Ticket #215 (Fixed)Tue Jul 21 15:18:28 UTC 2009

TextGadgets claims MORE from RMA when a gadget is removed andothers of the same type remain.

Reported by:	Christopher Bazley (288)	Severity:	Minor
Part:	RISC OS: Module	Release:
Milestone:		Status	Fixed

Details by Christopher Bazley (288):

When a Scrollbar, ScrollList or TextArea gadget is removed, the TextGadgets module makes a hamfisted attempt to shrink the RMA block containing its array of pointers to the internal data structures for that type of gadget. The only exception is when removing the final gadget, when the RMA block is instead freed.

Unfortunately, the RMA block is expanded to a silly size instead of being shrunk, because the wrong type specifier is used with the ‘sizeof’ operator (e.g. ‘PrivateScrollbar’ instead of ‘PrivateScrollbar *’):

// No need to generate an error if the realloc fails, ’cos // it’ll just realloc next time, hopefully new_list = realloc(scrollbar_list, sizeof(PrivateScrollbar) * (j+1));

Tragically this isn’t the only thing wrong with the calculation: The comments saying “j points to last entry” are a lie; j is actually the index of the NULL terminator (i.e. the number of gadgets). Therefore ‘j+1’ should be the current number of array elements, which isn’t appropriate as the new number of array elements.