File 11 of 15 : LibBytes.sol
// SPDX-License-Identifier: MIT
pragma solidity 0.8.17;
library LibBytes {
// solhint-disable no-inline-assembly
// LibBytes specific errors
error SliceOverflow();
error SliceOutOfBounds();
error AddressOutOfBounds();
error UintOutOfBounds();
// -------------------------
function concat(
bytes memory _preBytes,
bytes memory _postBytes
) internal pure returns (bytes memory) {
bytes memory tempBytes;
assembly {
// Get a location of some free memory and store it in tempBytes as
// Solidity does for memory variables.
tempBytes := mload(0x40)
// Store the length of the first bytes array at the beginning of
// the memory for tempBytes.
let length := mload(_preBytes)
mstore(tempBytes, length)
// Maintain a memory counter for the current write location in the
// temp bytes array by adding the 32 bytes for the array length to
// the starting location.
let mc := add(tempBytes, 0x20)
// Stop copying when the memory counter reaches the length of the
// first bytes array.
let end := add(mc, length)
for {
// Initialize a copy counter to the start of the _preBytes data,
// 32 bytes into its memory.
let cc := add(_preBytes, 0x20)
} lt(mc, end) {
// Increase both counters by 32 bytes each iteration.
mc := add(mc, 0x20)
cc := add(cc, 0x20)
} {
// Write the _preBytes data into the tempBytes memory 32 bytes
// at a time.
mstore(mc, mload(cc))
}
// Add the length of _postBytes to the current length of tempBytes
// and store it as the new length in the first 32 bytes of the
// tempBytes memory.
length := mload(_postBytes)
mstore(tempBytes, add(length, mload(tempBytes)))
// Move the memory counter back from a multiple of 0x20 to the
// actual end of the _preBytes data.
mc := end
// Stop copying when the memory counter reaches the new combined
// length of the arrays.
end := add(mc, length)
for {
let cc := add(_postBytes, 0x20)
} lt(mc, end) {
mc := add(mc, 0x20)
cc := add(cc, 0x20)
} {
mstore(mc, mload(cc))
}
// Update the free-memory pointer by padding our last write location
// to 32 bytes: add 31 bytes to the end of tempBytes to move to the
// next 32 byte block, then round down to the nearest multiple of
// 32. If the sum of the length of the two arrays is zero then add
// one before rounding down to leave a blank 32 bytes (the length block with 0).
mstore(
0x40,
and(
add(add(end, iszero(add(length, mload(_preBytes)))), 31),
not(31) // Round down to the nearest 32 bytes.
)
)
}
return tempBytes;
}
function concatStorage(
bytes storage _preBytes,
bytes memory _postBytes
) internal {
assembly {
// Read the first 32 bytes of _preBytes storage, which is the length
// of the array. (We don't need to use the offset into the slot
// because arrays use the entire slot.)
let fslot := sload(_preBytes.slot)
// Arrays of 31 bytes or less have an even value in their slot,
// while longer arrays have an odd value. The actual length is
// the slot divided by two for odd values, and the lowest order
// byte divided by two for even values.
// If the slot is even, bitwise and the slot with 255 and divide by
// two to get the length. If the slot is odd, bitwise and the slot
// with -1 and divide by two.
let slength := div(
and(fslot, sub(mul(0x100, iszero(and(fslot, 1))), 1)),
2
)
let mlength := mload(_postBytes)
let newlength := add(slength, mlength)
// slength can contain both the length and contents of the array
// if length < 32 bytes so let's prepare for that
// v. http://solidity.readthedocs.io/en/latest/miscellaneous.html#layout-of-state-variables-in-storage
switch add(lt(slength, 32), lt(newlength, 32))
case 2 {
// Since the new array still fits in the slot, we just need to
// update the contents of the slot.
// uint256(bytes_storage) = uint256(bytes_storage) + uint256(bytes_memory) + new_length
sstore(
_preBytes.slot,
// all the modifications to the slot are inside this
// next block
add(
// we can just add to the slot contents because the
// bytes we want to change are the LSBs
fslot,
add(
mul(
div(
// load the bytes from memory
mload(add(_postBytes, 0x20)),
// zero all bytes to the right
exp(0x100, sub(32, mlength))
),
// and now shift left the number of bytes to
// leave space for the length in the slot
exp(0x100, sub(32, newlength))
),
// increase length by the double of the memory
// bytes length
mul(mlength, 2)
)
)
)
}
case 1 {
// The stored value fits in the slot, but the combined value
// will exceed it.
// get the keccak hash to get the contents of the array
mstore(0x0, _preBytes.slot)
let sc := add(keccak256(0x0, 0x20), div(slength, 32))
// save new length
sstore(_preBytes.slot, add(mul(newlength, 2), 1))
// The contents of the _postBytes array start 32 bytes into
// the structure. Our first read should obtain the `submod`
// bytes that can fit into the unused space in the last word
// of the stored array. To get this, we read 32 bytes starting
// from `submod`, so the data we read overlaps with the array
// contents by `submod` bytes. Masking the lowest-order
// `submod` bytes allows us to add that value directly to the
// stored value.
let submod := sub(32, slength)
let mc := add(_postBytes, submod)
let end := add(_postBytes, mlength)
let mask := sub(exp(0x100, submod), 1)
sstore(
sc,
add(
and(
fslot,
0xffffffffffffffffffffffffffffffffffffffffffffffffffffffffffffff00
),
and(mload(mc), mask)
)
)
for {
mc := add(mc, 0x20)
sc := add(sc, 1)
} lt(mc, end) {
sc := add(sc, 1)
mc := add(mc, 0x20)
} {
sstore(sc, mload(mc))
}
mask := exp(0x100, sub(mc, end))
sstore(sc, mul(div(mload(mc), mask), mask))
}
default {
// get the keccak hash to get the contents of the array
mstore(0x0, _preBytes.slot)
// Start copying to the last used word of the stored array.
let sc := add(keccak256(0x0, 0x20), div(slength, 32))
// save new length
sstore(_preBytes.slot, add(mul(newlength, 2), 1))
// Copy over the first `submod` bytes of the new data as in
// case 1 above.
let slengthmod := mod(slength, 32)
let submod := sub(32, slengthmod)
let mc := add(_postBytes, submod)
let end := add(_postBytes, mlength)
let mask := sub(exp(0x100, submod), 1)
sstore(sc, add(sload(sc), and(mload(mc), mask)))
for {
sc := add(sc, 1)
mc := add(mc, 0x20)
} lt(mc, end) {
sc := add(sc, 1)
mc := add(mc, 0x20)
} {
sstore(sc, mload(mc))
}
mask := exp(0x100, sub(mc, end))
sstore(sc, mul(div(mload(mc), mask), mask))
}
}
}
function slice(
bytes memory _bytes,
uint256 _start,
uint256 _length
) internal pure returns (bytes memory) {
if (_length + 31 < _length) revert SliceOverflow();
if (_bytes.length < _start + _length) revert SliceOutOfBounds();
bytes memory tempBytes;
assembly {
switch iszero(_length)
case 0 {
// Get a location of some free memory and store it in tempBytes as
// Solidity does for memory variables.
tempBytes := mload(0x40)
// The first word of the slice result is potentially a partial
// word read from the original array. To read it, we calculate
// the length of that partial word and start copying that many
// bytes into the array. The first word we copy will start with
// data we don't care about, but the last `lengthmod` bytes will
// land at the beginning of the contents of the new array. When
// we're done copying, we overwrite the full first word with
// the actual length of the slice.
let lengthmod := and(_length, 31)
// The multiplication in the next line is necessary
// because when slicing multiples of 32 bytes (lengthmod == 0)
// the following copy loop was copying the origin's length
// and then ending prematurely not copying everything it should.
let mc := add(
add(tempBytes, lengthmod),
mul(0x20, iszero(lengthmod))
)
let end := add(mc, _length)
for {
// The multiplication in the next line has the same exact purpose
// as the one above.
let cc := add(
add(
add(_bytes, lengthmod),
mul(0x20, iszero(lengthmod))
),
_start
)
} lt(mc, end) {
mc := add(mc, 0x20)
cc := add(cc, 0x20)
} {
mstore(mc, mload(cc))
}
mstore(tempBytes, _length)
//update free-memory pointer
//allocating the array padded to 32 bytes like the compiler does now
mstore(0x40, and(add(mc, 31), not(31)))
}
//if we want a zero-length slice let's just return a zero-length array
default {
tempBytes := mload(0x40)
//zero out the 32 bytes slice we are about to return
//we need to do it because Solidity does not garbage collect
mstore(tempBytes, 0)
mstore(0x40, add(tempBytes, 0x20))
}
}
return tempBytes;
}
function toAddress(
bytes memory _bytes,
uint256 _start
) internal pure returns (address) {
if (_bytes.length < _start + 20) {
revert AddressOutOfBounds();
}
address tempAddress;
assembly {
tempAddress := div(
mload(add(add(_bytes, 0x20), _start)),
0x1000000000000000000000000
)
}
return tempAddress;
}
function toUint8(
bytes memory _bytes,
uint256 _start
) internal pure returns (uint8) {
if (_bytes.length < _start + 1) {
revert UintOutOfBounds();
}
uint8 tempUint;
assembly {
tempUint := mload(add(add(_bytes, 0x1), _start))
}
return tempUint;
}
function toUint16(
bytes memory _bytes,
uint256 _start
) internal pure returns (uint16) {
if (_bytes.length < _start + 2) {
revert UintOutOfBounds();
}
uint16 tempUint;
assembly {
tempUint := mload(add(add(_bytes, 0x2), _start))
}
return tempUint;
}
function toUint32(
bytes memory _bytes,
uint256 _start
) internal pure returns (uint32) {
if (_bytes.length < _start + 4) {
revert UintOutOfBounds();
}
uint32 tempUint;
assembly {
tempUint := mload(add(add(_bytes, 0x4), _start))
}
return tempUint;
}
function toUint64(
bytes memory _bytes,
uint256 _start
) internal pure returns (uint64) {
if (_bytes.length < _start + 8) {
revert UintOutOfBounds();
}
uint64 tempUint;
assembly {
tempUint := mload(add(add(_bytes, 0x8), _start))
}
return tempUint;
}
function toUint96(
bytes memory _bytes,
uint256 _start
) internal pure returns (uint96) {
if (_bytes.length < _start + 12) {
revert UintOutOfBounds();
}
uint96 tempUint;
assembly {
tempUint := mload(add(add(_bytes, 0xc), _start))
}
return tempUint;
}
function toUint128(
bytes memory _bytes,
uint256 _start
) internal pure returns (uint128) {
if (_bytes.length < _start + 16) {
revert UintOutOfBounds();
}
uint128 tempUint;
assembly {
tempUint := mload(add(add(_bytes, 0x10), _start))
}
return tempUint;
}
function toUint256(
bytes memory _bytes,
uint256 _start
) internal pure returns (uint256) {
if (_bytes.length < _start + 32) {
revert UintOutOfBounds();
}
uint256 tempUint;
assembly {
tempUint := mload(add(add(_bytes, 0x20), _start))
}
return tempUint;
}
function toBytes32(
bytes memory _bytes,
uint256 _start
) internal pure returns (bytes32) {
if (_bytes.length < _start + 32) {
revert UintOutOfBounds();
}
bytes32 tempBytes32;
assembly {
tempBytes32 := mload(add(add(_bytes, 0x20), _start))
}
return tempBytes32;
}
function equal(
bytes memory _preBytes,
bytes memory _postBytes
) internal pure returns (bool) {
bool success = true;
assembly {
let length := mload(_preBytes)
// if lengths don't match the arrays are not equal
switch eq(length, mload(_postBytes))
case 1 {
// cb is a circuit breaker in the for loop since there's
// no said feature for inline assembly loops
// cb = 1 - don't breaker
// cb = 0 - break
let cb := 1
let mc := add(_preBytes, 0x20)
let end := add(mc, length)
for {
let cc := add(_postBytes, 0x20)
// the next line is the loop condition:
// while(uint256(mc < end) + cb == 2)
} eq(add(lt(mc, end), cb), 2) {
mc := add(mc, 0x20)
cc := add(cc, 0x20)
} {
// if any of these checks fails then arrays are not equal
if iszero(eq(mload(mc), mload(cc))) {
// unsuccess:
success := 0
cb := 0
}
}
}
default {
// unsuccess:
success := 0
}
}
return success;
}
function equalStorage(
bytes storage _preBytes,
bytes memory _postBytes
) internal view returns (bool) {
bool success = true;
assembly {
// we know _preBytes_offset is 0
let fslot := sload(_preBytes.slot)
// Decode the length of the stored array like in concatStorage().
let slength := div(
and(fslot, sub(mul(0x100, iszero(and(fslot, 1))), 1)),
2
)
let mlength := mload(_postBytes)
// if lengths don't match the arrays are not equal
switch eq(slength, mlength)
case 1 {
// slength can contain both the length and contents of the array
// if length < 32 bytes so let's prepare for that
// v. http://solidity.readthedocs.io/en/latest/miscellaneous.html#layout-of-state-variables-in-storage
if iszero(iszero(slength)) {
switch lt(slength, 32)
case 1 {
// blank the last byte which is the length
fslot := mul(div(fslot, 0x100), 0x100)
if iszero(eq(fslot, mload(add(_postBytes, 0x20)))) {
// unsuccess:
success := 0
}
}
default {
// cb is a circuit breaker in the for loop since there's
// no said feature for inline assembly loops
// cb = 1 - don't breaker
// cb = 0 - break
let cb := 1
// get the keccak hash to get the contents of the array
mstore(0x0, _preBytes.slot)
let sc := keccak256(0x0, 0x20)
let mc := add(_postBytes, 0x20)
let end := add(mc, mlength)
// the next line is the loop condition:
// while(uint256(mc < end) + cb == 2)
// solhint-disable-next-line no-empty-blocks
for {
} eq(add(lt(mc, end), cb), 2) {
sc := add(sc, 1)
mc := add(mc, 0x20)
} {
if iszero(eq(sload(sc), mload(mc))) {
// unsuccess:
success := 0
cb := 0
}
}
}
}
}
default {
// unsuccess:
success := 0
}
}
return success;
}
function getFirst4Bytes(
bytes memory data
) internal pure returns (bytes4 outBytes4) {
if (data.length == 0) {
return 0x0;
}
assembly {
outBytes4 := mload(add(data, 32))
}
}
}
APIs
Contract Source Code Verified 
