407 lines
9.4 KiB
C
407 lines
9.4 KiB
C
/* Copyright (C) 2002-2003, 2005, 2006, 2007, 2009 Free Software Foundation, Inc.
|
|
Contributed by Andy Vaught and Janne Blomqvist
|
|
|
|
This file is part of the GNU Fortran runtime library (libgfortran).
|
|
|
|
Libgfortran is free software; you can redistribute it and/or modify
|
|
it under the terms of the GNU General Public License as published by
|
|
the Free Software Foundation; either version 3, or (at your option)
|
|
any later version.
|
|
|
|
Libgfortran is distributed in the hope that it will be useful,
|
|
but WITHOUT ANY WARRANTY; without even the implied warranty of
|
|
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
|
|
GNU General Public License for more details.
|
|
|
|
Under Section 7 of GPL version 3, you are granted additional
|
|
permissions described in the GCC Runtime Library Exception, version
|
|
3.1, as published by the Free Software Foundation.
|
|
|
|
You should have received a copy of the GNU General Public License and
|
|
a copy of the GCC Runtime Library Exception along with this program;
|
|
see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
|
|
<http://www.gnu.org/licenses/>. */
|
|
|
|
#include "io.h"
|
|
#include "fbuf.h"
|
|
#include "unix.h"
|
|
#include <string.h>
|
|
|
|
/* file_pos.c-- Implement the file positioning statements, i.e. BACKSPACE,
|
|
ENDFILE, and REWIND as well as the FLUSH statement. */
|
|
|
|
|
|
/* formatted_backspace(fpp, u)-- Move the file back one line. The
|
|
current position is after the newline that terminates the previous
|
|
record, and we have to sift backwards to find the newline before
|
|
that or the start of the file, whichever comes first. */
|
|
|
|
static const int READ_CHUNK = 4096;
|
|
|
|
static void
|
|
formatted_backspace (st_parameter_filepos *fpp, gfc_unit *u)
|
|
{
|
|
gfc_offset base;
|
|
char p[READ_CHUNK];
|
|
ssize_t n;
|
|
|
|
base = stell (u->s) - 1;
|
|
|
|
do
|
|
{
|
|
n = (base < READ_CHUNK) ? base : READ_CHUNK;
|
|
base -= n;
|
|
if (sseek (u->s, base, SEEK_SET) < 0)
|
|
goto io_error;
|
|
if (sread (u->s, p, n) != n)
|
|
goto io_error;
|
|
|
|
/* We have moved backwards from the current position, it should
|
|
not be possible to get a short read. Because it is not
|
|
clear what to do about such thing, we ignore the possibility. */
|
|
|
|
/* There is no memrchr() in the C library, so we have to do it
|
|
ourselves. */
|
|
|
|
while (n > 0)
|
|
{
|
|
n--;
|
|
if (p[n] == '\n')
|
|
{
|
|
base += n + 1;
|
|
goto done;
|
|
}
|
|
}
|
|
|
|
}
|
|
while (base != 0);
|
|
|
|
/* base is the new pointer. Seek to it exactly. */
|
|
done:
|
|
if (sseek (u->s, base, SEEK_SET) < 0)
|
|
goto io_error;
|
|
u->last_record--;
|
|
u->endfile = NO_ENDFILE;
|
|
|
|
return;
|
|
|
|
io_error:
|
|
generate_error (&fpp->common, LIBERROR_OS, NULL);
|
|
}
|
|
|
|
|
|
/* unformatted_backspace(fpp) -- Move the file backwards for an unformatted
|
|
sequential file. We are guaranteed to be between records on entry and
|
|
we have to shift to the previous record. Loop over subrecords. */
|
|
|
|
static void
|
|
unformatted_backspace (st_parameter_filepos *fpp, gfc_unit *u)
|
|
{
|
|
gfc_offset m, slen;
|
|
GFC_INTEGER_4 m4;
|
|
GFC_INTEGER_8 m8;
|
|
ssize_t length;
|
|
int continued;
|
|
char p[sizeof (GFC_INTEGER_8)];
|
|
|
|
if (compile_options.record_marker == 0)
|
|
length = sizeof (GFC_INTEGER_4);
|
|
else
|
|
length = compile_options.record_marker;
|
|
|
|
do
|
|
{
|
|
slen = - (gfc_offset) length;
|
|
if (sseek (u->s, slen, SEEK_CUR) < 0)
|
|
goto io_error;
|
|
if (sread (u->s, p, length) != length)
|
|
goto io_error;
|
|
|
|
/* Only GFC_CONVERT_NATIVE and GFC_CONVERT_SWAP are valid here. */
|
|
if (likely (u->flags.convert == GFC_CONVERT_NATIVE))
|
|
{
|
|
switch (length)
|
|
{
|
|
case sizeof(GFC_INTEGER_4):
|
|
memcpy (&m4, p, sizeof (m4));
|
|
m = m4;
|
|
break;
|
|
|
|
case sizeof(GFC_INTEGER_8):
|
|
memcpy (&m8, p, sizeof (m8));
|
|
m = m8;
|
|
break;
|
|
|
|
default:
|
|
runtime_error ("Illegal value for record marker");
|
|
break;
|
|
}
|
|
}
|
|
else
|
|
{
|
|
switch (length)
|
|
{
|
|
case sizeof(GFC_INTEGER_4):
|
|
reverse_memcpy (&m4, p, sizeof (m4));
|
|
m = m4;
|
|
break;
|
|
|
|
case sizeof(GFC_INTEGER_8):
|
|
reverse_memcpy (&m8, p, sizeof (m8));
|
|
m = m8;
|
|
break;
|
|
|
|
default:
|
|
runtime_error ("Illegal value for record marker");
|
|
break;
|
|
}
|
|
|
|
}
|
|
|
|
continued = m < 0;
|
|
if (continued)
|
|
m = -m;
|
|
|
|
if (sseek (u->s, -m -2 * length, SEEK_CUR) < 0)
|
|
goto io_error;
|
|
} while (continued);
|
|
|
|
u->last_record--;
|
|
return;
|
|
|
|
io_error:
|
|
generate_error (&fpp->common, LIBERROR_OS, NULL);
|
|
}
|
|
|
|
|
|
extern void st_backspace (st_parameter_filepos *);
|
|
export_proto(st_backspace);
|
|
|
|
void
|
|
st_backspace (st_parameter_filepos *fpp)
|
|
{
|
|
gfc_unit *u;
|
|
|
|
library_start (&fpp->common);
|
|
|
|
u = find_unit (fpp->common.unit);
|
|
if (u == NULL)
|
|
{
|
|
generate_error (&fpp->common, LIBERROR_BAD_UNIT, NULL);
|
|
goto done;
|
|
}
|
|
|
|
/* Direct access is prohibited, and so is unformatted stream access. */
|
|
|
|
|
|
if (u->flags.access == ACCESS_DIRECT)
|
|
{
|
|
generate_error (&fpp->common, LIBERROR_OPTION_CONFLICT,
|
|
"Cannot BACKSPACE a file opened for DIRECT access");
|
|
goto done;
|
|
}
|
|
|
|
if (u->flags.access == ACCESS_STREAM && u->flags.form == FORM_UNFORMATTED)
|
|
{
|
|
generate_error (&fpp->common, LIBERROR_OPTION_CONFLICT,
|
|
"Cannot BACKSPACE an unformatted stream file");
|
|
goto done;
|
|
}
|
|
|
|
/* Make sure format buffer is flushed and reset. */
|
|
if (u->flags.form == FORM_FORMATTED)
|
|
{
|
|
int pos = fbuf_reset (u);
|
|
if (pos != 0)
|
|
sseek (u->s, pos, SEEK_CUR);
|
|
}
|
|
|
|
|
|
/* Check for special cases involving the ENDFILE record first. */
|
|
|
|
if (u->endfile == AFTER_ENDFILE)
|
|
{
|
|
u->endfile = AT_ENDFILE;
|
|
u->flags.position = POSITION_APPEND;
|
|
sflush (u->s);
|
|
}
|
|
else
|
|
{
|
|
if (stell (u->s) == 0)
|
|
{
|
|
u->flags.position = POSITION_REWIND;
|
|
goto done; /* Common special case */
|
|
}
|
|
|
|
if (u->mode == WRITING)
|
|
{
|
|
/* If there are previously written bytes from a write with
|
|
ADVANCE="no", add a record marker before performing the
|
|
BACKSPACE. */
|
|
|
|
if (u->previous_nonadvancing_write)
|
|
finish_last_advance_record (u);
|
|
|
|
u->previous_nonadvancing_write = 0;
|
|
|
|
unit_truncate (u, stell (u->s), &fpp->common);
|
|
u->mode = READING;
|
|
}
|
|
|
|
if (u->flags.form == FORM_FORMATTED)
|
|
formatted_backspace (fpp, u);
|
|
else
|
|
unformatted_backspace (fpp, u);
|
|
|
|
u->flags.position = POSITION_UNSPECIFIED;
|
|
u->endfile = NO_ENDFILE;
|
|
u->current_record = 0;
|
|
u->bytes_left = 0;
|
|
}
|
|
|
|
done:
|
|
if (u != NULL)
|
|
unlock_unit (u);
|
|
|
|
library_end ();
|
|
}
|
|
|
|
|
|
extern void st_endfile (st_parameter_filepos *);
|
|
export_proto(st_endfile);
|
|
|
|
void
|
|
st_endfile (st_parameter_filepos *fpp)
|
|
{
|
|
gfc_unit *u;
|
|
|
|
library_start (&fpp->common);
|
|
|
|
u = find_unit (fpp->common.unit);
|
|
if (u != NULL)
|
|
{
|
|
if (u->flags.access == ACCESS_DIRECT)
|
|
{
|
|
generate_error (&fpp->common, LIBERROR_OPTION_CONFLICT,
|
|
"Cannot perform ENDFILE on a file opened"
|
|
" for DIRECT access");
|
|
goto done;
|
|
}
|
|
|
|
/* If there are previously written bytes from a write with ADVANCE="no",
|
|
add a record marker before performing the ENDFILE. */
|
|
|
|
if (u->previous_nonadvancing_write)
|
|
finish_last_advance_record (u);
|
|
|
|
u->previous_nonadvancing_write = 0;
|
|
|
|
if (u->current_record)
|
|
{
|
|
st_parameter_dt dtp;
|
|
dtp.common = fpp->common;
|
|
memset (&dtp.u.p, 0, sizeof (dtp.u.p));
|
|
dtp.u.p.current_unit = u;
|
|
next_record (&dtp, 1);
|
|
}
|
|
|
|
unit_truncate (u, stell (u->s), &fpp->common);
|
|
u->endfile = AFTER_ENDFILE;
|
|
if (0 == stell (u->s))
|
|
u->flags.position = POSITION_REWIND;
|
|
done:
|
|
unlock_unit (u);
|
|
}
|
|
|
|
library_end ();
|
|
}
|
|
|
|
|
|
extern void st_rewind (st_parameter_filepos *);
|
|
export_proto(st_rewind);
|
|
|
|
void
|
|
st_rewind (st_parameter_filepos *fpp)
|
|
{
|
|
gfc_unit *u;
|
|
|
|
library_start (&fpp->common);
|
|
|
|
u = find_unit (fpp->common.unit);
|
|
if (u != NULL)
|
|
{
|
|
if (u->flags.access == ACCESS_DIRECT)
|
|
generate_error (&fpp->common, LIBERROR_BAD_OPTION,
|
|
"Cannot REWIND a file opened for DIRECT access");
|
|
else
|
|
{
|
|
/* If there are previously written bytes from a write with ADVANCE="no",
|
|
add a record marker before performing the ENDFILE. */
|
|
|
|
if (u->previous_nonadvancing_write)
|
|
finish_last_advance_record (u);
|
|
|
|
u->previous_nonadvancing_write = 0;
|
|
|
|
fbuf_reset (u);
|
|
|
|
u->last_record = 0;
|
|
|
|
if (sseek (u->s, 0, SEEK_SET) < 0)
|
|
generate_error (&fpp->common, LIBERROR_OS, NULL);
|
|
|
|
/* Handle special files like /dev/null differently. */
|
|
if (!is_special (u->s))
|
|
{
|
|
/* We are rewinding so we are not at the end. */
|
|
u->endfile = NO_ENDFILE;
|
|
}
|
|
else
|
|
{
|
|
/* Set this for compatibilty with g77 for /dev/null. */
|
|
if (file_length (u->s) == 0 && stell (u->s) == 0)
|
|
u->endfile = AT_ENDFILE;
|
|
/* Future refinements on special files can go here. */
|
|
}
|
|
|
|
u->current_record = 0;
|
|
u->strm_pos = 1;
|
|
u->read_bad = 0;
|
|
}
|
|
/* Update position for INQUIRE. */
|
|
u->flags.position = POSITION_REWIND;
|
|
unlock_unit (u);
|
|
}
|
|
|
|
library_end ();
|
|
}
|
|
|
|
|
|
extern void st_flush (st_parameter_filepos *);
|
|
export_proto(st_flush);
|
|
|
|
void
|
|
st_flush (st_parameter_filepos *fpp)
|
|
{
|
|
gfc_unit *u;
|
|
|
|
library_start (&fpp->common);
|
|
|
|
u = find_unit (fpp->common.unit);
|
|
if (u != NULL)
|
|
{
|
|
/* Make sure format buffer is flushed. */
|
|
if (u->flags.form == FORM_FORMATTED)
|
|
fbuf_flush (u, u->mode);
|
|
|
|
sflush (u->s);
|
|
unlock_unit (u);
|
|
}
|
|
else
|
|
/* FLUSH on unconnected unit is illegal: F95 std., 9.3.5. */
|
|
generate_error (&fpp->common, LIBERROR_BAD_OPTION,
|
|
"Specified UNIT in FLUSH is not connected");
|
|
|
|
library_end ();
|
|
}
|