numbers.h

Go to the documentation of this file.

#ifndef LIBPROPELLER_NUMBERS_H_
#define LIBPROPELLER_NUMBERS_H_

#include <string.h>

class Numbers {
public:

    static char * Dec(int number, char result_string[] = NULL) {
        if (result_string == NULL) {
            result_string = internalBuffer;
        }
        //Source: http://www.cplusplus.com/articles/D9j2Nwbp/
        int i, sign;

        if ((sign = number) < 0) /* record sign */
            number = -number; /* make n positive */
        i = 0;
        do { /* generate digits in reverse order */
            result_string[i++] = number % 10 + '0'; /* get next digit */
        } while ((number /= 10) > 0); /* delete it */
        if (sign < 0)
            result_string[i++] = '-';
        result_string[i] = '\0';
        Reverse(result_string);

        return result_string;
    }

    static int Dec(const char * number, const char terminator = '\0') {
        int result = 0;
        int index = 0;
        bool isNegative = false;
        if (number[index] == '-') {
            isNegative = true;
            index++;
        }
        for (; number[index] != terminator; index++) {
            //       Shift left      Add 1's unit
            result = (result * 10) + (number[index] - '0');
        }

        if (isNegative) {
            return -result;
        } else {
            return result;
        }
    }

    static char * Hex(int number, const int num_digits, char result_string[] = NULL) {
        if (result_string == NULL) {
            result_string = internalBuffer;
        }
        static const char characters[] = "0123456789ABCDEF";
        int i;
        for (i = 0; i < num_digits; i++) {
            result_string[i] = characters[number & 0xF];
            number >>= 4;
        }
        result_string[i] = 0;
        Reverse(result_string);
        return result_string;
    }

    static char * Bin(int number, int num_digits, char result_string[] = NULL) {
        if (result_string == NULL) {
            result_string = internalBuffer;
        }
        // Below is C++ version:
        static const char characters[] = "01";
        int i;
        for (i = 0; i < num_digits; i++) {
            result_string[i] = characters[number & 0b1];
            number >>= 1;
        }
        result_string[i] = 0;
        Reverse(result_string);
        return result_string;

    }

    static int DecDigits(int number) {
        int sign = 0;
        if (number < 0) {
            number = -number;
            sign = 1;
        }
        if (number < 100000) {
            // 5 or less
            if (number < 100) {
                // 1 or 2
                if (number < 10)
                    return 1 + sign;
                else
                    return 2 + sign;
            } else {
                // 3 or 4 or 5
                if (number < 1000)
                    return 3 + sign;
                else {
                    // 4 or 5
                    if (number < 10000)
                        return 4 + sign;
                    else
                        return 5 + sign;
                }
            }
        } else {
            // 6 or more
            if (number < 10000000) {
                // 6 or 7
                if (number < 1000000)
                    return 6 + sign;
                else
                    return 7 + sign;
            } else {
                // 8 to 10
                if (number < 100000000)
                    return 8 + sign;
                else {
                    // 9 or 10
                    if (number < 1000000000)
                        return 9 + sign;
                    else
                        return 10 + sign;
                }
            }
        }
    }

    static int HexDigits(const int n) {
        if ((n & 0xFFFF) == n) {
            //4 or less
            if ((n & 0xFF) == n) {
                //2 or less
                if ((n & 0xF) == n)
                    return 1;
                else
                    return 2;
            } else
                //4 or 3
                if ((n & 0xFFF) == n)
                return 3;
            else
                return 4;

        } else {
            //5 or more
            if ((n & 0xFFFFFF) == n) {
                //6 or 5
                if ((n & 0xFFFFF) == n)
                    return 5;
                else
                    return 6;
            } else {
                if ((n & 0xFFFFFFF) == n)
                    return 7;
                else
                    return 8;
            }
        }
    }

    static char * Reverse(char s[]) {
        //Source: http://www.cplusplus.com/articles/D9j2Nwbp/
        int i, j;
        char c;

        for (i = 0, j = strlen(s) - 1; i < j; i++, j--) {
            c = s[i];
            s[i] = s[j];
            s[j] = c;
        }
        return s;
    }

private:

    static char internalBuffer[];
};

#endif // LIBPROPELLER_NUMBERS_H_