// Detect It Easy: detection rule file format

init("installer", "Nullsoft Scriptable Install System");

function detect(bShowType, bShowVersion, bShowOptions) {
    var nOffset = PE.getOverlayOffset();
    if ((!PE.compareOverlay("EFBEADDE'Null'..'oftInst'", 4)) && (!PE.compareOverlay("EFBEADDE'nsisinstall'"))) {
        //        if(!PE.section[".ndata"])
        //        {
        //            return "";
        //        }
        if (PE.isOverlayPresent()) {
            nOffset += PE.readDword(nOffset);
            if (nOffset + 4 >= PE.getSize() || !PE.compare("EFBEADDE'Null'..'oftInst'", nOffset + 4)) {
                nOffset = 0;
            }
        }
    }
    if (nOffset && PE.isOverlayPresent()) {
        // Method detection adapted from 7-Zip.
        nOffset += 0x1C;
        if (PE.compare("5D0000..00", nOffset)) {
            sOptions = sOptions.append("lzma", "solid");
        } else if (PE.compare("5D0000....00", nOffset + 4)) {
            sOptions = sOptions.append("lzma");
        } else {
            function BorZ(nOffset) {
                if (PE.readByte(nOffset) == 0x31 && PE.readByte(nOffset + 1) < 14) {
                    return "bzip2";
                } else {
                    return "zlib";
                }
            }
            if (PE.compare("8", nOffset + 3)) {
                sOptions = sOptions.append(BorZ(nOffset + 4));
            } else {
                sOptions = sOptions.append(BorZ(nOffset), "solid");
            }
        }
        bDetected = true;
    }

    var aVersion = PE.getManifest().match(/Null[sS]oft Install System v?(.*?)</);
    if (aVersion) {
        sVersion = aVersion[1];
        bDetected = true;
    } else if (PE.compareEP("558BEC83EC2C535633F657568975DC8975F4BBA49E4000FF1560704000BFC0B24000")) {
        sVersion = "1.xx";
        bDetected = true;
    } else if (PE.compareEP("558BEC81EC....000056576A..BE........598DBD")) {
        sVersion = "1.3x";
        bDetected = true;
    } else if (PE.compareEP("83EC5C53555657FF15")) {
        sVersion = "1.x";
        bDetected = true;
    } else if (PE.compareEP("83EC0C535657FF15....40000")) {
        switch (PE.readWord(PE.nEP + 8)) {
            case 0x812C:
                sVersion = "1.98";
                break;
            case 0x10B4:
                sVersion = "2.0a0";
                break;
            default:
                sVersion = "1.xx";
        }
        bDetected = true;
    } else if (PE.compareEP("83EC0C53555657FF15..7040008B35..92400005E803000089442414B320FF152C704000")) {
        sVersion = "2.0b2/2.0b3";
        bDetected = true;
    } else if (PE.compareEP("83EC14836424040053555657C644241320FF1530704000BE00207A00")) {
        sVersion = "2.0b4";
        bDetected = true;
    } else if (PE.compareEP("83EC1053555657C7442414....400033EDC644241320FF152C704000")) {
        switch (PE.readWord(PE.nEP + 11)) {
            case 0x91F0:
                sVersion = "2.0b4";
                break;
            case 0x9270:
                sVersion = "2.0 RC2";
                break;
        }
        bDetected = true;
    } else if (PE.compareEP("83EC0C53555657C7442410........33DBC644241420FF15........53FF15")) {
        sVersion = "2.0";
        bDetected = true;
    } else if (PE.compareEP("83EC2053555633DB57895C2418C7442410........C644241420FF15")) {
        sVersion = "2.06";
        bDetected = true;
    } else if (PE.compareEP("558bec83ec..535633f657568975..8975..bb........ff15........bf........68........5750a3........ff15")) {
        sVersion = "0.98";
        bDetected = true;
    }

    return result(bShowType, bShowVersion, bShowOptions);
}