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UTF16 buffer boundary XALANJ-2725 #166

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UTF16 buffer boundary XALANJ-2725 #166

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490b5ab
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maxfortun Jan 24, 2024
e92e170
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maxfortun Jan 24, 2024
0006abf
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maxfortun Jan 24, 2024
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43 changes: 32 additions & 11 deletions serializer/src/main/java/org/apache/xml/serializer/ToStream.java
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Original file line number Diff line number Diff line change
Expand Up @@ -175,6 +175,10 @@ abstract public class ToStream extends SerializerBase
*/
private boolean m_expandDTDEntities = true;

/**
* Track multibyte character in order to serialize when the whole byte sequence is available.
*/
private char m_highUTF16Surrogate = 0;

/**
* Default constructor
Expand Down Expand Up @@ -1595,23 +1599,40 @@ else if (m_encodingInfo.isInEncoding(ch)) {
// not in the normal ASCII range, we also
// just leave it get added on to the clean characters
}
else if (Encodings.isHighUTF16Surrogate(ch) && i < end-1 && Encodings.isLowUTF16Surrogate(chars[i+1])) {
// So, this is a (valid) surrogate pair
if (! m_encodingInfo.isInEncoding(ch, chars[i+1])) {
int codepoint = Encodings.toCodePoint(ch, chars[i+1]);
writeOutCleanChars(chars, i, lastDirtyCharProcessed);
writer.write("&#");
writer.write(Integer.toString(codepoint));
writer.write(';');
lastDirtyCharProcessed = i+1;
}
i++; // skip the low surrogate, too
else if (Encodings.isHighUTF16Surrogate(ch)) {
// Store for later processing. We may be at the end of a buffer,
// and must wait till low surrogate arrives
// before we can do anything with this.
writeOutCleanChars(chars, i, lastDirtyCharProcessed);
m_highUTF16Surrogate = ch;
lastDirtyCharProcessed = i;
}
else if (m_highUTF16Surrogate != 0 && Encodings.isLowUTF16Surrogate(ch)) {
// The complete utf16 byte sequence is now available and may be serialized.
if (! m_encodingInfo.isInEncoding(m_highUTF16Surrogate, ch)) {
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@maxfortun maxfortun Jan 24, 2024

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1602: If ch is high surrogate, dump clean chars and retain ch. This works within the same buffer or across buffer boundaries
1610: if we have a retained high surrogate and ch is a valid low surrogate, we have 2 use cases.
1. encoding doesn't support the multibyte char, escape entity.
2. encoding does support the multibyte char, output chars as is.

int codepoint = Encodings.toCodePoint(m_highUTF16Surrogate, ch);
writer.write("&#");
writer.write(Integer.toString(codepoint));
writer.write(';');
} else {
writer.write(m_highUTF16Surrogate);
writer.write(ch);
}
lastDirtyCharProcessed = i;
m_highUTF16Surrogate = 0;
}
else {
// This is a fallback plan, we get here if the
// encoding doesn't contain ch and it's not part
// of a surrogate pair
// The right thing is to write out an entity
if(m_highUTF16Surrogate != 0) {
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@maxfortun maxfortun Jan 24, 2024

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This is probably not a valid scenario and should throw an error. I am not certain what is the correct way to address a situation where we have seen a high surrogate not followed by a low one.

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@maxfortun maxfortun Jan 24, 2024

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Btw, I did encounter this scenario, that's why I coded this. But in theory this should not be happening.

writer.write("&#");
writer.write(Integer.toString(m_highUTF16Surrogate));
writer.write(';');
m_highUTF16Surrogate = 0;
}

writeOutCleanChars(chars, i, lastDirtyCharProcessed);
writer.write("&#");
writer.write(Integer.toString(ch));
Expand Down