ArrayMap.py

.vscode/settings.json

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+{
+    "java.compile.nullAnalysis.mode": "automatic"
+}

python/selfie-lib/selfie_lib/ArrayMap.py

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+from collections.abc import Set, Sequence, Iterator, Mapping
+from typing import List
+from functools import cmp_to_key
+
+class ListBackedSet(Set[T], Sequence[T]):
+    def __getitem__(self, index: int) -> T:
+        # This method should be implemented by the subclass.
+        raise NotImplementedError
+
+    def __len__(self) -> int:
+        # This should also be implemented by the subclass to return the number of items.
+        raise NotImplementedError
+
+    def __iter__(self) -> Iterator[T]:
+        return self.ListBackedSetIterator(self)
+
+    class ListBackedSetIterator(Iterator[T]):
+        def __init__(self, list_backed_set: 'ListBackedSet[T]'):
+            self.list_backed_set = list_backed_set
+            self.index = 0
+
+        def __next__(self) -> T:
+            if self.index < len(self.list_backed_set):
+                result = self.list_backed_set[self.index]
+                self.index += 1
+                return result
+            else:
+                raise StopIteration
+
+    def __contains__(self, item: object) -> bool:
+        # Efficient implementation of __contains__ should be provided by subclass if needed.
+        for i in self:
+            if i == item:
+                return True
+        return False
+
+class ArraySet(ListBackedSet[K]):
+    def __init__(self, data: list):
+        self.data = data
+        self.sort_data()
+
+    def sort_data(self):
+        if self.data and isinstance(self.data[0], str):
+            self.data.sort(key=cmp_to_key(self.string_slash_first_comparator))
+        else:
+            self.data.sort()
+
+    def string_slash_first_comparator(self, a, b):
+        # Define sorting where '/' is considered the lowest key
+        if a == '/':
+            return -1
+        elif b == '/':
+            return 1
+        else:
+            return (a > b) - (a < b)
+
+    def __len__(self):
+        return len(self.data)
+
+    def __getitem__(self, index: int) -> K:
+        return self.data[index]
+
+    def __contains__(self, item: K) -> bool:
+        # Implementing binary search for efficiency
+        left, right = 0, len(self.data) - 1
+        while left <= right:
+            mid = (left + right) // 2
+            if self.data[mid] == item:
+                return True
+            elif self.data[mid] < item:
+                left = mid + 1
+            else:
+                right = mid - 1
+        return False
+
+    def plus_or_this(self, key: K) -> 'ArraySet[K]':
+        # Binary search to find the appropriate index or confirm existence
+        left, right = 0, len(self.data) - 1
+        while left <= right:
+            mid = (left + right) // 2
+            if self.data[mid] == key:
+                return self  # Key already exists
+            elif self.data[mid] < key:
+                left = mid + 1
+            else:
+                right = mid - 1
+
+        # Key does not exist, insert in the sorted position
+        new_data = self.data[:left] + [key] + self.data[left:]
+        return ArraySet(new_data)
+
+class ArrayMap(Mapping[K, V]):
+    def __init__(self, data: list):
+        self.data = data
+
+    @classmethod
+    def empty(cls):
+        return cls([])
+
+    def __getitem__(self, key: K) -> V:
+        index = self._binary_search_key(key)
+        if index >= 0:
+            return self.data[2 * index + 1]
+        raise KeyError(key)
+
+    def __iter__(self):
+        return (self.data[i] for i in range(0, len(self.data), 2))
+
+    def __len__(self) -> int:
+        return len(self.data) // 2
+
+    def _binary_search_key(self, key: K) -> int:
+        low, high = 0, len(self.data) // 2 - 1
+        while low <= high:
+            mid = (low + high) // 2
+            mid_key = self.data[2 * mid]
+            if mid_key < key:
+                low = mid + 1
+            elif mid_key > key:
+                high = mid - 1
+            else:
+                return mid
+        return -(low + 1)
+
+    def plus(self, key: K, value: V) -> 'ArrayMap[K, V]':
+        index = self._binary_search_key(key)
+        if index >= 0:
+            raise ValueError("Key already exists")
+        else:
+            insert_at = -(index + 1)
+            new_data = self.data[:]
+            new_data[insert_at * 2:insert_at * 2] = [key, value]
+            return ArrayMap(new_data)
+
+    def minus_sorted_indices(self, indicesToRemove: list[int]) -> 'ArrayMap[K, V]':
+        if not indicesToRemove:
+            return self
+        newData = []
+        for i in range(0, len(self.data), 2):
+            if i // 2 not in indicesToRemove:
+                newData.extend(self.data[i:i + 2])
+        return ArrayMap(newData)

python/selfie-lib/tests/ArrayMap_test.py

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+import unittest
+from selfie_lib.ArrayMap import ArrayMap
+
+class ArrayMapTest(unittest.TestCase):
+    def assertEmpty(self, map):
+        self.assertEqual(len(map), 0)
+        self.assertEqual(list(map.keys()), [])
+        self.assertEqual(list(map.values()), [])
+        self.assertEqual(list(map.items()), [])
+        with self.assertRaises(KeyError):
+            _ = map["key"]
+        self.assertEqual(map, {})
+        self.assertEqual(map, ArrayMap.empty())
+
+    def assertSingle(self, map, key, value):
+        self.assertEqual(len(map), 1)
+        self.assertEqual(set(map.keys()), {key})
+        self.assertEqual(list(map.values()), [value])
+        self.assertEqual(set(map.items()), {(key, value)})
+        self.assertEqual(map[key], value)
+        with self.assertRaises(KeyError):
+            _ = map[key + "blah"]
+        self.assertEqual(map, {key: value})
+        self.assertEqual(map, ArrayMap.empty().plus(key, value))
+
+    def assertDouble(self, map, key1, value1, key2, value2):
+        self.assertEqual(len(map), 2)
+        self.assertEqual(set(map.keys()), {key1, key2})
+        self.assertEqual(list(map.values()), [value1, value2])
+        self.assertEqual(set(map.items()), {(key1, value1), (key2, value2)})
+        self.assertEqual(map[key1], value1)
+        self.assertEqual(map[key2], value2)
+        with self.assertRaises(KeyError):
+            _ = map[key1 + "blah"]
+        self.assertEqual(map, {key1: value1, key2: value2})
+        self.assertEqual(map, {key2: value2, key1: value1})
+        self.assertEqual(map, ArrayMap.empty().plus(key1, value1).plus(key2, value2))
+        self.assertEqual(map, ArrayMap.empty().plus(key2, value2).plus(key1, value1))
+
+    def assertTriple(self, map, key1, value1, key2, value2, key3, value3):
+        self.assertEqual(len(map), 3)
+        self.assertEqual(set(map.keys()), {key1, key2, key3})
+        self.assertEqual(list(map.values()), [value1, value2, value3])
+        self.assertEqual(set(map.items()), {(key1, value1), (key2, value2), (key3, value3)})
+        self.assertEqual(map[key1], value1)
+        self.assertEqual(map[key2], value2)
+        self.assertEqual(map[key3], value3)
+        with self.assertRaises(KeyError):
+            _ = map[key1 + "blah"]
+        self.assertEqual(map, {key1: value1, key2: value2, key3: value3})
+        self.assertEqual(map, ArrayMap.empty().plus(key1, value1).plus(key2, value2).plus(key3, value3))
+
+    def test_empty(self):
+        self.assertEmpty(ArrayMap.empty())
+
+    def test_single(self):
+        empty = ArrayMap.empty()
+        single = empty.plus("one", "1")
+        self.assertEmpty(empty)
+        self.assertSingle(single, "one", "1")
+
+    def test_double(self):
+        empty = ArrayMap.empty()
+        single = empty.plus("one", "1")
+        double = single.plus("two", "2")
+        self.assertEmpty(empty)
+        self.assertSingle(single, "one", "1")
+        self.assertDouble(double, "one", "1", "two", "2")
+        self.assertDouble(single.plus("a", "sorted"), "a", "sorted", "one", "1")
+
+        with self.assertRaises(ValueError) as context:
+            single.plus("one", "2")
+        self.assertEqual(str(context.exception), "Key already exists")
+
+    def test_triple(self):
+        triple = ArrayMap.empty().plus("1", "one").plus("2", "two").plus("3", "three")
+        self.assertTriple(triple, "1", "one", "2", "two", "3", "three")
+
+    def test_multi(self):
+        self.test_triple() 
+        triple = ArrayMap.empty().plus("2", "two").plus("3", "three").plus("1", "one")
+        self.assertTriple(triple, "1", "one", "2", "two", "3", "three")
+        triple = ArrayMap.empty().plus("3", "three").plus("1", "one").plus("2", "two")
+        self.assertTriple(triple, "1", "one", "2", "two", "3", "three")
+
+if __name__ == '__main__':
+    unittest.main()