1	import Base
2	import mylsm-lsm-store@0.3.2.0/src/hub_sha/sha256.bend as ProvenSha
3	import bend-codec-lib@0.2.0.0/utf8.bend as Utf8Lib
4	import bend-codec-lib@0.2.0.0/bytes.bend as ByteLib
5	
6	# SHA-256 hex of UTF-8 text. ProvenSha/Utf8 cores are trusted upstream
7	# (FIPS 180-4 machine-checked; closed roundtrips proved); this module owns
8	# only the byte-list plumbing between them, covered by the differential
9	# check vs Python hashlib at the 55/56/64-byte padding boundaries.
10	# Unwraps the byte box into the word list the hash core consumes.
11	def bytes_data(byte_box: ByteLib.Bytes) -> List<&2, U32>:
12	  match byte_box:
13	    case ByteLib.Bytes{raw_data}:
14	      raw_data
15	
16	# Hashes valid encodings; unencodable input yields a fixed sentinel string.
17	def digest_from_encode_result(encode_result: Result<&2, &2, Utf8Lib.Utf8.Error, ByteLib.Bytes>) -> String:
18	  match encode_result:
19	    case Fail{encode_error}:
20	      "INVALID_UTF8_INPUT"
21	    case Done{byte_box}:
22	      ProvenSha.hex(ProvenSha.sha256(bytes_data(byte_box)))
23	
24	# "INVALID_UTF8_INPUT" on unencodable text; never fails on valid input.
25	def compute_sha256_hex(input_text: String) -> String:
26	  digest_from_encode_result(Utf8Lib.Utf8.encode(input_text))