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[[Category:C++]]
[[Category:libStatGen]]
[[Category:libStatGen general]]
= InputFile / IFILE =
= InputFile / IFILE =
This is our class for file operations. It hides the underlying file structure from the user. That way code can generically open and operate on a file using the exact same interface without having to know if the file is standard, gzip, or bgzf format (for reading from a file - for reading from stdin and writing, the user has to specify which type to open).
This is our class for file operations. It hides the underlying file structure from the user. That way code can generically open and operate on a file using the exact same interface without having to know if the file is standard, gzip, or bgzf format (for reading from a file - for reading from stdin and writing, the user has to specify which type to open).
The IFILE class is made to mimic FILE. THe typical way to use IFILE is to call the set of global methods contained in InputFile.h that take IFILE as a parameter
To use IFILE, add the following include to your file.
<source lang="cpp">
#include "InputFile.h"
</source>
=== Public Class Methods ===
=== Global IFILE Methods ===
See: http://csg.sph.umich.edu//mktrost/doxygen/current/InputFile_8h.html for documentation on the global IFILE methods.
=== InputFile Class Documentation ===
See: http://csg.sph.umich.edu//mktrost/doxygen/current/classInputFile.html
=== BGZF Notes ===
=== BGZF Notes ===
BgzfFileType::setRequireEofBlock(false);
BgzfFileType::setRequireEofBlock(false);
With that call, the empty block is not checked for when opening the file.
With that call, the empty block is not checked for when opening the file.
=== stdin/stdout ===
This class can be used to read/write to stdin/stdout.
To use stdin/stdout, specify the filename as "-" and use the ifileCompression parameter in ifopen to specify the compression type.
NOTE: even when reading from stdin, you MUST specify the file type. It does not read from stdin to determine the compression type like it does for other files.
'''When writing programs that will use stdout and pipes to send input from one program to the next, make sure that all error, debug, or info messages are written to stderr/cerr and not stdout/cout.'''
=== Example ===
<source lang="cpp">
// specify to open stdin for read.
// replace the - with a filename in order to read from a file.
const char* filename = "-";
IFILE myFilePtr = ifopen(filename, "rb", InputFile::BGZF);
if (myFilePtr == NULL)
{
std::cerr << "Failed to open the file\n";
}
else
{
// File was successfully opened.
// Read the magic string.
char magic[4];
if(ifread(myFilePtr, magic, 4) != 4)
{
std::cerr << "Could not read 4 bytes from the file\n";
}
ifclose(myFilePtr);
myFilePtr = NULL;
}
</source>
