Use INTERNAL_SYSCALL.
[glibc.git] / libio / vsnprintf.c
blob8a3afc46bda38ef556f1b3eee27f2899d1cd73ff
1 /* Copyright (C) 1994,1997,1999,2000,2001,2002 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
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.
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.
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.
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. */
28 #include "libioP.h"
29 #include "strfile.h"
32 typedef struct
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;
41 static int _IO_strn_overflow __P ((_IO_FILE *fp, int c));
43 static int
44 _IO_strn_overflow (fp, c)
45 _IO_FILE *fp;
46 int c;
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;
55 if (fp->_IO_buf_base != snf->overflow_buf)
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';
62 INTUSE(_IO_setb) (fp, snf->overflow_buf,
63 snf->overflow_buf + sizeof (snf->overflow_buf), 0);
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);
71 fp->_IO_write_ptr = snf->overflow_buf;
72 fp->_IO_write_end = snf->overflow_buf;
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;
80 static struct _IO_jump_t _IO_strn_jumps =
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)
106 _IO_vsnprintf (string, maxlen, format, args)
107 char *string;
108 _IO_size_t maxlen;
109 const char *format;
110 _IO_va_list args;
112 _IO_strnfile sf;
113 int ret;
114 #ifdef _IO_MTSAFE_IO
115 sf.f._sbf._f._lock = NULL;
116 #endif
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)
122 string = sf.overflow_buf;
123 maxlen = sizeof (sf.overflow_buf);
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);
132 if (sf.f._sbf._f._IO_buf_base != sf.overflow_buf)
133 *sf.f._sbf._f._IO_write_ptr = '\0';
134 return ret;
137 #ifdef weak_alias
138 weak_alias (_IO_vsnprintf, __vsnprintf)
139 weak_alias (_IO_vsnprintf, vsnprintf)
140 #endif