libgfortran/io/fbuf.c

   1 /* Copyright (C) 2008 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 2, or (at your option)
   9 any later version.
  10
  11 In addition to the permissions in the GNU General Public License, the
  12 Free Software Foundation gives you unlimited permission to link the
  13 compiled version of this file into combinations with other programs,
  14 and to distribute those combinations without any restriction coming
  15 from the use of this file.  (The General Public License restrictions
  16 do apply in other respects; for example, they cover modification of
  17 the file, and distribution when not linked into a combine
  18 executable.)
  19
  20 Libgfortran is distributed in the hope that it will be useful,
  21 but WITHOUT ANY WARRANTY; without even the implied warranty of
  22 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  23 GNU General Public License for more details.
  24
  25 You should have received a copy of the GNU General Public License
  26 along with Libgfortran; see the file COPYING.  If not, write to
  27 the Free Software Foundation, 51 Franklin Street, Fifth Floor,
  28 Boston, MA 02110-1301, USA.  */
  29
  30
  31 #include "io.h"
  32 #include <string.h>
  33 #include <stdlib.h>
  34
  35
  36 void
  37 fbuf_init (gfc_unit * u, size_t len)
  38 {
  39   if (len == 0)
  40     len = 4096;                 /* Default size one page.  */
  41
  42   u->fbuf = get_mem (sizeof (fbuf));
  43   u->fbuf->buf = u->fbuf->ptr = get_mem (len);
  44   u->fbuf->len = len;
  45   u->fbuf->act = u->fbuf->flushed = 0;
  46 }
  47
  48
  49 void
  50 fbuf_reset (gfc_unit * u)
  51 {
  52   u->fbuf->act = u->fbuf->flushed = 0;
  53   u->fbuf->ptr = u->fbuf->buf;
  54 }
  55
  56
  57 void
  58 fbuf_destroy (gfc_unit * u)
  59 {
  60   if (u->fbuf == NULL)
  61     return;
  62   if (u->fbuf->buf)
  63     free_mem (u->fbuf->buf);
  64   free_mem (u->fbuf);
  65 }
  66
  67
  68 /* Return a pointer to the current position in the buffer, and increase
  69    the pointer by len. Makes sure that the buffer is big enough,
  70    reallocating if necessary.  */
  71
  72 char *
  73 fbuf_alloc (gfc_unit * u, size_t len)
  74 {
  75   size_t newlen, ptrpos;
  76   char *dest;
  77   if (u->fbuf->ptr + len > u->fbuf->buf + u->fbuf->len)
  78     {
  79       /* Round up to nearest multiple of the current buffer length.  */
  80       ptrpos = u->fbuf->ptr - u->fbuf->buf;
  81       newlen = ((ptrpos + len) / u->fbuf->len + 1) * u->fbuf->len;
  82       dest = realloc (u->fbuf->buf, newlen);
  83       if (dest == NULL)
  84         return NULL;
  85       u->fbuf->buf = dest;
  86       u->fbuf->ptr = dest + ptrpos;
  87       u->fbuf->len = newlen;
  88     }
  89   dest = u->fbuf->ptr;
  90   u->fbuf->ptr += len;
  91   if ((size_t) (u->fbuf->ptr - u->fbuf->buf) > u->fbuf->act)
  92     u->fbuf->act = u->fbuf->ptr - u->fbuf->buf;
  93   return dest;
  94 }
  95
  96
  97 int
  98 fbuf_flush (gfc_unit * u, int record_done)
  99 {
 100   int status;
 101   size_t nbytes;
 102
 103   if (!u->fbuf)
 104     return 0;
 105   if (u->fbuf->act - u->fbuf->flushed != 0)
 106     {
 107       if (record_done)
 108         nbytes = u->fbuf->act - u->fbuf->flushed;
 109       else
 110         nbytes = u->fbuf->ptr - u->fbuf->buf - u->fbuf->flushed;
 111       status = swrite (u->s, u->fbuf->buf + u->fbuf->flushed, &nbytes);
 112       u->fbuf->flushed += nbytes;
 113     }
 114   else
 115     status = 0;
 116   if (record_done)
 117     fbuf_reset (u);
 118   return status;
 119 }
 120
 121
 122 int
 123 fbuf_seek (gfc_unit * u, gfc_offset off)
 124 {
 125   gfc_offset pos = u->fbuf->ptr - u->fbuf->buf + off;
 126   if (pos < 0)
 127     return -1;
 128   u->fbuf->ptr = u->fbuf->buf + pos;
 129   if (pos > u->fbuf->act)
 130     u->fbuf->act = pos;
 131   return 0;
 132 }