telebit.js/machine.js

139 lines
4.0 KiB
JavaScript

'use strict';
var machine = {};
machine._version = 1;
machine.state = 0;
machine.states = { 0: 'version', 1: 'headerLength', 2: 'header', 3: 'data'/*, 4: 'error'*/ };
machine.states_length = Object.keys(machine.states).length;
machine.chunkIndex = 0;
machine.fns = {};
function debug(chunk, i, len) {
i = i || 0;
len = len || chunk.length - i;
console.log(chunk.slice(i, len)[0]);
console.log(chunk);
console.log('state:', machine.states[machine.state]);
console.log('statei:', machine.state);
console.log('index:', machine.chunkIndex);
}
machine.fns.version = function (chunk) {
if ((255 - machine._version) !== chunk[machine.chunkIndex]) {
console.error("not v" + machine._version + " (or data is corrupt)");
// no idea how to fix this yet
}
machine.chunkIndex += 1;
};
machine.headerLen = 0;
machine.fns.headerLength = function (chunk) {
machine.headerLen = chunk[machine.chunkIndex];
machine.chunkIndex += 1;
};
machine.buf = null;
machine.bufIndex = 0;
//var buf = Buffer.alloc(4096);
machine.fns.header = function (chunk) {
var curSize = machine.bufIndex + (chunk.length - machine.chunkIndex);
var partLen = 0;
var str = '';
if (curSize < machine.headerLen) {
// I still don't have the whole header,
// so just create a large enough buffer,
// write these bits, and wait for the next chunk.
if (!machine.buf) {
machine.buf = Buffer.alloc(machine.headerLen);
}
partLen = machine.headerLen - machine.bufIndex;
machine.buf.write(chunk.slice(machine.chunkIndex, machine.chunkIndex + partLen), machine.bufIndex);
machine.chunkIndex += partLen; // this MUST be chunk.length
machine.bufIndex += partLen;
}
else {
// it's now ready to discover the whole header
if (machine.buf) {
str += machine.buf.slice(0, machine.bufIndex).toString();
}
partLen = machine.headerLen - str.length;
str += chunk.slice(machine.chunkIndex, machine.chunkIndex + partLen).toString();
machine.chunkIndex += partLen;
// TODO maybe just use maxlen of buffer
machine.buf = null; // back to null
machine.bufIndex = 0; // back to 0
machine._headers = str.split(/,/g);
console.log(partLen);
console.log('');
console.log(chunk.toString());
console.log('');
console.log(str);
console.log(machine._headers);
machine.family = machine._headers[0];
machine.address = machine._headers[1];
machine.port = machine._headers[2];
machine.bodyLen = machine._headers[3];
}
};
machine.fns.data = function (chunk) {
var curSize = machine.bufIndex + (chunk.length - machine.chunkIndex);
var partLen = 0;
var buf;
if (curSize < machine.bodyLen) {
// I still don't have the whole header,
// so just create a large enough buffer,
// write these bits, and wait for the next chunk.
if (!machine.buf) {
machine.buf = Buffer.alloc(machine.bodyLen);
}
partLen = machine.bodyLen - machine.bufIndex;
machine.buf.write(chunk.slice(machine.chunkIndex, machine.chunkIndex + partLen), machine.bufIndex);
//machine.chunkIndex += partLen; // this MUST be chunk.length
machine.bufIndex += partLen;
return;
}
// it's now ready to discover the whole header
if (!machine.buf) {
buf = chunk;
machine.chunkIndex = chunk.length;
}
else {
partLen = machine.bodyLen - machine.bufIndex;
machine.buf.write(chunk.slice(machine.chunkIndex, machine.chunkIndex + partLen), machine.bufIndex);
machine.chunkIndex += partLen;
}
machine.onMessage({
family: machine.family
, address: machine.address
, port: machine.port
, data: buf
});
// TODO maybe just use maxlen of buffer
machine.buf = null; // back to null
machine.bufIndex = 0; // back to 0
};
machine.fns.addChunk = function (chunk) {
machine.chunkIndex = 0;
while (machine.chunkIndex < chunk.length) {
console.log(machine.state);
machine.fns[machine.states[machine.state]](chunk);
machine.state += 1;
machine.state %= machine.states_length;
}
};
module.exports = machine;
process.on('uncaughtException', function () {
debug(Buffer.from('0'));
});