Testing for EOF in file with binary data

[David Warner]

Greetings!

I am working on a C app that needs to read print files generated by lp
that contain HP LaserJet PCL codes. If the PCL contains binary data to
define a bit map to be printed on the page, either icon or soft-font
download, the EOF test ends prematurely and does not read the entire
file. How do I get around testing for EOF and not detect the EOF value
within the file? Am I missing something?

More Data:

If the print file just contains text data or does not have a bit map
value, the print file is read correctly.

Suggestions?

Thanks in advance!

David Warner
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[Vladimir Oka]

David Warner wrote:

Greetings!

I am working on a C app that needs to read print files generated by lp
that contain HP LaserJet PCL codes. If the PCL contains binary data to
define a bit map to be printed on the page, either icon or soft-font
download, the EOF test ends prematurely and does not read the entire
file. How do I get around testing for EOF and not detect the EOF value
within the file? Am I missing something?

More Data:

If the print file just contains text data or does not have a bit map
value, the print file is read correctly.

Suggestions?

With no code I can only guess that you're opening the file in text
mode. Have you tried opening it in binary mode?

Also, if you're problem is in C, why posto to all the C++ groups as
well?

[Google made me remove alt.comp.lang.l earn-c-c++ from the list.]
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[Kenneth Brody]

David Warner wrote:

Greetings!

I am working on a C app that needs to read print files generated by lp
that contain HP LaserJet PCL codes. If the PCL contains binary data to
define a bit map to be printed on the page, either icon or soft-font
download, the EOF test ends prematurely and does not read the entire
file. How do I get around testing for EOF and not detect the EOF value
within the file? Am I missing something?

[...]

By definition, EOF cannot be in the file.

1) Have you opened the file in binary mode? (On some platforms, if you
open a binary file in text mode, the C runtime library may think
that you've hit EOF befire you really do.)

2) How are you checking for EOF? (Remember, fgetc returns an int, not
a char.)

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[Joe Wright]

David Warner wrote:

Greetings!

I am working on a C app that needs to read print files generated by lp
that contain HP LaserJet PCL codes. If the PCL contains binary data to
define a bit map to be printed on the page, either icon or soft-font
download, the EOF test ends prematurely and does not read the entire
file. How do I get around testing for EOF and not detect the EOF value
within the file? Am I missing something?

More Data:

If the print file just contains text data or does not have a bit map
value, the print file is read correctly.

Suggestions?

Thanks in advance!

David Warner

The EOF character is an anachronism, an artifact older simpler file
systems like CP/M. The EOF character had a value 0x1a (26) or ^Z.

The EOF character is not needed these days. You can stop C from checking
for it by opening your files in "rb" mode instead of "r" or "rt" mode.
You will still get the EOF indicator at the end of file but you will not
get it simply because you read a character 00011010.

--
Joe Wright
"Everything should be made as simple as possible, but not simpler."
--- Albert Einstein ---
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[Brian Inglis]

On 11 May 2006 05:15:55 GMT in comp.lang.c.mod erated, David Warner
<da******@westb ase.com> wrote:

Greetings!

I am working on a C app that needs to read print files generated by lp
that contain HP LaserJet PCL codes. If the PCL contains binary data to
define a bit map to be printed on the page, either icon or soft-font
download, the EOF test ends prematurely and does not read the entire
file. How do I get around testing for EOF and not detect the EOF value
within the file? Am I missing something?

More Data:

If the print file just contains text data or does not have a bit map
value, the print file is read correctly.

Suggestions?

Open input file with binary data in binary read mode?

#include <stdio.h>
#include <stdlib.h>

char name[FILENAME_MAX+1];
FILE *fp;
....
if (!(fp = fopen( name, "rb")))
{
perror( name );
exit(1);
}

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Thanks. Take care, Brian Inglis Calgary, Alberta, Canada

Br**********@CS i.com (Brian[dot]Inglis{at}Syste maticSW[dot]ab[dot]ca)
fake address use address above to reply
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[pete]

Joe Wright wrote:

The EOF character

There is no EOF character.

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[jjf]

David Warner wrote:

Greetings!

I am working on a C app that needs to read print files generated by lp
that contain HP LaserJet PCL codes. If the PCL contains binary data to
define a bit map to be printed on the page, either icon or soft-font
download, the EOF test ends prematurely and does not read the entire
file. How do I get around testing for EOF and not detect the EOF value
within the file? Am I missing something?

More Data:

If the print file just contains text data or does not have a bit map
value, the print file is read correctly.

Suggestions?

What was wrong with the answers you got when you posted a similar
question to comp.lang.c on April 27?
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[Richard Heathfield]

Joe Wright said:

The EOF character is not needed these days. You can stop C from checking
for it by opening your files in "rb" mode instead of "r" or "rt" mode.

The fopen function has no "rt" mode. Opening a file in "rt" mode invokes
undefined behaviour.

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email: rjh at above domain (but drop the www, obviously)
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[Keith Thompson]

jj*@bcs.org.uk writes:

David Warner wrote:

I am working on a C app that needs to read print files generated by lp
that contain HP LaserJet PCL codes. If the PCL contains binary data to
define a bit map to be printed on the page, either icon or soft-font
download, the EOF test ends prematurely and does not read the entire
file. How do I get around testing for EOF and not detect the EOF value
within the file? Am I missing something?

[snip] What was wrong with the answers you got when you posted a similar
question to comp.lang.c on April 27?

He cross-posted (simultaneously ) to comp.lang.c and
comp.lang.c.mod erated. Articles posted to comp.lang.c appear on
servers as soon as they're propagated. Articles posted to
comp.lang.c.mod erated appear when the moderator gets around to
approving and posting them. (He also cross-posted to comp.lang.c++,
which is almost always a bad idea.)

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[jjf]

Keith Thompson wrote:

jj*@bcs.org.uk writes:

David Warner wrote:

I am working on a C app that needs to read print files generated by lp
that contain HP LaserJet PCL codes. If the PCL contains binary data to
define a bit map to be printed on the page, either icon or soft-font
download, the EOF test ends prematurely and does not read the entire
file. How do I get around testing for EOF and not detect the EOF value
within the file? Am I missing something?

[snip]

What was wrong with the answers you got when you posted a similar
question to comp.lang.c on April 27?

He cross-posted (simultaneously ) to comp.lang.c and
comp.lang.c.mod erated. Articles posted to comp.lang.c appear on
servers as soon as they're propagated. Articles posted to
comp.lang.c.mod erated appear when the moderator gets around to
approving and posting them. (He also cross-posted to comp.lang.c++,
which is almost always a bad idea.)

He did that (and also cross-posted it to alt.comp.lang.l earn-c-c++) for
the message which started this thread. That was sent in the early hours
of May 11 (or perhaps forwarded by the moderator at that time, though
since the replies didn't happen until May 22 I had guessed that May
10/11 was the date of original posting). I was referring to message
<da************ *************** *@sn-ip.vsrv-sjc.supernews.n et> which was
sent just to comp.lang.c on April 27, and got immediate answers. I may
be misinterpreting something, but I can't see what.
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[Flash Gordon]

David Warner wrote:

Greetings!

I am working on a C app that needs to read print files generated by lp
If you are writing in C then you should not post to comp.lang.c++, C++
is a different language. If you are programming in C++ you should not
have posted to comp.lang.c. Cross-posting to both is rarely the correct
thing to do.
that contain HP LaserJet PCL codes. If the PCL contains binary data to
define a bit map to be printed on the page, either icon or soft-font
download, the EOF test ends prematurely and does not read the entire
file. How do I get around testing for EOF and not detect the EOF value
within the file? Am I missing something?

<snip>

Open the file in binary mode rather than text mode.
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