/* VFSCANF.C
 * 
 * Portions Copyright (c) 1990-2004 Nokia Corporation and/or its subsidiary(-ies).
 * All rights reserved.
 */

/* No user fns here. Pesch 15apr92. */

/*
 * Copyright (c) 1990 The Regents of the University of California.
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms are permitted
 * provided that the above copyright notice and this paragraph are
 * duplicated in all such forms and that any documentation,
 * advertising materials, and other materials related to such
 * distribution and use acknowledge that the software was developed
 * by the University of California, Berkeley.  The name of the
 * University may not be used to endorse or promote products derived
 * from this software without specific prior written permission.
 * THIS SOFTWARE IS PROVIDED ``AS IS'' AND WITHOUT ANY EXPRESS OR
 * IMPLIED WARRANTIES, INCLUDING, WITHOUT LIMITATION, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
 */

#include <_ansi.h>
#include <ctype.h>
#include <stdio.h>
#include <stdlib.h>
#include <stdarg.h>
#include "LOCAL.H"

#include "FLOATIO.H"
#define	BUF	(MAXEXP+MAXFRACT+3)	/* 3 = sign + decimal point + NUL */

/*
 * Flags used during conversion.
 */

#define	LONG		0x01	/* l: long or double */
#define	LONGDBL		0x02	/* L: long double; unimplemented */
#define	SHORT		0x04	/* h: short */
#define	SUPPRESS	0x08	/* suppress assignment */
#define	POINTER		0x10	/* weird %p pointer (`fake hex') */
#define	NOSKIP		0x20	/* do not skip blanks */

/*
 * The following are used in numeric conversions only:
 * SIGNOK, NDIGITS, DPTOK, and EXPOK are for floating point;
 * SIGNOK, NDIGITS, PFXOK, and NZDIGITS are for integral.
 */

#define	SIGNOK		0x40	/* +/- is (still) legal */
#define	NDIGITS		0x80	/* no digits detected */

#define	DPTOK		0x100	/* (float) decimal point is still legal */
#define	EXPOK		0x200	/* (float) exponent (e+3, etc) still legal */

#define	PFXOK		0x100	/* 0x prefix is (still) legal */
#define	NZDIGITS	0x200	/* no zero digits detected */

/*
 * Conversion types.
 */

#define	CT_CHAR		0	/* %c conversion */
#define	CT_CCL		1	/* %[...] conversion */
#define	CT_STRING	2	/* %s conversion */
#define	CT_INT		3	/* integer, i.e., strtol or strtoul */
#define	CT_FLOAT	4	/* floating, i.e., strtod */

#define u_char char
#define u_long unsigned long

/*static*/ u_char *__sccl (register char *tab,register u_char *fmt);

/*
 * vfscanf
 */

#define BufferEmpty (fp->_r <= 0 && __srefill(fp))

int
__svfscanf (register FILE *fp,char const *fmt0, va_list ap)
{
  register u_char *fmt = (u_char *) fmt0;
  register int c;		/* character from format, or conversion */
  register size_t width;	/* field width, or 0 */
  register char *p;		/* points into all kinds of strings */
  register int n;		/* handy integer */
  register int flags;		/* flags as defined above */
  register char *p0;		/* saves original value of p when necessary */
  int nassigned;		/* number of fields assigned */
  int nread;			/* number of characters consumed from fp */
  int base = 0;			/* base argument to strtol/strtoul */

  u_long (*ccfn) (const char *_n, char **_end_PTR, int _base) = 0;	/* conversion function (strtol/strtoul) */
  char ccltab[256];		/* character class table for %[...] */
  char buf[BUF];		/* buffer for numeric conversions */

  short *sp;
  int *ip;
  float *flp;
  double *dp;
  long *lp;

  /* `basefix' is used to avoid `if' tests in the integer scanner */
  static const short basefix[17] =
    {10, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16};

  nassigned = 0;
  nread = 0;
  for (;;)
    {
      c = *fmt++;
      if (c == 0)
	return nassigned;
      if (isspace (c))
	{
	  for (;;)
	    {
	      if (BufferEmpty)
		return nassigned;
	      if (!isspace (*fp->_p))
		break;
	      nread++, fp->_r--, fp->_p++;
	    }
	  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 (BufferEmpty)
	    goto input_failure;
	  if (*fp->_p != c)
	    goto match_failure;
	  fp->_r--, fp->_p++;
	  nread++;
	  continue;

	case '*':
	  flags |= SUPPRESS;
	  goto again;
	case 'l':
	  flags |= LONG;
	  goto again;
	case 'L':
	  /* not supported flags |= LONGDBL; */
	  goto again;
	case 'h':
	  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. Those marked `compat' are for
	   * 4.[123]BSD compatibility.
	   *
	   * (According to ANSI, E and X formats are supposed to
	   * the same as e and x.  Sorry about that.)
	   */

	case 'D':		/* compat */
	  flags |= LONG;
	  /* FALLTHROUGH */
	case 'd':
	  c = CT_INT;
	  ccfn = (u_long (*)(const char *_n, char **_end_PTR, int _base))strtol;
	  base = 10;
	  break;

	case 'i':
	  c = CT_INT;
	  ccfn = (u_long (*)(const char *_n, char **_end_PTR, int _base))strtol;
	  base = 0;
	  break;

	case 'O':		/* compat */
	  flags |= LONG;
	  /* FALLTHROUGH */
	case 'o':
	  c = CT_INT;
	  ccfn = (u_long (*)(const char *_n, char **_end_PTR, int _base))strtoul;
	  base = 8;
	  break;

	case 'u':
	  c = CT_INT;
	  ccfn = (u_long (*)(const char *_n, char **_end_PTR, int _base))strtoul;
	  base = 10;
	  break;

	case 'X':		/* compat   XXX */
	case 'x':
	  flags |= PFXOK;	/* enable 0x prefixing */
	  c = CT_INT;
	  ccfn = (u_long (*)(const char *_n, char **_end_PTR, int _base))strtoul;
	  base = 16;
	  break;

	case 'E':		/* compat   XXX */
	case 'G':		/* compat   XXX */
/* ANSI says that E,G and X behave the same way as e,g,x */
	  /* FALLTHROUGH */
	case 'e':
	case 'f':
	case 'g':
	  c = CT_FLOAT;
	  break;

	case 's':
	  c = CT_STRING;
	  break;

	case '[':
	  fmt = __sccl (ccltab, fmt);
	  flags |= NOSKIP;
	  c = CT_CCL;
	  break;

	case 'c':
	  flags |= NOSKIP;
	  c = CT_CHAR;
	  break;

	case 'p':		/* pointer format is like hex */
	  flags |= POINTER | PFXOK;
	  c = CT_INT;
	  ccfn = (u_long (*)(const char *_n, char **_end_PTR, int _base))strtoul;
	  base = 16;
	  break;

	case 'n':
	  if (flags & SUPPRESS)	/* ??? */
	    continue;
	  if (flags & SHORT)
	    {
	      sp = va_arg (ap, short *);
	      *sp = (short)nread;
	    }
	  else if (flags & LONG)
	    {
	      lp = va_arg (ap, long *);
	      *lp = nread;
	    }
	  else
	    {
	      ip = va_arg (ap, int *);
	      *ip = nread;
	    }
	  continue;

	  /*
	   * Disgusting backwards compatibility hacks.	XXX
	   */
	case '\0':		/* compat */
	  return EOF;

	default:		/* compat */
	  if (isupper (c))
	    flags |= LONG;
	  c = CT_INT;
	  ccfn = (u_long (*)(const char *_n, char **_end_PTR, int _base))strtol;
	  base = 10;
	  break;
	}

      /*
       * We have a conversion that requires input.
       */
      if (BufferEmpty)
	goto input_failure;

      /*
       * Consume leading white space, except for formats that
       * suppress this.
       */
      if ((flags & NOSKIP) == 0)
	{
	  while (isspace (*fp->_p))
	    {
	      nread++;
	      if (--fp->_r > 0)
		fp->_p++;
	      else
	      if (__srefill (fp))
		goto input_failure;
	    }
	  /*
	   * Note that there is at least one character in the
	   * buffer, so conversions that do not set NOSKIP ca
	   * no longer result in an input failure.
	   */
	}

      /*
       * Do the conversion.
       */
      switch (c)
	{

	case CT_CHAR:
	  /* scan arbitrary characters (sets NOSKIP) */
	  if (width == 0)
	    width = 1;
	  if (flags & SUPPRESS)
	    {
	      size_t sum = 0;

	      for (;;)
		{
		  if ((n = fp->_r) < (int)width)
		    {
		      sum += n;
		      width -= n;
		      fp->_p += n;
		      if (__srefill (fp))
			{
			  if (sum == 0)
			    goto input_failure;
			  break;
			}
		    }
		  else
		    {
		      sum += width;
		      fp->_r -= width;
		      fp->_p += width;
		      break;
		    }
		}
	      nread += sum;
	    }
	  else
	    {
	      size_t r = fread ((void*) va_arg (ap, char *), 1, width, fp);

	      if (r == 0)
		goto input_failure;
	      nread += r;
	      nassigned++;
	    }
	  break;

	case CT_CCL:
	  /* scan a (nonempty) character class (sets NOSKIP) */
	  if (width == 0)
	    width = (unsigned long)(~0);		/* `infinity' */
	  /* take only those things in the class */
	  if (flags & SUPPRESS)
	    {
	      n = 0;
	      while (ccltab[*fp->_p])
		{
		  n++, fp->_r--, fp->_p++;
		  if (--width == 0)
		    break;
		  if (BufferEmpty)
		    {
		      if (n == 0)
			goto input_failure;
		      break;
		    }
		}
	      if (n == 0)
		goto match_failure;
	    }
	  else
	    {
	      p0 = p = va_arg (ap, char *);
	      while (ccltab[*fp->_p])
		{
		  fp->_r--;
		  *p++ = *fp->_p++;
		  if (--width == 0)
		    break;
		  if (BufferEmpty)
		    {
		      if (p == p0)
			goto input_failure;
		      break;
		    }
		}
	      n = p - p0;
	      if (n == 0)
		goto match_failure;
	      *p = 0;
	      nassigned++;
	    }
	  nread += n;
	  break;

	case CT_STRING:
	  /* like CCL, but zero-length string OK, & no NOSKIP */
	  if (width == 0)
	    width = (unsigned long)(~0);
	  if (flags & SUPPRESS)
	    {
	      n = 0;
	      while (!isspace (*fp->_p))
		{
		  n++, fp->_r--, fp->_p++;
		  if (--width == 0)
		    break;
		  if (BufferEmpty)
		    break;
		}
	      nread += n;
	    }
	  else
	    {
	      p0 = p = va_arg (ap, char *);
	      while (!isspace (*fp->_p))
		{
		  fp->_r--;
		  *p++ = *fp->_p++;
		  if (--width == 0)
		    break;
		  if (BufferEmpty)
		    break;
		}
	      *p = 0;
	      nread += p - p0;
	      nassigned++;
	    }
	  continue;

	case CT_INT:
	  /* scan an integer as if by strtol/strtoul */
#ifdef hardway
	  if (width == 0 || width > sizeof (buf) - 1)
	    width = sizeof (buf) - 1;
#else
	  /* size_t is unsigned, hence this optimisation */
	  if (--width > sizeof (buf) - 2)
	    width = sizeof (buf) - 2;
	  width++;
#endif
	  flags |= SIGNOK | NDIGITS | NZDIGITS;
	  for (p = buf; width; width--)
	    {
	      c = *fp->_p;
	      /*
	       * 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;
		      goto ok;
		    }
		  break;

		  /* x ok iff flag still set & 2nd char */
		case 'x':
		case 'X':
		  if (flags & PFXOK && p == buf + 1)
		    {
		      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.
	       */
	      break;
	    ok:
	      /*
	       * c is legal: store it and look at the next.
	       */
	      *p++ = (char)c;
	      if (--fp->_r > 0)
		fp->_p++;
	      else
	      if (__srefill (fp))
		break;		/* EOF */
	    }
	  /*
	   * 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)
		(void) ungetc (*(u_char *)-- p, fp);
	      goto match_failure;
	    }
	  c = ((u_char *) p)[-1];
	  if (c == 'x' || c == 'X')
	    {
	      --p;
	      /*(void)*/ ungetc (c, fp);
	    }
	  if ((flags & SUPPRESS) == 0)
	    {
	      u_long res;

	      *p = 0;
	      res = (*ccfn) (buf, (char **) NULL, base);
	      if (flags & POINTER)
		*(va_arg (ap, void* *)) = (void*) res;
	      else if (flags & SHORT)
		{
		  sp = va_arg (ap, short *);
		  *sp = (short)res;
		}
	      else if (flags & LONG)
		{
		  lp = va_arg (ap, long *);
		  *lp = res;
		}
	      else
		{
		  ip = va_arg (ap, int *);
		  *ip = res;
		}
	      nassigned++;
	    }
	  nread += p - buf;
	  break;

	case CT_FLOAT:
	  /* scan a floating point number as if by strtod */
#ifdef hardway
	  if (width == 0 || width > sizeof (buf) - 1)
	    width = sizeof (buf) - 1;
#else
	  /* size_t is unsigned, hence this optimisation */
	  if (--width > sizeof (buf) - 2)
	    width = sizeof (buf) - 2;
	  width++;
#endif
	  flags |= SIGNOK | NDIGITS | DPTOK | EXPOK;
	  for (p = buf; width; width--)
	    {
	      c = *fp->_p;
	      /*
	       * This code mimicks the integer conversion
	       * code, but is much simpler.
	       */
	      switch (c)
		{

		case '0':
		case '1':
		case '2':
		case '3':
		case '4':
		case '5':
		case '6':
		case '7':
		case '8':
		case '9':
		  flags &= ~(SIGNOK | NDIGITS);
		  goto fok;

		case '+':
		case '-':
		  if (flags & SIGNOK)
		    {
		      flags &= ~SIGNOK;
		      goto fok;
		    }
		  break;
		case '.':
		  if (flags & DPTOK)
		    {
		      flags &= ~(SIGNOK | DPTOK);
		      goto fok;
		    }
		  break;
		case 'e':
		case 'E':
		  /* no exponent without some digits */
		  if ((flags & (NDIGITS | EXPOK)) == EXPOK)
		    {
		      flags =
			(flags & ~(EXPOK | DPTOK)) |
			SIGNOK | NDIGITS;
		      goto fok;
		    }
		  break;
		}
	      break;
	    fok:
	      *p++ = (char)c;
	      if (--fp->_r > 0)
		fp->_p++;
	      else
	      if (__srefill (fp))
		break;		/* EOF */
	    }
	  /*
	   * If no digits, might be missing exponent digits
	   * (just give back the exponent) or might be missing
	   * regular digits, but had sign and/or decimal point.
	   */
	  if (flags & NDIGITS)
	    {
	      if (flags & EXPOK)
		{
		  /* no digits at all */
		  while (p > buf)
		    ungetc (*(u_char *)-- p, fp);
		  goto match_failure;
		}
	      /* just a bad exponent (e and maybe sign) */
	      c = *(u_char *)-- p;
	      if (c != 'e' && c != 'E')
		{
		  (void) ungetc (c, fp);	/* sign */
		  c = *(u_char *)-- p;
		}
	      (void) ungetc (c, fp);
	    }
	  if ((flags & SUPPRESS) == 0)
	    {
	      double res;

	      *p = 0;
	      res = atof (buf);
	      if (flags & LONG)
		{
		  dp = va_arg (ap, double *);
		  *dp = res;
		}
	      else
		{
		  flp = va_arg (ap, float *);
		  *flp = (float)res;
		}
	      nassigned++;
	    }
	  nread += p - buf;
	  break;
	}
    }
input_failure:
  return nassigned ? nassigned : -1;
match_failure:
  return nassigned;
}

/*
 * Fill in the given table from the scanset at the given format
 * (just after `[').  Return a pointer to the character past the
 * closing `]'.  The table has a 1 wherever characters should be
 * considered part of the scanset.
 */

/*static*/
u_char *
__sccl (register char *tab,register u_char *fmt)
{
  register int c, n, v;

  /* first `clear' the whole table */
  c = *fmt++;			/* first char hat => negated scanset */
  if (c == '^')
    {
      v = 1;			/* default => accept */
      c = *fmt++;		/* get new first char */
    }
  else
    v = 0;			/* default => reject */
  /* should probably use memset here */
  for (n = 0; n < 256; n++)
    tab[n] = (char)v;
  if (c == 0)
    return fmt - 1;		/* format ended before closing ] */

  /*
   * Now set the entries corresponding to the actual scanset to the
   * opposite of the above.
   *
   * The first character may be ']' (or '-') without being special; the
   * last character may be '-'.
   */

  v = 1 - v;
  for (;;)
    {
      tab[c] = (char)v;		/* take character c */
    doswitch:
      n = *fmt++;		/* and examine the next */
      switch (n)
	{

	case 0:		/* format ended too soon */
	  return fmt - 1;

	case '-':
	  /*
	   * A scanset of the form [01+-] is defined as `the digit 0, the
	   * digit 1, the character +, the character -', but the effect of a
	   * scanset such as [a-zA-Z0-9] is implementation defined.  The V7
	   * Unix scanf treats `a-z' as `the letters a through z', but treats
	   * `a-a' as `the letter a, the character -, and the letter a'.
	   *
	   * For compatibility, the `-' is not considerd to define a range if
	   * the character following it is either a close bracket (required by
	   * ANSI) or is not numerically greater than the character we just
	   * stored in the table (c).
	   */
	  n = *fmt;
	  if (n == ']' || n < c)
	    {
	      c = '-';
	      break;		/* resume the for(;;) */
	    }
	  fmt++;
	  do
	    {			/* fill in the range */
	      tab[++c] = (char)v;
	    }
	  while (c < n);
#if 1			/* XXX another disgusting compatibility hack */
	  /*
	   * Alas, the V7 Unix scanf also treats formats such
	   * as [a-c-e] as `the letters a through e'. This too
	   * is permitted by the standard....
	   */
	  goto doswitch;
#else
	  c = *fmt++;
	  if (c == 0)
	    return fmt - 1;
	  if (c == ']')
	    return fmt;

	  break;
#endif

	case ']':		/* end of scanset */
	  return fmt;

	default:		/* just another character */
	  c = n;
	  break;
	}
    }
  /* NOTREACHED */
}
