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