WebSVN – HelenOS-historic – Diff – /uspace/trunk/libc/generic/io/vsnprintf.c


/*
 * Copyright (C) 2006 Josef Cejka
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * - Redistributions of source code must retain the above copyright
 *   notice, this list of conditions and the following disclaimer.
 * - Redistributions in binary form must reproduce the above copyright
 *   notice, this list of conditions and the following disclaimer in the
 *   documentation and/or other materials provided with the distribution.
 * - The name of the author may not be used to endorse or promote products
 *   derived from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
 * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
 * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
 * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF
 * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 */
 
#include <stdarg.h>
#include <stdio.h>
#include <string.h>
#include <io/printf_core.h>
 
 
struct vsnprintf_data {
    size_t size; /* total space for string */
    size_t len; /* count of currently used characters */
    char *string; /* destination string */
};
 
int vsnprintf_write(const char *str, size_t count, struct vsnprintf_data *data);
 
/** Write string to given buffer.
 * Write at most data->size characters including trailing zero. According to C99 has snprintf to return number
 * of characters that would have been written if enough space had been available. Hence the return value is not
 * number of really printed characters but size of input string. Number of really used characters
 * is stored in data->len.
 * @param str source string to print
 * @param count size of source string
 * @param data structure with destination string, counter of used space and total string size.
 * @return number of characters to print (not characters really printed!)
 */
int vsnprintf_write(const char *str, size_t count, struct vsnprintf_data *data)
{
    size_t i;
    i = data->size - data->len;
 
    if (i == 0) {
        return count;
    }
   
    if (i == 1) {
        /* We have only one free byte left in buffer => write there trailing zero */
        data->string[data->size - 1] = 0;
        data->len = data->size;
        return count;
    }
   
    if (i <= count) {
        /* We have not enought space for whole string with the trailing zero => print only a part of string */
            memcpy((void *)(data->string + data->len), (void *)str, i - 1);
            data->string[data->size - 1] = 0;
            data->len = data->size;
            return count;
    }
   
    /* Buffer is big enought to print whole string */
    memcpy((void *)(data->string + data->len), (void *)str, count);
    data->len += count;
    /* Put trailing zero at end, but not count it into data->len so it could be rewritten next time */
    data->string[data->len] = 0;
 
    return count;  
}
 
/** Print formatted to the given buffer with limited size.
 * @param str   buffer
 * @param size  buffer size
 * @param fmt   format string
 * \see For more details about format string see printf_core.
 */
int vsnprintf(char *str, size_t size, const char *fmt, va_list ap)
{
    struct vsnprintf_data data = {size, 0, str};
    struct printf_spec ps = {(int(*)(void *, size_t, void *))vsnprintf_write, &data};
 
    /* Print 0 at end of string - fix the case that nothing will be printed */
    if (size > 0)
        str[0] = 0;
   
    /* vsnprintf_write ensures that str will be terminated by zero. */
    return printf_core(fmt, &ps, ap);
}
 
 
 

Subversion Repositories HelenOS-historic

(root)/uspace/trunk/libc/generic/io/vsnprintf.c @ 1653 – Rev 1617 → 1623

Rev 1617		Rev 1623
1	/*	1	/*
2	* Copyright (C) 2006 Josef Cejka	2	* Copyright (C) 2006 Josef Cejka
3	* All rights reserved.	3	* All rights reserved.
4	*	4	*
5	* Redistribution and use in source and binary forms, with or without	5	* Redistribution and use in source and binary forms, with or without
6	* modification, are permitted provided that the following conditions	6	* modification, are permitted provided that the following conditions
7	* are met:	7	* are met:
8	*	8	*
9	* - Redistributions of source code must retain the above copyright	9	* - Redistributions of source code must retain the above copyright
10	* notice, this list of conditions and the following disclaimer.	10	* notice, this list of conditions and the following disclaimer.
11	* - Redistributions in binary form must reproduce the above copyright	11	* - Redistributions in binary form must reproduce the above copyright
12	* notice, this list of conditions and the following disclaimer in the	12	* notice, this list of conditions and the following disclaimer in the
13	* documentation and/or other materials provided with the distribution.	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	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.	15	* derived from this software without specific prior written permission.
16	*	16	*
17	* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR	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	18	* IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
19	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.	19	* OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
20	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,	20	* IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT,
21	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT	21	* INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT
22	* NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,	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	23	* DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
24	* THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT	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	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.	26	* THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
27	*/	27	*/
28		28
29	#include <stdarg.h>	29	#include <stdarg.h>
30	#include <stdio.h>	30	#include <stdio.h>
31	#include <string.h>	31	#include <string.h>
32	#include <io/printf_core.h>	32	#include <io/printf_core.h>
33		33
34		34
35	struct vsnprintf_data {	35	struct vsnprintf_data {
36	size_t size; /* total space for string */	36	size_t size; /* total space for string */
37	size_t len; /* count of currently used characters */	37	size_t len; /* count of currently used characters */
38	char string; / destination string */	38	char string; / destination string */
39	};	39	};
40		40
41	int vsnprintf_write(const char str, size_t count, struct vsnprintf_data data);	41	int vsnprintf_write(const char str, size_t count, struct vsnprintf_data data);
42		42
43	/** Write string to given buffer.	43	/** Write string to given buffer.
44	* Write at most data->size characters including trailing zero. According to C99 has snprintf to return number	44	* Write at most data->size characters including trailing zero. According to C99 has snprintf to return number
45	* of characters that would have been written if enough space had been available. Hence the return value is not	45	* of characters that would have been written if enough space had been available. Hence the return value is not
46	* number of really printed characters but size of input string. Number of really used characters	46	* number of really printed characters but size of input string. Number of really used characters
47	* is stored in data->len.	47	* is stored in data->len.
48	* @param str source string to print	48	* @param str source string to print
49	* @param count size of source string	49	* @param count size of source string
50	* @param data structure with destination string, counter of used space and total string size.	50	* @param data structure with destination string, counter of used space and total string size.
51	* @return number of characters to print (not characters really printed!)	51	* @return number of characters to print (not characters really printed!)
52	*/	52	*/
53	int vsnprintf_write(const char str, size_t count, struct vsnprintf_data data)	53	int vsnprintf_write(const char str, size_t count, struct vsnprintf_data data)
54	{	54	{
55	size_t i;	55	size_t i;
56	i = data->size - data->len;	56	i = data->size - data->len;
57		57
58	if (i == 0) {	58	if (i == 0) {
59	return count;	59	return count;
60	}	60	}
61		61
62	if (i == 1) {	62	if (i == 1) {
63	/* We have only one free byte left in buffer => write there trailing zero */	63	/* We have only one free byte left in buffer => write there trailing zero */
64	data->string[data->size - 1] = 0;	64	data->string[data->size - 1] = 0;
65	data->len = data->size;	65	data->len = data->size;
66	return count;	66	return count;
67	}	67	}
68		68
69	if (i <= count) {	69	if (i <= count) {
70	/* We have not enought space for whole string with the trailing zero => print only a part of string */	70	/* We have not enought space for whole string with the trailing zero => print only a part of string */
71	memcpy((void )(data->string + data->len), (void )str, i - 1);	71	memcpy((void )(data->string + data->len), (void )str, i - 1);
72	data->string[data->size - 1] = 0;	72	data->string[data->size - 1] = 0;
73	data->len = data->size;	73	data->len = data->size;
74	return count;	74	return count;
75	}	75	}
76		76
77	/* Buffer is big enought to print whole string */	77	/* Buffer is big enought to print whole string */
78	memcpy((void )(data->string + data->len), (void )str, count);	78	memcpy((void )(data->string + data->len), (void )str, count);
79	data->len += count;	79	data->len += count;
80	/* Put trailing zero at end, but not count it into data->len so it could be rewritten next time */	80	/* Put trailing zero at end, but not count it into data->len so it could be rewritten next time */
81	data->string[data->len] = 0;	81	data->string[data->len] = 0;
82		82
83	return count;	83	return count;
84	}	84	}
85		85
-		86	/** Print formatted to the given buffer with limited size.
-		87	* @param str buffer
-		88	* @param size buffer size
-		89	* @param fmt format string
-		90	* \see For more details about format string see printf_core.
-		91	*/
86	int vsnprintf(char str, size_t size, const char fmt, va_list ap)	92	int vsnprintf(char str, size_t size, const char fmt, va_list ap)
87	{	93	{
88	struct vsnprintf_data data = {size, 0, str};	94	struct vsnprintf_data data = {size, 0, str};
89	struct printf_spec ps = {(int()(void , size_t, void *))vsnprintf_write, &data};	95	struct printf_spec ps = {(int()(void , size_t, void *))vsnprintf_write, &data};
90		96
91	/* Print 0 at end of string - fix the case that nothing will be printed */	97	/* Print 0 at end of string - fix the case that nothing will be printed */
92	if (size > 0)	98	if (size > 0)
93	str[0] = 0;	99	str[0] = 0;
94		100
95	/* vsnprintf_write ensures that str will be terminated by zero. */	101	/* vsnprintf_write ensures that str will be terminated by zero. */
96	return printf_core(fmt, &ps, ap);	102	return printf_core(fmt, &ps, ap);
97	}	103	}
98		104
99		105
100		106