luhn-generator
Version:
A generator of numbers that passes the validation of Luhn algorithm or Luhn formula, also known as the 'modulus 10' or 'mod 10' algorithm
218 lines (174 loc) • 8.7 kB
JavaScript
;
var Buffer = require("buffer").Buffer;
// Note: not polyfilled with safer-buffer on a purpose, as overrides Buffer
// == Extend Node primitives to use iconv-lite =================================
module.exports = function (iconv) {
var original = undefined; // Place to keep original methods.
// Node authors rewrote Buffer internals to make it compatible with
// Uint8Array and we cannot patch key functions since then.
// Note: this does use older Buffer API on a purpose
iconv.supportsNodeEncodingsExtension = !(Buffer.from || new Buffer(0) instanceof Uint8Array);
iconv.extendNodeEncodings = function extendNodeEncodings() {
if (original) return;
original = {};
if (!iconv.supportsNodeEncodingsExtension) {
console.error("ACTION NEEDED: require('iconv-lite').extendNodeEncodings() is not supported in your version of Node");
console.error("See more info at https://github.com/ashtuchkin/iconv-lite/wiki/Node-v4-compatibility");
return;
}
var nodeNativeEncodings = {
'hex': true, 'utf8': true, 'utf-8': true, 'ascii': true, 'binary': true,
'base64': true, 'ucs2': true, 'ucs-2': true, 'utf16le': true, 'utf-16le': true,
};
Buffer.isNativeEncoding = function(enc) {
return enc && nodeNativeEncodings[enc.toLowerCase()];
}
// -- SlowBuffer -----------------------------------------------------------
var SlowBuffer = require('buffer').SlowBuffer;
original.SlowBufferToString = SlowBuffer.prototype.toString;
SlowBuffer.prototype.toString = function(encoding, start, end) {
encoding = String(encoding || 'utf8').toLowerCase();
// Use native conversion when possible
if (Buffer.isNativeEncoding(encoding))
return original.SlowBufferToString.call(this, encoding, start, end);
// Otherwise, use our decoding method.
if (typeof start == 'undefined') start = 0;
if (typeof end == 'undefined') end = this.length;
return iconv.decode(this.slice(start, end), encoding);
}
original.SlowBufferWrite = SlowBuffer.prototype.write;
SlowBuffer.prototype.write = function(string, offset, length, encoding) {
// Support both (string, offset, length, encoding)
// and the legacy (string, encoding, offset, length)
if (isFinite(offset)) {
if (!isFinite(length)) {
encoding = length;
length = undefined;
}
} else { // legacy
var swap = encoding;
encoding = offset;
offset = length;
length = swap;
}
offset = +offset || 0;
var remaining = this.length - offset;
if (!length) {
length = remaining;
} else {
length = +length;
if (length > remaining) {
length = remaining;
}
}
encoding = String(encoding || 'utf8').toLowerCase();
// Use native conversion when possible
if (Buffer.isNativeEncoding(encoding))
return original.SlowBufferWrite.call(this, string, offset, length, encoding);
if (string.length > 0 && (length < 0 || offset < 0))
throw new RangeError('attempt to write beyond buffer bounds');
// Otherwise, use our encoding method.
var buf = iconv.encode(string, encoding);
if (buf.length < length) length = buf.length;
buf.copy(this, offset, 0, length);
return length;
}
// -- Buffer ---------------------------------------------------------------
original.BufferIsEncoding = Buffer.isEncoding;
Buffer.isEncoding = function(encoding) {
return Buffer.isNativeEncoding(encoding) || iconv.encodingExists(encoding);
}
original.BufferByteLength = Buffer.byteLength;
Buffer.byteLength = SlowBuffer.byteLength = function(str, encoding) {
encoding = String(encoding || 'utf8').toLowerCase();
// Use native conversion when possible
if (Buffer.isNativeEncoding(encoding))
return original.BufferByteLength.call(this, str, encoding);
// Slow, I know, but we don't have a better way yet.
return iconv.encode(str, encoding).length;
}
original.BufferToString = Buffer.prototype.toString;
Buffer.prototype.toString = function(encoding, start, end) {
encoding = String(encoding || 'utf8').toLowerCase();
// Use native conversion when possible
if (Buffer.isNativeEncoding(encoding))
return original.BufferToString.call(this, encoding, start, end);
// Otherwise, use our decoding method.
if (typeof start == 'undefined') start = 0;
if (typeof end == 'undefined') end = this.length;
return iconv.decode(this.slice(start, end), encoding);
}
original.BufferWrite = Buffer.prototype.write;
Buffer.prototype.write = function(string, offset, length, encoding) {
var _offset = offset, _length = length, _encoding = encoding;
// Support both (string, offset, length, encoding)
// and the legacy (string, encoding, offset, length)
if (isFinite(offset)) {
if (!isFinite(length)) {
encoding = length;
length = undefined;
}
} else { // legacy
var swap = encoding;
encoding = offset;
offset = length;
length = swap;
}
encoding = String(encoding || 'utf8').toLowerCase();
// Use native conversion when possible
if (Buffer.isNativeEncoding(encoding))
return original.BufferWrite.call(this, string, _offset, _length, _encoding);
offset = +offset || 0;
var remaining = this.length - offset;
if (!length) {
length = remaining;
} else {
length = +length;
if (length > remaining) {
length = remaining;
}
}
if (string.length > 0 && (length < 0 || offset < 0))
throw new RangeError('attempt to write beyond buffer bounds');
// Otherwise, use our encoding method.
var buf = iconv.encode(string, encoding);
if (buf.length < length) length = buf.length;
buf.copy(this, offset, 0, length);
return length;
// TODO: Set _charsWritten.
}
// -- Readable -------------------------------------------------------------
if (iconv.supportsStreams) {
var Readable = require('stream').Readable;
original.ReadableSetEncoding = Readable.prototype.setEncoding;
Readable.prototype.setEncoding = function setEncoding(enc, options) {
// Use our own decoder, it has the same interface.
// We cannot use original function as it doesn't handle BOM-s.
this._readableState.decoder = iconv.getDecoder(enc, options);
this._readableState.encoding = enc;
}
Readable.prototype.collect = iconv._collect;
}
}
// Remove iconv-lite Node primitive extensions.
iconv.undoExtendNodeEncodings = function undoExtendNodeEncodings() {
if (!iconv.supportsNodeEncodingsExtension)
return;
if (!original)
throw new Error("require('iconv-lite').undoExtendNodeEncodings(): Nothing to undo; extendNodeEncodings() is not called.")
delete Buffer.isNativeEncoding;
var SlowBuffer = require('buffer').SlowBuffer;
SlowBuffer.prototype.toString = original.SlowBufferToString;
SlowBuffer.prototype.write = original.SlowBufferWrite;
Buffer.isEncoding = original.BufferIsEncoding;
Buffer.byteLength = original.BufferByteLength;
Buffer.prototype.toString = original.BufferToString;
Buffer.prototype.write = original.BufferWrite;
if (iconv.supportsStreams) {
var Readable = require('stream').Readable;
Readable.prototype.setEncoding = original.ReadableSetEncoding;
delete Readable.prototype.collect;
}
original = undefined;
}
}