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created a first draft of the bit-set library needed for typestate
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Dave Herman
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Oct 21, 2010
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@@ -28,6 +28,7 @@ mod driver { | |
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mod util { | ||
mod common; | ||
mod bits; | ||
} | ||
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auth driver.rustc.main = state; | ||
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@@ -0,0 +1,185 @@ | ||
import std._uint; | ||
import std._int; | ||
import std._vec; | ||
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// 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. | ||
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state type t = rec(vec[mutable uint] storage, uint nbits); | ||
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// FIXME: we should bind std.max_int | ||
fn is32bit() -> bool { | ||
let uint n = 0xffffffffu; | ||
ret (n + 1u) == 0u; | ||
} | ||
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fn uint_bits() -> uint { | ||
if (is32bit()) { | ||
ret 31u; | ||
} else { | ||
ret 63u; | ||
} | ||
} | ||
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// FIXME: this should be state | ||
fn create(uint nbits, bool init) -> t { | ||
auto elt; | ||
if (init) { | ||
elt = 1u; | ||
} else { | ||
elt = 0u; | ||
} | ||
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ret rec(storage = _vec.init_elt[mutable uint](nbits / uint_bits() + 1u, elt), | ||
nbits = nbits); | ||
} | ||
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// FIXME: this should be state | ||
fn process(fn(uint, uint) -> uint op, t v0, t v1) -> bool { | ||
auto len = _vec.len[mutable uint](v1.storage); | ||
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check (_vec.len[mutable uint](v0.storage) == len); | ||
check (v0.nbits == v1.nbits); | ||
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auto changed = false; | ||
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for each (uint i in _uint.range(0u, len)) { | ||
auto w0 = v0.storage.(i); | ||
auto w1 = v1.storage.(i); | ||
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auto w = op(w0, w1); | ||
if (w0 != w) { | ||
changed = true; | ||
v0.storage.(i) = w; | ||
} | ||
} | ||
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ret changed; | ||
} | ||
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fn lor(uint w0, uint w1) -> uint { | ||
ret w0 | w1; | ||
} | ||
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// FIXME: this should be state | ||
fn union(t v0, t v1) -> bool { | ||
auto sub = lor; | ||
ret process(sub, v0, v1); | ||
} | ||
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fn land(uint w0, uint w1) -> uint { | ||
ret w0 & w1; | ||
} | ||
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// FIXME: this should be state | ||
fn intersect(t v0, t v1) -> bool { | ||
auto sub = land; | ||
ret process(sub, v0, v1); | ||
} | ||
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fn right(uint w0, uint w1) -> uint { | ||
ret w1; | ||
} | ||
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// FIXME: this should be state | ||
fn copy(t v0, t v1) -> bool { | ||
auto sub = right; | ||
ret process(sub, v0, v1); | ||
} | ||
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// FIXME: this should be state | ||
fn get(t v, uint i) -> bool { | ||
check (i < v.nbits); | ||
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auto bits = uint_bits(); | ||
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auto w = i / bits; | ||
auto b = i % bits; | ||
auto x = 1u & (v.storage.(w) >> b); | ||
ret x == 1u; | ||
} | ||
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// FIXME: this should be state | ||
fn equal(t v0, t v1) -> bool { | ||
// FIXME: when we can break or return from inside an iterator loop, | ||
// we can eliminate this painful while-loop | ||
auto len = _vec.len[mutable uint](v1.storage); | ||
auto i = 0u; | ||
while (i < len) { | ||
if (v0.storage.(i) != v1.storage.(i)) { | ||
ret false; | ||
} | ||
i = i + 1u; | ||
} | ||
ret true; | ||
} | ||
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// FIXME: this should be state | ||
fn clear(t v) { | ||
for each (uint i in _uint.range(0u, _vec.len[mutable uint](v.storage))) { | ||
v.storage.(i) = 0u; | ||
} | ||
} | ||
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// FIXME: this should be state | ||
fn invert(t v) { | ||
for each (uint i in _uint.range(0u, _vec.len[mutable uint](v.storage))) { | ||
v.storage.(i) = ~v.storage.(i); | ||
} | ||
} | ||
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// FIXME: this should be state | ||
/* v0 = v0 - v1 */ | ||
fn difference(t v0, t v1) -> bool { | ||
invert(v1); | ||
auto b = intersect(v0, v1); | ||
invert(v1); | ||
ret b; | ||
} | ||
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// FIXME: this should be state | ||
fn set(t v, uint i, bool x) { | ||
check (i < v.nbits); | ||
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auto bits = uint_bits(); | ||
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auto w = i / bits; | ||
auto b = i % bits; | ||
auto w0 = v.storage.(w); | ||
auto flag = 1u << b; | ||
if (x) { | ||
v.storage.(w) = v.storage.(w) | flag; | ||
} else { | ||
v.storage.(w) = v.storage.(w) & ~flag; | ||
} | ||
} | ||
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// FIXME: this should be state | ||
fn init_to_vec(t v, uint i) -> uint { | ||
if (get(v, i)) { | ||
ret 1u; | ||
} else { | ||
ret 0u; | ||
} | ||
} | ||
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// FIXME: this should be state | ||
fn to_vec(t v) -> vec[uint] { | ||
auto sub = bind init_to_vec(v, _); | ||
ret _vec.init_fn[uint](sub, v.nbits); | ||
} | ||
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// | ||
// Local Variables: | ||
// mode: rust | ||
// fill-column: 78; | ||
// indent-tabs-mode: nil | ||
// c-basic-offset: 4 | ||
// buffer-file-coding-system: utf-8-unix | ||
// compile-command: "make -k -C ../.. 2>&1 | sed -e 's/\\/x\\//x:\\//g'"; | ||
// End: | ||
// |