1  /* FILE * interface to a struct __*printf_buffer.
       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  /* Registered printf format specifier callbacks produce data via a
      20     FILE * stream.  struct __printf_buffer_as_file enables vfprintf to
      21     create a suitable stdio stream.  Likewise struct
      22     __wprintf_buffer_as_file for vfwprintf.  */
      23  
      24  #ifndef PRINTF_BUFFER_AS_FILE_H
      25  #define PRINTF_BUFFER_AS_FILE_H
      26  
      27  #include <libio/libioP.h>
      28  
      29  struct __printf_buffer;
      30  
      31  struct __printf_buffer_as_file
      32  {
      33    /* Interface to libio.  */
      34    FILE stream;
      35    const struct _IO_jump_t *vtable;
      36  
      37    /* Pointer to the underlying buffer.  */
      38    struct __printf_buffer *next;
      39  };
      40  
      41  /* Initialization *FP so that data written to its FILE * stream ends
      42     up in NEXT.  */
      43  void __printf_buffer_as_file_init (struct __printf_buffer_as_file *fp,
      44                                     struct __printf_buffer *next)
      45    attribute_hidden;
      46  
      47  /* Returns the FILE * that can be used to write data to the
      48     buffer.  */
      49  static inline FILE *
      50  __printf_buffer_as_file_get (struct __printf_buffer_as_file *file)
      51  {
      52    return &file->stream;
      53  }
      54  
      55  /* Transfers all pending data from the FILE * to the underlying
      56     buffer.  Returns true if there have been no errors.  */
      57  bool __printf_buffer_as_file_terminate (struct __printf_buffer_as_file *)
      58    attribute_hidden;
      59  
      60  /* Wide variant follows.  */
      61  
      62  struct __wprintf_buffer;
      63  struct __wprintf_buffer_as_file
      64  {
      65    /* Interface to libio.  */
      66    FILE stream;
      67    const struct _IO_jump_t *vtable;
      68    struct _IO_wide_data wide_stream;
      69  
      70    /* Pointer to the underlying buffer.  */
      71    struct __wprintf_buffer *next;
      72  };
      73  
      74  void __wprintf_buffer_as_file_init (struct __wprintf_buffer_as_file *fp,
      75                                      struct __wprintf_buffer *next)
      76    attribute_hidden;
      77  
      78  static inline FILE *
      79  __wprintf_buffer_as_file_get (struct __wprintf_buffer_as_file *file)
      80  {
      81    return &file->stream;
      82  }
      83  
      84  bool __wprintf_buffer_as_file_terminate (struct __wprintf_buffer_as_file *)
      85    attribute_hidden;
      86  
      87  #endif /* PRINTF_BUFFER_AS_FILE_H */