128 lines
2.9 KiB
C
128 lines
2.9 KiB
C
/* This file contains the code for doing the scsh file ports stuff.
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** Copyright (c) 1993, 1994 by Olin Shivers.
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**
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** Note that this code mutates Scheme records -- it has the layout
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** of fdports and their data records wired in. This is somewhat fragile.
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*/
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/* A note on the clearerr() calls herein: SunOS stdio input routines,
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** contrary to POSIX, will return EOF if the stream's EOF flag is set,
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** without trying to read the stream. This is a lose for tty's, which
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** can frequently still be read from after the first EOF (e.g., if you
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** type a ^D to bag out of a breakpoint, you would like the terminal
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** input port to not shut down forever.)
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**
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** To fix this lossage, we are careful to call clearerr() before every
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** input stream op.
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*/
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#include "sysdep.h"
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#include <stdio.h>
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#include <fcntl.h>
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#include <unistd.h>
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#include <stdlib.h>
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#include <errno.h>
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#include "cstuff.h"
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#define NUM_FDPORTS 256
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#include "fdports.h"
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/* Make sure our exports match up w/the implementation: */
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#include "fdports1.h"
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extern int errno;
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static char const *fdes_modestr(int fd)
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{
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int flags = fcntl(fd,F_GETFL);
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if( flags == -1 ) return NULL;
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flags &= O_ACCMODE;
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if( flags == O_WRONLY ) return "w";
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else if( flags == O_RDONLY ) return "r";
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else if( flags == O_RDWR ) return "r+";
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fputs("That's impossible.\n", stderr);
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abort();
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_exit(-1);
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/*NOTREACHED*/
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}
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/* The two following routines are for delimited read. */
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s48_value read_delim(const char *delims, char *buf,
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int fd, int start, int end,
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int *nread)
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{
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char *cptr = buf+start, /* Location of last char deposited. */
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*bufend = buf+end -1; /* Last writeable position. */
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int retval;
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char c;
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while( 1 ) {
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retval = read( fd, &c, 1 );
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if( retval == 0 ) { /* Terminal case: EOF. */
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*nread = cptr - buf - start;
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return S48_EOF;
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}
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else if( retval == -1 ) { /* Terminal case: error. */
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*nread = cptr - buf - start;
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return s48_enter_integer(errno);
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}
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else if( delims[c] ) { /* Terminal case: delimiter char. */
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*nread = cptr - buf - start;
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return s48_enter_char(c);
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}
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else if( cptr == bufend ) { /* Terminal case: buffer overflow. */
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*cptr = c;
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*nread = end-start;
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return S48_FALSE;
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}
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else if ( cptr > bufend ){
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fputs("cptr > bufend.\n", stderr);
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abort();
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_exit(-1);
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}
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else {
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*cptr++ = c;
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}
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}
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}
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s48_value skip_chars(const char *skipchars, int fd, int *nread)
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{
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int nr = 0; /* Number of skip chars read. */
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char c;
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while( 1 ) {
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int retval = read ( fd, &c, 1 );
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if( retval == 0 ) { /* Terminal case: EOF. */
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*nread = nr;
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return S48_FALSE;
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}
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if( retval == -1 ) { /* Terminal case: error. */
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*nread = nr;
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return s48_enter_integer(errno);
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}
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else if( !skipchars[c] ) { /* Terminal case: non-skip char. */
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*nread = nr;
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return s48_enter_char(c);
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}
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nr++;
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}
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}
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