1 /* Word-wrapping and line-truncating streams
2 Copyright (C) 1997,1998,1999,2001,2002,2003 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 This program is free software; you can redistribute it and/or modify
7 it under the terms of the GNU General Public License as published by
8 the Free Software Foundation; either version 2, or (at your option)
11 This program 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
14 GNU General Public License for more details.
16 You should have received a copy of the GNU General Public License along
17 with this program; if not, write to the Free Software Foundation,
18 Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. */
20 /* This package emulates glibc `line_wrap_stream' semantics for systems that
33 #include "argp-fmtstream.h"
34 #include "argp-namefrob.h"
36 #ifndef ARGP_FMTSTREAM_USE_LINEWRAP
39 #define isblank(ch) ((ch)==' ' || (ch)=='\t')
42 #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)
63 fs = (struct argp_fmtstream *) malloc (sizeof (struct argp_fmtstream));
68 fs->lmargin = lmargin;
69 fs->rmargin = rmargin;
70 fs->wmargin = wmargin;
74 fs->buf = (char *) malloc (INIT_BUF_SIZE);
83 fs->end = fs->buf + INIT_BUF_SIZE;
92 weak_alias (__argp_make_fmtstream, argp_make_fmtstream)
96 /* Flush FS to its stream, and free it (but don't close the stream). */
98 __argp_fmtstream_free (argp_fmtstream_t fs)
100 __argp_fmtstream_update (fs);
104 if (_IO_fwide (fs->stream, 0) > 0)
105 __fwprintf (fs->stream, L"%.*s", (int) (fs->p - fs->buf), fs->buf);
108 fwrite_unlocked (fs->buf, 1, fs->p - fs->buf, fs->stream);
116 weak_alias (__argp_fmtstream_free, argp_fmtstream_free)
120 /* Process FS's buffer so that line wrapping is done from POINT_OFFS to the
121 end of its buffer. This code is mostly from glibc stdio/linewrap.c. */
123 __argp_fmtstream_update (argp_fmtstream_t fs)
128 /* Scan the buffer for newlines. */
129 buf = fs->buf + fs->point_offs;
134 if (fs->point_col == 0 && fs->lmargin != 0)
136 /* We are starting a new line. Print spaces to the left margin. */
137 const size_t pad = fs->lmargin;
138 if (fs->p + pad < fs->end)
140 /* We can fit in them in the buffer by moving the
141 buffer text up and filling in the beginning. */
142 memmove (buf + pad, buf, fs->p - buf);
143 fs->p += pad; /* Compensate for bigger buffer. */
144 memset (buf, ' ', pad); /* Fill in the spaces. */
145 buf += pad; /* Don't bother searching them. */
149 /* No buffer space for spaces. Must flush. */
151 for (i = 0; i < pad; i++)
154 if (_IO_fwide (fs->stream, 0) > 0)
155 putwc_unlocked (L' ', fs->stream);
158 putc_unlocked (' ', fs->stream);
165 nl = memchr (buf, '\n', len);
167 if (fs->point_col < 0)
172 /* The buffer ends in a partial line. */
174 if (fs->point_col + len < fs->rmargin)
176 /* The remaining buffer text is a partial line and fits
177 within the maximum line width. Advance point for the
178 characters to be written and stop scanning. */
179 fs->point_col += len;
183 /* Set the end-of-line pointer for the code below to
184 the end of the buffer. */
187 else if (fs->point_col + (nl - buf) < (ssize_t) fs->rmargin)
189 /* The buffer contains a full line that fits within the maximum
190 line width. Reset point and scan the next line. */
196 /* This line is too long. */
201 /* Truncate the line by overwriting the excess with the
202 newline and anything after it in the buffer. */
205 memmove (buf + (r - fs->point_col), nl, fs->p - nl);
206 fs->p -= buf + (r - fs->point_col) - nl;
207 /* Reset point for the next line and start scanning it. */
209 buf += r + 1; /* Skip full line plus \n. */
213 /* The buffer ends with a partial line that is beyond the
214 maximum line width. Advance point for the characters
215 written, and discard those past the max from the buffer. */
216 fs->point_col += len;
217 fs->p -= fs->point_col - r;
223 /* Do word wrap. Go to the column just past the maximum line
224 width and scan back for the beginning of the word there.
225 Then insert a line break. */
230 p = buf + (r + 1 - fs->point_col);
231 while (p >= buf && !isblank (*p))
233 nextline = p + 1; /* This will begin the next line. */
237 /* Swallow separating blanks. */
241 while (p >= buf && isblank (*p));
242 nl = p + 1; /* The newline will replace the first blank. */
246 /* A single word that is greater than the maximum line width.
247 Oh well. Put it on an overlong line by itself. */
248 p = buf + (r + 1 - fs->point_col);
249 /* Find the end of the long word. */
252 while (p < nl && !isblank (*p));
255 /* It already ends a line. No fussing required. */
260 /* We will move the newline to replace the first blank. */
262 /* Swallow separating blanks. */
265 while (isblank (*p));
266 /* The next line will start here. */
270 /* Note: There are a bunch of tests below for
271 NEXTLINE == BUF + LEN + 1; this case is where NL happens to fall
272 at the end of the buffer, and NEXTLINE is in fact empty (and so
273 we need not be careful to maintain its contents). */
275 if ((nextline == buf + len + 1
276 ? fs->end - nl < fs->wmargin + 1
277 : nextline - (nl + 1) < fs->wmargin)
280 /* The margin needs more blanks than we removed. */
281 if (fs->end - fs->p > fs->wmargin + 1)
282 /* Make some space for them. */
284 size_t mv = fs->p - nextline;
285 memmove (nl + 1 + fs->wmargin, nextline, mv);
286 nextline = nl + 1 + fs->wmargin;
287 len = nextline + mv - buf;
291 /* Output the first line so we can use the space. */
294 if (_IO_fwide (fs->stream, 0) > 0)
295 __fwprintf (fs->stream, L"%.*s\n",
296 (int) (nl - fs->buf), fs->buf);
301 fwrite_unlocked (fs->buf, 1, nl - fs->buf, fs->stream);
302 putc_unlocked ('\n', fs->stream);
304 len += buf - fs->buf;
309 /* We can fit the newline and blanks in before
313 if (nextline - nl >= fs->wmargin
314 || (nextline == buf + len + 1 && fs->end - nextline >= fs->wmargin))
315 /* Add blanks up to the wrap margin column. */
316 for (i = 0; i < fs->wmargin; ++i)
319 for (i = 0; i < fs->wmargin; ++i)
321 if (_IO_fwide (fs->stream, 0) > 0)
322 putwc_unlocked (L' ', fs->stream);
325 putc_unlocked (' ', fs->stream);
327 /* Copy the tail of the original buffer into the current buffer
330 memmove (nl, nextline, buf + len - nextline);
331 len -= nextline - buf;
333 /* Continue the scan on the remaining lines in the buffer. */
336 /* Restore bufp to include all the remaining text. */
339 /* Reset the counter of what has been output this line. If wmargin
340 is 0, we want to avoid the lmargin getting added, so we set
341 point_col to a magic value of -1 in that case. */
342 fs->point_col = fs->wmargin ? fs->wmargin : -1;
346 /* Remember that we've scanned as far as the end of the buffer. */
347 fs->point_offs = fs->p - fs->buf;
350 /* Ensure that FS has space for AMOUNT more bytes in its buffer, either by
351 growing the buffer, or by flushing it. True is returned iff we succeed. */
353 __argp_fmtstream_ensure (struct argp_fmtstream *fs, size_t amount)
355 if ((size_t) (fs->end - fs->p) < amount)
359 /* Flush FS's buffer. */
360 __argp_fmtstream_update (fs);
363 if (_IO_fwide (fs->stream, 0) > 0)
365 __fwprintf (fs->stream, L"%.*s", (int) (fs->p - fs->buf), fs->buf);
366 wrote = fs->p - fs->buf;
370 wrote = fwrite_unlocked (fs->buf, 1, fs->p - fs->buf, fs->stream);
371 if (wrote == fs->p - fs->buf)
379 fs->point_offs -= wrote;
380 memmove (fs->buf, fs->buf + wrote, fs->p - fs->buf);
384 if ((size_t) (fs->end - fs->buf) < amount)
385 /* Gotta grow the buffer. */
387 size_t new_size = fs->end - fs->buf + amount;
388 char *new_buf = realloc (fs->buf, new_size);
392 __set_errno (ENOMEM);
397 fs->end = new_buf + new_size;
406 __argp_fmtstream_printf (struct argp_fmtstream *fs, const char *fmt, ...)
410 size_t size_guess = PRINTF_SIZE_GUESS; /* How much space to reserve. */
416 if (! __argp_fmtstream_ensure (fs, size_guess))
419 va_start (args, fmt);
420 avail = fs->end - fs->p;
421 out = __vsnprintf (fs->p, avail, fmt, args);
423 if ((size_t) out >= avail)
424 size_guess = out + 1;
426 while ((size_t) out >= avail);
435 weak_alias (__argp_fmtstream_printf, argp_fmtstream_printf)
439 #endif /* !ARGP_FMTSTREAM_USE_LINEWRAP */