Logo Search packages:      
Sourcecode: ld.so version File versions

vsprintf.c

/*
 *  vsprintf.c
 *
 *  Copyright (C) 1991-1996  Linus Torvalds
 */

/* 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 LARGE     64          /* use 'ABCDEF' instead of 'abcdef' */

#define do_div(n,base) ({ \
int __res; \
__res = ((unsigned long) n) % (unsigned) base; \
n = ((unsigned long) n) / (unsigned) base; \
__res; })

#define ADD_CHAR(s,n,c) ( ((n) > 1) ? *(s)++ = (c), (n)-- : (c) )

static char * number(char * str, int * bufsize, long num, int base, int size, int precision
      ,int type)
{
      char c,sign,tmp[66];
      const char *digits="0123456789abcdefghijklmnopqrstuvwxyz";
      int i;

      if (type & LARGE)
            digits = "0123456789ABCDEFGHIJKLMNOPQRSTUVWXYZ";
      if (type & LEFT)
            type &= ~ZEROPAD;
      if (base < 2 || base > 36)
            return 0;
      c = (type & ZEROPAD) ? '0' : ' ';
      sign = 0;
      if (type & SIGN) {
            if (num < 0) {
                  sign = '-';
                  num = -num;
                  size--;
            } else if (type & PLUS) {
                  sign = '+';
                  size--;
            } else if (type & SPACE) {
                  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)
                  ADD_CHAR(str, *bufsize, ' ');
      if (sign)
            ADD_CHAR(str, *bufsize, sign);
      if (type & SPECIAL)
            if (base==8)
                  ADD_CHAR(str, *bufsize, '0');
            else if (base==16) {
                  ADD_CHAR(str, *bufsize, '0');
                  ADD_CHAR(str, *bufsize, digits[33]);
            }
      if (!(type & LEFT))
            while (size-- > 0)
                  ADD_CHAR(str, *bufsize, c);
      while (i < precision--)
            ADD_CHAR(str, *bufsize, '0');
      while (i-- > 0)
            ADD_CHAR(str, *bufsize, tmp[i]);
      while (size-- > 0)
            ADD_CHAR(str, *bufsize, ' ');
      return str;
}

int vsnprintf(char *buf, int bufsize, const char *fmt, va_list args)
{
      int len;
      unsigned long num;
      int i, base;
      char * str;
      const char *s;

      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 != '%') {
                  ADD_CHAR(str, bufsize, *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 == '*') {
                  ++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 == '*') {
                        ++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;
            }

            /* default base */
            base = 10;

            switch (*fmt) {
            case 'c':
                  if (!(flags & LEFT))
                        while (--field_width > 0)
                              ADD_CHAR(str, bufsize, ' ');
                  ADD_CHAR(str, bufsize, (unsigned char) va_arg(args, int));
                  while (--field_width > 0)
                        ADD_CHAR(str, bufsize, ' ');
                  continue;

            case 's':
                  s = va_arg(args, char *);
                  if (!s)
                        s = "<NULL>";

                  len = strlen(s);

                  if (!(flags & LEFT))
                        while (len < field_width--)
                              ADD_CHAR(str, bufsize, ' ');
                  for (i = 0; i < len; ++i)
                        ADD_CHAR(str, bufsize, *s++);
                  while (len < field_width--)
                        ADD_CHAR(str, bufsize, ' ');
                  continue;

            case 'p':
                  if (field_width == -1) {
                        field_width = 2*sizeof(void *);
                        flags |= ZEROPAD;
                  }
                  str = number(str, &bufsize,
                        (unsigned long) va_arg(args, void *), 16,
                        field_width, precision, flags);
                  continue;


            case 'n':
                  if (qualifier == 'l') {
                        long * ip = va_arg(args, long *);
                        *ip = (str - buf);
                  } else {
                        int * ip = va_arg(args, int *);
                        *ip = (str - buf);
                  }
                  continue;

            /* integer number formats - set up the flags and "break" */
            case 'o':
                  base = 8;
                  break;

            case 'X':
                  flags |= LARGE;
            case 'x':
                  base = 16;
                  break;

            case 'd':
            case 'i':
                  flags |= SIGN;
            case 'u':
                  break;

            default:
                  if (*fmt != '%')
                        ADD_CHAR(str, bufsize, '%');
                  if (*fmt)
                        ADD_CHAR(str, bufsize, *fmt);
                  else
                        --fmt;
                  continue;
            }
            if (qualifier == 'l')
                  num = va_arg(args, unsigned long);
            else if (qualifier == 'h')
                  if (flags & SIGN)
                        num = va_arg(args, short);
                  else
                        num = va_arg(args, unsigned short);
            else if (flags & SIGN)
                  num = va_arg(args, int);
            else
                  num = va_arg(args, unsigned int);
            str = number(str, &bufsize, num, base, field_width, precision, flags);
      }
      *str = '\0';
      return str-buf;
}

int snprintf(char * buf, int bufsize, const char *fmt, ...)
{
      va_list args;
      int i;

      va_start(args, fmt);
      i=vsnprintf(buf,bufsize,fmt,args);
      va_end(args);
      return i;
}


Generated by  Doxygen 1.6.0   Back to index