LibC/Stdio/vsnprintf_ss.c

/*  $NetBSD: vsnprintf_ss.c,v 1.2.2.1 2007/05/07 19:49:09 pavel Exp $ */

/*-
 * Copyright (c) 1990, 1993
 *  The Regents of the University of California.  All rights reserved.
 *
 * This code is derived from software contributed to Berkeley by
 * Chris Torek.
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in the
 *    documentation and/or other materials provided with the distribution.
 * 3. Neither the name of the University nor the names of its contributors
 *    may be used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND
 * ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE
 * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
 * ARE DISCLAIMED.  IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE
 * FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
 * DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS
 * OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
 * HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY
 * OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
 * SUCH DAMAGE.
 */
#include  <LibConfig.h>
#include <sys/EfiCdefs.h>
#if defined(LIBC_SCCS) && !defined(lint)
#if 0
static char sccsid[] = "@(#)vsnprintf.c 8.1 (Berkeley) 6/4/93";
#else
__RCSID("$NetBSD: vsnprintf_ss.c,v 1.2.2.1 2007/05/07 19:49:09 pavel Exp $");
#endif
#endif /* LIBC_SCCS and not lint */

#include "namespace.h"

#include <sys/types.h>
#include <inttypes.h>
#include <assert.h>
#include <stdio.h>
#include <errno.h>
#include <stdarg.h>
#include <string.h>
#include "reentrant.h"
#include "extern.h"
#include "local.h"

#ifdef __weak_alias
__weak_alias(vsnprintf_ss,_vsnprintf_ss)
#endif

/*
 * vsnprintf_ss: scaled down version of printf(3).
 *
 * this version based on vfprintf() from libc which was derived from
 * software contributed to Berkeley by Chris Torek.
 *
 */

/*
 * macros for converting digits to letters and vice versa
 */
#define to_digit(c) ((c) - '0')
#define is_digit(c) ((unsigned)to_digit(c) <= 9)
#define to_char(n)  (char)((n) + '0')

/*
 * flags used during conversion.
 */
#define ALT   0x001   /* alternate form */
#define HEXPREFIX 0x002   /* add 0x or 0X prefix */
#define LADJUST   0x004   /* left adjustment */
#define LONGDBL   0x008   /* long double; unimplemented */
#define LONGINT   0x010   /* long integer */
#define QUADINT   0x020   /* quad integer */
#define SHORTINT  0x040   /* short integer */
#define MAXINT    0x080   /* intmax_t */
#define PTRINT    0x100   /* intptr_t */
#define SIZEINT   0x200   /* size_t */
#define ZEROPAD   0x400   /* zero (as opposed to blank) pad */
#define FPT   0x800   /* Floating point number */

  /*
   * To extend shorts properly, we need both signed and unsigned
   * argument extraction methods.
   */
#define SARG() \
  ((INT64)(flags&MAXINT ? va_arg(ap, intmax_t) : \
      flags&PTRINT ? va_arg(ap, intptr_t) : \
      flags&SIZEINT ? va_arg(ap, ssize_t) : /* XXX */ \
      flags&QUADINT ? va_arg(ap, quad_t) : \
      flags&LONGINT ? va_arg(ap, long) : \
      flags&SHORTINT ? (short)va_arg(ap, int) : \
      va_arg(ap, int)))

#define UARG() \
  ((UINT64)(flags&MAXINT ? va_arg(ap, uintmax_t) : \
      flags&PTRINT ? va_arg(ap, uintptr_t) : \
      flags&SIZEINT ? va_arg(ap, size_t) : \
      flags&QUADINT ? va_arg(ap, u_quad_t) : \
      flags&LONGINT ? va_arg(ap, unsigned long) : \
      flags&SHORTINT ? (u_short)va_arg(ap, int) : \
      va_arg(ap, u_int)))

#define PUTCHAR(C) do {         \
  if (sbuf < tailp)       \
    *sbuf++ = (C);        \
} while (/*CONSTCOND*/0)

int
vsnprintf_ss(char *sbuf, size_t slen, const char *fmt0, va_list ap)
{
  const char *fmt;  /* format string */
  int ch;     /* character from fmt */
  int n;      /* handy integer (short term usage) */
  char *cp;   /* handy char pointer (short term usage) */
  int flags;    /* flags as above */
  int ret;    /* return value accumulator */
  int width;    /* width from format (%8d), or 0 */
  int prec;   /* precision from format (%.3d), or -1 */
  char sign;    /* sign prefix (' ', '+', '-', or \0) */

  u_quad_t _uquad;  /* integer arguments %[diouxX] */
  enum { OCT, DEC, HEX } base;/* base for [diouxX] conversion */
  int dprec;    /* a copy of prec if [diouxX], 0 otherwise */
  int realsz;   /* field size expanded by dprec */
  int size;   /* size of converted field or string */
  const char *xdigs;  /* digits for [xX] conversion */
  char bf[128];     /* space for %c, %[diouxX] */
  char *tailp;    /* tail pointer for snprintf */

  static const char xdigs_lower[16] = "0123456789abcdef";
  static const char xdigs_upper[16] = "0123456789ABCDEF";


  _DIAGASSERT(n == 0 || sbuf != NULL);
  _DIAGASSERT(fmt != NULL);

  tailp = sbuf + slen;

  cp = NULL;  /* XXX: shutup gcc */
  size = 0; /* XXX: shutup gcc */

  fmt = fmt0;
  ret = 0;

  xdigs = NULL;   /* XXX: shut up gcc warning */

  /*
   * Scan the format for conversions (`%' character).
   */
  for (;;) {
    while (*fmt != '%' && *fmt) {
      ret++;
      PUTCHAR(*fmt++);
    }
    if (*fmt == 0)
      goto done;

    fmt++;    /* skip over '%' */

    flags = 0;
    dprec = 0;
    width = 0;
    prec = -1;
    sign = '\0';

rflag:    ch = *fmt++;
reswitch: switch (ch) {
    case ' ':
      /*
       * ``If the space and + flags both appear, the space
       * flag will be ignored.''
       *  -- ANSI X3J11
       */
      if (!sign)
        sign = ' ';
      goto rflag;
    case '#':
      flags |= ALT;
      goto rflag;
    case '*':
      /*
       * ``A negative field width argument is taken as a
       * - flag followed by a positive field width.''
       *  -- ANSI X3J11
       * They don't exclude field widths read from args.
       */
      if ((width = va_arg(ap, int)) >= 0)
        goto rflag;
      width = -width;
      /* FALLTHROUGH */
    case '-':
      flags |= LADJUST;
      goto rflag;
    case '+':
      sign = '+';
      goto rflag;
    case '.':
      if ((ch = *fmt++) == '*') {
        n = va_arg(ap, int);
        prec = n < 0 ? -1 : n;
        goto rflag;
      }
      n = 0;
      while (is_digit(ch)) {
        n = 10 * n + to_digit(ch);
        ch = *fmt++;
      }
      prec = n < 0 ? -1 : n;
      goto reswitch;
    case '0':
      /*
       * ``Note that 0 is taken as a flag, not as the
       * beginning of a field width.''
       *  -- ANSI X3J11
       */
      flags |= ZEROPAD;
      goto rflag;
    case '1': case '2': case '3': case '4':
    case '5': case '6': case '7': case '8': case '9':
      n = 0;
      do {
        n = 10 * n + to_digit(ch);
        ch = *fmt++;
      } while (is_digit(ch));
      width = n;
      goto reswitch;
    case 'h':
      flags |= SHORTINT;
      goto rflag;
    case 'j':
      flags |= MAXINT;
      goto rflag;
    case 'l':
      if (*fmt == 'l') {
        fmt++;
        flags |= QUADINT;
      } else {
        flags |= LONGINT;
      }
      goto rflag;
    case 'q':
      flags |= QUADINT;
      goto rflag;
    case 't':
      flags |= PTRINT;
      goto rflag;
    case 'z':
      flags |= SIZEINT;
      goto rflag;
    case 'c':
      *(cp = bf) = va_arg(ap, int);
      size = 1;
      sign = '\0';
      break;
    case 'D':
      flags |= LONGINT;
      /*FALLTHROUGH*/
    case 'd':
    case 'i':
      _uquad = SARG();
      if ((quad_t)_uquad < 0) {
        _uquad = -_uquad;
        sign = '-';
      }
      base = DEC;
      goto number;
    case 'n':
      if (flags & MAXINT)
        *va_arg(ap, intmax_t *) = ret;
      else if (flags & PTRINT)
        *va_arg(ap, intptr_t *) = ret;
      else if (flags & SIZEINT)
        *va_arg(ap, ssize_t *) = ret;
      else if (flags & QUADINT)
        *va_arg(ap, quad_t *) = ret;
      else if (flags & LONGINT)
        *va_arg(ap, long *) = (long)ret;
      else if (flags & SHORTINT)
        *va_arg(ap, short *) = (short)ret;
      else
        *va_arg(ap, int *) = ret;
      continue; /* no output */
    case 'O':
      flags |= LONGINT;
      /*FALLTHROUGH*/
    case 'o':
      _uquad = UARG();
      base = OCT;
      goto nosign;
    case 'p':
      /*
       * ``The argument shall be a pointer to void.  The
       * value of the pointer is converted to a sequence
       * of printable characters, in an implementation-
       * defined manner.''
       *  -- ANSI X3J11
       */
      /* NOSTRICT */
      _uquad = (u_long)va_arg(ap, void *);
      base = HEX;
      xdigs = xdigs_lower;
      flags |= HEXPREFIX;
      ch = 'x';
      goto nosign;
    case 's':
      if ((cp = va_arg(ap, char *)) == NULL)
        /*XXXUNCONST*/
        cp = __UNCONST("(null)");
      if (prec >= 0) {
        /*
         * can't use strlen; can only look for the
         * NUL in the first `prec' characters, and
         * strlen() will go further.
         */
        char *p = memchr(cp, 0, (size_t)prec);

        if (p != NULL) {
          size = p - cp;
          if (size > prec)
            size = prec;
        } else
          size = prec;
      } else
        size = strlen(cp);
      sign = '\0';
      break;
    case 'U':
      flags |= LONGINT;
      /*FALLTHROUGH*/
    case 'u':
      _uquad = UARG();
      base = DEC;
      goto nosign;
    case 'X':
      xdigs = xdigs_upper;
      goto hex;
    case 'x':
      xdigs = xdigs_lower;
hex:      _uquad = UARG();
      base = HEX;
      /* leading 0x/X only if non-zero */
      if (flags & ALT && _uquad != 0)
        flags |= HEXPREFIX;

      /* unsigned conversions */
nosign:     sign = '\0';
      /*
       * ``... diouXx conversions ... if a precision is
       * specified, the 0 flag will be ignored.''
       *  -- ANSI X3J11
       */
number:     if ((dprec = prec) >= 0)
        flags &= ~ZEROPAD;

      /*
       * ``The result of converting a zero value with an
       * explicit precision of zero is no characters.''
       *  -- ANSI X3J11
       */
      cp = bf + sizeof(bf);
      if (_uquad != 0 || prec != 0) {
        /*
         * Unsigned mod is hard, and unsigned mod
         * by a constant is easier than that by
         * a variable; hence this switch.
         */
        switch (base) {
        case OCT:
          do {
            *--cp = to_char(_uquad & 7);
            _uquad >>= 3;
          } while (_uquad);
          /* handle octal leading 0 */
          if (flags & ALT && *cp != '0')
            *--cp = '0';
          break;

        case DEC:
          /* many numbers are 1 digit */
          while (_uquad >= 10) {
            *--cp = to_char(_uquad % 10);
            _uquad /= 10;
          }
          *--cp = to_char(_uquad);
          break;

        case HEX:
          do {
            *--cp = xdigs[(size_t)_uquad & 15];
            _uquad >>= 4;
          } while (_uquad);
          break;

        default:
          /*XXXUNCONST*/
          cp = __UNCONST("bug bad base");
          size = strlen(cp);
          goto skipsize;
        }
      }
      size = bf + sizeof(bf) - cp;
    skipsize:
      break;
    default:  /* "%?" prints ?, unless ? is NUL */
      if (ch == '\0')
        goto done;
      /* pretend it was %c with argument ch */
      cp = bf;
      *cp = ch;
      size = 1;
      sign = '\0';
      break;
    }

    /*
     * All reasonable formats wind up here.  At this point, `cp'
     * points to a string which (if not flags&LADJUST) should be
     * padded out to `width' places.  If flags&ZEROPAD, it should
     * first be prefixed by any sign or other prefix; otherwise,
     * it should be blank padded before the prefix is emitted.
     * After any left-hand padding and prefixing, emit zeroes
     * required by a decimal [diouxX] precision, then print the
     * string proper, then emit zeroes required by any leftover
     * floating precision; finally, if LADJUST, pad with blanks.
     *
     * Compute actual size, so we know how much to pad.
     * size excludes decimal prec; realsz includes it.
     */
    realsz = dprec > size ? dprec : size;
    if (sign)
      realsz++;
    else if (flags & HEXPREFIX)
      realsz+= 2;

    /* adjust ret */
    ret += width > realsz ? width : realsz;

    /* right-adjusting blank padding */
    if ((flags & (LADJUST|ZEROPAD)) == 0) {
      n = width - realsz;
      while (n-- > 0)
        PUTCHAR(' ');
    }

    /* prefix */
    if (sign) {
      PUTCHAR(sign);
    } else if (flags & HEXPREFIX) {
      PUTCHAR('0');
      PUTCHAR(ch);
    }

    /* right-adjusting zero padding */
    if ((flags & (LADJUST|ZEROPAD)) == ZEROPAD) {
      n = width - realsz;
      while (n-- > 0)
        PUTCHAR('0');
    }

    /* leading zeroes from decimal precision */
    n = dprec - size;
    while (n-- > 0)
      PUTCHAR('0');

    /* the string or number proper */
    while (size--)
      PUTCHAR(*cp++);
    /* left-adjusting padding (always blank) */
    if (flags & LADJUST) {
      n = width - realsz;
      while (n-- > 0)
        PUTCHAR(' ');
    }
  }

done:
  if (sbuf == tailp)
    sbuf[-1] = '\0';
  else
    *sbuf = '\0';
  return (ret);
  /* NOTREACHED */
}