1  /* FILE * interface to a struct __wprintf_buffer.  Wide version.
       2     Copyright (C) 2022-2023 Free Software Foundation, Inc.
       3     This file is part of the GNU C Library.
       4  
       5     The GNU C Library is free software; you can redistribute it and/or
       6     modify it under the terms of the GNU Lesser General Public
       7     License as published by the Free Software Foundation; either
       8     version 2.1 of the License, or (at your option) any later version.
       9  
      10     The GNU C Library is distributed in the hope that it will be useful,
      11     but WITHOUT ANY WARRANTY; without even the implied warranty of
      12     MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
      13     Lesser General Public License for more details.
      14  
      15     You should have received a copy of the GNU Lesser General Public
      16     License along with the GNU C Library; if not, see
      17     <https://www.gnu.org/licenses/>.  */
      18  
      19  #include <printf_buffer_as_file.h>
      20  
      21  #include <assert.h>
      22  #include <printf_buffer.h>
      23  
      24  /* Commit the data directly written through the stdio stream.  */
      25  static void
      26  __wprintf_buffer_as_file_commit (struct __wprintf_buffer_as_file *file)
      27  {
      28    /* Check that the write pointers in the file stream are consistent
      29       with the next buffer.  */
      30    assert (file->wide_stream._IO_write_ptr >= file->next->write_ptr);
      31    assert (file->wide_stream._IO_write_ptr <= file->next->write_end);
      32    assert (file->wide_stream._IO_write_base == file->next->write_base);
      33    assert (file->wide_stream._IO_write_end == file->next->write_end);
      34  
      35    file->next->write_ptr = file->wide_stream._IO_write_ptr;
      36  }
      37  
      38  /* Pointer the FILE * write buffer into the active struct __wprintf_buffer
      39     area.  */
      40  static void
      41  __wprintf_buffer_as_file_switch_to_buffer (struct __wprintf_buffer_as_file *file)
      42  {
      43    file->wide_stream._IO_write_base = file->next->write_base;
      44    file->wide_stream._IO_write_ptr = file->next->write_ptr;
      45    file->wide_stream._IO_write_end = file->next->write_end;
      46  }
      47  
      48  /* Only a small subset of the vtable functions is implemented here,
      49     following _IO_obstack_jumps.  */
      50  
      51  wint_t
      52  __wprintf_buffer_as_file_overflow (FILE *fp, int ch)
      53  {
      54    struct __wprintf_buffer_as_file *file
      55      = (struct __wprintf_buffer_as_file *) fp;
      56  
      57    __wprintf_buffer_as_file_commit (file);
      58  
      59    /* EOF means only a flush is requested.   */
      60    if (ch != WEOF)
      61      __wprintf_buffer_putc (file->next, ch);
      62    else
      63      ch = 0;
      64  
      65    /* Ensure that flushing actually produces room.  */
      66    if (!__wprintf_buffer_has_failed (file->next)
      67        && file->next->write_ptr == file->next->write_end)
      68      __wprintf_buffer_flush (file->next);
      69  
      70    __wprintf_buffer_as_file_switch_to_buffer (file);
      71  
      72    if (!__wprintf_buffer_has_failed (file->next))
      73      return (unsigned char) ch;
      74    else
      75      return WEOF;
      76  }
      77  
      78  size_t
      79  __wprintf_buffer_as_file_xsputn (FILE *fp, const void *buf, size_t len)
      80  {
      81    struct __wprintf_buffer_as_file *file
      82      = (struct __wprintf_buffer_as_file *) fp;
      83  
      84    __wprintf_buffer_as_file_commit (file);
      85  
      86    /* Copy the data.  */
      87    __wprintf_buffer_write (file->next, buf, len);
      88  
      89    __wprintf_buffer_as_file_switch_to_buffer (file);
      90  
      91    if (!__wprintf_buffer_has_failed (file->next))
      92      return len;
      93    else
      94      /* We may actually have written something.  But the stream is
      95         corrupted in this case anyway, so try not to divine the write
      96         count here.  */
      97      return 0;
      98  }
      99  
     100  void
     101  __wprintf_buffer_as_file_init (struct __wprintf_buffer_as_file *file,
     102                                 struct __wprintf_buffer *next)
     103  {
     104    file->stream._lock = NULL;
     105    _IO_no_init (&file->stream, _IO_USER_LOCK, 0, &file->wide_stream,
     106                 &_IO_wprintf_buffer_as_file_jumps);
     107    _IO_fwide (&file->stream, 1);
     108  
     109    /* Set up the write buffer from the next buffer.  */
     110    file->next = next;
     111    __wprintf_buffer_as_file_switch_to_buffer (file);
     112  
     113    /* Mark the read area as inactive, by making all pointers equal.  */
     114    file->stream._IO_read_base = file->stream._IO_write_base;
     115    file->stream._IO_read_ptr = file->stream._IO_write_base;
     116    file->stream._IO_read_end = file->stream._IO_write_base;
     117  }
     118  
     119  bool
     120  __wprintf_buffer_as_file_terminate (struct __wprintf_buffer_as_file *file)
     121  {
     122    if (file->stream._flags & _IO_ERR_SEEN)
     123      return false;
     124    else
     125      {
     126        __wprintf_buffer_as_file_commit (file);
     127        return true;
     128      }
     129  }