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|
use "alloc.use"
use "die.use"
use "extremum.use"
use "option.use"
use "types.use"
pkg std =
type htab(@k, @v) = struct
hash : (k : @k -> uint32)
eq : (a : @k, b : @k -> bool)
nelt : size
keys : @k[:]
vals : @v[:]
hashes : uint32[:]
dead : bool[:]
;;
generic mkht : (h : (k : @k -> uint32), eq : (a : @k, b : @k -> bool) -> htab(@k, @v)#)
generic htfree : (ht : htab(@k, @v)# -> void)
generic htput : (ht : htab(@k, @v)#, k : @k, v : @v -> void)
generic htdel : (ht : htab(@k, @v)#, k : @k -> void)
generic htget : (ht : htab(@k, @v)#, k : @k -> option(@v))
generic htgetv : (ht : htab(@k, @v)#, k : @k, fallback : @v-> @v)
generic hthas : (ht : htab(@k, @v)#, k : @k -> bool)
generic htkeys : (ht : htab(@k, @v)# -> @k[:])
;;
const Initsz = 32
generic hash = {ht, k
var h
h = ht.hash(k)
if h == 0
-> 1
else
-> h
;;
}
generic resize = {ht
var oldk
var oldv
var oldh
var oldd
var sz
var i
oldk = ht.keys
oldv = ht.vals
oldh = ht.hashes
oldd = ht.dead
sz = 2*max(ht.keys.len, 1)
ht.keys = slalloc(sz)
ht.vals = slalloc(sz)
ht.hashes = slzalloc(sz)
ht.dead = slzalloc(sz)
ht.nelt = 0
for i = 0; i < oldk.len; i++
if oldh[i] != 0 && !oldd[i]
htput(ht, oldk[i], oldv[i])
;;
;;
slfree(oldk)
slfree(oldv)
slfree(oldh)
slfree(oldd)
}
generic idx = {ht, k
var i, di
var h
di = 0
h = hash(ht, k)
i = h & (ht.keys.len - 1)
while true
while ht.hashes[i] != 0 && !ht.dead[i] && ht.hashes[i] != h
di++
i = (h + di) & (ht.keys.len - 1)
;;
if ht.hashes[i] == 0 || ht.dead[i]
-> `None
;;
if ht.eq(ht.keys[i], k)
break
else
di++
i = (h + di) & (ht.keys.len - 1)
;;
;;
-> `Some i
}
generic mkht = {h, eq
var ht
ht = alloc()
ht.hash = h
ht.eq = eq
ht.nelt = 0
ht.keys = slalloc(Initsz)
ht.vals = slalloc(Initsz)
ht.hashes = slzalloc(Initsz)
ht.dead = slzalloc(Initsz)
-> ht
}
generic htfree = {ht
slfree(ht.keys)
slfree(ht.vals)
slfree(ht.hashes)
slfree(ht.dead)
free(ht)
}
generic htput = {ht, k, v
var i, di
var h
var neltincr
di = 0
h = hash(ht, k)
i = h & (ht.keys.len - 1)
neltincr = 1
while ht.hashes[i] != 0 && !ht.dead[i]
/*
second insertion just overwrites first.
nb: comparing keys for dead values is bad.
*/
if ht.hashes[i] == h
if ht.dead[i]
break
/* replacing a key shouldn't grow the element count */
elif ht.eq(ht.keys[i], k)
neltincr = 0
break
;;
;;
di++
i = (h + di) & (ht.keys.len - 1)
;;
ht.nelt += neltincr
ht.hashes[i] = h
ht.keys[i] = k
ht.vals[i] = v
ht.dead[i] = false
if ht.keys.len < ht.nelt * 2
resize(ht)
;;
}
generic htdel = {ht, k
match idx(ht, k)
| `Some i:
ht.dead[i] = true
ht.nelt--
/* remove tombstones if we shrink enough */
if ht.keys.len > ht.nelt * 4
resize(ht)
;;
| _:
/* do nothing */
;;
}
generic htget = {ht, k
match idx(ht, k)
| `Some i: -> `Some ht.vals[i]
| `None: -> `None
;;
}
generic htgetv = {ht, k, v
match idx(ht, k)
| `Some i: -> ht.vals[i]
| `None: -> v
;;
}
generic hthas = {ht, k
match idx(ht, k)
| `Some i: -> true
| `None: -> false
;;
}
generic htkeys = {ht
var keys
var i
var j
keys = slalloc(ht.nelt)
j = 0
for i = 0; i < ht.keys.len; i++
if ht.hashes[i] != 0 && !ht.dead[i]
keys[j++] = ht.keys[i]
;;
;;
-> keys
}
|
