antelope-webauthn
Version:
A WebAuthn.io crypto utility for generating signatures, creating public keys, and verifying them, designed for Antelope-based blockchains such as Vaulta, WAX, and other related platforms. This package provides convenient tools to handle key pair generatio
210 lines (209 loc) • 7.42 kB
JavaScript
const POW_2_24 = 5.960464477539063e-8, POW_2_32 = 4294967296;
export default function decodeCBOR(data, tagger, simpleValue) {
var dataView = new DataView(data);
var 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() {
var tempArrayBuffer = new ArrayBuffer(4);
var tempDataView = new DataView(tempArrayBuffer);
var value = readUint16();
var sign = value & 0x8000;
var exponent = value & 0x7c00;
var 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) {
var initialByte = readUint8();
if (initialByte === 0xff)
return -1;
var length = readLength(initialByte & 0x1f);
if (length < 0 || initialByte >> 5 !== majorType)
throw "Invalid indefinite length element";
return length;
}
function appendUtf16Data(utf16data, length) {
for (var i = 0; i < length; ++i) {
var 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() {
var initialByte = readUint8();
var majorType = initialByte >> 5;
var additionalInformation = initialByte & 0x1f;
var i;
var 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) {
var elements = [];
var fullArrayLength = 0;
while ((length = readIndefiniteStringLength(majorType)) >= 0) {
fullArrayLength += length;
elements.push(readArrayBuffer(length));
}
var fullArray = new Uint8Array(fullArrayLength);
var 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:
var utf16data = [];
if (length < 0) {
while ((length = readIndefiniteStringLength(majorType)) >= 0)
appendUtf16Data(utf16data, length);
}
else
appendUtf16Data(utf16data, length);
return String.fromCharCode.apply(null, utf16data);
case 4:
var 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:
var retObject = {};
for (i = 0; i < length || (length < 0 && !readBreak()); ++i) {
var 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);
}
}
}
var ret = decodeItem();
if (offset !== data.byteLength)
throw "Remaining bytes";
return ret;
}