[Oorexx-devel] RexxMutableBuffer, RexxBuffer, RexxString : some questions

[Jean-Louis F. <jfa...@gm...>]

Hi,

I saw those lines in RexxArray::toString :
RexxMutableBuffer *mutbuffer = ((RexxMutableBufferClass*)
TheMutableBufferClass)->newRexx(NULL, 0);
ProtectedObject p1(mutbuffer);
mutbuffer->append(_stringValue);
newString = mutbuffer->makeString();

Q1 :
I don't understand the implementation of RexxMutableBufferClass::newRexx.
There is a new with placement, but why allocate at the memory location of
'this' ? According to the lines above, 'this' is TheMutableBufferClass.
    /* allocate the new object           */
    newBuffer = new ((RexxClass *)this) RexxMutableBuffer(bufferLength,
defaultSize);
    newBuffer->dataLength = string->getLength();
    /* copy the content                  */
    newBuffer->data->copyData(0, string->getStringData(),
string->getLength());

Q2 :
Why do we have bufferLength and dataLength in RexxMutableBuffer ? Those
attributes are already available in the encapsulated RexxBuffer :
data->bufferSize and data->dataLength

Q3 :
RexxBuffer and RexxString have some helpers to create instances from C++ :
new_buffer and new_string
But nothing similar for RexxMutableBuffer. Any reason ?

Q4 :
In programming guide, I see that NewBufferString lets create a
RexxBufferStringObject which is a mutable String object. It's implemented by
a RexxString, not by a RexxMutableBuffer. Any reason ? Is it because
RexxMutableBuffer would need ProtectedObject which is not available from
API, I think ?

Jean-Louis