1/* Copyright (C) 1994,1997,1999,2000,2001,2002 Free Software Foundation, Inc.
2   This file is part of the GNU C Library.
3
4   The GNU C Library is free software; you can redistribute it and/or
5   modify it under the terms of the GNU Lesser General Public
6   License as published by the Free Software Foundation; either
7   version 2.1 of the License, or (at your option) any later version.
8
9   The GNU C Library is distributed in the hope that it will be useful,
10   but WITHOUT ANY WARRANTY; without even the implied warranty of
11   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
12   Lesser General Public License for more details.
13
14   You should have received a copy of the GNU Lesser General Public
15   License along with the GNU C Library; if not, write to the Free
16   Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
17   02111-1307 USA.
18
19   As a special exception, if you link the code in this file with
20   files compiled with a GNU compiler to produce an executable,
21   that does not cause the resulting executable to be covered by
22   the GNU Lesser General Public License.  This exception does not
23   however invalidate any other reasons why the executable file
24   might be covered by the GNU Lesser General Public License.
25   This exception applies to code released by its copyright holders
26   in files containing the exception.  */
27
28#include "libioP.h"
29#include "strfile.h"
30
31
32typedef struct
33{
34  _IO_strfile f;
35  /* This is used for the characters which do not fit in the buffer
36     provided by the user.  */
37  char overflow_buf[64];
38} _IO_strnfile;
39
40
41static int _IO_strn_overflow __P ((_IO_FILE *fp, int c));
42
43static int
44_IO_strn_overflow (fp, c)
45     _IO_FILE *fp;
46     int c;
47{
48  /* When we come to here this means the user supplied buffer is
49     filled.  But since we must return the number of characters which
50     would have been written in total we must provide a buffer for
51     further use.  We can do this by writing on and on in the overflow
52     buffer in the _IO_strnfile structure.  */
53  _IO_strnfile *snf = (_IO_strnfile *) fp;
54
55  if (fp->_IO_buf_base != snf->overflow_buf)
56    {
57      /* Terminate the string.  We know that there is room for at
58	 least one more character since we initialized the stream with
59	 a size to make this possible.  */
60      *fp->_IO_write_ptr = '\0';
61
62      INTUSE(_IO_setb) (fp, snf->overflow_buf,
63			snf->overflow_buf + sizeof (snf->overflow_buf), 0);
64
65      fp->_IO_write_base = snf->overflow_buf;
66      fp->_IO_read_base = snf->overflow_buf;
67      fp->_IO_read_ptr = snf->overflow_buf;
68      fp->_IO_read_end = snf->overflow_buf + sizeof (snf->overflow_buf);
69    }
70
71  fp->_IO_write_ptr = snf->overflow_buf;
72  fp->_IO_write_end = snf->overflow_buf;
73
74  /* Since we are not really interested in storing the characters
75     which do not fit in the buffer we simply ignore it.  */
76  return c;
77}
78
79
80static struct _IO_jump_t _IO_strn_jumps =
81{
82  JUMP_INIT_DUMMY,
83  JUMP_INIT(finish, _IO_str_finish),
84  JUMP_INIT(overflow, _IO_strn_overflow),
85  JUMP_INIT(underflow, INTUSE(_IO_str_underflow)),
86  JUMP_INIT(uflow, INTUSE(_IO_default_uflow)),
87  JUMP_INIT(pbackfail, INTUSE(_IO_str_pbackfail)),
88  JUMP_INIT(xsputn, INTUSE(_IO_default_xsputn)),
89  JUMP_INIT(xsgetn, INTUSE(_IO_default_xsgetn)),
90  JUMP_INIT(seekoff, INTUSE(_IO_str_seekoff)),
91  JUMP_INIT(seekpos, _IO_default_seekpos),
92  JUMP_INIT(setbuf, _IO_default_setbuf),
93  JUMP_INIT(sync, _IO_default_sync),
94  JUMP_INIT(doallocate, INTUSE(_IO_default_doallocate)),
95  JUMP_INIT(read, _IO_default_read),
96  JUMP_INIT(write, _IO_default_write),
97  JUMP_INIT(seek, _IO_default_seek),
98  JUMP_INIT(close, _IO_default_close),
99  JUMP_INIT(stat, _IO_default_stat),
100  JUMP_INIT(showmanyc, _IO_default_showmanyc),
101  JUMP_INIT(imbue, _IO_default_imbue)
102};
103
104
105int
106_IO_vsnprintf (string, maxlen, format, args)
107     char *string;
108     _IO_size_t maxlen;
109     const char *format;
110     _IO_va_list args;
111{
112  _IO_strnfile sf;
113  int ret;
114#ifdef _IO_MTSAFE_IO
115  sf.f._sbf._f._lock = NULL;
116#endif
117
118  /* We need to handle the special case where MAXLEN is 0.  Use the
119     overflow buffer right from the start.  */
120  if (maxlen == 0)
121    {
122      string = sf.overflow_buf;
123      maxlen = sizeof (sf.overflow_buf);
124    }
125
126  _IO_no_init (&sf.f._sbf._f, _IO_USER_LOCK, -1, NULL, NULL);
127  _IO_JUMPS ((struct _IO_FILE_plus *) &sf.f._sbf) = &_IO_strn_jumps;
128  string[0] = '\0';
129  INTUSE(_IO_str_init_static) (&sf.f, string, maxlen - 1, string);
130  ret = INTUSE(_IO_vfprintf) ((_IO_FILE *) &sf.f._sbf, format, args);
131
132  if (sf.f._sbf._f._IO_buf_base != sf.overflow_buf)
133    *sf.f._sbf._f._IO_write_ptr = '\0';
134  return ret;
135}
136
137#ifdef weak_alias
138weak_alias (_IO_vsnprintf, __vsnprintf)
139weak_alias (_IO_vsnprintf, vsnprintf)
140#endif
141