98 lines
3.6 KiB
JavaScript
98 lines
3.6 KiB
JavaScript
// @ts-nocheck
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// Source: https://github.com/beatgammit/base64-js/blob/88957c9943c7e2a0f03cdf73e71d579e433627d3/index.js
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const lookup = [];
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const revLookup = [];
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const Arr = typeof Uint8Array === "undefined" ? Array : Uint8Array;
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const code = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/";
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for (let i = 0, len = code.length; i < len; ++i) {
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lookup[i] = code[i];
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revLookup[code.charCodeAt(i)] = i;
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}
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// Support decoding URL-safe base64 strings, as Node.js does.
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// See: https://en.wikipedia.org/wiki/Base64#URL_applications
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revLookup["-".charCodeAt(0)] = 62;
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revLookup["_".charCodeAt(0)] = 63;
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function getLens(b64) {
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const len = b64.length;
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if (len % 4 > 0) {
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throw new Error("Invalid string. Length must be a multiple of 4");
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}
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// Trim off extra bytes after placeholder bytes are found
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// See: https://github.com/beatgammit/base64-js/issues/42
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let validLen = b64.indexOf("=");
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if (validLen === -1) {
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validLen = len;
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}
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const placeHoldersLen = validLen === len ? 0 : 4 - validLen % 4;
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return [validLen, placeHoldersLen];
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}
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// base64 is 4/3 + up to two characters of the original data
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export function byteLength(b64) {
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const lens = getLens(b64);
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const validLen = lens[0];
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const placeHoldersLen = lens[1];
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return (validLen + placeHoldersLen) * 3 / 4 - placeHoldersLen;
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}
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function _byteLength(b64, validLen, placeHoldersLen) {
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return (validLen + placeHoldersLen) * 3 / 4 - placeHoldersLen;
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}
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export function toByteArray(b64) {
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let tmp;
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const lens = getLens(b64);
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const validLen = lens[0];
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const placeHoldersLen = lens[1];
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const arr = new Arr(_byteLength(b64, validLen, placeHoldersLen));
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let curByte = 0;
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// if there are placeholders, only get up to the last complete 4 chars
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const len = placeHoldersLen > 0 ? validLen - 4 : validLen;
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let i;
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for (i = 0; i < len; i += 4) {
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tmp = revLookup[b64.charCodeAt(i)] << 18 | revLookup[b64.charCodeAt(i + 1)] << 12 | revLookup[b64.charCodeAt(i + 2)] << 6 | revLookup[b64.charCodeAt(i + 3)];
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arr[curByte++] = tmp >> 16 & 255;
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arr[curByte++] = tmp >> 8 & 255;
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arr[curByte++] = tmp & 255;
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}
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if (placeHoldersLen === 2) {
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tmp = revLookup[b64.charCodeAt(i)] << 2 | revLookup[b64.charCodeAt(i + 1)] >> 4;
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arr[curByte++] = tmp & 255;
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}
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if (placeHoldersLen === 1) {
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tmp = revLookup[b64.charCodeAt(i)] << 10 | revLookup[b64.charCodeAt(i + 1)] << 4 | revLookup[b64.charCodeAt(i + 2)] >> 2;
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arr[curByte++] = tmp >> 8 & 255;
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arr[curByte++] = tmp & 255;
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}
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return arr;
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}
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function tripletToBase64(num) {
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return lookup[num >> 18 & 63] + lookup[num >> 12 & 63] + lookup[num >> 6 & 63] + lookup[num & 63];
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}
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function encodeChunk(uint8, start, end) {
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let tmp;
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const output = [];
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for (let i = start; i < end; i += 3) {
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tmp = (uint8[i] << 16 & 16711680) + (uint8[i + 1] << 8 & 65280) + (uint8[i + 2] & 255);
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output.push(tripletToBase64(tmp));
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}
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return output.join("");
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}
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export function fromByteArray(uint8) {
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let tmp;
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const len = uint8.length;
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const extraBytes = len % 3;
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const parts = [];
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const maxChunkLength = 16383;
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// go through the array every three bytes, we'll deal with trailing stuff later
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for (let i = 0, len2 = len - extraBytes; i < len2; i += maxChunkLength) {
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parts.push(encodeChunk(uint8, i, i + maxChunkLength > len2 ? len2 : i + maxChunkLength));
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}
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// pad the end with zeros, but make sure to not forget the extra bytes
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if (extraBytes === 1) {
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tmp = uint8[len - 1];
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parts.push(lookup[tmp >> 2] + lookup[tmp << 4 & 63] + "==");
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} else if (extraBytes === 2) {
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tmp = (uint8[len - 2] << 8) + uint8[len - 1];
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parts.push(lookup[tmp >> 10] + lookup[tmp >> 4 & 63] + lookup[tmp << 2 & 63] + "=");
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}
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return parts.join("");
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}
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