glibc/libio/obprintf.c

/* Print output of stream to given obstack.
   Copyright (C) 1996-2021 Free Software Foundation, Inc.
   This file is part of the GNU C Library.

   The GNU C Library is free software; you can redistribute it and/or
   modify it under the terms of the GNU Lesser General Public
   License as published by the Free Software Foundation; either
   version 2.1 of the License, or (at your option) any later version.

   The GNU C Library is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
   Lesser General Public License for more details.

   You should have received a copy of the GNU Lesser General Public
   License along with the GNU C Library; if not, see
   <https://www.gnu.org/licenses/>.  */


#include <stdlib.h>
#include "libioP.h"
#include "strfile.h"
#include <assert.h>
#include <string.h>
#include <errno.h>
#include <obstack.h>
#include <stdarg.h>
#include <stdio_ext.h>


struct _IO_obstack_file
{
  struct _IO_FILE_plus file;
  struct obstack *obstack;
};


static int
_IO_obstack_overflow (FILE *fp, int c)
{
  struct obstack *obstack = ((struct _IO_obstack_file *) fp)->obstack;
  int size;

  /* Make room for another character.  This might as well allocate a
     new chunk a memory and moves the old contents over.  */
  assert (c != EOF);
  obstack_1grow (obstack, c);

  /* Setup the buffer pointers again.  */
  fp->_IO_write_base = obstack_base (obstack);
  fp->_IO_write_ptr = obstack_next_free (obstack);
  size = obstack_room (obstack);
  fp->_IO_write_end = fp->_IO_write_ptr + size;
  /* Now allocate the rest of the current chunk.  */
  obstack_blank_fast (obstack, size);

  return c;
}


static size_t
_IO_obstack_xsputn (FILE *fp, const void *data, size_t n)
{
  struct obstack *obstack = ((struct _IO_obstack_file *) fp)->obstack;

  if (fp->_IO_write_ptr + n > fp->_IO_write_end)
    {
      int size;

      /* We need some more memory.  First shrink the buffer to the
	 space we really currently need.  */
      obstack_blank_fast (obstack, fp->_IO_write_ptr - fp->_IO_write_end);

      /* Now grow for N bytes, and put the data there.  */
      obstack_grow (obstack, data, n);

      /* Setup the buffer pointers again.  */
      fp->_IO_write_base = obstack_base (obstack);
      fp->_IO_write_ptr = obstack_next_free (obstack);
      size = obstack_room (obstack);
      fp->_IO_write_end = fp->_IO_write_ptr + size;
      /* Now allocate the rest of the current chunk.  */
      obstack_blank_fast (obstack, size);
    }
  else
    fp->_IO_write_ptr = __mempcpy (fp->_IO_write_ptr, data, n);

  return n;
}


/* the jump table.  */
const struct _IO_jump_t _IO_obstack_jumps libio_vtable attribute_hidden =
{
  JUMP_INIT_DUMMY,
  JUMP_INIT(finish, NULL),
  JUMP_INIT(overflow, _IO_obstack_overflow),
  JUMP_INIT(underflow, NULL),
  JUMP_INIT(uflow, NULL),
  JUMP_INIT(pbackfail, NULL),
  JUMP_INIT(xsputn, _IO_obstack_xsputn),
  JUMP_INIT(xsgetn, NULL),
  JUMP_INIT(seekoff, NULL),
  JUMP_INIT(seekpos, NULL),
  JUMP_INIT(setbuf, NULL),
  JUMP_INIT(sync, NULL),
  JUMP_INIT(doallocate, NULL),
  JUMP_INIT(read, NULL),
  JUMP_INIT(write, NULL),
  JUMP_INIT(seek, NULL),
  JUMP_INIT(close, NULL),
  JUMP_INIT(stat, NULL),
  JUMP_INIT(showmanyc, NULL),
  JUMP_INIT(imbue, NULL)
};


int
__obstack_vprintf_internal (struct obstack *obstack, const char *format,
			    va_list args, unsigned int mode_flags)
{
  struct obstack_FILE
    {
      struct _IO_obstack_file ofile;
  } new_f;
  int result;
  int size;
  int room;

#ifdef _IO_MTSAFE_IO
  new_f.ofile.file.file._lock = NULL;
#endif

  _IO_no_init (&new_f.ofile.file.file, _IO_USER_LOCK, -1, NULL, NULL);
  _IO_JUMPS (&new_f.ofile.file) = &_IO_obstack_jumps;
  room = obstack_room (obstack);
  size = obstack_object_size (obstack) + room;
  if (size == 0)
    {
      /* We have to handle the allocation a bit different since the
	 `_IO_str_init_static' function would handle a size of zero
	 different from what we expect.  */

      /* Get more memory.  */
      obstack_make_room (obstack, 64);

      /* Recompute how much room we have.  */
      room = obstack_room (obstack);
      size = room;

      assert (size != 0);
    }

  _IO_str_init_static_internal ((struct _IO_strfile_ *) &new_f.ofile,
				obstack_base (obstack),
				size, obstack_next_free (obstack));
  /* Now allocate the rest of the current chunk.  */
  assert (size == (new_f.ofile.file.file._IO_write_end
		   - new_f.ofile.file.file._IO_write_base));
  assert (new_f.ofile.file.file._IO_write_ptr
	  == (new_f.ofile.file.file._IO_write_base
	      + obstack_object_size (obstack)));
  obstack_blank_fast (obstack, room);

  new_f.ofile.obstack = obstack;

  result = __vfprintf_internal (&new_f.ofile.file.file, format, args,
				mode_flags);

  /* Shrink the buffer to the space we really currently need.  */
  obstack_blank_fast (obstack, (new_f.ofile.file.file._IO_write_ptr
				- new_f.ofile.file.file._IO_write_end));

  return result;
}

int
__obstack_vprintf (struct obstack *obstack, const char *format, va_list ap)
{
  return __obstack_vprintf_internal (obstack, format, ap, 0);
}
ldbl_weak_alias (__obstack_vprintf, obstack_vprintf)

int
__obstack_printf (struct obstack *obstack, const char *format, ...)
{
  int result;
  va_list ap;
  va_start (ap, format);
  result = __obstack_vprintf_internal (obstack, format, ap, 0);
  va_end (ap);
  return result;
}
ldbl_weak_alias (__obstack_printf, obstack_printf)