PureBasic Forums - English

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Procedure AllocateMemoryAligned(size.l)
  Protected diff.l, *ptr.Long = #Null
  If size > ($7FFFFFFF-16) 
    ProcedureReturn #Null
  EndIf 
  *ptr = AllocateMemory(size+16)
  If Not *ptr
    ProcedureReturn *ptr
  EndIf 
  diff = ((-*ptr - 1)&15) + 1
  *ptr = *ptr + diff;
  PokeB(*ptr-1, diff)
  ProcedureReturn *ptr
EndProcedure

Procedure FreememoryAligned(*ptr)
  If *ptr
    FreeMemory(*ptr - PeekB(*ptr-1))
  EndIf 
EndProcedure

Procedure ReAllocateMemoryAligned(*ptr, size.l)
  Protected diff.l
  If size > ($7FFFFFFF-16) 
    ProcedureReturn #Null
  EndIf
  If Not *ptr
    ProcedureReturn AllocateMemoryAligned(size.l)
  EndIf
  diff = PeekB(*ptr-1)
  ProcedureReturn ReAllocateMemory(*ptr-diff, size+diff)+diff
EndProcedure

Procedure zeroAllocateMemoryAligned(size.l)
  Protected *ptr = AllocateMemoryAligned(size)
  Protected *ptr_b.Byte = *ptr
  Protected *ptr_l.Long = *ptr
  Protected *ptr_end = *ptr+size
  If *ptr
    If Not size%4 ; size gots a 32Bit boundary?
      While *ptr_l < *ptr_end
        *ptr_l\l = 0
        *ptr_l+4
      Wend
    Else
      While *ptr_b < *ptr_end
        *ptr_b\b = 0
        *ptr_b+1
      Wend
    EndIf 
    ProcedureReturn *ptr
  EndIf
EndProcedure

test = zeroAllocateMemoryAligned(1024)

Debug test

FreememoryAligned(test)

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EnableExplicit
DisableDebugger
Define k,count,*mem
For k=0 To 1000000
  *mem=AllocateMemory(20+Random(20))
  If *mem%8<>0 ;check if it is not aligned to 64bit boundary
    count+1
  EndIf
  ;FreeMemory(*mem) ;don't free memory!
Next
EnableDebugger
Debug count

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Structure TestAlign
  Blub.b

  ;Blub brackes the alignment as its only 1 byte big

  Align1[3].b

  ;we just insert a byte array with 3 elements to get the 4 byte alignment for the next structure element

  Bla.l
EndStructure

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Structure Test
  A.w
  B.b
  C.b ; <- no alignment needed?
  ..[3].b
  D.l
  ..[4].b ; <- should be aligned for 8 bytes?
  E.q
  F.b
  ..[7].b ; <- should be aligned for 8 bytes?
  G.q
EndStructure