Subversion Repositories HelenOS

Rev

Rev 2208 | Go to most recent revision | Details | Compare with Previous | Last modification | View Log | RSS feed

Rev Author Line No. Line
1271 cejka 1
/*
2071 jermar 2
 * Copyright (c) 2006 Josef Cejka
1271 cejka 3
 * All rights reserved.
4
 *
5
 * Redistribution and use in source and binary forms, with or without
6
 * modification, are permitted provided that the following conditions
7
 * are met:
8
 *
9
 * - Redistributions of source code must retain the above copyright
10
 *   notice, this list of conditions and the following disclaimer.
11
 * - Redistributions in binary form must reproduce the above copyright
12
 *   notice, this list of conditions and the following disclaimer in the
13
 *   documentation and/or other materials provided with the distribution.
14
 * - The name of the author may not be used to endorse or promote products
15
 *   derived from this software without specific prior written permission.
16
 *
17
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
18
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
23
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
25
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
26
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27
 */
28
 
1888 jermar 29
/** @addtogroup generic
1702 cejka 30
 * @{
31
 */
32
/** @file
33
 */
34
 
1271 cejka 35
#include <print.h>
36
#include <printf/printf_core.h>
37
#include <memstr.h>
38
 
39
struct vsnprintf_data {
40
    size_t size; /* total space for string */
41
    size_t len; /* count of currently used characters */
42
    char *string; /* destination string */
43
};
44
 
45
/** Write string to given buffer.
1288 jermar 46
 * Write at most data->size characters including trailing zero. According to C99, snprintf() has to return number
1271 cejka 47
 * of characters that would have been written if enough space had been available. Hence the return value is not
1288 jermar 48
 * number of really printed characters but size of the input string. Number of really used characters
1271 cejka 49
 * is stored in data->len.
50
 * @param str source string to print
51
 * @param count size of source string
52
 * @param data structure with destination string, counter of used space and total string size.
53
 * @return number of characters to print (not characters really printed!)
54
 */
2208 decky 55
static int vsnprintf_write(const char *str, size_t count, struct vsnprintf_data *data)
1271 cejka 56
{
1604 cejka 57
    size_t i;
1271 cejka 58
    i = data->size - data->len;
59
 
1605 cejka 60
    if (i == 0) {
61
        return count;
1271 cejka 62
    }
63
 
1604 cejka 64
    if (i == 1) {
65
        /* We have only one free byte left in buffer => write there trailing zero */
66
        data->string[data->size - 1] = 0;
67
        data->len = data->size;
1605 cejka 68
        return count;
1604 cejka 69
    }
70
 
71
    if (i <= count) {
72
        /* We have not enought space for whole string with the trailing zero => print only a part of string */
73
            memcpy((void *)(data->string + data->len), (void *)str, i - 1);
74
            data->string[data->size - 1] = 0;
75
            data->len = data->size;
1605 cejka 76
            return count;
1604 cejka 77
    }
78
 
79
    /* Buffer is big enought to print whole string */
80
    memcpy((void *)(data->string + data->len), (void *)str, count);
81
    data->len += count;
82
    /* Put trailing zero at end, but not count it into data->len so it could be rewritten next time */
83
    data->string[data->len] = 0;
84
 
1271 cejka 85
    return count;  
86
}
87
 
88
int vsnprintf(char *str, size_t size, const char *fmt, va_list ap)
89
{
90
    struct vsnprintf_data data = {size, 0, str};
91
    struct printf_spec ps = {(int(*)(void *, size_t, void *))vsnprintf_write, &data};
92
 
93
    /* Print 0 at end of string - fix the case that nothing will be printed */
94
    if (size > 0)
95
        str[0] = 0;
96
 
97
    /* vsnprintf_write ensures that str will be terminated by zero. */
98
    return printf_core(fmt, &ps, ap);
99
}
1702 cejka 100
 
1888 jermar 101
/** @}
1702 cejka 102
 */