dynamic array memory allocation
Oskar Linde
oskar.lindeREM at OVEgmail.com
Wed May 16 09:06:00 PDT 2007
Greg Weber skrev:
>> AFAIK there's no way to shrink the memory allocated to an array, and the
>> closest you can get is to call .dup on a slice. This will get you a copy
>> of part of the array, allowing the original to be garbage collected
>> (assuming no more references to it exist).
>
> So here is my attempt.
>
> bool downsize(T,I)(inout T[] arr, I downSize) {
> static assert(is(I:size_t),"downsize needs an integer size parameter");
>
> if (downSize < arr.length) {
> auto downsized = arr[0 .. downsize].dup;
> arr = downsized;
> return true;
> }
> return false;
> }
>
>
> bool allocate(T,I)(inout T[] arr, I reservedSize) {
> static assert(is(I:size_t),"reserve needs an integer size parameter");
> size_t l = arr.length;
> if (reservedSize > l) {
> arr.length = reservedSize;
> arr.length = l;
> return true;
> }
> return false;
> }
>
Looks good, except possibly the bool return value of allocate, as there
is no guarantee a reallocation really happened even though it returns
true. A better way would perhaps be to compare the .ptr and return true
if it changed.
/Oskar
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