nimbus-eth1/nimbus/vm/memory.nim

62 lines
1.8 KiB
Nim

# 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
sequtils,
chronicles, eth/common/eth_types,
../errors, ../validation,
./interpreter/utils/utils_numeric
logScope:
topics = "vm memory"
type
Memory* = ref object
bytes*: seq[byte]
proc newMemory*: Memory =
new(result)
result.bytes = @[]
proc len*(memory: Memory): int =
result = memory.bytes.len
proc extend*(memory: var Memory; startPos: Natural; size: Natural) =
if size == 0:
return
var newSize = ceil32(startPos + size)
if newSize <= len(memory):
return
var sizeToExtend = newSize - len(memory)
memory.bytes = memory.bytes.concat(repeat(0.byte, sizeToExtend))
proc newMemory*(size: Natural): Memory =
result = newMemory()
result.extend(0, size)
proc read*(memory: var Memory, startPos: Natural, size: Natural): seq[byte] =
# TODO: use an openarray[byte]
result = memory.bytes[startPos ..< (startPos + size)]
when defined(evmc_enabled):
proc readPtr*(memory: var Memory, startPos: Natural): ptr byte =
if memory.bytes.len == 0 or startPos >= memory.bytes.len: return
result = memory.bytes[startPos].addr
proc write*(memory: var Memory, startPos: Natural, value: openarray[byte]) =
let size = value.len
if size == 0:
return
#echo size
#echo startPos
validateLte(startPos + size, memory.len)
if memory.len < startPos + size:
memory.bytes = memory.bytes.concat(repeat(0.byte, memory.len - (startPos + size))) # TODO: better logarithmic scaling?
for z, b in value:
memory.bytes[z + startPos] = b