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b
Guest
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 Posted: Wed Jul 30, 2003 5:46 pm Post subject: Stream troubles |
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i save a ownership file in this way:
from ->position = 0 to ->position = 20 there is a word, then from 21 to 24 a
number.
now using this code i want get the word inside the first 20 sectors of the
file and save it inside a AnsiString, then get the number and save it inside
a int var. For example this is the code i want use to get the number:
void __fastcall TForm1::OpenProjectClick(TObject *Sender)
{
if(OpenDialog1->Execute() == mrOk)
{
Label1->Caption = EncodeNumber(OpenDialog1->FileName);
}
}
//--------------------------------------------------------------------------
-
AnsiString __fastcall TForm1::EncodeNumber(AnsiString ProjectOpenPath)
{
std::auto_ptr<TFileStream> EncStream(new TFileStream(ProjectOpenPath,
fmOpenRead));
EncStream->Position = 20;
TMemoryStream* NumberStream = new TMemoryStream();
NumberStream->Position = 0;
EncStream->Read(NumberStream, 24);
std::auto_ptr<AnsiString> giveNumber(new AnsiString);
giveNumber = NumberStream;
return giveNumber;
}
//--------------------------------------------------------------------------
-
[C++ Error] Program.cpp(931): E2285 Could not find a match for
'auto_ptr<AnsiString>::operator = <_Tp1>(TMemoryStream *)'
[C++ Error] Program.cpp(932): E2285 Could not find a match for
'AnsiString::operator =(auto_ptr<AnsiString>)'
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b
Guest
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Remy Lebeau (TeamB)
Guest
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| Posted: Wed Jul 30, 2003 8:06 pm Post subject: Re: Stream troubles |
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"b" <borland.public.cppbuilder.vcl.components.using> wrote
| Quote: | AnsiString __fastcall TForm1::EncodeNumber(AnsiString ProjectOpenPath)
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That code is not doing what you think it should be doing. See below.
| Quote: | EncStream->Read(NumberStream, 24);
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You are telling the file to read 24 bytes into the memory stream, not to
read the file to position 24.
| Quote: | std::auto_ptr<AnsiString> giveNumber(new AnsiString);
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There is no need to dynamically alocate an AnsiString in this situation.
| Quote: | giveNumber = NumberStream;
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You are trying to assign a TMemoryStream* to an auto_ptr that already
contains an AnsiString*.
| Quote: | return giveNumber;
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You are trying to return an auto_ptr as an AnsiString.
If all you are trying to do is retreive the number from the file, then your
current code is very overkill let alone non-functional anyway. Just do the
following instead:
AnsiString __fastcall TForm1::EncodeNumber(AnsiString ProjectOpenPath)
{
int i = 0;
std::auto_ptr<TFileStream> EncStream(new
TFileStream(ProjectOpenPath, fmOpenRead));
EncStream->Position = 21;
EncStream->ReadBuffer(&i, 4);
return i;
}
Gambit
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Remy Lebeau (TeamB)
Guest
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| Posted: Wed Jul 30, 2003 8:07 pm Post subject: Re: Stream troubles |
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"Liz Albin" <lizalbin (AT) yahooNotThis (DOT) com> wrote
| Quote: | have you tried: EncStream->get()
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That should be '.', not '->':
EncStream.get()
Not that it means anything though since the code was trying to assign an
TMemoryStream to an auto_ptr that already contained an AnsiString, which is
wrong.
Gambit
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Remy Lebeau (TeamB)
Guest
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| Posted: Wed Jul 30, 2003 8:10 pm Post subject: Re: Stream troubles |
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"b" <borland.public.cppbuilder.vcl.components.using> wrote
That has nothing to do with the VCL at all. That is for a completely
different third-party library called FCL (Free Component Library) that is
for the FreePascal compiler. The library is written to have similar
syntaxes as the VCL, but do not confuse it as being the VCL, because it is
not at all.
Gambit
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b
Guest
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| Posted: Wed Jul 30, 2003 10:51 pm Post subject: Re: Stream troubles |
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well, i can run the program, but when i try to Open and read with your
method i get the follow number 8912928 at the place of a simple 2.
Why?
Futhermore if i want read a string of characters for example from the
position 25 at 42, and save it in AnsiString how can i do?
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Remy Lebeau (TeamB)
Guest
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| Posted: Wed Jul 30, 2003 11:14 pm Post subject: Re: Stream troubles |
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"b" <borland.public.cppbuilder.vcl.components.using> wrote
| Quote: | well, i can run the program, but when i try to Open and
read with your method i get the follow number 8912928
at the place of a simple 2.
Why?
|
Please show your actual file data. What exactly does it look like, and what
exactly are you trying to read from it?
| Quote: | Futhermore if i want read a string of characters for
example from the position 25 at 42, and save it in
AnsiString how can i do?
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You have two options:
1) declare an AnsiString, call its SetLength() method, and then pass its
c_str() pointer to the stream's Read() method.
1) Use a TStringStream instead, read the file data into the stream, then you
can access the DataString property after the read.
Gambit
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