libio/memstream.c

   1 /* Copyright (C) 1995, 1996, 1997 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 not,
  16    write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
  17    Boston, MA 02111-1307, USA.  */
  18
  19 #include "libioP.h"
  20 #include "strfile.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, int));
  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   JUMP_INIT(showmanyc, _IO_default_showmanyc),
  58   JUMP_INIT(imbue, _IO_default_imbue)
  59 };
  60
  61 /* Open a stream that writes into a malloc'd buffer that is expanded as
  62    necessary.  *BUFLOC and *SIZELOC are updated with the buffer's location
  63    and the number of characters written on fflush or fclose.  */
  64 _IO_FILE *
  65 open_memstream (bufloc, sizeloc)
  66      char **bufloc;
  67      _IO_size_t *sizeloc;
  68 {
  69   struct locked_FILE
  70   {
  71     struct _IO_FILE_memstream fp;
  72 #ifdef _IO_MTSAFE_IO
  73     _IO_lock_t lock;
  74 #endif
  75   } *new_f;
  76   char *buf;
  77
  78   new_f = (struct locked_FILE *) malloc (sizeof (struct locked_FILE));
  79   if (new_f == NULL)
  80     return NULL;
  81 #ifdef _IO_MTSAFE_IO
  82   new_f->fp._sf._sbf._f._lock = &new_f->lock;
  83 #endif
  84
  85   buf = malloc (_IO_BUFSIZ);
  86   if (buf == NULL)
  87     return NULL;
  88   _IO_init (&new_f->fp._sf._sbf._f, 0);
  89   _IO_JUMPS (&new_f->fp._sf._sbf._f) = &_IO_mem_jumps;
  90   _IO_str_init_static (&new_f->fp._sf._sbf._f, buf, _IO_BUFSIZ, buf);
  91   new_f->fp._sf._sbf._f._flags &= ~_IO_USER_BUF;
  92   new_f->fp._sf._s._allocate_buffer = (_IO_alloc_type) malloc;
  93   new_f->fp._sf._s._free_buffer = (_IO_free_type) free;
  94
  95   new_f->fp.bufloc = bufloc;
  96   new_f->fp.sizeloc = sizeloc;
  97
  98   return &new_f->fp._sf._sbf._f;
  99 }
 100
 101
 102 static int
 103 _IO_mem_sync (fp)
 104      _IO_FILE* fp;
 105 {
 106   struct _IO_FILE_memstream *mp = (struct _IO_FILE_memstream *) fp;
 107   int res;
 108
 109   res = _IO_default_sync (fp);
 110   if (res < 0)
 111     return res;
 112
 113   if (fp->_IO_write_ptr == fp->_IO_write_end)
 114     {
 115       _IO_str_overflow (fp, '\0');
 116       --fp->_IO_write_ptr;
 117     }
 118   else
 119     *fp->_IO_write_ptr = '\0';
 120
 121   *mp->bufloc = fp->_IO_write_base;
 122   *mp->sizeloc = fp->_IO_write_ptr - fp->_IO_write_base;
 123
 124   return 0;
 125 }
 126
 127
 128 static void
 129 _IO_mem_finish (fp, dummy)
 130      _IO_FILE* fp;
 131      int dummy;
 132 {
 133   struct _IO_FILE_memstream *mp = (struct _IO_FILE_memstream *) fp;
 134
 135   *mp->bufloc = (char *) realloc (fp->_IO_write_base,
 136                                   fp->_IO_write_ptr - fp->_IO_write_base + 1);
 137   if (*mp->bufloc != NULL)
 138     {
 139       (*mp->bufloc)[fp->_IO_write_ptr - fp->_IO_write_base] = '\0';
 140       *mp->sizeloc = fp->_IO_write_ptr - fp->_IO_write_base;
 141     }
 142
 143   fp->_IO_buf_base = NULL;
 144
 145   _IO_default_finish (fp, 0);
 146 }