1 /* Word-wrapping and line-truncating streams
2 Copyright (C) 1997, 1998 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 Library General Public License as
8 published by the Free Software Foundation; either version 2 of the
9 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 Library General Public License for more details.
16 You should have received a copy of the GNU Library General Public
17 License along with the GNU C Library; see the file COPYING.LIB. If not,
18 write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330,
19 Boston, MA 02111-1307, USA. */
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
44 # include <libio/libioP.h>
45 # define __vsnprintf(s, l, f, a) _IO_vsnprintf (s, l, f, a)
48 #define INIT_BUF_SIZE 200
49 #define PRINTF_SIZE_GUESS 150
51 /* Return an argp_fmtstream that outputs to STREAM, and which prefixes lines
52 written on it with LMARGIN spaces and limits them to RMARGIN columns
53 total. If WMARGIN >= 0, words that extend past RMARGIN are wrapped by
54 replacing the whitespace before them with a newline and WMARGIN spaces.
55 Otherwise, chars beyond RMARGIN are simply dropped until a newline.
56 Returns NULL if there was an error. */
58 __argp_make_fmtstream (FILE *stream
,
59 size_t lmargin
, size_t rmargin
, ssize_t wmargin
)
61 argp_fmtstream_t fs
= malloc (sizeof (struct argp_fmtstream
));
66 fs
->lmargin
= lmargin
;
67 fs
->rmargin
= rmargin
;
68 fs
->wmargin
= wmargin
;
72 fs
->buf
= malloc (INIT_BUF_SIZE
);
81 fs
->end
= fs
->buf
+ INIT_BUF_SIZE
;
88 weak_alias (__argp_make_fmtstream
, argp_make_fmtstream
)
91 /* Flush FS to its stream, and free it (but don't close the stream). */
93 __argp_fmtstream_free (argp_fmtstream_t fs
)
95 __argp_fmtstream_update (fs
);
97 fwrite_unlocked (fs
->buf
, 1, fs
->p
- fs
->buf
, fs
->stream
);
102 weak_alias (__argp_fmtstream_free
, argp_fmtstream_free
)
105 /* Process FS's buffer so that line wrapping is done from POINT_OFFS to the
106 end of its buffer. This code is mostly from glibc stdio/linewrap.c. */
108 __argp_fmtstream_update (argp_fmtstream_t fs
)
113 /* Scan the buffer for newlines. */
114 buf
= fs
->buf
+ fs
->point_offs
;
119 if (fs
->point_col
== 0 && fs
->lmargin
!= 0)
121 /* We are starting a new line. Print spaces to the left margin. */
122 const size_t pad
= fs
->lmargin
;
123 if (fs
->p
+ pad
< fs
->end
)
125 /* We can fit in them in the buffer by moving the
126 buffer text up and filling in the beginning. */
127 memmove (buf
+ pad
, buf
, fs
->p
- buf
);
128 fs
->p
+= pad
; /* Compensate for bigger buffer. */
129 memset (buf
, ' ', pad
); /* Fill in the spaces. */
130 buf
+= pad
; /* Don't bother searching them. */
134 /* No buffer space for spaces. Must flush. */
136 for (i
= 0; i
< pad
; i
++)
137 putc_unlocked (' ', fs
->stream
);
143 nl
= memchr (buf
, '\n', len
);
145 if (fs
->point_col
< 0)
150 /* The buffer ends in a partial line. */
152 if (fs
->point_col
+ len
< fs
->rmargin
)
154 /* The remaining buffer text is a partial line and fits
155 within the maximum line width. Advance point for the
156 characters to be written and stop scanning. */
157 fs
->point_col
+= len
;
161 /* Set the end-of-line pointer for the code below to
162 the end of the buffer. */
165 else if (fs
->point_col
+ (nl
- buf
) < (ssize_t
) fs
->rmargin
)
167 /* The buffer contains a full line that fits within the maximum
168 line width. Reset point and scan the next line. */
174 /* This line is too long. */
179 /* Truncate the line by overwriting the excess with the
180 newline and anything after it in the buffer. */
183 memmove (buf
+ (r
- fs
->point_col
), nl
, fs
->p
- nl
);
184 fs
->p
-= buf
+ (r
- fs
->point_col
) - nl
;
185 /* Reset point for the next line and start scanning it. */
187 buf
+= r
+ 1; /* Skip full line plus \n. */
191 /* The buffer ends with a partial line that is beyond the
192 maximum line width. Advance point for the characters
193 written, and discard those past the max from the buffer. */
194 fs
->point_col
+= len
;
195 fs
->p
-= fs
->point_col
- r
;
201 /* Do word wrap. Go to the column just past the maximum line
202 width and scan back for the beginning of the word there.
203 Then insert a line break. */
208 p
= buf
+ (r
+ 1 - fs
->point_col
);
209 while (p
>= buf
&& !isblank (*p
))
211 nextline
= p
+ 1; /* This will begin the next line. */
215 /* Swallow separating blanks. */
219 while (p
>= buf
&& isblank (*p
));
220 nl
= p
+ 1; /* The newline will replace the first blank. */
224 /* A single word that is greater than the maximum line width.
225 Oh well. Put it on an overlong line by itself. */
226 p
= buf
+ (r
+ 1 - fs
->point_col
);
227 /* Find the end of the long word. */
230 while (p
< nl
&& !isblank (*p
));
233 /* It already ends a line. No fussing required. */
238 /* We will move the newline to replace the first blank. */
240 /* Swallow separating blanks. */
243 while (isblank (*p
));
244 /* The next line will start here. */
248 /* Note: There are a bunch of tests below for
249 NEXTLINE == BUF + LEN + 1; this case is where NL happens to fall
250 at the end of the buffer, and NEXTLINE is in fact empty (and so
251 we need not be careful to maintain its contents). */
253 if (nextline
== buf
+ len
+ 1
254 ? fs
->end
- nl
< fs
->wmargin
+ 1
255 : nextline
- (nl
+ 1) < fs
->wmargin
)
257 /* The margin needs more blanks than we removed. */
258 if (fs
->end
- fs
->p
> fs
->wmargin
+ 1)
259 /* Make some space for them. */
261 size_t mv
= fs
->p
- nextline
;
262 memmove (nl
+ 1 + fs
->wmargin
, nextline
, mv
);
263 nextline
= nl
+ 1 + fs
->wmargin
;
264 len
= nextline
+ mv
- buf
;
268 /* Output the first line so we can use the space. */
271 fwrite_unlocked (fs
->buf
, 1, nl
- fs
->buf
, fs
->stream
);
272 putc_unlocked ('\n', fs
->stream
);
273 len
+= buf
- fs
->buf
;
278 /* We can fit the newline and blanks in before
282 if (nextline
- nl
>= fs
->wmargin
283 || (nextline
== buf
+ len
+ 1 && fs
->end
- nextline
>= fs
->wmargin
))
284 /* Add blanks up to the wrap margin column. */
285 for (i
= 0; i
< fs
->wmargin
; ++i
)
288 for (i
= 0; i
< fs
->wmargin
; ++i
)
289 putc_unlocked (' ', fs
->stream
);
291 /* Copy the tail of the original buffer into the current buffer
294 memmove (nl
, nextline
, buf
+ len
- nextline
);
295 len
-= nextline
- buf
;
297 /* Continue the scan on the remaining lines in the buffer. */
300 /* Restore bufp to include all the remaining text. */
303 /* Reset the counter of what has been output this line. If wmargin
304 is 0, we want to avoid the lmargin getting added, so we set
305 point_col to a magic value of -1 in that case. */
306 fs
->point_col
= fs
->wmargin
? fs
->wmargin
: -1;
310 /* Remember that we've scanned as far as the end of the buffer. */
311 fs
->point_offs
= fs
->p
- fs
->buf
;
314 /* Ensure that FS has space for AMOUNT more bytes in its buffer, either by
315 growing the buffer, or by flushing it. True is returned iff we succeed. */
317 __argp_fmtstream_ensure (struct argp_fmtstream
*fs
, size_t amount
)
319 if ((size_t) (fs
->end
- fs
->p
) < amount
)
323 /* Flush FS's buffer. */
324 __argp_fmtstream_update (fs
);
326 wrote
= fwrite_unlocked (fs
->buf
, 1, fs
->p
- fs
->buf
, fs
->stream
);
327 if (wrote
== fs
->p
- fs
->buf
)
335 fs
->point_offs
-= wrote
;
336 memmove (fs
->buf
, fs
->buf
+ wrote
, fs
->p
- fs
->buf
);
340 if ((size_t) (fs
->end
- fs
->buf
) < amount
)
341 /* Gotta grow the buffer. */
343 size_t new_size
= fs
->end
- fs
->buf
+ amount
;
344 char *new_buf
= realloc (fs
->buf
, new_size
);
348 __set_errno (ENOMEM
);
353 fs
->end
= new_buf
+ new_size
;
362 __argp_fmtstream_printf (struct argp_fmtstream
*fs
, const char *fmt
, ...)
365 size_t size_guess
= PRINTF_SIZE_GUESS
; /* How much space to reserve. */
371 if (! __argp_fmtstream_ensure (fs
, size_guess
))
373 size_guess
+= size_guess
;
375 va_start (args
, fmt
);
376 out
= __vsnprintf (fs
->p
, fs
->end
- fs
->p
, fmt
, args
);
386 weak_alias (__argp_fmtstream_printf
, argp_fmtstream_printf
)
389 #endif /* !ARGP_FMTSTREAM_USE_LINEWRAP */