[Mono-list] Mono 0.23 Bug in the method System.IO.StringReader.Read
Igor Nosyryev
nosyryev@attbi.com
Sat, 19 Apr 2003 19:06:48 -0400
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This is absolutely right. But the error is still here. I just got wrong =
target :-) To fix it we need to change:
. . .
Array.Copy(sourceChars, nextChar, buffer, index, charsToRead );
nextChar +=3D count;
. . .
to
. . .
Array.Copy(sourceChars, nextChar, buffer, index, charsToRead );
nextChar +=3D charsToRead;
. . .
--------------------------
Igor Nosyryev
E-mail: nosyryev@attbi.com
----- Original Message -----=20
From: 2a5gjx302@sneakemail.com=20
To: nosyryev@attbi.com=20
Sent: Saturday, April 19, 2003 5:07 PM
Subject: Re: [Mono-list] Mono 0.23 Bug in the method =
System.IO.StringReader.Read
At 04:11 PM 19/04/2003 -0400, you wrote:=20
>>>>
Class: System.IO.StringReader
Method: public override int Read( char[] buffer, int index, int count =
)
Problem:
If there are no more characters (end-of-stream) call to this method =
generates the exception. But it should just return 0.
CVS code:
public override int Read( char[] buffer, int index, int count ) {
CheckObjectDisposedException ();
if( buffer =3D=3D null ) {
throw new ArgumentNullException();
} else if( buffer.Length - index < count ) {
throw new ArgumentException();
} else if( index < 0 || count < 0 ) {
throw new ArgumentOutOfRangeException();
}
int charsToRead;
if( nextChar + count > sourceLength ) {
charsToRead =3D sourceLength - nextChar;
} else {
charsToRead =3D count;
}
Array.Copy(sourceChars, nextChar, buffer, index, charsToRead );
nextChar +=3D count;
return charsToRead;
}
Make change:
public override int Read( char[] buffer, int index, int count ) {
CheckObjectDisposedException ();
if( buffer =3D=3D null ) {
throw new ArgumentNullException();
} else if( buffer.Length - index < count ) {
throw new ArgumentException();
} else if( index < 0 || count < 0 ) {
throw new ArgumentOutOfRangeException();
}
int charsToRead;
if( nextChar + count > sourceLength ) {
charsToRead =3D sourceLength - nextChar;
} else {
charsToRead =3D count;
}
if(charsToRead < 1) return 0;
Array.Copy(sourceChars, nextChar, buffer, index, charsToRead );
nextChar +=3D count;
return charsToRead;
}
<<<<
Based on the source code, and on where you inserted the check, it =
looks like the exception is occurring as a result of Array.Copy being =
passed a value of 0 as the number of elements to copy. If this is the =
case, then this is what is in error; Array.Copy should accept a value of =
0 for the number of elements to copy.
Jonathan Gilbert
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<META http-equiv=3DContent-Type content=3D"text/html; =
charset=3Diso-8859-1">
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<BODY bgColor=3D#ffffff>
<DIV><FONT face=3DVerdana size=3D2>This is absolutely right. But the =
error is still=20
here. I just got wrong target :-) To fix it we need to =
change:</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2></FONT> </DIV>
<DIV><FONT face=3D"Courier New" size=3D2>. . .</FONT></DIV>
<DIV><FONT face=3D"Courier New" size=3D2>Array.Copy(sourceChars, =
nextChar, buffer,=20
index, charsToRead );<BR><BR>nextChar +=3D count;</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2><FONT face=3D"Courier New">. .=20
.<BR></FONT></DIV></FONT>
<DIV><FONT face=3DVerdana size=3D2>to</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2></FONT> </DIV>
<DIV><FONT face=3D"Courier New" size=3D2>. . .</FONT></DIV>
<DIV><FONT face=3D"Courier New" size=3D2>Array.Copy(sourceChars, =
nextChar, buffer,=20
index, charsToRead );<BR><BR>nextChar +=3D <FONT=20
color=3D#ff0000>charsToRead</FONT>;</FONT></DIV>
<DIV><FONT size=3D2><FONT face=3D"Courier New">. . =
.<BR></FONT></FONT></DIV>
<DIV><FONT size=3D2><FONT=20
face=3D"Courier New">--------------------------</DIV></FONT></FONT>
<DIV><FONT face=3DVerdana size=3D2>Igor Nosyryev</FONT></DIV>
<DIV><FONT face=3DVerdana size=3D2>E-mail: </FONT><A=20
href=3D"mailto:nosyryev@attbi.com"><FONT face=3DVerdana=20
size=3D2>nosyryev@attbi.com</FONT></A></DIV>
<BLOCKQUOTE=20
style=3D"PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; =
BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
<DIV style=3D"FONT: 10pt arial">----- Original Message ----- </DIV>
<DIV=20
style=3D"BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: =
black"><B>From:</B>=20
<A title=3D2a5gjx302@sneakemail.com=20
href=3D"mailto:2a5gjx302@sneakemail.com">2a5gjx302@sneakemail.com</A> =
</DIV>
<DIV style=3D"FONT: 10pt arial"><B>To:</B> <A =
title=3Dnosyryev@attbi.com=20
href=3D"mailto:nosyryev@attbi.com">nosyryev@attbi.com</A> </DIV>
<DIV style=3D"FONT: 10pt arial"><B>Sent:</B> Saturday, April 19, 2003 =
5:07=20
PM</DIV>
<DIV style=3D"FONT: 10pt arial"><B>Subject:</B> Re: [Mono-list] Mono =
0.23 Bug in=20
the method System.IO.StringReader.Read</DIV>
<DIV><BR></DIV>At 04:11 PM 19/04/2003 -0400, you wrote:=20
<BR>>>>><BR><?fontfamily><?param Verdana><?smaller>Class:=20
=
System.IO.StringReader<BR><?/smaller><?/fontfamily><BR><?fontfamily><?par=
am Verdana><?smaller>Method:=20
public override int Read( char[] buffer, int index, int count =
)<BR><?/smaller><?/fontfamily><BR><?fontfamily><?param =
Verdana><?smaller>Problem:<BR>If=20
there are no more characters (end-of-stream) call to this method =
generates the=20
exception. But it should just return =
0.<BR><?/smaller><?/fontfamily><BR><?fontfamily><?param =
Verdana><?smaller>CVS=20
code:<BR><?/smaller><?/fontfamily><BR><?smaller>public override int =
Read(=20
char[] buffer, int index, int count )=20
{<BR><?/smaller><BR>CheckObjectDisposedException ();<BR><BR>if( buffer =
=3D=3D null=20
) {<BR>throw new ArgumentNullException();<BR>} else if( buffer.Length =
- index=20
< count ) {<BR>throw new ArgumentException();<BR>} else if( index =
< 0 ||=20
count < 0 ) {<BR>throw new =
ArgumentOutOfRangeException();<BR>}<BR><BR>int=20
charsToRead;<BR><BR>if( nextChar + count > sourceLength ) =
{<BR>charsToRead=20
=3D sourceLength - nextChar;<BR>} else {<BR>charsToRead =3D=20
count;<BR>}<BR><BR>Array.Copy(sourceChars, nextChar, buffer, index,=20
charsToRead );<BR><BR>nextChar +=3D count;<BR><BR>return=20
charsToRead;<BR>}<BR><BR><?fontfamily><?param Verdana><?smaller>Make=20
change:<BR><?/smaller><?/fontfamily><BR><?smaller>public override int =
Read(=20
char[] buffer, int index, int count )=20
{<BR><?/smaller><BR>CheckObjectDisposedException ();<BR><BR>if( buffer =
=3D=3D null=20
) {<BR>throw new ArgumentNullException();<BR>} else if( buffer.Length =
- index=20
< count ) {<BR>throw new ArgumentException();<BR>} else if( index =
< 0 ||=20
count < 0 ) {<BR>throw new =
ArgumentOutOfRangeException();<BR>}<BR><BR>int=20
charsToRead;<BR><BR>if( nextChar + count > sourceLength ) =
{<BR>charsToRead=20
=3D sourceLength - nextChar;<BR>} else {<BR>charsToRead =3D =
count;<BR>}<BR><?color><?param ffff,0000,0000><?smaller>if(charsToRead =
< 1)=20
return 0;<BR><?/smaller><?/color><BR>Array.Copy(sourceChars, nextChar, =
buffer,=20
index, charsToRead );<BR><BR>nextChar +=3D count;<BR><BR>return=20
charsToRead;<BR>}<BR><<<<<BR><BR>Based on the source code, =
and on=20
where you inserted the check, it looks like the exception is occurring =
as a=20
result of Array.Copy being passed a value of 0 as the number of =
elements to=20
copy. If this is the case, then this is what is in error; Array.Copy =
should=20
accept a value of 0 for the number of elements to =
copy.<BR><BR>Jonathan=20
Gilbert<BR></BLOCKQUOTE></BODY></HTML>
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