59 lines
2.1 KiB
JavaScript
59 lines
2.1 KiB
JavaScript
"use strict";
|
|
|
|
var assert = exports.assert = function(condition, message) {
|
|
if (!condition) {
|
|
throw new Error(message || "Assertion failed");
|
|
}
|
|
};
|
|
|
|
// Missing methods to read/write 64 bits integers from/to buffers.
|
|
// TODO(Kagami): Use this helpers in structs, pow, platform.
|
|
|
|
var MAX_SAFE_INTEGER = exports.MAX_SAFE_INTEGER = 9007199254740991;
|
|
|
|
exports.readUInt64BE = function(buf, offset, noAssert) {
|
|
offset = offset || 0;
|
|
var hi = buf.readUInt32BE(offset, noAssert);
|
|
var lo = buf.readUInt32BE(offset + 4, noAssert);
|
|
// Max safe number = 2^53 - 1 =
|
|
// 0b0000000000011111111111111111111111111111111111111111111111111111
|
|
// = 2097151*(2^32) + (2^32 - 1).
|
|
// So it's safe until hi <= 2097151. See
|
|
// <http://mdn.io/issafeinteger>, <https://stackoverflow.com/q/307179>
|
|
// for details.
|
|
assert(noAssert || hi <= 2097151, "Unsafe integer");
|
|
return hi * 4294967296 + lo;
|
|
};
|
|
|
|
var readTimestamp64BE = exports.readTimestamp64BE = function(buf, offset) {
|
|
offset = offset || 0;
|
|
var timeHi = buf.readUInt32BE(offset);
|
|
var timeLo = buf.readUInt32BE(offset + 4);
|
|
// JavaScript's Date object can't work with timestamps higher than
|
|
// 8640000000000 (~2^43, ~275760 year). Hope JavaScript will support
|
|
// 64-bit numbers up to this date.
|
|
assert(timeHi <= 2011, "Time is too high");
|
|
assert(timeHi !== 2011 || timeLo <= 2820767744, "Time is too high");
|
|
return timeHi * 4294967296 + timeLo;
|
|
};
|
|
|
|
exports.readTime64BE = function(buf, offset) {
|
|
var timestamp = readTimestamp64BE(buf, offset);
|
|
return new Date(timestamp * 1000);
|
|
};
|
|
|
|
exports.writeUInt64BE = function(buf, value, offset, noAssert) {
|
|
buf = buf || new Buffer(8);
|
|
offset = offset || 0;
|
|
assert(noAssert || value <= MAX_SAFE_INTEGER, "Unsafe integer");
|
|
buf.writeUInt32BE(Math.floor(value / 4294967296), offset, noAssert);
|
|
buf.writeUInt32BE(value % 4294967296, offset + 4, noAssert);
|
|
return buf;
|
|
};
|
|
var writeUInt64BE = exports.writeUInt64BE;
|
|
|
|
exports.writeTime64BE = function(buf, time, offset, noAssert) {
|
|
var timestamp = Math.floor(time.getTime() / 1000);
|
|
return writeUInt64BE(buf, timestamp, offset, noAssert);
|
|
};
|