sc4/lib/core/dir.js

A command line utility for automating SimCity 4 modding tasks & modifying savegames

import { FileType } from './enums.js';
import { kFileType } from './symbols.js';
import WriteBuffer from './write-buffer.js';
// # DIR
// A class representing a DatabaseDirectoryFile, more commonly known as a DIR 
// record.
export default class DIR extends Array {
    static [kFileType] = FileType.DIR;
    // ## parse(rs, opts)
    parse(rs, opts = {}) {
        // In DBPF 7.1, DIR records have a length of 20 bytes. This is normally 
        // not used in SimCity 4, but we still support it though.
        let { entry = null } = opts;
        let major = entry?.dbpf?.header.indexMajor ?? 7;
        let minor = entry?.dbpf?.header.indexMinor ?? 0;
        let shouldSkip = major === 7 && minor > 1;
        // Reset our length and then read in the entire DIR record.
        this.length = 0;
        while (rs.remaining() > 0) {
            let tgi = rs.tgi();
            let size = rs.uint32();
            if (shouldSkip)
                rs.skip(4);
            this.push({ tgi, size });
        }
        return this;
    }
    // ## toBuffer(opts)
    toBuffer(opts = {}) {
        let { major = 7, minor = 0 } = opts;
        let byteLength = major === 7 && minor > 1 ? 20 : 16;
        let ws = new WriteBuffer({ size: this.length * byteLength });
        for (let row of this) {
            ws.tgi(row.tgi);
            ws.uint32(row.size);
            if (byteLength === 20)
                ws.uint32(0);
        }
        return ws.toUint8Array();
    }
}