summaryrefslogtreecommitdiff
path: root/strings/my_vsnprintf.c
blob: a57cc5b5ebe6d776bd17ee953a1fd0919e41e0b9 (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
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
/* 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; version 2 of the License.

   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>

/*
  Limited snprintf() implementations

  SYNOPSIS
    my_vsnprintf()
    to		Store result here
    n		Store up to n-1 characters, followed by an end 0
    fmt		printf format
    ap		Arguments

  IMPLEMENTION:
    Supports following formats:
    %#[l]d
    %#[l]u
    %#[l]x
    %#.#b 	Local format; note first # is ignored and second is REQUIRED
    %#.#s	Note first # is ignored
    
  RETURN
    length of result string
*/

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

  for (; *fmt ; fmt++)
  {
    if (*fmt != '%')
    {
      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= width= 0;
    pre_zero= have_long= 0;
    if (*fmt == '*')
    {
      fmt++;
      length= va_arg(ap, int);
    }
    else
      for (; my_isdigit(&my_charset_latin1, *fmt); fmt++)
      {
        length= length * 10 + (uint)(*fmt - '0');
        if (!length)
          pre_zero= 1;			/* first digit was 0 */
      }
    if (*fmt == '.')
    {
      fmt++;
      if (*fmt == '*')
      {
        fmt++;
        width= va_arg(ap, int);
      }
      else
        for (; my_isdigit(&my_charset_latin1, *fmt); fmt++)
          width= width * 10 + (uint)(*fmt - '0');
    }
    else
      width= ~0;
    if (*fmt == 'l')
    {
      fmt++;
      have_long= 1;
    }
    if (*fmt == 's')				/* String parameter */
    {
      reg2 char	*par = va_arg(ap, char *);
      size_t plen,left_len = (size_t) (end - to) + 1;
      if (!par) par = (char*)"(null)";
      plen= (uint) strnlen(par, width);
      if (left_len <= plen)
	plen = left_len - 1;
      to=strnmov(to,par,plen);
      continue;
    }
    else if (*fmt == 'b')				/* Buffer parameter */
    {
      char *par = va_arg(ap, char *);
      DBUG_ASSERT(to <= end);
      if (to + abs(width) + 1 > end)
        width= end - to - 1;  /* sign doesn't matter */
      memmove(to, par, abs(width));
      to+= width;
      continue;
    }
    else if (*fmt == 'd' || *fmt == 'u'|| *fmt== 'x')	/* Integer parameter */
    {
      register long larg;
      size_t res_length, to_length;
      char *store_start= to, *store_end;
      char buff[32];

      if ((to_length= (size_t) (end-to)) < 16 || length)
	store_start= buff;
      if (have_long)
        larg = va_arg(ap, long);
      else
        if (*fmt == 'd')
          larg = va_arg(ap, int);
        else
          larg= (long) (uint) va_arg(ap, int);
      if (*fmt == 'd')
	store_end= int10_to_str(larg, store_start, -10);
      else
        if (*fmt== 'u')
          store_end= int10_to_str(larg, store_start, 10);
        else
          store_end= int2str(larg, store_start, 16, 0);
      if ((res_length= (size_t) (store_end - store_start)) > to_length)
	break;					/* num doesn't fit in output */
      /* If %#d syntax was used, we have to pre-zero/pre-space the string */
      if (store_start == buff)
      {
	length= min(length, to_length);
	if (res_length < length)
	{
	  size_t diff= (length- res_length);
	  bfill(to, diff, pre_zero ? '0' : ' ');
	  to+= diff;
	}
	bmove(to, store_start, res_length);
      }
      to+= res_length;
      continue;
    }
    else if (*fmt == 'c')                       /* Character parameter */
    {
      register int larg;
      if (to == end)
        break;
      larg = va_arg(ap, int);
      *to++= (char) larg;
      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 (size_t) (to - start);
}


size_t 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;
}

#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 ((uchar) 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("Hex:   %lx  '%6lx'\n", 32, 65);
  my_printf("conn %ld to: '%-.64s' user: '%-.32s' host:\
 `%-.64s' (%-.64s)", 1, 0,0,0,0);
  return 0;
}
#endif