91 lines
3.1 KiB
JavaScript
91 lines
3.1 KiB
JavaScript
"use strict";
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Object.defineProperty(exports, "__esModule", { value: true });
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exports.dataUriToBuffer = void 0;
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function base64ToArrayBuffer(base64) {
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const chars = 'ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/';
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const bytes = [];
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for (let i = 0; i < base64.length; i += 4) {
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const idx0 = chars.indexOf(base64.charAt(i));
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const idx1 = chars.indexOf(base64.charAt(i + 1));
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const idx2 = base64.charAt(i + 2) === '='
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? 0
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: chars.indexOf(base64.charAt(i + 2));
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const idx3 = base64.charAt(i + 3) === '='
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? 0
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: chars.indexOf(base64.charAt(i + 3));
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const bin0 = (idx0 << 2) | (idx1 >> 4);
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const bin1 = ((idx1 & 15) << 4) | (idx2 >> 2);
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const bin2 = ((idx2 & 3) << 6) | idx3;
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bytes.push(bin0);
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if (base64.charAt(i + 2) !== '=')
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bytes.push(bin1);
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if (base64.charAt(i + 3) !== '=')
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bytes.push(bin2);
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}
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const buffer = new ArrayBuffer(bytes.length);
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const view = new Uint8Array(buffer);
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view.set(bytes);
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return buffer;
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}
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function stringToBuffer(str) {
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// Create a buffer with length equal to the string length
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const buffer = new ArrayBuffer(str.length);
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// Create a view to manipulate the buffer content
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const view = new Uint8Array(buffer);
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// Iterate over the string and populate the buffer with ASCII codes
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for (let i = 0; i < str.length; i++) {
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view[i] = str.charCodeAt(i);
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}
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return buffer;
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}
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/**
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* Returns a `Buffer` instance from the given data URI `uri`.
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*
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* @param {String} uri Data URI to turn into a Buffer instance
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*/
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function dataUriToBuffer(uri) {
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uri = String(uri);
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if (!/^data:/i.test(uri)) {
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throw new TypeError('`uri` does not appear to be a Data URI (must begin with "data:")');
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}
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// strip newlines
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uri = uri.replace(/\r?\n/g, '');
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// split the URI up into the "metadata" and the "data" portions
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const firstComma = uri.indexOf(',');
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if (firstComma === -1 || firstComma <= 4) {
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throw new TypeError('malformed data: URI');
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}
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// remove the "data:" scheme and parse the metadata
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const meta = uri.substring(5, firstComma).split(';');
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let charset = '';
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let base64 = false;
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const type = meta[0] || 'text/plain';
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let typeFull = type;
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for (let i = 1; i < meta.length; i++) {
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if (meta[i] === 'base64') {
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base64 = true;
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}
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else if (meta[i]) {
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typeFull += `;${meta[i]}`;
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if (meta[i].indexOf('charset=') === 0) {
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charset = meta[i].substring(8);
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}
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}
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}
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// defaults to US-ASCII only if type is not provided
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if (!meta[0] && !charset.length) {
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typeFull += ';charset=US-ASCII';
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charset = 'US-ASCII';
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}
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// get the encoded data portion and decode URI-encoded chars
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const data = unescape(uri.substring(firstComma + 1));
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const buffer = base64 ? base64ToArrayBuffer(data) : stringToBuffer(data);
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return {
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type,
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typeFull,
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charset,
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buffer,
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};
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}
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exports.dataUriToBuffer = dataUriToBuffer;
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//# sourceMappingURL=index.js.map
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