index.js

"use strict";
exports.__esModule = true;
var fs = require("fs");
exports["default"] = getTargetArch;
// DWORD for offset of PE signature; see
// https://docs.microsoft.com/en-us/windows/win32/debug/pe-format#ms-dos-stub-image-only
var SIGNATURE_OFFSET_OFFSET = 0x3c;
function getTargetArch(path, callback) {
    fs.open(path, "r", function (err, fd) {
        if (err)
            return callback(err);
        readMagic(fd, function (err, archName, archCode) {
            fs.close(fd, function (closeErr) {
                if (closeErr !== null && closeErr !== void 0 ? closeErr : err)
                    return callback(closeErr !== null && closeErr !== void 0 ? closeErr : err);
                else
                    callback(null, archName, archCode);
            });
        });
    });
}
function readMagic(fd, callback) {
    var buffer = Buffer.alloc(4);
    fs.read(fd, buffer, 0, 2, 0, function (err, bytesRead) {
        if (err)
            return callback(err);
        if (bytesRead !== 2)
            return callback(new Error("failed to read MZ magic"));
        var magic = buffer.readInt16BE();
        var bigEndian = null;
        if (magic === 0x5a4d)
            bigEndian = true;
        else if (magic === 0x4d5a)
            bigEndian = false;
        else
            return callback(new Error("not a DOS-MZ file"));
        readTargetArch(fd, bigEndian, callback);
    });
}
function readTargetArch(fd, bigEndian, callback) {
    var buffer = Buffer.alloc(4);
    fs.read(fd, buffer, 0, 4, SIGNATURE_OFFSET_OFFSET, function (err, bytesRead) {
        if (err)
            return callback(err);
        if (bytesRead !== 4)
            return callback(new Error("failed to read PE signature offset"));
        var signatureOffset = bigEndian
            ? buffer.readUInt32BE()
            : buffer.readUInt32LE();
        var targetArchOffset = signatureOffset + 4;
        fs.read(fd, buffer, 0, 2, targetArchOffset, function (err, bytesRead) {
            if (err)
                return callback(err);
            if (bytesRead !== 2)
                return callback(new Error("failed to read PE architecture field"));
            var targetArchCode = bigEndian
                ? buffer.readUInt16BE()
                : buffer.readUInt16LE();
            var targetArchName = architectureNameByCode(targetArchCode);
            callback(null, targetArchName, targetArchCode);
        });
    });
}
// see https://docs.microsoft.com/en-us/windows/win32/debug/pe-format#machine-types
function architectureNameByCode(code) {
    switch (code) {
        case 0x0:
            return "UNKNOWN";
        case 0x1d3:
            return "AM33";
        case 0x8664:
            return "AMD64";
        case 0x1c0:
            return "ARM";
        case 0xaa64:
            return "ARM64";
        case 0x1c4:
            return "ARMNT";
        case 0xebc:
            return "EBC";
        case 0x14c:
            return "I386";
        case 0x200:
            return "IA64";
        case 0x9041:
            return "M32R";
        case 0x266:
            return "MIPS16";
        case 0x366:
            return "MIPSFPU";
        case 0x466:
            return "MIPSFPU16";
        case 0x1f0:
            return "POWERPC";
        case 0x1f1:
            return "POWERPCFP";
        case 0x166:
            return "R4000";
        case 0x5032:
            return "RISCV32";
        case 0x5064:
            return "RISCV64";
        case 0x5128:
            return "RISCV128";
        case 0x1a2:
            return "SH3";
        case 0x1a3:
            return "SH3DSP";
        case 0x1a6:
            return "SH4";
        case 0x1a8:
            return "SH5";
        case 0x1c2:
            return "THUMB";
        case 0x169:
            return "WCEMIPSV2";
        default:
            return null;
    }
}