If I simulate what ShiftBuffersUp and ShiftBufferDown do, I think thats wrong First what…
Jeroen van Iddekinge wrote 35 lines
Hi,
If I simulate what ShiftBuffersUp and ShiftBufferDown do, I think
thats wrong
First what shiftbuffersup does:
For example
Buffer: 0123456 (numbers ar original content of buffer before call to shift buffersup )
procedure is called with the following:
Offset=2
Distance=3
Buffercount=7:
FirstMove
move1:
"Move(FBuffers[Offset],Temp^,MoveSize);"
Temp=234 (temp containts the old buffer 2,3 and 4)
buffer=unchanged
move2:
Move(FBuffers[Offset+Distance],FBuffers[Offset],
(FBufferCount-Distance-Offset)*SizeOf(Pchar));
=5 =2 (2)*sizeof()
Temp=unchanged
buffer=01563456
move3:
Move(Temp^,FBuffers[FBufferCount-Distance-Offset],MoveSize);
2 (3)*sizeof
temp=unchanged
buffer=0123456 <==final.
If i look at the result i find it verry strange...
So far as I understand what procedure ShiftBuffersDown does, it rotate all the buffers. Thats compleetly different what ShiftBuffersUp does. For
rotation you don't need an offset parameter, so why does ShiftBuffers have a 'offset' parameter?
The 'offset' is used to make a gap:
[ABCDEFGHIJK]
[ABC DEFGHIJ]
This is needed when doing an insert The insert needs to create a new buffer at the current location (which is the 'offset'). see line 1043:
ShiftBuffers(1,FActiveRecord);But I agree the implementation is messy.
I wanted to have the buffer management in 1 routine; For clarity it may be needed to split it out in 2 routines, where 1 does simple rotation (forward/backward) and the second makes the gap for the new record.
Feel free to have a go at it :-)
Michael.