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/*
* Crossfire -- cooperative multi-player graphical RPG and adventure game
*
* Copyright (c) 1999-2014 Mark Wedel and the Crossfire Development Team
* Copyright (c) 1992 Frank Tore Johansen
*
* Crossfire is free software and comes with ABSOLUTELY NO WARRANTY. You are
* welcome to redistribute it under certain conditions. For details, please
* see COPYING and LICENSE.
*
* The authors can be reached via e-mail at <crossfire@metalforge.org>.
*/
/**
* @file
* Functions for creating text output files. During (re-)writing a new file or
* if a write error occurs the old file contents are still available.
*
* Example usage:
* <code>
* <pre>
* OutputFile of;
* FILE *f;
* f = of_open(&of, "some_file.txt", llevError);
* if (f == NULL)
* return;
* fprintf(f, "...");
* fprintf(f, "...");
* if (!of_close(&of))
* return;
* </pre>
* </code>
*/
#ifndef OUTPUT_FILE_H
#define OUTPUT_FILE_H
#include <stdio.h>
typedef struct
{
/**
* The original output file that is written.
*/
char *fname;
/**
* The temporary output file that is written to until #of_close() is
* called.
*/
char *fname_tmp;
/**
* The file pointer for fname_tmp.
*/
FILE *file;
} OutputFile;
/**
* Opens an output file. It is equivalent to <code>fopen(fname, "w");</code>
* but uses a temporary file instead of <code>fname</code> until #of_close() is
* called.
*
* @param of an #OutputFile instance allocated by the caller; it must not be
* freed or reused until #of_close() has been called
*
* @param fname the filename to open; the string may be freed or reused
* afterwards
*
* @return the file pointer or <code>NULL</code> if the file could not be
* opened; in this case an error message has been printed and the original file
* content are unchanged
*/
FILE *of_open(OutputFile *of, const char *fname);
/**
* Closes an output file. This function (or #of_cancel()} must be called
* exactly once for each successful call to #of_open().
*
* @param of the output file instance to operate on
*
* @return whether writing was successful; if unsuccessful an error message has
* been printed and the original file content are unchanged
*/
int of_close(OutputFile *of);
/**
* Cancels a save process. This closes and deletes the temporary file, leaving
* the original file contents unmodified. This function (or on_close()} must
* be called exactly once for each successful call to op_open().
*
* @param of the output file instance to operate on
*/
void of_cancel(OutputFile *of);
#endif
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