source: buchla-68k/libcio/fopen.c@ c80943f

/*
   =============================================================================
        fopen.c -- open a stream file for the Buchla 700 C I/O Library
        Version 4 -- 1987-06-30 -- D.N. Lynx Crowe
   =============================================================================
*/

#include "ram.h"

FILE *_opener(int8_t *name, int8_t *mode, int16_t aflag)
{
        register FILE *fp;
        register int16_t plusopt;

        fp = Cbuffs;

        while ( fp->_flags ) {

                if ( ++fp GE (Cbuffs + NSTREAMS))
                        return(NULL);
        }

        plusopt = mode[1] EQ '+';

        switch (0x007F & *mode) {

        case 'r':       /* read mode */
                if ((fp->_unit = open(name, (plusopt ? O_RDWR : O_RDONLY), aflag)) EQ -1)
                        return(NULL);
                break;

        case 'w':       /* write mode */
                if ((fp->_unit = open(name, (plusopt ? O_RDWR : O_WRONLY)|O_CREAT|O_TRUNC, aflag)) EQ -1)
                        return(NULL);

                break;
        
        case 'a':       /* append mode */
                if ((fp->_unit = open(name, (plusopt ? O_RDWR : O_WRONLY)|O_CREAT, aflag)) EQ -1)
                        return(NULL);

                if (lseek(fp->_unit, 0L, 2) < 0) {

                        close(fp->_unit);
                        return(NULL);           /* couldn't append */
                }

                break;

        default:
                errno = EINVAL;
                return(NULL);
        }

        fp->_flags  = _BUSY;
        fp->_buflen = BUFSIZ;
        fp->_buff   = 0; 
        fp->_bend   = 0; /* nothing in buffer */
        fp->_bp     = 0;
        return(fp);
}

FILE *fopen(int8_t *name, int8_t *mode)
{
        return(_opener(name, mode, 0));
}

FILE *fopena(int8_t *name, int8_t *mode)
{
        return(_opener(name, mode, 0));
}

FILE *fopenb(int8_t *name, int8_t *mode)
{
        return(_opener(name, mode, O_RAW));
}