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files.c
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C/C++ Source or Header
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1993-01-23
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3KB
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150 lines
/**************************************************************************
* files.c: File open/close, input/output, etc.
* Part of MP, the MIDI Playground.
*
* Author: Daniel Barrett
* Version: See the file "version.h".
* Copyright: None! This program is in the Public Domain.
* Please share it with others.
***************************************************************************/
#include <stdio.h>
#include <exec/types.h>
#include <libraries/dos.h>
#include <libraries/dosextens.h>
/* Open a file and return a pointer to it. */
FILE *OpenAFile(char *filename, char *mode, char *readOrWrite)
{
FILE *fp;
if ((fp = fopen(filename, mode)) == NULL)
fprintf(stderr, "Cannot %s the file \"%s\",\n",
readOrWrite, filename);
return(fp);
}
/* Open a file for reading. We might also have a macro with the same name,
* so we used ifdef's. */
#ifndef OpenReadFile
FILE *OpenReadFile(char *filename)
{
return(OpenAFile(filename, "r", "read"));
}
#endif
/* Open a file for writing. We might also have a macro with the same name,
* so we used ifdef's. */
#ifndef OpenWriteFile
FILE *OpenWriteFile(char *filename)
{
return(OpenAFile(filename, "w", "write"));
}
#endif
/* Tell me whether or not a file exists. */
BOOL FileExists(char *filename)
{
BPTR lock;
if ((lock = Lock(filename, ACCESS_READ)) != NULL)
{
UnLock(lock);
return(TRUE);
}
return(FALSE);
}
/* See if we want to overwrite an existing file. */
/* BUFSIZ is too large, perhaps -- change later -- but don't compromise
* on correct reading of the user's input. Too small, and extra unread
* chars are read on the NEXT call (yuck). If you use gets(), too much
* input crashes the program. */
BOOL DontOverwriteExistingFile(char *filename)
{
char buf[BUFSIZ];
BOOL safety = TRUE;
if (FileExists(filename))
{
fprintf(stderr,
"File \"%s\" already exists.\nOVERWRITE it? [%s]: ",
filename, "Yes/No, RETURN=No");
fflush(stderr);
if (fgets(buf, BUFSIZ-1, stdin))
safety = (toupper(buf[0]) != 'Y');
else
safety = TRUE;
}
else
safety = FALSE; /* File doesn't exist. */
if (safety)
fprintf(stderr, "%s not overwritten.\n\n", filename);
return(safety);
}
/* Open the input and output files.
* We open input AFTER output in case the user has specified CON: windows,
* so the input window is the active one. */
BOOL SetupFiles(char *infile, char *outfile, FILE **in, FILE **out)
{
if (!outfile || (outfile[0] == '\0'))
*out = stdout;
else if (DontOverwriteExistingFile(outfile))
return(FALSE);
else if ((*out = OpenWriteFile(outfile)) == NULL)
return(FALSE);
if (!infile || (infile[0] == '\0'))
*in = stdin;
else if ((*in = OpenReadFile(infile)) == NULL)
return(FALSE);
return(TRUE);
}
/* Close the files used by the program, and deallocate the arrays used
* for storing the filenames. */
void CloseFiles(FILE *in, FILE *out, char *filein, char *fileout)
{
if (in && (in != stdin)) fclose(in);
if (out && (out != stdout)) fclose(out);
if (filein) free(filein);
if (fileout) free(fileout);
}
/* Allocate space to store a filename, and copy the contents of "src" into
* it. */
BOOL MakeFilename(char **dest, char *src)
{
if ((!src) || (*src == '\0')
|| ((*dest = (char *)malloc(strlen(src)+1)) == NULL))
return(FALSE);
else
{
strcpy(*dest, src);
return(TRUE);
}
}