identify-media/dist/lib/makeHash.js

Analyse file path and content to make search criteria for media APIs

"use strict";
Object.defineProperty(exports, "__esModule", { value: true });
exports.makeHash = void 0;
const initBlock = (size) => {
    let temp = size;
    const longs = [];
    for (let i = 0; i < 8; i++) {
        longs[i] = temp & 255;
        temp = temp >> 8;
    }
    return longs;
};
const processChunk = (chunk, init) => {
    return chunk.split('').reduce((result, current, index) => {
        const idx = (index + 8) % 8;
        return result.slice(0, idx).concat(result[idx] + current.charCodeAt(0)).concat(result.slice(idx + 1));
    }, init);
};
const longsToBin = (longs) => {
    return longs.reduce((result, current) => {
        const sum = current + result.overflow;
        const overflow = sum >> 8;
        return {
            normalized: result.normalized.concat(sum & 255),
            overflow
        };
    }, { normalized: [], overflow: 0 }).normalized;
};
const bin2hex = (longs) => {
    const hexString = '0123456789abcdef';
    return longsToBin(longs).reverse().reduce((result, current) => {
        return result + hexString.charAt(current >> 4 & 15) + hexString.charAt(current & 15);
    }, '');
};
const makeHash = (size, firstChunk, secondChunk) => {
    return firstChunk
        .then((chunk) => processChunk(chunk, initBlock(size)))
        .then((longs) => secondChunk.then((chunk) => processChunk(chunk, longs)))
        .then(bin2hex);
};
exports.makeHash = makeHash;
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