cajeta.hash.XXHash3 — XXH3-64, the fast general-purpose 64-bit non-cryptographic hash: the default backing algorithm for compiler-synthesized Object.hash(), String.hash(), and @AutoHash. Multi-GB/s throughput, with a small-input path (the typical field-hashing case) of a handful of cycles. Pick over SipHash when the input is not attacker-controlled (~10x faster); the 128-bit hash128 family is the modern replacement for MD5-style fingerprints.

int64 h = XXHash3.hashString("hello");   // process-seeded

XXHash3 x = heap XXHash3();
x.writeInt32(7);
x.writeString("title");
int64 digest = x.finish();

Methods

Signature
One-shot statics (64-bit)
`static int64 hash(int8[] data, int64 len)` ⚑	Hash of `data[0..len)` under the per-process seed
`static int64 hashSeeded(int8[] data, int64 len, int64 seedArg)`	Hash under an explicit `seedArg`, for reproducible digests
`static int64 hashString(String s)` ⚑	Hash of a `String`’s UTF-8 bytes under the per-process seed
`static int64 hashStringSeeded(String s, int64 seedArg)`	Hash of a `String`’s UTF-8 bytes under an explicit `seedArg`
One-shot statics (128-bit)
`static void hash128Into(int8[] data, int64 len, int64 seedArg, int8[] out16)`	128-bit digest under `seedArg`, written as 16 bytes (low64 LE, then high64 LE) into `out16` — zero allocation when the buffer is reused
`static #int8[] hash128(int8[] data, int64 len)`	128-bit digest (per-process seed) as a fresh 16-byte array (low64 LE, then high64 LE)
`static int64 hash128Low(int8[] data, int64 len)`	Low 64 bits of the 128-bit digest
`static int64 hash128High(int8[] data, int64 len)`	High 64 bits of the 128-bit digest
`static #String hash128Hex(int8[] data, int64 len)` ⚑	128-bit digest as the 32-char canonical lowercase hex string (big-endian high64 then low64)
`static #String hash128HexSeeded(int8[] data, int64 len, int64 seedArg)`	128-bit canonical hex digest under an explicit `seedArg`
Streaming
`XXHash3()` ⚑	Construct a streaming hasher seeded with the per-process random seed
`XXHash3(int64 seedArg)`	Construct with an explicit seed — for digests that reproduce across processes
`void update(int8[] data, int64 len)`	Feed `data[0..len)` into the running hash state
`void reset()`	Discard accumulated input and re-seed from the original seed
`int64 finish()`	Finalize and return the 64-bit digest of everything written so far
`Hasher` typed writes
`void writeBoolean(boolean v)`	Feed `v` as one byte: `1` for true, `0` for false
`void writeInt8(int8 v)`	Append the raw byte of `v`
`void writeInt16(int16 v)`	Append the 2 raw bytes of `v`
`void writeInt32(int32 v)`	Append the 4 raw bytes of `v`
`void writeInt64(int64 v)`	Append the 8 raw bytes of `v`
`void writeUInt8(uint8 v)`	Append the raw byte of `v`
`void writeUInt16(uint16 v)`	Append the 2 raw bytes of `v`
`void writeUInt32(uint32 v)`	Append the 4 raw bytes of `v`
`void writeUInt64(uint64 v)`	Append the 8 raw bytes of `v`
`void writeFloat32(float32 v)`	Append the 4 raw bytes of `v`
`void writeFloat64(float64 v)`	Append the 8 raw bytes of `v`
`void writeBytes(int8[] data)`	Feed every byte of `data`
`void writeBytesRange(int8[] data, int64 offset, int64 length)`	Feed `length` bytes of `data` (v1: `offset` is ignored)
`void writeString(String s)`	Feed a `String`’s UTF-8 bytes
`void writeObject(Object obj)`	Mix in `obj.hash()` as 8 bytes
SIMD long-path building blocks (public internals of the pure-cajeta long-input path; `hash()` routes inputs > 240 bytes here)
`static #int8[] buildSecret(int64 seed)`	Build the 192-byte seeded secret (`XXH3_initCustomSecret`)
`static int64 mulFold(int64 a, int64 b)`	64x64 → 128 multiply, folded: `low64(ab) ^ high64(ab)`
`static int64 mix2(int64 a0, int64 a1, int8[] secret, int64 off)`	Mix two accumulator lanes against the secret
`static int64 avalanche(int64 h)`	Final avalanche mix
`static int64 hashLong(int8[] data, int64 len, int64 seed)`	The long-input driver — bit-identical to the native `XXH3_64bits_withSeed` long path
`static void hashLong128Into(int8[] data, int64 len, int64 seed, int8[] out16)`	128-bit long-input driver, writing 16 bytes into `out16`

⚑ = @EntryPoint

XXHash3

Methods

See also