#include	"sfhdr.h"

/*	The main engine for reading formatted data
**
**	Written by Kiem-Phong Vo.
*/

#define MAXWIDTH	(int)(((uint)~0)>>1)	/* max amount to scan	*/

#if __STD_C
static char* setclass(reg char* form, reg char* accept)
#else
static char* setclass(form,accept)
reg char*	form;	/* format string			*/
reg char*	accept;	/* accepted characters are set to 1	*/
#endif
{
	reg int		fmt, c, yes;

	if((fmt = *form++) == '^')
	{	/* we want the complement of this set */
		yes = 0;
		fmt = *form++;
	}
	else	yes = 1;

	for(c = 0; c <= SF_MAXCHAR; ++c)
		accept[c] = !yes;

	if(fmt == ']' || fmt == '-')
	{	/* special first char */
		accept[fmt] = yes;
		fmt = *form++;
	}

	for(; fmt != ']'; fmt = *form++)
	{	/* done */
		if(!fmt)
			return (form-1);

		/* interval */
		if(fmt != '-' || form[0] == ']' || form[-2] > form[0])
			accept[fmt] = yes;
		else for(c = form[-2]+1; c < form[0]; ++c)
			accept[c] = yes;
	}

	return form;
}

#if __STD_C
static void _sfbuf(Sfio_t* f, int* rs)
#else
static void _sfbuf(f, rs)
Sfio_t*	f;
int*	rs;
#endif
{
	if(f->next >= f->endb)
	{	if(*rs > 0)	/* try peeking for a share stream if possible */
		{	f->mode |= SF_RV;
			if(SFFILBUF(f,-1) > 0)
			{	f->mode |= SF_PEEK;
				return;
			}
			*rs = -1;	/* can't peek, back to normal reads */
		}
		(void)SFFILBUF(f,-1);
	}
}

#if __STD_C
int sfvscanf(Sfio_t* f, reg const char* form, va_list args)
#else
int sfvscanf(f,form,args)
Sfio_t*		f;		/* file to be scanned */
reg char*	form;		/* scanning format */
va_list		args;
#endif
{
	reg uchar	*d, *endd, *data;
	reg int		inp, shift, base, width;
	ssize_t		size;
	int		fmt, flags, dot, n_assign, v, n, n_input;
	char*		sp;
	char		accept[SF_MAXDIGITS];

	Argv_t		argv;
	Sffmt_t		*ft;
	Fmt_t		*fm, *fmstk;

	Fmtpos_t*	fp;
	char		*oform;
	va_list		oargs;
	int		argp, argn;

	Void_t*		value;	/* location to assign scanned value */
	char*		t_str;
	ssize_t		n_str;
	int		rs = (f->extent < 0 && (f->flags&SF_SHARE)) ? 1 : 0;

#define SFBUF(f)	(_sfbuf(f,&rs), (data = d = f->next), (endd = f->endb) )
#define SFLEN(f)	(d-data)
#define SFEND(f)	((n_input += d-data), \
			 (rs > 0 ? SFREAD(f,(Void_t*)data,d-data) : ((f->next = d), 0)) )
#define SFGETC(f,c)	((c) = (d < endd || (SFEND(f), SFBUF(f), d < endd)) ? \
				(int)(*d++) : -1 )
#define SFUNGETC(f,c)	(--d)

	SFMTXSTART(f,-1);

	if(f->mode != SF_READ && _sfmode(f,SF_READ,0) < 0)
		SFMTXRETURN(f, -1);
	SFLOCK(f,0);

	SFCVINIT();	/* initialize conversion tables */

	SFBUF(f);
	n_assign = n_input = 0;

	inp = -1;

	fmstk = NIL(Fmt_t*); ft = NIL(Sffmt_t*);

	fp = NIL(Fmtpos_t*); argn = -1;
	oform = (char*)form; va_copy(oargs,args);

loop_fmt :
	while((fmt = *form++) )
	{	if(fmt != '%')
		{	if(isspace(fmt))
			{	if(fmt != '\n' || !(f->flags&SF_LINE))
					fmt = -1;
				for(;;)
				{	if(SFGETC(f,inp) < 0 || inp == fmt)
						goto loop_fmt;
					else if(!isspace(inp))
					{	SFUNGETC(f,inp);
						goto loop_fmt;
					}
				}
			}
			else
			{ match_1:
				if(SFGETC(f,inp) != fmt)
				{	if(inp >= 0)
						SFUNGETC(f,inp);
					goto pop_fmt;
				}
			}
			continue;
		}

		if(*form == '%')
		{	form += 1;
			goto match_1;
		}

		if(*form == '\0')
			goto pop_fmt;

		if(*form == '*')
		{	flags = SFFMT_SKIP;
			form += 1;
		}
		else	flags = 0;

		/* matching some pattern */
		base = 10; size = -1;
		width = dot = 0;
		t_str = NIL(char*); n_str = 0;
		value = NIL(Void_t*);
		argp = -1;

	loop_flags:	/* LOOP FOR FLAGS, WIDTH, BASE, TYPE */
		switch((fmt = *form++) )
		{
		case LEFTP : /* get the type which is enclosed in balanced () */
			t_str = (char*)form;
			for(v = 1;;)
			{	switch(*form++)
				{
				case 0 :	/* not balanceable, retract */
					form = t_str;
					t_str = NIL(char*);
					n_str = 0;
					goto loop_flags;
				case LEFTP :	/* increasing nested level */
					v += 1;
					continue;
				case RIGHTP :	/* decreasing nested level */
					if((v -= 1) != 0)
						continue;
					if(*t_str != '*' )
						n_str = (form-1) - t_str;
					else
					{	t_str = (*_Sffmtintf)(t_str+1,&n);
						if(*t_str == '$')
						{	if(!fp &&
							   !(fp = (*_Sffmtposf)
								  (f,oform,oargs,1)) )
								goto pop_fmt;
							n = FP_SET(n,argn);
						}
						else	n = FP_SET(-1,argn);

						if(fp)
						{	t_str = fp[n].argv.s;
							n_str = fp[n].ft.size;
						}
						else if(ft && ft->extf )
						{	FMTSET(ft, form,args,
								LEFTP, 0, 0, 0,0,0,
								NIL(char*),0);
							n = (*ft->extf)
							      (f,(Void_t*)&argv,ft);
							if(n < 0)
								goto pop_fmt;
							if(!(ft->flags&SFFMT_VALUE) )
								goto t_arg;
							if((t_str = argv.s) &&
							   (n_str = (int)ft->size) < 0)
								n_str = strlen(t_str);
						}
						else
						{ t_arg:
							if((t_str = va_arg(args,char*)) )
								n_str = strlen(t_str);
						}
					}
					goto loop_flags;
				}
			}

		case '#' : /* alternative format */
			flags |= SFFMT_ALTER;
			goto loop_flags;

		case '.' : /* width & base */
			dot += 1;
			if(isdigit(*form))
			{	fmt = *form++;
				goto dot_size;
			}
			else if(*form == '*')
			{	form = (*_Sffmtintf)(form+1,&n);
				if(*form == '$')
				{	form += 1;
					if(!fp && !(fp = (*_Sffmtposf)(f,oform,oargs,1)) )
						goto pop_fmt;
					n = FP_SET(n,argn);
				}
				else	n = FP_SET(-1,argn);

				if(fp)
					v = fp[n].argv.i;
				else if(ft && ft->extf )
				{	FMTSET(ft, form,args, '.',dot, 0, 0,0,0,
						NIL(char*), 0);
					if((*ft->extf)(f, (Void_t*)(&argv), ft) < 0)
						goto pop_fmt;
					if(ft->flags&SFFMT_VALUE)
						v = argv.i;
					else	v = (dot <= 2) ? va_arg(args,int) : 0;
				}
				else	v = (dot <= 2) ? va_arg(args,int) : 0;
				if(v < 0)
					v = 0;
				goto dot_set;
			}
			else	goto loop_flags;
			
		case '0' : case '1' : case '2' : case '3' : case '4' :
		case '5' : case '6' : case '7' : case '8' : case '9' :
		dot_size :
			for(v = fmt-'0'; isdigit(*form); ++form)
				v = v*10 + (*form - '0');

			if(*form == '$')
			{	form += 1;
				if(!fp && !(fp = (*_Sffmtposf)(f,oform,oargs,1)) )
					goto pop_fmt;
				argp = v-1;
				goto loop_flags;
			}

		dot_set :
			if(dot == 0 || dot == 1)
				width = v;
			else if(dot == 2)
				base = v;
			goto loop_flags;

		case 'I' : /* object size */
			size = 0;
			flags = (flags & ~SFFMT_TYPES) | SFFMT_IFLAG;
			if(isdigit(*form))
			{	for(n = *form; isdigit(n); n = *++form)
					size = size*10 + (n - '0');
			}
			else if(*form == '*')
			{	form = (*_Sffmtintf)(form+1,&n);
				if(*form == '$')
				{	form += 1;
					if(!fp && !(fp = (*_Sffmtposf)(f,oform,oargs,1)))
						goto pop_fmt;
					n = FP_SET(n,argn);
				}
				else	n = FP_SET(-1,argn);

				if(fp)	/* use position list */
					size = fp[n].argv.i;
				else if(ft && ft->extf )
				{	FMTSET(ft, form,args, 'I',sizeof(int), 0, 0,0,0,
						NIL(char*), 0);
					if((*ft->extf)(f, (Void_t*)(&argv), ft) < 0)
						goto pop_fmt;
					if(ft->flags&SFFMT_VALUE)
						size = argv.i;
					else	size = va_arg(args,int);
				}
				else	size = va_arg(args,int);
			}
			goto loop_flags;

		case 'l' :
			size = -1;
			flags &= ~SFFMT_TYPES;
			if(*form == 'l')
			{	form += 1;
				flags |= SFFMT_LLONG;
			}
			else	flags |= SFFMT_LONG;
			goto loop_flags;
		case 'h' :
			size = -1;
			flags &= ~SFFMT_TYPES;
			if(*form == 'h')
			{	form += 1;
				flags |= SFFMT_SSHORT;
			}
			else	flags |= SFFMT_SHORT;
			goto loop_flags;
		case 'L' :
			size = -1;
			flags = (flags&~SFFMT_TYPES) | SFFMT_LDOUBLE;
			goto loop_flags;
		case 'j' :
			size = -1;
			flags = (flags&~SFFMT_TYPES) | SFFMT_JFLAG;
			goto loop_flags;
		case 'z' :
			size = -1;
			flags = (flags&~SFFMT_TYPES) | SFFMT_ZFLAG;
			goto loop_flags;
		case 't' :
			size = -1;
			flags = (flags&~SFFMT_TYPES) | SFFMT_TFLAG;
			goto loop_flags;
		}

		/* set object size */
		if(flags & (SFFMT_TYPES & ~SFFMT_IFLAG) )
		{	if((_Sftype[fmt]&(SFFMT_INT|SFFMT_UINT)) || fmt == 'n')
			{	size =	(flags&SFFMT_LLONG) ? sizeof(Sflong_t) :
					(flags&SFFMT_LONG) ? sizeof(long) :
					(flags&SFFMT_SHORT) ? sizeof(short) :
					(flags&SFFMT_SSHORT) ? sizeof(char) :
					(flags&SFFMT_JFLAG) ? sizeof(Sflong_t) :
					(flags&SFFMT_TFLAG) ? sizeof(ptrdiff_t) :
					(flags&SFFMT_ZFLAG) ? sizeof(size_t) :
					-1;
			}
			else if(_Sftype[fmt]&SFFMT_FLOAT)
			{	size = (flags&SFFMT_LDOUBLE) ? sizeof(Sfdouble_t) :
				       (flags&(SFFMT_LONG|SFFMT_LLONG)) ?
						sizeof(double) : -1;
			}
		}

		argp = FP_SET(argp,argn);
		if(fp)
		{	if(!(fp[argp].ft.flags&SFFMT_SKIP) )
			{	n_assign += 1;
				value = fp[argp].argv.vp;
				size = fp[argp].ft.size;
				if(ft && ft->extf && fp[argp].ft.fmt != fp[argp].fmt)
					fmt = fp[argp].ft.fmt;
			}
			else	flags |= SFFMT_SKIP;
		}
		else if(ft && ft->extf)
		{	FMTSET(ft, form,args, fmt, size,flags, width,0,base, t_str,n_str);
			SFEND(f); SFOPEN(f,0);
			v = (*ft->extf)(f, (Void_t*)&argv, ft);
			SFLOCK(f,0); SFBUF(f);

			if(v < 0)
				goto pop_fmt;
			else if(v == 0) /* extf did not use input stream */
			{	FMTGET(ft, form,args, fmt, size, flags, width,n,base);
				if((ft->flags&SFFMT_VALUE) && !(ft->flags&SFFMT_SKIP) )
					value = argv.vp;
			}
			else /* v > 0: number of input bytes consumed */
			{	n_input += v;
				if(!(ft->flags&SFFMT_SKIP) )
					n_assign += 1;
				continue;
			}
		}

		if(_Sftype[fmt] == 0) /* unknown pattern */
			continue;

		/* get the address to assign value */
		if(!value && !(flags&SFFMT_SKIP) )
			value = va_arg(args,Void_t*);

		if(*form == '!')
		{	form += 1;
			if(!fp)
				fp = (*_Sffmtposf)(f,oform,oargs,1);
			else	goto pop_fmt;

			if(!(argv.ft = va_arg(args,Sffmt_t*)) )
				continue;
			if(!argv.ft->form && ft ) /* change extension functions */
			{	if(ft->eventf &&
				   (*ft->eventf)(f,SF_DPOP,(Void_t*)form,ft) < 0)
					continue;
				fmstk->ft = ft = argv.ft;
			}
			else			/* stack a new environment */
			{	if(!(fm = (Fmt_t*)malloc(sizeof(Fmt_t))) )
					goto done;

				if(argv.ft->form)
				{	fm->form = (char*)form;
					va_copy(fm->args,args);

					fm->oform = oform;
					va_copy(fm->oargs,oargs);
					fm->argn = argn;
					fm->fp = fp;

					form = argv.ft->form;	
					va_copy(args,argv.ft->args);
					argn = -1;
					fp = NIL(Fmtpos_t*);
				}
				else	fm->form = NIL(char*);

				fm->eventf = argv.ft->eventf;
				fm->ft = ft;
				fm->next = fmstk;
				fmstk = fm;
				ft = argv.ft;
			}
			continue;
		}

		if(fmt == 'n') /* return length of consumed input */
		{
#if !_ast_intmax_long
			if(FMTCMP(size,Sflong_t,Sflong_t))
				*((Sflong_t*)value) = (Sflong_t)(n_input+SFLEN(f));
			else
#endif
			if(sizeof(long) > sizeof(int) && FMTCMP(size,long,Sflong_t))
				*((long*)value) = (long)(n_input+SFLEN(f));
			else if(sizeof(short) < sizeof(int) &&
				FMTCMP(size,short,Sflong_t))
				*((short*)value) = (short)(n_input+SFLEN(f));
			else if(size == sizeof(char))
				*((char*)value) = (char)(n_input+SFLEN(f));
			else	*((int*)value) = (int)(n_input+SFLEN(f));
			continue;
		}

		/* if get here, start scanning input */
		if(width == 0)
			width = fmt == 'c' ? 1 : MAXWIDTH;

		/* define the first input character */
		if(fmt == 'c' || fmt == '[')
			SFGETC(f,inp);
		else
		{	do	{ SFGETC(f,inp); }
			while(isspace(inp))	/* skip starting blanks */
				;
		}
		if(inp < 0)
			goto done;

		if(_Sftype[fmt] == SFFMT_FLOAT)
		{	reg char*	val;
			reg int		dot, exponent;

			val = accept;
			if(width >= SF_MAXDIGITS)
				width = SF_MAXDIGITS-1;
			dot = exponent = 0;
			do
			{	if(isdigit(inp))
					*val++ = inp;
				else if(inp == '.')
				{	/* too many dots */
					if(dot++ > 0)
						break;
					*val++ = '.';
				}
				else if(inp == 'e' || inp == 'E')
				{	/* too many e,E */
					if(exponent++ > 0)
						break;
					*val++ = inp;
					if(--width <= 0 || SFGETC(f,inp) < 0 ||
					   (inp != '-' && inp != '+' && !isdigit(inp)) )
						break;
					*val++ = inp;
				}
				else if(inp == '-' || inp == '+')
				{	/* too many signs */
					if(val > accept)
						break;
					*val++ = inp;
				}
				else	break;

			} while(--width > 0 && SFGETC(f,inp) >= 0);

			if(value)
			{	*val = '\0';
#if !_ast_fltmax_double
				if(FMTCMP(size,Sfdouble_t,Sfdouble_t))
					argv.ld = _sfstrtod(accept,NIL(char**));
				else
#endif
					argv.d = (double)strtod(accept,NIL(char**));
			}

			if(value)
			{	n_assign += 1;
#if !_ast_fltmax_double
				if(FMTCMP(size,Sfdouble_t,Sfdouble_t))
					*((Sfdouble_t*)value) = argv.ld;
				else
#endif
				if(FMTCMP(size,double,Sfdouble_t))
					*((double*)value) = argv.d;
				else	*((float*)value) = (float)argv.d;
			}
		}
		else if(_Sftype[fmt] == SFFMT_UINT || fmt == 'p')
		{	if(inp == '-')
			{	SFUNGETC(f,inp);
				goto pop_fmt;
			}
			else	goto int_cvt;
		}
		else if(_Sftype[fmt] == SFFMT_INT)
		{ int_cvt:
			if(inp == '-' || inp == '+')
			{	if(inp == '-')
					flags |= SFFMT_MINUS;
				while(--width > 0 && SFGETC(f,inp) >= 0)
					if(!isspace(inp))
						break;
			}
			if(inp < 0)
				goto done;

			if(fmt == 'o')
				base = 8;
			else if(fmt == 'x' || fmt == 'p')
				base = 16;
			else if(fmt == 'i' && inp == '0') /* self-described data */
			{	base = 8;
				if(width > 1) /* peek to see if it's a base-16 */
				{	if(SFGETC(f,inp) >= 0)
					{	if(inp == 'x' || inp == 'X')
							base = 16;
						SFUNGETC(f,inp);
					}
					inp = '0';
				}
			}

			/* now convert */
			argv.lu = 0;
			if(base == 16)
			{	sp = (char*)_Sfcv36;
				shift = 4;
				if(sp[inp] >= 16)
				{	SFUNGETC(f,inp);
					goto pop_fmt;
				}
				if(inp == '0' && --width > 0)
				{	/* skip leading 0x or 0X */
					if(SFGETC(f,inp) >= 0 &&
					   (inp == 'x' || inp == 'X') && --width > 0)
						SFGETC(f,inp);
				}
				if(inp >= 0 && sp[inp] < 16)
					goto base_shift;
			}
			else if(base == 10)
			{	/* fast base 10 conversion */
				if(inp < '0' || inp > '9')
				{	SFUNGETC(f,inp);
					goto pop_fmt;
				}

				do
				{ argv.lu = (argv.lu<<3) + (argv.lu<<1) + (inp-'0');
				} while(--width > 0 &&
				        SFGETC(f,inp) >= '0' && inp <= '9');

				if(fmt == 'i' && inp == '#' && !(flags&SFFMT_ALTER) )
				{	base = (int)argv.lu;
					if(base < 2 || base > SF_RADIX)
						goto pop_fmt;
					argv.lu = 0;
					sp = base <= 36 ? (char*)_Sfcv36 : (char*)_Sfcv64;
					if(--width > 0 &&
					   SFGETC(f,inp) >= 0 && sp[inp] < base)
						goto base_conv;
				}
			}
			else
			{	/* other bases */
				sp = base <= 36 ? (char*)_Sfcv36 : (char*)_Sfcv64;
				if(base < 2 || base > SF_RADIX || sp[inp] >= base)
				{	SFUNGETC(f,inp);
					goto pop_fmt;
				}

			base_conv: /* check for power of 2 conversions */
				if((base & ~(base-1)) == base)
				{	if(base < 8)
						shift = base <  4 ? 1 : 2;
					else if(base < 32)
						shift = base < 16 ? 3 : 4;
					else	shift = base < 64 ? 5 : 6;

			base_shift:	do
					{ argv.lu = (argv.lu << shift) + sp[inp];
					} while(--width > 0 &&
					        SFGETC(f,inp) >= 0 && sp[inp] < base);
				}
				else
				{	do
					{ argv.lu = (argv.lu * base) + sp[inp];
					} while(--width > 0 &&
						SFGETC(f,inp) >= 0 && sp[inp] < base);
				}
			}

			if(flags&SFFMT_MINUS)
				argv.ll = -argv.ll;

			if(value)
			{	n_assign += 1;

				if(fmt == 'p')
#if _more_void_int
					*((Void_t**)value) = (Void_t*)((ulong)argv.lu);
#else
					*((Void_t**)value) = (Void_t*)((uint)argv.lu);
#endif
#if !_ast_intmax_long
				else if(FMTCMP(size,Sflong_t,Sflong_t))
					*((Sflong_t*)value) = argv.ll;
#endif
				else if(sizeof(long) > sizeof(int) &&
					FMTCMP(size,long,Sflong_t))
				{	if(fmt == 'd' || fmt == 'i')
						*((long*)value) = (long)argv.ll;
					else	*((ulong*)value) = (ulong)argv.lu;
				}
				else if(sizeof(short) < sizeof(int) &&
					FMTCMP(size,short,Sflong_t))
				{	if(fmt == 'd' || fmt == 'i')
						*((short*)value) = (short)argv.ll;
					else	*((ushort*)value) = (ushort)argv.lu;
				}
				else if(size == sizeof(char) )
				{	if(fmt == 'd' || fmt == 'i')
						*((char*)value) = (char)argv.ll;
					else	*((uchar*)value) = (uchar)argv.lu;
				}
				else
				{	if(fmt == 'd' || fmt == 'i')
						*((int*)value) = (int)argv.ll;
					else	*((uint*)value) = (uint)argv.lu;
				}
			}
		}
		else if(fmt == 's' || fmt == 'c' || fmt == '[')
		{	if(size < 0)
				size = MAXWIDTH;
			if(value)
			{	argv.s = (char*)value;
				if(fmt != 'c')
					size -= 1;
			}
			else	size = 0;

			n = 0;
			if(fmt == 's')
			{	do
				{	if(isspace(inp))
						break;
					if((n += 1) <= size)
						*argv.s++ = inp;
				} while(--width > 0 && SFGETC(f,inp) >= 0);
			}
			else if(fmt == 'c')
			{	do
				{	if((n += 1) <= size)
						*argv.s++ = inp;
				} while(--width > 0 && SFGETC(f,inp) >= 0);
			}
			else /* if(fmt == '[') */
			{	form = setclass((char*)form,accept);
				do
				{	if(!accept[inp])
					{	if(n > 0 || (flags&SFFMT_ALTER) )
							break;
						else
						{	SFUNGETC(f,inp);
							goto pop_fmt;
						}
					}
					if((n += 1) <= size)
						*argv.s++ = inp;
				} while(--width > 0 && SFGETC(f,inp) >= 0);
			}

			if(value && (n > 0 || fmt == '[') )
			{	n_assign += 1;
				if(fmt != 'c' && size >= 0)
					*argv.s = '\0';
			}
		}

		if(width > 0 && inp >= 0)
			SFUNGETC(f,inp);
	}

pop_fmt:
	if(fp)
	{	free(fp);
		fp = NIL(Fmtpos_t*);
	}
	while((fm = fmstk) ) /* pop the format stack and continue */
	{	if(fm->eventf)
		{	if(!form || !form[0])
				(*fm->eventf)(f,SF_FINAL,NIL(Void_t*),ft);
			else if((*fm->eventf)(f,SF_DPOP,(Void_t*)form,ft) < 0)
				goto loop_fmt;
		}

		fmstk = fm->next;
		if((form = fm->form) )
		{	va_copy(args, fm->args);
			oform = fm->oform;
			va_copy(oargs,fm->oargs);
			argn = fm->argn;
			fp = fm->fp;
		}
		ft = fm->ft;
		free(fm);
		if(form && form[0])
			goto loop_fmt;
	}

done:
	if(fp)
		free(fp);
	while((fm = fmstk) )
	{	if(fm->eventf)
			(*fm->eventf)(f,SF_FINAL,NIL(Void_t*),fm->ft);
		fmstk = fm->next;
		free(fm);
	}

	SFEND(f);
	SFOPEN(f,0);

	if(n_assign == 0 && inp < 0)
		n_assign = -1;

	SFMTXRETURN(f,n_assign);
}