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/*
package tuplehash implements the TupleHash and TupleHashXOF algorithms.
See:
- https://nvlpubs.nist.gov/nistpubs/specialpublications/nist.sp.800-185.pdf
*/
package tuplehash
import "../_sha3"
// Context is a TupleHash or TupleHashXOF instance.
Context :: distinct _sha3.Context
// init_128 initializes a Context for TupleHash128 or TupleHashXOF128.
init_128 :: proc(ctx: ^Context, domain_sep: []byte) {
_sha3.init_cshake(transmute(^_sha3.Context)(ctx), N_TUPLEHASH, domain_sep, 128)
}
// init_256 initializes a Context for TupleHash256 or TupleHashXOF256.
init_256 :: proc(ctx: ^Context, domain_sep: []byte) {
_sha3.init_cshake(transmute(^_sha3.Context)(ctx), N_TUPLEHASH, domain_sep, 256)
}
// write_element writes a tuple element into the TupleHash or TupleHashXOF
// instance. This MUST not be called after any reads have been done, and
// any attempts to do so will panic.
write_element :: proc(ctx: ^Context, data: []byte) {
_, _ = _sha3.encode_string(transmute(^_sha3.Context)(ctx), data)
}
// final finalizes the Context, writes the digest to hash, and calls
// reset on the Context.
//
// Iff finalize_clone is set, final will work on a copy of the Context,
// which is useful for for calculating rolling digests.
final :: proc(ctx: ^Context, hash: []byte, finalize_clone: bool = false) {
_sha3.final_cshake(transmute(^_sha3.Context)(ctx), hash, finalize_clone)
}
// read reads output from the TupleHashXOF instance. There is no practical
// upper limit to the amount of data that can be read from TupleHashXOF.
// After read has been called one or more times, further calls to
// write_element will panic.
read :: proc(ctx: ^Context, dst: []byte) {
ctx_ := transmute(^_sha3.Context)(ctx)
if !ctx.is_finalized {
_sha3.encode_byte_len(ctx_, 0, false) // right_encode
_sha3.shake_xof(ctx_)
}
_sha3.shake_out(ctx_, dst)
}
// clone clones the Context other into ctx.
clone :: proc(ctx, other: ^Context) {
_sha3.clone(transmute(^_sha3.Context)(ctx), transmute(^_sha3.Context)(other))
}
// reset sanitizes the Context. The Context must be re-initialized to
// be used again.
reset :: proc(ctx: ^Context) {
_sha3.reset(transmute(^_sha3.Context)(ctx))
}
@(private)
N_TUPLEHASH := []byte{'T', 'u', 'p', 'l', 'e', 'H', 'a', 's', 'h'}
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