> On Apr 4, 2017, at 11:50 PM, Jürgen Hestermann
> wrote:
>
> I am trying to show the memory allocation for the 10x10 array as a "graphic":
>
> arr --> arr[0],arr[1],arr[2],arr[3],arr[4],arr[5],arr[6],arr[7],arr[8],arr[9]
> | | | | | | | | | |
>
> On Apr 4, 2017, at 10:10 PM, Sven Barth via fpc-pascal
> wrote:
>
> While your statement regarding allocation might be true you must not
> forget that a dynamic array consists of a meta data block (length,
> reference count) that is located directly in front of the data block. So
> even if th
Am 2017-04-04 um 16:54 schrieb Ryan Joseph:
>> var arr : array of array of Integer;
>> begin
>> SetLength(arr, 10, 10);
> “then the first array stores a pointer to each sub array.”
> Could you illustrate this is code?
> I don’t think I’m understanding this exactly like it’s represented in memory.
On 04.04.2017 16:27, Ryan Joseph wrote:
>>> Does SetLength on a single level dynamic array not even allocate a
>>> continuous block of memory?
>>
>> Yes, it does (as explained in all the other mails).
>> A (dynamic) array of integer will be allocated as a single block by
>> SetLength.
>> So if yo
On 04.04.2017 16:27, Ryan Joseph wrote:
>>> Does SetLength on a single level dynamic array not even allocate a
>>> continuous block of memory?
>>
>> Yes, it does (as explained in all the other mails).
>> A (dynamic) array of integer will be allocated as a single block by
>> SetLength.
>> So if yo
On Tue, 4 Apr 2017 16:46:02 +0200
Sven Barth via fpc-pascal wrote:
>[...]
> SetLength() allocates a single block of memory,
To avoid misunderstanding: SetLength(a,dim1,dim2) allocates one block
for the dim1 array and then for each element another block.
Mattias
_
> On Apr 4, 2017, at 10:07 PM, Jürgen Hestermann
> wrote:
>
> Am 2017-04-04 um 15:40 schrieb Ryan Joseph:
> > I’m glad I asked because of arrays of pointers is bad news for performance.
>
> I don't think that you will notice a performance issue with dynamic arrays
> (though it highly depends
On 04.04.2017 16:54, Ryan Joseph wrote:
>
>> On Apr 4, 2017, at 9:46 PM, Sven Barth via fpc-pascal
>> wrote:
>>
>> SetLength() allocates a single block of memory, cause array access is
>> ordinary pointer arithmetic. However if you have an array of array then
>> the first array stores a pointer
On 04.04.2017 15:40, Ryan Joseph wrote:
>
>> On Apr 4, 2017, at 7:17 PM, Sven Barth via fpc-pascal
>> wrote:
>>
>> If you want continuous memory areas you need to use static arrays or develop
>> your own dynamic data structure that uses array properties.
>>
>>
>
> I’m glad I asked because of a
> On Apr 4, 2017, at 9:46 PM, Sven Barth via fpc-pascal
> wrote:
>
> SetLength() allocates a single block of memory, cause array access is
> ordinary pointer arithmetic. However if you have an array of array then
> the first array stores a pointer to each sub array.
>
> E.g. the following woul
On 04.04.2017 15:40, Ryan Joseph wrote:
>
>> On Apr 4, 2017, at 7:17 PM, Sven Barth via fpc-pascal
>> wrote:
>>
>> If you want continuous memory areas you need to use static arrays or develop
>> your own dynamic data structure that uses array properties.
>>
>>
>
> I’m glad I asked because of a
Am 2017-04-04 um 15:40 schrieb Ryan Joseph:
> I’m glad I asked because of arrays of pointers is bad news for performance.
I don't think that you will notice a performance issue with dynamic arrays
(though it highly depends on the sizes and levels you use...)
> Does SetLength on a single level d
> On Apr 4, 2017, at 7:17 PM, Sven Barth via fpc-pascal
> wrote:
>
> If you want continuous memory areas you need to use static arrays or develop
> your own dynamic data structure that uses array properties.
>
>
I’m glad I asked because of arrays of pointers is bad news for performance.
Do
Am 2017-04-04 um 15:18 schrieb Jürgen Hestermann:
> var MyArray : array of array of integer;
>
> you can do:
>
> SetLength(MyArray,3);
> SetLength(MyArray[0],2);
> SetLength(MyArray[1],3);
> SetLength(MyArray[2],4);
>
> So MyArray[0] points to an array of 2 integers,
> MyArray[1] points to an arra
Am 2017-04-04 um 13:55 schrieb Ryan Joseph:
> Doesn’t iterating the array default the purpose of FillChar?
> The goal was the most efficient way clear the array with zero’s.
> Even if the array if nested 3 levels deep (anArray[x][y][z])
> it should (I hope) be a contiguous block of memory that was
Am 04.04.2017 13:55 schrieb "Ryan Joseph" :
>
>
> > On Apr 4, 2017, at 4:58 PM, Howard Page-Clark via fpc-pascal <
fpc-pascal@lists.freepascal.org> wrote:
> >
> > You can always use FillChar and its kin on specific 'nested' arrays
like this
> >
> > type
> > TIntArray = array of Integer;
> > TIntI
> On Apr 4, 2017, at 4:58 PM, Howard Page-Clark via fpc-pascal
> wrote:
>
> You can always use FillChar and its kin on specific 'nested' arrays like this
>
> type
> TIntArray = array of Integer;
> TIntIntArray = array of TIntArray;
> TIntIntIntArray = array of TIntIntArray;
>
> procedure
Am 04.04.2017 12:52 schrieb "Mark Morgan Lloyd" <
markmll.fpc-pas...@telemetry.co.uk>:
>
> On 02/04/17 10:00, Jonas Maebe wrote:
>
>> Allocating new memory via setlength also clears the memory (+ the
>> overhead of allocating the memory).
>
>
> Jonas, is it still the case that if SetLength() result
Am 2017-04-04 um 12:51 schrieb Mark Morgan Lloyd:
> On 02/04/17 10:00, Jonas Maebe wrote:
>> Allocating new memory via setlength also clears the memory (+ the
>> overhead of allocating the memory).
> Jonas, is it still the case that if SetLength() results in existing data
being moved that the ori
On 02/04/17 10:00, Jonas Maebe wrote:
Allocating new memory via setlength also clears the memory (+ the
overhead of allocating the memory).
Jonas, is it still the case that if SetLength() results in existing data
being moved that the original- which might be e.g. an unencrypted
password- isn
On 04/04/17 05:25, Ryan Joseph wrote:
Is it possible use FillChar on a multidimensional arrays?
arr: array of array of array of integer.
SetLength(arr, 3, 3, 3);
FillChar(arr[0], (3*3*3)*sizeof(integer), false);
I’m just getting crashes.
You can always use FillChar and its kin on specific 'ne
Am 04.04.2017 05:25 schrieb "Ryan Joseph" :
>
> Thanks for the tips, I appreciate it.
>
> This is all pretty trivial but it’s kind of annoying that using an inline
class function is more efficient than a constructor despite having
identical functionality. It's tempting to remove the constructors no
Am 04.04.2017 06:55 schrieb "Ryan Joseph" :
>
>
> > On Apr 2, 2017, at 11:02 PM, Sven Barth via fpc-pascal <
fpc-pascal@lists.freepascal.org> wrote:
> >
> > can be easily seen by looking at the implementation of SetLength() in
> > $fpcdir/rtl/inc/dynarr.inc, fpc_dynarray_setlength().
> > Especially
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