`iceberg.util`

The three things a writer needs from outside itself: the wall clock, a random 64-bit number, and a UUID.

Mojo's std.time only exposes monotonic counters, so last-updated-ms and a snapshot's timestamp-ms come from clock_gettime(CLOCK_REALTIME) directly. Snapshot ids are "a random long" in the spec's words, and every file this library writes is named with a version 4 UUID. Both are read from the operating system (/dev/urandom), not drawn from std.random: that generator starts from the same state in every process unless something seeds it, so two processes committing to one table at once would draw the same snapshot ids and file names and overwrite each other's manifest lists.

Functions

`now_ms`

def now_ms() -> Int64

Milliseconds since the Unix epoch.

`random_long`

def random_long() -> Int64

A random signed 64-bit value, for a snapshot id.

The spec says only "a unique long"; every implementation uses a random one, and the top bit is cleared so the id prints without a sign — which is what Java's SnapshotIdGeneratorUtil does too.

`uuid4`

def uuid4() -> String

A version 4 UUID in the canonical 8-4-4-4-12 form.

`seed_random`

def seed_random()

Seeds std.random from the clock. Ids and UUIDs no longer come from it, so this is only for callers' own use of std.random.

`zero_pad`

def zero_pad(v: Int, width: Int) -> String

5, 5 -> 00005, the way Java names metadata files.