ethers.js/packages/abi/src.ts/coders/array.ts

"use strict";

import * as errors from "@ethersproject/errors";

import { Coder, Reader, Writer } from "./abstract-coder";
import { AnonymousCoder } from "./anonymous";

export function pack(writer: Writer, coders: Array<Coder>, values: Array<any>): number {

    if (Array.isArray(values)) {
       // do nothing

    } else if (values && typeof(values) === "object") {
        let arrayValues: Array<any> = [];
        coders.forEach(function(coder) {
            arrayValues.push((<any>values)[coder.localName]);
        });
        values = arrayValues;

    } else {
        errors.throwError("invalid tuple value", errors.INVALID_ARGUMENT, {
            coderType: "tuple",
            value: values
        });
    }

    if (coders.length !== values.length) {
        errors.throwError("types/value length mismatch", errors.INVALID_ARGUMENT, {
            coderType: "tuple",
            value: values
        });
    }

    let staticWriter = new Writer(writer.wordSize);
    let dynamicWriter = new Writer(writer.wordSize);

    let updateFuncs: Array<(baseOffset: number) => void> = [];
    coders.forEach((coder, index) => {
        let value = values[index];

        if (coder.dynamic) {
            // Get current dynamic offset (for the future pointer)
            let dynamicOffset = dynamicWriter.length;

            // Encode the dynamic value into the dynamicWriter
            coder.encode(dynamicWriter, value);

            // Prepare to populate the correct offset once we are done
            let updateFunc = staticWriter.writeUpdatableValue();
            updateFuncs.push((baseOffset: number) => {
                updateFunc(baseOffset + dynamicOffset);
            });

        } else {
            coder.encode(staticWriter, value);
        }
    });

    // Backfill all the dynamic offsets, now that we know the static length
    updateFuncs.forEach((func) => { func(staticWriter.length); });

    let length = writer.writeBytes(staticWriter.data);
    length += writer.writeBytes(dynamicWriter.data);
    return length;
}

export function unpack(reader: Reader, coders: Array<Coder>): Array<any> {
    let values: any = [];

    // A reader anchored to this base
    let baseReader = reader.subReader(0);

    // The amount of dynamic data read; to consume later to synchronize
    let dynamicLength = 0;

    coders.forEach((coder) => {
        let value: any = null;

        if (coder.dynamic) {
            let offset = reader.readValue();
            let offsetReader = baseReader.subReader(offset.toNumber());
            value = coder.decode(offsetReader);
            dynamicLength += offsetReader.consumed;
        } else {
            value = coder.decode(reader);
        }

        if (value != undefined) {
            values.push(value);
        }
    });

// @TODO: get rid of this an see if it still works?
    // Consume the dynamic components in the main reader
    reader.readBytes(dynamicLength);

    // Add any named parameters (i.e. tuples)
    coders.forEach((coder: Coder, index: number) => {
        let name: string = coder.localName;
        if (!name) { return; }

        if (name === "length") { name = "_length"; }

        if (values[name] != null) { return; }

        values[name] = values[index];
    });

    return values;
}


export class ArrayCoder extends Coder {
    readonly coder: Coder;
    readonly length: number;

    constructor(coder: Coder, length: number, localName: string) {
        const type = (coder.type + "[" + (length >= 0 ? length: "") + "]");
        const dynamic = (length === -1 || coder.dynamic);
        super("array", type, localName, dynamic);

        this.coder = coder;
        this.length = length;
    }

    encode(writer: Writer, value: Array<any>): number {
        if (!Array.isArray(value)) {
            this._throwError("expected array value", value);
        }

        let count = this.length;

        //let result = new Uint8Array(0);
        if (count === -1) {
            count = value.length;
            writer.writeValue(value.length);
        }

        errors.checkArgumentCount(count, value.length, " in coder array" + (this.localName? (" "+ this.localName): ""));

        let coders = [];
        for (let i = 0; i < value.length; i++) { coders.push(this.coder); }

        return pack(writer, coders, value);
    }

    decode(reader: Reader): any {
        let count = this.length;
        if (count === -1) {
            count = reader.readValue().toNumber();
        }

        let coders = [];
        for (let i = 0; i < count; i++) { coders.push(new AnonymousCoder(this.coder)); }

        return reader.coerce(this.name, unpack(reader, coders));
    }
}