1 files changed, 143 insertions, 0 deletions
diff --git a/data/extensions/uBlock0@raymondhill.net/js/base64-custom.js b/data/extensions/uBlock0@raymondhill.net/js/base64-custom.js
new file mode 100644
index 0000000..9d15d71
--- /dev/null
+++ b/data/extensions/uBlock0@raymondhill.net/js/base64-custom.js
@@ -0,0 +1,143 @@
+/*******************************************************************************
+
+    uBlock Origin - a comprehensive, efficient content blocker
+    Copyright (C) 2014-present Raymond Hill
+
+    This program is free software: you can redistribute it and/or modify
+    it under the terms of the GNU General Public License as published by
+    the Free Software Foundation, either version 3 of the License, or
+    (at your option) any later version.
+
+    This program is distributed in the hope that it will be useful,
+    but WITHOUT ANY WARRANTY; without even the implied warranty of
+    MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+    GNU General Public License for more details.
+
+    You should have received a copy of the GNU General Public License
+    along with this program.  If not, see {http://www.gnu.org/licenses/}.
+
+    Home: https://github.com/gorhill/uBlock
+*/
+
+/******************************************************************************/
+
+// Custom base64 codecs. These codecs are meant to encode/decode typed arrays
+// to/from strings.
+
+// https://github.com/uBlockOrigin/uBlock-issues/issues/461
+//   Provide a fallback encoding for Chromium 59 and less by issuing a plain
+//   JSON string. The fallback can be removed once min supported version is
+//   above 59.
+
+// TODO: rename µBlock.base64 to µBlock.SparseBase64, now that
+//       µBlock.DenseBase64 has been introduced.
+// TODO: Should no longer need to test presence of TextEncoder/TextDecoder.
+
+const valToDigit = new Uint8Array(64);
+const digitToVal = new Uint8Array(128);
+{
+    const chars = '0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz@%';
+    for ( let i = 0, n = chars.length; i < n; i++ ) {
+        const c = chars.charCodeAt(i);
+        valToDigit[i] = c;
+        digitToVal[c] = i;
+    }
+}
+
+// The dense base64 codec is best for typed buffers which values are
+// more random. For example, buffer contents as a result of compression
+// contain less repetitive values and thus the content is more
+// random-looking.
+
+// TODO: Investigate that in Firefox, creating a new Uint8Array from the
+//       ArrayBuffer fails, the content of the resulting Uint8Array is
+//       non-sensical. WASM-related?
+
+export const denseBase64 = {
+    magic: 'DenseBase64_1',
+
+    encode: function(input) {
+        const m = input.length % 3;
+        const n = input.length - m;
+        let outputLength = n / 3 * 4;
+        if ( m !== 0 ) {
+            outputLength += m + 1;
+        }
+        const output = new Uint8Array(outputLength);
+        let j = 0;
+        for ( let i = 0; i < n; i += 3) {
+            const i1 = input[i+0];
+            const i2 = input[i+1];
+            const i3 = input[i+2];
+            output[j+0] = valToDigit[                     i1 >>> 2];
+            output[j+1] = valToDigit[i1 << 4 & 0b110000 | i2 >>> 4];
+            output[j+2] = valToDigit[i2 << 2 & 0b111100 | i3 >>> 6];
+            output[j+3] = valToDigit[i3      & 0b111111           ];
+            j += 4;
+        }
+        if ( m !== 0 ) {
+            const i1 = input[n];
+            output[j+0] = valToDigit[i1 >>> 2];
+            if ( m === 1 ) {    // 1 value
+                output[j+1] = valToDigit[i1 << 4 & 0b110000];
+            } else {            // 2 values
+                const i2 = input[n+1];
+                output[j+1] = valToDigit[i1 << 4 & 0b110000 | i2 >>> 4];
+                output[j+2] = valToDigit[i2 << 2 & 0b111100           ];
+            }
+        }
+        const textDecoder = new TextDecoder();
+        const b64str = textDecoder.decode(output);
+        return this.magic + b64str;
+    },
+
+    decode: function(instr, arrbuf) {
+        if ( instr.startsWith(this.magic) === false ) {
+            throw new Error('Invalid µBlock.denseBase64 encoding');
+        }
+        const outputLength = this.decodeSize(instr);
+        const outbuf = arrbuf instanceof ArrayBuffer === false
+            ? new Uint8Array(outputLength)
+            : new Uint8Array(arrbuf);
+        const inputLength = instr.length - this.magic.length;
+        let i = this.magic.length;
+        let j = 0;
+        const m = inputLength & 3;
+        const n = i + inputLength - m;
+        while ( i < n ) {
+            const i1 = digitToVal[instr.charCodeAt(i+0)];
+            const i2 = digitToVal[instr.charCodeAt(i+1)];
+            const i3 = digitToVal[instr.charCodeAt(i+2)];
+            const i4 = digitToVal[instr.charCodeAt(i+3)];
+            i += 4;
+            outbuf[j+0] = i1 << 2              | i2 >>> 4;
+            outbuf[j+1] = i2 << 4 & 0b11110000 | i3 >>> 2;
+            outbuf[j+2] = i3 << 6 & 0b11000000 | i4;
+            j += 3;
+        }
+        if ( m !== 0 ) {
+            const i1 = digitToVal[instr.charCodeAt(i+0)];
+            const i2 = digitToVal[instr.charCodeAt(i+1)];
+            outbuf[j+0] = i1 << 2 | i2 >>> 4;
+            if ( m === 3 ) {
+                const i3 = digitToVal[instr.charCodeAt(i+2)];
+                outbuf[j+1] = i2 << 4 & 0b11110000 | i3 >>> 2;
+            }
+        }
+        return outbuf;
+    },
+
+    decodeSize: function(instr) {
+        if ( instr.startsWith(this.magic) === false ) { return 0; }
+        const inputLength = instr.length - this.magic.length;
+        const m = inputLength & 3;
+        const n = inputLength - m;
+        let outputLength = (n >>> 2) * 3;
+        if ( m !== 0 ) {
+            outputLength += m - 1;
+        }
+        return outputLength;
+    },
+};
+
+/******************************************************************************/