diff options
Diffstat (limited to 'src/corelib/codecs')
| -rw-r--r-- | src/corelib/codecs/qutfcodec.cpp | 44 |
1 files changed, 36 insertions, 8 deletions
diff --git a/src/corelib/codecs/qutfcodec.cpp b/src/corelib/codecs/qutfcodec.cpp index c0f26ad803..f16144771f 100644 --- a/src/corelib/codecs/qutfcodec.cpp +++ b/src/corelib/codecs/qutfcodec.cpp @@ -254,7 +254,20 @@ QByteArray QUtf8::convertFromUnicode(const QChar *uc, int len, QTextCodec::Conve QString QUtf8::convertToUnicode(const char *chars, int len) { - QString result(len + 1, Qt::Uninitialized); // worst case + // UTF-8 to UTF-16 always needs the exact same number of words or less: + // UTF-8 UTF-16 + // 1 byte 1 word + // 2 bytes 1 word + // 3 bytes 1 word + // 4 bytes 2 words (one surrogate pair) + // That is, we'll use the full buffer if the input is US-ASCII (1-byte UTF-8), + // half the buffer for U+0080-U+07FF text (e.g., Greek, Cyrillic, Arabic) or + // non-BMP text, and one third of the buffer for U+0800-U+FFFF text (e.g, CJK). + // + // The table holds for invalid sequences too: we'll insert one replacement char + // per invalid byte. + QString result(len, Qt::Uninitialized); + ushort *dst = reinterpret_cast<ushort *>(const_cast<QChar *>(result.constData())); const uchar *src = reinterpret_cast<const uchar *>(chars); const uchar *end = src + len; @@ -299,7 +312,18 @@ QString QUtf8::convertToUnicode(const char *chars, int len, QTextCodec::Converte int res; uchar ch = 0; - QString result(need + len + 1, Qt::Uninitialized); // worst case + // See above for buffer requirements for stateless decoding. However, that + // fails if the state is not empty. The following situations can add to the + // requirements: + // state contains chars starts with requirement + // 1 of 2 bytes valid continuation 0 + // 2 of 3 bytes same 0 + // 3 bytes of 4 same +1 (need to insert surrogate pair) + // 1 of 2 bytes invalid continuation +1 (need to insert replacement and restart) + // 2 of 3 bytes same +1 (same) + // 3 of 4 bytes same +1 (same) + QString result(need + len + 1, Qt::Uninitialized); + ushort *dst = reinterpret_cast<ushort *>(const_cast<QChar *>(result.constData())); const uchar *src = reinterpret_cast<const uchar *>(chars); const uchar *end = src + len; @@ -322,15 +346,17 @@ QString QUtf8::convertToUnicode(const char *chars, int len, QTextCodec::Converte const uchar *begin = &remainingCharsData[1]; res = QUtf8Functions::fromUtf8<QUtf8BaseTraits>(remainingCharsData[0], dst, begin, static_cast<const uchar *>(remainingCharsData) + remainingCharsCount + newCharsToCopy); - if (res == QUtf8BaseTraits::EndOfString) { + if (res == QUtf8BaseTraits::Error || (res == QUtf8BaseTraits::EndOfString && len == 0)) { + // special case for len == 0: + // if we were supplied an empty string, terminate the previous, unfinished sequence with error + ++invalid; + *dst++ = replacement; + } else if (res == QUtf8BaseTraits::EndOfString) { // if we got EndOfString again, then there were too few bytes in src; // copy to our state and return state->remainingChars = remainingCharsCount + newCharsToCopy; memcpy(&state->state_data[0], remainingCharsData, state->remainingChars); return QString(); - } else if (res == QUtf8BaseTraits::Error) { - ++invalid; - *dst++ = replacement; } else if (!headerdone && res >= 0) { // eat the UTF-8 BOM headerdone = true; @@ -339,8 +365,10 @@ QString QUtf8::convertToUnicode(const char *chars, int len, QTextCodec::Converte } // adjust src now that we have maybe consumed a few chars - //Q_ASSERT(res > remainingCharsCount) - src += res - remainingCharsCount; + if (res >= 0) { + Q_ASSERT(res > remainingCharsCount); + src += res - remainingCharsCount; + } } } |