On Sunday 02 September 2012 23:10:18 Konstantin Tokarev wrote:
> Hi all,
>
> When building Qt 5 on big endian host (PPC) I've found moc breaking on Qt
> classes containing Q_PLUGIN_METADATA with
>
> ASSERT: "idx >= 0 && idx < s" in file
> ../../../include/QtCore/../../src/corelib/tools/qvarlengtharray.h, line 111
>
> It turned out to be a fault of QJsonPrivate::Parser::parseObject which has
> different code for handling of big endian and little endian cases:
>
> if (parsedObject.offsets.size()) {
> int tableSize = parsedObject.offsets.size()*sizeof(uint);
^^^^^^^^^^^^^
The error is there: one should multiply tableSize by sizeof(uint) only if one
do a memcpy.
> table = reserveSpace(tableSize);
> #if Q_BYTE_ORDER == Q_LITTLE_ENDIAN
> memcpy(data + table, parsedObject.offsets.constData(), tableSize);
> #else
> offset *o = (offset *)(data + table);
> for (int i = 0; i < tableSize; ++i)
> o[i] = parsedObject.offsets[i];
>
> #endif
> }
>
> Could anyone explain why memcpy cannot be used for big endian case here?
I guess that's because the offsets needs to be stored in little endian.
offset is a typedef to a class that has an assignement operator which swap the
bytes.
--
Olivier
Woboq - Qt services and support - http://woboq.com
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