CS249-Projects/PA09-1108/GeneralUtility.c

// header file
#include "GeneralUtility.h"

// constants

/* Data Structures

typedef enum { NO_RESULT = -1, INITIALIZE_RAND_GENERATOR = 101,
                       GET_RANDOM_VALUE, CLEAR_RAND_GENERATOR } RandControlCode;

typedef enum { LOW_RAND_LIMIT = 10, HIGH_RAND_LIMIT = 99 } RandLimits;

Data Structures */

// function implementations

/*
Name: privateCompareStrings
Process: compares two strings as follows:
         - if left string is alphabetically greater than the right string,
         returns value greater than zero
         - if left string is alphabetically less than the right string,
         returns value less than zero
         - if strings are alphabetically equal but one is longer,
           longer one is greater
         - otherwise, returns zero
Function input/parameters: two strings to be compared (const char *)
Function output/parameters: none
Function output/returned: result as specified above (int)
Device input/ ---: none
Device output/ ---: none
Dependencies: privateGetStringLen
*/
int privateCompareStrings(const char *leftStr, const char *rightStr)
{
    int diff, index = 0;
    int leftStrLen = privateGetStringLen(leftStr);
    int rightStrLen = privateGetStringLen(rightStr);

    while (index < leftStrLen && index < rightStrLen)
    {
        diff = leftStr[index] - rightStr[index];
        if (diff != 0)
        {
            return diff;
        }
        index = index + 1;
    }
    return leftStrLen - rightStrLen;
}

/*
Name: privateCopyString
Process: copies string character for character up to NULL_CHAR of source string
Function input/parameters: source string to be copied (const char *)
Function output/parameters: destination string (char *)
Function output/returned: none
Device input/---: none
Device output/---: none
Dependencies: none
*/
void privateCopyString(char *dest, const char *source)
{
    int characterCount = 0;
    // use a while loop, check for !NULL_CHAR
    while (source[characterCount] != NULL_CHAR)
    {
        // copy the character accessed into dest string
        dest[characterCount] = source[characterCount];
        // iterate the number of characters
        characterCount = characterCount + 1;
    }
    // add a NULL_CHAR once done, characterCount is in the right place for \0
    dest[characterCount] = NULL_CHAR;
    // no return, void.
}

/*
Name: privateGenUniqueRandom
Process: generates a unique random value for a given set of data
         during a program,
         for control code:
         INITIALIZE_RAND_GENERATOR - initializes lookup array for use
         GET_RANDOM_VALUE - creates, tests, and returns random value
         CLEAR_RAND_GENERATOR - deallocates lookup array
Method input/parameters: HeapType item (const HeapType),
                         control code (RandControlCode)
Method output/parameters: none
Method output/returned: unique random value (int)
Device input/---: none
Device output/---: none
Dependencies: srand, privateGetRandBetween, privateIsInArray, malloc, free
Notes: protects from:
       accidental reinitialization,
       acquiring value without initialization,
       or deallocation without initialization
*/
int privateGenUniqueRandom(int heapCapacity, RandControlCode ctrlCode)
{
    // define the static array and size
    static int *randArray = NULL;
    static int size = 0;
    // check which ctrlCode is used
    if(ctrlCode == INITIALIZE_RAND_GENERATOR)
    {
        // if initializing
        // create the array with the capacity given
        randArray = (int *)malloc(sizeof(int) * heapCapacity);
        // set random seed
        srand(time(NULL));
        // set size to zero(just to be safe)
        size = 0;
    }
    else if(ctrlCode == GET_RANDOM_VALUE)
    {
        // if requesting for rand
        // generate random value, 
                            // makes sure the value currently isn't in the array
        int currentRand = privateGetRandBetween(LOW_RAND_LIMIT, HIGH_RAND_LIMIT);
        while (privateIsInArray(randArray, size, currentRand))
        {
            // generate new random.
            currentRand = privateGetRandBetween(LOW_RAND_LIMIT, HIGH_RAND_LIMIT);
        }
        // once found a number that isn't in array, put into array.
        randArray[size] = currentRand;
        // increment size
        size = size + 1;
        return currentRand;
    }
    // check to see if the array is actually initialized
    if(size != 0 && randArray != NULL)
    {
        // otherwise, clearing and freeing things if initialized.
        free(randArray);
    }
    return NO_RESULT;
}

/*
Name: privateGetRandBetween
Process: generates a random value between two limits, inclusive
Method input/parameters: lower and upper limits (int)
Method output/parameters: none
Method output/returned: random value generated as specified (int)
Device input/---: none
Device output/---: none
Dependencies: rand
*/
int privateGetRandBetween(int lowLimit, int highLimit)
{
    // return random number that was previously seeded
    return ((rand() % (highLimit - lowLimit + 1)) + lowLimit);
}

/*
Name: privateGetStringLen
Process: finds length of string
Function input/parameters: c-style string (const char *)
Function output/parameters: none
Function output/returned: calculated length of string (int)
Device input/ ---: none
Device output/ ---: none
Dependencies: none
*/
int privateGetStringLen(const char *str)
{
    int strLen = 0;
    // while through string until hit null.
    while (str[strLen] != NULL_CHAR)
    {
        // increment the length string iterator
        strLen = strLen + 1;
    }
    // return strLen
    return strLen;
}

/*
Name: privateIsInArray
Process: provided integer array, its size, and a test value,
         returns true if test value is in the array, false otherwise
Method input/parameters: integer array (int *),
                         test value (int)
Method output/parameters: none
Method output/returned: Boolean result of operation (bool)
Device input/---: none
Device output/---: none
Dependencies: none
*/
bool privateIsInArray(const int *array, int size, int testVal)
{
    int arrayIterator;
    // for loop through the array.
    for(arrayIterator = 0; arrayIterator < size; arrayIterator++)
    {
        // check to see if the testVal is at the location.
        if(array[arrayIterator] == testVal)
        {
            // if there, return true
            return true;
        }
    }
    // otherwise, return false since not found
    return false;
}