libio/memstream.c

   1 /* Copyright (C) 1995-97,99,2000,2002,2003,2004 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 Lesser General Public
   6    License as published by the Free Software Foundation; either
   7    version 2.1 of the 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    Lesser General Public License for more details.
  13
  14    You should have received a copy of the GNU Lesser General Public
  15    License along with the GNU C Library; if not, write to the Free
  16    Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
  17    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 (_IO_FILE* fp) __THROW;
  34 static void _IO_mem_finish (_IO_FILE* fp, int) __THROW;
  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, INTUSE(_IO_str_overflow)),
  42   JUMP_INIT (underflow, INTUSE(_IO_str_underflow)),
  43   JUMP_INIT (uflow, INTUSE(_IO_default_uflow)),
  44   JUMP_INIT (pbackfail, INTUSE(_IO_str_pbackfail)),
  45   JUMP_INIT (xsputn, INTUSE(_IO_default_xsputn)),
  46   JUMP_INIT (xsgetn, INTUSE(_IO_default_xsgetn)),
  47   JUMP_INIT (seekoff, INTUSE(_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, INTUSE(_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     struct _IO_wide_data wd;
  76   } *new_f;
  77   char *buf;
  78
  79   new_f = (struct locked_FILE *) malloc (sizeof (struct locked_FILE));
  80   if (new_f == NULL)
  81     return NULL;
  82 #ifdef _IO_MTSAFE_IO
  83   new_f->fp._sf._sbf._f._lock = &new_f->lock;
  84 #endif
  85
  86   buf = malloc (_IO_BUFSIZ);
  87   if (buf == NULL)
  88     return NULL;
  89   INTUSE(_IO_init) (&new_f->fp._sf._sbf._f, 0);
  90   _IO_JUMPS ((struct _IO_FILE_plus *) &new_f->fp._sf._sbf) = &_IO_mem_jumps;
  91   _IO_str_init_static_internal (&new_f->fp._sf, buf, _IO_BUFSIZ, buf);
  92   new_f->fp._sf._sbf._f._flags &= ~_IO_USER_BUF;
  93   new_f->fp._sf._s._allocate_buffer = (_IO_alloc_type) malloc;
  94   new_f->fp._sf._s._free_buffer = (_IO_free_type) free;
  95
  96   new_f->fp.bufloc = bufloc;
  97   new_f->fp.sizeloc = sizeloc;
  98
  99   return (_IO_FILE *) &new_f->fp._sf._sbf;
 100 }
 101 libc_hidden_def (open_memstream)
 102
 103
 104 static int
 105 _IO_mem_sync (fp)
 106      _IO_FILE* fp;
 107 {
 108   struct _IO_FILE_memstream *mp = (struct _IO_FILE_memstream *) fp;
 109   int res;
 110
 111   res = _IO_default_sync (fp);
 112   if (res < 0)
 113     return res;
 114
 115   if (fp->_IO_write_ptr == fp->_IO_write_end)
 116     {
 117       INTUSE(_IO_str_overflow) (fp, '\0');
 118       --fp->_IO_write_ptr;
 119     }
 120   else
 121     *fp->_IO_write_ptr = '\0';
 122
 123   *mp->bufloc = fp->_IO_write_base;
 124   *mp->sizeloc = fp->_IO_write_ptr - fp->_IO_write_base;
 125
 126   return 0;
 127 }
 128
 129
 130 static void
 131 _IO_mem_finish (fp, dummy)
 132      _IO_FILE* fp;
 133      int dummy;
 134 {
 135   struct _IO_FILE_memstream *mp = (struct _IO_FILE_memstream *) fp;
 136
 137   *mp->bufloc = (char *) realloc (fp->_IO_write_base,
 138                                   fp->_IO_write_ptr - fp->_IO_write_base + 1);
 139   if (*mp->bufloc != NULL)
 140     {
 141       (*mp->bufloc)[fp->_IO_write_ptr - fp->_IO_write_base] = '\0';
 142       *mp->sizeloc = fp->_IO_write_ptr - fp->_IO_write_base;
 143     }
 144
 145   fp->_IO_buf_base = NULL;
 146
 147   INTUSE(_IO_default_finish) (fp, 0);
 148 }