1 /* Word-wrapping and line-truncating streams
2 Copyright (C) 1997 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 #define INIT_BUF_SIZE 200
44 #define PRINTF_SIZE_GUESS 150
46 /* Return an argp_fmtstream that outputs to STREAM, and which prefixes lines
47 written on it with LMARGIN spaces and limits them to RMARGIN columns
48 total. If WMARGIN >= 0, words that extend past RMARGIN are wrapped by
49 replacing the whitespace before them with a newline and WMARGIN spaces.
50 Otherwise, chars beyond RMARGIN are simply dropped until a newline.
51 Returns NULL if there was an error. */
53 __argp_make_fmtstream (FILE *stream,
54 size_t lmargin, size_t rmargin, ssize_t wmargin)
56 argp_fmtstream_t fs = malloc (sizeof (struct argp_fmtstream));
61 fs->lmargin = lmargin;
62 fs->rmargin = rmargin;
63 fs->wmargin = wmargin;
67 fs->buf = malloc (INIT_BUF_SIZE);
76 fs->end = fs->buf + INIT_BUF_SIZE;
83 weak_alias (__argp_make_fmtstream, argp_make_fmtstream)
86 /* Flush FS to its stream, and free it (but don't close the stream). */
88 __argp_fmtstream_free (argp_fmtstream_t fs)
90 __argp_fmtstream_update (fs);
92 fwrite (fs->buf, 1, fs->p - fs->buf, fs->stream);
97 weak_alias (__argp_fmtstream_free, argp_fmtstream_free)
100 /* Process FS's buffer so that line wrapping is done from POINT_OFFS to the
101 end of its buffer. This code is mostly from glibc stdio/linewrap.c. */
103 __argp_fmtstream_update (argp_fmtstream_t fs)
108 /* Scan the buffer for newlines. */
109 buf = fs->buf + fs->point_offs;
114 if (fs->point_col == 0 && fs->lmargin != 0)
116 /* We are starting a new line. Print spaces to the left margin. */
117 const size_t pad = fs->lmargin;
118 if (fs->p + pad < fs->end)
120 /* We can fit in them in the buffer by moving the
121 buffer text up and filling in the beginning. */
122 memmove (buf + pad, buf, fs->p - buf);
123 fs->p += pad; /* Compensate for bigger buffer. */
124 memset (buf, ' ', pad); /* Fill in the spaces. */
125 buf += pad; /* Don't bother searching them. */
129 /* No buffer space for spaces. Must flush. */
131 for (i = 0; i < pad; i++)
132 putc (' ', fs->stream);
138 nl = memchr (buf, '\n', len);
140 if (fs->point_col < 0)
145 /* The buffer ends in a partial line. */
147 if (fs->point_col + len < fs->rmargin)
149 /* The remaining buffer text is a partial line and fits
150 within the maximum line width. Advance point for the
151 characters to be written and stop scanning. */
152 fs->point_col += len;
156 /* Set the end-of-line pointer for the code below to
157 the end of the buffer. */
160 else if (fs->point_col + (nl - buf) < fs->rmargin)
162 /* The buffer contains a full line that fits within the maximum
163 line width. Reset point and scan the next line. */
169 /* This line is too long. */
174 /* Truncate the line by overwriting the excess with the
175 newline and anything after it in the buffer. */
178 memmove (buf + (r - fs->point_col), nl, fs->p - nl);
179 fs->p -= buf + (r - fs->point_col) - nl;
180 /* Reset point for the next line and start scanning it. */
182 buf += r + 1; /* Skip full line plus \n. */
186 /* The buffer ends with a partial line that is beyond the
187 maximum line width. Advance point for the characters
188 written, and discard those past the max from the buffer. */
189 fs->point_col += len;
190 fs->p -= fs->point_col - r;
196 /* Do word wrap. Go to the column just past the maximum line
197 width and scan back for the beginning of the word there.
198 Then insert a line break. */
203 p = buf + (r + 1 - fs->point_col);
204 while (p >= buf && !isblank (*p))
206 nextline = p + 1; /* This will begin the next line. */
210 /* Swallow separating blanks. */
214 while (p > buf && isblank (*p));
215 nl = p + 1; /* The newline will replace the first blank. */
219 /* A single word that is greater than the maximum line width.
220 Oh well. Put it on an overlong line by itself. */
221 p = buf + (r + 1 - fs->point_col);
222 /* Find the end of the long word. */
225 while (p < nl && !isblank (*p));
228 /* It already ends a line. No fussing required. */
233 /* We will move the newline to replace the first blank. */
235 /* Swallow separating blanks. */
238 while (isblank (*p));
239 /* The next line will start here. */
243 if (nextline - (nl + 1) < fs->wmargin)
244 /* The margin needs more blanks than we removed. */
245 if (fs->end - fs->p > fs->wmargin + 1)
246 /* Make some space for them. */
248 size_t mv = fs->p - nextline;
249 memmove (nl + 1 + fs->wmargin, nextline, mv);
250 nextline = nl + 1 + fs->wmargin;
251 len = nextline + mv - buf;
255 /* Output the first line so we can use the space. */
258 fwrite (fs->buf, 1, nl - fs->buf, fs->stream);
259 putc ('\n', fs->stream);
260 len += buf - fs->buf;
264 /* We can fit the newline and blanks in before
268 if (nextline - nl >= fs->wmargin)
269 /* Add blanks up to the wrap margin column. */
270 for (i = 0; i < fs->wmargin; ++i)
273 for (i = 0; i < fs->wmargin; ++i)
274 putc (' ', fs->stream);
276 /* Copy the tail of the original buffer into the current buffer
279 memmove (nl, nextline, buf + len - nextline);
280 len -= nextline - buf;
282 /* Continue the scan on the remaining lines in the buffer. */
285 /* Restore bufp to include all the remaining text. */
288 /* Reset the counter of what has been output this line. If wmargin
289 is 0, we want to avoid the lmargin getting added, so we set
290 point_col to a magic value of -1 in that case. */
291 fs->point_col = fs->wmargin ? fs->wmargin : -1;
295 /* Remember that we've scanned as far as the end of the buffer. */
296 fs->point_offs = fs->p - fs->buf;
299 /* Ensure that FS has space for AMOUNT more bytes in its buffer, either by
300 growing the buffer, or by flushing it. True is returned iff we succeed. */
302 __argp_fmtstream_ensure (struct argp_fmtstream *fs, size_t amount)
304 if (fs->end - fs->p < amount)
308 /* Flush FS's buffer. */
309 __argp_fmtstream_update (fs);
311 wrote = fwrite (fs->buf, 1, fs->p - fs->buf, fs->stream);
312 if (wrote == fs->p - fs->buf)
320 fs->point_offs -= wrote;
321 memmove (fs->buf, fs->buf + wrote, fs->p - fs->buf);
325 if (fs->end - fs->buf < amount)
326 /* Gotta grow the buffer. */
328 size_t new_size = fs->end - fs->buf + amount;
329 char *new_buf = realloc (fs->buf, new_size);
333 __set_errno (ENOMEM);
338 fs->end = new_buf + new_size;
347 __argp_fmtstream_printf (struct argp_fmtstream *fs, const char *fmt, ...)
350 size_t size_guess = PRINTF_SIZE_GUESS; /* How much space to reserve. */
356 if (! __argp_fmtstream_ensure (fs, size_guess))
358 size_guess += size_guess;
360 va_start (args, fmt);
361 out = __vsnprintf (fs->p, fs->end - fs->p, fmt, args);
371 weak_alias (__argp_fmtstream_printf, argp_fmtstream_printf)
374 #endif /* !ARGP_FMTSTREAM_USE_LINEWRAP */