source: mainline/uspace/lib/libc/generic/io/vsnprintf.c@ 2e4bd1f

lfn serial ticket/834-toolchain-update topic/msim-upgrade topic/simplify-dev-export
Last change on this file since 2e4bd1f was 2e4bd1f, checked in by Jakub Jermar <jakub@…>, 17 years ago

Cstyle and formatting changes.

  • Property mode set to 100644
File size: 3.9 KB
Line 
1/*
2 * Copyright (c) 2006 Josef 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
29/** @addtogroup libc
30 * @{
31 */
32/** @file
33 */
34
35#include <stdarg.h>
36#include <stdio.h>
37#include <string.h>
38#include <io/printf_core.h>
39
40struct vsnprintf_data {
41 size_t size; /* total space for string */
42 size_t len; /* count of currently used characters */
43 char *string; /* destination string */
44};
45
46/** Write string to given buffer.
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!)
59 */
60static int
61vsnprintf_write(const char *str, size_t count, struct vsnprintf_data *data)
62{
63 size_t i;
64 i = data->size - data->len;
65
66 if (i == 0) {
67 return count;
68 }
69
70 if (i == 1) {
71 /*
72 * We have only one free byte left in buffer => write there
73 * trailing zero.
74 */
75 data->string[data->size - 1] = 0;
76 data->len = data->size;
77 return count;
78 }
79
80 if (i <= count) {
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;
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;
94 /*
95 * Put trailing zero at end, but not count it into data->len so it could
96 * be rewritten next time.
97 */
98 data->string[data->len] = 0;
99
100 return count;
101}
102
103/** Print formatted to the given buffer with limited size.
104 * @param str Buffer.
105 * @param size Bffer size.
106 * @param fmt Format string.
107 * \see For more details about format string see printf_core.
108 */
109int vsnprintf(char *str, size_t size, const char *fmt, va_list ap)
110{
111 struct vsnprintf_data data = {size, 0, str};
112 struct printf_spec ps = {
113 (int(*)(void *, size_t, void *)) vsnprintf_write,
114 &data
115 };
116
117 /*
118 * Print 0 at end of string - fix the case that nothing will be printed.
119 */
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
127/** @}
128 */
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