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From: Matthew Heaney <matthew_heaney@acm.org>
Subject: Re: Unbounded array
Date: 1999/04/29
Message-ID: <m3g15krlw5.fsf@mheaney.ni.net>#1/1
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References: <37247AA2.116F5E00@wbkst21.mach.uni-karlsruhe.de>
 <7g23a9$k3k$1@nnrp1.dejanews.com>
 <37262C39.D4F16DD8@wbkst21.mach.uni-karlsruhe.de>
NNTP-Posting-Date: Wed, 28 Apr 1999 23:12:27 PDT
Newsgroups: comp.lang.ada
Date: 1999-04-29T00:00:00+00:00
List-Id: <comp.lang.ada>

Pawel Kobylarz <kobylarz@wbkst21.mach.uni-karlsruhe.de> writes:

> Realloc function takes two parameters, the actual pointer and new
> size, and it preserves the data already present in the memory block.
> Realloc is more efficient than allocate-copy-deallocate, because it
> can add a piece of memory without moving existing data if there is
> place after the existing block.

But that isn't guaranteed.  You save the cost of a copy only if there's
an adjacent block large enough to contain the new part of the array.


> In my textbook, I found only operators new and unchecked deallocation,
> nothing similar to realloc(). Is there in ADA something like
> realloc?

No, it is not built in.  However, you could

1) write a binding the C function

2) write your own storage pool that supports a realloc-style operation,
   and bind your access type to that pool; see RM95 13.11

There are open-source implementations of malloc, etc, so you should be
able to use the algorithm to implement an Ada95 version.