openfile.cxx

//==============================================================================
// File:        openfile.cxx
//
// Copyright (c) 2017, Phil Harvey, Queen's University
//==============================================================================
/* file utilites - PH 12/11/98 */

#include <string.h>
#include <stdlib.h>
#include <sys/stat.h>
#include <sys/types.h>
#include "openfile.h"

static char openFileName[FILENAME_LEN];

extern char *   progpath;

/*
** Try to open file first in the default directory,
** then in the directory specified in the command line (progpath --
** where the executable lives), then the specified search directory,
** and finally in all directories of the path statement.
** - The name of the opened file is available from getOpenFileName()
*/
FILE *openFile(char *name, char *mode, char *searchPath)
{
    int     i, n;
    FILE    *fp;
    char    *pt2;
    char    *path;

    /* first try to open the specified file as named */
    strcpy(openFileName,name);
    fp = openPlainFile(openFileName,mode);
    if (!fp) {
        /* remove any path specification from 'name' */
        pt2 = strrchr(name,'/');
        if (pt2) name = pt2 + 1;
        /* look for file in the same directory as the executable */
        if (!fp && progpath) {
            strcpy(openFileName,progpath);
            pt2 = strrchr(openFileName,'/');
            if (pt2) {
                strcpy(pt2+1,name);
                fp = openPlainFile(openFileName,mode);
            }
        }
        /* look for file in 'searchPath' and 'PATH' */
        for (i=0; i<2 && !fp; ++i) {
            if (i==0) {
                path = searchPath;
            } else {
                path = getenv("PATH");
            }
            if (!path) continue;
            for (;;) {
                pt2 = strchr(path,':');
                if (!pt2) pt2 = strchr(path,0);
                n = pt2 - path;
                if (n) {
                    memcpy(openFileName,path,n);
                    /* add trailing '/' if necessary */
                    if (openFileName[n-1] != '/') {
                        openFileName[n++] = '/';
                    }
                    strcpy(openFileName+n,name);
                    fp = openPlainFile(openFileName,mode);
                    if (fp) break;
                }
                if (!(*pt2)) break;
                path = pt2 + 1;
            }
        }
    }
    return(fp);
}

/* creates an alternate file by adding altExt to the name
** - overwrites existing files
** - The name of the opened file is available from getOpenFileName()
*/
FILE *createAltFile(char *name, char *mode, char *altExt)
{
    char    buff[512];
    
    strcpy(buff,name);
    strcat(buff,altExt);
    strcpy(openFileName, buff); /* save new name */
    return(fopen(buff,mode));
}

/* opens an alternate file by adding altExt to the name
** - The name of the opened file is available from getOpenFileName()
*/
FILE *openAltFile(char *name,char *mode,char *searchPath,char *altExt)
{
    char    buff[512];

    strcpy(buff,name);
    strcat(buff,altExt);
    return(openFile(buff,mode,searchPath));
}

/*
** Open a specified file.
** Make sure it is a plain file (not a directory, etc) if opened for reading
*/
FILE *openPlainFile(char *name, char *mode)
{
#ifndef STAT_BUG
    struct stat file_stat;

    if (mode[0]=='r') {
        if (stat(name,&file_stat)) return((FILE *)0);
        if (!(file_stat.st_mode & S_IFREG)) return((FILE *)0);
    }
#endif /* STAT_BUG */
    return(fopen(name,mode));
}

/* get full pathname of last file opened */
char *getOpenFileName(void)
{
    return(openFileName);
}

/* get name of last file opened with path removed */
char *getOpenFileNameNoPath(void)
{
    char *pt = strrchr(openFileName,'/');
    if (pt) ++pt;
    else pt = openFileName;
    return(pt);
}

/* Force a string int `name of last opened file' */
void putOpenFileName( char *p )
{
    strcpy( openFileName, p );
    return;
}