packages/codec/lib/memory/allocate/index.ts
import debugModule from "debug";
const debug = debugModule("codec:memory:allocate");
import type {
MemoryAllocations,
MemoryAllocation,
MemoryMemberAllocation
} from "./types";
import * as Evm from "@truffle/codec/evm";
import type * as Format from "@truffle/codec/format";
export { MemoryAllocations, MemoryAllocation, MemoryMemberAllocation };
export function getMemoryAllocations(
userDefinedTypes: Format.Types.TypesById
): MemoryAllocations {
let allocations: MemoryAllocations = {};
for (const dataType of Object.values(userDefinedTypes)) {
if (dataType.typeClass === "struct") {
allocations[dataType.id] = allocateStruct(dataType);
}
}
return allocations;
}
export function isSkippedInMemoryStructs(dataType: Format.Types.Type): boolean {
if (dataType.typeClass === "mapping") {
return true;
} else if (dataType.typeClass === "array") {
return isSkippedInMemoryStructs(dataType.baseType);
} else {
return false;
}
}
//unlike in storage and calldata, we'll just return the one allocation, nothing fancy
//that's because allocating one struct can never necessitate allocating another
function allocateStruct(dataType: Format.Types.StructType): MemoryAllocation {
let memberAllocations: MemoryMemberAllocation[] = [];
let position = 0;
for (const { name, type: memberType } of dataType.memberTypes) {
const length = isSkippedInMemoryStructs(memberType)
? 0
: Evm.Utils.WORD_SIZE;
memberAllocations.push({
name,
type: memberType,
pointer: {
location: "memory",
start: position,
length
}
});
position += length;
}
return {
members: memberAllocations
};
}