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1.1 root 1: /* vsprintf.c -- Lars Wirzenius & Linus Torvalds. */
2: /*
3: * Wirzenius wrote this portably, Torvalds fucked it up :-)
4: */
5:
6: #include <stdarg.h>
7: #include <string.h>
8:
9: /* we use this so that we can do without the ctype library */
10: #define is_digit(c) ((c) >= '0' && (c) <= '9')
11:
12: static int skip_atoi(const char **s)
13: {
14: int i=0;
15:
16: while (is_digit(**s))
17: i = i*10 + *((*s)++) - '0';
18: return i;
19: }
20:
21: #define ZEROPAD 1 /* pad with zero */
22: #define SIGN 2 /* unsigned/signed long */
23: #define PLUS 4 /* show plus */
24: #define SPACE 8 /* space if plus */
25: #define LEFT 16 /* left justified */
26: #define SPECIAL 32 /* 0x */
27: #define SMALL 64 /* use 'abcdef' instead of 'ABCDEF' */
28:
29: #define do_div(n,base) ({ \
30: int __res; \
31: __asm__("divl %4":"=a" (n),"=d" (__res):"0" (n),"1" (0),"r" (base)); \
32: __res; })
33:
34: static char * number(char * str, int num, int base, int size, int precision
35: ,int type)
36: {
37: char c,sign,tmp[36];
38: const char *digits="0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
39: int i;
40:
41: if (type&SMALL) digits="0123456789abcdefghijklmnopqrstuvwxyz";
42: if (type&LEFT) type &= ~ZEROPAD;
43: if (base<2 || base>36)
44: return 0;
45: c = (type & ZEROPAD) ? '0' : ' ' ;
46: if (type&SIGN && num<0) {
47: sign='-';
48: num = -num;
49: } else
50: sign=(type&PLUS) ? '+' : ((type&SPACE) ? ' ' : 0);
51: if (sign) size--;
52: if (type&SPECIAL)
53: if (base==16) size -= 2;
54: else if (base==8) size--;
55: i=0;
56: if (num==0)
57: tmp[i++]='0';
58: else while (num!=0)
59: tmp[i++]=digits[do_div(num,base)];
60: if (i>precision) precision=i;
61: size -= precision;
62: if (!(type&(ZEROPAD+LEFT)))
63: while(size-->0)
64: *str++ = ' ';
65: if (sign)
66: *str++ = sign;
67: if (type&SPECIAL)
68: if (base==8)
69: *str++ = '0';
70: else if (base==16) {
71: *str++ = '0';
72: *str++ = digits[33];
73: }
74: if (!(type&LEFT))
75: while(size-->0)
76: *str++ = c;
77: while(i<precision--)
78: *str++ = '0';
79: while(i-->0)
80: *str++ = tmp[i];
81: while(size-->0)
82: *str++ = ' ';
83: return str;
84: }
85:
86: int vsprintf(char *buf, const char *fmt, va_list args)
87: {
88: int len;
89: int i;
90: char * str;
91: char *s;
92: int *ip;
93:
94: int flags; /* flags to number() */
95:
96: int field_width; /* width of output field */
97: int precision; /* min. # of digits for integers; max
98: number of chars for from string */
99: int qualifier; /* 'h', 'l', or 'L' for integer fields */
100:
101: for (str=buf ; *fmt ; ++fmt) {
102: if (*fmt != '%') {
103: *str++ = *fmt;
104: continue;
105: }
106:
107: /* process flags */
108: flags = 0;
109: repeat:
110: ++fmt; /* this also skips first '%' */
111: switch (*fmt) {
112: case '-': flags |= LEFT; goto repeat;
113: case '+': flags |= PLUS; goto repeat;
114: case ' ': flags |= SPACE; goto repeat;
115: case '#': flags |= SPECIAL; goto repeat;
116: case '0': flags |= ZEROPAD; goto repeat;
117: }
118:
119: /* get field width */
120: field_width = -1;
121: if (is_digit(*fmt))
122: field_width = skip_atoi(&fmt);
123: else if (*fmt == '*') {
124: /* it's the next argument */
125: field_width = va_arg(args, int);
126: if (field_width < 0) {
127: field_width = -field_width;
128: flags |= LEFT;
129: }
130: }
131:
132: /* get the precision */
133: precision = -1;
134: if (*fmt == '.') {
135: ++fmt;
136: if (is_digit(*fmt))
137: precision = skip_atoi(&fmt);
138: else if (*fmt == '*') {
139: /* it's the next argument */
140: precision = va_arg(args, int);
141: }
142: if (precision < 0)
143: precision = 0;
144: }
145:
146: /* get the conversion qualifier */
147: qualifier = -1;
148: if (*fmt == 'h' || *fmt == 'l' || *fmt == 'L') {
149: qualifier = *fmt;
150: ++fmt;
151: }
152:
153: switch (*fmt) {
154: case 'c':
155: if (!(flags & LEFT))
156: while (--field_width > 0)
157: *str++ = ' ';
158: *str++ = (unsigned char) va_arg(args, int);
159: while (--field_width > 0)
160: *str++ = ' ';
161: break;
162:
163: case 's':
164: s = va_arg(args, char *);
165: len = strlen(s);
166: if (precision < 0)
167: precision = len;
168: else if (len > precision)
169: len = precision;
170:
171: if (!(flags & LEFT))
172: while (len < field_width--)
173: *str++ = ' ';
174: for (i = 0; i < len; ++i)
175: *str++ = *s++;
176: while (len < field_width--)
177: *str++ = ' ';
178: break;
179:
180: case 'o':
181: str = number(str, va_arg(args, unsigned long), 8,
182: field_width, precision, flags);
183: break;
184:
185: case 'p':
186: if (field_width == -1) {
187: field_width = 8;
188: flags |= ZEROPAD;
189: }
190: str = number(str,
191: (unsigned long) va_arg(args, void *), 16,
192: field_width, precision, flags);
193: break;
194:
195: case 'x':
196: flags |= SMALL;
197: case 'X':
198: str = number(str, va_arg(args, unsigned long), 16,
199: field_width, precision, flags);
200: break;
201:
202: case 'd':
203: case 'i':
204: flags |= SIGN;
205: case 'u':
206: str = number(str, va_arg(args, unsigned long), 10,
207: field_width, precision, flags);
208: break;
209:
210: case 'n':
211: ip = va_arg(args, int *);
212: *ip = (str - buf);
213: break;
214:
215: default:
216: if (*fmt != '%')
217: *str++ = '%';
218: if (*fmt)
219: *str++ = *fmt;
220: else
221: --fmt;
222: break;
223: }
224: }
225: *str = '\0';
226: return str-buf;
227: }
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