1/* Word-wrapping and line-truncating streams
2   Copyright (C) 1997-1999,2001,2002,2003,2005 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   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)
9   any later version.
10
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.
15
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., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301, USA. */
19
20/* This package emulates glibc `line_wrap_stream' semantics for systems that
21   don't have that.  */
22
23#ifdef HAVE_CONFIG_H
24# include <config.h>
25#endif
26
27#include <stdlib.h>
28#include <string.h>
29#include <errno.h>
30#include <stdarg.h>
31#include <ctype.h>
32
33#include "argp-fmtstream.h"
34#include "argp-namefrob.h"
35
36#ifndef ARGP_FMTSTREAM_USE_LINEWRAP
37
38#ifndef isblank
39#define isblank(ch) ((ch)==' ' || (ch)=='\t')
40#endif
41
42#if defined _LIBC && defined USE_IN_LIBIO
43# include <wchar.h>
44# include <libio/libioP.h>
45# define __vsnprintf(s, l, f, a) _IO_vsnprintf (s, l, f, a)
46#endif
47
48#define INIT_BUF_SIZE 200
49#define PRINTF_SIZE_GUESS 150
50
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.  */
57argp_fmtstream_t
58__argp_make_fmtstream (FILE *stream,
59		       size_t lmargin, size_t rmargin, ssize_t wmargin)
60{
61  argp_fmtstream_t fs;
62
63  fs = (struct argp_fmtstream *) malloc (sizeof (struct argp_fmtstream));
64  if (fs != NULL)
65    {
66      fs->stream = stream;
67
68      fs->lmargin = lmargin;
69      fs->rmargin = rmargin;
70      fs->wmargin = wmargin;
71      fs->point_col = 0;
72      fs->point_offs = 0;
73
74      fs->buf = (char *) malloc (INIT_BUF_SIZE);
75      if (! fs->buf)
76	{
77	  free (fs);
78	  fs = 0;
79	}
80      else
81	{
82	  fs->p = fs->buf;
83	  fs->end = fs->buf + INIT_BUF_SIZE;
84	}
85    }
86
87  return fs;
88}
89#if 0
90/* Not exported.  */
91#ifdef weak_alias
92weak_alias (__argp_make_fmtstream, argp_make_fmtstream)
93#endif
94#endif
95
96/* Flush FS to its stream, and free it (but don't close the stream).  */
97void
98__argp_fmtstream_free (argp_fmtstream_t fs)
99{
100  __argp_fmtstream_update (fs);
101  if (fs->p > fs->buf)
102    {
103#ifdef USE_IN_LIBIO
104      __fxprintf (fs->stream, "%.*s", (int) (fs->p - fs->buf), fs->buf);
105#else
106      fwrite_unlocked (fs->buf, 1, fs->p - fs->buf, fs->stream);
107#endif
108    }
109  free (fs->buf);
110  free (fs);
111}
112#if 0
113/* Not exported.  */
114#ifdef weak_alias
115weak_alias (__argp_fmtstream_free, argp_fmtstream_free)
116#endif
117#endif
118
119/* Process FS's buffer so that line wrapping is done from POINT_OFFS to the
120   end of its buffer.  This code is mostly from glibc stdio/linewrap.c.  */
121void
122__argp_fmtstream_update (argp_fmtstream_t fs)
123{
124  char *buf, *nl;
125  size_t len;
126
127  /* Scan the buffer for newlines.  */
128  buf = fs->buf + fs->point_offs;
129  while (buf < fs->p)
130    {
131      size_t r;
132
133      if (fs->point_col == 0 && fs->lmargin != 0)
134	{
135	  /* We are starting a new line.  Print spaces to the left margin.  */
136	  const size_t pad = fs->lmargin;
137	  if (fs->p + pad < fs->end)
138	    {
139	      /* We can fit in them in the buffer by moving the
140		 buffer text up and filling in the beginning.  */
141	      memmove (buf + pad, buf, fs->p - buf);
142	      fs->p += pad; /* Compensate for bigger buffer. */
143	      memset (buf, ' ', pad); /* Fill in the spaces.  */
144	      buf += pad; /* Don't bother searching them.  */
145	    }
146	  else
147	    {
148	      /* No buffer space for spaces.  Must flush.  */
149	      size_t i;
150	      for (i = 0; i < pad; i++)
151		{
152#ifdef USE_IN_LIBIO
153		  if (_IO_fwide (fs->stream, 0) > 0)
154		    putwc_unlocked (L' ', fs->stream);
155		  else
156#endif
157		    putc_unlocked (' ', fs->stream);
158		}
159	    }
160	  fs->point_col = pad;
161	}
162
163      len = fs->p - buf;
164      nl = memchr (buf, '\n', len);
165
166      if (fs->point_col < 0)
167	fs->point_col = 0;
168
169      if (!nl)
170	{
171	  /* The buffer ends in a partial line.  */
172
173	  if (fs->point_col + len < fs->rmargin)
174	    {
175	      /* The remaining buffer text is a partial line and fits
176		 within the maximum line width.  Advance point for the
177		 characters to be written and stop scanning.  */
178	      fs->point_col += len;
179	      break;
180	    }
181	  else
182	    /* Set the end-of-line pointer for the code below to
183	       the end of the buffer.  */
184	    nl = fs->p;
185	}
186      else if (fs->point_col + (nl - buf) < (ssize_t) fs->rmargin)
187	{
188	  /* The buffer contains a full line that fits within the maximum
189	     line width.  Reset point and scan the next line.  */
190	  fs->point_col = 0;
191	  buf = nl + 1;
192	  continue;
193	}
194
195      /* This line is too long.  */
196      r = fs->rmargin - 1;
197
198      if (fs->wmargin < 0)
199	{
200	  /* Truncate the line by overwriting the excess with the
201	     newline and anything after it in the buffer.  */
202	  if (nl < fs->p)
203	    {
204	      memmove (buf + (r - fs->point_col), nl, fs->p - nl);
205	      fs->p -= buf + (r - fs->point_col) - nl;
206	      /* Reset point for the next line and start scanning it.  */
207	      fs->point_col = 0;
208	      buf += r + 1; /* Skip full line plus \n. */
209	    }
210	  else
211	    {
212	      /* The buffer ends with a partial line that is beyond the
213		 maximum line width.  Advance point for the characters
214		 written, and discard those past the max from the buffer.  */
215	      fs->point_col += len;
216	      fs->p -= fs->point_col - r;
217	      break;
218	    }
219	}
220      else
221	{
222	  /* Do word wrap.  Go to the column just past the maximum line
223	     width and scan back for the beginning of the word there.
224	     Then insert a line break.  */
225
226	  char *p, *nextline;
227	  int i;
228
229	  p = buf + (r + 1 - fs->point_col);
230	  while (p >= buf && !isblank (*p))
231	    --p;
232	  nextline = p + 1;	/* This will begin the next line.  */
233
234	  if (nextline > buf)
235	    {
236	      /* Swallow separating blanks.  */
237	      if (p >= buf)
238		do
239		  --p;
240		while (p >= buf && isblank (*p));
241	      nl = p + 1;	/* The newline will replace the first blank. */
242	    }
243	  else
244	    {
245	      /* A single word that is greater than the maximum line width.
246		 Oh well.  Put it on an overlong line by itself.  */
247	      p = buf + (r + 1 - fs->point_col);
248	      /* Find the end of the long word.  */
249	      if (p < nl)
250		do
251		  ++p;
252		while (p < nl && !isblank (*p));
253	      if (p == nl)
254		{
255		  /* It already ends a line.  No fussing required.  */
256		  fs->point_col = 0;
257		  buf = nl + 1;
258		  continue;
259		}
260	      /* We will move the newline to replace the first blank.  */
261	      nl = p;
262	      /* Swallow separating blanks.  */
263	      do
264		++p;
265	      while (isblank (*p));
266	      /* The next line will start here.  */
267	      nextline = p;
268	    }
269
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).  */
274
275	  if ((nextline == buf + len + 1
276	       ? fs->end - nl < fs->wmargin + 1
277	       : nextline - (nl + 1) < fs->wmargin)
278	      && fs->p > nextline)
279	    {
280	      /* The margin needs more blanks than we removed.  */
281	      if (fs->end - fs->p > fs->wmargin + 1)
282		/* Make some space for them.  */
283		{
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;
288		  *nl++ = '\n';
289		}
290	      else
291		/* Output the first line so we can use the space.  */
292		{
293#ifdef _LIBC
294		  __fxprintf (fs->stream, "%.*s\n",
295			      (int) (nl - fs->buf), fs->buf);
296#else
297		  if (nl > fs->buf)
298		    fwrite_unlocked (fs->buf, 1, nl - fs->buf, fs->stream);
299		  putc_unlocked ('\n', fs->stream);
300#endif
301
302		  len += buf - fs->buf;
303		  nl = buf = fs->buf;
304		}
305	    }
306	  else
307	    /* We can fit the newline and blanks in before
308	       the next word.  */
309	    *nl++ = '\n';
310
311	  if (nextline - nl >= fs->wmargin
312	      || (nextline == buf + len + 1 && fs->end - nextline >= fs->wmargin))
313	    /* Add blanks up to the wrap margin column.  */
314	    for (i = 0; i < fs->wmargin; ++i)
315	      *nl++ = ' ';
316	  else
317	    for (i = 0; i < fs->wmargin; ++i)
318#ifdef USE_IN_LIBIO
319	      if (_IO_fwide (fs->stream, 0) > 0)
320		putwc_unlocked (L' ', fs->stream);
321	      else
322#endif
323		putc_unlocked (' ', fs->stream);
324
325	  /* Copy the tail of the original buffer into the current buffer
326	     position.  */
327	  if (nl < nextline)
328	    memmove (nl, nextline, buf + len - nextline);
329	  len -= nextline - buf;
330
331	  /* Continue the scan on the remaining lines in the buffer.  */
332	  buf = nl;
333
334	  /* Restore bufp to include all the remaining text.  */
335	  fs->p = nl + len;
336
337	  /* Reset the counter of what has been output this line.  If wmargin
338	     is 0, we want to avoid the lmargin getting added, so we set
339	     point_col to a magic value of -1 in that case.  */
340	  fs->point_col = fs->wmargin ? fs->wmargin : -1;
341	}
342    }
343
344  /* Remember that we've scanned as far as the end of the buffer.  */
345  fs->point_offs = fs->p - fs->buf;
346}
347
348/* Ensure that FS has space for AMOUNT more bytes in its buffer, either by
349   growing the buffer, or by flushing it.  True is returned iff we succeed. */
350int
351__argp_fmtstream_ensure (struct argp_fmtstream *fs, size_t amount)
352{
353  if ((size_t) (fs->end - fs->p) < amount)
354    {
355      ssize_t wrote;
356
357      /* Flush FS's buffer.  */
358      __argp_fmtstream_update (fs);
359
360#ifdef _LIBC
361      __fxprintf (fs->stream, "%.*s", (int) (fs->p - fs->buf), fs->buf);
362      wrote = fs->p - fs->buf;
363#else
364      wrote = fwrite_unlocked (fs->buf, 1, fs->p - fs->buf, fs->stream);
365#endif
366      if (wrote == fs->p - fs->buf)
367	{
368	  fs->p = fs->buf;
369	  fs->point_offs = 0;
370	}
371      else
372	{
373	  fs->p -= wrote;
374	  fs->point_offs -= wrote;
375	  memmove (fs->buf, fs->buf + wrote, fs->p - fs->buf);
376	  return 0;
377	}
378
379      if ((size_t) (fs->end - fs->buf) < amount)
380	/* Gotta grow the buffer.  */
381	{
382	  size_t old_size = fs->end - fs->buf;
383	  size_t new_size = old_size + amount;
384	  char *new_buf;
385
386	  if (new_size < old_size || ! (new_buf = realloc (fs->buf, new_size)))
387	    {
388	      __set_errno (ENOMEM);
389	      return 0;
390	    }
391
392	  fs->buf = new_buf;
393	  fs->end = new_buf + new_size;
394	  fs->p = fs->buf;
395	}
396    }
397
398  return 1;
399}
400
401ssize_t
402__argp_fmtstream_printf (struct argp_fmtstream *fs, const char *fmt, ...)
403{
404  int out;
405  size_t avail;
406  size_t size_guess = PRINTF_SIZE_GUESS; /* How much space to reserve. */
407
408  do
409    {
410      va_list args;
411
412      if (! __argp_fmtstream_ensure (fs, size_guess))
413	return -1;
414
415      va_start (args, fmt);
416      avail = fs->end - fs->p;
417      out = __vsnprintf (fs->p, avail, fmt, args);
418      va_end (args);
419      if ((size_t) out >= avail)
420	size_guess = out + 1;
421    }
422  while ((size_t) out >= avail);
423
424  fs->p += out;
425
426  return out;
427}
428#if 0
429/* Not exported.  */
430#ifdef weak_alias
431weak_alias (__argp_fmtstream_printf, argp_fmtstream_printf)
432#endif
433#endif
434
435#endif /* !ARGP_FMTSTREAM_USE_LINEWRAP */
436