dynatrace-cordova-outsystems-plugin/node_modules/iconv-lite/encodings/utf16.js

This plugin gives you the ability to use the Dynatrace instrumentation in your hybrid application (Cordova, Ionic, ..). It uses the Mobile Agent, the JavaScript Agent and the Javascript Bridge. The Mobile Agent will give you all device specific values con

"use strict";
var Buffer = require("safer-buffer").Buffer;

// Note: UTF16-LE (or UCS2) codec is Node.js native. See encodings/internal.js

// == UTF16-BE codec. ==========================================================

exports.utf16be = Utf16BECodec;
function Utf16BECodec() {
}

Utf16BECodec.prototype.encoder = Utf16BEEncoder;
Utf16BECodec.prototype.decoder = Utf16BEDecoder;
Utf16BECodec.prototype.bomAware = true;


// -- Encoding

function Utf16BEEncoder() {
}

Utf16BEEncoder.prototype.write = function(str) {
    var buf = Buffer.from(str, 'ucs2');
    for (var i = 0; i < buf.length; i += 2) {
        var tmp = buf[i]; buf[i] = buf[i+1]; buf[i+1] = tmp;
    }
    return buf;
}

Utf16BEEncoder.prototype.end = function() {
}


// -- Decoding

function Utf16BEDecoder() {
    this.overflowByte = -1;
}

Utf16BEDecoder.prototype.write = function(buf) {
    if (buf.length == 0)
        return '';

    var buf2 = Buffer.alloc(buf.length + 1),
        i = 0, j = 0;

    if (this.overflowByte !== -1) {
        buf2[0] = buf[0];
        buf2[1] = this.overflowByte;
        i = 1; j = 2;
    }

    for (; i < buf.length-1; i += 2, j+= 2) {
        buf2[j] = buf[i+1];
        buf2[j+1] = buf[i];
    }

    this.overflowByte = (i == buf.length-1) ? buf[buf.length-1] : -1;

    return buf2.slice(0, j).toString('ucs2');
}

Utf16BEDecoder.prototype.end = function() {
}


// == UTF-16 codec =============================================================
// Decoder chooses automatically from UTF-16LE and UTF-16BE using BOM and space-based heuristic.
// Defaults to UTF-16LE, as it's prevalent and default in Node.
// http://en.wikipedia.org/wiki/UTF-16 and http://encoding.spec.whatwg.org/#utf-16le
// Decoder default can be changed: iconv.decode(buf, 'utf16', {defaultEncoding: 'utf-16be'});

// Encoder uses UTF-16LE and prepends BOM (which can be overridden with addBOM: false).

exports.utf16 = Utf16Codec;
function Utf16Codec(codecOptions, iconv) {
    this.iconv = iconv;
}

Utf16Codec.prototype.encoder = Utf16Encoder;
Utf16Codec.prototype.decoder = Utf16Decoder;


// -- Encoding (pass-through)

function Utf16Encoder(options, codec) {
    options = options || {};
    if (options.addBOM === undefined)
        options.addBOM = true;
    this.encoder = codec.iconv.getEncoder('utf-16le', options);
}

Utf16Encoder.prototype.write = function(str) {
    return this.encoder.write(str);
}

Utf16Encoder.prototype.end = function() {
    return this.encoder.end();
}


// -- Decoding

function Utf16Decoder(options, codec) {
    this.decoder = null;
    this.initialBytes = [];
    this.initialBytesLen = 0;

    this.options = options || {};
    this.iconv = codec.iconv;
}

Utf16Decoder.prototype.write = function(buf) {
    if (!this.decoder) {
        // Codec is not chosen yet. Accumulate initial bytes.
        this.initialBytes.push(buf);
        this.initialBytesLen += buf.length;
        
        if (this.initialBytesLen < 16) // We need more bytes to use space heuristic (see below)
            return '';

        // We have enough bytes -> detect endianness.
        var buf = Buffer.concat(this.initialBytes),
            encoding = detectEncoding(buf, this.options.defaultEncoding);
        this.decoder = this.iconv.getDecoder(encoding, this.options);
        this.initialBytes.length = this.initialBytesLen = 0;
    }

    return this.decoder.write(buf);
}

Utf16Decoder.prototype.end = function() {
    if (!this.decoder) {
        var buf = Buffer.concat(this.initialBytes),
            encoding = detectEncoding(buf, this.options.defaultEncoding);
        this.decoder = this.iconv.getDecoder(encoding, this.options);

        var res = this.decoder.write(buf),
            trail = this.decoder.end();

        return trail ? (res + trail) : res;
    }
    return this.decoder.end();
}

function detectEncoding(buf, defaultEncoding) {
    var enc = defaultEncoding || 'utf-16le';

    if (buf.length >= 2) {
        // Check BOM.
        if (buf[0] == 0xFE && buf[1] == 0xFF) // UTF-16BE BOM
            enc = 'utf-16be';
        else if (buf[0] == 0xFF && buf[1] == 0xFE) // UTF-16LE BOM
            enc = 'utf-16le';
        else {
            // No BOM found. Try to deduce encoding from initial content.
            // Most of the time, the content has ASCII chars (U+00**), but the opposite (U+**00) is uncommon.
            // So, we count ASCII as if it was LE or BE, and decide from that.
            var asciiCharsLE = 0, asciiCharsBE = 0, // Counts of chars in both positions
                _len = Math.min(buf.length - (buf.length % 2), 64); // Len is always even.

            for (var i = 0; i < _len; i += 2) {
                if (buf[i] === 0 && buf[i+1] !== 0) asciiCharsBE++;
                if (buf[i] !== 0 && buf[i+1] === 0) asciiCharsLE++;
            }

            if (asciiCharsBE > asciiCharsLE)
                enc = 'utf-16be';
            else if (asciiCharsBE < asciiCharsLE)
                enc = 'utf-16le';
        }
    }

    return enc;
}