1 /* Word-wrapping and line-truncating streams
2 Copyright (C) 1997, 1998, 1999, 2001 Free Software Foundation, Inc.
3 This file is part of the GNU C Library.
4 Written by Miles Bader <miles@gnu.ai.mit.edu>.
5
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.
10
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.
15
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, write to the Free
18 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
19 02111-1307 USA. */
20
21 /* This package emulates glibc `line_wrap_stream' semantics for systems that
22 don't have that. */
23
24 #ifdef HAVE_CONFIG_H
25 #include <config.h>
26 #endif
27
28 #include <stdlib.h>
29 #include <string.h>
30 #include <errno.h>
31 #include <stdarg.h>
32 #include <ctype.h>
33
34 #include "argp-fmtstream.h"
35 #include "argp-namefrob.h"
36
37 #ifndef ARGP_FMTSTREAM_USE_LINEWRAP
38
39 #ifndef isblank
40 #define isblank(ch) ((ch)==' ' || (ch)=='\t')
41 #endif
42
43 #if defined _LIBC && defined USE_IN_LIBIO
44 # include <wchar.h>
45 # include <libio/libioP.h>
46 # define __vsnprintf(s, l, f, a) _IO_vsnprintf (s, l, f, a)
47 #endif
48
49 #define INIT_BUF_SIZE 200
50 #define PRINTF_SIZE_GUESS 150
51
52 /* Return an argp_fmtstream that outputs to STREAM, and which prefixes lines
53 written on it with LMARGIN spaces and limits them to RMARGIN columns
54 total. If WMARGIN >= 0, words that extend past RMARGIN are wrapped by
55 replacing the whitespace before them with a newline and WMARGIN spaces.
56 Otherwise, chars beyond RMARGIN are simply dropped until a newline.
57 Returns NULL if there was an error. */
58 argp_fmtstream_t
__argp_make_fmtstream(FILE * stream,size_t lmargin,size_t rmargin,ssize_t wmargin)59 __argp_make_fmtstream (FILE *stream,
60 size_t lmargin, size_t rmargin, ssize_t wmargin)
61 {
62 argp_fmtstream_t fs;
63
64 fs = (struct argp_fmtstream *) malloc (sizeof (struct argp_fmtstream));
65 if (fs != NULL)
66 {
67 fs->stream = stream;
68
69 fs->lmargin = lmargin;
70 fs->rmargin = rmargin;
71 fs->wmargin = wmargin;
72 fs->point_col = 0;
73 fs->point_offs = 0;
74
75 fs->buf = (char *) malloc (INIT_BUF_SIZE);
76 if (! fs->buf)
77 {
78 free (fs);
79 fs = 0;
80 }
81 else
82 {
83 fs->p = fs->buf;
84 fs->end = fs->buf + INIT_BUF_SIZE;
85 }
86 }
87
88 return fs;
89 }
90 #ifdef weak_alias
weak_alias(__argp_make_fmtstream,argp_make_fmtstream)91 weak_alias (__argp_make_fmtstream, argp_make_fmtstream)
92 #endif
93
94 /* Flush FS to its stream, and free it (but don't close the stream). */
95 void
96 __argp_fmtstream_free (argp_fmtstream_t fs)
97 {
98 __argp_fmtstream_update (fs);
99 if (fs->p > fs->buf)
100 {
101 #ifdef USE_IN_LIBIO
102 if (_IO_fwide (fs->stream, 0) > 0)
103 __fwprintf (fs->stream, L"%.*s", (int) (fs->p - fs->buf), fs->buf);
104 else
105 #endif
106 fwrite (fs->buf, 1, fs->p - fs->buf, fs->stream);
107 }
108 free (fs->buf);
109 free (fs);
110 }
111 #ifdef weak_alias
weak_alias(__argp_fmtstream_free,argp_fmtstream_free)112 weak_alias (__argp_fmtstream_free, argp_fmtstream_free)
113 #endif
114
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. */
117 void
118 __argp_fmtstream_update (argp_fmtstream_t fs)
119 {
120 char *buf, *nl;
121 size_t len;
122
123 /* Scan the buffer for newlines. */
124 buf = fs->buf + fs->point_offs;
125 while (buf < fs->p)
126 {
127 size_t r;
128
129 if (fs->point_col == 0 && fs->lmargin != 0)
130 {
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)
134 {
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. */
141 }
142 else
143 {
144 /* No buffer space for spaces. Must flush. */
145 size_t i;
146 for (i = 0; i < pad; i++)
147 {
148 #ifdef USE_IN_LIBIO
149 if (_IO_fwide (fs->stream, 0) > 0)
150 putwc_unlocked (L' ', fs->stream);
151 else
152 #endif
153 putc_unlocked (' ', fs->stream);
154 }
155 }
156 fs->point_col = pad;
157 }
158
159 len = fs->p - buf;
160 nl = memchr (buf, '\n', len);
161
162 if (fs->point_col < 0)
163 fs->point_col = 0;
164
165 if (!nl)
166 {
167 /* The buffer ends in a partial line. */
168
169 if (fs->point_col + len < fs->rmargin)
170 {
171 /* The remaining buffer text is a partial line and fits
172 within the maximum line width. Advance point for the
173 characters to be written and stop scanning. */
174 fs->point_col += len;
175 break;
176 }
177 else
178 /* Set the end-of-line pointer for the code below to
179 the end of the buffer. */
180 nl = fs->p;
181 }
182 else if (fs->point_col + (nl - buf) < (ssize_t) fs->rmargin)
183 {
184 /* The buffer contains a full line that fits within the maximum
185 line width. Reset point and scan the next line. */
186 fs->point_col = 0;
187 buf = nl + 1;
188 continue;
189 }
190
191 /* This line is too long. */
192 r = fs->rmargin - 1;
193
194 if (fs->wmargin < 0)
195 {
196 /* Truncate the line by overwriting the excess with the
197 newline and anything after it in the buffer. */
198 if (nl < fs->p)
199 {
200 memmove (buf + (r - fs->point_col), nl, fs->p - nl);
201 fs->p -= buf + (r - fs->point_col) - nl;
202 /* Reset point for the next line and start scanning it. */
203 fs->point_col = 0;
204 buf += r + 1; /* Skip full line plus \n. */
205 }
206 else
207 {
208 /* The buffer ends with a partial line that is beyond the
209 maximum line width. Advance point for the characters
210 written, and discard those past the max from the buffer. */
211 fs->point_col += len;
212 fs->p -= fs->point_col - r;
213 break;
214 }
215 }
216 else
217 {
218 /* Do word wrap. Go to the column just past the maximum line
219 width and scan back for the beginning of the word there.
220 Then insert a line break. */
221
222 char *p, *nextline;
223 int i;
224
225 p = buf + (r + 1 - fs->point_col);
226 while (p >= buf && !isblank (*p))
227 --p;
228 nextline = p + 1; /* This will begin the next line. */
229
230 if (nextline > buf)
231 {
232 /* Swallow separating blanks. */
233 if (p >= buf)
234 do
235 --p;
236 while (p >= buf && isblank (*p));
237 nl = p + 1; /* The newline will replace the first blank. */
238 }
239 else
240 {
241 /* A single word that is greater than the maximum line width.
242 Oh well. Put it on an overlong line by itself. */
243 p = buf + (r + 1 - fs->point_col);
244 /* Find the end of the long word. */
245 do
246 ++p;
247 while (p < nl && !isblank (*p));
248 if (p == nl)
249 {
250 /* It already ends a line. No fussing required. */
251 fs->point_col = 0;
252 buf = nl + 1;
253 continue;
254 }
255 /* We will move the newline to replace the first blank. */
256 nl = p;
257 /* Swallow separating blanks. */
258 do
259 ++p;
260 while (isblank (*p));
261 /* The next line will start here. */
262 nextline = p;
263 }
264
265 /* Note: There are a bunch of tests below for
266 NEXTLINE == BUF + LEN + 1; this case is where NL happens to fall
267 at the end of the buffer, and NEXTLINE is in fact empty (and so
268 we need not be careful to maintain its contents). */
269
270 if (nextline == buf + len + 1
271 ? fs->end - nl < fs->wmargin + 1
272 : nextline - (nl + 1) < fs->wmargin)
273 {
274 /* The margin needs more blanks than we removed. */
275 if (fs->end - fs->p > fs->wmargin + 1)
276 /* Make some space for them. */
277 {
278 size_t mv = fs->p - nextline;
279 memmove (nl + 1 + fs->wmargin, nextline, mv);
280 nextline = nl + 1 + fs->wmargin;
281 len = nextline + mv - buf;
282 *nl++ = '\n';
283 }
284 else
285 /* Output the first line so we can use the space. */
286 {
287 #ifdef USE_IN_LIBIO
288 if (_IO_fwide (fs->stream, 0) > 0)
289 __fwprintf (fs->stream, L"%.*s\n",
290 (int) (nl - fs->buf), fs->buf);
291 else
292 #endif
293 {
294 if (nl > fs->buf)
295 fwrite (fs->buf, 1, nl - fs->buf, fs->stream);
296 putc_unlocked ('\n', fs->stream);
297 }
298 len += buf - fs->buf;
299 nl = buf = fs->buf;
300 }
301 }
302 else
303 /* We can fit the newline and blanks in before
304 the next word. */
305 *nl++ = '\n';
306
307 if (nextline - nl >= fs->wmargin
308 || (nextline == buf + len + 1 && fs->end - nextline >= fs->wmargin))
309 /* Add blanks up to the wrap margin column. */
310 for (i = 0; i < fs->wmargin; ++i)
311 *nl++ = ' ';
312 else
313 for (i = 0; i < fs->wmargin; ++i)
314 #ifdef USE_IN_LIBIO
315 if (_IO_fwide (fs->stream, 0) > 0)
316 putwc_unlocked (L' ', fs->stream);
317 else
318 #endif
319 putc_unlocked (' ', fs->stream);
320
321 /* Copy the tail of the original buffer into the current buffer
322 position. */
323 if (nl < nextline)
324 memmove (nl, nextline, buf + len - nextline);
325 len -= nextline - buf;
326
327 /* Continue the scan on the remaining lines in the buffer. */
328 buf = nl;
329
330 /* Restore bufp to include all the remaining text. */
331 fs->p = nl + len;
332
333 /* Reset the counter of what has been output this line. If wmargin
334 is 0, we want to avoid the lmargin getting added, so we set
335 point_col to a magic value of -1 in that case. */
336 fs->point_col = fs->wmargin ? fs->wmargin : -1;
337 }
338 }
339
340 /* Remember that we've scanned as far as the end of the buffer. */
341 fs->point_offs = fs->p - fs->buf;
342 }
343
344 /* Ensure that FS has space for AMOUNT more bytes in its buffer, either by
345 growing the buffer, or by flushing it. True is returned iff we succeed. */
346 int
__argp_fmtstream_ensure(struct argp_fmtstream * fs,size_t amount)347 __argp_fmtstream_ensure (struct argp_fmtstream *fs, size_t amount)
348 {
349 if ((size_t) (fs->end - fs->p) < amount)
350 {
351 ssize_t wrote;
352
353 /* Flush FS's buffer. */
354 __argp_fmtstream_update (fs);
355
356 #ifdef USE_IN_LIBIO
357 if (_IO_fwide (fs->stream, 0) > 0)
358 {
359 __fwprintf (fs->stream, L"%.*s", (int) (fs->p - fs->buf), fs->buf);
360 wrote = fs->p - fs->buf;
361 }
362 else
363 #endif
364 wrote = fwrite (fs->buf, 1, fs->p - fs->buf, fs->stream);
365 if (wrote == fs->p - fs->buf)
366 {
367 fs->p = fs->buf;
368 fs->point_offs = 0;
369 }
370 else
371 {
372 fs->p -= wrote;
373 fs->point_offs -= wrote;
374 memmove (fs->buf, fs->buf + wrote, fs->p - fs->buf);
375 return 0;
376 }
377
378 if ((size_t) (fs->end - fs->buf) < amount)
379 /* Gotta grow the buffer. */
380 {
381 size_t new_size = fs->end - fs->buf + amount;
382 char *new_buf = realloc (fs->buf, new_size);
383
384 if (! new_buf)
385 {
386 __set_errno (ENOMEM);
387 return 0;
388 }
389
390 fs->buf = new_buf;
391 fs->end = new_buf + new_size;
392 fs->p = fs->buf;
393 }
394 }
395
396 return 1;
397 }
398
399 ssize_t
__argp_fmtstream_printf(struct argp_fmtstream * fs,const char * fmt,...)400 __argp_fmtstream_printf (struct argp_fmtstream *fs, const char *fmt, ...)
401 {
402 int out;
403 size_t avail;
404 size_t size_guess = PRINTF_SIZE_GUESS; /* How much space to reserve. */
405
406 do
407 {
408 va_list args;
409
410 if (! __argp_fmtstream_ensure (fs, size_guess))
411 return -1;
412
413 va_start (args, fmt);
414 avail = fs->end - fs->p;
415 out = __vsnprintf (fs->p, avail, fmt, args);
416 va_end (args);
417 if (out >= avail)
418 size_guess = out + 1;
419 }
420 while (out >= avail);
421
422 fs->p += out;
423
424 return out;
425 }
426 #ifdef weak_alias
427 weak_alias (__argp_fmtstream_printf, argp_fmtstream_printf)
428 #endif
429
430 #endif /* !ARGP_FMTSTREAM_USE_LINEWRAP */
431