@polkadot/util
Version:
A collection of useful utilities for @polkadot
74 lines (73 loc) • 2.98 kB
JavaScript
;
Object.defineProperty(exports, "__esModule", { value: true });
exports.u8aToBigInt = u8aToBigInt;
const x_bigint_1 = require("@polkadot/x-bigint");
const consts_js_1 = require("../bi/consts.js");
const U8_MAX = (0, x_bigint_1.BigInt)(256);
const U16_MAX = (0, x_bigint_1.BigInt)(256 * 256);
const U64_MAX = (0, x_bigint_1.BigInt)('0x10000000000000000');
/**
* @name u8aToBigInt
* @summary Creates a BigInt from a Uint8Array object.
*/
function u8aToBigInt(value, { isLe = true, isNegative = false } = {}) {
// slice + reverse is expensive, however SCALE is LE by default so this is the path
// we are most interested in (the BE is added for the sake of being comprehensive)
if (!isLe) {
value = value.slice().reverse();
}
const count = value.length;
if (isNegative && count && (value[count - 1] & 0x80)) {
switch (count) {
case 0:
return (0, x_bigint_1.BigInt)(0);
case 1:
return (0, x_bigint_1.BigInt)(((value[0] ^ 0x0000_00ff) * -1) - 1);
case 2:
return (0, x_bigint_1.BigInt)((((value[0] + (value[1] << 8)) ^ 0x0000_ffff) * -1) - 1);
case 4:
return (0, x_bigint_1.BigInt)((((value[0] + (value[1] << 8) + (value[2] << 16) + (value[3] * 0x1_00_00_00)) ^ 0xffff_ffff) * -1) - 1);
}
const dvI = new DataView(value.buffer, value.byteOffset);
if (count === 8) {
return dvI.getBigInt64(0, true);
}
let result = (0, x_bigint_1.BigInt)(0);
const mod = count % 2;
for (let i = count - 2; i >= mod; i -= 2) {
result = (result * U16_MAX) + (0, x_bigint_1.BigInt)(dvI.getUint16(i, true) ^ 0xffff);
}
if (mod) {
result = (result * U8_MAX) + (0, x_bigint_1.BigInt)(value[0] ^ 0xff);
}
return (result * -consts_js_1._1n) - consts_js_1._1n;
}
switch (count) {
case 0:
return (0, x_bigint_1.BigInt)(0);
case 1:
return (0, x_bigint_1.BigInt)(value[0]);
case 2:
return (0, x_bigint_1.BigInt)(value[0] + (value[1] << 8));
case 4:
return (0, x_bigint_1.BigInt)(value[0] + (value[1] << 8) + (value[2] << 16) + (value[3] * 0x1_00_00_00));
}
const dvI = new DataView(value.buffer, value.byteOffset);
switch (count) {
case 8:
return dvI.getBigUint64(0, true);
case 16:
return (dvI.getBigUint64(8, true) * U64_MAX) + dvI.getBigUint64(0, true);
default: {
let result = (0, x_bigint_1.BigInt)(0);
const mod = count % 2;
for (let i = count - 2; i >= mod; i -= 2) {
result = (result * U16_MAX) + (0, x_bigint_1.BigInt)(dvI.getUint16(i, true));
}
if (mod) {
result = (result * U8_MAX) + (0, x_bigint_1.BigInt)(value[0]);
}
return result;
}
}
}