Annotation of prex/sys/lib/vsprintf.c, Revision 1.1.1.1
1.1 nbrk 1: /*-
2: * Copyright (c) 2005, Kohsuke Ohtani
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: * 1. Redistributions of source code must retain the above copyright
9: * notice, this list of conditions and the following disclaimer.
10: * 2. Redistributions in binary form must reproduce the above copyright
11: * notice, this list of conditions and the following disclaimer in the
12: * documentation and/or other materials provided with the distribution.
13: * 3. Neither the name of the author nor the names of any co-contributors
14: * may be used to endorse or promote products derived from this software
15: * without specific prior written permission.
16: *
17: * THIS SOFTWARE IS PROVIDED BY THE AUTHOR AND CONTRIBUTORS ``AS IS'' AND
18: * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
19: * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
20: * ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR OR CONTRIBUTORS BE LIABLE
21: * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
22: * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
23: * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
24: * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
25: * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
26: * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
27: * SUCH DAMAGE.
28: */
29:
30: /*
31: * vsprintf.c - Format and output data to buffer
32: */
33:
34: #include <kernel.h>
35: #include <sys/types.h>
36:
37: #define isdigit(c) ((unsigned)((c) - '0') < 10)
38:
39: static u_long
40: divide(long *n, int base)
41: {
42: u_long res;
43:
44: res = ((u_long)*n) % base;
45: *n = ((u_long)*n) / base;
46: return res;
47: }
48:
49: static int
50: atoi(const char **s)
51: {
52: int i = 0;
53: while (isdigit((int)**s))
54: i = i * 10 + *((*s)++) - '0';
55: return i;
56: }
57:
58: /*
59: * Print formatted output - scaled down version
60: *
61: * Identifiers:
62: * %d - Decimal signed int
63: * %x - Hex integer
64: * %u - Unsigned integer
65: * %c - Character
66: * %s - String
67: *
68: * Flags:
69: * 0 - Zero pad
70: */
71: int
72: vsprintf(char *buf, const char *fmt, va_list args)
73: {
74: char *p, *str;
75: const char *digits = "0123456789abcdef";
76: char pad, tmp[16];
77: int width, base, sign, i;
78: long num;
79:
80: for (p = buf; *fmt; fmt++) {
81: if (*fmt != '%') {
82: *p++ = *fmt;
83: continue;
84: }
85: /* get flags */
86: ++fmt;
87: pad = ' ';
88: if (*fmt == '0') {
89: pad = '0';
90: fmt++;
91: }
92: /* get width */
93: width = -1;
94: if (isdigit(*fmt)) {
95: width = atoi(&fmt);
96: }
97: base = 10;
98: sign = 0;
99: switch (*fmt) {
100: case 'c':
101: *p++ = (char)va_arg(args, int);
102: continue;
103: case 's':
104: str = va_arg(args, char *);
105: if (str == NULL)
106: str = "<NULL>";
107: for (; *str && width != 0; str++, width--) {
108: *p++ = *str;
109: }
110: while (width-- > 0)
111: *p++ = pad;
112: continue;
113: case 'X':
114: case 'x':
115: base = 16;
116: break;
117: case 'd':
118: sign = 1;
119: break;
120: case 'u':
121: break;
122: default:
123: continue;
124: }
125: num = va_arg(args, long);
126: if (sign && num < 0) {
127: num = -num;
128: *p++ = '-';
129: width--;
130: }
131: i = 0;
132: if (num == 0)
133: tmp[i++] = '0';
134: else
135: while (num != 0)
136: tmp[i++] = digits[divide(&num, base)];
137: width -= i;
138: while (width-- > 0)
139: *p++ = pad;
140: while (i-- > 0)
141: *p++ = tmp[i];
142: }
143: *p = '\0';
144: return 0;
145: }
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