Matrix1Array - how do you expand an array?

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Grismald

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Posted: 29th Jul 2006 09:57

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I want to do something like that:

+ Code Snippet

global dim arr() as integer
array_add_to_bottom(get array ptr(arr()))

FUNCTION array_add_to_bottom(ArrPtr as dword)
   
   local dim temp() as integer
   link array to pointer temp(),ArrPtr
   ARRAY INSERT AT BOTTOM temp()
   unlink array pointer temp()

ENDFUNCTION

I know this code doesn't work, but is there some way to
achieve this?
thanks in advance

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IanM

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Posted: 29th Jul 2006 23:13

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Yes, you have to unlink from the original array first, pass back the new pointer you get from expanding the array, and then relink back to the original array.

+ Code Snippet

global dim arr(1) as integer

print array count(arr())

ptr = get array ptr(arr())            ` Get the array pointer
unlink array pointer arr()            ` Unlink from the original
ptr = array_add_to_bottom(ptr)        ` Call the function
link array to pointer arr(), ptr      ` Link the pointer back to the original array

print array count(arr())
wait key
end

FUNCTION array_add_to_bottom(ArrPtr as dword)

   local dim temp() as integer
   link array to pointer temp(),ArrPtr
   ARRAY INSERT AT BOTTOM temp()
   ArrPtr = get array ptr(temp())     ` Get the new array pointer
   unlink array pointer temp()

ENDFUNCTION ArrPtr                    ` Pass back the new array pointer

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Grismald

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Joined: 4th Mar 2003

Location: France

Posted: 4th Aug 2006 20:42 Edited at: 4th Aug 2006 21:23

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thanks, but actually i would like to have all the code into one function, like this:

+ Code Snippet

global dim arr(1) as integer
ptr = get array ptr(arr())
array_add_to_bottom(ptr)


FUNCTION array_add_to_bottom(ArrPtr as dword)

   local dim temp() as integer
   unlink arrayptr ArrPtr
   link array to pointer temp(),ArrPtr
   ARRAY INSERT AT BOTTOM temp()
   TmpPtr = get array ptr(temp())
   unlink array pointer temp()
   link arrayptr ArrPtr,TmpPtr    

ENDFUNCTION ArrPtr

This means i'd need 2 new functions ,unlink arrayptr and
link arrayptr which would accept an array pointer as argument instead of the array name.
BTW, in the dll readme, you mention a UNLINK ARRAYPTR function

Quote: "UNLINK ARRAYPTR - Unlinks an array from its pointer
UNLINK ARRAYPTR a()"

but it doesn't seem to exist.

EDIT: The goal is to create a function similar to ARRAY INSERT AT BOTTOM which would accept an array pointer instead of an array name.

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IanM

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Posted: 5th Aug 2006 13:20

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It's not technically possible within DBPro code, and here's why - Increasing the size of an array causes DBPro to allocate new memory to build the array into, the data to be moved across, and then the old memory freed. The problem is that the original array variable will still point to the freed memory. That will cause future array or string allocations to be corrupted if you use that array, the memory heap to be corrupted, and even crashes to occur.

It might be possible to do within the plugin, but I'm not sure of that and I'd have to think about it for a while.

UNLINK ARRAYPTR = UNLINK ARRAY POINTER
... it's just a typo.

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DLL Talk / Matrix1Array - how do you expand an array?