libio/memstream.c

   1 /* Copyright (C) 1995, 1996 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 <stdio.h>
  22 #include <stdlib.h>
  23
  24
  25 struct _IO_FILE_memstream
  26 {
  27   _IO_strfile _sf;
  28   char **bufloc;
  29   _IO_size_t *sizeloc;
  30 };
  31
  32
  33 static int _IO_mem_sync __P ((_IO_FILE* fp));
  34 static void _IO_mem_finish __P ((_IO_FILE* fp));
  35
  36
  37 static const struct _IO_jump_t _IO_mem_jumps =
  38 {
  39   JUMP_INIT_DUMMY,
  40   JUMP_INIT (finish, _IO_mem_finish),
  41   JUMP_INIT (overflow, _IO_str_overflow),
  42   JUMP_INIT (underflow, _IO_str_underflow),
  43   JUMP_INIT (uflow, _IO_default_uflow),
  44   JUMP_INIT (pbackfail, _IO_str_pbackfail),
  45   JUMP_INIT (xsputn, _IO_default_xsputn),
  46   JUMP_INIT (xsgetn, _IO_default_xsgetn),
  47   JUMP_INIT (seekoff, _IO_str_seekoff),
  48   JUMP_INIT (seekpos, _IO_default_seekpos),
  49   JUMP_INIT (setbuf, _IO_default_setbuf),
  50   JUMP_INIT (sync, _IO_mem_sync),
  51   JUMP_INIT (doallocate, _IO_default_doallocate),
  52   JUMP_INIT (read, _IO_default_read),
  53   JUMP_INIT (write, _IO_default_write),
  54   JUMP_INIT (seek, _IO_default_seek),
  55   JUMP_INIT (close, _IO_default_close),
  56   JUMP_INIT (stat, _IO_default_stat)
  57 };
  58
  59 /* Open a stream that writes into a malloc'd buffer that is expanded as
  60    necessary.  *BUFLOC and *SIZELOC are updated with the buffer's location
  61    and the number of characters written on fflush or fclose.  */
  62 _IO_FILE *
  63 open_memstream (bufloc, sizeloc)
  64      char **bufloc;
  65      _IO_size_t *sizeloc;
  66 {
  67   struct _IO_FILE_memstream *fp;
  68   char *buf;
  69
  70   fp = (struct _IO_FILE_memstream *)
  71     malloc (sizeof (struct _IO_FILE_memstream));
  72   if (fp == NULL)
  73     return NULL;
  74
  75   buf = ALLOC_BUF (_IO_BUFSIZ);
  76   _IO_init (&fp->_sf._f, 0);
  77   _IO_JUMPS (&fp->_sf._f) = &_IO_mem_jumps;
  78   _IO_str_init_static (&fp->_sf._f, buf, _IO_BUFSIZ, buf);
  79   fp->_sf._f._flags &= ~_IO_USER_BUF;
  80   fp->_sf._s._allocate_buffer = (_IO_alloc_type) malloc;
  81   fp->_sf._s._free_buffer = (_IO_free_type) free;
  82
  83   fp->bufloc = bufloc;
  84   fp->sizeloc = sizeloc;
  85
  86   return &fp->_sf._f;
  87 }
  88
  89
  90 static int
  91 _IO_mem_sync (fp)
  92      _IO_FILE* fp;
  93 {
  94   struct _IO_FILE_memstream *mp = (struct _IO_FILE_memstream *) fp;
  95   int res;
  96
  97   res = _IO_default_sync (fp);
  98   if (res < 0)
  99     return res;
 100
 101   if (fp->_IO_write_ptr == fp->_IO_write_end)
 102     {
 103       _IO_str_overflow (fp, '\0');
 104       --fp->_IO_write_ptr;
 105     }
 106   else
 107     *fp->_IO_write_ptr = '\0';
 108
 109   *mp->bufloc = fp->_IO_write_base;
 110   *mp->sizeloc = fp->_IO_write_ptr - fp->_IO_write_base;
 111
 112   return 0;
 113 }
 114
 115
 116 static void
 117 _IO_mem_finish (fp)
 118      _IO_FILE* fp;
 119 {
 120   struct _IO_FILE_memstream *mp = (struct _IO_FILE_memstream *) fp;
 121
 122   *mp->bufloc = (char *) realloc (fp->_IO_write_base,
 123                                   fp->_IO_write_ptr - fp->_IO_write_base + 1);
 124   if (*mp->bufloc != NULL)
 125     {
 126       (*mp->bufloc)[fp->_IO_write_ptr - fp->_IO_write_base] = '\0';
 127       *mp->sizeloc = fp->_IO_write_ptr - fp->_IO_write_base;
 128     }
 129
 130   fp->_IO_buf_base = NULL;
 131
 132   _IO_default_finish (fp);
 133 }