2018-11-19 02:52:11 +00:00
|
|
|
## 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.
|
|
|
|
|
2018-11-20 21:39:35 +00:00
|
|
|
## This module implements Variable Integer `VARINT`.
|
|
|
|
## This module supports two variants of variable integer
|
|
|
|
## - Google ProtoBuf varint, which is able to encode full uint64 number and
|
|
|
|
## maximum size of encoded value is 10 octets (bytes).
|
2020-01-29 09:14:25 +00:00
|
|
|
## https://developers.google.com/protocol-buffers/docs/encoding#varints
|
2018-11-20 21:39:35 +00:00
|
|
|
## - LibP2P varint, which is able to encode only 63bits of uint64 number and
|
|
|
|
## maximum size of encoded value is 9 octets (bytes).
|
2020-01-29 09:14:25 +00:00
|
|
|
## https://github.com/multiformats/unsigned-varint
|
2020-03-06 19:19:43 +00:00
|
|
|
import bitops, typetraits
|
2018-11-19 02:52:11 +00:00
|
|
|
|
|
|
|
type
|
2018-11-23 10:16:35 +00:00
|
|
|
VarintStatus* {.pure.} = enum
|
2018-11-19 02:52:11 +00:00
|
|
|
Error,
|
|
|
|
Success,
|
|
|
|
Overflow,
|
|
|
|
Incomplete,
|
2020-01-28 15:29:42 +00:00
|
|
|
Overlong,
|
2018-11-19 02:52:11 +00:00
|
|
|
Overrun
|
|
|
|
|
2018-11-20 21:39:35 +00:00
|
|
|
PB* = object
|
|
|
|
## Use this type to specify Google ProtoBuf's varint encoding
|
|
|
|
LP* = object
|
|
|
|
## Use this type to specify LibP2P varint encoding
|
|
|
|
|
2020-03-06 19:19:43 +00:00
|
|
|
zint32* = distinct int32
|
|
|
|
zint64* = distinct int64
|
|
|
|
zint* = distinct int
|
|
|
|
## Signed integer types which will be encoded using zigzag encoding.
|
|
|
|
|
|
|
|
hint32* = distinct int32
|
|
|
|
hint64* = distinct int64
|
|
|
|
hint* = distinct int
|
|
|
|
## Signed integer types which will be encoded using simple cast.
|
|
|
|
|
2018-11-20 21:39:35 +00:00
|
|
|
PBSomeUVarint* = uint | uint64 | uint32
|
2020-03-06 19:19:43 +00:00
|
|
|
PBSomeSVarint* = hint | hint64 | hint32
|
|
|
|
PBZigVarint* = zint | zint64 | zint32
|
|
|
|
PBSomeVarint* = PBSomeUVarint | PBSomeSVarint | PBZigVarint
|
2018-11-20 21:39:35 +00:00
|
|
|
LPSomeUVarint* = uint | uint64 | uint32 | uint16 | uint8
|
|
|
|
LPSomeVarint* = LPSomeUVarint
|
|
|
|
SomeVarint* = PBSomeVarint | LPSomeVarint
|
|
|
|
SomeUVarint* = PBSomeUVarint | LPSomeUVarint
|
2019-06-10 20:33:36 +00:00
|
|
|
VarintError* = object of CatchableError
|
2018-11-19 02:52:11 +00:00
|
|
|
|
2020-03-06 19:19:43 +00:00
|
|
|
proc vsizeof*(x: SomeUVarint): int {.inline.} =
|
2018-11-19 02:52:11 +00:00
|
|
|
## Returns number of bytes required to encode integer ``x`` as varint.
|
2020-03-06 19:19:43 +00:00
|
|
|
if x == type(x)(0):
|
|
|
|
1
|
2018-11-19 02:52:11 +00:00
|
|
|
else:
|
2020-03-06 19:19:43 +00:00
|
|
|
(fastLog2(x) + 1 + 7 - 1) div 7
|
|
|
|
|
|
|
|
proc vsizeof*(x: PBSomeSVarint): int {.inline.} =
|
|
|
|
## Returns number of bytes required to encode signed integer ``x``.
|
|
|
|
##
|
|
|
|
## Note: This procedure interprets signed integer as ProtoBuffer's
|
|
|
|
## ``int32`` and ``int64`` integers.
|
|
|
|
when sizeof(x) == 8:
|
|
|
|
if int64(x) == 0'i64:
|
|
|
|
1
|
|
|
|
else:
|
|
|
|
(fastLog2(uint64(x)) + 1 + 7 - 1) div 7
|
|
|
|
else:
|
|
|
|
if int32(x) == 0'i32:
|
|
|
|
1
|
|
|
|
else:
|
|
|
|
(fastLog2(uint32(x)) + 1 + 7 - 1) div 7
|
|
|
|
|
|
|
|
proc vsizeof*(x: PBZigVarint): int {.inline.} =
|
|
|
|
## Returns number of bytes required to encode signed integer ``x``.
|
|
|
|
##
|
|
|
|
## Note: This procedure interprets signed integer as ProtoBuffer's
|
|
|
|
## ``sint32`` and ``sint64`` integer.
|
|
|
|
when sizeof(x) == 8:
|
|
|
|
if int64(x) == 0'i64:
|
|
|
|
1
|
|
|
|
else:
|
|
|
|
if int64(x) < 0'i64:
|
|
|
|
vsizeof(not(uint64(x) shl 1))
|
|
|
|
else:
|
|
|
|
vsizeof(uint64(x) shl 1)
|
|
|
|
else:
|
|
|
|
if int32(x) == 0'i32:
|
|
|
|
1
|
|
|
|
else:
|
|
|
|
if int32(x) < 0'i32:
|
|
|
|
vsizeof(not(uint32(x) shl 1))
|
|
|
|
else:
|
|
|
|
vsizeof(uint32(x) shl 1)
|
2018-11-19 02:52:11 +00:00
|
|
|
|
2018-11-20 21:39:35 +00:00
|
|
|
proc getUVarint*[T: PB|LP](vtype: typedesc[T],
|
|
|
|
pbytes: openarray[byte],
|
|
|
|
outlen: var int,
|
|
|
|
outval: var SomeUVarint): VarintStatus =
|
2018-11-19 02:52:11 +00:00
|
|
|
## Decode `unsigned varint` from buffer ``pbytes`` and store it to ``outval``.
|
|
|
|
## On success ``outlen`` will be set to number of bytes processed while
|
|
|
|
## decoding `unsigned varint`.
|
|
|
|
##
|
|
|
|
## If array ``pbytes`` is empty, ``Incomplete`` error will be returned.
|
|
|
|
##
|
|
|
|
## If there not enough bytes available in array ``pbytes`` to decode `unsigned
|
|
|
|
## varint`, ``Incomplete`` error will be returned.
|
|
|
|
##
|
|
|
|
## If encoded value can produce integer overflow, ``Overflow`` error will be
|
|
|
|
## returned.
|
|
|
|
##
|
2018-11-20 21:39:35 +00:00
|
|
|
## Google ProtoBuf
|
|
|
|
## When decoding 10th byte of Google Protobuf's 64bit integer only 1 bit from
|
|
|
|
## byte will be decoded, all other bits will be ignored. When decoding 5th
|
|
|
|
## byte of 32bit integer only 4 bits from byte will be decoded, all other bits
|
|
|
|
## will be ignored.
|
2019-06-13 09:05:03 +00:00
|
|
|
##
|
2018-11-20 21:39:35 +00:00
|
|
|
## LibP2P
|
|
|
|
## When decoding 5th byte of 32bit integer only 4 bits from byte will be
|
|
|
|
## decoded, all other bits will be ignored.
|
|
|
|
when vtype is PB:
|
|
|
|
const MaxBits = byte(sizeof(outval) * 8)
|
|
|
|
else:
|
|
|
|
when sizeof(outval) == 8:
|
|
|
|
const MaxBits = 63'u8
|
|
|
|
else:
|
|
|
|
const MaxBits = byte(sizeof(outval) * 8)
|
|
|
|
|
2018-11-19 02:52:11 +00:00
|
|
|
var shift = 0'u8
|
|
|
|
result = VarintStatus.Incomplete
|
|
|
|
outlen = 0
|
2020-03-06 19:19:43 +00:00
|
|
|
outval = type(outval)(0)
|
2018-11-19 02:52:11 +00:00
|
|
|
for i in 0..<len(pbytes):
|
|
|
|
let b = pbytes[i]
|
|
|
|
if shift >= MaxBits:
|
|
|
|
result = VarintStatus.Overflow
|
|
|
|
outlen = 0
|
2020-03-06 19:19:43 +00:00
|
|
|
outval = type(outval)(0)
|
2018-11-19 02:52:11 +00:00
|
|
|
break
|
|
|
|
else:
|
2020-03-06 19:19:43 +00:00
|
|
|
outval = outval or (type(outval)(b and 0x7F'u8) shl shift)
|
2018-11-19 02:52:11 +00:00
|
|
|
shift += 7
|
|
|
|
inc(outlen)
|
|
|
|
if (b and 0x80'u8) == 0'u8:
|
|
|
|
result = VarintStatus.Success
|
|
|
|
break
|
|
|
|
if result == VarintStatus.Incomplete:
|
|
|
|
outlen = 0
|
2020-03-06 19:19:43 +00:00
|
|
|
outval = type(outval)(0)
|
2018-11-19 02:52:11 +00:00
|
|
|
|
2020-01-28 15:29:42 +00:00
|
|
|
when vtype is LP:
|
|
|
|
if result == VarintStatus.Success:
|
|
|
|
if outlen != vsizeof(outval):
|
2020-03-06 19:19:43 +00:00
|
|
|
outval = type(outval)(0)
|
2020-01-28 15:29:42 +00:00
|
|
|
outlen = 0
|
|
|
|
result = VarintStatus.Overlong
|
|
|
|
|
2018-11-20 21:39:35 +00:00
|
|
|
proc putUVarint*[T: PB|LP](vtype: typedesc[T],
|
|
|
|
pbytes: var openarray[byte],
|
|
|
|
outlen: var int,
|
|
|
|
outval: SomeUVarint): VarintStatus =
|
2018-11-19 02:52:11 +00:00
|
|
|
## Encode `unsigned varint` ``outval`` and store it to array ``pbytes``.
|
|
|
|
##
|
|
|
|
## On success ``outlen`` will hold number of bytes (octets) used to encode
|
|
|
|
## unsigned integer ``v``.
|
|
|
|
##
|
|
|
|
## If there not enough bytes available in buffer ``pbytes``, ``Incomplete``
|
|
|
|
## error will be returned and ``outlen`` will be set to number of bytes
|
|
|
|
## required.
|
|
|
|
##
|
2018-11-20 21:39:35 +00:00
|
|
|
## Google ProtoBuf
|
2018-11-19 02:52:11 +00:00
|
|
|
## Maximum encoded length of 64bit integer is 10 octets.
|
|
|
|
## Maximum encoded length of 32bit integer is 5 octets.
|
2019-06-13 09:05:03 +00:00
|
|
|
##
|
2018-11-20 21:39:35 +00:00
|
|
|
## LibP2P
|
|
|
|
## Maximum encoded length of 63bit integer is 9 octets.
|
|
|
|
## Maximum encoded length of 32bit integer is 5 octets.
|
2018-11-19 02:52:11 +00:00
|
|
|
var buffer: array[10, byte]
|
|
|
|
var value = outval
|
|
|
|
var k = 0
|
|
|
|
|
2018-11-20 21:39:35 +00:00
|
|
|
when vtype is LP:
|
|
|
|
if sizeof(outval) == 8:
|
2020-03-06 19:19:43 +00:00
|
|
|
if (uint64(outval) and 0x8000_0000_0000_0000'u64) != 0'u64:
|
2018-11-20 21:39:35 +00:00
|
|
|
result = Overflow
|
|
|
|
return
|
|
|
|
|
2020-03-06 19:19:43 +00:00
|
|
|
if value <= type(outval)(0x7F):
|
|
|
|
buffer[0] = byte(outval and 0xFF)
|
2018-11-19 02:52:11 +00:00
|
|
|
inc(k)
|
|
|
|
else:
|
2020-03-06 19:19:43 +00:00
|
|
|
while value != type(outval)(0):
|
|
|
|
buffer[k] = byte((value and 0x7F) or 0x80)
|
2018-11-19 02:52:11 +00:00
|
|
|
value = value shr 7
|
|
|
|
inc(k)
|
|
|
|
buffer[k - 1] = buffer[k - 1] and 0x7F'u8
|
|
|
|
|
|
|
|
outlen = k
|
|
|
|
if len(pbytes) >= k:
|
|
|
|
copyMem(addr pbytes[0], addr buffer[0], k)
|
|
|
|
result = VarintStatus.Success
|
|
|
|
else:
|
|
|
|
result = VarintStatus.Overrun
|
|
|
|
|
|
|
|
proc getSVarint*(pbytes: openarray[byte], outsize: var int,
|
2018-11-20 21:39:35 +00:00
|
|
|
outval: var PBSomeSVarint): VarintStatus {.inline.} =
|
2020-03-06 19:19:43 +00:00
|
|
|
## Decode signed integer (``int32`` or ``int64``) from buffer ``pbytes``
|
|
|
|
## and store it to ``outval``.
|
|
|
|
##
|
|
|
|
## On success ``outlen`` will be set to number of bytes processed while
|
|
|
|
## decoding signed varint.
|
2018-11-19 02:52:11 +00:00
|
|
|
##
|
|
|
|
## If array ``pbytes`` is empty, ``Incomplete`` error will be returned.
|
|
|
|
##
|
|
|
|
## If there not enough bytes available in array ``pbytes`` to decode `signed
|
|
|
|
## varint`, ``Incomplete`` error will be returned.
|
|
|
|
##
|
|
|
|
## If encoded value can produce integer overflow, ``Overflow`` error will be
|
|
|
|
## returned.
|
|
|
|
##
|
|
|
|
## Note, when decoding 10th byte of 64bit integer only 1 bit from byte will be
|
|
|
|
## decoded, all other bits will be ignored. When decoding 5th byte of 32bit
|
|
|
|
## integer only 4 bits from byte will be decoded, all other bits will be
|
|
|
|
## ignored.
|
|
|
|
when sizeof(outval) == 8:
|
|
|
|
var value: uint64
|
|
|
|
else:
|
|
|
|
var value: uint32
|
|
|
|
|
2018-11-20 21:39:35 +00:00
|
|
|
result = PB.getUVarint(pbytes, outsize, value)
|
2018-11-19 02:52:11 +00:00
|
|
|
if result == VarintStatus.Success:
|
2020-03-06 19:19:43 +00:00
|
|
|
outval = cast[type(outval)](value)
|
|
|
|
|
|
|
|
proc getSVarint*(pbytes: openarray[byte], outsize: var int,
|
|
|
|
outval: var PBZigVarint): VarintStatus {.inline.} =
|
|
|
|
## Decode Google ProtoBuf's zigzag encoded signed integer (``sint32`` or
|
|
|
|
## ``sint64`` ) from buffer ``pbytes`` and store it to ``outval``.
|
|
|
|
##
|
|
|
|
## On success ``outlen`` will be set to number of bytes processed while
|
|
|
|
## decoding signed varint.
|
|
|
|
##
|
|
|
|
## If array ``pbytes`` is empty, ``Incomplete`` error will be returned.
|
|
|
|
##
|
|
|
|
## If there not enough bytes available in array ``pbytes`` to decode `signed
|
|
|
|
## varint`, ``Incomplete`` error will be returned.
|
|
|
|
##
|
|
|
|
## If encoded value can produce integer overflow, ``Overflow`` error will be
|
|
|
|
## returned.
|
|
|
|
##
|
|
|
|
## Note, when decoding 10th byte of 64bit integer only 1 bit from byte will be
|
|
|
|
## decoded, all other bits will be ignored. When decoding 5th byte of 32bit
|
|
|
|
## integer only 4 bits from byte will be decoded, all other bits will be
|
|
|
|
## ignored.
|
|
|
|
when sizeof(outval) == 8:
|
|
|
|
var value: uint64
|
|
|
|
else:
|
|
|
|
var value: uint32
|
|
|
|
|
|
|
|
result = PB.getUVarint(pbytes, outsize, value)
|
|
|
|
if result == VarintStatus.Success:
|
|
|
|
if (value and type(value)(1)) != type(value)(0):
|
2018-11-19 02:52:11 +00:00
|
|
|
outval = cast[type(outval)](not(value shr 1))
|
|
|
|
else:
|
|
|
|
outval = cast[type(outval)](value shr 1)
|
|
|
|
|
|
|
|
proc putSVarint*(pbytes: var openarray[byte], outsize: var int,
|
2020-03-06 19:19:43 +00:00
|
|
|
outval: PBZigVarint): VarintStatus {.inline.} =
|
|
|
|
## Encode signed integer ``outval`` using ProtoBuffer's zigzag encoding
|
|
|
|
## (``sint32`` or ``sint64``) and store it to array ``pbytes``.
|
2018-11-19 02:52:11 +00:00
|
|
|
##
|
|
|
|
## On success ``outlen`` will hold number of bytes (octets) used to encode
|
|
|
|
## unsigned integer ``v``.
|
|
|
|
##
|
|
|
|
## If there not enough bytes available in buffer ``pbytes``, ``Incomplete``
|
|
|
|
## error will be returned and ``outlen`` will be set to number of bytes
|
|
|
|
## required.
|
|
|
|
##
|
|
|
|
## Maximum encoded length of 64bit integer is 10 octets.
|
|
|
|
## Maximum encoded length of 32bit integer is 5 octets.
|
|
|
|
when sizeof(outval) == 8:
|
|
|
|
var value: uint64 =
|
2020-03-06 19:19:43 +00:00
|
|
|
if int64(outval) < 0'i64:
|
|
|
|
not(uint64(outval) shl 1)
|
2018-11-19 02:52:11 +00:00
|
|
|
else:
|
2020-03-06 19:19:43 +00:00
|
|
|
uint64(outval) shl 1
|
2018-11-19 02:52:11 +00:00
|
|
|
else:
|
|
|
|
var value: uint32 =
|
2020-03-06 19:19:43 +00:00
|
|
|
if int32(outval) < 0'i32:
|
|
|
|
not(uint32(outval) shl 1)
|
2018-11-19 02:52:11 +00:00
|
|
|
else:
|
2020-03-06 19:19:43 +00:00
|
|
|
uint32(outval) shl 1
|
2018-11-20 21:39:35 +00:00
|
|
|
result = PB.putUVarint(pbytes, outsize, value)
|
2018-11-19 02:52:11 +00:00
|
|
|
|
2020-03-06 19:19:43 +00:00
|
|
|
proc putSVarint*(pbytes: var openarray[byte], outsize: var int,
|
|
|
|
outval: PBSomeSVarint): VarintStatus {.inline.} =
|
|
|
|
## Encode signed integer ``outval`` (``int32`` or ``int64``) and store it to
|
|
|
|
## array ``pbytes``.
|
|
|
|
##
|
|
|
|
## On success ``outlen`` will hold number of bytes (octets) used to encode
|
|
|
|
## unsigned integer ``v``.
|
|
|
|
##
|
|
|
|
## If there not enough bytes available in buffer ``pbytes``, ``Incomplete``
|
|
|
|
## error will be returned and ``outlen`` will be set to number of bytes
|
|
|
|
## required.
|
|
|
|
##
|
|
|
|
## Maximum encoded length of 64bit integer is 10 octets.
|
|
|
|
## Maximum encoded length of 32bit integer is 5 octets.
|
|
|
|
when sizeof(outval) == 8:
|
|
|
|
result = PB.putUVarint(pbytes, outsize, uint64(outval))
|
|
|
|
else:
|
|
|
|
result = PB.putUVarint(pbytes, outsize, uint32(outval))
|
|
|
|
|
|
|
|
template varintFatal(msg) =
|
|
|
|
const m = msg
|
|
|
|
{.fatal: m.}
|
|
|
|
|
|
|
|
proc putVarint*[T: PB|LP](vtype: typedesc[T], pbytes: var openarray[byte],
|
|
|
|
nbytes: var int, value: SomeVarint): VarintStatus {.inline.} =
|
|
|
|
when vtype is PB:
|
|
|
|
when (type(value) is PBSomeSVarint) or (type(value) is PBZigVarint):
|
|
|
|
result = putSVarint(pbytes, nbytes, value)
|
|
|
|
elif (type(value) is PBSomeUVarint):
|
|
|
|
result = PB.putUVarint(pbytes, nbytes, value)
|
|
|
|
else:
|
|
|
|
varintFatal("Protobuf's varint do not support type [" &
|
|
|
|
typetraits.name(type(value)) & "]")
|
|
|
|
elif vtype is LP:
|
|
|
|
when (type(value) is LPSomeVarint):
|
|
|
|
result = LP.putUVarint(pbytes, nbytes, value)
|
|
|
|
else:
|
|
|
|
varintFatal("LibP2P's varint do not support type [" &
|
|
|
|
typetraits.name(type(value)) & "]")
|
|
|
|
|
|
|
|
proc getVarint*[T: PB|LP](vtype: typedesc[T], pbytes: openarray[byte],
|
|
|
|
nbytes: var int,
|
|
|
|
value: var SomeVarint): VarintStatus {.inline.} =
|
|
|
|
when vtype is PB:
|
|
|
|
when (type(value) is PBSomeSVarint) or (type(value) is PBZigVarint):
|
|
|
|
result = getSVarint(pbytes, nbytes, value)
|
|
|
|
elif (type(value) is PBSomeUVarint):
|
|
|
|
result = PB.getUVarint(pbytes, nbytes, value)
|
|
|
|
else:
|
|
|
|
varintFatal("Protobuf's varint do not support type [" &
|
|
|
|
typetraits.name(type(value)) & "]")
|
|
|
|
elif vtype is LP:
|
|
|
|
when (type(value) is LPSomeVarint):
|
|
|
|
result = LP.getUVarint(pbytes, nbytes, value)
|
|
|
|
else:
|
|
|
|
varintFatal("LibP2P's varint do not support type [" &
|
|
|
|
typetraits.name(type(value)) & "]")
|
|
|
|
|
2018-11-20 21:39:35 +00:00
|
|
|
proc encodeVarint*(vtype: typedesc[PB],
|
|
|
|
value: PBSomeVarint): seq[byte] {.inline.} =
|
|
|
|
## Encode integer to Google ProtoBuf's `signed/unsigned varint` and returns
|
|
|
|
## sequence of bytes as result.
|
2018-11-19 02:52:11 +00:00
|
|
|
var outsize = 0
|
|
|
|
result = newSeqOfCap[byte](10)
|
|
|
|
when sizeof(value) == 4:
|
|
|
|
result.setLen(5)
|
|
|
|
else:
|
|
|
|
result.setLen(10)
|
2020-03-06 19:19:43 +00:00
|
|
|
when (type(value) is PBSomeSVarint) or (type(value) is PBZigVarint):
|
2018-11-19 02:52:11 +00:00
|
|
|
let res = putSVarint(result, outsize, value)
|
|
|
|
else:
|
2019-06-13 09:05:03 +00:00
|
|
|
let res = PB.putUVarint(result, outsize, value)
|
2018-11-19 02:52:11 +00:00
|
|
|
if res == VarintStatus.Success:
|
|
|
|
result.setLen(outsize)
|
|
|
|
else:
|
|
|
|
raise newException(VarintError, "Error '" & $res & "'")
|
|
|
|
|
2018-11-20 21:39:35 +00:00
|
|
|
proc encodeVarint*(vtype: typedesc[LP],
|
|
|
|
value: LPSomeVarint): seq[byte] {.inline.} =
|
|
|
|
## Encode integer to LibP2P `unsigned varint` and returns sequence of bytes
|
|
|
|
## as result.
|
|
|
|
var outsize = 0
|
|
|
|
result = newSeqOfCap[byte](9)
|
|
|
|
when sizeof(value) == 1:
|
|
|
|
result.setLen(2)
|
|
|
|
elif sizeof(value) == 2:
|
|
|
|
result.setLen(3)
|
|
|
|
elif sizeof(value) == 4:
|
|
|
|
result.setLen(5)
|
|
|
|
else:
|
|
|
|
result.setLen(9)
|
|
|
|
let res = LP.putUVarint(result, outsize, value)
|
|
|
|
if res == VarintStatus.Success:
|
|
|
|
result.setLen(outsize)
|
|
|
|
else:
|
|
|
|
raise newException(VarintError, "Error '" & $res & "'")
|