libio/memstream.c

   1 /* Copyright (C) 1995 Free Software Foundation, Inc.
   2 This file is part of the GNU C Library.
   3
   4 The GNU C Library is free software; you can redistribute it and/or
   5 modify it under the terms of the GNU Library General Public License as
   6 published by the Free Software Foundation; either version 2 of the
   7 License, or (at your option) any later version.
   8
   9 The GNU C Library is distributed in the hope that it will be useful,
  10 but WITHOUT ANY WARRANTY; without even the implied warranty of
  11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
  12 Library General Public License for more details.
  13
  14 You should have received a copy of the GNU Library General Public
  15 License along with the GNU C Library; see the file COPYING.LIB.  If
  16 not, write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17 Boston, MA 02111-1307, USA.  */
  18
  19 #include "strfile.h"
  20 #include "libioP.h"
  21 #include <stdlib.h>
  22
  23
  24 struct _IO_FILE_memstream
  25 {
  26   _IO_strfile _sf;
  27   char **bufloc;
  28   _IO_size_t *sizeloc;
  29 };
  30
  31
  32 static int _IO_mem_sync __P ((_IO_FILE* fp));
  33 static void _IO_mem_finish __P ((_IO_FILE* fp));
  34
  35
  36 static const struct _IO_jump_t _IO_mem_jumps =
  37 {
  38   JUMP_INIT_DUMMY,
  39   JUMP_INIT (finish, _IO_mem_finish),
  40   JUMP_INIT (overflow, _IO_str_overflow),
  41   JUMP_INIT (underflow, _IO_str_underflow),
  42   JUMP_INIT (uflow, _IO_default_uflow),
  43   JUMP_INIT (pbackfail, _IO_str_pbackfail),
  44   JUMP_INIT (xsputn, _IO_default_xsputn),
  45   JUMP_INIT (xsgetn, _IO_default_xsgetn),
  46   JUMP_INIT (seekoff, _IO_str_seekoff),
  47   JUMP_INIT (seekpos, _IO_default_seekpos),
  48   JUMP_INIT (setbuf, _IO_default_setbuf),
  49   JUMP_INIT (sync, _IO_mem_sync),
  50   JUMP_INIT (doallocate, _IO_default_doallocate),
  51   JUMP_INIT (read, _IO_default_read),
  52   JUMP_INIT (write, _IO_default_write),
  53   JUMP_INIT (seek, _IO_default_seek),
  54   JUMP_INIT (close, _IO_default_close),
  55   JUMP_INIT (stat, _IO_default_stat)
  56 };
  57
  58 /* Open a stream that writes into a malloc'd buffer that is expanded as
  59    necessary.  *BUFLOC and *SIZELOC are updated with the buffer's location
  60    and the number of characters written on fflush or fclose.  */
  61 _IO_FILE *
  62 open_memstream (bufloc, sizeloc)
  63      char **bufloc;
  64      _IO_size_t *sizeloc;
  65 {
  66   struct _IO_FILE_memstream *fp;
  67   char *buf;
  68
  69   fp = (struct _IO_FILE_memstream *)
  70     malloc (sizeof (struct _IO_FILE_memstream));
  71   if (fp == NULL)
  72     return NULL;
  73
  74   buf = ALLOC_BUF (_IO_BUFSIZ);
  75   _IO_init (&fp->_sf._f, 0);
  76   _IO_JUMPS (&fp->_sf._f) = &_IO_mem_jumps;
  77   _IO_str_init_static (&fp->_sf._f, buf, _IO_BUFSIZ, buf);
  78   fp->_sf._f._flags &= ~_IO_USER_BUF;
  79   fp->_sf._s._allocate_buffer = (_IO_alloc_type) malloc;
  80   fp->_sf._s._free_buffer = (_IO_free_type) free;
  81
  82   fp->bufloc = bufloc;
  83   fp->sizeloc = sizeloc;
  84
  85   return &fp->_sf._f;
  86 }
  87
  88
  89 static int
  90 _IO_mem_sync (fp)
  91      _IO_FILE* fp;
  92 {
  93   struct _IO_FILE_memstream *mp = (struct _IO_FILE_memstream *) fp;
  94   int res;
  95
  96   res = _IO_default_sync (fp);
  97   if (res < 0)
  98     return res;
  99
 100   if (fp->_IO_write_ptr == fp->_IO_write_end)
 101     {
 102       _IO_str_overflow (fp, '\0');
 103       --fp->_IO_write_ptr;
 104     }
 105   else
 106     *fp->_IO_write_ptr = '\0';
 107
 108   *mp->bufloc = fp->_IO_write_base;
 109   *mp->sizeloc = fp->_IO_write_ptr - fp->_IO_write_base;
 110
 111   return 0;
 112 }
 113
 114
 115 static void
 116 _IO_mem_finish (fp)
 117      _IO_FILE* fp;
 118 {
 119   struct _IO_FILE_memstream *mp = (struct _IO_FILE_memstream *) fp;
 120
 121   *mp->bufloc = (char *) realloc (fp->_IO_write_base,
 122                                   fp->_IO_write_ptr - fp->_IO_write_base + 1);
 123   if (*mp->bufloc != NULL)
 124     {
 125       (*mp->bufloc)[fp->_IO_write_ptr - fp->_IO_write_base] = '\0';
 126       *mp->sizeloc = fp->_IO_write_ptr - fp->_IO_write_base;
 127     }
 128
 129   fp->_IO_buf_base = NULL;
 130
 131   _IO_default_finish (fp);
 132 }