JustAnotherJAPL/src/backend/types/hashmap.nim

164 lines
4.8 KiB
Nim

# Copyright 2021 Mattia Giambirtone & All Contributors
#
# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at
#
# http://www.apache.org/licenses/LICENSE-2.0
#
# Unless required by applicable law or agreed to in writing, software
# distributed under the License is distributed on an "AS IS" BASIS,
# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and
# limitations under the License.
import ../../memory/allocator
import ../../config
import base
import iterable
type
Entry = object
key: ptr Obj
value: ptr Obj
tombstone: bool
HashMap* = object of Iterable
entries: ptr UncheckedArray[ptr Entry]
actual_length: int
proc newHashMap*(): ptr HashMap =
result = allocateObj(HashMap, ObjectType.Dict)
result.actual_length = 0
result.entries = nil
result.capacity = 0
result.length = 0
proc freeHashMap*(self: ptr HashMap) =
discard freeArray(UncheckedArray[ptr Entry], self.entries, self.capacity)
self.length = 0
self.actual_length = 0
self.capacity = 0
self.entries = nil
proc findEntry(self: ptr UncheckedArray[ptr Entry], key: ptr Obj, capacity: int): ptr Entry =
var capacity = uint64(capacity)
var idx = uint64(key.hash()) mod capacity
while true:
result = self[idx]
if system.`==`(result.key, nil):
break
elif result.tombstone:
if result.key == key:
break
elif result.key == key:
break
idx = (idx + 1) mod capacity
proc adjustCapacity(self: ptr HashMap) =
var newCapacity = growCapacity(self.capacity)
var entries = allocate(UncheckedArray[ptr Entry], Entry, newCapacity)
var oldEntry: ptr Entry
var newEntry: ptr Entry
self.length = 0
for x in countup(0, newCapacity - 1):
entries[x] = allocate(Entry, Entry, 1)
entries[x].tombstone = false
entries[x].key = nil
entries[x].value = nil
for x in countup(0, self.capacity - 1):
oldEntry = self.entries[x]
if not system.`==`(oldEntry.key, nil):
newEntry = entries.findEntry(oldEntry.key, newCapacity)
newEntry.key = oldEntry.key
newEntry.value = oldEntry.value
self.length += 1
discard freeArray(UncheckedArray[ptr Entry], self.entries, self.capacity)
self.entries = entries
self.capacity = newCapacity
proc setEntry(self: ptr HashMap, key: ptr Obj, value: ptr Obj): bool =
if float64(self.length + 1) >= float64(self.capacity) * MAP_LOAD_FACTOR:
self.adjustCapacity()
var entry = findEntry(self.entries, key, self.capacity)
result = system.`==`(entry.key, nil)
if result:
self.actual_length += 1
self.length += 1
entry.key = key
entry.value = value
entry.tombstone = false
proc `[]`*(self: ptr HashMap, key: ptr Obj): ptr Obj =
var entry = findEntry(self.entries, key, self.capacity)
if system.`==`(entry.key, nil) or entry.tombstone:
raise newException(KeyError, "Key not found: " & $key)
result = entry.value
proc `[]=`*(self: ptr HashMap, key: ptr Obj, value: ptr Obj) =
discard self.setEntry(key, value)
proc len*(self: ptr HashMap): int =
result = self.actual_length
proc del*(self: ptr HashMap, key: ptr Obj) =
if self.len() == 0:
raise newException(KeyError, "delete from empty hashmap")
var entry = findEntry(self.entries, key, self.capacity)
if not system.`==`(entry.key, nil):
self.actual_length -= 1
entry.tombstone = true
else:
raise newException(KeyError, "Key not found: " & $key)
proc contains*(self: ptr HashMap, key: ptr Obj): bool =
let entry = findEntry(self.entries, key, self.capacity)
if not system.`==`(entry.key, nil) and not entry.tombstone:
result = true
else:
result = false
iterator keys*(self: ptr HashMap): ptr Obj =
var entry: ptr Entry
for i in countup(0, self.capacity - 1):
entry = self.entries[i]
if not system.`==`(entry.key, nil) and not entry.tombstone:
yield entry.key
iterator values*(self: ptr HashMap): ptr Obj =
for key in self.keys():
yield self[key]
iterator pairs*(self: ptr HashMap): tuple[key: ptr Obj, val: ptr Obj] =
for key in self.keys():
yield (key: key, val: self[key])
iterator items*(self: ptr HashMap): ptr Obj =
for k in self.keys():
yield k
proc `$`*(self: ptr HashMap): string =
var i = 0
result &= "{"
for key, value in self.pairs():
result &= $key & ": " & $value
if i < self.len() - 1:
result &= ", "
i += 1
result &= "}"