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From: Martin Krischik <krischik@users.sourceforge.net>
Newsgroups: comp.lang.ada
Subject: Re: variable lenght strings
Date: Tue, 26 Oct 2004 20:13:56 +0200
Organization: AdaCL
Message-ID: <1845042.MQgRItqYm2@linux1.krischik.com>
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Date: 2004-10-26T20:13:56+02:00
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Pascal Obry wrote:

> 
> Martin Krischik <krischik@users.sourceforge.net> writes:
> 
>> function�Get_Line�(
>> File�:�in�IO.File_Type)
>> return
>> String
>> is
>> Buffer�:�String�(1�..�BufferSize);
>> Last���:�Natural;
>> begin
>> IO.Get_Line�(
>> File�=>�File,
>> Item�=>�Buffer,
>> Last�=>�Last);
>> 
>> if�Last�<�Buffer'Last�then
>> return�Buffer�(1�..�Last);
>> elsif�IO.End_Of_File�(File)�then
>> return�Buffer;
>> else
>> return�Buffer�&�Get_Line�(File);
>            ^^^^^^^^^^^^^^^^^^^^^^^^^^
>          
> This kind of recursivity is very dangerous and could cause a stack
> overflow. It is better to use a non recursive version and to store the
> result into an Unbounded_String for example.

In fact I have got an non recursive version returning an Unbounded_String 
as well:

���function�Get_Line�(
������File�:�in�IO.File_Type)
���return
������S_U.Unbounded_String
���is

������Retval�:�S_U.Unbounded_String�:=�S_U.Null_Unbounded_String;
������Item���:�String�(1�..�BufferSize);
������Last���:�Natural;
���begin
������GetWholeLine�:
������loop
���������IO.Get_Line�(
������������File�=>�File,
������������Item�=>�Item,
������������Last�=>�Last);

���������S_U.Append�(
������������Source���=>�Retval,
������������New_Item�=>�Item�(1�..�Last));

���������exit�GetWholeLine�when�Last�<�Item'Last
����������������������or���IO.End_Of_File�(File);

������end�loop�GetWholeLine;

������return�Retval;
���end�Get_Line;

With Regards

Martin

-- 
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