String Length and Array Indexes in macros

Eike Rathke erack at redhat.com
Tue May 15 20:27:29 UTC 2018


Hi Andrew,

On Tuesday, 2018-05-15 13:43:15 +0000, Andrew Pitonyak wrote:

> Last time I documented Strings and arrays, an array index was limited to
> +/-32K and a string was similarly limited.
> 
> I am now documenting them again and I am hoping that someone knows off hand
> what the new limitations are so that I do not need to scour the code to find
> out. My best guess is that this now uses a 32-bit long, so, +/- 2G.

While internally an SbxArray can handle uint32 indices, there still are
the same limitations. For example DimArray() is limited to uint16
dimensions. The Array() function could digest uint16 (=64K) elements,
but storage index still uses a short int16. Most code has been
untouched, there still may be some other places that access things
through a short (int16) which limits the reliable size to 32K elements.

For strings OUString is used, which theoretically can hold int32 (=2G)
UTF-16 code points during runtime, so that's probably the most
interesting change (well, at least compared to 6 years ago or so).

BUT, probably for some (stream?) compatibility (or oversight?), for
example the TypeLen() function still returns an int16 value because the
result is stored as an int16 (while seeing that, I think it could be
fixed). Also, for persistent storage UTF-16 may have to be converted to
a different encoding, which may halve or third the theoretical capacity
depending on the actual characters used.

Hope that helps

  Eike

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