1 /* Word-wrapping and line-truncating streams
2 Copyright (C) 1997-2014 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, see
18 <http://www.gnu.org/licenses/>. */
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')
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);
103 __fxprintf (fs->stream, "%.*s", (int) (fs->p - fs->buf), fs->buf);
111 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++)
148 if (_IO_fwide (fs->stream, 0) > 0)
149 putwc_unlocked (L' ', fs->stream);
151 putc_unlocked (' ', fs->stream);
158 nl = memchr (buf, '\n', len);
160 if (fs->point_col < 0)
165 /* The buffer ends in a partial line. */
167 if (fs->point_col + len < fs->rmargin)
169 /* The remaining buffer text is a partial line and fits
170 within the maximum line width. Advance point for the
171 characters to be written and stop scanning. */
172 fs->point_col += len;
176 /* Set the end-of-line pointer for the code below to
177 the end of the buffer. */
180 else if (fs->point_col + (nl - buf) < (ssize_t) fs->rmargin)
182 /* The buffer contains a full line that fits within the maximum
183 line width. Reset point and scan the next line. */
189 /* This line is too long. */
194 /* Truncate the line by overwriting the excess with the
195 newline and anything after it in the buffer. */
198 memmove (buf + (r - fs->point_col), nl, fs->p - nl);
199 fs->p -= buf + (r - fs->point_col) - nl;
200 /* Reset point for the next line and start scanning it. */
202 buf += r + 1; /* Skip full line plus \n. */
206 /* The buffer ends with a partial line that is beyond the
207 maximum line width. Advance point for the characters
208 written, and discard those past the max from the buffer. */
209 fs->point_col += len;
210 fs->p -= fs->point_col - r;
216 /* Do word wrap. Go to the column just past the maximum line
217 width and scan back for the beginning of the word there.
218 Then insert a line break. */
223 p = buf + (r + 1 - fs->point_col);
224 while (p >= buf && !isblank (*p))
226 nextline = p + 1; /* This will begin the next line. */
230 /* Swallow separating blanks. */
234 while (p >= buf && isblank (*p));
235 nl = p + 1; /* The newline will replace the first blank. */
239 /* A single word that is greater than the maximum line width.
240 Oh well. Put it on an overlong line by itself. */
241 p = buf + (r + 1 - fs->point_col);
242 /* Find the end of the long word. */
245 while (p < nl && !isblank (*p));
248 /* It already ends a line. No fussing required. */
253 /* We will move the newline to replace the first blank. */
255 /* Swallow separating blanks. */
258 while (isblank (*p));
259 /* The next line will start here. */
263 /* Note: There are a bunch of tests below for
264 NEXTLINE == BUF + LEN + 1; this case is where NL happens to fall
265 at the end of the buffer, and NEXTLINE is in fact empty (and so
266 we need not be careful to maintain its contents). */
268 if ((nextline == buf + len + 1
269 ? fs->end - nl < fs->wmargin + 1
270 : nextline - (nl + 1) < fs->wmargin)
273 /* The margin needs more blanks than we removed. */
274 if (fs->end - fs->p > fs->wmargin + 1)
275 /* Make some space for them. */
277 size_t mv = fs->p - nextline;
278 memmove (nl + 1 + fs->wmargin, nextline, mv);
279 nextline = nl + 1 + fs->wmargin;
280 len = nextline + mv - buf;
284 /* Output the first line so we can use the space. */
287 __fxprintf (fs->stream, "%.*s\n",
288 (int) (nl - fs->buf), fs->buf);
291 fwrite_unlocked (fs->buf, 1, nl - fs->buf, fs->stream);
292 putc_unlocked ('\n', fs->stream);
295 len += buf - fs->buf;
300 /* We can fit the newline and blanks in before
304 if (nextline - nl >= fs->wmargin
305 || (nextline == buf + len + 1 && fs->end - nextline >= fs->wmargin))
306 /* Add blanks up to the wrap margin column. */
307 for (i = 0; i < fs->wmargin; ++i)
310 for (i = 0; i < fs->wmargin; ++i)
311 if (_IO_fwide (fs->stream, 0) > 0)
312 putwc_unlocked (L' ', fs->stream);
314 putc_unlocked (' ', fs->stream);
316 /* Copy the tail of the original buffer into the current buffer
319 memmove (nl, nextline, buf + len - nextline);
320 len -= nextline - buf;
322 /* Continue the scan on the remaining lines in the buffer. */
325 /* Restore bufp to include all the remaining text. */
328 /* Reset the counter of what has been output this line. If wmargin
329 is 0, we want to avoid the lmargin getting added, so we set
330 point_col to a magic value of -1 in that case. */
331 fs->point_col = fs->wmargin ? fs->wmargin : -1;
335 /* Remember that we've scanned as far as the end of the buffer. */
336 fs->point_offs = fs->p - fs->buf;
339 /* Ensure that FS has space for AMOUNT more bytes in its buffer, either by
340 growing the buffer, or by flushing it. True is returned iff we succeed. */
342 __argp_fmtstream_ensure (struct argp_fmtstream *fs, size_t amount)
344 if ((size_t) (fs->end - fs->p) < amount)
348 /* Flush FS's buffer. */
349 __argp_fmtstream_update (fs);
352 __fxprintf (fs->stream, "%.*s", (int) (fs->p - fs->buf), fs->buf);
353 wrote = fs->p - fs->buf;
355 wrote = fwrite_unlocked (fs->buf, 1, fs->p - fs->buf, fs->stream);
357 if (wrote == fs->p - fs->buf)
365 fs->point_offs -= wrote;
366 memmove (fs->buf, fs->buf + wrote, fs->p - fs->buf);
370 if ((size_t) (fs->end - fs->buf) < amount)
371 /* Gotta grow the buffer. */
373 size_t old_size = fs->end - fs->buf;
374 size_t new_size = old_size + amount;
377 if (new_size < old_size || ! (new_buf = realloc (fs->buf, new_size)))
379 __set_errno (ENOMEM);
384 fs->end = new_buf + new_size;
393 __argp_fmtstream_printf (struct argp_fmtstream *fs, const char *fmt, ...)
397 size_t size_guess = PRINTF_SIZE_GUESS; /* How much space to reserve. */
403 if (! __argp_fmtstream_ensure (fs, size_guess))
406 va_start (args, fmt);
407 avail = fs->end - fs->p;
408 out = __vsnprintf (fs->p, avail, fmt, args);
410 if ((size_t) out >= avail)
411 size_guess = out + 1;
413 while ((size_t) out >= avail);
422 weak_alias (__argp_fmtstream_printf, argp_fmtstream_printf)
426 #endif /* !ARGP_FMTSTREAM_USE_LINEWRAP */