@node-dlc/wire
Version:
Lightning Network Wire Protocol
66 lines • 2.17 kB
JavaScript
;
Object.defineProperty(exports, "__esModule", { value: true });
exports.ipv6StringFromBuffer = void 0;
/**
* Converts a buffer containing an IPv6 address into string notation.
* String notation consists of 8 sets of 16-bits each. Each group is
* written as four hexadecimal values separated by colons (:). This method
* follows RFC 5952 shortening.
*
* @remarks
* RFC 5952 https://tools.ietf.org/html/rfc5952
*
* The following shortening rules are applied:
* 1. Leading zeros are shorted as much as possible
* 2. Zero compression is from left to right and
* 3. Addresses are returned in lowercase.
*/
function ipv6StringFromBuffer(buffer) {
const sections = getHexSections(buffer);
const result = sectionsToString(sections);
return result;
}
exports.ipv6StringFromBuffer = ipv6StringFromBuffer;
function getHexSections(buffer) {
const bytesPerSection = 2;
const sections = [];
for (let i = 0; i < buffer.length; i += bytesPerSection) {
let section = buffer.slice(i, i + bytesPerSection).toString('hex');
section = discardLeadingZeros(section);
sections.push(section);
}
return sections;
}
function discardLeadingZeros(section) {
return section.replace(/^0+/g, '');
}
function sectionsToString(sections) {
let result = '';
let hasCollapsed = false;
for (const s of sections) {
// alrerady in collapse state, no-op
if (result.endsWith('::') && s === '')
continue;
// collapse zero section
if (s === '' && !hasCollapsed) {
hasCollapsed = true;
if (result === '')
result += '::';
else
result += ':';
continue;
}
// we have a zero, but already collapsed so we need to mark as zero
if (hasCollapsed && s === '') {
result += '0:';
continue;
}
// normal condition
result += s + ':';
}
// remove trailing except with ending with ::;
if (!result.endsWith('::'))
result = result.slice(0, -1);
return result;
}
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