/** @file
  valist worker function for the wide-character fscanf.

  Copyright (c) 2010 - 2014, Intel Corporation. All rights reserved.<BR>
  This program and the accompanying materials are licensed and made available under
  the terms and conditions of the BSD License that accompanies this distribution.
  The full text of the license may be found at
  http://opensource.org/licenses/bsd-license.

  THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS,
  WITHOUT WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.

 * 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. All advertising materials mentioning features or use of this software
 *    must display the following acknowledgement:
 *  This product includes software developed by the University of
 *  California, Berkeley and its contributors.
 * 4. 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.

  FreeBSD: src/lib/libc/stdio/vfwscanf.c,v 1.12 2004/05/02 20:13:29 obrien Exp
  NetBSD: vfwscanf.c,v 1.2 2005/06/12 05:48:41 lukem Exp
 */
#include  <LibConfig.h>
#include  <sys/EfiCdefs.h>

#include  "namespace.h"
#include  <ctype.h>
#include  <inttypes.h>
#include  <stdio.h>
#include  <stdlib.h>
#include  <stddef.h>
#include  <stdarg.h>
#include  <string.h>
#include  <limits.h>
#include  <wchar.h>
#include  <wctype.h>

#include  "reentrant.h"
#include  "local.h"

#ifndef NO_FLOATING_POINT
#include  <locale.h>
#endif

#if defined(_MSC_VER)           /* Handle Microsoft VC++ compiler specifics. */
  #pragma warning ( disable : 4244 )  // Allow wint_t to wchar_t conversions
  #pragma warning ( disable : 4305 )  // Allow truncation from UINT64 to void*
  #pragma warning ( disable : 4701 )  // Disable false warning for local variable p near line 375
#endif


#define BUF   513 /* Maximum length of numeric string. */

/*
 * Flags used during conversion.
 */
#define LONG        0x01    /* l: long or double */
#define LONGDBL     0x02    /* L: long double */
#define SHORT       0x04    /* h: short */
#define SUPPRESS    0x08    /* *: suppress assignment */
#define POINTER     0x10    /* p: void * (as hex) */
#define NOSKIP      0x20    /* [ or c: do not skip blanks */
#define LONGLONG    0x400   /* ll: quad_t (+ deprecated q: quad) */
#define INTMAXT     0x800   /* j: intmax_t */
#define PTRDIFFT    0x1000  /* t: ptrdiff_t */
#define SIZET       0x2000  /* z: size_t */
#define SHORTSHORT  0x4000  /* hh: char */
#define UNSIGNED    0x8000  /* %[oupxX] conversions */

/*
 * The following are used in integral conversions only:
 * SIGNOK, NDIGITS, PFXOK, and NZDIGITS
 */
#define SIGNOK    0x40    /* +/- is (still) legal */
#define NDIGITS   0x80    /* no digits detected */
#define PFXOK     0x100   /* 0x prefix is (still) legal */
#define NZDIGITS  0x200   /* no zero digits detected */
#define HAVESIGN  0x10000 /* sign detected */

/*
 * Conversion types.
 */
#define CT_CHAR   0 /* %c conversion */
#define CT_CCL    1 /* %[...] conversion */
#define CT_STRING 2 /* %s conversion */
#define CT_INT    3 /* %[dioupxX] conversion */
#define CT_FLOAT  4 /* %[efgEFG] conversion */

static int parsefloat(FILE *, wchar_t *, wchar_t *);

#define INCCL(_c) \
  (cclcompl ? (wmemchr(ccls, (_c), (size_t)(ccle - ccls)) == NULL) : \
  (wmemchr(ccls, (_c), (size_t)(ccle - ccls)) != NULL))

/*
 * MT-safe version.
 */
int
vfwscanf(FILE * __restrict fp, const wchar_t * __restrict fmt, va_list ap)
{
  int ret;

  FLOCKFILE(fp);
  _SET_ORIENTATION(fp, 1);
  ret = __vfwscanf_unlocked(fp, fmt, ap);
  FUNLOCKFILE(fp);
  return (ret);
}

/*
 * Non-MT-safe version.
 */
int
__vfwscanf_unlocked(FILE * __restrict fp, const wchar_t * __restrict fmt, va_list ap)
{
  wint_t                  c;                            /* character from format, or conversion */
  size_t                  width;                        /* field width, or 0 */
  wchar_t                *p                   = NULL;   /* points into all kinds of strings */
  int                     n;                            /* handy integer */
  int                     flags;                        /* flags as defined above */
  wchar_t                *p0;                           /* saves original value of p when necessary */
  int                     nassigned;                    /* number of fields assigned */
  int                     nconversions;                 /* number of conversions */
  int                     nread;                        /* number of characters consumed from fp */
  int                     base;                         /* base argument to conversion function */
  wchar_t                 buf[BUF];                     /* buffer for numeric conversions */
  const wchar_t          *ccls;                         /* character class start */
  const wchar_t          *ccle;                         /* character class end */
  int                     cclcompl;                     /* ccl is complemented? */
  wint_t                  wi;                           /* handy wint_t */
  char                   *mbp;                          /* multibyte string pointer for %c %s %[ */
  size_t                  nconv;                        /* number of bytes in mb. conversion */
  char                    mbbuf[MB_LEN_MAX];            /* temporary mb. character buffer */
  mbstate_t               mbs;

  static const mbstate_t  initial             = { 0 };
  /* `basefix' is used to avoid `if' tests in the integer scanner */
  static short            basefix[17] =
    { 10, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 };

  nassigned     = 0;
  nconversions  = 0;
  nread         = 0;
  ccls          = NULL;
  ccle          = NULL;
  base          = 0;
  cclcompl      = 0;
  mbp           = NULL;

  for (;;) {
    c = *fmt++;
    if (c == 0)
      return (nassigned);
    if (iswspace(c)) {
      while ((c = __fgetwc_unlock(fp)) != WEOF &&
          iswspace(c))
        ;
      if (c != WEOF)
        ungetwc(c, fp);
      continue;
    }
    if (c != '%')
      goto literal;
    width = 0;
    flags = 0;
    /*
     * switch on the format.  continue if done;
     * break once format type is derived.
     */
again:    c = *fmt++;
    switch (c) {
    case '%':
literal:
      if ((wi = __fgetwc_unlock(fp)) == WEOF)
        goto input_failure;
      if (wi != c) {
        ungetwc(wi, fp);
        goto match_failure;
      }
      nread++;
      continue;

    case '*':
      flags |= SUPPRESS;
      goto again;
    case 'j':
      flags |= INTMAXT;
      goto again;
    case 'l':
      if (flags & LONG) {
        flags &= ~LONG;
        flags |= LONGLONG;
      } else
        flags |= LONG;
      goto again;
    case 'q':
      flags |= LONGLONG;  /* not quite */
      goto again;
    case 't':
      flags |= PTRDIFFT;
      goto again;
    case 'z':
      flags |= SIZET;
      goto again;
    case 'L':
      flags |= LONGDBL;
      goto again;
    case 'h':
      if (flags & SHORT) {
        flags &= ~SHORT;
        flags |= SHORTSHORT;
      } else
        flags |= SHORT;
      goto again;

    case '0': case '1': case '2': case '3': case '4':
    case '5': case '6': case '7': case '8': case '9':
      width = width * 10 + c - '0';
      goto again;

    /*
     * Conversions.
     */
    case 'd':
      c = CT_INT;
      base = 10;
      break;

    case 'i':
      c = CT_INT;
      base = 0;
      break;

    case 'o':
      c = CT_INT;
      flags |= UNSIGNED;
      base = 8;
      break;

    case 'u':
      c = CT_INT;
      flags |= UNSIGNED;
      base = 10;
      break;

    case 'X':
    case 'x':
      flags |= PFXOK; /* enable 0x prefixing */
      c = CT_INT;
      flags |= UNSIGNED;
      base = 16;
      break;

#ifndef NO_FLOATING_POINT
    //case 'A':
    case 'E': case 'F': case 'G':
    //case 'a':
    case 'e': case 'f': case 'g':
      c = CT_FLOAT;
      break;
#endif

    case 'S':
      flags |= LONG;
      /* FALLTHROUGH */
    case 's':
      c = CT_STRING;
      break;

    case '[':
      ccls = fmt;
      if (*fmt == '^') {
        cclcompl = 1;
        fmt++;
      } else
        cclcompl = 0;
      if (*fmt == ']')
        fmt++;
      while (*fmt != '\0' && *fmt != ']')
        fmt++;
      ccle = fmt;
      fmt++;
      flags |= NOSKIP;
      c = CT_CCL;
      break;

    case 'C':
      flags |= LONG;
      /* FALLTHROUGH */
    case 'c':
      flags |= NOSKIP;
      c = CT_CHAR;
      break;

    case 'p': /* pointer format is like hex */
      flags |= POINTER | PFXOK;
      c = CT_INT;   /* assumes sizeof(uintmax_t) */
      flags |= UNSIGNED;  /*      >= sizeof(uintptr_t) */
      base = 16;
      break;

    case 'n':
      nconversions++;
      if (flags & SUPPRESS) /* ??? */
        continue;
      if (flags & SHORTSHORT)
        *va_arg(ap, char *) = (char)nread;
      else if (flags & SHORT)
        *va_arg(ap, short *) = (short)nread;
      else if (flags & LONG)
        *va_arg(ap, long *) = (long)nread;
      else if (flags & LONGLONG)
        *va_arg(ap, INT64 *) = (INT64)nread;    // was quad_t
      else if (flags & INTMAXT)
        *va_arg(ap, intmax_t *) = (intmax_t)nread;
      else if (flags & SIZET)
        *va_arg(ap, size_t *) = (size_t)nread;
      else if (flags & PTRDIFFT)
        *va_arg(ap, ptrdiff_t *) = (ptrdiff_t)nread;
      else
        *va_arg(ap, int *) = nread;
      continue;

    default:
      goto match_failure;

    /*
     * Disgusting backwards compatibility hack. XXX
     */
    case '\0':  /* compat */
      return (EOF);
    }

    /*
     * Consume leading white space, except for formats
     * that suppress this.
     */
    if ((flags & NOSKIP) == 0) {
      while ((wi = __fgetwc_unlock(fp)) != WEOF && iswspace(wi))
        nread++;
      if (wi == WEOF)
        goto input_failure;
      ungetwc(wi, fp);
    }

    /*
     * Do the conversion.
     */
    switch (c) {

    case CT_CHAR:
      /* scan arbitrary characters (sets NOSKIP) */
      if (width == 0)
        width = 1;
      if (flags & LONG) {
        if (!(flags & SUPPRESS))
          p = va_arg(ap, wchar_t *);
        n = 0;
        while (width-- != 0 &&
            (wi = __fgetwc_unlock(fp)) != WEOF) {
          if (!(flags & SUPPRESS))
            *p++ = (wchar_t)wi;
          n++;
        }
        if (n == 0)
          goto input_failure;
        nread += n;
        if (!(flags & SUPPRESS))
          nassigned++;
      } else {
        if (!(flags & SUPPRESS))
          mbp = va_arg(ap, char *);
        n = 0;
        mbs = initial;
        while (width != 0 &&
            (wi = __fgetwc_unlock(fp)) != WEOF) {
          if (width >= MB_CUR_MAX &&
              !(flags & SUPPRESS)) {
            nconv = wcrtomb(mbp, (wchar_t)wi, &mbs);
            if (nconv == (size_t)-1)
              goto input_failure;
          } else {
            nconv = wcrtomb(mbbuf, (wchar_t)wi,
                &mbs);
            if (nconv == (size_t)-1)
              goto input_failure;
            if (nconv > width) {
              ungetwc(wi, fp);
              break;
            }
            if (!(flags & SUPPRESS))
              memcpy(mbp, mbbuf,
                  nconv);
          }
          if (!(flags & SUPPRESS))
            mbp += nconv;
          width -= nconv;
          n++;
        }
        if (n == 0)
          goto input_failure;
        nread += n;
        if (!(flags & SUPPRESS))
          nassigned++;
      }
      nconversions++;
      break;

    case CT_CCL:
      /* scan a (nonempty) character class (sets NOSKIP) */
      if (width == 0)
        width = (size_t)~0; /* `infinity' */
      /* take only those things in the class */
      if ((flags & SUPPRESS) && (flags & LONG)) {
        n = 0;
        while ((wi = __fgetwc_unlock(fp)) != WEOF &&
            width-- != 0 && INCCL(wi))
          n++;
        if (wi != WEOF)
          ungetwc(wi, fp);
        if (n == 0)
          goto match_failure;
      } else if (flags & LONG) {
        p0 = p = va_arg(ap, wchar_t *);
        while ((wi = __fgetwc_unlock(fp)) != WEOF &&
            width-- != 0 && INCCL(wi))
          *p++ = (wchar_t)wi;
        if (wi != WEOF)
          ungetwc(wi, fp);
        n = p - p0;
        if (n == 0)
          goto match_failure;
        *p = 0;
        nassigned++;
      } else {
        if (!(flags & SUPPRESS))
          mbp = va_arg(ap, char *);
        n = 0;
        mbs = initial;
        while ((wi = __fgetwc_unlock(fp)) != WEOF &&
            width != 0 && INCCL(wi)) {
          if (width >= MB_CUR_MAX &&
             !(flags & SUPPRESS)) {
            nconv = wcrtomb(mbp, wi, &mbs);
            if (nconv == (size_t)-1)
              goto input_failure;
          } else {
            nconv = wcrtomb(mbbuf, wi,
                &mbs);
            if (nconv == (size_t)-1)
              goto input_failure;
            if (nconv > width)
              break;
            if (!(flags & SUPPRESS))
              memcpy(mbp, mbbuf,
                  nconv);
          }
          if (!(flags & SUPPRESS))
            mbp += nconv;
          width -= nconv;
          n++;
        }
        if (wi != WEOF)
          ungetwc(wi, fp);
        if (!(flags & SUPPRESS)) {
          *mbp = 0;
          nassigned++;
        }
      }
      nread += n;
      nconversions++;
      break;

    case CT_STRING:
      /* like CCL, but zero-length string OK, & no NOSKIP */
      if (width == 0)
        width = (size_t)~0;
      if ((flags & SUPPRESS) && (flags & LONG)) {
        while ((wi = __fgetwc_unlock(fp)) != WEOF &&
            width-- != 0 &&
            !iswspace(wi))
          nread++;
        if (wi != WEOF)
          ungetwc(wi, fp);
      } else if (flags & LONG) {
        p0 = p = va_arg(ap, wchar_t *);
        while ((wi = __fgetwc_unlock(fp)) != WEOF &&
            width-- != 0 &&
            !iswspace(wi)) {
          *p++ = (wchar_t)wi;
          nread++;
        }
        if (wi != WEOF)
          ungetwc(wi, fp);
        *p = '\0';
        nassigned++;
      } else {
        if (!(flags & SUPPRESS))
          mbp = va_arg(ap, char *);
        mbs = initial;
        while ((wi = __fgetwc_unlock(fp)) != WEOF &&
            width != 0 &&
            !iswspace(wi)) {
          if (width >= MB_CUR_MAX &&
              !(flags & SUPPRESS)) {
            nconv = wcrtomb(mbp, wi, &mbs);
            if (nconv == (size_t)-1)
              goto input_failure;
          } else {
            nconv = wcrtomb(mbbuf, wi,
                &mbs);
            if (nconv == (size_t)-1)
              goto input_failure;
            if (nconv > width)
              break;
            if (!(flags & SUPPRESS))
              memcpy(mbp, mbbuf,
                  nconv);
          }
          if (!(flags & SUPPRESS))
            mbp += nconv;
          width -= nconv;
          nread++;
        }
        if (wi != WEOF)
          ungetwc(wi, fp);
        if (!(flags & SUPPRESS)) {
          *mbp = 0;
          nassigned++;
        }
      }
      nconversions++;
      continue;

    case CT_INT:
      /* scan an integer as if by the conversion function */
      if (width == 0 || width > sizeof(buf) /
          sizeof(*buf) - 1)
        width = sizeof(buf) / sizeof(*buf) - 1;
      flags |= SIGNOK | NDIGITS | NZDIGITS;
      for (p = buf; width; width--) {
        c = __fgetwc_unlock(fp);
        /*
         * Switch on the character; `goto ok'
         * if we accept it as a part of number.
         */
        switch (c) {

        /*
         * The digit 0 is always legal, but is
         * special.  For %i conversions, if no
         * digits (zero or nonzero) have been
         * scanned (only signs), we will have
         * base==0.  In that case, we should set
         * it to 8 and enable 0x prefixing.
         * Also, if we have not scanned zero digits
         * before this, do not turn off prefixing
         * (someone else will turn it off if we
         * have scanned any nonzero digits).
         */
        case '0':
          if (base == 0) {
            base = 8;
            flags |= PFXOK;
          }
          if (flags & NZDIGITS)
              flags &= ~(SIGNOK|NZDIGITS|NDIGITS);
          else
              flags &= ~(SIGNOK|PFXOK|NDIGITS);
          goto ok;

        /* 1 through 7 always legal */
        case '1': case '2': case '3':
        case '4': case '5': case '6': case '7':
          base = basefix[base];
          flags &= ~(SIGNOK | PFXOK | NDIGITS);
          goto ok;

        /* digits 8 and 9 ok iff decimal or hex */
        case '8': case '9':
          base = basefix[base];
          if (base <= 8)
            break;  /* not legal here */
          flags &= ~(SIGNOK | PFXOK | NDIGITS);
          goto ok;

        /* letters ok iff hex */
        case 'A': case 'B': case 'C':
        case 'D': case 'E': case 'F':
        case 'a': case 'b': case 'c':
        case 'd': case 'e': case 'f':
          /* no need to fix base here */
          if (base <= 10)
            break;  /* not legal here */
          flags &= ~(SIGNOK | PFXOK | NDIGITS);
          goto ok;

        /* sign ok only as first character */
        case '+': case '-':
          if (flags & SIGNOK) {
            flags &= ~SIGNOK;
            flags |= HAVESIGN;
            goto ok;
          }
          break;

        /*
         * x ok iff flag still set & 2nd char (or
         * 3rd char if we have a sign).
         */
        case 'x': case 'X':
          if (flags & PFXOK && p ==
              buf + 1 + !!(flags & HAVESIGN)) {
            base = 16;  /* if %i */
            flags &= ~PFXOK;
            goto ok;
          }
          break;
        }

        /*
         * If we got here, c is not a legal character
         * for a number.  Stop accumulating digits.
         */
        if (c != WEOF)
          ungetwc(c, fp);
        break;
    ok:
        /*
         * c is legal: store it and look at the next.
         */
        *p++ = (wchar_t)c;
      }
      /*
       * If we had only a sign, it is no good; push
       * back the sign.  If the number ends in `x',
       * it was [sign] '0' 'x', so push back the x
       * and treat it as [sign] '0'.
       */
      if (flags & NDIGITS) {
        if (p > buf)
          ungetwc(*--p, fp);
        goto match_failure;
      }
      c = p[-1];
      if (c == 'x' || c == 'X') {
        --p;
        ungetwc(c, fp);
      }
      if ((flags & SUPPRESS) == 0) {
        uintmax_t res;

        *p = 0;
        if ((flags & UNSIGNED) == 0)
            res = wcstoimax(buf, NULL, base);
        else
            res = wcstoumax(buf, NULL, base);

        if (flags & POINTER) {
          *va_arg(ap, void **) = (void *)res;
        }
        else if (flags & SHORTSHORT) {
          *va_arg(ap, char *) = (char)res;
        }
        else if (flags & SHORT) {
          *va_arg(ap, short *) = (short)res;
        }
        else if (flags & LONG) {
          *va_arg(ap, long *) = (long)res;
        }
        else if (flags & LONGLONG) {
          *va_arg(ap, INT64 *) = res;   // was quad_t
        }
        else if (flags & INTMAXT) {
          *va_arg(ap, intmax_t *) = res;
        }
        else if (flags & PTRDIFFT) {
          *va_arg(ap, ptrdiff_t *) = (ptrdiff_t)res;
        }
        else if (flags & SIZET) {
          *va_arg(ap, size_t *) = (size_t)res;
        }
        else {
          *va_arg(ap, int *) = (int)res;
        }
        nassigned++;
      }
      nread += p - buf;
      nconversions++;
      break;

#ifndef NO_FLOATING_POINT
    case CT_FLOAT:
      /* scan a floating point number as if by strtod */
      if (width == 0 || width > sizeof(buf) /
          sizeof(*buf) - 1)
        width = sizeof(buf) / sizeof(*buf) - 1;
      if ((width = parsefloat(fp, buf, buf + width)) == 0)
        goto match_failure;
      if ((flags & SUPPRESS) == 0) {
#ifdef REAL_LONG_DOUBLE_SUPPORT
        if (flags & LONGDBL) {
          long double res = wcstold(buf, &p);
          *va_arg(ap, long double *) = res;
        } else
#endif
        if (flags & (LONG | LONGDBL)) {
          double res = wcstod(buf, &p);
          *va_arg(ap, double *) = res;
        }
        else {
          float res = wcstof(buf, &p);
          *va_arg(ap, float *) = res;
        }
#ifdef DEBUG
        if (p - buf != width)
          abort();
#endif
        nassigned++;
      }
      nread += (int)width;
      nconversions++;
      break;
#endif /* !NO_FLOATING_POINT */
    }
  }
input_failure:
  return (nconversions != 0 ? nassigned : EOF);
match_failure:
  return (nassigned);
}

#ifndef NO_FLOATING_POINT
static int
parsefloat(FILE *fp, wchar_t *buf, wchar_t *end)
{
  wchar_t *commit, *p;
  int infnanpos = 0;
  enum {
    S_START, S_GOTSIGN, S_INF, S_NAN, S_MAYBEHEX,
    S_DIGITS, S_FRAC, S_EXP, S_EXPDIGITS
  } state = S_START;
  wchar_t c;
  wchar_t decpt = (wchar_t)(unsigned char)*localeconv()->decimal_point;
  int gotmantdig = 0, ishex = 0;

  /*
   * We set commit = p whenever the string we have read so far
   * constitutes a valid representation of a floating point
   * number by itself.  At some point, the parse will complete
   * or fail, and we will ungetc() back to the last commit point.
   * To ensure that the file offset gets updated properly, it is
   * always necessary to read at least one character that doesn't
   * match; thus, we can't short-circuit "infinity" or "nan(...)".
   */
  commit = buf - 1;
  c = (wchar_t)WEOF;
  for (p = buf; p < end; ) {
    if ((wint_t)(c = __fgetwc_unlock(fp)) == WEOF)
      break;
reswitch:
    switch (state) {
    case S_START:
      state = S_GOTSIGN;
      if (c == '-' || c == '+')
        break;
      else
        goto reswitch;
    case S_GOTSIGN:
      switch (c) {
      case '0':
        state = S_MAYBEHEX;
        commit = p;
        break;
      case 'I':
      case 'i':
        state = S_INF;
        break;
      case 'N':
      case 'n':
        state = S_NAN;
        break;
      default:
        state = S_DIGITS;
        goto reswitch;
      }
      break;
    case S_INF:
      if (infnanpos > 6 ||
          (c != "nfinity"[infnanpos] &&
           c != "NFINITY"[infnanpos]))
        goto parsedone;
      if (infnanpos == 1 || infnanpos == 6)
        commit = p; /* inf or infinity */
      infnanpos++;
      break;
    case S_NAN:
      switch (infnanpos) {
      case -1:  /* XXX kludge to deal with nan(...) */
        goto parsedone;
      case 0:
        if (c != 'A' && c != 'a')
          goto parsedone;
        break;
      case 1:
        if (c != 'N' && c != 'n')
          goto parsedone;
        else
          commit = p;
        break;
      case 2:
        if (c != '(')
          goto parsedone;
        break;
      default:
        if (c == ')') {
          commit = p;
          infnanpos = -2;
        } else if (!iswalnum(c) && c != '_')
          goto parsedone;
        break;
      }
      infnanpos++;
      break;
    case S_MAYBEHEX:
      state = S_DIGITS;
      if (c == 'X' || c == 'x') {
        ishex = 1;
        break;
      } else {  /* we saw a '0', but no 'x' */
        gotmantdig = 1;
        goto reswitch;
      }
    case S_DIGITS:
      if ((ishex && iswxdigit(c)) || iswdigit(c))
        gotmantdig = 1;
      else {
        state = S_FRAC;
        if (c != decpt)
          goto reswitch;
      }
      if (gotmantdig)
        commit = p;
      break;
    case S_FRAC:
      if (((c == 'E' || c == 'e') && !ishex) ||
          ((c == 'P' || c == 'p') && ishex)) {
        if (!gotmantdig)
          goto parsedone;
        else
          state = S_EXP;
      } else if ((ishex && iswxdigit(c)) || iswdigit(c)) {
        commit = p;
        gotmantdig = 1;
      } else
        goto parsedone;
      break;
    case S_EXP:
      state = S_EXPDIGITS;
      if (c == '-' || c == '+')
        break;
      else
        goto reswitch;
    case S_EXPDIGITS:
      if (iswdigit(c))
        commit = p;
      else
        goto parsedone;
      break;
    default:
      abort();
    }
    *p++ = c;
    c = (wchar_t)WEOF;
  }

parsedone:
  if ((wint_t)c != WEOF)
    ungetwc(c, fp);
  while (commit < --p)
    ungetwc(*p, fp);
  *++commit = '\0';
  return (commit - buf);
}
#endif