move buffer-writer to external module
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brianc
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a5ee365116
commit
cee5f1d8b3
@ -4,7 +4,7 @@ var EventEmitter = require('events').EventEmitter;
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var util = require('util');
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var utils = require(__dirname + '/utils');
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var Writer = require(__dirname + '/writer');
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var Writer = require('buffer-writer');
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var Connection = function(config) {
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EventEmitter.call(this);
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128
lib/writer.js
128
lib/writer.js
@ -1,128 +0,0 @@
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//binary data writer tuned for creating
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//postgres message packets as effeciently as possible by reusing the
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//same buffer to avoid memcpy and limit memory allocations
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var Writer = function(size) {
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this.size = size || 1024;
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this.buffer = Buffer(this.size + 5);
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this.offset = 5;
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this.headerPosition = 0;
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};
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//resizes internal buffer if not enough size left
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Writer.prototype._ensure = function(size) {
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var remaining = this.buffer.length - this.offset;
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if(remaining < size) {
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var oldBuffer = this.buffer;
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this.buffer = new Buffer(oldBuffer.length + size);
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oldBuffer.copy(this.buffer);
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}
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};
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Writer.prototype.addInt32 = function(num) {
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this._ensure(4);
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this.buffer[this.offset++] = (num >>> 24 & 0xFF);
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this.buffer[this.offset++] = (num >>> 16 & 0xFF);
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this.buffer[this.offset++] = (num >>> 8 & 0xFF);
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this.buffer[this.offset++] = (num >>> 0 & 0xFF);
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return this;
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};
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Writer.prototype.addInt16 = function(num) {
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this._ensure(2);
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this.buffer[this.offset++] = (num >>> 8 & 0xFF);
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this.buffer[this.offset++] = (num >>> 0 & 0xFF);
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return this;
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};
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//for versions of node requiring 'length' as 3rd argument to buffer.write
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var writeString = function(buffer, string, offset, len) {
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buffer.write(string, offset, len);
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};
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//overwrite function for older versions of node
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if(Buffer.prototype.write.length === 3) {
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writeString = function(buffer, string, offset, len) {
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buffer.write(string, offset);
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};
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}
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Writer.prototype.addCString = function(string) {
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//just write a 0 for empty or null strings
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if(!string) {
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this._ensure(1);
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} else {
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var len = Buffer.byteLength(string);
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this._ensure(len + 1); //+1 for null terminator
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writeString(this.buffer, string, this.offset, len);
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this.offset += len;
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}
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this.buffer[this.offset++] = 0; // null terminator
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return this;
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};
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Writer.prototype.addChar = function(c) {
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this._ensure(1);
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writeString(this.buffer, c, this.offset, 1);
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this.offset++;
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return this;
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};
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Writer.prototype.addString = function(string) {
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string = string || "";
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var len = Buffer.byteLength(string);
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this._ensure(len);
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this.buffer.write(string, this.offset);
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this.offset += len;
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return this;
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};
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Writer.prototype.getByteLength = function() {
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return this.offset - 5;
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};
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Writer.prototype.add = function(otherBuffer) {
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this._ensure(otherBuffer.length);
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otherBuffer.copy(this.buffer, this.offset);
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this.offset += otherBuffer.length;
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return this;
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};
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Writer.prototype.clear = function() {
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this.offset = 5;
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this.headerPosition = 0;
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this.lastEnd = 0;
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};
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//appends a header block to all the written data since the last
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//subsequent header or to the beginning if there is only one data block
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Writer.prototype.addHeader = function(code, last) {
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var origOffset = this.offset;
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this.offset = this.headerPosition;
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this.buffer[this.offset++] = code;
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//length is everything in this packet minus the code
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this.addInt32(origOffset - (this.headerPosition+1));
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//set next header position
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this.headerPosition = origOffset;
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//make space for next header
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this.offset = origOffset;
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if(!last) {
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this._ensure(5);
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this.offset += 5;
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}
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};
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Writer.prototype.join = function(code) {
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if(code) {
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this.addHeader(code, true);
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}
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return this.buffer.slice(code ? 0 : 5, this.offset);
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};
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Writer.prototype.flush = function(code) {
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var result = this.join(code);
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this.clear();
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return result;
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};
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module.exports = Writer;
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@ -19,7 +19,7 @@
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"main": "./lib",
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"dependencies": {
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"generic-pool": "2.0.2",
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"deprecate": "~0.1.0"
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"buffer-writer": "1.0.0"
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},
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"devDependencies": {
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"jshint": "git://github.com/jshint/jshint.git"
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@ -1,196 +0,0 @@
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require(__dirname + "/test-helper");
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var Writer = require(__dirname + "/../../lib/writer");
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test('adding int32', function() {
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var testAddingInt32 = function(int, expectedBuffer) {
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test('writes ' + int, function() {
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var subject = new Writer();
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var result = subject.addInt32(int).join();
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assert.equalBuffers(result, expectedBuffer);
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})
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}
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testAddingInt32(0, [0, 0, 0, 0]);
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testAddingInt32(1, [0, 0, 0, 1]);
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testAddingInt32(256, [0, 0, 1, 0]);
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test('writes largest int32', function() {
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//todo need to find largest int32 when I have internet access
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return false;
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})
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test('writing multiple int32s', function() {
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var subject = new Writer();
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var result = subject.addInt32(1).addInt32(10).addInt32(0).join();
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assert.equalBuffers(result, [0, 0, 0, 1, 0, 0, 0, 0x0a, 0, 0, 0, 0]);
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})
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test('having to resize the buffer', function() {
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test('after resize correct result returned', function() {
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var subject = new Writer(10);
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subject.addInt32(1).addInt32(1).addInt32(1)
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assert.equalBuffers(subject.join(), [0, 0, 0, 1, 0, 0, 0, 1, 0, 0, 0, 1])
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})
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})
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})
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test('int16', function() {
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test('writes 0', function() {
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var subject = new Writer();
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var result = subject.addInt16(0).join();
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assert.equalBuffers(result, [0,0]);
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})
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test('writes 400', function() {
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var subject = new Writer();
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var result = subject.addInt16(400).join();
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assert.equalBuffers(result, [1, 0x90])
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})
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test('writes many', function() {
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var subject = new Writer();
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var result = subject.addInt16(0).addInt16(1).addInt16(2).join();
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assert.equalBuffers(result, [0, 0, 0, 1, 0, 2])
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})
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test('resizes if internal buffer fills up', function() {
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var subject = new Writer(3);
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var result = subject.addInt16(2).addInt16(3).join();
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assert.equalBuffers(result, [0, 2, 0, 3])
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})
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})
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test('cString', function() {
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test('writes empty cstring', function() {
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var subject = new Writer();
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var result = subject.addCString().join();
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assert.equalBuffers(result, [0])
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})
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test('writes two empty cstrings', function() {
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var subject = new Writer();
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var result = subject.addCString("").addCString("").join();
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assert.equalBuffers(result, [0, 0])
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})
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test('writes non-empty cstring', function() {
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var subject = new Writer();
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var result = subject.addCString("!!!").join();
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assert.equalBuffers(result, [33, 33, 33, 0]);
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})
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test('resizes if reached end', function() {
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var subject = new Writer(3);
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var result = subject.addCString("!!!").join();
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assert.equalBuffers(result, [33, 33, 33, 0]);
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})
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test('writes multiple cstrings', function() {
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var subject = new Writer();
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var result = subject.addCString("!").addCString("!").join();
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assert.equalBuffers(result, [33, 0, 33, 0]);
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})
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})
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test('writes char', function() {
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var subject = new Writer(2);
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var result = subject.addChar('a').addChar('b').addChar('c').join();
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assert.equalBuffers(result, [0x61, 0x62, 0x63])
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})
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test('gets correct byte length', function() {
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var subject = new Writer(5);
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assert.equal(subject.getByteLength(), 0)
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subject.addInt32(0)
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assert.equal(subject.getByteLength(), 4)
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subject.addCString("!")
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assert.equal(subject.getByteLength(), 6)
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})
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test('can add arbitrary buffer to the end', function() {
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var subject = new Writer(4);
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subject.addCString("!!!")
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var result = subject.add(Buffer("@@@")).join();
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assert.equalBuffers(result, [33, 33, 33, 0, 0x40, 0x40, 0x40]);
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})
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test('can write normal string', function() {
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var subject = new Writer(4);
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var result = subject.addString("!").join();
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assert.equalBuffers(result, [33]);
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test('can write cString too', function() {
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var result = subject.addCString("!").join();
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assert.equalBuffers(result, [33, 33, 0]);
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test('can resize', function() {
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var result = subject.addString("!!").join();
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assert.equalBuffers(result, [33, 33, 0, 33, 33]);
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})
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})
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})
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test('clearing', function() {
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var subject = new Writer();
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subject.addCString("@!!#!#");
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subject.addInt32(10401);
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subject.clear();
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assert.equalBuffers(subject.join(), []);
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test('can keep writing', function() {
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var joinedResult = subject.addCString("!").addInt32(9).addInt16(2).join();
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assert.equalBuffers(joinedResult, [33, 0, 0, 0, 0, 9, 0, 2]);
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test('flush', function() {
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var flushedResult = subject.flush();
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test('returns result', function() {
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assert.equalBuffers(flushedResult, [33, 0, 0, 0, 0, 9, 0, 2])
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})
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test('clears the writer', function() {
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assert.equalBuffers(subject.join(), [])
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assert.equalBuffers(subject.flush(), [])
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})
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})
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})
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})
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test("resizing to much larger", function() {
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var subject = new Writer(2);
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var string = "!!!!!!!!";
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var result = subject.addCString(string).flush();
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assert.equalBuffers(result, [33, 33, 33, 33, 33, 33, 33, 33, 0])
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})
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test("flush", function() {
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test('added as a hex code to a full writer', function() {
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var subject = new Writer(2);
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var result = subject.addCString("!").flush(0x50)
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assert.equalBuffers(result, [0x50, 0, 0, 0, 6, 33, 0]);
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})
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test('added as a hex code to a non-full writer', function() {
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var subject = new Writer(10).addCString("!");
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var joinedResult = subject.join(0x50);
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var result = subject.flush(0x50);
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assert.equalBuffers(result, [0x50, 0, 0, 0, 6, 33, 0]);
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})
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test('added as a hex code to a buffer which requires resizing', function() {
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var result = new Writer(2).addCString("!!!!!!!!").flush(0x50);
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assert.equalBuffers(result, [0x50, 0, 0, 0, 0x0D, 33, 33, 33, 33, 33, 33, 33, 33, 0]);
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})
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})
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test("header", function() {
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test('adding two packets with headers', function() {
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var subject = new Writer(10).addCString("!");
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subject.addHeader(0x50);
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subject.addCString("!!");
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subject.addHeader(0x40);
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subject.addCString("!");
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var result = subject.flush(0x10);
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assert.equalBuffers(result, [0x50, 0, 0, 0, 6, 33, 0, 0x40, 0, 0, 0, 7, 33, 33, 0, 0x10, 0, 0, 0, 6, 33, 0 ]);
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})
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})
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