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 # define __vsnprintf(s, l, f, a) _IO_vsnprintf (s, l, f, a)
47 #define INIT_BUF_SIZE 200
48 #define PRINTF_SIZE_GUESS 150
50 /* Return an argp_fmtstream that outputs to STREAM, and which prefixes lines
51 written on it with LMARGIN spaces and limits them to RMARGIN columns
52 total. If WMARGIN >= 0, words that extend past RMARGIN are wrapped by
53 replacing the whitespace before them with a newline and WMARGIN spaces.
54 Otherwise, chars beyond RMARGIN are simply dropped until a newline.
55 Returns NULL if there was an error. */
57 __argp_make_fmtstream (FILE *stream,
58 size_t lmargin, size_t rmargin, ssize_t wmargin)
60 argp_fmtstream_t fs = malloc (sizeof (struct argp_fmtstream));
65 fs->lmargin = lmargin;
66 fs->rmargin = rmargin;
67 fs->wmargin = wmargin;
71 fs->buf = malloc (INIT_BUF_SIZE);
80 fs->end = fs->buf + INIT_BUF_SIZE;
87 weak_alias (__argp_make_fmtstream, argp_make_fmtstream)
90 /* Flush FS to its stream, and free it (but don't close the stream). */
92 __argp_fmtstream_free (argp_fmtstream_t fs)
94 __argp_fmtstream_update (fs);
96 fwrite_unlocked (fs->buf, 1, fs->p - fs->buf, fs->stream);
101 weak_alias (__argp_fmtstream_free, argp_fmtstream_free)
104 /* Process FS's buffer so that line wrapping is done from POINT_OFFS to the
105 end of its buffer. This code is mostly from glibc stdio/linewrap.c. */
107 __argp_fmtstream_update (argp_fmtstream_t fs)
112 /* Scan the buffer for newlines. */
113 buf = fs->buf + fs->point_offs;
118 if (fs->point_col == 0 && fs->lmargin != 0)
120 /* We are starting a new line. Print spaces to the left margin. */
121 const size_t pad = fs->lmargin;
122 if (fs->p + pad < fs->end)
124 /* We can fit in them in the buffer by moving the
125 buffer text up and filling in the beginning. */
126 memmove (buf + pad, buf, fs->p - buf);
127 fs->p += pad; /* Compensate for bigger buffer. */
128 memset (buf, ' ', pad); /* Fill in the spaces. */
129 buf += pad; /* Don't bother searching them. */
133 /* No buffer space for spaces. Must flush. */
135 for (i = 0; i < pad; i++)
136 putc_unlocked (' ', fs->stream);
142 nl = memchr (buf, '\n', len);
144 if (fs->point_col < 0)
149 /* The buffer ends in a partial line. */
151 if (fs->point_col + len < fs->rmargin)
153 /* The remaining buffer text is a partial line and fits
154 within the maximum line width. Advance point for the
155 characters to be written and stop scanning. */
156 fs->point_col += len;
160 /* Set the end-of-line pointer for the code below to
161 the end of the buffer. */
164 else if (fs->point_col + (nl - buf) < (ssize_t) fs->rmargin)
166 /* The buffer contains a full line that fits within the maximum
167 line width. Reset point and scan the next line. */
173 /* This line is too long. */
178 /* Truncate the line by overwriting the excess with the
179 newline and anything after it in the buffer. */
182 memmove (buf + (r - fs->point_col), nl, fs->p - nl);
183 fs->p -= buf + (r - fs->point_col) - nl;
184 /* Reset point for the next line and start scanning it. */
186 buf += r + 1; /* Skip full line plus \n. */
190 /* The buffer ends with a partial line that is beyond the
191 maximum line width. Advance point for the characters
192 written, and discard those past the max from the buffer. */
193 fs->point_col += len;
194 fs->p -= fs->point_col - r;
200 /* Do word wrap. Go to the column just past the maximum line
201 width and scan back for the beginning of the word there.
202 Then insert a line break. */
207 p = buf + (r + 1 - fs->point_col);
208 while (p >= buf && !isblank (*p))
210 nextline = p + 1; /* This will begin the next line. */
214 /* Swallow separating blanks. */
218 while (p > buf && isblank (*p));
219 nl = p + 1; /* The newline will replace the first blank. */
223 /* A single word that is greater than the maximum line width.
224 Oh well. Put it on an overlong line by itself. */
225 p = buf + (r + 1 - fs->point_col);
226 /* Find the end of the long word. */
229 while (p < nl && !isblank (*p));
232 /* It already ends a line. No fussing required. */
237 /* We will move the newline to replace the first blank. */
239 /* Swallow separating blanks. */
242 while (isblank (*p));
243 /* The next line will start here. */
247 /* Note: There are a bunch of tests below for
248 NEXTLINE == BUF + LEN + 1; this case is where NL happens to fall
249 at the end of the buffer, and NEXTLINE is in fact empty (and so
250 we need not be careful to maintain its contents). */
252 if (nextline == buf + len + 1
253 ? fs->end - nl < fs->wmargin + 1
254 : nextline - (nl + 1) < fs->wmargin)
255 /* The margin needs more blanks than we removed. */
256 if (fs->end - fs->p > fs->wmargin + 1)
257 /* Make some space for them. */
259 size_t mv = fs->p - nextline;
260 memmove (nl + 1 + fs->wmargin, nextline, mv);
261 nextline = nl + 1 + fs->wmargin;
262 len = nextline + mv - buf;
266 /* Output the first line so we can use the space. */
269 fwrite_unlocked (fs->buf, 1, nl - fs->buf, fs->stream);
270 putc_unlocked ('\n', fs->stream);
271 len += buf - fs->buf;
275 /* We can fit the newline and blanks in before
279 if (nextline - nl >= fs->wmargin
280 || (nextline == buf + len + 1 && fs->end - nextline >= fs->wmargin))
281 /* Add blanks up to the wrap margin column. */
282 for (i = 0; i < fs->wmargin; ++i)
285 for (i = 0; i < fs->wmargin; ++i)
286 putc_unlocked (' ', fs->stream);
288 /* Copy the tail of the original buffer into the current buffer
291 memmove (nl, nextline, buf + len - nextline);
292 len -= nextline - buf;
294 /* Continue the scan on the remaining lines in the buffer. */
297 /* Restore bufp to include all the remaining text. */
300 /* Reset the counter of what has been output this line. If wmargin
301 is 0, we want to avoid the lmargin getting added, so we set
302 point_col to a magic value of -1 in that case. */
303 fs->point_col = fs->wmargin ? fs->wmargin : -1;
307 /* Remember that we've scanned as far as the end of the buffer. */
308 fs->point_offs = fs->p - fs->buf;
311 /* Ensure that FS has space for AMOUNT more bytes in its buffer, either by
312 growing the buffer, or by flushing it. True is returned iff we succeed. */
314 __argp_fmtstream_ensure (struct argp_fmtstream *fs, size_t amount)
316 if ((size_t) (fs->end - fs->p) < amount)
320 /* Flush FS's buffer. */
321 __argp_fmtstream_update (fs);
323 wrote = fwrite_unlocked (fs->buf, 1, fs->p - fs->buf, fs->stream);
324 if (wrote == fs->p - fs->buf)
332 fs->point_offs -= wrote;
333 memmove (fs->buf, fs->buf + wrote, fs->p - fs->buf);
337 if ((size_t) (fs->end - fs->buf) < amount)
338 /* Gotta grow the buffer. */
340 size_t new_size = fs->end - fs->buf + amount;
341 char *new_buf = realloc (fs->buf, new_size);
345 __set_errno (ENOMEM);
350 fs->end = new_buf + new_size;
359 __argp_fmtstream_printf (struct argp_fmtstream *fs, const char *fmt, ...)
362 size_t size_guess = PRINTF_SIZE_GUESS; /* How much space to reserve. */
368 if (! __argp_fmtstream_ensure (fs, size_guess))
370 size_guess += size_guess;
372 va_start (args, fmt);
373 out = __vsnprintf (fs->p, fs->end - fs->p, fmt, args);
383 weak_alias (__argp_fmtstream_printf, argp_fmtstream_printf)
386 #endif /* !ARGP_FMTSTREAM_USE_LINEWRAP */