96 lines
2.5 KiB
JavaScript
96 lines
2.5 KiB
JavaScript
/*
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* Copyright 2013 Mozilla Foundation
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*
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* Licensed under the Apache License, Version 2.0 (the "License");
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* you may not use this file except in compliance with the License.
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* You may obtain a copy of the License at
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*
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* http://www.apache.org/licenses/LICENSE-2.0
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*
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* Unless required by applicable law or agreed to in writing, software
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* distributed under the License is distributed on an "AS IS" BASIS,
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* WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
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* See the License for the specific language governing permissions and
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* limitations under the License.
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*/
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const base64alphabet =
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"ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/=";
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function decodeFontData(base64) {
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const result = [];
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let bits = 0,
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bitsLength = 0;
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for (let i = 0, ii = base64.length; i < ii; i++) {
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const ch = base64[i];
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if (ch <= " ") {
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continue;
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}
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const index = base64alphabet.indexOf(ch);
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if (index < 0) {
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throw new Error("Invalid character");
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}
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if (index >= 64) {
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break;
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}
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bits = (bits << 6) | index;
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bitsLength += 6;
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if (bitsLength >= 8) {
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bitsLength -= 8;
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const code = (bits >> bitsLength) & 0xff;
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result.push(code);
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}
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}
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return new Uint8Array(result);
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}
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function encodeFontData(data) {
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let buffer = "";
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let i, n;
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for (i = 0, n = data.length; i < n; i += 3) {
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const b1 = data[i] & 0xff;
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const b2 = data[i + 1] & 0xff;
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const b3 = data[i + 2] & 0xff;
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const d1 = b1 >> 2,
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d2 = ((b1 & 3) << 4) | (b2 >> 4);
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const d3 = i + 1 < n ? ((b2 & 0xf) << 2) | (b3 >> 6) : 64;
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const d4 = i + 2 < n ? b3 & 0x3f : 64;
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buffer +=
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base64alphabet.charAt(d1) +
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base64alphabet.charAt(d2) +
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base64alphabet.charAt(d3) +
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base64alphabet.charAt(d4);
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}
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return buffer;
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}
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function ttx(data, callback) {
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const xhr = new XMLHttpRequest();
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xhr.open("POST", "/ttx");
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const encodedData = encodeFontData(data);
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xhr.setRequestHeader("Content-type", "text/plain");
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xhr.setRequestHeader("Content-length", encodedData.length);
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xhr.onreadystatechange = function getPdfOnreadystatechange(e) {
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if (xhr.readyState === 4) {
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if (xhr.status === 200) {
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callback(xhr.responseText);
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} else {
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callback("<error>Transport error: " + xhr.statusText + "</error>");
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}
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}
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};
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xhr.send(encodedData);
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}
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function verifyTtxOutput(output) {
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const m = /^<error>(.*?)<\/error>/.exec(output);
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if (m) {
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throw m[1];
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}
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}
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export { decodeFontData, encodeFontData, ttx, verifyTtxOutput };
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