Permalink
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
this commit optimizes the make_byte_array_copier and make_dynarray_copier routines. specifically, it reduces the number of words to copy in the main loop by 1. for batch copies (memory/calldata/code -> memory), this reduces gas by 3, and for non-batch copies (e.g. storage -> memory), this reduces gas by one loop iteration and one read. importantly, when the number of bytes is small (e.g. copy Bytes[32]), this triggers an optimization in `copy_bytes` so the whole copy operation is a single load/store (plus the load/store for the length)
147 lines (124 sloc)
5.04 KB
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
# @dev Implementation of ERC-20 token standard. | |
# @author Takayuki Jimba (@yudetamago) | |
# https://github.com/ethereum/EIPs/blob/master/EIPS/eip-20.md | |
from vyper.interfaces import ERC20 | |
from vyper.interfaces import ERC20Detailed | |
implements: ERC20 | |
implements: ERC20Detailed | |
event Transfer: | |
sender: indexed(address) | |
receiver: indexed(address) | |
value: uint256 | |
event Approval: | |
owner: indexed(address) | |
spender: indexed(address) | |
value: uint256 | |
name: public(String[32]) | |
symbol: public(String[32]) | |
decimals: public(uint8) | |
# NOTE: By declaring `balanceOf` as public, vyper automatically generates a 'balanceOf()' getter | |
# method to allow access to account balances. | |
# The _KeyType will become a required parameter for the getter and it will return _ValueType. | |
# See: https://vyper.readthedocs.io/en/v0.1.0-beta.8/types.html?highlight=getter#mappings | |
balanceOf: public(HashMap[address, uint256]) | |
# By declaring `allowance` as public, vyper automatically generates the `allowance()` getter | |
allowance: public(HashMap[address, HashMap[address, uint256]]) | |
# By declaring `totalSupply` as public, we automatically create the `totalSupply()` getter | |
totalSupply: public(uint256) | |
minter: address | |
@external | |
def __init__(_name: String[32], _symbol: String[32], _decimals: uint8, _supply: uint256): | |
init_supply: uint256 = _supply * 10 ** convert(_decimals, uint256) | |
self.name = _name | |
self.symbol = _symbol | |
self.decimals = _decimals | |
self.balanceOf[msg.sender] = init_supply | |
self.totalSupply = init_supply | |
self.minter = msg.sender | |
log Transfer(ZERO_ADDRESS, msg.sender, init_supply) | |
@external | |
def transfer(_to : address, _value : uint256) -> bool: | |
""" | |
@dev Transfer token for a specified address | |
@param _to The address to transfer to. | |
@param _value The amount to be transferred. | |
""" | |
# NOTE: vyper does not allow underflows | |
# so the following subtraction would revert on insufficient balance | |
self.balanceOf[msg.sender] -= _value | |
self.balanceOf[_to] += _value | |
log Transfer(msg.sender, _to, _value) | |
return True | |
@external | |
def transferFrom(_from : address, _to : address, _value : uint256) -> bool: | |
""" | |
@dev Transfer tokens from one address to another. | |
@param _from address The address which you want to send tokens from | |
@param _to address The address which you want to transfer to | |
@param _value uint256 the amount of tokens to be transferred | |
""" | |
# NOTE: vyper does not allow underflows | |
# so the following subtraction would revert on insufficient balance | |
self.balanceOf[_from] -= _value | |
self.balanceOf[_to] += _value | |
# NOTE: vyper does not allow underflows | |
# so the following subtraction would revert on insufficient allowance | |
self.allowance[_from][msg.sender] -= _value | |
log Transfer(_from, _to, _value) | |
return True | |
@external | |
def approve(_spender : address, _value : uint256) -> bool: | |
""" | |
@dev Approve the passed address to spend the specified amount of tokens on behalf of msg.sender. | |
Beware that changing an allowance with this method brings the risk that someone may use both the old | |
and the new allowance by unfortunate transaction ordering. One possible solution to mitigate this | |
race condition is to first reduce the spender's allowance to 0 and set the desired value afterwards: | |
https://github.com/ethereum/EIPs/issues/20#issuecomment-263524729 | |
@param _spender The address which will spend the funds. | |
@param _value The amount of tokens to be spent. | |
""" | |
self.allowance[msg.sender][_spender] = _value | |
log Approval(msg.sender, _spender, _value) | |
return True | |
@external | |
def mint(_to: address, _value: uint256): | |
""" | |
@dev Mint an amount of the token and assigns it to an account. | |
This encapsulates the modification of balances such that the | |
proper events are emitted. | |
@param _to The account that will receive the created tokens. | |
@param _value The amount that will be created. | |
""" | |
assert msg.sender == self.minter | |
assert _to != ZERO_ADDRESS | |
self.totalSupply += _value | |
self.balanceOf[_to] += _value | |
log Transfer(ZERO_ADDRESS, _to, _value) | |
@internal | |
def _burn(_to: address, _value: uint256): | |
""" | |
@dev Internal function that burns an amount of the token of a given | |
account. | |
@param _to The account whose tokens will be burned. | |
@param _value The amount that will be burned. | |
""" | |
assert _to != ZERO_ADDRESS | |
self.totalSupply -= _value | |
self.balanceOf[_to] -= _value | |
log Transfer(_to, ZERO_ADDRESS, _value) | |
@external | |
def burn(_value: uint256): | |
""" | |
@dev Burn an amount of the token of msg.sender. | |
@param _value The amount that will be burned. | |
""" | |
self._burn(msg.sender, _value) | |
@external | |
def burnFrom(_to: address, _value: uint256): | |
""" | |
@dev Burn an amount of the token from a given account. | |
@param _to The account whose tokens will be burned. | |
@param _value The amount that will be burned. | |
""" | |
self.allowance[_to][msg.sender] -= _value | |
self._burn(_to, _value) |