@esutils/dns-packet/dist/cjs/reader.js

A minimal dns-packet library that implemented in `typescript`

"use strict";
/* eslint-disable no-bitwise */
Object.defineProperty(exports, "__esModule", { value: true });
exports.BufferReader = void 0;
function p(a) {
    let n = 0;
    const f = a.length - 1;
    for (let i = f; i >= 0; i -= 1) {
        if (a[f - i])
            n += 2 ** i;
    }
    return n;
}
/**
 * [Reader description]
 * @param {[type]} buffer [description]
 * @param {[type]} offset [description]
 */
class BufferReader {
    buffer;
    offset;
    constructor(buffer, offset) {
        this.buffer = buffer;
        this.offset = offset || 0;
    }
    /**
     * [read description]
     * @param  {[type]} buffer [description]
     * @param  {[type]} offset [description]
     * @param  {[type]} length [description]
     * @return {[type]}        [description]
     */
    static read(buffer, offset, length) {
        let a = [];
        let c = Math.ceil(length / 8);
        let l = Math.floor(offset / 8);
        const m = offset % 8;
        function t(n) {
            const r = [0, 0, 0, 0, 0, 0, 0, 0];
            for (let i = 7; i >= 0; i -= 1) {
                r[7 - i] = n & 2 ** i ? 1 : 0;
            }
            a = a.concat(r);
        }
        const view = new DataView(buffer.buffer, buffer.byteOffset, buffer.byteLength);
        while (c--)
            t(view.getUint8(l++));
        return p(a.slice(m, m + length));
    }
    /**
     * [read description]
     * @param  {[type]} size [description]
     * @return {[type]}      [description]
     */
    read(size) {
        const val = BufferReader.read(this.buffer, this.offset, size);
        this.offset += size;
        return val;
    }
}
exports.BufferReader = BufferReader;
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