371 lines
13 KiB
JavaScript
371 lines
13 KiB
JavaScript
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var SmartBuffer = (function () {
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/**
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* Constructor for SmartBuffer.
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* @param arg1 {Buffer || Number || String} Buffer to read from, or expected size to write to, or encoding to use.
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* @param arg2 {String} Encoding to use for writing and reading strings. Defaults to utf8. If encoding is given in arg1, this is ignored.
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* @constructor
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*
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* There are a few ways to construct a SmartBuffer:
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*
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* SmartBuffer() - Defaults to utf8, 4096 pre-set internal Buffer length.
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* SmartBuffer(size) - Defaults to utf8, sets internal Buffer length to the size given.
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* SmartBuffer(encoding) - Sets the given encoding, defaults to 4096 pre-set internal Buffer length.
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* SmartBuffer(Buffer) - Defaults to utf8, sets the internal Buffer to the given buffer (same memory).
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* SmartBuffer(Buffer, encoding) - Sets the given encoding, sets the internal Buffer to the given buffer (same memory).
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*
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*/
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function SmartBuffer(arg1, arg2) {
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var type;
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switch (type = typeof arg1) {
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case 'number':
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if (isFinite(arg1) && arg1 > 0) {
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this.buff = new Buffer(Math.ceil(arg1));
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this.length = 0;
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} else {
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throw new Error('When specifying a size, it must be a valid number above zero.');
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}
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break;
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case 'string':
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if (Buffer.isEncoding(arg1)) {
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this.buff = new Buffer(4096);
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this.length = 0;
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this.encoding = arg1;
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} else {
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throw new Error('Invalid Encoding');
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}
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break;
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case 'object':
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if (Buffer.isBuffer(arg1)) {
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this.buff = arg1;
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this.length = arg1.length;
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} else {
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throw new TypeError('First argument must be a Buffer, Number representing the size, or a String representing the encoding.');
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}
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break;
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default:
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this.buff = new Buffer(4096);
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this.length = 0;
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break;
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}
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if (typeof this.encoding === 'undefined') {
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if (typeof arg2 === 'string') {
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if (Buffer.isEncoding(arg2)) {
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this.encoding = arg2;
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} else {
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throw new Error('Invalid Encoding');
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}
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}
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}
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this._readOffset = 0;
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this._writeOffset = 0;
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}
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SmartBuffer.prototype._ensureWritable = function (len, offset) {
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this._ensureCapacity(this.length + len + (typeof offset === 'number' ? offset : 0));
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if (typeof offset === 'number') {
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this.buff.copy(this.buff, offset + len, offset, this.buff.length);
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}
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this.length = Math.max(this.length + len, (typeof offset === 'number' ? offset : 0) + len);
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};
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SmartBuffer.prototype._ensureCapacity = function (minlen) {
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var oldlen = this.buff.length;
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if (minlen > oldlen) {
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var data = this.buff;
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var newlen = (oldlen * 3) / 2 + 1;
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if (newlen < minlen)
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newlen = minlen;
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this.buff = new Buffer(newlen);
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data.copy(this.buff, 0, 0, oldlen);
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}
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};
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var makeReader = function (func, size) {
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return function () {
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var ret = func.call(this.buff, this._readOffset);
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this._readOffset += size;
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return ret;
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}
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};
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var makeWriter = function (func, size) {
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return function (value, offset) {
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this._ensureWritable(size, offset);
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func.call(this.buff, value, typeof offset === 'number' ? offset : this._writeOffset);
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this._writeOffset += size;
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return this;
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}
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};
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/*
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Read Operations
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*/
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SmartBuffer.prototype.readInt8 = makeReader(Buffer.prototype.readInt8, 1);
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SmartBuffer.prototype.readInt16BE = makeReader(Buffer.prototype.readInt16BE, 2);
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SmartBuffer.prototype.readInt16LE = makeReader(Buffer.prototype.readInt16LE, 2);
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SmartBuffer.prototype.readInt32BE = makeReader(Buffer.prototype.readInt32BE, 4);
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SmartBuffer.prototype.readInt32LE = makeReader(Buffer.prototype.readInt32LE, 4);
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SmartBuffer.prototype.readUInt8 = makeReader(Buffer.prototype.readUInt8, 1);
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SmartBuffer.prototype.readUInt16BE = makeReader(Buffer.prototype.readUInt16BE, 2);
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SmartBuffer.prototype.readUInt16LE = makeReader(Buffer.prototype.readUInt16LE, 2);
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SmartBuffer.prototype.readUInt32BE = makeReader(Buffer.prototype.readUInt32BE, 4);
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SmartBuffer.prototype.readUInt32LE = makeReader(Buffer.prototype.readUInt32LE, 4);
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SmartBuffer.prototype.readFloatBE = makeReader(Buffer.prototype.readFloatBE, 4);
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SmartBuffer.prototype.readFloatLE = makeReader(Buffer.prototype.readFloatLE, 4);
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SmartBuffer.prototype.readDoubleBE = makeReader(Buffer.prototype.readDoubleBE, 8);
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SmartBuffer.prototype.readDoubleLE = makeReader(Buffer.prototype.readDoubleLE, 8);
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/**
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* Reads a string of the given length.
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* @param length {Number} The length of the string to read. (Defaults to the length of the remaining data)
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* @param encoding {String} The encoding to use. (Defaults to encoding set in constructor, or utf8)
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* @returns {string} The string.
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*/
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SmartBuffer.prototype.readString = function (length, encoding) {
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var len = Math.min(length, this.length - this._readOffset) || (this.length - this._readOffset);
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var ret = this.buff.slice(this._readOffset, this._readOffset + len).toString(encoding || this.encoding);
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this._readOffset += len;
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return ret;
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};
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/**
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* Reads a null terminated string from the underlying buffer.
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* @param encoding {String} Encoding to use. Defaults to encoding set in constructor, or utf8.
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* @returns {string}
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*/
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SmartBuffer.prototype.readStringNT = function (encoding) {
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var nullpos = this.length;
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for (var i = this._readOffset; i < this.length; i++) {
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if (this.buff[i] == 0x00) {
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nullpos = i;
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break;
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}
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}
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var result = this.buff.slice(this._readOffset, nullpos);
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this._readOffset = nullpos + 1;
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return result.toString(encoding || this.encoding);
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};
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/**
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* Reads a specified number of bytes.
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* @param len {Number} Numbers of bytes to read. (Defaults to the remaining data length)
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* @returns {Buffer} Buffer containing the read bytes.
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*/
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SmartBuffer.prototype.readBuffer = function (len) {
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var endpoint = Math.min(this.length, this._readOffset + (typeof len === 'number' ? len : this.length));
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var ret = this.buff.slice(this._readOffset, endpoint);
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this._readOffset = endpoint;
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return ret;
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};
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/**
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* Reads a null terminated sequence of bytes from the underlying buffer.
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* @returns {Buffer} Buffer containing the read bytes.
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*/
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SmartBuffer.prototype.readBufferNT = function () {
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var nullpos = this.length;
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for (var i = this._readOffset; i < this.length; i++) {
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if (this.buff[i] == 0x00) {
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nullpos = i;
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break;
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}
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}
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var ret = this.buff.slice(this._readOffset, nullpos);
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this._readOffset = nullpos + 1;
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return ret;
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};
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/*
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Write Operations
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*/
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SmartBuffer.prototype.writeInt8 = makeWriter(Buffer.prototype.writeInt8, 1);
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SmartBuffer.prototype.writeInt16BE = makeWriter(Buffer.prototype.writeInt16BE, 2);
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SmartBuffer.prototype.writeInt16LE = makeWriter(Buffer.prototype.writeInt16LE, 2);
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SmartBuffer.prototype.writeInt32BE = makeWriter(Buffer.prototype.writeInt32BE, 4);
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SmartBuffer.prototype.writeInt32LE = makeWriter(Buffer.prototype.writeInt32LE, 4);
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SmartBuffer.prototype.writeUInt8 = makeWriter(Buffer.prototype.writeUInt8, 1);
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SmartBuffer.prototype.writeUInt16BE = makeWriter(Buffer.prototype.writeUInt16BE, 2);
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SmartBuffer.prototype.writeUInt16LE = makeWriter(Buffer.prototype.writeUInt16LE, 2);
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SmartBuffer.prototype.writeUInt32BE = makeWriter(Buffer.prototype.writeUInt32BE, 4);
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SmartBuffer.prototype.writeUInt32LE = makeWriter(Buffer.prototype.writeUInt32LE, 4);
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SmartBuffer.prototype.writeFloatBE = makeWriter(Buffer.prototype.writeFloatBE, 4);
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SmartBuffer.prototype.writeFloatLE = makeWriter(Buffer.prototype.writeFloatLE, 4);
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SmartBuffer.prototype.writeDoubleBE = makeWriter(Buffer.prototype.writeDoubleBE, 8);
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SmartBuffer.prototype.writeDoubleLE = makeWriter(Buffer.prototype.writeDoubleLE, 8);
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/**
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* Writes a string to the underlying buffer.
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* @param value {String} The string to write.
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* @param offset {Number} The offset to write the string to. (Encoding can also be set here in place of offset)
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* @param encoding {String} The encoding to use. (Defaults to encoding set in constructor, or to utf8)
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* @returns {*}
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*/
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SmartBuffer.prototype.writeString = function (value, offset, encoding) {
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var len, _offset, type = typeof offset;
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if (type === 'number') {
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_offset = offset;
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} else if (type === 'string') {
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encoding = offset;
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offset = this._writeOffset;
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} else {
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encoding = undefined;
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offset = this._writeOffset;
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}
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len = Buffer.byteLength(value, encoding || this.encoding);
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this._ensureWritable(len, _offset);
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this.buff.write(value, offset, len, encoding || this.encoding);
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this._writeOffset += len;
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return this;
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};
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/**
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* Writes a null terminated string to the underlying buffer.
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* @param value {String} The string to write.
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* @param offset {Number} The offset to write the string to. (Encoding can also be set here in place of offset)
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* @param encoding {String} The encoding to use. (Defaults to encoding set in constructor, or to utf8)
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* @returns {*}
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*/
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SmartBuffer.prototype.writeStringNT = function (value, offset, encoding) {
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this.writeString(value, offset, encoding);
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this.writeUInt8(0x00, (typeof offset === 'number' ? offset + value.length : this._writeOffset));
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return this;
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};
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/**
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* Writes a Buffer to the underlying buffer.
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* @param value {Buffer} The buffer to write.
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* @param offset {Number} The offset to write the Buffer to.
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* @returns {*}
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*/
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SmartBuffer.prototype.writeBuffer = function (value, offset) {
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var len = value.length;
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this._ensureWritable(len, offset);
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value.copy(this.buff, typeof offset === 'number' ? offset : this._writeOffset);
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this._writeOffset += len;
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return this;
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};
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/**
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* Writes a null terminated Buffer to the underlying buffer.
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* @param value {Buffer} The buffer to write.
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* @param offset {Number} The offset to write the Buffer to.
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* @returns {*}
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*/
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SmartBuffer.prototype.writeBufferNT = function (value, offset) {
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this.writeBuffer(value, offset);
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this.writeUInt8(0x00, (typeof offset === 'number' ? offset + value.length : this._writeOffset));
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return this;
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};
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/**
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* Resets the Endless Buffer.
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*/
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SmartBuffer.prototype.clear = function () {
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this._writeOffset = 0;
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this._readOffset = 0;
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this.length = 0;
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};
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/**
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* Gets the remaining number of bytes to be read from the existing Buffer.
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* @returns {number} The number of bytes remaining.
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*/
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SmartBuffer.prototype.remaining = function () {
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return this.length - this._readOffset;
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};
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/**
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* Skips the read position forward by the amount of given.
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* @param amount {Number} The amount of bytes to skip forward.
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*/
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SmartBuffer.prototype.skip = function (amount) {
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if (this._readOffset + amount > this.length)
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throw new Error('Target position is beyond the bounds of the data.');
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this._readOffset += amount;
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};
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/**
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* Rewinds the read position backward by the amount given.
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* @param amount {Number} The amount of bytes to reverse backward.
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*/
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SmartBuffer.prototype.rewind = function (amount) {
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if (this._readOffset - amount < 0)
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throw new Error('Target position is beyond the bounds of the data.');
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this._readOffset -= amount;
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};
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/**
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* Skips the read position to the given position.
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* @param position {Number} The position to skip to.
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*/
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SmartBuffer.prototype.skipTo = function (position) {
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if (position < 0 || position > this.length)
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throw new Error('Target position is beyond the bounds of the data.');
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this._readOffset = position;
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};
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/**
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* Gets the underlying Buffer.
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* @returns {*}
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*/
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SmartBuffer.prototype.toBuffer = function () {
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return this.buff.slice(0, this.length);
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};
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/**
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* Gets a string representation of the underlying Buffer.
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* @param encoding {String} Encoding to use. (Defaults to encoding set in constructor, or utf8.)
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* @returns {*}
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*/
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SmartBuffer.prototype.toString = function (encoding) {
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return this.buff.toString(encoding || this.encoding, 0, this.length);
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};
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/**
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* Destroys the underlying Buffer, and resets the SmartBuffer.
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*/
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SmartBuffer.prototype.destroy = function () {
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delete this.buff;
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this.clear();
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};
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return SmartBuffer;
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})();
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module.exports = SmartBuffer;
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