117 lines
3.5 KiB
Rust
117 lines
3.5 KiB
Rust
|
|
|
|
|
|
/**
|
|
* A deque, for fun. Untested as of yet. Likely buggy.
|
|
*/
|
|
type t[T] =
|
|
obj {
|
|
fn size() -> uint ;
|
|
fn add_front(&T) ;
|
|
fn add_back(&T) ;
|
|
fn pop_front() -> T ;
|
|
fn pop_back() -> T ;
|
|
fn peek_front() -> T ;
|
|
fn peek_back() -> T ;
|
|
fn get(int) -> T ;
|
|
};
|
|
|
|
fn create[T]() -> t[T] {
|
|
type cell[T] = option::t[T];
|
|
|
|
let uint initial_capacity = 32u; // 2^5
|
|
/**
|
|
* Grow is only called on full elts, so nelts is also len(elts), unlike
|
|
* elsewhere.
|
|
*/
|
|
|
|
fn grow[T](uint nelts, uint lo, vec[mutable cell[T]] elts) ->
|
|
vec[mutable cell[T]] {
|
|
assert (nelts == vec::len(elts));
|
|
// FIXME: Making the vector argument an alias is a workaround for
|
|
// issue #375
|
|
|
|
fn fill[T](uint i, uint nelts, uint lo, &vec[mutable cell[T]] old) ->
|
|
cell[T] {
|
|
ret if (i < nelts) {
|
|
old.((lo + i) % nelts)
|
|
} else { option::none };
|
|
}
|
|
let uint nalloc = uint::next_power_of_two(nelts + 1u);
|
|
let vec::init_op[cell[T]] copy_op = bind fill[T](_, nelts, lo, elts);
|
|
ret vec::init_fn_mut[cell[T]](copy_op, nalloc);
|
|
}
|
|
fn get[T](vec[mutable cell[T]] elts, uint i) -> T {
|
|
ret alt (elts.(i)) {
|
|
case (option::some(?t)) { t }
|
|
case (_) { fail }
|
|
};
|
|
}
|
|
obj deque[T](mutable uint nelts,
|
|
mutable uint lo,
|
|
mutable uint hi,
|
|
mutable vec[mutable cell[T]] elts) {
|
|
fn size() -> uint { ret nelts; }
|
|
fn add_front(&T t) {
|
|
let uint oldlo = lo;
|
|
if (lo == 0u) {
|
|
lo = vec::len[cell[T]](elts) - 1u;
|
|
} else { lo -= 1u; }
|
|
if (lo == hi) {
|
|
elts = grow[T](nelts, oldlo, elts);
|
|
lo = vec::len[cell[T]](elts) - 1u;
|
|
hi = nelts;
|
|
}
|
|
elts.(lo) = option::some[T](t);
|
|
nelts += 1u;
|
|
}
|
|
fn add_back(&T t) {
|
|
if (lo == hi && nelts != 0u) {
|
|
elts = grow[T](nelts, lo, elts);
|
|
lo = 0u;
|
|
hi = nelts;
|
|
}
|
|
elts.(hi) = option::some[T](t);
|
|
hi = (hi + 1u) % vec::len[cell[T]](elts);
|
|
nelts += 1u;
|
|
}
|
|
|
|
/**
|
|
* We actually release (turn to none()) the T we're popping so
|
|
* that we don't keep anyone's refcount up unexpectedly.
|
|
*/
|
|
fn pop_front() -> T {
|
|
let T t = get[T](elts, lo);
|
|
elts.(lo) = option::none[T];
|
|
lo = (lo + 1u) % vec::len[cell[T]](elts);
|
|
nelts -= 1u;
|
|
ret t;
|
|
}
|
|
fn pop_back() -> T {
|
|
if (hi == 0u) {
|
|
hi = vec::len[cell[T]](elts) - 1u;
|
|
} else { hi -= 1u; }
|
|
let T t = get[T](elts, hi);
|
|
elts.(hi) = option::none[T];
|
|
nelts -= 1u;
|
|
ret t;
|
|
}
|
|
fn peek_front() -> T { ret get[T](elts, lo); }
|
|
fn peek_back() -> T { ret get[T](elts, hi - 1u); }
|
|
fn get(int i) -> T {
|
|
let uint idx = (lo + (i as uint)) % vec::len[cell[T]](elts);
|
|
ret get[T](elts, idx);
|
|
}
|
|
}
|
|
let vec[mutable cell[T]] v =
|
|
vec::init_elt_mut(option::none, initial_capacity);
|
|
ret deque[T](0u, 0u, 0u, v);
|
|
}
|
|
// 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 $RBUILD 2>&1 | sed -e 's/\\/x\\//x:\\//g'";
|
|
// End:
|