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printf.c

/* -*- linux-c -*- ------------------------------------------------------- *
 *
 *   Copyright (C) 1991, 1992 Linus Torvalds
 *   Copyright 2007 rPath, Inc. - All Rights Reserved
 *
 *   This file is part of the Linux kernel, and is made available under
 *   the terms of the GNU General Public License version 2.
 *
 * ----------------------------------------------------------------------- */

/*
 * arch/i386/boot/printf.c
 *
 * Oh, it's a waste of space, but oh-so-yummy for debugging.  This
 * version of printf() does not include 64-bit support.  "Live with
 * it."
 *
 */

#include "boot.h"

static int skip_atoi(const char **s)
{
      int i = 0;

      while (isdigit(**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; })

static char *number(char *str, 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)
                  *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;
      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 != '%') {
                  *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 (isdigit(*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 (isdigit(*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)
                              *str++ = ' ';
                  *str++ = (unsigned char)va_arg(args, int);
                  while (--field_width > 0)
                        *str++ = ' ';
                  continue;

            case 's':
                  s = va_arg(args, char *);
                  len = strnlen(s, precision);

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

            case 'p':
                  if (field_width == -1) {
                        field_width = 2 * sizeof(void *);
                        flags |= ZEROPAD;
                  }
                  str = number(str,
                             (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;

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

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

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

int printf(const char *fmt, ...)
{
      char printf_buf[1024];
      va_list args;
      int printed;

      va_start(args, fmt);
      printed = vsprintf(printf_buf, fmt, args);
      va_end(args);

      puts(printf_buf);

      return printed;
}

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