LibParseLiteral

Git Source

Functions

selectLiteralParserByIndex

function selectLiteralParserByIndex(ParseState memory state, uint256 index)
    internal
    pure
    returns (function(ParseState memory, uint256, uint256) pure returns (uint256));

boundLiteral

Find the bounds for some literal at the cursor. The caller is responsible for checking that the cursor is at the start of a literal and that the cursor is less than the end. As each literal type has a different format, this function returns the bounds for the literal and the type of the literal. The bounds are:

• innerStart: the start of the literal, e.g. after the 0x in 0x1234
• innerEnd: the end of the literal, e.g. after the 1234 in 0x1234
• outerEnd: the end of the literal including any suffixes, MAY be the same as innerEnd if there is no suffix. The outerStart is the cursor, so it is not returned.

function boundLiteral(ParseState memory state, uint256 cursor, uint256 end)
    internal
    pure
    returns (function(ParseState memory, uint256, uint256) pure returns (uint256), uint256, uint256, uint256);

Parameters

Returns

boundLiteralString

Find the bounds for some string literal at the cursor. The caller is responsible for checking that the cursor is at the start of a string literal. Bounds are as per boundLiteral.

function boundLiteralString(ParseState memory state, uint256 cursor, uint256 end)
    internal
    pure
    returns (function(ParseState memory, uint256, uint256) pure returns (uint256), uint256, uint256, uint256);

parseLiteralString

Algorithm for parsing string literals:

• Get the inner length of the string
• Mutate memory in place to add a length prefix, record the original data
• Use this solidity string to build an IntOrAString
• Restore the original data that the length prefix overwrote
• Return the IntOrAString

function parseLiteralString(ParseState memory, uint256 start, uint256 end) internal pure returns (uint256);

boundLiteralHex

function boundLiteralHex(ParseState memory state, uint256 cursor, uint256 end)
    internal
    pure
    returns (function(ParseState memory, uint256, uint256) pure returns (uint256), uint256, uint256, uint256);

boundLiteralHexAddress

Bounding a literal hex address is just a special case of bounding a literal hex. The only difference is that every address is the same known length as they are 160 bits (20 bytes). This means we need exactly 42 bytes between the start and end of the literal, including the 0x prefix, as each byte of a hex literal string = 0.5 bytes of encoded data.

function boundLiteralHexAddress(ParseState memory state, uint256 cursor, uint256 end)
    internal
    pure
    returns (
        function(ParseState memory, uint256, uint256) pure returns (uint256) parser,
        uint256 innerStart,
        uint256 innerEnd,
        uint256 outerEnd
    );

parseLiteralHex

Algorithm for parsing hexadecimal literals:

• start at the end of the literal
• for each character:
• convert the character to a nybble
• shift the nybble into the total at the correct position (4 bits per nybble)
• return the total

function parseLiteralHex(ParseState memory state, uint256 start, uint256 end) internal pure returns (uint256 value);

boundLiteralDecimal

function boundLiteralDecimal(ParseState memory state, uint256 cursor, uint256 end)
    internal
    pure
    returns (function(ParseState memory, uint256, uint256) pure returns (uint256), uint256, uint256, uint256);

parseLiteralDecimal

Algorithm for parsing decimal literals:

• start at the end of the literal
• for each digit:
• multiply the digit by 10^digit position
• add the result to the total
• return the total This algorithm is ONLY safe if the caller has already checked that the start/end span a non-zero length of valid decimal chars. The caller can most easily do this by using the boundLiteral function. Unsafe behavior is undefined and can easily result in out of bounds reads as there are no checks that start/end are within data.

function parseLiteralDecimal(ParseState memory state, uint256 start, uint256 end)
    internal
    pure
    returns (uint256 value);