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     ssize_t wmargin;            /* Margin to wrap to, or -1 to truncate.  */
  38
  39     /* Point in stdio buffer to which we've processed for wrapping, but
  40        not output.  */
  41     size_t point_offs;
  42     /* Output column at POINT_OFFS, or -1 meaning 0 but don't add lmargin.  */
  43     ssize_t point_col;
  44
  45     /* Original cookie and hooks from the stream.  */
  46     void *cookie;
  47     void (*output) (FILE *, int);
  48     __io_close_fn *close;
  49     __io_fileno_fn *fileno;
  50     __io_seek_fn *seek;
  51   };
  52 \f
  53 /* Modify STREAM so that it prefixes lines written on it with LMARGIN spaces
  54    and limits them to RMARGIN columns total.  If WMARGIN >= 0, words that
  55    extend past RMARGIN are wrapped by replacing the whitespace before them
  56    with a newline and WMARGIN spaces.  Otherwise, chars beyond RMARGIN are
  57    simply dropped until a newline.  Returns STREAM after modifying it, or
  58    NULL if there was an error.  */
  59 FILE *line_wrap_stream (FILE *stream,
  60                         size_t lmargin, size_t rmargin, ssize_t wmargin);
  61
  62 /* Remove the hooks placed in STREAM by `line_wrap_stream'.  */
  63 void line_unwrap_stream (FILE *stream);
  64
  65 /* Returns true if STREAM is line wrapped.  */
  66 extern inline int line_wrapped (FILE *stream);
  67
  68 /* If STREAM is not line-wrapped return -1, else return its left margin.  */
  69 extern size_t line_wrap_lmargin (FILE *stream);
  70
  71 /* If STREAM is not line-wrapped return -1, else set its left margin to
  72    LMARGIN and return the old value.  */
  73 extern size_t line_wrap_set_lmargin (FILE *stream, size_t lmargin);
  74
  75 /* If STREAM is not line-wrapped return -1, else return its left margin.  */
  76 extern size_t line_wrap_rmargin (FILE *stream);
  77
  78 /* If STREAM is not line-wrapped return -1, else set its right margin to
  79    RMARGIN and return the old value.  */
  80 extern size_t line_wrap_set_rmargin (FILE *stream, size_t rmargin);
  81
  82 /* If STREAM is not line-wrapped return -1, else return its wrap margin.  */
  83 extern size_t line_wrap_wmargin (FILE *stream);
  84
  85 /* If STREAM is not line-wrapped return -1, else set its left margin to
  86    WMARGIN and return the old value.  */
  87 extern size_t line_wrap_set_wmargin (FILE *stream, size_t wmargin);
  88
  89 /* If STREAM is not line-wrapped return -1, else return the column number of
  90    the current output point.  */
  91 extern size_t line_wrap_point (FILE *stream);
  92
  93 #ifdef  __OPTIMIZE__
  94
  95 extern void __line_wrap_output (FILE *, int); /* private */
  96
  97 /* If STREAM is not line-wrapped, return 0.  Otherwise all pending text
  98    buffered text in STREAM so that the POINT_OFFS field refers to the last
  99    position in the stdio buffer, and return the line wrap state object for
 100    STREAM.  Since all text has been processed, this means that (1) the
 101    POINT_COL field refers to the column at which any new text would be added,
 102    and (2) any changes to the margin parameters will only affect new text.  */
 103 extern struct line_wrap_data *__line_wrap_update (FILE *stream); /* private */
 104
 105 /* Returns true if STREAM is line wrapped.  */
 106 extern inline int
 107 line_wrapped (FILE *stream)
 108 {
 109   return (stream->__room_funcs.__output == &__line_wrap_output);
 110 }
 111
 112 /* If STREAM is not line-wrapped return -1, else return its left margin.  */
 113 extern inline size_t
 114 line_wrap_lmargin (FILE *stream)
 115 {
 116   if (! line_wrapped (stream))
 117     return -1;
 118   return ((struct line_wrap_data *)stream->__cookie)->lmargin;
 119 }
 120
 121 /* If STREAM is not line-wrapped return -1, else set its left margin to
 122    LMARGIN and return the old value.  */
 123 extern inline size_t
 124 line_wrap_set_lmargin (FILE *stream, size_t lmargin)
 125 {
 126   struct line_wrap_data *d = __line_wrap_update (stream);
 127   if (d)
 128     {
 129       size_t old = d->lmargin;
 130       d->lmargin = lmargin;
 131       return old;
 132     }
 133   else
 134     return -1;
 135 }
 136
 137 /* If STREAM is not line-wrapped return -1, else return its left margin.  */
 138 extern inline size_t
 139 line_wrap_rmargin (FILE *stream)
 140 {
 141   if (! line_wrapped (stream))
 142     return -1;
 143   return ((struct line_wrap_data *)stream->__cookie)->rmargin;
 144 }
 145
 146 /* If STREAM is not line-wrapped return -1, else set its right margin to
 147    RMARGIN and return the old value.  */
 148 extern inline size_t
 149 line_wrap_set_rmargin (FILE *stream, size_t rmargin)
 150 {
 151   struct line_wrap_data *d = __line_wrap_update (stream);
 152   if (d)
 153     {
 154       size_t old = d->rmargin;
 155       d->rmargin = rmargin;
 156       return old;
 157     }
 158   else
 159     return -1;
 160 }
 161
 162 /* If STREAM is not line-wrapped return -1, else return its wrap margin.  */
 163 extern inline size_t
 164 line_wrap_wmargin (FILE *stream)
 165 {
 166   if (! line_wrapped (stream))
 167     return -1;
 168   return ((struct line_wrap_data *)stream->__cookie)->wmargin;
 169 }
 170
 171 /* If STREAM is not line-wrapped return -1, else set its left margin to
 172    WMARGIN and return the old value.  */
 173 extern inline size_t
 174 line_wrap_set_wmargin (FILE *stream, size_t wmargin)
 175 {
 176   struct line_wrap_data *d = __line_wrap_update (stream);
 177   if (d)
 178     {
 179       size_t old = d->wmargin;
 180       d->wmargin = wmargin;
 181       return old;
 182     }
 183   else
 184     return -1;
 185 }
 186
 187 /* If STREAM is not line-wrapped return -1, else return the column number of
 188    the current output point.  */
 189 extern inline size_t
 190 line_wrap_point (FILE *stream)
 191 {
 192   struct line_wrap_data *d = __line_wrap_update (stream);
 193   return d ? (d->point_col >= 0 ? d->point_col : 0) : -1;
 194 }
 195
 196 #endif /* Optimizing.  */
 197
 198 __END_DECLS
 199
 200 #endif /* __LINEWRAP_H__ */