nim-libp2p/libp2p/multihash.nim

524 lines
23 KiB
Nim

## Nim-Libp2p
## Copyright (c) 2018 Status Research & Development GmbH
## Licensed under either of
## * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE))
## * MIT license ([LICENSE-MIT](LICENSE-MIT))
## at your option.
## This file may not be copied, modified, or distributed except according to
## those terms.
## This module implements MultiHash.
## Supported hashes are:
## 1. IDENTITY
## 2. SHA2-256/SHA2-512
## 3. DBL-SHA2-256
## 4. SHA3/KECCAK
## 5. SHAKE-128/SHAKE-256
## 6. BLAKE2s/BLAKE2s
##
## Hashes which are not yet supported
## 1. SHA1
## 2. SKEIN
## 3. MURMUR
import tables
import nimcrypto/[sha2, keccak, blake2, hash, utils]
import varint, vbuffer, base58
const
MaxHashSize* = 128
type
MHashCoderProc* = proc(data: openarray[byte],
output: var openarray[byte]) {.nimcall, gcsafe.}
MHash* = object
name*: string
code*: int
size*: int
coder*: MHashCoderProc
MultiHash* = object
data*: VBuffer
code*: int
size*: int
dpos*: int
MultiHashError* = object of Exception
proc identhash(data: openarray[byte], output: var openarray[byte]) =
if len(output) > 0:
var length = if len(data) > len(output): len(output)
else: len(data)
copyMem(addr output[0], unsafeAddr data[0], length)
proc dblsha2_256hash(data: openarray[byte], output: var openarray[byte]) =
if len(output) > 0:
var digest1 = sha256.digest(data)
var digest2 = sha256.digest(digest1.data)
var length = if sha256.sizeDigest > len(output): len(output)
else: sha256.sizeDigest
copyMem(addr output[0], addr digest2.data[0], length)
proc blake2Bhash(data: openarray[byte], output: var openarray[byte]) =
if len(output) > 0:
var digest = blake2_512.digest(data)
var length = if blake2_512.sizeDigest > len(output): len(output)
else: blake2_512.sizeDigest
copyMem(addr output[0], addr digest.data[0], length)
proc blake2Shash(data: openarray[byte], output: var openarray[byte]) =
if len(output) > 0:
var digest = blake2_256.digest(data)
var length = if blake2_256.sizeDigest > len(output): len(output)
else: blake2_256.sizeDigest
copyMem(addr output[0], addr digest.data[0], length)
proc sha2_256hash(data: openarray[byte], output: var openarray[byte]) =
if len(output) > 0:
var digest = sha256.digest(data)
var length = if sha256.sizeDigest > len(output): len(output)
else: sha256.sizeDigest
copyMem(addr output[0], addr digest.data[0], length)
proc sha2_512hash(data: openarray[byte], output: var openarray[byte]) =
if len(output) > 0:
var digest = sha512.digest(data)
var length = if sha512.sizeDigest > len(output): len(output)
else: sha512.sizeDigest
copyMem(addr output[0], addr digest.data[0], length)
proc sha3_224hash(data: openarray[byte], output: var openarray[byte]) =
if len(output) > 0:
var digest = sha3_224.digest(data)
var length = if sha3_224.sizeDigest > len(output): len(output)
else: sha3_224.sizeDigest
copyMem(addr output[0], addr digest.data[0], length)
proc sha3_256hash(data: openarray[byte], output: var openarray[byte]) =
if len(output) > 0:
var digest = sha3_256.digest(data)
var length = if sha3_256.sizeDigest > len(output): len(output)
else: sha3_256.sizeDigest
copyMem(addr output[0], addr digest.data[0], length)
proc sha3_384hash(data: openarray[byte], output: var openarray[byte]) =
if len(output) > 0:
var digest = sha3_384.digest(data)
var length = if sha3_384.sizeDigest > len(output): len(output)
else: sha3_384.sizeDigest
copyMem(addr output[0], addr digest.data[0], length)
proc sha3_512hash(data: openarray[byte], output: var openarray[byte]) =
if len(output) > 0:
var digest = sha3_512.digest(data)
var length = if sha3_512.sizeDigest > len(output): len(output)
else: sha3_512.sizeDigest
copyMem(addr output[0], addr digest.data[0], length)
proc keccak_224hash(data: openarray[byte], output: var openarray[byte]) =
if len(output) > 0:
var digest = keccak224.digest(data)
var length = if keccak224.sizeDigest > len(output): len(output)
else: keccak224.sizeDigest
copyMem(addr output[0], addr digest.data[0], length)
proc keccak_256hash(data: openarray[byte], output: var openarray[byte]) =
if len(output) > 0:
var digest = keccak256.digest(data)
var length = if keccak256.sizeDigest > len(output): len(output)
else: keccak256.sizeDigest
copyMem(addr output[0], addr digest.data[0], length)
proc keccak_384hash(data: openarray[byte], output: var openarray[byte]) =
if len(output) > 0:
var digest = keccak384.digest(data)
var length = if keccak384.sizeDigest > len(output): len(output)
else: keccak384.sizeDigest
copyMem(addr output[0], addr digest.data[0], length)
proc keccak_512hash(data: openarray[byte], output: var openarray[byte]) =
if len(output) > 0:
var digest = keccak512.digest(data)
var length = if keccak512.sizeDigest > len(output): len(output)
else: keccak512.sizeDigest
copyMem(addr output[0], addr digest.data[0], length)
proc shake_128hash(data: openarray[byte], output: var openarray[byte]) =
var sctx: shake128
if len(output) > 0:
sctx.init()
sctx.update(cast[ptr uint8](unsafeAddr data[0]), uint(len(data)))
sctx.xof()
discard sctx.output(addr output[0], uint(len(output)))
sctx.clear()
proc shake_256hash(data: openarray[byte], output: var openarray[byte]) =
var sctx: shake256
if len(output) > 0:
sctx.init()
sctx.update(cast[ptr uint8](unsafeAddr data[0]), uint(len(data)))
sctx.xof()
discard sctx.output(addr output[0], uint(len(output)))
sctx.clear()
const
HashesList = [
MHash(name: "identity", code: 0x00, size: 0, coder: identhash),
MHash(name: "dbl-sha2-256", code: 0x56, size: sha256.sizeDigest,
coder: dblsha2_256hash
),
MHash(name: "sha2-256", code: 0x12, size: sha256.sizeDigest,
coder: sha2_256hash
),
MHash(name: "sha2-512", code: 0x13, size: sha512.sizeDigest,
coder: sha2_512hash
),
MHash(name: "sha3-224", code: 0x17, size: sha3_224.sizeDigest,
coder: sha3_224hash
),
MHash(name: "sha3-256", code: 0x16, size: sha3_256.sizeDigest,
coder: sha3_256hash
),
MHash(name: "sha3-384", code: 0x15, size: sha3_384.sizeDigest,
coder: sha3_384hash
),
MHash(name: "sha3-512", code: 0x14, size: sha3_512.sizeDigest,
coder: sha3_512hash
),
MHash(name: "shake-128", code: 0x18, size: 32, coder: shake_128hash),
MHash(name: "shake-256", code: 0x19, size: 64, coder: shake_256hash),
MHash(name: "keccak-224", code: 0x1A, size: keccak_224.sizeDigest,
coder: keccak_224hash
),
MHash(name: "keccak-256", code: 0x1B, size: keccak_256.sizeDigest,
coder: keccak_256hash
),
MHash(name: "keccak-384", code: 0x1C, size: keccak_384.sizeDigest,
coder: keccak_384hash
),
MHash(name: "keccak-512", code: 0x1D, size: keccak_512.sizeDigest,
coder: keccak_512hash
),
MHash(name: "blake2b-8", code: 0xB201, size: 1, coder: blake2Bhash),
MHash(name: "blake2b-16", code: 0xB202, size: 2, coder: blake2Bhash),
MHash(name: "blake2b-24", code: 0xB203, size: 3, coder: blake2Bhash),
MHash(name: "blake2b-32", code: 0xB204, size: 4, coder: blake2Bhash),
MHash(name: "blake2b-40", code: 0xB205, size: 5, coder: blake2Bhash),
MHash(name: "blake2b-48", code: 0xB206, size: 6, coder: blake2Bhash),
MHash(name: "blake2b-56", code: 0xB207, size: 7, coder: blake2Bhash),
MHash(name: "blake2b-64", code: 0xB208, size: 8, coder: blake2Bhash),
MHash(name: "blake2b-72", code: 0xB209, size: 9, coder: blake2Bhash),
MHash(name: "blake2b-80", code: 0xB20A, size: 10, coder: blake2Bhash),
MHash(name: "blake2b-88", code: 0xB20B, size: 11, coder: blake2Bhash),
MHash(name: "blake2b-96", code: 0xB20C, size: 12, coder: blake2Bhash),
MHash(name: "blake2b-104", code: 0xB20D, size: 13, coder: blake2Bhash),
MHash(name: "blake2b-112", code: 0xB20E, size: 14, coder: blake2Bhash),
MHash(name: "blake2b-120", code: 0xB20F, size: 15, coder: blake2Bhash),
MHash(name: "blake2b-128", code: 0xB210, size: 16, coder: blake2Bhash),
MHash(name: "blake2b-136", code: 0xB211, size: 17, coder: blake2Bhash),
MHash(name: "blake2b-144", code: 0xB212, size: 18, coder: blake2Bhash),
MHash(name: "blake2b-152", code: 0xB213, size: 19, coder: blake2Bhash),
MHash(name: "blake2b-160", code: 0xB214, size: 20, coder: blake2Bhash),
MHash(name: "blake2b-168", code: 0xB215, size: 21, coder: blake2Bhash),
MHash(name: "blake2b-176", code: 0xB216, size: 22, coder: blake2Bhash),
MHash(name: "blake2b-184", code: 0xB217, size: 23, coder: blake2Bhash),
MHash(name: "blake2b-192", code: 0xB218, size: 24, coder: blake2Bhash),
MHash(name: "blake2b-200", code: 0xB219, size: 25, coder: blake2Bhash),
MHash(name: "blake2b-208", code: 0xB21A, size: 26, coder: blake2Bhash),
MHash(name: "blake2b-216", code: 0xB21B, size: 27, coder: blake2Bhash),
MHash(name: "blake2b-224", code: 0xB21C, size: 28, coder: blake2Bhash),
MHash(name: "blake2b-232", code: 0xB21D, size: 29, coder: blake2Bhash),
MHash(name: "blake2b-240", code: 0xB21E, size: 30, coder: blake2Bhash),
MHash(name: "blake2b-248", code: 0xB21F, size: 31, coder: blake2Bhash),
MHash(name: "blake2b-256", code: 0xB220, size: 32, coder: blake2Bhash),
MHash(name: "blake2b-264", code: 0xB221, size: 33, coder: blake2Bhash),
MHash(name: "blake2b-272", code: 0xB222, size: 34, coder: blake2Bhash),
MHash(name: "blake2b-280", code: 0xB223, size: 35, coder: blake2Bhash),
MHash(name: "blake2b-288", code: 0xB224, size: 36, coder: blake2Bhash),
MHash(name: "blake2b-296", code: 0xB225, size: 37, coder: blake2Bhash),
MHash(name: "blake2b-304", code: 0xB226, size: 38, coder: blake2Bhash),
MHash(name: "blake2b-312", code: 0xB227, size: 39, coder: blake2Bhash),
MHash(name: "blake2b-320", code: 0xB228, size: 40, coder: blake2Bhash),
MHash(name: "blake2b-328", code: 0xB229, size: 41, coder: blake2Bhash),
MHash(name: "blake2b-336", code: 0xB22A, size: 42, coder: blake2Bhash),
MHash(name: "blake2b-344", code: 0xB22B, size: 43, coder: blake2Bhash),
MHash(name: "blake2b-352", code: 0xB22C, size: 44, coder: blake2Bhash),
MHash(name: "blake2b-360", code: 0xB22D, size: 45, coder: blake2Bhash),
MHash(name: "blake2b-368", code: 0xB22E, size: 46, coder: blake2Bhash),
MHash(name: "blake2b-376", code: 0xB22F, size: 47, coder: blake2Bhash),
MHash(name: "blake2b-384", code: 0xB230, size: 48, coder: blake2Bhash),
MHash(name: "blake2b-392", code: 0xB231, size: 49, coder: blake2Bhash),
MHash(name: "blake2b-400", code: 0xB232, size: 50, coder: blake2Bhash),
MHash(name: "blake2b-408", code: 0xB233, size: 51, coder: blake2Bhash),
MHash(name: "blake2b-416", code: 0xB234, size: 52, coder: blake2Bhash),
MHash(name: "blake2b-424", code: 0xB235, size: 53, coder: blake2Bhash),
MHash(name: "blake2b-432", code: 0xB236, size: 54, coder: blake2Bhash),
MHash(name: "blake2b-440", code: 0xB237, size: 55, coder: blake2Bhash),
MHash(name: "blake2b-448", code: 0xB238, size: 56, coder: blake2Bhash),
MHash(name: "blake2b-456", code: 0xB239, size: 57, coder: blake2Bhash),
MHash(name: "blake2b-464", code: 0xB23A, size: 58, coder: blake2Bhash),
MHash(name: "blake2b-472", code: 0xB23B, size: 59, coder: blake2Bhash),
MHash(name: "blake2b-480", code: 0xB23C, size: 60, coder: blake2Bhash),
MHash(name: "blake2b-488", code: 0xB23D, size: 61, coder: blake2Bhash),
MHash(name: "blake2b-496", code: 0xB23E, size: 62, coder: blake2Bhash),
MHash(name: "blake2b-504", code: 0xB23F, size: 63, coder: blake2Bhash),
MHash(name: "blake2b-512", code: 0xB240, size: 64, coder: blake2Bhash),
MHash(name: "blake2s-8", code: 0xB241, size: 1, coder: blake2Shash),
MHash(name: "blake2s-16", code: 0xB242, size: 2, coder: blake2Shash),
MHash(name: "blake2s-24", code: 0xB243, size: 3, coder: blake2Shash),
MHash(name: "blake2s-32", code: 0xB244, size: 4, coder: blake2Shash),
MHash(name: "blake2s-40", code: 0xB245, size: 5, coder: blake2Shash),
MHash(name: "blake2s-48", code: 0xB246, size: 6, coder: blake2Shash),
MHash(name: "blake2s-56", code: 0xB247, size: 7, coder: blake2Shash),
MHash(name: "blake2s-64", code: 0xB248, size: 8, coder: blake2Shash),
MHash(name: "blake2s-72", code: 0xB249, size: 9, coder: blake2Shash),
MHash(name: "blake2s-80", code: 0xB24A, size: 10, coder: blake2Shash),
MHash(name: "blake2s-88", code: 0xB24B, size: 11, coder: blake2Shash),
MHash(name: "blake2s-96", code: 0xB24C, size: 12, coder: blake2Shash),
MHash(name: "blake2s-104", code: 0xB24D, size: 13, coder: blake2Shash),
MHash(name: "blake2s-112", code: 0xB24E, size: 14, coder: blake2Shash),
MHash(name: "blake2s-120", code: 0xB24F, size: 15, coder: blake2Shash),
MHash(name: "blake2s-128", code: 0xB250, size: 16, coder: blake2Shash),
MHash(name: "blake2s-136", code: 0xB251, size: 17, coder: blake2Shash),
MHash(name: "blake2s-144", code: 0xB252, size: 18, coder: blake2Shash),
MHash(name: "blake2s-152", code: 0xB253, size: 19, coder: blake2Shash),
MHash(name: "blake2s-160", code: 0xB254, size: 20, coder: blake2Shash),
MHash(name: "blake2s-168", code: 0xB255, size: 21, coder: blake2Shash),
MHash(name: "blake2s-176", code: 0xB256, size: 22, coder: blake2Shash),
MHash(name: "blake2s-184", code: 0xB257, size: 23, coder: blake2Shash),
MHash(name: "blake2s-192", code: 0xB258, size: 24, coder: blake2Shash),
MHash(name: "blake2s-200", code: 0xB259, size: 25, coder: blake2Shash),
MHash(name: "blake2s-208", code: 0xB25A, size: 26, coder: blake2Shash),
MHash(name: "blake2s-216", code: 0xB25B, size: 27, coder: blake2Shash),
MHash(name: "blake2s-224", code: 0xB25C, size: 28, coder: blake2Shash),
MHash(name: "blake2s-232", code: 0xB25D, size: 29, coder: blake2Shash),
MHash(name: "blake2s-240", code: 0xB25E, size: 30, coder: blake2Shash),
MHash(name: "blake2s-248", code: 0xB25F, size: 31, coder: blake2Shash),
MHash(name: "blake2s-256", code: 0xB260, size: 32, coder: blake2Shash)
]
proc initMultiHashNameTable(): Table[string, MHash] {.compileTime.} =
result = initTable[string, MHash]()
for item in HashesList:
result[item.name] = item
proc initMultiHashCodeTable(): Table[int, MHash] {.compileTime.} =
result = initTable[int, MHash]()
for item in HashesList:
result[item.code] = item
const
CodeHashes = initMultiHashCodeTable()
NameHashes = initMultiHashNameTable()
proc multihashName*(code: int): string =
## Returns MultiHash digest name from its code.
let hash = CodeHashes.getOrDefault(code)
if isNil(hash.coder):
raise newException(MultiHashError, "Hash not supported")
else:
result = hash.name
proc multihashCode*(name: string): int =
## Returns MultiHash digest code from its name.
let hash = NameHashes.getOrDefault(name)
if isNil(hash.coder):
raise newException(MultiHashError, "Hash not supported")
else:
result = hash.code
proc digestImplWithHash(hash: MHash, data: openarray[byte]): MultiHash =
var buffer: array[MaxHashSize, byte]
result.data = initVBuffer()
result.code = hash.code
result.data.writeVarint(uint(hash.code))
if hash.size == 0:
result.data.writeVarint(uint(len(data)))
result.dpos = len(result.data.buffer)
result.data.writeArray(data)
result.size = len(data)
else:
result.data.writeVarint(uint(hash.size))
result.dpos = len(result.data.buffer)
hash.coder(data, buffer.toOpenArray(0, hash.size - 1))
result.data.writeArray(buffer.toOpenArray(0, hash.size - 1))
result.size = hash.size
proc digestImplWithoutHash(hash: MHash, data: openarray[byte]): MultiHash =
result.data = initVBuffer()
result.code = hash.code
result.size = len(data)
result.data.writeVarint(uint(hash.code))
result.data.writeVarint(uint(len(data)))
result.dpos = len(result.data.buffer)
result.data.writeArray(data)
proc digest*(mhtype: typedesc[MultiHash], hashname: string,
data: openarray[byte]): MultiHash {.inline.} =
## Perform digest calculation using hash algorithm with name ``hashname`` on
## data array ``data``.
let hash = NameHashes.getOrDefault(hashname)
if isNil(hash.coder):
raise newException(MultihashError, "Hash not supported")
result = digestImplWithHash(hash, data)
proc digest*(mhtype: typedesc[MultiHash], hashcode: int,
data: openarray[byte]): MultiHash {.inline.} =
## Perform digest calculation using hash algorithm with code ``hashcode`` on
## data array ``data``.
let hash = CodeHashes.getOrDefault(hashcode)
if isNil(hash.coder):
raise newException(MultihashError, "Hash not supported")
result = digestImplWithHash(hash, data)
proc init*[T](mhtype: typedesc[MultiHash], hashname: string,
mdigest: MDigest[T]): MultiHash {.inline.} =
## Create MultiHash from nimcrypto's `MDigest` object and hash algorithm name
## ``hashname``.
let hash = NameHashes.getOrDefault(hashname)
if isNil(hash.coder):
raise newException(MultihashError, "Hash not supported")
if hash.size != len(mdigest.data):
raise newException(MultiHashError, "Incorrect MDigest[T] size")
result = digestImplWithoutHash(hash, mdigest.data)
proc init*[T](mhtype: typedesc[MultiHash], hashcode: int,
mdigest: MDigest[T]): MultiHash {.inline.} =
## Create MultiHash from nimcrypto's `MDigest` and hash algorithm code
## ``hashcode``.
let hash = CodeHashes.getOrDefault(hashcode)
if isNil(hash.coder):
raise newException(MultihashError, "Hash not supported")
if (hash.size != 0) and (hash.size != len(mdigest.data)):
raise newException(MultiHashError, "Incorrect MDigest[T] size")
result = digestImplWithoutHash(hash, mdigest.data)
proc init*(mhtype: typedesc[MultiHash], hashname: string,
bdigest: openarray[byte]): MultiHash {.inline.} =
## Create MultiHash from array of bytes ``bdigest`` and hash algorithm code
## ``hashcode``.
let hash = NameHashes.getOrDefault(hashname)
if isNil(hash.coder):
raise newException(MultihashError, "Hash not supported")
if (hash.size != 0) and (hash.size != len(bdigest)):
raise newException(MultiHashError, "Incorrect bdigest size")
result = digestImplWithoutHash(hash, bdigest)
proc init*(mhtype: typedesc[MultiHash], hashcode: int,
bdigest: openarray[byte]): MultiHash {.inline.} =
## Create MultiHash from array of bytes ``bdigest`` and hash algorithm code
## ``hashcode``.
let hash = CodeHashes.getOrDefault(hashcode)
if isNil(hash.coder):
raise newException(MultihashError, "Hash not supported")
if (hash.size != 0) and (hash.size != len(bdigest)):
raise newException(MultiHashError, "Incorrect bdigest size")
result = digestImplWithoutHash(hash, bdigest)
proc decode*(mhtype: typedesc[MultiHash], data: openarray[byte],
mhash: var MultiHash): int =
## Decode MultiHash value from array of bytes ``data``.
##
## On success decoded MultiHash will be stored into ``mhash`` and number of
## bytes consumed will be returned.
##
## On error ``-1`` will be returned.
var code, size: uint64
var res, dpos: int
if len(data) < 2:
return -1
var vb = initVBuffer(data)
if vb.isEmpty():
return -1
res = vb.readVarint(code)
if res == -1:
return -1
dpos += res
res = vb.readVarint(size)
if res == -1:
return -1
dpos += res
if size > 0x7FFF_FFFF'u64:
return -1
let hash = CodeHashes.getOrDefault(int(code))
if isNil(hash.coder):
return -1
if (hash.size != 0) and (hash.size != int(size)):
return -1
if not vb.isEnough(int(size)):
return -1
mhash = MultiHash.init(int(code),
vb.buffer.toOpenArray(vb.offset,
vb.offset + int(size) - 1))
result = vb.offset + int(size)
proc init*(mhtype: typedesc[MultiHash],
data: openarray[byte]): MultiHash {.inline.} =
## Create MultiHash from bytes array ``data``.
if MultiHash.decode(data, result) == -1:
raise newException(MultihashError, "Incorrect MultiHash binary format")
proc init*(mhtype: typedesc[MultiHash], data: string): MultiHash {.inline.} =
## Create MultiHash from hexadecimal string representation ``data``.
if MultiHash.decode(fromHex(data), result) == -1:
raise newException(MultihashError, "Incorrect MultiHash binary format")
proc init58*(mhtype: typedesc[MultiHash],
data: string): MultiHash {.inline.} =
## Create MultiHash from BASE58 encoded string representation ``data``.
if MultiHash.decode(Base58.decode(data), result) == -1:
raise newException(MultihashError, "Incorrect MultiHash binary format")
proc cmp(a: openarray[byte], b: openarray[byte]): bool {.inline.} =
if len(a) != len(b):
return false
var n = len(a)
var res, diff: int
while n > 0:
dec(n)
diff = int(a[n]) - int(b[n])
res = (res and -not(diff)) or diff
result = (res == 0)
proc `==`*[T](mh: MultiHash, mdigest: MDigest[T]): bool =
## Compares MultiHash with nimcrypto's MDigest[T], returns ``true`` if
## hashes are equal, ``false`` otherwise.
if mh.dpos == 0:
return false
if len(mdigest.data) != mh.size:
return false
result = cmp(mh.data.buffer.toOpenArray(mh.dpos, mh.dpos + mh.size - 1),
mdigest.data.toOpenArray(0, len(mdigest.data) - 1))
proc `==`*[T](mdigest: MDigest[T], mh: MultiHash): bool {.inline.} =
## Compares MultiHash with nimcrypto's MDigest[T], returns ``true`` if
## hashes are equal, ``false`` otherwise.
result = `==`(mh, mdigest)
proc `==`*(a, b: MultiHash): bool =
## Compares MultiHashes ``a`` and ``b``, returns ``true`` if
## hashes are equal, ``false`` otherwise.
if a.dpos == 0 and b.dpos == 0:
return true
if a.code != b.code:
return false
if a.size != b.size:
return false
result = cmp(a.data.buffer.toOpenArray(a.dpos, a.dpos + a.size - 1),
b.data.buffer.toOpenArray(b.dpos, b.dpos + b.size - 1))
proc hex*(value: MultiHash): string =
## Return hexadecimal string representation of MultiHash ``value``.
result = $(value.data)
proc base58*(value: MultiHash): string =
## Return Base58 encoded string representation of MultiHash ``value``.
result = Base58.encode(value.data.buffer)
proc `$`*(value: MultiHash): string =
## Return string representation of MultiHash ``value``.
let digest = toHex(value.data.buffer.toOpenArray(value.dpos,
value.dpos + value.size - 1))
result = multihashName(value.code) & "/" & digest
when isMainModule:
echo MultiHash.init58("QmPGqitiRv1TPuCNtcwsMNRPEhx9SZP5qANPNcQBA53BgM")