stmbl

//
//  scanf.c
//  test
//
//  Created by crinq on 05.12.13.
//  Copyright (c) 2013 Rene Hopf. All rights reserved.
//

#include <stdarg.h>
#include "scanf.h"



int vfscanf_(const char *format, va_list arg);

int scanf_(const char *format, ...){
    int ret = 0;

    va_list arg;
		va_start(arg, format);
    ret = vfscanf_(format, arg);
    va_end(arg);
    return(ret);
}



int isBinDigit(char c){
    return(c == '0' || c == '1');
}

int isChar(char c){
	return((c <= 'Z' && c >= 'A') || (c <= 'z' && c >= 'a') || isBinDigit(c));
}

int isDecDigit(char c){
    return(c >= '0' && c <= '9');
}

int isHexDigit(char c){
    return((c >= '0' && c <= '9') || (c >= 'A' && c <= 'F')  || (c >= 'a' && c <= 'f'));
}

int isWhitespace(char c){
    return(c == ' ' || c == '\t');
}

int vfscanf_(const char *format, va_list arg){
    int buffer_pos = 0;
    int format_pos = 0;
		int string_pos = 0;

    int *i;
    float *f;
    char *c;
    //char s[SCANF_ASIZE];
    int invert;
    float tf;

    int state = 0;  // 0 = last char = normal char
    // 1 = last char = '%'
    // 2 = last char = '\'

    while(format[format_pos]){
        switch(state){
            case 0:
                switch(format[format_pos]){
                    case '%':
                        state = 1;
                    break;

                    case '\'':
                        state = 2;
                    break;

										case ' ': // parse whithespaces
                    	while(isWhitespace(scanf_buffer[buffer_pos])){
												buffer_pos++;
                      }
                    break;

                    default:
                        if(format[format_pos] != scanf_buffer[buffer_pos++]){
                            return(format_pos);
                        }
                }
            break;

            case 1:
                switch(format[format_pos]){
                    case '%':
                        if(scanf_buffer[buffer_pos++] != '%'){
                            return(format_pos);
                        }
                    break;

                    case 'c':
                        c = va_arg(arg, char *);
                        *c = scanf_buffer[buffer_pos++];
                    break;

					case 's':
						string_pos = 0;
                        c = va_arg(arg, char *);
						while(isChar(scanf_buffer[buffer_pos])){
							c[string_pos] = scanf_buffer[buffer_pos++];
							string_pos++;
                      	}
                    break;

                    case 'i':
                        i = va_arg(arg, int *);
                        *i = 0;
                        invert = 1;
                        if(scanf_buffer[buffer_pos] == '-'){
                            invert = -1;
                            buffer_pos++;
                        }
                        else if(scanf_buffer[buffer_pos] == '+'){
                            buffer_pos++;
                        }
                        while(isDecDigit(scanf_buffer[buffer_pos])){
                            *i *= 10;
                            *i += scanf_buffer[buffer_pos++] - '0';
                        }
                        *i *= invert;
                    break;

                    case 'b':
                        i = va_arg(arg, int *);
                        *i = 0;
                        invert = 1;
                        if(scanf_buffer[buffer_pos] == '-'){
                            invert = -1;
                            buffer_pos++;
                        }
                        else if(scanf_buffer[buffer_pos] == '+'){
                            buffer_pos++;
                        }
                        if(!(scanf_buffer[buffer_pos] == 'b' || scanf_buffer[buffer_pos] == 'B')){
                            return(format_pos);
                        }
                        buffer_pos++;
                        while(isBinDigit(scanf_buffer[buffer_pos])){
                            *i *= 2;
                            *i += scanf_buffer[buffer_pos++] - '0';
                        }
                        *i *= invert;
                    break;

                    case 'h':
                        i = va_arg(arg, int *);
                        *i = 0;
                        invert = 1;
                        if(scanf_buffer[buffer_pos] == '-'){
                            invert = -1;
                            buffer_pos++;
                        }
                        else if(scanf_buffer[buffer_pos] == '+'){
                            buffer_pos++;
                        }
                        if(scanf_buffer[buffer_pos++] != '0'){
                            return(format_pos);
                        }
                        if(scanf_buffer[buffer_pos++] != 'x'){
                            return(format_pos);
                        }
                        while(isHexDigit(scanf_buffer[buffer_pos])){
                            *i *= 16;
                            if(scanf_buffer[buffer_pos] < 'A'){
                                *i += scanf_buffer[buffer_pos++] - '0';
                            }
                            else if(scanf_buffer[buffer_pos] < 'a'){
                                *i += scanf_buffer[buffer_pos++] - 'A' + 10;
                            }
                            else{
                                *i += scanf_buffer[buffer_pos++] - 'a' + 10;
                            }
                        }
                        *i *= invert;
                    break;

                    case 'f':
                        f = va_arg(arg, float *);
                        *f = 0;
												tf = 10;
                        invert = 1;
                        if(scanf_buffer[buffer_pos] == '-'){
                            invert = -1;
                            buffer_pos++;
                        }
                        else if(scanf_buffer[buffer_pos] == '+'){
                            buffer_pos++;
                        }
                        while(isDecDigit(scanf_buffer[buffer_pos])){
                            *f *= 10;
                            *f += scanf_buffer[buffer_pos++] - '0';
                        }
                        if(scanf_buffer[buffer_pos] == '.'){
                            buffer_pos++;
                            while(isDecDigit(scanf_buffer[buffer_pos])){
                                *f += (scanf_buffer[buffer_pos++] - '0') / tf;
																tf *= 10;
                            }
                        }
                        *f *= invert;
                    break;

                    default:
                        return(format_pos);
                    break;
                }
							state = 0;
            break;

            case 2:
                switch(format[format_pos]){
                    case '\'':
                        if(scanf_buffer[buffer_pos++] != '\''){
                            return(format_pos);
                        }
                    break;

                    case 'n':
                        if(scanf_buffer[buffer_pos++] != '\n'){
                            return(format_pos);
                        }
                    break;

                    default:
                        return(format_pos);
                    break;
                }
							state = 0;
            break;

            default:
            break;
        }

        format_pos++;
    }
    return(format_pos);
}