271 lines
6.8 KiB
C
271 lines
6.8 KiB
C
/* Copyright (C) 2008, 2009, 2010 Free Software Foundation, Inc.
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Contributed by Janne Blomqvist
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This file is part of the GNU Fortran runtime library (libgfortran).
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Libgfortran is free software; you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation; either version 3, or (at your option)
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any later version.
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Libgfortran is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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Under Section 7 of GPL version 3, you are granted additional
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permissions described in the GCC Runtime Library Exception, version
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3.1, as published by the Free Software Foundation.
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You should have received a copy of the GNU General Public License and
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a copy of the GCC Runtime Library Exception along with this program;
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see the files COPYING3 and COPYING.RUNTIME respectively. If not, see
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<http://www.gnu.org/licenses/>. */
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#include "io.h"
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#include "fbuf.h"
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#include "unix.h"
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#include <string.h>
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#include <stdlib.h>
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//#define FBUF_DEBUG
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void
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fbuf_init (gfc_unit * u, int len)
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{
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if (len == 0)
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len = 512; /* Default size. */
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u->fbuf = get_mem (sizeof (struct fbuf));
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u->fbuf->buf = get_mem (len);
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u->fbuf->len = len;
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u->fbuf->act = u->fbuf->pos = 0;
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}
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void
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fbuf_destroy (gfc_unit * u)
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{
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if (u->fbuf == NULL)
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return;
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if (u->fbuf->buf)
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free (u->fbuf->buf);
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free (u->fbuf);
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u->fbuf = NULL;
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}
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static void
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#ifdef FBUF_DEBUG
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fbuf_debug (gfc_unit * u, const char * format, ...)
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{
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va_list args;
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va_start(args, format);
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vfprintf(stderr, format, args);
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va_end(args);
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fprintf (stderr, "fbuf_debug pos: %d, act: %d, buf: ''",
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u->fbuf->pos, u->fbuf->act);
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for (int ii = 0; ii < u->fbuf->act; ii++)
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{
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putc (u->fbuf->buf[ii], stderr);
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}
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fprintf (stderr, "''\n");
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}
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#else
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fbuf_debug (gfc_unit * u __attribute__ ((unused)),
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const char * format __attribute__ ((unused)),
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...) {}
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#endif
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/* You should probably call this before doing a physical seek on the
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underlying device. Returns how much the physical position was
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modified. */
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int
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fbuf_reset (gfc_unit * u)
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{
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int seekval = 0;
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if (!u->fbuf)
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return 0;
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fbuf_debug (u, "fbuf_reset: ");
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fbuf_flush (u, u->mode);
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/* If we read past the current position, seek the underlying device
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back. */
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if (u->mode == READING && u->fbuf->act > u->fbuf->pos)
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{
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seekval = - (u->fbuf->act - u->fbuf->pos);
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fbuf_debug (u, "fbuf_reset seekval %d, ", seekval);
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}
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u->fbuf->act = u->fbuf->pos = 0;
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return seekval;
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}
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/* Return a pointer to the current position in the buffer, and increase
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the pointer by len. Makes sure that the buffer is big enough,
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reallocating if necessary. */
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char *
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fbuf_alloc (gfc_unit * u, int len)
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{
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int newlen;
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char *dest;
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fbuf_debug (u, "fbuf_alloc len %d, ", len);
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if (u->fbuf->pos + len > u->fbuf->len)
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{
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/* Round up to nearest multiple of the current buffer length. */
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newlen = ((u->fbuf->pos + len) / u->fbuf->len + 1) * u->fbuf->len;
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dest = realloc (u->fbuf->buf, newlen);
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if (dest == NULL)
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return NULL;
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u->fbuf->buf = dest;
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u->fbuf->len = newlen;
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}
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dest = u->fbuf->buf + u->fbuf->pos;
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u->fbuf->pos += len;
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if (u->fbuf->pos > u->fbuf->act)
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u->fbuf->act = u->fbuf->pos;
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return dest;
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}
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/* mode argument is WRITING for write mode and READING for read
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mode. Return value is 0 for success, -1 on failure. */
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int
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fbuf_flush (gfc_unit * u, unit_mode mode)
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{
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int nwritten;
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if (!u->fbuf)
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return 0;
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fbuf_debug (u, "fbuf_flush with mode %d: ", mode);
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if (mode == WRITING)
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{
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if (u->fbuf->pos > 0)
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{
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nwritten = swrite (u->s, u->fbuf->buf, u->fbuf->pos);
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if (nwritten < 0)
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return -1;
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}
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}
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/* Salvage remaining bytes for both reading and writing. This
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happens with the combination of advance='no' and T edit
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descriptors leaving the final position somewhere not at the end
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of the record. For reading, this also happens if we sread() past
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the record boundary. */
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if (u->fbuf->act > u->fbuf->pos && u->fbuf->pos > 0)
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memmove (u->fbuf->buf, u->fbuf->buf + u->fbuf->pos,
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u->fbuf->act - u->fbuf->pos);
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u->fbuf->act -= u->fbuf->pos;
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u->fbuf->pos = 0;
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return 0;
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}
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int
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fbuf_seek (gfc_unit * u, int off, int whence)
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{
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if (!u->fbuf)
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return -1;
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switch (whence)
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{
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case SEEK_SET:
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break;
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case SEEK_CUR:
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off += u->fbuf->pos;
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break;
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case SEEK_END:
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off += u->fbuf->act;
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break;
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default:
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return -1;
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}
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fbuf_debug (u, "fbuf_seek, off %d ", off);
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/* The start of the buffer is always equal to the left tab
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limit. Moving to the left past the buffer is illegal in C and
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would also imply moving past the left tab limit, which is never
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allowed in Fortran. Similarly, seeking past the end of the buffer
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is not possible, in that case the user must make sure to allocate
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space with fbuf_alloc(). So return error if that is
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attempted. */
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if (off < 0 || off > u->fbuf->act)
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return -1;
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u->fbuf->pos = off;
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return off;
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}
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/* Fill the buffer with bytes for reading. Returns a pointer to start
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reading from. If we hit EOF, returns a short read count. If any
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other error occurs, return NULL. After reading, the caller is
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expected to call fbuf_seek to update the position with the number
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of bytes actually processed. */
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char *
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fbuf_read (gfc_unit * u, int * len)
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{
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char *ptr;
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int oldact, oldpos;
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int readlen = 0;
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fbuf_debug (u, "fbuf_read, len %d: ", *len);
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oldact = u->fbuf->act;
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oldpos = u->fbuf->pos;
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ptr = fbuf_alloc (u, *len);
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u->fbuf->pos = oldpos;
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if (oldpos + *len > oldact)
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{
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fbuf_debug (u, "reading %d bytes starting at %d ",
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oldpos + *len - oldact, oldact);
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readlen = sread (u->s, u->fbuf->buf + oldact, oldpos + *len - oldact);
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if (readlen < 0)
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return NULL;
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*len = oldact - oldpos + readlen;
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}
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u->fbuf->act = oldact + readlen;
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fbuf_debug (u, "fbuf_read done: ");
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return ptr;
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}
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/* When the fbuf_getc() inline function runs out of buffer space, it
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calls this function to fill the buffer with bytes for
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reading. Never call this function directly. */
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int
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fbuf_getc_refill (gfc_unit * u)
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{
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int nread;
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char *p;
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fbuf_debug (u, "fbuf_getc_refill ");
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/* Read 80 bytes (average line length?). This is a compromise
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between not needing to call the read() syscall all the time and
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not having to memmove unnecessary stuff when switching to the
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next record. */
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nread = 80;
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p = fbuf_read (u, &nread);
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if (p && nread > 0)
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return (unsigned char) u->fbuf->buf[u->fbuf->pos++];
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else
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return EOF;
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}
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