libgfortran/io/fbuf.h

   1 /* Copyright (C) 2009-2023 Free Software Foundation, Inc.
   2    Contributed by Janne Blomqvist
   3
   4 This file is part of the GNU Fortran runtime library (libgfortran).
   5
   6 Libgfortran is free software; you can redistribute it and/or modify
   7 it under the terms of the GNU General Public License as published by
   8 the Free Software Foundation; either version 3, or (at your option)
   9 any later version.
  10
  11 Libgfortran is distributed in the hope that it will be useful,
  12 but WITHOUT ANY WARRANTY; without even the implied warranty of
  13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  14 GNU General Public License for more details.
  15
  16 Under Section 7 of GPL version 3, you are granted additional
  17 permissions described in the GCC Runtime Library Exception, version
  18 3.1, as published by the Free Software Foundation.
  19
  20 You should have received a copy of the GNU General Public License and
  21 a copy of the GCC Runtime Library Exception along with this program;
  22 see the files COPYING3 and COPYING.RUNTIME respectively.  If not, see
  23 <http://www.gnu.org/licenses/>.  */
  24
  25 #ifndef GFOR_FBUF_H
  26 #define GFOR_FBUF_H
  27
  28 #include "io.h"
  29
  30
  31 /* Formatting buffer. This is a temporary scratch buffer used by
  32    formatted read and writes.  After every formatted I/O statement,
  33    this buffer is flushed. This buffer is needed since not all devices
  34    are seekable, and T or TL edit descriptors require moving backwards
  35    in the record.  However, advance='no' complicates the situation, so
  36    the buffer must only be partially flushed from the end of the last
  37    flush until the current position in the record. */
  38
  39 struct fbuf
  40 {
  41   char *buf;                    /* Start of buffer.  */
  42   size_t len;                   /* Length of buffer.  */
  43   size_t act;                   /* Active bytes in buffer.  */
  44   size_t pos;                   /* Current position in buffer.  */
  45 };
  46
  47 extern void fbuf_init (gfc_unit *, size_t);
  48 internal_proto(fbuf_init);
  49
  50 extern void fbuf_destroy (gfc_unit *);
  51 internal_proto(fbuf_destroy);
  52
  53 extern ptrdiff_t fbuf_reset (gfc_unit *);
  54 internal_proto(fbuf_reset);
  55
  56 extern char *fbuf_alloc (gfc_unit *, size_t);
  57 internal_proto(fbuf_alloc);
  58
  59 extern int fbuf_flush (gfc_unit *, unit_mode);
  60 internal_proto(fbuf_flush);
  61
  62 extern int fbuf_flush_list (gfc_unit *, unit_mode);
  63 internal_proto(fbuf_flush_list);
  64
  65 extern ptrdiff_t fbuf_seek (gfc_unit *, ptrdiff_t, int);
  66 internal_proto(fbuf_seek);
  67
  68 extern char *fbuf_read (gfc_unit *, size_t *);
  69 internal_proto(fbuf_read);
  70
  71 /* Never call this function, only use fbuf_getc().  */
  72 extern int fbuf_getc_refill (gfc_unit *);
  73 internal_proto(fbuf_getc_refill);
  74
  75 static inline int
  76 fbuf_getc (gfc_unit *u)
  77 {
  78   if (u->fbuf->pos < u->fbuf->act)
  79     return (unsigned char) u->fbuf->buf[u->fbuf->pos++];
  80   return fbuf_getc_refill (u);
  81 }
  82
  83 static inline char *
  84 fbuf_getptr (gfc_unit *u)
  85 {
  86   return (char*) (u->fbuf->buf + u->fbuf->pos);
  87 }
  88
  89 #endif