
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export equal;
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export clear;
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export set_all;
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export invert;
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export difference;
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export set;
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export is_true;
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export is_false;
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export to_vec;
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export to_str;
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export eq_vec;
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// FIXME (#2341): With recursive object types, we could implement binary
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// methods like union, intersection, and difference. At that point, we could
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// write an optimizing version of this module that produces a different obj
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// for the case where nbits <= 32.
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/// The bitvector type
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type bitv = @{storage: ~[mut uint], nbits: uint};
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const uint_bits: uint = 32u + (1u << 32u >> 27u);
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/**
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* Constructs a bitvector
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*
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* # Arguments
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*
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* * nbits - The number of bits in the bitvector
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* * init - If true then the bits are initialized to 1, otherwise 0
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*/
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fn bitv(nbits: uint, init: bool) -> bitv {
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let elt = if init { !0u } else { 0u };
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let storage = vec::to_mut(vec::from_elem(nbits / uint_bits + 1u, elt));
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ret @{storage: storage, nbits: nbits};
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}
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fn process(v0: bitv, v1: bitv, op: fn(uint, uint) -> uint) -> bool {
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let len = vec::len(v1.storage);
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assert (vec::len(v0.storage) == len);
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assert (v0.nbits == v1.nbits);
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let mut changed = false;
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for uint::range(0u, len) |i| {
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let w0 = v0.storage[i];
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let w1 = v1.storage[i];
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let w = op(w0, w1);
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if w0 != w { changed = true; v0.storage[i] = w; }
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};
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ret changed;
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}
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fn lor(w0: uint, w1: uint) -> uint { ret w0 | w1; }
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fn union(v0: bitv, v1: bitv) -> bool {
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let sub = lor; ret process(v0, v1, sub);
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}
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fn land(w0: uint, w1: uint) -> uint { ret w0 & w1; }
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/**
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* Calculates the intersection of two bitvectors
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*
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* Sets `v0` to the intersection of `v0` and `v1`. Both bitvectors must be the
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* same length. Returns 'true' if `v0` was changed.
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*/
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fn intersect(v0: bitv, v1: bitv) -> bool {
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let sub = land;
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ret process(v0, v1, sub);
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}
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fn right(_w0: uint, w1: uint) -> uint { ret w1; }
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/**
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* Assigns the value of `v1` to `v0`
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*
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* Both bitvectors must be the same length. Returns `true` if `v0` was changed
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*/
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fn assign(v0: bitv, v1: bitv) -> bool {
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let sub = right; ret process(v0, v1, sub);
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}
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/// Makes a copy of a bitvector
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fn clone(v: bitv) -> bitv {
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let storage = vec::to_mut(vec::from_elem(v.nbits / uint_bits + 1u, 0u));
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let len = vec::len(v.storage);
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for uint::range(0u, len) |i| { storage[i] = v.storage[i]; };
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ret @{storage: storage, nbits: v.nbits};
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}
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/// Retrieve the value at index `i`
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#[inline(always)]
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pure fn get(v: bitv, i: uint) -> bool {
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assert (i < v.nbits);
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let bits = uint_bits;
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let w = i / bits;
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let b = i % bits;
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let x = 1u & v.storage[w] >> b;
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ret x == 1u;
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}
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/**
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* Compares two bitvectors
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*
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* Both bitvectors must be the same length. Returns `true` if both bitvectors
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* contain identical elements.
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*/
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fn equal(v0: bitv, v1: bitv) -> bool {
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if v0.nbits != v1.nbits { ret false; }
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let len = vec::len(v1.storage);
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for uint::iterate(0u, len) |i| {
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if v0.storage[i] != v1.storage[i] { ret false; }
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}
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}
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/// Set all bits to 0
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#[inline(always)]
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fn clear(v: bitv) { for each_storage(v) |w| { w = 0u } }
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/// Set all bits to 1
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#[inline(always)]
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fn set_all(v: bitv) { for each_storage(v) |w| { w = !0u } }
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/// Invert all bits
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#[inline(always)]
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fn invert(v: bitv) { for each_storage(v) |w| { w = !w } }
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/**
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* Calculate the difference between two bitvectors
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*
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* Sets each element of `v0` to the value of that element minus the element
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* of `v1` at the same index. Both bitvectors must be the same length.
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*
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* Returns `true` if `v0` was changed.
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*/
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fn difference(v0: bitv, v1: bitv) -> bool {
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invert(v1);
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let b = intersect(v0, v1);
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invert(v1);
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ret b;
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}
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/**
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* Set the value of a bit at a given index
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*
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* `i` must be less than the length of the bitvector.
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*/
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#[inline(always)]
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fn set(v: bitv, i: uint, x: bool) {
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assert (i < v.nbits);
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let bits = uint_bits;
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let w = i / bits;
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let b = i % bits;
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let flag = 1u << b;
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v.storage[w] = if x { v.storage[w] | flag } else { v.storage[w] & !flag };
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}
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/// Returns true if all bits are 1
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fn is_true(v: bitv) -> bool {
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for each(v) |i| { if !i { ret false; } }
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ret true;
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}
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/// Returns true if all bits are 0
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fn is_false(v: bitv) -> bool {
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for each(v) |i| { if i { ret false; } }
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ret true;
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}
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fn init_to_vec(v: bitv, i: uint) -> uint {
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ret if get(v, i) { 1u } else { 0u };
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}
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/**
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* Converts the bitvector to a vector of uint with the same length.
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*
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* Each uint in the resulting vector has either value 0u or 1u.
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*/
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fn to_vec(v: bitv) -> ~[uint] {
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let sub = |x| init_to_vec(v, x);
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ret vec::from_fn::<uint>(v.nbits, sub);
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}
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#[inline(always)]
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fn each(v: bitv, f: fn(bool) -> bool) {
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let mut i = 0u;
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while i < v.nbits {
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if !f(get(v, i)) { break; }
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i = i + 1u;
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}
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}
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#[inline(always)]
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fn each_storage(v: bitv, op: fn(&uint) -> bool) {
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for uint::range(0u, vec::len(v.storage)) |i| {
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let mut w = v.storage[i];
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let b = !op(w);
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v.storage[i] = w;
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if !b { break; }
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}
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}
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/**
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* Converts the bitvector to a string.
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*
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* The resulting string has the same length as the bitvector, and each
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* character is either '0' or '1'.
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*/
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fn to_str(v: bitv) -> str {
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let mut rs = "";
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for each(v) |i| { if i { rs += "1"; } else { rs += "0"; } }
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ret rs;
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}
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/**
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* Compare a bitvector to a vector of uint
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*
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* The uint vector is expected to only contain the values 0u and 1u. Both the
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* bitvector and vector must have the same length
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*/
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fn eq_vec(v0: bitv, v1: ~[uint]) -> bool {
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assert (v0.nbits == vec::len::<uint>(v1));
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let len = v0.nbits;
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let mut i = 0u;
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while i < len {
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let w0 = get(v0, i);
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let w1 = v1[i];
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if !w0 && w1 != 0u || w0 && w1 == 0u { ret false; }
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i = i + 1u;
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}
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ret true;
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}
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#[cfg(test)]
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mod tests {
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#[test]
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fn test_to_str() {
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let zerolen = bitv(0u, false);
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assert to_str(zerolen) == "";
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let eightbits = bitv(8u, false);
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assert to_str(eightbits) == "00000000";
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}
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#[test]
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fn test_0_elements() {
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let mut act;
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let mut exp;
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act = bitv(0u, false);
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exp = vec::from_elem::<uint>(0u, 0u);
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assert (eq_vec(act, exp));
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}
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#[test]
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fn test_1_element() {
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let mut act;
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act = bitv(1u, false);
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assert (eq_vec(act, ~[0u]));
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act = bitv(1u, true);
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assert (eq_vec(act, ~[1u]));
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}
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#[test]
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fn test_10_elements() {
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let mut act;
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// all 0
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act = bitv(10u, false);
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assert (eq_vec(act, ~[0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u]));
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// all 1
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act = bitv(10u, true);
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assert (eq_vec(act, ~[1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u]));
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// mixed
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act = bitv(10u, false);
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set(act, 0u, true);
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set(act, 1u, true);
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set(act, 2u, true);
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set(act, 3u, true);
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set(act, 4u, true);
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assert (eq_vec(act, ~[1u, 1u, 1u, 1u, 1u, 0u, 0u, 0u, 0u, 0u]));
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// mixed
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act = bitv(10u, false);
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set(act, 5u, true);
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set(act, 6u, true);
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set(act, 7u, true);
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set(act, 8u, true);
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set(act, 9u, true);
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assert (eq_vec(act, ~[0u, 0u, 0u, 0u, 0u, 1u, 1u, 1u, 1u, 1u]));
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// mixed
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act = bitv(10u, false);
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set(act, 0u, true);
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set(act, 3u, true);
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set(act, 6u, true);
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set(act, 9u, true);
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assert (eq_vec(act, ~[1u, 0u, 0u, 1u, 0u, 0u, 1u, 0u, 0u, 1u]));
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}
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#[test]
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fn test_31_elements() {
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let mut act;
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// all 0
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act = bitv(31u, false);
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assert (eq_vec(act,
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~[0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u,
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0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u,
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0u, 0u, 0u, 0u, 0u]));
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// all 1
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act = bitv(31u, true);
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assert (eq_vec(act,
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~[1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u,
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1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u,
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1u, 1u, 1u, 1u, 1u]));
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// mixed
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act = bitv(31u, false);
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set(act, 0u, true);
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set(act, 1u, true);
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set(act, 2u, true);
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set(act, 3u, true);
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set(act, 4u, true);
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set(act, 5u, true);
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set(act, 6u, true);
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set(act, 7u, true);
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assert (eq_vec(act,
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~[1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 0u, 0u, 0u, 0u, 0u,
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0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u,
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0u, 0u, 0u, 0u, 0u]));
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// mixed
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act = bitv(31u, false);
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set(act, 16u, true);
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set(act, 17u, true);
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set(act, 18u, true);
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set(act, 19u, true);
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set(act, 20u, true);
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set(act, 21u, true);
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set(act, 22u, true);
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set(act, 23u, true);
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assert (eq_vec(act,
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~[0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u,
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0u, 0u, 0u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 0u, 0u,
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0u, 0u, 0u, 0u, 0u]));
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// mixed
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act = bitv(31u, false);
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set(act, 24u, true);
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set(act, 25u, true);
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set(act, 26u, true);
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set(act, 27u, true);
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set(act, 28u, true);
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set(act, 29u, true);
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set(act, 30u, true);
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assert (eq_vec(act,
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~[0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u,
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0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 1u, 1u,
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1u, 1u, 1u, 1u, 1u]));
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// mixed
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act = bitv(31u, false);
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set(act, 3u, true);
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set(act, 17u, true);
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set(act, 30u, true);
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assert (eq_vec(act,
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~[0u, 0u, 0u, 1u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u,
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0u, 0u, 0u, 0u, 1u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u,
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0u, 0u, 0u, 0u, 1u]));
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}
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#[test]
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fn test_32_elements() {
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let mut act;
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// all 0
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act = bitv(32u, false);
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assert (eq_vec(act,
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~[0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u,
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0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u,
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0u, 0u, 0u, 0u, 0u, 0u]));
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// all 1
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act = bitv(32u, true);
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assert (eq_vec(act,
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~[1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u,
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1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u,
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1u, 1u, 1u, 1u, 1u, 1u]));
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// mixed
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act = bitv(32u, false);
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set(act, 0u, true);
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set(act, 1u, true);
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set(act, 2u, true);
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set(act, 3u, true);
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set(act, 4u, true);
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set(act, 5u, true);
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set(act, 6u, true);
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set(act, 7u, true);
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assert (eq_vec(act,
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~[1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 0u, 0u, 0u, 0u, 0u,
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0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u,
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0u, 0u, 0u, 0u, 0u, 0u]));
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// mixed
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act = bitv(32u, false);
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set(act, 16u, true);
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set(act, 17u, true);
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set(act, 18u, true);
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set(act, 19u, true);
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set(act, 20u, true);
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set(act, 21u, true);
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set(act, 22u, true);
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set(act, 23u, true);
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assert (eq_vec(act,
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~[0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u,
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0u, 0u, 0u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 1u, 0u, 0u,
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0u, 0u, 0u, 0u, 0u, 0u]));
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// mixed
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act = bitv(32u, false);
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set(act, 24u, true);
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set(act, 25u, true);
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set(act, 26u, true);
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set(act, 27u, true);
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set(act, 28u, true);
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set(act, 29u, true);
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set(act, 30u, true);
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set(act, 31u, true);
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assert (eq_vec(act,
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~[0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u,
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0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 1u, 1u,
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1u, 1u, 1u, 1u, 1u, 1u]));
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// mixed
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act = bitv(32u, false);
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set(act, 3u, true);
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set(act, 17u, true);
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set(act, 30u, true);
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set(act, 31u, true);
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assert (eq_vec(act,
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~[0u, 0u, 0u, 1u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u,
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0u, 0u, 0u, 0u, 1u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u,
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0u, 0u, 0u, 0u, 1u, 1u]));
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}
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#[test]
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fn test_33_elements() {
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let mut act;
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// all 0
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act = bitv(33u, false);
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assert (eq_vec(act,
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~[0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u, 0u,
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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 (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 = bitv(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 = bitv(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 = bitv(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 = bitv(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]));
|
|
}
|
|
|
|
#[test]
|
|
fn test_equal_differing_sizes() {
|
|
let v0 = bitv(10u, false);
|
|
let v1 = bitv(11u, false);
|
|
assert !equal(v0, v1);
|
|
}
|
|
|
|
#[test]
|
|
fn test_equal_greatly_differing_sizes() {
|
|
let v0 = bitv(10u, false);
|
|
let v1 = bitv(110u, false);
|
|
assert !equal(v0, v1);
|
|
}
|
|
|
|
}
|
|
|
|
//
|
|
// Local Variables:
|
|
// mode: rust
|
|
// fill-column: 78;
|
|
// indent-tabs-mode: nil
|
|
// c-basic-offset: 4
|
|
// buffer-file-coding-system: utf-8-unix
|
|
// End:
|
|
//
|