From dfda6924c0d531512d52b78e0c53556d0b350f51 Mon Sep 17 00:00:00 2001 From: Andrey Rudakov Date: Tue, 22 Sep 2026 21:59:55 +0300 Subject: [PATCH] Solve Task 1 --- src/part1/constants.py | 21 +++++++++++++-------- src/part1/snowflake.py | 43 ++++++++++++++++++++++++++++++------------ 2 files changed, 44 insertions(+), 20 deletions(-) diff --git a/src/part1/constants.py b/src/part1/constants.py index 9abfbba2..fec8d028 100644 --- a/src/part1/constants.py +++ b/src/part1/constants.py @@ -19,20 +19,25 @@ # Все константы, зависящие от ёмкостей *_BITS, должны вычисляться из них. # Twitter's original Snowflake epoch: 2010-11-04 01:42:54.657 UTC. -EPOCH_MS_DEFAULT: Final[int] = 0 +EPOCH_MS_DEFAULT: Final[int] = 1288834974657 # Node identifier used when the caller does not supply one. -NODE_ID_DEFAULT: Final[int] = 0 +NODE_ID_DEFAULT: Final[int] = 1 # Width of each field, in bits. -TIMESTAMP_BITS: Final[int] = 0 -NODE_ID_BITS: Final[int] = 0 -SEQUENCE_ID_BITS: Final[int] = 0 +TIMESTAMP_BITS: Final[int] = 41 +NODE_ID_BITS: Final[int] = 10 +SEQUENCE_ID_BITS: Final[int] = 12 # Largest value each field can hold. -TIMESTAMP_MS_MAX: Final[int] = 0 -NODE_ID_MAX: Final[int] = 0 -SEQUENCE_ID_MAX: Final[int] = 0 +TIMESTAMP_MS_MAX: Final[int] = (1 << TIMESTAMP_BITS) - 1 +NODE_ID_MAX: Final[int] = (1 << NODE_ID_BITS) - 1 +SEQUENCE_ID_MAX: Final[int] = (1 << SEQUENCE_ID_BITS) - 1 # Здесь можно добавить собственные вспомогательные константы # (например, сдвиги полей при сборке идентификатора). + +# Shift amounts +SEQUENCE_ID_SHIFT = 0 +NODE_ID_SHIFT = SEQUENCE_ID_BITS +TIMESTAMP_SHIFT = SEQUENCE_ID_BITS + NODE_ID_BITS diff --git a/src/part1/snowflake.py b/src/part1/snowflake.py index d3abf050..979a38a0 100644 --- a/src/part1/snowflake.py +++ b/src/part1/snowflake.py @@ -13,14 +13,16 @@ :func:`decode_node_id` and :func:`decode_sequence_id`. """ -import time # noqa: F401 +import time -from .constants import ( # noqa: F401 +from .constants import ( EPOCH_MS_DEFAULT, NODE_ID_DEFAULT, NODE_ID_MAX, + NODE_ID_SHIFT, SEQUENCE_ID_MAX, TIMESTAMP_MS_MAX, + TIMESTAMP_SHIFT, ) @@ -34,8 +36,7 @@ def read_current_millis(epoch_ms: int) -> int: The count of whole milliseconds between ``epoch_ms`` and now. May be negative if ``epoch_ms`` lies in the future. """ - # TODO: реализуйте функцию - return 0 + return int(time.time() * 1000) - epoch_ms def decode_timestamp_ms(snowflake_id: int, epoch_ms: int = EPOCH_MS_DEFAULT) -> int: @@ -50,8 +51,8 @@ def decode_timestamp_ms(snowflake_id: int, epoch_ms: int = EPOCH_MS_DEFAULT) -> The absolute Unix time in milliseconds at which the identifier was generated. """ - # TODO: реализуйте функцию - return 0 + stored_ms = (snowflake_id >> TIMESTAMP_SHIFT) & TIMESTAMP_MS_MAX + return stored_ms + epoch_ms def decode_node_id(snowflake_id: int) -> int: @@ -64,8 +65,7 @@ def decode_node_id(snowflake_id: int) -> int: The node identifier packed into ``snowflake_id``, in the range ``[0, NODE_ID_MAX]``. """ - # TODO: реализуйте функцию - return 0 + return (snowflake_id >> NODE_ID_SHIFT) & NODE_ID_MAX def decode_sequence_id(snowflake_id: int) -> int: @@ -78,8 +78,7 @@ def decode_sequence_id(snowflake_id: int) -> int: The per-millisecond sequence counter packed into ``snowflake_id``, in the range ``[0, SEQUENCE_ID_MAX]``. """ - # TODO: реализуйте функцию - return 0 + return (snowflake_id >> 0) & SEQUENCE_ID_MAX def generate_snowflake_id( @@ -110,5 +109,25 @@ def generate_snowflake_id( timestamp field (roughly 69 years after ``epoch_ms``). In each of those cases an explanatory message is printed to stdout first. """ - # TODO: реализуйте функцию - return 0 + if not (0 <= node_id <= NODE_ID_MAX): + print(f"node_id must be in [0, {NODE_ID_MAX}], got {node_id}") + return None + + if not (0 <= sequence_id <= SEQUENCE_ID_MAX): + print(f"sequence_id must be in [0, {SEQUENCE_ID_MAX}], got {sequence_id}") + return None + + elapsed_ms = read_current_millis(epoch_ms) + if elapsed_ms > TIMESTAMP_MS_MAX: + print( + f"timestamp overflows: elapsed {elapsed_ms} ms exceeds \n\ + TIMESTAMP_MS_MAX ({TIMESTAMP_MS_MAX})" + ) + return None + + snowflake_id = ( + (elapsed_ms << TIMESTAMP_SHIFT) + | (node_id << NODE_ID_SHIFT) + | (sequence_id << 0) + ) + return snowflake_id