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yap-6.3/C/ypstdio.c

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/*************************************************************************
* *
* YAP Prolog %W% %G%
* *
* Yap Prolog was developed at NCCUP - Universidade do Porto *
* *
* Copyright L.Damas, V.S.Costa and Universidade do Porto 1985-1997 *
* *
**************************************************************************
* *
* File: io.h *
* Last rev: 19/2/88 *
* mods: *
* comments: simple replacement for stdio *
* *
*************************************************************************/
#include "Yap.h"
#ifdef YAP_STDIO
#include <malloc.h>
#if HAVE_FCNTL_H
#include <fcntl.h>
#endif
#if HAVE_UNISTD_H
#include <unistd.h>
#endif
#if WINDOWS
#include <io.h>
#endif
#include <stdarg.h>
#ifndef O_BINARY
#define O_BINARY 0
#endif
YP_FILE yp_iob[YP_MAX_FILES];
static void
clear_iob(YP_FILE *f)
{
f->flags = f->cnt = 0;
f->buflen = 1;
f->ptr = f->base = (char *) &f->buf;
f->close = close;
f->read = read;
f->write = write;
}
void
init_yp_stdio()
{
int i;
/* mark all descriptors as free */
for(i=0; i<YP_MAX_FILES; ++i) {
yp_iob[i].check = i;
clear_iob(&yp_iob[i]);
}
/* initialize standard ones */
yp_iob[0].fd = 0;
yp_iob[0].flags = _YP_IO_FILE | _YP_IO_READ;
yp_iob[1].fd = 1;
yp_iob[1].flags = _YP_IO_FILE | _YP_IO_WRITE;
yp_iob[2].fd = 2;
yp_iob[2].flags = _YP_IO_FILE | _YP_IO_WRITE;
}
int
YP_fillbuf(YP_FILE *f)
{
if (!(f->flags & _YP_IO_READ)||(f->flags & (_YP_IO_ERR|_YP_IO_EOF)))
return -1;
if ((f->cnt = (f->read)(f->fd,f->base,f->buflen)) < 0) {
f->flags |= _YP_IO_ERR;
return -1;
}
if (f->cnt==0) {
f->flags |= _YP_IO_EOF;
return -1;
}
f->ptr = f->base;
return YP_getc(f);
}
int
YP_flushbuf(int c,YP_FILE *f)
{
if(!(f->flags & _YP_IO_WRITE)||(f->flags & _YP_IO_ERR)) return -1;
*(f->ptr++) = c;
{
int cnt = f->ptr-f->base;
int r = (f->write)(f->fd,f->base,cnt);
f->ptr = f->base;
if (r!=cnt) {
f->flags |= _YP_IO_ERR;
return -1;
}
f->ptr = f->base;
f->cnt = f->buflen-1;
}
return c;
}
int
YP_fflush(YP_FILE *f)
{
if(!(f->flags & _YP_IO_WRITE)||(f->flags & _YP_IO_ERR)) return -1;
if (f->ptr==f->base) return 0;
{
int cnt = f->ptr-f->base;
int r = (f->write)(f->fd,f->base,cnt);
f->ptr = f->base;
if (r!=cnt) {
f->flags |= _YP_IO_ERR;
return -1;
}
f->ptr = f->base;
f->cnt = f->buflen-1;
}
return 0;
}
int
YP_fputs(char *s, YP_FILE *f)
{
int count = 0;
while (*s) {
if (YP_putc(*s++,f)<0) return -1;
++count;
}
return count;
}
int
YP_puts(char *s)
{
return YP_fputs(s,YP_stdout);
}
char *
YP_fgets(char *s, int n, YP_FILE *f)
{
char *p=s;
if (f->flags & _YP_IO_ERR) return 0;
while(--n) {
int ch = YP_getc(f);
if (ch<0) return 0;
*p++ = ch;
if (ch=='\n') break;
}
*p = 0;
return s;
}
char *
YP_gets(char *s)
{
char *p=s;
while(1) {
int ch = YP_getchar();
if (ch<0) return 0;
if (ch=='\n') break;
*p++ = ch;
}
*p = 0;
return s;
}
YP_FILE*
YP_fopen(char *path, char *mode)
{
YP_FILE *f = 0;
int i, fd, flags, ch1, ch2;
for(i=3; i<YP_MAX_FILES; ++i)
if (!yp_iob[i].flags) {
f = &yp_iob[i];
break;
}
if (!f) return f;
/* try to open the file */
flags = 0;
ch1 = *mode++;
ch2 = *mode;
if(ch2=='b') {
flags = O_BINARY;
ch2 = *++mode;
}
if (ch2) return 0;
switch (ch1) {
case 'r':
flags |= O_RDONLY;
break;
case 'w':
flags |= O_WRONLY | O_TRUNC | O_CREAT;
break;
case 'a':
flags |= O_WRONLY | O_CREAT | O_APPEND;
break;
default:
return 0;
}
if ((fd=open(path,flags,0644))<0) return 0;
f->fd = fd;
f->flags = _YP_IO_FILE | (ch1=='r' ? _YP_IO_READ : _YP_IO_WRITE);
f->ptr = f->base;
/* todo: add buffers */
f->cnt = 0;
f->close = close;
f->read = read;
f->write = write;
return f;
}
int
YP_fclose(YP_FILE *f)
{
if (f != &yp_iob[f->check]) return -1;
if (f->flags & _YP_IO_WRITE) {
YP_fflush(f);
}
(f->close)(f->fd);
/* todo: release buffers */
clear_iob(f);
return 0;
}
#define MAXBSIZE 32768
int
YP_printf(char *format,...)
{
va_list ap;
char *buf = (char *) alloca(MAXBSIZE);
int r;
va_start(ap,format);
vsprintf(buf,format,ap);
r = YP_puts(buf);
va_end(ap);
return r;
}
int
YP_fprintf(YP_FILE *f, char *format,...)
{
va_list ap;
char *buf = (char *) alloca(MAXBSIZE);
int r;
va_start(ap,format);
vsprintf(buf,format,ap);
r = YP_fputs(buf,f);
va_end(ap);
return r;
}
int
YP_fileno(YP_FILE *f)
{
return f->fd;
}
int
YP_clearerr(YP_FILE *f)
{
f->flags &= ~ _YP_IO_ERR | _YP_IO_EOF;
return 0;
}
int
YP_feof(YP_FILE *f)
{
return f->flags & _YP_IO_EOF ? 1 : 0;
}
int
YP_setbuf(YP_FILE *f, char *b)
{
return 0;
}
int
YP_fseek(YP_FILE *f, int offset, int whence)
{
/* todo: implement fseek */
return 0;
}
int
YP_ftell(YP_FILE*f)
{
return 0;
}
#endif /* YAP_STDIO */