nimbus-eth1/nimbus/vm/utils/utils_numeric.nim

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# Nimbus
# Copyright (c) 2018 Status Research & Development GmbH
# Licensed under either of
# * Apache License, version 2.0, ([LICENSE-APACHE](LICENSE-APACHE) or http://www.apache.org/licenses/LICENSE-2.0)
# * MIT license ([LICENSE-MIT](LICENSE-MIT) or http://opensource.org/licenses/MIT)
# at your option. This file may not be copied, modified, or distributed except according to those terms.
import
stint, strformat, strutils, sequtils, endians, macros, rlp,
../../constants, ../../utils/padding
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# some methods based on py-evm utils/numeric
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proc bigEndianToInt*(value: openarray[byte]): UInt256 =
if value.len == 32:
readUintBE[256](value)
else:
readUintBE[256](padLeft(@value, 32, 0.byte))
proc log256*(value: UInt256): Natural =
(255 - value.countLeadingZeroBits) div 8 # Compilers optimize to `shr 3`
proc unsignedToPseudoSigned*(value: UInt256): UInt256 =
result = value
if value > INT_256_MAX_AS_UINT256:
result -= INT_256_MAX_AS_UINT256
proc pseudoSignedToUnsigned*(value: UInt256): UInt256 =
result = value
if value > INT_256_MAX_AS_UINT256:
result += INT_256_MAX_AS_UINT256
func ceil32*(value: Natural): Natural {.inline.}=
# Round input to the nearest bigger multiple of 32
result = value
let remainder = result and 31 # equivalent to modulo 32
if remainder != 0:
return value + 32 - remainder
func wordCount*(length: Natural): Natural {.inline.}=
# Returns the number of EVM words corresponding to a specific size.
# EVM words is rounded up
length.ceil32 shr 5 # equivalent to `div 32` (32 = 2^5)