8e959426e2
Javascript only supports 64 bit floating points, which have uint precision up to Math.pow(2, 53). We now support reading variable sized numbers up to that size. If the number is bigger than that, then we need to use BN.
250 lines
6.6 KiB
JavaScript
250 lines
6.6 KiB
JavaScript
var BufferWriter = require('../lib/bufferwriter');
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var BufferReader = require('../lib/bufferreader');
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var should = require('chai').should();
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var BN = require('../lib/bn');
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describe('BufferReader', function() {
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it('should make a new BufferReader', function() {
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var br = new BufferReader();
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should.exist(br);
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br = BufferReader();
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should.exist(br);
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});
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it('should create a new bufferreader with a buffer', function() {
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var buf = new Buffer(0);
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var br = new BufferReader(buf);
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should.exist(br);
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Buffer.isBuffer(br.buf).should.equal(true);
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});
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describe('#set', function() {
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it('should set pos', function() {
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should.exist(BufferReader().set({pos: 1}).pos);
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});
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});
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describe('#eof', function() {
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it('should return true for a blank br', function() {
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var br = new BufferReader({buf: new Buffer([])});
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br.eof().should.equal(true);
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});
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});
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describe('#buffer', function() {
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it('should return a buffer of this length', function() {
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var buf = new Buffer(10);
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buf.fill(0);
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var br = new BufferReader(buf);
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var buf2 = br.buffer(2);
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buf2.length.should.equal(2);
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br.eof().should.equal(false);
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br.pos.should.equal(2);
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});
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});
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describe('read', function() {
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it('should return the same buffer', function() {
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var buf = new Buffer([0]);
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var br = new BufferReader({buf: buf});
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br.read().toString('hex').should.equal(buf.toString('hex'));
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});
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});
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describe('#readUInt8', function() {
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it('should return 1', function() {
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var buf = new Buffer(1);
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buf.writeUInt8(1, 0);
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var br = new BufferReader({buf: buf});
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br.readUInt8().should.equal(1);
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});
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});
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describe('#readUInt16BE', function() {
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it('should return 1', function() {
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var buf = new Buffer(2);
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buf.writeUInt16BE(1, 0);
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var br = new BufferReader({buf: buf});
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br.readUInt16BE().should.equal(1);
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});
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});
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describe('#readUInt16LE', function() {
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it('should return 1', function() {
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var buf = new Buffer(2);
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buf.writeUInt16LE(1, 0);
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var br = new BufferReader({buf: buf});
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br.readUInt16LE().should.equal(1);
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});
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});
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describe('#readUInt32BE', function() {
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it('should return 1', function() {
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var buf = new Buffer(4);
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buf.writeUInt32BE(1, 0);
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var br = new BufferReader({buf: buf});
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br.readUInt32BE().should.equal(1);
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});
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});
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describe('#readUInt32LE', function() {
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it('should return 1', function() {
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var buf = new Buffer(4);
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buf.writeUInt32LE(1, 0);
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var br = new BufferReader({buf: buf});
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br.readUInt32LE().should.equal(1);
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});
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});
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describe('#readUInt64BEBN', function() {
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it('should return 1', function() {
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var buf = new Buffer(8);
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buf.fill(0);
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buf.writeUInt32BE(1, 4);
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var br = new BufferReader({buf: buf});
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br.readUInt64BEBN().toNumber().should.equal(1);
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});
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it('should return 2^64', function() {
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var buf = new Buffer(8);
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buf.fill(0xff);
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var br = new BufferReader({buf: buf});
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br.readUInt64BEBN().toNumber().should.equal(Math.pow(2, 64));
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});
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});
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describe('#readUInt64LEBN', function() {
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it('should return 1', function() {
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var buf = new Buffer(8);
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buf.fill(0);
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buf.writeUInt32LE(1, 0);
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var br = new BufferReader({buf: buf});
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br.readUInt64LEBN().toNumber().should.equal(1);
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});
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it('should return 2^30', function() {
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var buf = new Buffer(8);
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buf.fill(0);
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buf.writeUInt32LE(Math.pow(2, 30), 0);
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var br = new BufferReader({buf: buf});
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br.readUInt64LEBN().toNumber().should.equal(Math.pow(2, 30));
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});
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it('should return 0', function() {
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var buf = new Buffer(8);
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buf.fill(0);
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var br = new BufferReader({buf: buf});
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br.readUInt64LEBN().toNumber().should.equal(0);
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});
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it('should return 2^64', function() {
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var buf = new Buffer(8);
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buf.fill(0xff);
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var br = new BufferReader({buf: buf});
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br.readUInt64LEBN().toNumber().should.equal(Math.pow(2, 64));
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});
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});
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describe('#readVarInt', function() {
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it('should read a 1 byte varint', function() {
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var buf = new Buffer([50]);
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var br = new BufferReader({buf: buf});
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br.readVarInt().should.equal(50);
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});
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it('should read a 3 byte varint', function() {
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var buf = new Buffer([253, 253, 0]);
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var br = new BufferReader({buf: buf});
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br.readVarInt().should.equal(253);
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});
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it('should read a 5 byte varint', function() {
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var buf = new Buffer([254, 0, 0, 0, 0]);
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buf.writeUInt32LE(50000, 1);
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var br = new BufferReader({buf: buf});
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br.readVarInt().should.equal(50000);
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});
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it('should throw an error on a 9 byte varint over the javascript uint precision limit', function() {
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var buf = BufferWriter().writeVarIntBN(BN(Math.pow(2, 54).toString())).concat();
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var br = new BufferReader({buf: buf});
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(function() {
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br.readVarInt();
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}).should.throw('number too large to retain precision - use readVarIntBN');
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});
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it('should not throw an error on a 9 byte varint not over the javascript uint precision limit', function() {
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var buf = BufferWriter().writeVarIntBN(BN(Math.pow(2, 53).toString())).concat();
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var br = new BufferReader({buf: buf});
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(function() {
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br.readVarInt();
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}).should.not.throw('number too large to retain precision - use readVarIntBN');
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});
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});
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describe('#readVarIntBN', function() {
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it('should read a 1 byte varint', function() {
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var buf = new Buffer([50]);
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var br = new BufferReader({buf: buf});
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br.readVarIntBN().toNumber().should.equal(50);
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});
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it('should read a 3 byte varint', function() {
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var buf = new Buffer([253, 253, 0]);
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var br = new BufferReader({buf: buf});
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br.readVarIntBN().toNumber().should.equal(253);
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});
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it('should read a 5 byte varint', function() {
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var buf = new Buffer([254, 0, 0, 0, 0]);
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buf.writeUInt32LE(50000, 1);
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var br = new BufferReader({buf: buf});
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br.readVarIntBN().toNumber().should.equal(50000);
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});
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it('should read a 9 byte varint', function() {
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var buf = Buffer.concat([new Buffer([255]), new Buffer('ffffffffffffffff', 'hex')]);
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var br = new BufferReader({buf: buf});
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br.readVarIntBN().toNumber().should.equal(Math.pow(2, 64));
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});
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});
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describe('#reverse', function() {
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it('should reverse this [0, 1]', function() {
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var buf = new Buffer([0, 1]);
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var br = new BufferReader({buf: buf});
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br.reverse().read().toString('hex').should.equal('0100');
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});
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});
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});
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