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From: Tero Koskinen <tero.koskinen@iki.fi>
Newsgroups: comp.lang.ada
Subject: Re: Ada.Strings.Fixed.Count raises Storage_Error
Date: Thu, 12 May 2016 18:22:08 +0300
Organization: JSA Research & Innovation
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Xref: news.eternal-september.org comp.lang.ada:30390
Date: 2016-05-12T18:22:08+03:00
List-Id: <comp.lang.ada>

Hi,

12.5.2016, 14.36, Xavier Petit wrote:
> Hello, I would like to know if it is normal or a known bug.
>
> function Count
>    (Source  : String;
>     Pattern : String;
>     Mapping : Maps.Character_Mapping := Maps.Identity) return Natural;
>
> When Source'Last = Positive'Last and Pattern'Length = 1, I get
> Storage_Error, it seems this is because the checks are suppressed in
> this GNAT runtime function ? So with checks it would result a
> Constraint_Error ?
...
>
> Here the code :
>
> with Ada.Strings.Fixed, Ada.Integer_Text_IO;
> use  Ada.Strings.Fixed, Ada.Integer_Text_IO;
>
> procedure Test_Count is
>     S : constant String (Positive'Last - 2 .. Positive'Last) := "Ada";
> begin
>     Put (Count (Source => S,                         Pattern => "AA"));
>     Put (Count (Source => S (S'First .. S'Last - 1), Pattern => "A"));
>     Put (Count (Source => S,                         Pattern => "A"));
> end;
>
> Output on gnat-gcc 5.3.1 :
>
>            0          1
>
> raised STORAGE_ERROR : stack overflow or erroneous memory access

When compiled with Janus/Ada the output is following:
C:\Work\xavier-fixed-count\obj> test_cou
      0     1     1
C:\Work\xavier-fixed-count\obj>

I would say that Janus/Ada is correct here and you have found a bug from 
GNAT.


>
> Thanks by advance
>

Yours,
  Tero