stdio-common/printf_buffer_as_file.h

   1 /* FILE * interface to a struct __*printf_buffer.
   2    Copyright (C) 2022-2024 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 */