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helpers.foldline: do not insert spaces between the high and low UTF-16 surrogates #439

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Merged
merged 1 commit into from
Aug 1, 2021
Merged

helpers.foldline: do not insert spaces between the high and low UTF-16 surrogates #439

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19 changes: 15 additions & 4 deletions lib/ical/helpers.js
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Original file line number Diff line number Diff line change
Expand Up @@ -287,11 +287,22 @@ ICAL.helpers = {
*/
foldline: function foldline(aLine) {
var result = "";
var line = aLine || "";

var line = aLine || "", pos = 0, line_length = 0;
//pos counts position in line for the UTF-16 presentation
//line_length counts the bytes for the UTF-8 presentation
while (line.length) {
result += ICAL.newLineChar + " " + line.substr(0, ICAL.foldLength);
line = line.substr(ICAL.foldLength);
var cp = line.codePointAt(pos);
if (cp < 128) ++line_length;
else if (cp < 2048) line_length += 2;//needs 2 UTF-8 bytes
else if (cp < 65536) line_length += 3;
else line_length += 4; //cp is less than 1114112
if (line_length < ICAL.foldLength + 1)
pos += cp > 65535 ? 2 : 1;
else {
result += ICAL.newLineChar + " " + line.substring(0, pos);
line = line.substring(pos);
pos = line_length = 0;
}
}
return result.substr(ICAL.newLineChar.length + 1);
},
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6 changes: 6 additions & 0 deletions test/stringify_test.js
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Expand Up @@ -113,6 +113,12 @@ suite('ICAL.stringify', function() {
assert.equal(ICAL.stringify.property(subject.toJSON(), ICAL.design.icalendar, false), "DESCRIPTION:foo" + N + "bar");
assert.equal(ICAL.stringify.property(subject.toJSON(), ICAL.design.icalendar, true), "DESCRIPTION:foobar");

var utf16_muscle = '\uD83D\uDCAA'; //in UTF-8 this is F0 DF 92 AA. If space/new line is inserted between the surrogates, then the JS Engine substitutes each stand-alone surrogate with REPLACEMENT CHARACTER 0xEF 0xBF 0xBD
subject.setValue(utf16_muscle);
assert.equal(ICAL.stringify.property(subject.toJSON(), ICAL.design.icalendar, false), "DESCRIPTION:" + N + utf16_muscle);//verify new line is after ':', as otherwise the whole line is longer than ICAL.foldLength
subject.setValue('aa' + utf16_muscle + utf16_muscle + 'a' + utf16_muscle + utf16_muscle);
assert.equal(ICAL.stringify.property(subject.toJSON(), ICAL.design.icalendar, false), "DESCRIPTION:aa" + N + utf16_muscle + utf16_muscle + 'a' + utf16_muscle + N + utf16_muscle);//verify that the utf16_muscle is moved as whole to a new line as it is 4 UTF-8 bytes

ICAL.foldLength = oldLength;
});
});
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