Method copyByteArrayToStorageFunction

libsolidity/codegen/YulUtilFunctions.cpp:2063–2138

std::string YulUtilFunctions::copyByteArrayToStorageFunction(ArrayType const& _fromType, ArrayType const& _toType)
{
	solAssert(
		(*_fromType.copyForLocation(_toType.location(), _toType.isPointer())).equals(dynamic_cast<ReferenceType const&>(_toType)),
		""
	);
	solAssert(_fromType.isByteArrayOrString(), "");
	solAssert(_toType.isByteArrayOrString(), "");

	std::string functionName = "copy_byte_array_to_storage_from_" + _fromType.identifier() + "_to_" + _toType.identifier();
	return m_functionCollector.createFunction(functionName, [&](){
		Whiskers templ(R"(
			function <functionName>(slot, src<?fromCalldata>, len</fromCalldata>) {
				<?fromStorage> if eq(slot, src) { leave } </fromStorage>

				let newLen := <arrayLength>(src<?fromCalldata>, len</fromCalldata>)
				// Make sure array length is sane
				if gt(newLen, 0xffffffffffffffff) { <panic>() }

				let oldLen := <byteArrayLength>(sload(slot))

				// potentially truncate data
				<cleanUpEndArray>(slot, oldLen, newLen)

				let srcOffset := 0
				<?fromMemory>
					srcOffset := 0x20
				</fromMemory>

				switch gt(newLen, 31)
				case 1 {
					let loopEnd := and(newLen, not(0x1f))
					<?fromStorage> src := <srcDataLocation>(src) </fromStorage>
					let dstPtr := <dstDataLocation>(slot)
					let i := 0
					for { } lt(i, loopEnd) { i := add(i, 0x20) } {
						sstore(dstPtr, <read>(add(src, srcOffset)))
						dstPtr := add(dstPtr, 1)
						srcOffset := add(srcOffset, <srcIncrement>)
					}
					if lt(loopEnd, newLen) {
						let lastValue := <read>(add(src, srcOffset))
						sstore(dstPtr, <maskBytes>(lastValue, and(newLen, 0x1f)))
					}
					sstore(slot, add(mul(newLen, 2), 1))
				}
				default {
					let value := 0
					if newLen {
						value := <read>(add(src, srcOffset))
					}
					sstore(slot, <byteArrayCombineShort>(value, newLen))
				}
			}
		)");
		templ("functionName", functionName);
		bool fromStorage = _fromType.dataStoredIn(DataLocation::Storage);
		templ("fromStorage", fromStorage);