Subversion Repositories HelenOS

Rev

Rev 3343 | Details | Compare with Previous | Last modification | View Log | RSS feed

Rev Author Line No. Line
1234 cejka 1 
/*
2071 jermar 2 
 * Copyright (c) 2006 Josef Cejka
1234 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 
 
1866 jermar 29 
/** @addtogroup libc
1653 cejka 30 
 * @{
31 
 */
32 
/** @file
33 
 */
34 
 
1234 cejka 35 
#include <stdarg.h>
36 
#include <stdio.h>
37 
#include <string.h>
38 
#include <io/printf_core.h>
39 
 
40 
struct vsnprintf_data {
3397 rimsky 41 
    size_t size;    /* total space for string */
42 
    size_t len; /* count of currently used characters */
43 
    char *string;   /* destination string */
1234 cejka 44 
};
45 
 
46 
/** Write string to given buffer.
3397 rimsky 47 
 * Write at most data->size characters including trailing zero. According to C99
48 
 * has snprintf to return number of characters that would have been written if
49 
 * enough space had been available. Hence the return value is not number of
50 
 * really printed characters but size of input string. Number of really used
51 
 * characters is stored in data->len.
52 
 *
53 
 * @param str       Source string to print.
54 
 * @param count     Size of the source string.
55 
 * @param data      Structure with destination string, counter of used space
56 
 *          and total string size.
57 
 * @return      Number of characters to print (not characters really
58 
 *          printed!)
1234 cejka 59 
 */
3397 rimsky 60 
static int
61 
vsnprintf_write(const char *str, size_t count, struct vsnprintf_data *data)
1234 cejka 62 
{
1617 cejka 63 
    size_t i;
1234 cejka 64 
    i = data->size - data->len;
65 
 
1617 cejka 66 
    if (i == 0) {
67 
        return count;
1234 cejka 68 
    }
69 
 
1617 cejka 70 
    if (i == 1) {
3397 rimsky 71 
        /*
72 
         * We have only one free byte left in buffer => write there
73 
         * trailing zero.
74 
         */
1617 cejka 75 
        data->string[data->size - 1] = 0;
76 
        data->len = data->size;
77 
        return count;
78 
    }
79 
 
80 
    if (i <= count) {
3397 rimsky 81 
        /*
82 
         * We have not enought space for whole string with the trailing
83 
         * zero => print only a part of string.
84 
         */
85 
        memcpy((void *)(data->string + data->len), (void *)str, i - 1);
86 
        data->string[data->size - 1] = 0;
87 
        data->len = data->size;
88 
        return count;
1617 cejka 89 
    }
90 
 
91 
    /* Buffer is big enought to print whole string */
92 
    memcpy((void *)(data->string + data->len), (void *)str, count);
93 
    data->len += count;
3397 rimsky 94 
    /*
95 
     * Put trailing zero at end, but not count it into data->len so it could
96 
     * be rewritten next time.
97 
     */
1617 cejka 98 
    data->string[data->len] = 0;
99 
 
1234 cejka 100 
    return count;  
101 
}
102 
 
1623 cejka 103 
/** Print formatted to the given buffer with limited size.
3397 rimsky 104 
 * @param str       Buffer.
105 
 * @param size      Bffer size.
106 
 * @param fmt       Format string.
1623 cejka 107 
 * \see For more details about format string see printf_core.
108 
 */
1234 cejka 109 
int vsnprintf(char *str, size_t size, const char *fmt, va_list ap)
110 
{
111 
    struct vsnprintf_data data = {size, 0, str};
3397 rimsky 112 
    struct printf_spec ps = {
113 
        (int(*)(void *, size_t, void *)) vsnprintf_write,
114 
        &data
115 
    };
1234 cejka 116 
 
3397 rimsky 117 
    /*
118 
     * Print 0 at end of string - fix the case that nothing will be printed.
119 
     */
1234 cejka 120 
    if (size > 0)
121 
        str[0] = 0;
122 
 
123 
    /* vsnprintf_write ensures that str will be terminated by zero. */
124 
    return printf_core(fmt, &ps, ap);
125 
}
126 
 
1866 jermar 127 
/** @}
1653 cejka 128 
 */