I am trying to develop a means of arranging database records in a manner that
permits records that come closest to a specified string to be shown first. I
note that the built in string comparison functions are not explicit with regard
to how they establish the magnitude of the positive or negative number that
they return. When I attempt the following, the result with DmQuickSort is an
error message in terms of trying to access memory in a manner that is not
allowed. I began by defining the function using the commented out text, which
did work well. I want to be able to search using something like "T245a19" and
find "T244a19" at least in proximity to the record that comes out on top, if,
say, there is a "T245a20" in addition. The biggest piece that seems to be
missing now is getting around this memory access problem and assigning the
right magnitude value to "result".
Int16 ClosestCompare(void *r1, void*r2, Int16 unusedInt16, SortRecordInfoPtr
unused1, SortRecordInfoPtr unused2, MemHandle appInfoH)
{
#pragma unused(unusedInt16, unused1, unused2, appInfoH)
Int16 result;
TransStructPtr rec1=(TransStructPtr)r1;
TransStructPtr rec2=(TransStructPtr)r2;
if(rec1->DegreeMatch > rec2->DegreeMatch)
{
int result = 1;
}
if(rec1->DegreeMatch < rec2->DegreeMatch)
{
int result = -1;
}
if(rec1->DegreeMatch = rec2->DegreeMatch)
{
result = 0;
}
/*
//commented out text
Char* TextRec1 = (Char*) MemPtrNew(maxStrIToALen);
Char* TextRec2 = (Char*) MemPtrNew(maxStrIToALen);
StrIToA(TextRec1,rec1->DegreeMatch);
StrIToA(TextRec2,rec2->DegreeMatch);
result=StrCompare(TextRec2,TextRec1);
//commented out text
*/
return result;
}
I am calling and sending the record in the zeroth position to the screen using
the following, which worked with the commented out code:
err = DmQuickSort(gTransformer,ClosestCompare, 0);
Tindex=0;
if(Tindex>=0)
{
myRecord = DmQueryRecord(gTransformer, Tindex);
if (!myRecord)
err = DmGetLastErr();
else
{
rec = (TransStruct*) MemHandleLock(myRecord);
MemHandleUnlock(myRecord);
}
if (err==0)
err = TransformerFormFill(rec);
}
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