1-dimensional arrays with arbitrary bounds
Posted: Wed Sep 25, 2013 8:38 pm
Normally, arrays in PB always have a lower bound = 0, and an upper bound >= 0. But if we want to use an array with say 2000 to 2005 as indexes (this could e.g. mean years), it's not a good idea to create an array with indexes from 0 to 2005, where the elements from 0 to 1999 will never be used, and so do nothing but waste space in memory.
The following pretty simple but rather useful code allows to create and use arrays with arbitrary bounds (they can even be negative). It is only for 1-dimensional arrays, because this allows to keep the code simple, and I personally rarely need arrays with more dimensions. Putting this code into a module doesn't yield a big advantage. But the reason why I did do so is, that this code can be used by other modules only if it is inside a module itself.
Have fun!
The following pretty simple but rather useful code allows to create and use arrays with arbitrary bounds (they can even be negative). It is only for 1-dimensional arrays, because this allows to keep the code simple, and I personally rarely need arrays with more dimensions. Putting this code into a module doesn't yield a big advantage. But the reason why I did do so is, that this code can be used by other modules only if it is inside a module itself.
Have fun!
Code: Select all
; PB 5.20 LTS
DeclareModule FlexBounds
Structure ArrayB
LBound.i
Array Value.b(0)
EndStructure
Structure ArrayA
LBound.i
Array Value.a(0)
EndStructure
Structure ArrayC
LBound.i
Array Value.c(0)
EndStructure
Structure ArrayW
LBound.i
Array Value.w(0)
EndStructure
Structure ArrayU
LBound.i
Array Value.u(0)
EndStructure
Structure ArrayL
LBound.i
Array Value.l(0)
EndStructure
Structure ArrayI
LBound.i
Array Value.i(0)
EndStructure
Structure ArrayQ
LBound.i
Array Value.q(0)
EndStructure
Structure ArrayF
LBound.i
Array Value.f(0)
EndStructure
Structure ArrayD
LBound.i
Array Value.d(0)
EndStructure
Structure ArrayS
LBound.i
Array Value.s(0)
EndStructure
Macro ArrayDim (_Array_, _LBound_, _UBound_)
If _LBound_ <= _UBound_
_Array_\LBound = _LBound_
Dim _Array_\Value(_UBound_-_LBound_)
Else
MessageRequester("Error", "Macro 'FlexBounds::ArrayDim': _LBound_ > _UBound_")
End
EndIf
EndMacro
Macro ArrayVal (_Array_, _Index_)
_Array_\Value(_Index_-_Array_\LBound)
EndMacro
EndDeclareModule
Module FlexBounds
EndModule
CompilerIf #PB_Compiler_IsMainFile
; -- Module demo
EnableExplicit
Define last.i, i.i
Define trips.FlexBounds::ArrayS, year.i
FlexBounds::ArrayDim(trips, 2000, 2004)
FlexBounds::ArrayVal(trips, 2000) = "Italy"
FlexBounds::ArrayVal(trips, 2001) = "USA"
FlexBounds::ArrayVal(trips, 2002) = "Norway"
FlexBounds::ArrayVal(trips, 2003) = "Australia"
FlexBounds::ArrayVal(trips, 2004) = "my balcony"
For year = 2000 To 2004
Debug Str(year) + ": " + FlexBounds::ArrayVal(trips, year)
Next
Debug "-- True indexes:"
last = ArraySize(trips\Value())
For i = 0 To last
Debug Str(i) + ": " + trips\Value(i)
Next
Debug "==================="
Define demo.FlexBounds::ArrayQ, LBound.i, UBound.i, count.i
; Even negative indexes are possible:
LBound = -3
UBound = 2
FlexBounds::ArrayDim(demo, LBound, UBound)
For i = LBound To UBound
FlexBounds::ArrayVal(demo, i) = count
count + 1
Next
For i = LBound To UBound
Debug RSet(Str(i), 2) + ": " + FlexBounds::ArrayVal(demo, i)
Next
Debug "-- True indexes:"
last = ArraySize(demo\Value())
For i = 0 To last
Debug Str(i) + ": " + demo\Value(i)
Next
CompilerEndIf
