fcons.c

Go to the documentation of this file.

/* @(#)fcons.c  2.20 10/11/06 Copyright 1986, 1995-2010 J. Schilling */
/*
 *  Copyright (c) 1986, 1995-2010  J. Schilling
 */
/*
 * The contents of this file are subject to the terms of the
 * Common Development and Distribution License, Version 1.0 only
 * (the "License").  You may not use this file except in compliance
 * with the License.
 *
 * See the file CDDL.Schily.txt in this distribution for details.
 *
 * When distributing Covered Code, include this CDDL HEADER in each
 * file and include the License file CDDL.Schily.txt from this distribution.
 */
 
#include "schilyio.h"
 
/*
 * Note that because of a definition in schilyio.h we are using
 * fseeko()/ftello() instead of fseek()/ftell() if available.
 */
 
LOCAL   char    *fmtab[] = {
            "", /* 0    FI_NONE             */
            "r",    /* 1    FI_READ             */
            "w",    /* 2    FI_WRITE        **1)    */
            "r+",   /* 3    FI_READ  | FI_WRITE     */
            "b",    /* 4    FI_NONE  | FI_BINARY        */
            "rb",   /* 5    FI_READ  | FI_BINARY        */
            "wb",   /* 6    FI_WRITE | FI_BINARY    **1)    */
            "r+b",  /* 7    FI_READ  | FI_WRITE | FI_BINARY */
 
/* + FI_APPEND  */  "", /* 0    FI_NONE             */
/* ...      */  "r",    /* 1    FI_READ             */
            "a",    /* 2    FI_WRITE        **1)    */
            "a+",   /* 3    FI_READ  | FI_WRITE     */
            "b",    /* 4    FI_NONE  | FI_BINARY        */
            "rb",   /* 5    FI_READ  | FI_BINARY        */
            "ab",   /* 6    FI_WRITE | FI_BINARY    **1)    */
            "a+b",  /* 7    FI_READ  | FI_WRITE | FI_BINARY */
        };
/*
 * NOTES:
 *  1)  fdopen() guarantees not to create/trunc files in this case
 *
 *  "w" will create/trunc files with fopen()
 *  "a" will create files with fopen()
 */
 
 
EXPORT FILE *
_fcons(fd, f, flag)
    register FILE   *fd;
        int f;
        int flag;
{
    int my_gflag = _io_glflag;
 
    if (fd == (FILE *)NULL)
        fd = fdopen(f,
            fmtab[flag&(FI_READ|FI_WRITE|FI_BINARY | FI_APPEND)]);
 
    if (fd != (FILE *)NULL) {
        if (flag & FI_APPEND) {
            (void) fseek(fd, (off_t)0, SEEK_END);
        }
        if (flag & FI_UNBUF) {
            setbuf(fd, NULL);
            my_gflag |= _JS_IOUNBUF;
        }
        set_my_flag(fd, my_gflag); /* must clear it if fd is reused */
        return (fd);
    }
    if (flag & FI_CLOSE)
        close(f);
 
    return ((FILE *)NULL);
}