2025-12-25 upload

venv/Lib/site-packages/mitmproxy/utils/sliding_window.py

@@ -0,0 +1,32 @@
+import itertools
+from collections.abc import Iterable
+from collections.abc import Iterator
+from typing import TypeVar
+
+T = TypeVar("T")
+
+
+def window(
+    iterator: Iterable[T], behind: int = 0, ahead: int = 0
+) -> Iterator[tuple[T | None, ...]]:
+    """
+    Sliding window for an iterator.
+
+    Example:
+        >>> for prev, i, nxt in window(range(10), 1, 1):
+        >>>     print(prev, i, nxt)
+
+        None 0 1
+        0 1 2
+        1 2 3
+        2 3 None
+    """
+    # TODO: move into utils
+    iters: list[Iterator[T | None]] = list(itertools.tee(iterator, behind + 1 + ahead))
+    for i in range(behind):
+        iters[i] = itertools.chain((behind - i) * [None], iters[i])
+    for i in range(ahead):
+        iters[-1 - i] = itertools.islice(
+            itertools.chain(iters[-1 - i], (ahead - i) * [None]), (ahead - i), None
+        )
+    return zip(*iters)