stdio/linewrap.h

   1 /* Word-wrapping and line-truncating streams.
   2 Copyright (C) 1996 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 Library General Public License as
   7 published by the Free Software Foundation; either version 2 of the
   8 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 Library General Public License for more details.
  14
  15 You should have received a copy of the GNU Library General Public
  16 License along with the GNU C Library; see the file COPYING.LIB.  If
  17 not, write to the Free Software Foundation, Inc., 675 Mass Ave,
  18 Cambridge, MA 02139, USA.  */
  19
  20 #ifndef __LINEWRAP_H__
  21 #define __LINEWRAP_H__
  22
  23 #include <stdio.h>
  24 #include <ctype.h>
  25 #include <string.h>
  26
  27 #include <features.h>
  28
  29 #include <string.h>             /* Need size_t.  */
  30
  31 __BEGIN_DECLS
  32
  33 /* We keep this data for each line-wrapping stream.  */
  34 struct line_wrap_data
  35   {
  36     size_t lmargin, rmargin;    /* Left and right margins.  */
  37     size_t wmargin;             /* Margin to wrap to, or -1 to truncate.  */
  38     size_t point;               /* Current column of last chars flushed.  */
  39
  40     /* Original cookie and hooks from the stream.  */
  41     void *cookie;
  42     void (*output) (FILE *, int);
  43     __io_close_fn *close;
  44     __io_fileno_fn *fileno;
  45     __io_seek_fn *seek;
  46   };
  47 \f
  48 /* Modify STREAM so that it prefixes lines written on it with LMARGIN spaces
  49    and limits them to RMARGIN columns total.  If WMARGIN >= 0, words that
  50    extend past RMARGIN are wrapped by replacing the whitespace before them
  51    with a newline and WMARGIN spaces.  Otherwise, chars beyond RMARGIN are
  52    simply dropped until a newline.  Returns STREAM after modifying it, or
  53    NULL if there was an error.  */
  54 FILE *line_wrap_stream (FILE *stream,
  55                         size_t lmargin, size_t rmargin, size_t wmargin);
  56
  57 /* Remove the hooks placed in STREAM by `line_wrap_stream'.  */
  58 void line_unwrap_stream (FILE *stream);
  59
  60 /* Returns true if STREAM is line wrapped.  */
  61 extern inline int line_wrapped (FILE *stream);
  62
  63 /* If STREAM is not line-wrapped return -1, else return its left margin.  */
  64 extern size_t line_wrap_lmargin (FILE *stream);
  65
  66 /* If STREAM is not line-wrapped return -1, else set its left margin to
  67    LMARGIN and return the old value.  */
  68 extern size_t line_wrap_set_lmargin (FILE *stream, size_t lmargin);
  69
  70 /* If STREAM is not line-wrapped return -1, else return its left margin.  */
  71 extern size_t line_wrap_rmargin (FILE *stream);
  72
  73 /* If STREAM is not line-wrapped return -1, else set its right margin to
  74    RMARGIN and return the old value.  */
  75 extern size_t line_wrap_set_rmargin (FILE *stream, size_t rmargin);
  76
  77 /* If STREAM is not line-wrapped return -1, else return its wrap margin.  */
  78 extern size_t line_wrap_wmargin (FILE *stream);
  79
  80 /* If STREAM is not line-wrapped return -1, else set its left margin to
  81    WMARGIN and return the old value.  */
  82 extern size_t line_wrap_set_wmargin (FILE *stream, size_t wmargin);
  83
  84 /* If STREAM is not line-wrapped return -1, else return the column number of
  85    the current output point.  */
  86 extern size_t line_wrap_point (FILE *stream);
  87
  88
  89 #ifdef  __OPTIMIZE__
  90
  91 extern void __line_wrap_output (FILE *, int); /* private */
  92
  93 /* Returns true if STREAM is line wrapped.  */
  94 extern inline int
  95 line_wrapped (FILE *stream)
  96 {
  97   return (stream->__room_funcs.__output == &__line_wrap_output);
  98 }
  99
 100 /* If STREAM is not line-wrapped return -1, else return its left margin.  */
 101 extern inline size_t
 102 line_wrap_lmargin (FILE *stream)
 103 {
 104   if (! line_wrapped (stream))
 105     return -1;
 106   return ((struct line_wrap_data *)stream->__cookie)->lmargin;
 107 }
 108
 109 /* If STREAM is not line-wrapped return -1, else set its left margin to
 110    LMARGIN and return the old value.  */
 111 extern inline size_t
 112 line_wrap_set_lmargin (FILE *stream, size_t lmargin)
 113 {
 114   if (! line_wrapped (stream))
 115     return -1;
 116   else
 117     {
 118       struct line_wrap_data *d = stream->__cookie;
 119       size_t old = d->lmargin;
 120       d->lmargin = lmargin;
 121       return old;
 122     }
 123 }
 124
 125 /* If STREAM is not line-wrapped return -1, else return its left margin.  */
 126 extern inline size_t
 127 line_wrap_rmargin (FILE *stream)
 128 {
 129   if (! line_wrapped (stream))
 130     return -1;
 131   return ((struct line_wrap_data *)stream->__cookie)->rmargin;
 132 }
 133
 134 /* If STREAM is not line-wrapped return -1, else set its right margin to
 135    RMARGIN and return the old value.  */
 136 extern inline size_t
 137 line_wrap_set_rmargin (FILE *stream, size_t rmargin)
 138 {
 139   if (! line_wrapped (stream))
 140     return -1;
 141   else
 142     {
 143       struct line_wrap_data *d = stream->__cookie;
 144       size_t old = d->rmargin;
 145       d->rmargin = rmargin;
 146       return old;
 147     }
 148 }
 149
 150 /* If STREAM is not line-wrapped return -1, else return its wrap margin.  */
 151 extern inline size_t
 152 line_wrap_wmargin (FILE *stream)
 153 {
 154   if (! line_wrapped (stream))
 155     return -1;
 156   return ((struct line_wrap_data *)stream->__cookie)->wmargin;
 157 }
 158
 159 /* If STREAM is not line-wrapped return -1, else set its left margin to
 160    WMARGIN and return the old value.  */
 161 extern inline size_t
 162 line_wrap_set_wmargin (FILE *stream, size_t wmargin)
 163 {
 164   if (! line_wrapped (stream))
 165     return -1;
 166   else
 167     {
 168       struct line_wrap_data *d = stream->__cookie;
 169       size_t old = d->wmargin;
 170       d->wmargin = wmargin;
 171       return old;
 172     }
 173 }
 174
 175 /* If STREAM is not line-wrapped return -1, else return the column number of
 176    the current output point.  */
 177 extern inline size_t
 178 line_wrap_point (FILE *stream)
 179 {
 180   if (! line_wrapped (stream))
 181     return -1;
 182   return ((struct line_wrap_data *)stream->__cookie)->point;
 183 }
 184
 185 #endif /* Optimizing.  */
 186
 187 __END_DECLS
 188
 189 #endif /* __LINEWRAP_H__ */