stdiobuf.c
Click here to get the file
Size
2.0 kB
-
File type
text/plain
File contents
/*ident "@(#)cls4:lib/stream/stdiobuf.c 1.5" */
/*******************************************************************************
C++ source for the C++ Language System, Release 3.0. This product
is a new release of the original cfront developed in the computer
science research center of AT&T Bell Laboratories.
Copyright (c) 1993 UNIX System Laboratories, Inc.
Copyright (c) 1991, 1992 AT&T and UNIX System Laboratories, Inc.
Copyright (c) 1984, 1989, 1990 AT&T. All Rights Reserved.
THIS IS UNPUBLISHED PROPRIETARY SOURCE CODE of AT&T and UNIX System
Laboratories, Inc. The copyright notice above does not evidence
any actual or intended publication of such source code.
*******************************************************************************/
#include <iostream.h>
#include <stdiostream.h>
int stdiobuf::overflow(int c)
{
if ( fp == 0 || c==EOF) return EOF ;
if ( last_op == ios::in ) {
if ( egptr()!=gptr() ) ungetc(*gptr(),fp) ;
// stdio requires seeks between reads and writes
fseek(fp,0,ios::cur) ;
setg(0,0,0) ;
}
last_op = ios::out ;
return putc(c,fp) ;
}
int stdiobuf::underflow() {
if ( fp == 0 ) return EOF ;
if ( last_op == ios::out ) {
fseek(fp,0,0) ;
}
if ( feof(fp) ) return EOF ;
int c = getc(fp) ;
if ( c == EOF ) return EOF ;
setg(buf,buf,buf+1) ;
buf[0] = c ;
return c ;
}
int stdiobuf::pbackfail(int c)
{
return ungetc(c,fp) ;
}
int stdiobuf::sync()
{
if ( last_op==ios::out ) fflush(fp) ;
else if ( last_op==ios::in && gptr()!=egptr() ) {
ungetc(*gptr(),fp) ;
setg(0,0,0) ;
}
return fseek(fp,0,ios::cur) ;
}
streampos stdiobuf::seekoff(streamoff p,ios::seek_dir d,int)
{
if ( gptr()!=egptr() ) ungetc(*gptr(),fp) ;
setg(0,0,0) ;
return fseek(fp,p,d) ;
}
stdiobuf::stdiobuf(FILE* f) :
fp(f)
{
setbuf((char*)0,0) ;
}
stdiobuf::~stdiobuf()
{
if (fp) fflush(fp) ;
}
stdiostream::stdiostream(FILE* f) : buf(f)
{
init(&buf) ;
}
stdiostream::~stdiostream() { }
stdiobuf* stdiostream::rdbuf() { return &buf ; }