@ethereumjs/mpt
Version:
Implementation of the modified merkle patricia tree as specified in Ethereum's yellow paper.
79 lines • 1.91 kB
JavaScript
;
Object.defineProperty(exports, "__esModule", { value: true });
exports.bytesToNibbles = bytesToNibbles;
exports.nibblesTypeToPackedBytes = nibblesTypeToPackedBytes;
exports.nibblesCompare = nibblesCompare;
exports.matchingNibbleLength = matchingNibbleLength;
/**
* Converts a bytes to a nibble array.
* @private
* @param key
*/
function bytesToNibbles(key) {
const nibbles = [];
for (let i = 0; i < key.length; i++) {
let q = i * 2;
nibbles[q] = key[i] >> 4;
++q;
nibbles[q] = key[i] % 16;
}
return nibbles;
}
/**
* Converts a nibble array into bytes.
* @private
* @param arr - Nibble array
*/
function nibblesTypeToPackedBytes(arr) {
const buf = new Uint8Array(arr.length / 2);
for (let i = 0; i < buf.length; i++) {
let q = i * 2;
buf[i] = (arr[q] << 4) + arr[++q];
}
return buf;
}
/**
* Compare two nibble array.
* * `0` is returned if `n2` === `n1`.
* * `1` is returned if `n2` > `n1`.
* * `-1` is returned if `n2` < `n1`.
* @param n1 - Nibble array
* @param n2 - Nibble array
*/
function nibblesCompare(n1, n2) {
const cmpLength = Math.min(n1.length, n2.length);
let res = 0;
for (let i = 0; i < cmpLength; i++) {
if (n1[i] < n2[i]) {
res = -1;
break;
}
else if (n1[i] > n2[i]) {
res = 1;
break;
}
}
if (res === 0) {
if (n1.length < n2.length) {
res = -1;
}
else if (n1.length > n2.length) {
res = 1;
}
}
return res;
}
/**
* Returns the number of in order matching nibbles of two give nibble arrays.
* @private
* @param nib1
* @param nib2
*/
function matchingNibbleLength(nib1, nib2) {
let i = 0;
while (nib1[i] === nib2[i] && nib1.length > i) {
i++;
}
return i;
}
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