/*
 *  FOPEN.C		fopen freopen fdopen
 *
 *    (c)Copyright 1992-1997 Obvious Implementations Corp.  Redistribution and
 *    use is allowed under the terms of the DICE-LICENSE FILE,
 *    DICE-LICENSE.TXT.
 *
 *  modes:	a[b][+]     append [binary] [+ignored]
 *		r[b][+]     read [binary] [update-allow writes]
 *		w[b][+]     write [binary] [uupdate-allow reads]
 *
 *		a always appends- write only
 *		r file must exist '+' means can write too.
 *		w file always create/truncate
 *		b binary (ignored)
 *
 *		F INTERNAL, user should never specify.	Used by fdopen.
 */

#include <clib/dos_protos.h>
#include <stdio.h>
#include <stdlib.h>
#include <fcntl.h>
#include <errno.h>
#include <string.h>
#include <lib/misc.h>

FILE *
fopen(name, modes)
const char *name;
const char *modes;
{
    FILE *fi = malloc(sizeof(FILE));

    if (fi) {
	_slow_bzero(fi, sizeof(FILE));
	if (freopen(name, modes, fi) == NULL) {
	    free(fi);
	    fi = NULL;
	}
    }
    return(fi);
}

FILE *
fdopen(fd, modes)
int fd;
const char *modes;
{
    char buf[16];

    if (strlen(modes) < 14) {
	buf[0] = 'F';
	strcpy(buf + 1, modes);
	return(fopen((char *)fd, buf));
    }
    return(NULL);
}

FILE *
freopen(name, modes, fi)
const char *name;
const char *modes;
FILE *fi;
{
    short fdmode = 0;
    short fimode = 0;
    short fdOpen = 0;

    if (fi == stdin || fi == stdout || fi == stderr)
	fimode |= __SIF_NOFREE;

    {
	char c;
	while (c = *modes) {
	    if (c == 'r') {
		fdmode |= O_RDONLY;
		fimode |= __SIF_READ;
	    }
	    if (c == 'w') {
		fdmode |= O_WRONLY | O_CREAT | O_TRUNC;
		fimode |= __SIF_WRITE;
	    }
	    if (c == '+') {
		fdmode |= O_RDWR;
		fdmode &= ~(O_RDONLY|O_WRONLY);
		fimode |= __SIF_READ | __SIF_WRITE;
	    }
	    if (c == 'b') {
		fdmode |= O_BINARY;
		fimode |= __SIF_BINARY;
	    }
	    if (c == 'a') {
		fdmode |= O_CREAT | O_APPEND;
		fimode |= __SIF_WRITE | __SIF_APPEND;
	    }
	    if (c == 'F')       /*  INTERNAL    */
		fdOpen = 1;
	    if (c == 'C')       /*  INTERNAL    */
		fimode |= __SIF_REMOVE;
	    ++modes;
	}
    }
    if (fi) {
	if (fi->sd_Flags & __SIF_OPEN) {
	    __fclose(fi);
	    if ( (fimode & __SIF_REMOVE) && (fi->sd_Name))free(fi->sd_Name);
	    // disconnect file handle
	    if ((fi->sd_Flags & __SIF_NOFREE) == 0) {
	        *fi->sd_Prev = fi->sd_Next;
	        if (fi->sd_Next)fi->sd_Next->sd_Prev = fi->sd_Prev;
	    }
	}
	_slow_bzero(fi, sizeof(FILE));
	if (fdOpen)
	    fi->sd_Fd = (int)name;
	else
	    fi->sd_Fd = open(name, fdmode, 0666);

	if (fi->sd_Fd >= 0) {
	    fi->sd_UC = -1;

	    if ((fimode & __SIF_NOFREE) == 0) {
		fi->sd_Next = _Iod;
		fi->sd_Prev = &_Iod;
		if (fi->sd_Next)
		    fi->sd_Next->sd_Prev = &fi->sd_Next;
		_Iod = fi;
	    }
	    {
		long pos = lseek(fi->sd_Fd, 0, 1);

		if (pos >= 0) {
		    fimode |= __SIF_FILE;
		    fi->sd_Offset = pos;
		}
	    }

	    fi->sd_BufSiz = _bufsiz;
	    fi->sd_Flags = __SIF_OPEN | fimode;
	    fi->sd_RLeft = -1;
	    fi->sd_WLeft = -1;
	    if (fimode & __SIF_REMOVE)
		fi->sd_Name = name;	/*  name assumed to be malloc'd */
	} else {
	    return(NULL);
	}
    }
    return(fi);
}