/* sscanf.c: Replacement of sscanf for TI-Nspire
 * 
 * Copyright (C) 2013 by Yogeshwar Velingker, under the GNU General Public
 * License. No warranty. See COPYING for details.
 */

#ifdef	_TINSPIRE
#include <os.h>
#include "defs.h"
#include "sscanf.h"

/* Checks if char c is in first n bytes of the memory pointed to by mem.
 */
static int chr_in_mem(const char *mem, char c, size_t n)
{
    size_t	i;
    for (i = 0; i < n; i++) {
	if (*mem == c)
	    return TRUE;
	mem++;
    }
    
    return FALSE;
}

/* Simple sscanf for the purpose of this program.
 */
int simplesscanf(const char *str, const char *format, ...)
{
    va_list		ap;
    const char	       *f = format;
    const char	       *s = str;
    char	       *charp = NULL;
    int		       *intp = NULL;
    unsigned long      *longp = NULL;
    int			count = 0;
    size_t		loop;
    int			bracket_chars;
    unsigned int	field_width;
    int			scanset_negated;
    int			store_value;
    int			hex_use_long;
    
    va_start(ap, format);
    
    if (*f != '%' && !isspace(*f) && isspace(*s))
	return 0;
    
    while (*f != '\0') {
	while (isspace(*f))
	    f++;
	if (!(*f == '%' && (*(f + 1) == '[' || (*(f + 1) == '*'
	    && *(f + 2) == '[')))) {
	    while (isspace(*s))
		s++;
	} else if (isspace(*(f - 1))) {
	    while (isspace(*s))
		s++;
	}
	
	if (*f == '%') {
	    store_value = TRUE;
	    f++;
	    if (*f == '*') {
		store_value = FALSE;
		f++;
	    }
	    
	    if (*f == '%') {
		if (*s != '%')
		    break;
	    } else if (*f == 's') {
		if (*s == '\0') {
		    if (count == 0)
			return EOF;
		    else break;
		}
		if (store_value)
		    charp = va_arg(ap, char *);
		while (!isspace(*s) && *s != '\0') {
		    if (store_value) {
		        *charp = *s;
		        charp++;
		    }
		    s++;
		}
		
		if (store_value) {
		    *charp = '\0';
		    count++;
		}
	    } else if (*f == 'd') {
		if (*s == '\0') {
		    if (count == 0)
			return EOF;
		    else break;
		}
		if (*s < '0' || *s > '9')
		    break;
		if (store_value) {
		    intp = va_arg(ap, int *);
		    *intp = 0;
		}
		if (store_value)
		    *intp = atoi(s);
		while ('0' <= *s && *s <= '9') {
		    s++;
		}
		s--;
		if (store_value)
		    count++;
	    } else if (*f == '[') {
		if (*s == '\0') {
		    if (count == 0)
			return EOF;
		    else break;
		}
		bracket_chars = 0;
		f++;
		if (*f == '^') {
		    f++;
		    scanset_negated = TRUE;
		} else
		    scanset_negated = FALSE;
		if (*f == ']') {
		    f++;
		    bracket_chars = 1;
		}
		while (*f != ']' && *f != '\0') {
		    f++;
		    bracket_chars++;
		}
		if (*f != ']')
		    break;
		if (store_value)
		    charp = va_arg(ap, char *);
		if (scanset_negated) {
		    if (chr_in_mem(f - bracket_chars, *s, bracket_chars))
			break;
		    while (!chr_in_mem(f - bracket_chars, *s, bracket_chars)) {
			if (store_value) {
			    *charp = *s;
			    charp++;
			}
			s++;
			if (*s == '\0')
			    break;
		    }
		} else {
		    if (!chr_in_mem(f - bracket_chars, *s, bracket_chars))
			break;
		    while (chr_in_mem(f - bracket_chars, *s, bracket_chars)) {
			if (store_value) {
			    *charp = *s;
			    charp++;
			}
			s++;
			if (*s == '\0') // Should never happen but included anyway
			    break;
		    }
		}
		if (store_value) {
		    *charp = '\0';
		    count++;
		}
		s--;
	    } else if (*f == '0') {
		if (*s == '\0') {
		    if (count == 0)
			return EOF;
		    else break;
		}
		f++;
		field_width = 0;
		while ('0' <= *f && *f <= '9') {
		    field_width *= 10;
		    field_width += (*f - '0');
		    f++;
		}
		
		if (*f != 'x' && *f != 'X' && *f != 'l')
		    break;
		
		if (*f == 'l') {
		    if (*(f + 1) != 'x' && *(f + 1) != 'X')
			break;
		    if (store_value) {
			longp = va_arg(ap, unsigned long *);
			*longp = 0;
		    }
		    hex_use_long = TRUE;
		    f++;
		} else {
		    if (store_value) {
			intp = va_arg(ap, int *);
			*intp = 0;
		    }
		    hex_use_long = FALSE;
		}
		
		if (!('0' <= *s && *s <= '9') && !('a' <= *s && *s <= 'f')
		    && !('A' <= *s && *s <= 'F'))
		    break;
		
		for (loop = 0; loop < field_width; loop++) {
		    if (!('0' <= *s && *s <= '9') && !('a' <= *s && *s <= 'f')
			&& !('A' <= *s && *s <= 'F'))
			break;
		    
		    // Horner's Rule
		    if (hex_use_long) {
			if (store_value) {
			    *longp *= 16;
			    if ('0' <= *s && *s <= '9') {
				*longp += (*s - '0');
			    } else if ('a' <= *s && *s <= 'f') {
				*longp += (*s - 'a' + 10);
			    } else if ('A' <= *s && *s <= 'F') {
				*longp += (*s - 'A' + 10);
			    }
			}
		    } else {
			if (store_value) {
			    *intp *= 16;
			    if ('0' <= *s && *s <= '9') {
				*intp += (*s - '0');
			    } else if ('a' <= *s && *s <= 'f') {
				*intp += (*s - 'a' + 10);
			    } else if ('A' <= *s && *s <= 'F') {
				*intp += (*s - 'A' + 10);
			    }
			}
		    }
		    s++;
		}
		
		s--;
		if (store_value)
		    count++;
	    } else break;
	} else {
	    if (*s == '\0') {
		if (count == 0)
		    return EOF;
		else break;
	    }
	    if (*s != *f)
		break;
	}
	
	f++;
	s++;
    }
    va_end(ap);
    return count;
}
#endif