summaryrefslogtreecommitdiff
path: root/strings/my_vsnprintf.c
blob: deb9448857e3911c5ece56fb3d4a41530008f05e (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
/* Copyright (C) 2000 MySQL AB

   This program is free software; you can redistribute it and/or modify
   it under the terms of the GNU General Public License as published by
   the Free Software Foundation; either version 2 of the License, or
   (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA */

#include <my_global.h>
#include <m_string.h>
#include <stdarg.h>
#include <m_ctype.h>
#include <assert.h>

/*
  Limited snprintf() implementations

  IMPLEMENTION:
    Supports following formats:
    %#d
    %#u
    %#.#s	Note #.# is skiped

  RETURN
    length of result string
*/

int my_snprintf(char* to, size_t n, const char* fmt, ...)
{
  int result;
  va_list args;
  va_start(args,fmt);
  result= my_vsnprintf(to, n, fmt, args);
  va_end(args);
  return result;
}


int my_vsnprintf(char *to, size_t n, const char* fmt, va_list ap)
{
  char *start=to, *end=to+n-1;
  uint length, num_state, pre_zero;

  for (; *fmt ; fmt++)
  {
    if (fmt[0] != '%')
    {
      if (to == end)			/* End of buffer */
	break;
      *to++= *fmt;			/* Copy ordinary char */
      continue;
    }
    fmt++;					/* skip '%' */
    /* Read max fill size (only used with %d and %u) */
    if (*fmt == '-')
      fmt++;
    length= num_state= pre_zero= 0;
    for (;; fmt++)
    {
      if (my_isdigit(&my_charset_latin1,*fmt))
      {
	if (!num_state)
	{
	  length=length*10+ (uint) (*fmt-'0');
	  if (!length)
	    pre_zero= 1;			/* first digit was 0 */
	}
	continue;
      }
      if (*fmt != '.' || num_state)
	break;
      num_state= 1;
    }
    if (*fmt == 'l')
      fmt++;
    if (*fmt == 's')				/* String parameter */
    {
      reg2 char	*par = va_arg(ap, char *);
      uint plen,left_len = (uint)(end-to)+1;
      if (!par) par = (char*)"(null)";
      plen = (uint) strlen(par);
      if (left_len <= plen)
	plen = left_len - 1;
      to=strnmov(to,par,plen);
      continue;
    }
    else if (*fmt == 'd' || *fmt == 'u')	/* Integer parameter */
    {
      register int iarg;
      char *to_start= to;
      if ((uint) (end-to) < max(16,length))
	break;
      iarg = va_arg(ap, int);
      if (*fmt == 'd')
	to=int10_to_str((long) iarg,to, -10);
      else
	to=int10_to_str((long) (uint) iarg,to,10);
      /* If %#d syntax was used, we have to pre-zero/pre-space the string */
      if (length)
      {
	uint res_length= (uint) (to - to_start);
	if (res_length < length)
	{
	  uint diff= (length- res_length);
	  bmove_upp(to+diff, to, res_length);
	  bfill(to-res_length, diff, pre_zero ? '0' : ' ');
	  to+= diff;
	}
      }
      continue;
    }
    /* We come here on '%%', unknown code or too long parameter */
    if (to == end)
      break;
    *to++='%';				/* % used as % or unknown code */
  }
  DBUG_ASSERT(to <= end);
  *to='\0';				/* End of errmessage */
  return (uint) (to - start);
}


#ifdef MAIN
#define OVERRUN_SENTRY  250
static void my_printf(const char * fmt, ...)
{
  char buf[33];
  int n;
  va_list ar;
  va_start(ar, fmt);
  buf[sizeof(buf)-1]=OVERRUN_SENTRY;
  n = my_vsnprintf(buf, sizeof(buf)-1,fmt, ar);
  printf(buf);
  printf("n=%d, strlen=%d\n", n, strlen(buf));
  if (buf[sizeof(buf)-1] != OVERRUN_SENTRY)
  {
    fprintf(stderr, "Buffer overrun\n");
    abort();
  }
  va_end(ar);
}


int main()
{

  my_printf("Hello\n");
  my_printf("Hello int, %d\n", 1);
  my_printf("Hello string '%s'\n", "I am a string");
  my_printf("Hello hack hack hack hack hack hack hack %d\n", 1);
  my_printf("Hello %d hack  %d\n", 1, 4);
  my_printf("Hello %d hack hack hack hack hack %d\n", 1, 4);
  my_printf("Hello '%s' hhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhhh\n", "hack");
  my_printf("Hello hhhhhhhhhhhhhh %d sssssssssssssss\n", 1);
  my_printf("Hello  %u\n", 1);
  my_printf("conn %ld to: '%-.64s' user: '%-.32s' host:\
 `%-.64s' (%-.64s)", 1, 0,0,0,0);
  return 0;
}
#endif