@iden3/js-merkletree/dist/node/esm/lib/utils/bytes.js

javascript sparse merkle tree library

import { HASH_BYTES_LENGTH } from '../../constants';
import { checkBigIntInField } from './crypto';
export const bytesEqual = (b1, b2) => {
    return b1.every((ele, idx) => ele === b2[idx]);
};
// TODO: might be make this generic over typed arrays?
export const swapEndianness = (bytes) => {
    return bytes.slice().reverse();
};
export const bytes2BinaryString = (bytes) => {
    return '0b' + bytes.reduce((acc, i) => acc + i.toString(2).padStart(8, '0'), '');
};
export const testBit = (bitMap, n) => {
    return (bitMap[parseInt((n / 8).toString())] & (1 << n % 8)) !== 0;
};
export const testBitBigEndian = (bitMap, n) => {
    return (bitMap[bitMap.length - parseInt(`${n / 8}`) - 1] & (1 << n % 8)) !== 0;
};
// SetBitBigEndian sets the bit n in the bitmap to 1, in Big Endian.
export const setBitBigEndian = (bitMap, n) => {
    bitMap[bitMap.length - parseInt(`${n / 8}`) - 1] |= 1 << n % 8;
};
const hextable = '0123456789abcdef';
export const bytes2Hex = (u) => {
    const arr = new Array(u.length * 2);
    let j = 0;
    u.forEach((v) => {
        arr[j] = hextable[parseInt((v >> 4).toString(10))];
        arr[j + 1] = hextable[parseInt((v & 15).toString(10))];
        j += 2;
    });
    return arr.join('');
};
// NOTE: `bytes` should be big endian
// bytes recieved from Hash.value getter are safe to use since their endianness is swapped, for the same reason the private Hash.bytes { stored in little endian } should never be used
export const newBigIntFromBytes = (bytes) => {
    if (bytes.length !== HASH_BYTES_LENGTH) {
        throw `Expected 32 bytes, found ${bytes.length} bytes`;
    }
    const bigNum = BigInt(bytes2BinaryString(bytes));
    if (!checkBigIntInField(bigNum)) {
        throw 'NewBigIntFromHashBytes: Value not inside the Finite Field';
    }
    return bigNum;
};
export const str2Bytes = (str) => new Uint8Array(str.length * 2).map((_, i) => str.charCodeAt(i));