@gang-js/core
Version:
a state sharing algorithm
384 lines (383 loc) • 14.2 kB
JavaScript
/*
* The MIT License (MIT)
*
* Copyright (c) 2014-2016 Patrick Gansterer <paroga@paroga.com>
*
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to deal
* in the Software without restriction, including without limitation the rights
* to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
* copies of the Software, and to permit persons to whom the Software is
* furnished to do so, subject to the following conditions:
*
* The above copyright notice and this permission notice shall be included in all
* copies or substantial portions of the Software.
*
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
* SOFTWARE.
*/
/* eslint-disable */
const POW_2_24 = 5.960464477539063e-8, POW_2_32 = 4294967296, POW_2_53 = 9007199254740992;
function encode(value) {
let data = new ArrayBuffer(256);
let dataView = new DataView(data);
let lastLength;
let offset = 0;
function prepareWrite(length) {
let newByteLength = data.byteLength;
const requiredLength = offset + length;
while (newByteLength < requiredLength)
newByteLength <<= 1;
if (newByteLength !== data.byteLength) {
const oldDataView = dataView;
data = new ArrayBuffer(newByteLength);
dataView = new DataView(data);
const uint32count = (offset + 3) >> 2;
for (let i = 0; i < uint32count; ++i)
dataView.setUint32(i << 2, oldDataView.getUint32(i << 2));
}
lastLength = length;
return dataView;
}
function commitWrite(_) {
offset += lastLength;
}
function writeFloat64(value) {
commitWrite(prepareWrite(8).setFloat64(offset, value));
}
function writeUint8(value) {
commitWrite(prepareWrite(1).setUint8(offset, value));
}
function writeUint8Array(value) {
const dataView = prepareWrite(value.length);
for (let i = 0; i < value.length; ++i)
dataView.setUint8(offset + i, value[i]);
commitWrite();
}
function writeUint16(value) {
commitWrite(prepareWrite(2).setUint16(offset, value));
}
function writeUint32(value) {
commitWrite(prepareWrite(4).setUint32(offset, value));
}
function writeUint64(value) {
const low = value % POW_2_32;
const high = (value - low) / POW_2_32;
const dataView = prepareWrite(8);
dataView.setUint32(offset, high);
dataView.setUint32(offset + 4, low);
commitWrite();
}
function writeTypeAndLength(type, length) {
if (length < 24) {
writeUint8((type << 5) | length);
}
else if (length < 0x100) {
writeUint8((type << 5) | 24);
writeUint8(length);
}
else if (length < 0x10000) {
writeUint8((type << 5) | 25);
writeUint16(length);
}
else if (length < 0x100000000) {
writeUint8((type << 5) | 26);
writeUint32(length);
}
else {
writeUint8((type << 5) | 27);
writeUint64(length);
}
}
function encodeItem(value) {
let i;
if (value === false)
return writeUint8(0xf4);
if (value === true)
return writeUint8(0xf5);
if (value === null)
return writeUint8(0xf6);
if (value === undefined)
return writeUint8(0xf7);
switch (typeof value) {
case 'number':
if (Math.floor(value) === value) {
if (0 <= value && value <= POW_2_53)
return writeTypeAndLength(0, value);
if (-POW_2_53 <= value && value < 0)
return writeTypeAndLength(1, -(value + 1));
}
writeUint8(0xfb);
return writeFloat64(value);
case 'string':
const utf8data = [];
for (let i = 0; i < value.length; ++i) {
let charCode = value.charCodeAt(i);
if (charCode < 0x80) {
utf8data.push(charCode);
}
else if (charCode < 0x800) {
utf8data.push(0xc0 | (charCode >> 6));
utf8data.push(0x80 | (charCode & 0x3f));
}
else if (charCode < 0xd800) {
utf8data.push(0xe0 | (charCode >> 12));
utf8data.push(0x80 | ((charCode >> 6) & 0x3f));
utf8data.push(0x80 | (charCode & 0x3f));
}
else {
charCode = (charCode & 0x3ff) << 10;
charCode |= value.charCodeAt(++i) & 0x3ff;
charCode += 0x10000;
utf8data.push(0xf0 | (charCode >> 18));
utf8data.push(0x80 | ((charCode >> 12) & 0x3f));
utf8data.push(0x80 | ((charCode >> 6) & 0x3f));
utf8data.push(0x80 | (charCode & 0x3f));
}
}
writeTypeAndLength(3, utf8data.length);
return writeUint8Array(utf8data);
default:
let length;
if (Array.isArray(value)) {
length = value.length;
writeTypeAndLength(4, length);
for (i = 0; i < length; ++i)
encodeItem(value[i]);
}
else if (value instanceof Uint8Array) {
writeTypeAndLength(2, value.length);
writeUint8Array(value);
}
else {
const keys = Object.keys(value);
length = keys.length;
writeTypeAndLength(5, length);
for (i = 0; i < length; ++i) {
const key = keys[i];
encodeItem(key);
encodeItem(value[key]);
}
}
}
}
encodeItem(value);
if ('slice' in data)
return data.slice(0, offset);
const ret = new ArrayBuffer(offset);
const retView = new DataView(ret);
for (let i = 0; i < offset; ++i)
retView.setUint8(i, dataView.getUint8(i));
return ret;
}
function decode(data, tagger, simpleValue) {
const dataView = new DataView(data);
let offset = 0;
if (typeof tagger !== 'function')
tagger = function (value) {
return value;
};
if (typeof simpleValue !== 'function')
simpleValue = function () {
return undefined;
};
function commitRead(length, value) {
offset += length;
return value;
}
function readArrayBuffer(length) {
return commitRead(length, new Uint8Array(data, offset, length));
}
function readFloat16() {
const tempArrayBuffer = new ArrayBuffer(4);
const tempDataView = new DataView(tempArrayBuffer);
const value = readUint16();
const sign = value & 0x8000;
let exponent = value & 0x7c00;
const fraction = value & 0x03ff;
if (exponent === 0x7c00)
exponent = 0xff << 10;
else if (exponent !== 0)
exponent += (127 - 15) << 10;
else if (fraction !== 0)
return (sign ? -1 : 1) * fraction * POW_2_24;
tempDataView.setUint32(0, (sign << 16) | (exponent << 13) | (fraction << 13));
return tempDataView.getFloat32(0);
}
function readFloat32() {
return commitRead(4, dataView.getFloat32(offset));
}
function readFloat64() {
return commitRead(8, dataView.getFloat64(offset));
}
function readUint8() {
return commitRead(1, dataView.getUint8(offset));
}
function readUint16() {
return commitRead(2, dataView.getUint16(offset));
}
function readUint32() {
return commitRead(4, dataView.getUint32(offset));
}
function readUint64() {
return readUint32() * POW_2_32 + readUint32();
}
function readBreak() {
if (dataView.getUint8(offset) !== 0xff)
return false;
offset += 1;
return true;
}
function readLength(additionalInformation) {
if (additionalInformation < 24)
return additionalInformation;
if (additionalInformation === 24)
return readUint8();
if (additionalInformation === 25)
return readUint16();
if (additionalInformation === 26)
return readUint32();
if (additionalInformation === 27)
return readUint64();
if (additionalInformation === 31)
return -1;
throw 'Invalid length encoding';
}
function readIndefiniteStringLength(majorType) {
const initialByte = readUint8();
if (initialByte === 0xff)
return -1;
const length = readLength(initialByte & 0x1f);
if (length < 0 || initialByte >> 5 !== majorType)
throw 'Invalid indefinite length element';
return length;
}
function appendUtf16Data(utf16data, length) {
for (let i = 0; i < length; ++i) {
let value = readUint8();
if (value & 0x80) {
if (value < 0xe0) {
value = ((value & 0x1f) << 6) | (readUint8() & 0x3f);
length -= 1;
}
else if (value < 0xf0) {
value = ((value & 0x0f) << 12) | ((readUint8() & 0x3f) << 6) | (readUint8() & 0x3f);
length -= 2;
}
else {
value =
((value & 0x0f) << 18) | ((readUint8() & 0x3f) << 12) | ((readUint8() & 0x3f) << 6) | (readUint8() & 0x3f);
length -= 3;
}
}
if (value < 0x10000) {
utf16data.push(value);
}
else {
value -= 0x10000;
utf16data.push(0xd800 | (value >> 10));
utf16data.push(0xdc00 | (value & 0x3ff));
}
}
}
function decodeItem() {
const initialByte = readUint8();
const majorType = initialByte >> 5;
const additionalInformation = initialByte & 0x1f;
let i;
let length;
if (majorType === 7) {
switch (additionalInformation) {
case 25:
return readFloat16();
case 26:
return readFloat32();
case 27:
return readFloat64();
}
}
length = readLength(additionalInformation);
if (length < 0 && (majorType < 2 || 6 < majorType))
throw 'Invalid length';
switch (majorType) {
case 0:
return length;
case 1:
return -1 - length;
case 2:
if (length < 0) {
const elements = [];
let fullArrayLength = 0;
while ((length = readIndefiniteStringLength(majorType)) >= 0) {
fullArrayLength += length;
elements.push(readArrayBuffer(length));
}
const fullArray = new Uint8Array(fullArrayLength);
let fullArrayOffset = 0;
for (i = 0; i < elements.length; ++i) {
fullArray.set(elements[i], fullArrayOffset);
fullArrayOffset += elements[i].length;
}
return fullArray;
}
return readArrayBuffer(length);
case 3:
const utf16data = [];
if (length < 0) {
while ((length = readIndefiniteStringLength(majorType)) >= 0)
appendUtf16Data(utf16data, length);
}
else
appendUtf16Data(utf16data, length);
return String.fromCharCode.apply(null, utf16data);
case 4:
let retArray;
if (length < 0) {
retArray = [];
while (!readBreak())
retArray.push(decodeItem());
}
else {
retArray = new Array(length);
for (i = 0; i < length; ++i)
retArray[i] = decodeItem();
}
return retArray;
case 5:
const retObject = {};
for (i = 0; i < length || (length < 0 && !readBreak()); ++i) {
const key = decodeItem();
retObject[key] = decodeItem();
}
return retObject;
case 6:
return tagger(decodeItem(), length);
case 7:
switch (length) {
case 20:
return false;
case 21:
return true;
case 22:
return null;
case 23:
return undefined;
default:
return simpleValue(length);
}
}
}
const ret = decodeItem();
if (offset !== data.byteLength)
throw 'Remaining bytes';
return ret;
}
export const CBOR = {
encode,
decode
};