Press n or j to go to the next uncovered block, b, p or k for the previous block.
| 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 | 33x 33x 33x 33x 33x 33x 24x 24x 24x 24x 24x 24x 24x 24x 3048x | import { Binary } from 'cafe-utility'
import { BeeArgumentError } from '../utils/error'
import { Reference, Span } from '../utils/typed-bytes'
const MAX_CHUNK_PAYLOAD_SIZE = 4096
const SEGMENT_SIZE = 32
/**
* Calculate a Binary Merkle Tree hash for a chunk
*
* The BMT chunk address is the hash of the 8 byte span and the root
* hash of a binary Merkle tree (BMT) built on the 32-byte segments
* of the underlying data.
*
* If the chunk content is less than 4k, the hash is calculated as
* if the chunk was padded with all zeros up to 4096 bytes.
*
* @param chunkContent Chunk data including span and payload as well
*
* @returns the keccak256 hash in a byte array
*/
export function calculateChunkAddress(chunkContent: Uint8Array): Reference {
const span = chunkContent.slice(0, Span.LENGTH)
const payload = chunkContent.slice(Span.LENGTH)
const rootHash = calculateBmtRootHash(payload)
const chunkHash = Binary.keccak256(Binary.concatBytes(span, rootHash))
return new Reference(chunkHash)
}
function calculateBmtRootHash(payload: Uint8Array): Uint8Array {
Iif (payload.length > MAX_CHUNK_PAYLOAD_SIZE) {
throw new BeeArgumentError(
`payload size ${payload.length} exceeds maximum chunk payload size ${MAX_CHUNK_PAYLOAD_SIZE}`,
payload,
)
}
const input = new Uint8Array(MAX_CHUNK_PAYLOAD_SIZE)
input.set(payload)
return Binary.log2Reduce(Binary.partition(input, SEGMENT_SIZE), (a, b) => Binary.keccak256(Binary.concatBytes(a, b)))
}
|