1 /* Word-wrapping and line-truncating streams
2 Copyright (C) 1997, 1998, 1999, 2001 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4 Written by Miles Bader <miles@gnu.ai.mit.edu>.
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, write to the Free
18 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
21 /* This package emulates glibc `line_wrap_stream' semantics for systems that
34 #include "argp-fmtstream.h"
35 #include "argp-namefrob.h"
37 #ifndef ARGP_FMTSTREAM_USE_LINEWRAP
40 #define isblank(ch) ((ch)==' ' || (ch)=='\t')
43 #if defined _LIBC && defined USE_IN_LIBIO
45 # include <libio/libioP.h>
46 # define __vsnprintf(s, l, f, a) _IO_vsnprintf (s, l, f, a)
49 #define INIT_BUF_SIZE 200
50 #define PRINTF_SIZE_GUESS 150
52 /* Return an argp_fmtstream that outputs to STREAM, and which prefixes lines
53 written on it with LMARGIN spaces and limits them to RMARGIN columns
54 total. If WMARGIN >= 0, words that extend past RMARGIN are wrapped by
55 replacing the whitespace before them with a newline and WMARGIN spaces.
56 Otherwise, chars beyond RMARGIN are simply dropped until a newline.
57 Returns NULL if there was an error. */
59 __argp_make_fmtstream (FILE *stream
,
60 size_t lmargin
, size_t rmargin
, ssize_t wmargin
)
64 fs
= (struct argp_fmtstream
*) malloc (sizeof (struct argp_fmtstream
));
69 fs
->lmargin
= lmargin
;
70 fs
->rmargin
= rmargin
;
71 fs
->wmargin
= wmargin
;
75 fs
->buf
= (char *) malloc (INIT_BUF_SIZE
);
84 fs
->end
= fs
->buf
+ INIT_BUF_SIZE
;
91 weak_alias (__argp_make_fmtstream
, argp_make_fmtstream
)
94 /* Flush FS to its stream, and free it (but don't close the stream). */
96 __argp_fmtstream_free (argp_fmtstream_t fs
)
98 __argp_fmtstream_update (fs
);
102 if (_IO_fwide (fs
->stream
, 0) > 0)
103 __fwprintf (fs
->stream
, L
"%.*s", (int) (fs
->p
- fs
->buf
), fs
->buf
);
106 fwrite_unlocked (fs
->buf
, 1, fs
->p
- fs
->buf
, fs
->stream
);
112 weak_alias (__argp_fmtstream_free
, argp_fmtstream_free
)
115 /* Process FS's buffer so that line wrapping is done from POINT_OFFS to the
116 end of its buffer. This code is mostly from glibc stdio/linewrap.c. */
118 __argp_fmtstream_update (argp_fmtstream_t fs
)
123 /* Scan the buffer for newlines. */
124 buf
= fs
->buf
+ fs
->point_offs
;
129 if (fs
->point_col
== 0 && fs
->lmargin
!= 0)
131 /* We are starting a new line. Print spaces to the left margin. */
132 const size_t pad
= fs
->lmargin
;
133 if (fs
->p
+ pad
< fs
->end
)
135 /* We can fit in them in the buffer by moving the
136 buffer text up and filling in the beginning. */
137 memmove (buf
+ pad
, buf
, fs
->p
- buf
);
138 fs
->p
+= pad
; /* Compensate for bigger buffer. */
139 memset (buf
, ' ', pad
); /* Fill in the spaces. */
140 buf
+= pad
; /* Don't bother searching them. */
144 /* No buffer space for spaces. Must flush. */
146 for (i
= 0; i
< pad
; i
++)
149 if (_IO_fwide (fs
->stream
, 0) > 0)
150 putwc_unlocked (L
' ', fs
->stream
);
153 putc_unlocked (' ', fs
->stream
);
160 nl
= memchr (buf
, '\n', len
);
162 if (fs
->point_col
< 0)
167 /* The buffer ends in a partial line. */
169 if (fs
->point_col
+ len
< fs
->rmargin
)
171 /* The remaining buffer text is a partial line and fits
172 within the maximum line width. Advance point for the
173 characters to be written and stop scanning. */
174 fs
->point_col
+= len
;
178 /* Set the end-of-line pointer for the code below to
179 the end of the buffer. */
182 else if (fs
->point_col
+ (nl
- buf
) < (ssize_t
) fs
->rmargin
)
184 /* The buffer contains a full line that fits within the maximum
185 line width. Reset point and scan the next line. */
191 /* This line is too long. */
196 /* Truncate the line by overwriting the excess with the
197 newline and anything after it in the buffer. */
200 memmove (buf
+ (r
- fs
->point_col
), nl
, fs
->p
- nl
);
201 fs
->p
-= buf
+ (r
- fs
->point_col
) - nl
;
202 /* Reset point for the next line and start scanning it. */
204 buf
+= r
+ 1; /* Skip full line plus \n. */
208 /* The buffer ends with a partial line that is beyond the
209 maximum line width. Advance point for the characters
210 written, and discard those past the max from the buffer. */
211 fs
->point_col
+= len
;
212 fs
->p
-= fs
->point_col
- r
;
218 /* Do word wrap. Go to the column just past the maximum line
219 width and scan back for the beginning of the word there.
220 Then insert a line break. */
225 p
= buf
+ (r
+ 1 - fs
->point_col
);
226 while (p
>= buf
&& !isblank (*p
))
228 nextline
= p
+ 1; /* This will begin the next line. */
232 /* Swallow separating blanks. */
236 while (p
>= buf
&& isblank (*p
));
237 nl
= p
+ 1; /* The newline will replace the first blank. */
241 /* A single word that is greater than the maximum line width.
242 Oh well. Put it on an overlong line by itself. */
243 p
= buf
+ (r
+ 1 - fs
->point_col
);
244 /* Find the end of the long word. */
247 while (p
< nl
&& !isblank (*p
));
250 /* It already ends a line. No fussing required. */
255 /* We will move the newline to replace the first blank. */
257 /* Swallow separating blanks. */
260 while (isblank (*p
));
261 /* The next line will start here. */
265 /* Note: There are a bunch of tests below for
266 NEXTLINE == BUF + LEN + 1; this case is where NL happens to fall
267 at the end of the buffer, and NEXTLINE is in fact empty (and so
268 we need not be careful to maintain its contents). */
270 if (nextline
== buf
+ len
+ 1
271 ? fs
->end
- nl
< fs
->wmargin
+ 1
272 : nextline
- (nl
+ 1) < fs
->wmargin
)
274 /* The margin needs more blanks than we removed. */
275 if (fs
->end
- fs
->p
> fs
->wmargin
+ 1)
276 /* Make some space for them. */
278 size_t mv
= fs
->p
- nextline
;
279 memmove (nl
+ 1 + fs
->wmargin
, nextline
, mv
);
280 nextline
= nl
+ 1 + fs
->wmargin
;
281 len
= nextline
+ mv
- buf
;
285 /* Output the first line so we can use the space. */
288 if (_IO_fwide (fs
->stream
, 0) > 0)
289 __fwprintf (fs
->stream
, L
"%.*s\n",
290 (int) (nl
- fs
->buf
), fs
->buf
);
295 fwrite_unlocked (fs
->buf
, 1, nl
- fs
->buf
, fs
->stream
);
296 putc_unlocked ('\n', fs
->stream
);
298 len
+= buf
- fs
->buf
;
303 /* We can fit the newline and blanks in before
307 if (nextline
- nl
>= fs
->wmargin
308 || (nextline
== buf
+ len
+ 1 && fs
->end
- nextline
>= fs
->wmargin
))
309 /* Add blanks up to the wrap margin column. */
310 for (i
= 0; i
< fs
->wmargin
; ++i
)
313 for (i
= 0; i
< fs
->wmargin
; ++i
)
315 if (_IO_fwide (fs
->stream
, 0) > 0)
316 putwc_unlocked (L
' ', fs
->stream
);
319 putc_unlocked (' ', fs
->stream
);
321 /* Copy the tail of the original buffer into the current buffer
324 memmove (nl
, nextline
, buf
+ len
- nextline
);
325 len
-= nextline
- buf
;
327 /* Continue the scan on the remaining lines in the buffer. */
330 /* Restore bufp to include all the remaining text. */
333 /* Reset the counter of what has been output this line. If wmargin
334 is 0, we want to avoid the lmargin getting added, so we set
335 point_col to a magic value of -1 in that case. */
336 fs
->point_col
= fs
->wmargin
? fs
->wmargin
: -1;
340 /* Remember that we've scanned as far as the end of the buffer. */
341 fs
->point_offs
= fs
->p
- fs
->buf
;
344 /* Ensure that FS has space for AMOUNT more bytes in its buffer, either by
345 growing the buffer, or by flushing it. True is returned iff we succeed. */
347 __argp_fmtstream_ensure (struct argp_fmtstream
*fs
, size_t amount
)
349 if ((size_t) (fs
->end
- fs
->p
) < amount
)
353 /* Flush FS's buffer. */
354 __argp_fmtstream_update (fs
);
357 if (_IO_fwide (fs
->stream
, 0) > 0)
359 __fwprintf (fs
->stream
, L
"%.*s", (int) (fs
->p
- fs
->buf
), fs
->buf
);
360 wrote
= fs
->p
- fs
->buf
;
364 wrote
= fwrite_unlocked (fs
->buf
, 1, fs
->p
- fs
->buf
, fs
->stream
);
365 if (wrote
== fs
->p
- fs
->buf
)
373 fs
->point_offs
-= wrote
;
374 memmove (fs
->buf
, fs
->buf
+ wrote
, fs
->p
- fs
->buf
);
378 if ((size_t) (fs
->end
- fs
->buf
) < amount
)
379 /* Gotta grow the buffer. */
381 size_t new_size
= fs
->end
- fs
->buf
+ amount
;
382 char *new_buf
= realloc (fs
->buf
, new_size
);
386 __set_errno (ENOMEM
);
391 fs
->end
= new_buf
+ new_size
;
400 __argp_fmtstream_printf (struct argp_fmtstream
*fs
, const char *fmt
, ...)
404 size_t size_guess
= PRINTF_SIZE_GUESS
; /* How much space to reserve. */
410 if (! __argp_fmtstream_ensure (fs
, size_guess
))
413 va_start (args
, fmt
);
414 avail
= fs
->end
- fs
->p
;
415 out
= __vsnprintf (fs
->p
, avail
, fmt
, args
);
418 size_guess
= out
+ 1;
420 while (out
>= avail
);
427 weak_alias (__argp_fmtstream_printf
, argp_fmtstream_printf
)
430 #endif /* !ARGP_FMTSTREAM_USE_LINEWRAP */