text: #include <stdio.h>
  #include <stdlib.h>
  #include <stdarg.h>
  #include <ctype.h>
  #include <wchar.h>
  #include <wctype.h>
  #include <limits.h>
  #include <string.h>
  #include <errno.h>
  #include <math.h>
  #include <float.h>
  
  #include "stdio_impl.h"
  #include "shgetc.h"
  #include "intscan.h"
  #include "floatscan.h"
  #include "libc.h"
  
  #define SIZE_hh -2
  #define SIZE_h  -1
  #define SIZE_def 0
  #define SIZE_l   1
  #define SIZE_L   2
  #define SIZE_ll  3
  
  static void store_int(void *dest, int size, unsigned long long i)
  {
  	if (!dest) return;
  	switch (size) {
  	case SIZE_hh:
  		*(char *)dest = i;
  		break;
  	case SIZE_h:
  		*(short *)dest = i;
  		break;
  	case SIZE_def:
  		*(int *)dest = i;
  		break;
  	case SIZE_l:
  		*(long *)dest = i;
  		break;
  	case SIZE_ll:
  		*(long long *)dest = i;
  		break;
  	}
  }
  
  static void *arg_n(va_list ap, unsigned int n)
  {
  	void *p;
  	unsigned int i;
  	va_list ap2;
  	va_copy(ap2, ap);
  	for (i=n; i>1; i--) va_arg(ap2, void *);
  	p = va_arg(ap2, void *);
  	va_end(ap2);
  	return p;
  }
  
  static int in_set(const wchar_t *set, int c)
  {
  	int j;
  	const wchar_t *p = set;
  	if (*p == '-') {
  		if (c=='-') return 1;
  		p++;
  	} else if (*p == ']') {
  		if (c==']') return 1;
  		p++;
  	}
  	for (; *p && *p != ']'; p++) {
  		if (*p=='-' && p[1] && p[1] != ']')
  			for (j=p++[-1]; j<*p; j++)
  				if (c==j) return 1;
  		if (c==*p) return 1;
  	}
  	return 0;
  }
  
  #if 1
  #undef getwc
  #define getwc(f) \
  	((f)->rpos < (f)->rend && *(f)->rpos < 128 ? *(f)->rpos++ : (getwc)(f))
  
  #undef ungetwc
  #define ungetwc(c,f) \
  	((f)->rend && (c)<128U ? *--(f)->rpos : ungetwc((c),(f)))
  #endif
  
  int vfwscanf(FILE *restrict f, const wchar_t *restrict fmt, va_list ap)
  {
  	int width;
  	int size;
  	int alloc;
  	const wchar_t *p;
  	int c, t;
  	char *s;
  	wchar_t *wcs;
  	void *dest=NULL;
  	int invert;
  	int matches=0;
  	off_t pos = 0, cnt;
  	static const char size_pfx[][3] = { "hh", "h", "", "l", "L", "ll" };
  	char tmp[3*sizeof(int)+10];
  	const wchar_t *set;
  	size_t i, k;
  
  	FLOCK(f);
  
  	for (p=fmt; *p; p++) {
  
  		alloc = 0;
  
  		if (iswspace(*p)) {
  			while (iswspace(p[1])) p++;
  			while (iswspace((c=getwc(f)))) pos++;
  			ungetwc(c, f);
  			continue;
  		}
  		if (*p != '%' || p[1] == '%') {
  			p += *p=='%';
  			c = getwc(f);
  			if (c!=*p) {
  				ungetwc(c, f);
  				if (c<0) goto input_fail;
  				goto match_fail;
  			}
  			pos++;
  			continue;
  		}
  
  		p++;
  		if (*p=='*') {
  			dest = 0; p++;
  		} else if (iswdigit(*p) && p[1]=='$') {
  			dest = arg_n(ap, *p-'0'); p+=2;
  		} else {
  			dest = va_arg(ap, void *);
  		}
  
  		for (width=0; iswdigit(*p); p++) {
  			width = 10*width + *p - '0';
  		}
  
  		if (*p=='m') {
  			alloc = !!dest;
  			p++;
  		} else {
  			alloc = 0;
  		}
  
  		size = SIZE_def;
  		switch (*p++) {
  		case 'h':
  			if (*p == 'h') p++, size = SIZE_hh;
  			else size = SIZE_h;
  			break;
  		case 'l':
  			if (*p == 'l') p++, size = SIZE_ll;
  			else size = SIZE_l;
  			break;
  		case 'j':
  			size = SIZE_ll;
  			break;
  		case 'z':
  		case 't':
  			size = SIZE_l;
  			break;
  		case 'L':
  			size = SIZE_L;
  			break;
  		case 'd': case 'i': case 'o': case 'u': case 'x':
  		case 'a': case 'e': case 'f': case 'g':
  		case 'A': case 'E': case 'F': case 'G': case 'X':
  		case 's': case 'c': case '[':
  		case 'S': case 'C':
  		case 'p': case 'n':
  			p--;
  			break;
  		default:
  			goto fmt_fail;
  		}
  
  		t = *p;
  
  		/* Transform S,C -> ls,lc */
  		if ((t&0x2f)==3) {
  			size = SIZE_l;
  			t |= 32;
  		}
  
  		if (t != 'n') {
  			if (t != '[' && (t|32) != 'c')
  				while (iswspace((c=getwc(f)))) pos++;
  			else
  				c=getwc(f);
  			if (c < 0) goto input_fail;
  			ungetwc(c, f);
  		}
  
  		switch (t) {
  		case 'n':
  			store_int(dest, size, pos);
  			/* do not increment match count, etc! */
  			continue;
  
  		case 's':
  		case 'c':
  		case '[':
  			if (t == 'c') {
  				if (width<1) width = 1;
  				invert = 1;
  				set = L"";
  			} else if (t == 's') {
  				invert = 1;
  				set = (const wchar_t[]){
  					' ', '\t', '\n', '\r', 11, 12,  0x0085,
  					0x2000, 0x2001, 0x2002, 0x2003, 0x2004, 0x2005,
  					0x2006, 0x2008, 0x2009, 0x200a,
  					0x2028, 0x2029, 0x205f, 0x3000, 0 };
  			} else {
  				if (*++p == '^') p++, invert = 1;
  				else invert = 0;
  				set = p;
  				if (*p==']') p++;
  				while (*p!=']') {
  					if (!*p) goto fmt_fail;
  					p++;
  				}
  			}
  
  			s = (size == SIZE_def) ? dest : 0;
  			wcs = (size == SIZE_l) ? dest : 0;
  
  			int gotmatch = 0;
  
  			if (width < 1) width = -1;
  
  			i = 0;
  			if (alloc) {
  				k = t=='c' ? width+1U : 31;
  				if (size == SIZE_l) {
  					wcs = malloc(k*sizeof(wchar_t));
  					if (!wcs) goto alloc_fail;
  				} else {
  					s = malloc(k);
  					if (!s) goto alloc_fail;
  				}
  			}
  			while (width) {
  				if ((c=getwc(f))<0) break;
  				if (in_set(set, c) == invert)
  					break;
  				if (wcs) {
  					wcs[i++] = c;
  					if (alloc && i==k) {
  						k += k+1;
  						wchar_t *tmp = realloc(wcs, k*sizeof(wchar_t));
  						if (!tmp) goto alloc_fail;
  						wcs = tmp;
  					}
  				} else if (size != SIZE_l) {
  					int l = wctomb(s?s+i:tmp, c);
  					if (l<0) goto input_fail;
  					i += l;
  					if (alloc && i > k-4) {
  						k += k+1;
  						char *tmp = realloc(s, k);
  						if (!tmp) goto alloc_fail;
  						s = tmp;
  					}
  				}
  				pos++;
  				width-=(width>0);
  				gotmatch=1;
  			}
  			if (width) {
  				ungetwc(c, f);
  				if (t == 'c' || !gotmatch) goto match_fail;
  			}
  
  			if (alloc) {
  				if (size == SIZE_l) *(wchar_t **)dest = wcs;
  				else *(char **)dest = s;
  			}
  			if (t != 'c') {
  				if (wcs) wcs[i] = 0;
  				if (s) s[i] = 0;
  			}
  			break;
  
  		case 'd': case 'i': case 'o': case 'u': case 'x':
  		case 'a': case 'e': case 'f': case 'g':
  		case 'A': case 'E': case 'F': case 'G': case 'X':
  		case 'p':
  			if (width < 1) width = 0;
  			snprintf(tmp, sizeof tmp, "%.*s%.0d%s%c%%lln",
  				1+!dest, "%*", width, size_pfx[size+2], t);
  			cnt = 0;
  			if (fscanf(f, tmp, dest?dest:&cnt, &cnt) == -1)
  				goto input_fail;
  			else if (!cnt)
  				goto match_fail;
  			pos += cnt;
  			break;
  		default:
  			goto fmt_fail;
  		}
  
  		if (dest) matches++;
  	}
  	if (0) {
  fmt_fail:
  alloc_fail:
  input_fail:
  		if (!matches) matches--;
  match_fail:
  		if (alloc) {
  			free(s);
  			free(wcs);
  		}
  	}
  	FUNLOCK(f);
  	return matches;
  }
  
  weak_alias(vfwscanf,__isoc99_vfwscanf);
  