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refactored parser to be more stateful

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This commit is contained in:
brianc 2010-09-29 00:30:35 -05:00
parent 9688d8947f
commit 2c9d26d7f6
2 changed files with 34 additions and 33 deletions
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50
lib/index.js
View File

@ -45,27 +45,27 @@ Client.prototype.connect = function() {
});
};
var Parser = function() {
var Parser = function(buffer) {
this.offset = 0;
this.buffer = buffer;
};
var p = Parser.prototype;
p.parse = function(buffer) {
switch(buffer[this.offset]) {
switch(this.buffer[this.offset]) {
case UTF8.R:
return this.parseR(buffer);
return this.parseR();
case UTF8.S:
return this.parseS(buffer);
return this.parseS();
default:
throw new Error("Unsupported message ID");
}
};
p.parseR = function(buffer) {
var type = buffer[this.offset++];
var length = this.parseLength(buffer);
p.parseR = function() {
var type = this.buffer[this.offset++];
var length = this.parseLength();
if(length == 8) {
return {
name: 'AuthenticationOk',
@ -76,18 +76,10 @@ p.parseR = function(buffer) {
throw new Error("Unknown AuthenticatinOk message type");
};
p.parseS = function(buffer) {
var offset = 0;
var type = buffer[this.offset++];
var length = this.parseLength(buffer,this.offset);
offset += 4;
var start = this.offset;
while(buffer[offset++]) { }
var end = offset -1;
var parameterName = buffer.toString('utf8',start, end);
var start = offset;
while(buffer[offset++]) { }
var end = offset - 1;
var parameterValue = buffer.toString('utf8', start, end);
var type = this.buffer[this.offset++];
var length = this.parseLength(this.buffer);
var parameterName = this.parseCString();
var parameterValue = this.parseCString();
return {
name: 'ParameterStatus',
id: 'S',
@ -97,19 +89,19 @@ p.parseS = function(buffer) {
}
};
p.parseLength = function(buffer) {
var length = ((buffer[this.offset++] << 24) +
(buffer[this.offset++] << 16) +
(buffer[this.offset++] << 8) +
buffer[this.offset++]);
return length;
p.parseLength = function() {
var buffer = this.buffer;
return ((buffer[this.offset++] << 24) +
(buffer[this.offset++] << 16) +
(buffer[this.offset++] << 8) +
buffer[this.offset++]);
};
p.parseCString = function(buffer) {
var start = this.offset;
while(buffer[this.offset++]) { };
var end = this.offset - 1;
return buffer.toString('utf8',start, end);
while(this.buffer[this.offset++]) { };
return this.buffer.toString('utf8',start, this.offset - 1);
};

17
test/parser-tests.js
View File

@ -1,7 +1,8 @@
require(__dirname+'/test-helper');
test('Parser on single messages', function() {
test('parses AuthenticationOk message', function() {
var result = new Parser().parse(Buffer([0x52, 00, 00, 00, 08, 00, 00, 00, 00]));
var buffer = Buffer([0x52, 00, 00, 00, 08, 00, 00, 00, 00]);
var result = new Parser(buffer).parse();
assert.equal(result.name, 'AuthenticationOk');
assert.equal(result.id, 'R');
assert.equal(result.length, 8);
@ -11,7 +12,8 @@ test('Parser on single messages', function() {
var firstString = [0x63, 0x6c, 0x69, 0x65, 0x6e, 0x74, 0x5f, 0x65, 0x6e, 0x63, 0x6f, 0x64, 0x69, 0x6e, 0x67, 0];
var secondString = [0x55, 0x54, 0x46, 0x38, 0];
var bytes = [0x53, 0, 0, 0, 0x19].concat(firstString).concat(secondString);
var result = new Parser().parse(Buffer(bytes));
var buffer = Buffer(bytes);
var result = new Parser(buffer).parse();
assert.equal(result.name, 'ParameterStatus');
assert.equal(result.id, 'S');
assert.equal(result.length, 25);
@ -20,13 +22,20 @@ test('Parser on single messages', function() {
});
test('parses normal CString', function() {
var result = new Parser().parseCString(Buffer([33,00]));
var result = new Parser(Buffer([33,0])).parseCString();
assert.equal(result,"!");
});
test('parses empty CString', function() {
var result = new Parser().parseCString(Buffer([0]));
var result = new Parser(Buffer([0])).parseCString();
assert.equal(result, '');
});
test('parses length', function() {
var parser = new Parser(Buffer([0,0,0,3]));
var result = parser.parseLength();
assert.equal(result, 3);
assert.equal(parser.offset, 4);
});
});