[Mesa-dev] [PATCH v2 27/64] gallium/util: add new util_dynarray_{shrink, delete} helpers

[Samuel Pitoiset]

On 06/08/2017 07:39 PM, Marek Olšák wrote:
> On Thu, Jun 8, 2017 at 12:26 PM, Samuel Pitoiset
> <samuel.pitoiset at gmail.com> wrote:
>>
>>
>> On 06/07/2017 06:21 PM, Nicolai Hähnle wrote:
>>>
>>> On 30.05.2017 22:35, Samuel Pitoiset wrote:
>>>>
>>>> These helpers will be used for handling dynamic arrays of resident
>>>> texture/image handles.
>>>>
>>>> Signed-off-by: Samuel Pitoiset <samuel.pitoiset at gmail.com>
>>>> ---
>>>>    src/gallium/auxiliary/util/u_dynarray.h | 20 ++++++++++++++++++++
>>>>    1 file changed, 20 insertions(+)
>>>>
>>>> diff --git a/src/gallium/auxiliary/util/u_dynarray.h
>>>> b/src/gallium/auxiliary/util/u_dynarray.h
>>>> index 7b7a093d82..d6f3d5c901 100644
>>>> --- a/src/gallium/auxiliary/util/u_dynarray.h
>>>> +++ b/src/gallium/auxiliary/util/u_dynarray.h
>>>> @@ -109,6 +109,26 @@ util_dynarray_trim(struct util_dynarray *buf)
>>>>    #define util_dynarray_element(buf, type, idx) ((type*)(buf)->data +
>>>> (idx))
>>>>    #define util_dynarray_begin(buf) ((buf)->data)
>>>>    #define util_dynarray_end(buf) ((void*)util_dynarray_element((buf),
>>>> char, (buf)->size))
>>>> +#define util_dynarray_shrink(buf, type, begin, end)
>>>> \
>>>> +   do {
>>>> \
>>>> +      void *__begin = util_dynarray_element((buf), type, (begin));
>>>> \
>>>> +      void *__end = util_dynarray_element((buf), type, (end));
>>>> \
>>>> +      if ((end) * sizeof(type) < (buf)->size)
>>>> \
>>>> +         memmove(__begin, __end, (buf)->size - ((end) * sizeof(type)));
>>>> \
>>>> +      (buf)->size = (buf)->size - ((end) - (begin)) * sizeof(type);
>>>> \
>>>> +   } while (0)
>>>> +#define util_dynarray_delete(buf, type, v)                           \
>>>> +   do {                                                              \
>>>> +      unsigned num_elements = (buf)->size / sizeof(type);            \
>>>> +      unsigned i;                                                    \
>>>> +      for (i = 0; i < num_elements; i++) {                           \
>>>> +         type __v = *util_dynarray_element((buf), type, (i));        \
>>>> +         if (v == __v) {                                             \
>>>> +            util_dynarray_shrink((buf), type, i, i + 1);             \
>>>> +            break;                                                   \
>>>> +         }                                                           \
>>>> +      }                                                              \
>>>> +   } while (0)
>>>
>>>
>>> Does the order of elements matter? If not, it would be better to just copy
>>> the last element into the gap that is left by the deleted element.
>>
>>
>> It doesn't matter, at least not for bindless handles.
>>
>>>
>>> Might be wise to rename the macro to util_dynarray_delete_unordered to
>>> avoid future confusion.
> 
> I think Nicolai meant that the "util_dynarray_delete_unordered" name
> be used for the case when it copies the last element to the gap.

Yes, this is what I did. Copy the last element into the gap, rename to 
util_dynarray_delete_unordered and remove now unused util_dynarray_shrink.

> 
> Marek
>