The Tor Browser: dom/encoding/test/unit/test_utf.js@925c144e1f1f (annotated)

dom/encoding/test/unit/test_utf.js@925c144e1f1f (annotated)

dom/encoding/test/unit/test_utf.js

Fri, 16 Jan 2015 18:13:44 +0100

author: Michael Schloh von Bennewitz <michael@schloh.com>
date: Fri, 16 Jan 2015 18:13:44 +0100
branch: TOR_BUG_9701
changeset 14: 925c144e1f1f
permissions: -rw-r--r--

Integrate suggestion from review to improve consistency with existing code.

 // NOTE: Requires testharness.js
 // http://www.w3.org/2008/webapps/wiki/Harness
 // Extension to testharness.js API which avoids logging enormous strings
 // on a coding failure.
 function assert_string_equals(actual, expected, description) {
   // short circuit success case
   if (actual === expected) {
     assert_true(true, description + ": <actual> === <expected>");
     return;
   }
   // length check
   assert_equals(actual.length, expected.length,
                 description + ": string lengths")
   var i, a, b;
   for (i = 0; i < actual.length; i++) {
     a = actual.charCodeAt(i);
     b = expected.charCodeAt(i);
     if (a !== b)
       assert_true(false,
                   description +
                   ": code unit " + i.toString() + " unequal: " +
                   cpname(a) + " != " + cpname(b)); // doesn't return
   }
   // It should be impossible to get here, because the initial
   // comparison failed, so either the length comparison or the
   // codeunit-by-codeunit comparison should also fail.
   assert_true(false, description + ": failed to detect string difference");
 }
 // Inspired by:
 // http://ecmanaut.blogspot.com/2006/07/encoding-decoding-utf8-in-javascript.html
 function encode_utf8(string) {
   var utf8 = unescape(encodeURIComponent(string));
   var octets = new Uint8Array(utf8.length), i;
   for (i = 0; i < utf8.length; i += 1) {
     octets[i] = utf8.charCodeAt(i);
   }
   return octets;
 }
 function decode_utf8(octets) {
   var utf8 = String.fromCharCode.apply(null, octets);
   return decodeURIComponent(escape(utf8));
 }
 // Helpers for test_utf_roundtrip.
 function cpname(n) {
   if (n+0 !== n)
     return n.toString();
   var w = (n <= 0xFFFF) ? 4 : 6;
   return 'U+' + ('000000' + n.toString(16).toUpperCase()).slice(-w);
 }
 function genblock(from, len) {
   var i, j, point, offset;
   var size, block;
   // determine size required:
   //    1 unit   for each point from U+000000 through U+00D7FF
   //    0 units                      U+00D800 through U+00DFFF
   //    1 unit                       U+00E000 through U+00FFFF
   //    2 units                      U+010000 through U+10FFFF
   function overlap(min1, max1, min2, max2) {
     return Math.max(0, Math.min(max1, max2) - Math.max(min1, min2));
   }
   size = (overlap(from, from+len, 0x000000, 0x00D800) +
           overlap(from, from+len, 0x00E000, 0x010000) +
           overlap(from, from+len, 0x010000, 0x110000)*2);
   block = new Uint16Array(size);
   for (i = 0, j = 0; i < len; i++) {
     point = from + i;
     if (0xD800 <= point && point <= 0xDFFF)
       continue;
     else if (point <= 0xFFFF)
       block[j++] = point;
     else {
       offset = point - 0x10000;
       block[j++] = 0xD800 + (offset >> 10);
       block[j++] = 0xDC00 + (offset & 0x3FF);
     }
   }
   return String.fromCharCode.apply(null, block);
 }
 function test_utf_roundtrip () {
   var MIN_CODEPOINT = 0;
   var MAX_CODEPOINT = 0x10FFFF;
   var BLOCK_SIZE = 0x1000;
   var block, block_tag, i, j, encoded, decoded, exp_encoded, exp_decoded;
   var TE_U16LE = new TextEncoder("UTF-16LE");
   var TD_U16LE = new TextDecoder("UTF-16LE");
   var TE_U16BE = new TextEncoder("UTF-16BE");
   var TD_U16BE = new TextDecoder("UTF-16BE");
   var TE_U8    = new TextEncoder("UTF-8");
   var TD_U8    = new TextDecoder("UTF-8");
   for (i = MIN_CODEPOINT; i < MAX_CODEPOINT; i += BLOCK_SIZE) {
     block_tag = cpname(i) + " - " + cpname(i + BLOCK_SIZE - 1);
     block = genblock(i, BLOCK_SIZE);
     // test UTF-16LE, UTF-16BE, and UTF-8 encodings against themselves
     encoded = TE_U16LE.encode(block);
     decoded = TD_U16LE.decode(encoded);
     assert_string_equals(block, decoded, "UTF-16LE round trip " + block_tag);
     encoded = TE_U16BE.encode(block);
     decoded = TD_U16BE.decode(encoded);
     assert_string_equals(block, decoded, "UTF-16BE round trip " + block_tag);
     encoded = TE_U8.encode(block);
     decoded = TD_U8.decode(encoded);
     assert_string_equals(block, decoded, "UTF-8 round trip " + block_tag);
     // test TextEncoder(UTF-8) against the older idiom
     exp_encoded = encode_utf8(block);
     assert_array_equals(encoded, exp_encoded,
                         "UTF-8 reference encoding " + block_tag);
     exp_decoded = decode_utf8(exp_encoded);
     assert_string_equals(decoded, exp_decoded,
                          "UTF-8 reference decoding " + block_tag);
   }
 }
 function test_utf_samples () {
   // z, cent, CJK water, G-Clef, Private-use character
   var sample = "z\xA2\u6C34\uD834\uDD1E\uDBFF\uDFFD";
   var cases = [
     { encoding: "utf-8",
       expected: [0x7A, 0xC2, 0xA2, 0xE6, 0xB0, 0xB4, 0xF0, 0x9D, 0x84, 0x9E, 0xF4, 0x8F, 0xBF, 0xBD] },
     { encoding: "utf-16le",
       expected: [0x7A, 0x00, 0xA2, 0x00, 0x34, 0x6C, 0x34, 0xD8, 0x1E, 0xDD, 0xFF, 0xDB, 0xFD, 0xDF] },
     { encoding: "utf-16",
       expected: [0x7A, 0x00, 0xA2, 0x00, 0x34, 0x6C, 0x34, 0xD8, 0x1E, 0xDD, 0xFF, 0xDB, 0xFD, 0xDF] },
     { encoding: "utf-16be",
       expected: [0x00, 0x7A, 0x00, 0xA2, 0x6C, 0x34, 0xD8, 0x34, 0xDD, 0x1E, 0xDB, 0xFF, 0xDF, 0xFD] }
   ];
   cases.forEach(
     function(t) {
       var encoded = new TextEncoder(t.encoding).encode(sample);
       assert_array_equals(encoded, t.expected,
                           "expected equal encodings - " + t.encoding);
       var decoded = new TextDecoder(t.encoding)
                         .decode(new Uint8Array(t.expected));
       assert_equals(decoded, sample,
                     "expected equal decodings - " + t.encoding);
     });
 }
 test(test_utf_samples,
      "UTF-8, UTF-16LE, UTF-16BE - Encode/Decode - reference sample");
 test(test_utf_roundtrip,
      "UTF-8, UTF-16LE, UTF-16BE - Encode/Decode - full roundtrip and "+
      "agreement with encode/decodeURIComponent");