diff options
Diffstat (limited to 'linux/kernel/vsprintf.c')
| -rw-r--r-- | linux/kernel/vsprintf.c | 227 |
1 files changed, 227 insertions, 0 deletions
diff --git a/linux/kernel/vsprintf.c b/linux/kernel/vsprintf.c new file mode 100644 index 0000000..69c0578 --- /dev/null +++ b/linux/kernel/vsprintf.c @@ -0,0 +1,227 @@ +/* vsprintf.c -- Lars Wirzenius & Linus Torvalds. */ +/* + * Wirzenius wrote this portably, Torvalds fucked it up :-) + */ + +#include <stdarg.h> +#include <string.h> + +/* we use this so that we can do without the ctype library */ +#define is_digit(c) ((c) >= '0' && (c) <= '9') + +static int skip_atoi(const char **s) +{ + int i=0; + + while (is_digit(**s)) + i = i*10 + *((*s)++) - '0'; + return i; +} + +#define ZEROPAD 1 /* pad with zero */ +#define SIGN 2 /* unsigned/signed long */ +#define PLUS 4 /* show plus */ +#define SPACE 8 /* space if plus */ +#define LEFT 16 /* left justified */ +#define SPECIAL 32 /* 0x */ +#define SMALL 64 /* use 'abcdef' instead of 'ABCDEF' */ + +#define do_div(n,base) ({ \ +int __res; \ +__asm__("divl %4":"=a" (n),"=d" (__res):"0" (n),"1" (0),"r" (base)); \ +__res; }) + +static char * number(char * str, int num, int base, int size, int precision + ,int type) +{ + char c,sign,tmp[36]; + const char *digits="0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ"; + int i; + + if (type&SMALL) digits="0123456789abcdefghijklmnopqrstuvwxyz"; + if (type&LEFT) type &= ~ZEROPAD; + if (base<2 || base>36) + return 0; + c = (type & ZEROPAD) ? '0' : ' ' ; + if (type&SIGN && num<0) { + sign='-'; + num = -num; + } else + sign=(type&PLUS) ? '+' : ((type&SPACE) ? ' ' : 0); + if (sign) size--; + if (type&SPECIAL) + if (base==16) size -= 2; + else if (base==8) size--; + i=0; + if (num==0) + tmp[i++]='0'; + else while (num!=0) + tmp[i++]=digits[do_div(num,base)]; + if (i>precision) precision=i; + size -= precision; + if (!(type&(ZEROPAD+LEFT))) + while(size-->0) + *str++ = ' '; + if (sign) + *str++ = sign; + if (type&SPECIAL) + if (base==8) + *str++ = '0'; + else if (base==16) { + *str++ = '0'; + *str++ = digits[33]; + } + if (!(type&LEFT)) + while(size-->0) + *str++ = c; + while(i<precision--) + *str++ = '0'; + while(i-->0) + *str++ = tmp[i]; + while(size-->0) + *str++ = ' '; + return str; +} + +int vsprintf(char *buf, const char *fmt, va_list args) +{ + int len; + int i; + char * str; + char *s; + int *ip; + + int flags; /* flags to number() */ + + int field_width; /* width of output field */ + int precision; /* min. # of digits for integers; max + number of chars for from string */ + int qualifier; /* 'h', 'l', or 'L' for integer fields */ + + for (str=buf ; *fmt ; ++fmt) { + if (*fmt != '%') { + *str++ = *fmt; + continue; + } + + /* process flags */ + flags = 0; + repeat: + ++fmt; /* this also skips first '%' */ + switch (*fmt) { + case '-': flags |= LEFT; goto repeat; + case '+': flags |= PLUS; goto repeat; + case ' ': flags |= SPACE; goto repeat; + case '#': flags |= SPECIAL; goto repeat; + case '0': flags |= ZEROPAD; goto repeat; + } + + /* get field width */ + field_width = -1; + if (is_digit(*fmt)) + field_width = skip_atoi(&fmt); + else if (*fmt == '*') { + /* it's the next argument */ + field_width = va_arg(args, int); + if (field_width < 0) { + field_width = -field_width; + flags |= LEFT; + } + } + + /* get the precision */ + precision = -1; + if (*fmt == '.') { + ++fmt; + if (is_digit(*fmt)) + precision = skip_atoi(&fmt); + else if (*fmt == '*') { + /* it's the next argument */ + precision = va_arg(args, int); + } + if (precision < 0) + precision = 0; + } + + /* get the conversion qualifier */ + qualifier = -1; + if (*fmt == 'h' || *fmt == 'l' || *fmt == 'L') { + qualifier = *fmt; + ++fmt; + } + + switch (*fmt) { + case 'c': + if (!(flags & LEFT)) + while (--field_width > 0) + *str++ = ' '; + *str++ = (unsigned char) va_arg(args, int); + while (--field_width > 0) + *str++ = ' '; + break; + + case 's': + s = va_arg(args, char *); + len = strlen(s); + if (precision < 0) + precision = len; + else if (len > precision) + len = precision; + + if (!(flags & LEFT)) + while (len < field_width--) + *str++ = ' '; + for (i = 0; i < len; ++i) + *str++ = *s++; + while (len < field_width--) + *str++ = ' '; + break; + + case 'o': + str = number(str, va_arg(args, unsigned long), 8, + field_width, precision, flags); + break; + + case 'p': + if (field_width == -1) { + field_width = 8; + flags |= ZEROPAD; + } + str = number(str, + (unsigned long) va_arg(args, void *), 16, + field_width, precision, flags); + break; + + case 'x': + flags |= SMALL; + case 'X': + str = number(str, va_arg(args, unsigned long), 16, + field_width, precision, flags); + break; + + case 'd': + case 'i': + flags |= SIGN; + case 'u': + str = number(str, va_arg(args, unsigned long), 10, + field_width, precision, flags); + break; + + case 'n': + ip = va_arg(args, int *); + *ip = (str - buf); + break; + + default: + if (*fmt != '%') + *str++ = '%'; + if (*fmt) + *str++ = *fmt; + else + --fmt; + break; + } + } + *str = '\0'; + return str-buf; +} |