diff --git a/Others/BestFit.java b/Others/BestFit.java new file mode 100644 index 000000000..71814d22b --- /dev/null +++ b/Others/BestFit.java @@ -0,0 +1,89 @@ +package Others; + +import java.util.ArrayList; + +/** + * @author Dekas Dimitrios + */ +public class BestFit { + private static final int NO_ALLOCATION = -255; // if a process has been allocated in position -255, + // it means that it has not been actually allocated. + + /** + * Method to find the maximum valued element of an array filled with positive integers. + * + * @param array: an array filled with positive integers. + * @return the maximum valued element of the array. + */ + private static int findMaxElement(int[] array) { + int max = -1; + for (int value : array) { + if (value > max) { + max = value; + } + } + return max; + } + + /** + * Method to find the index of the memory block that is going to fit the given process based on the best fit algorithm. + * + * @param blocks: the array with the available memory blocks. + * @param process: the size of the process. + * @return the index of the block that fits, or -255 if no such block exists. + */ + private static int findBestFit(int[] blockSizes, int processSize) { + // Initialize minDiff with an unreachable value by a difference between a blockSize and the processSize. + int minDiff = findMaxElement(blockSizes); + int index = NO_ALLOCATION; // If there is no block that can fit the process, return NO_ALLOCATION as the result. + for(int i=0 ; i < blockSizes.length ; i++) { // Find the most fitting memory block for the given process. + if(blockSizes[i] - processSize < minDiff && blockSizes[i] - processSize >= 0) { + minDiff = blockSizes[i] - processSize; + index = i; + } + } + return index; + } + + /** + * Method to allocate memory to blocks according to the best fit + * algorithm. It should return an ArrayList of Integers, where the + * index is the process ID (zero-indexed) and the value is the block + * number (also zero-indexed). + * + * @param sizeOfBlocks: an int array that contains the sizes of the memory blocks available. + * @param sizeOfProcesses: an int array that contains the sizes of the processes we need memory blocks for. + * @return the ArrayList filled with Integers repressenting the memory allocation that took place. + */ + static ArrayList bestFit(int[] sizeOfBlocks, int[] sizeOfProcesses) { + // The array list responsible for saving the memory allocations done by the best-fit algorithm + ArrayList memAlloc = new ArrayList<>(); + // Do this for every process + for(int processSize : sizeOfProcesses) { + int chosenBlockIdx = findBestFit(sizeOfBlocks, processSize); // Find the index of the memory block going to be used + memAlloc.add(chosenBlockIdx); // Store the chosen block index in the memAlloc array list + if(chosenBlockIdx != NO_ALLOCATION) { // Only if a block was chosen to store the process in it, + sizeOfBlocks[chosenBlockIdx] -= processSize; // resize the block based on the process size + } + } + return memAlloc; + } + + /** + * Method to print the memory allocated. + * + * @param memAllocation: an ArrayList of Integer representing the memory allocation done by the bestFit method. + */ + public static void printMemoryAllocation(ArrayList memAllocation) { + System.out.println("Process No.\tBlock No."); + System.out.println("===========\t========="); + for (int i = 0; i < memAllocation.size(); i++) { + System.out.print(" " + i + "\t\t"); + if (memAllocation.get(i) != NO_ALLOCATION) + System.out.print(memAllocation.get(i)); + else + System.out.print("Not Allocated"); + System.out.println(); + } + } +} \ No newline at end of file diff --git a/Others/FirstFit.java b/Others/FirstFit.java new file mode 100644 index 000000000..61a25b422 --- /dev/null +++ b/Others/FirstFit.java @@ -0,0 +1,70 @@ +package Others; + +import java.util.ArrayList; + +/** + * @author Dekas Dimitrios + */ +public class FirstFit { + private static final int NO_ALLOCATION = -255; // if a process has been allocated in position -255, + // it means that it has not been actually allocated. + + /** + * Method to find the index of the memory block that is going to fit the given process based on the first fit algorithm. + * + * @param blocks: the array with the available memory blocks. + * @param process: the size of the process. + * @return the index of the block that fits, or -255 if no such block exists. + */ + private static int findFirstFit(int[] blockSizes, int processSize) { + for(int i=0 ; i < blockSizes.length ; i++) { + if(blockSizes[i] >= processSize) { + return i; + } + } + // If there is not a block that can fit the process, return -255 as the result + return NO_ALLOCATION; + } + + /** + * Method to allocate memory to blocks according to the first fit + * algorithm. It should return an ArrayList of Integers, where the + * index is the process ID (zero-indexed) and the value is the block + * number (also zero-indexed). + * + * @param sizeOfBlocks: an int array that contains the sizes of the memory blocks available. + * @param sizeOfProcesses: an int array that contains the sizes of the processes we need memory blocks for. + * @return the ArrayList filled with Integers repressenting the memory allocation that took place. + */ + static ArrayList firstFit(int[] sizeOfBlocks, int[] sizeOfProcesses) { + // The array list responsible for saving the memory allocations done by the first-fit algorithm + ArrayList memAlloc = new ArrayList<>(); + // Do this for every process + for(int processSize : sizeOfProcesses) { + int chosenBlockIdx = findFirstFit(sizeOfBlocks, processSize); // Find the index of the memory block going to be used + memAlloc.add(chosenBlockIdx); // Store the chosen block index in the memAlloc array list + if(chosenBlockIdx != NO_ALLOCATION) { // Only if a block was chosen to store the process in it, + sizeOfBlocks[chosenBlockIdx] -= processSize; // resize the block based on the process size + } + } + return memAlloc; + } + + /** + * Method to print the memory allocated. + * + * @param memAllocation: an ArrayList of Integer representing the memory allocation done by the firstFit method. + */ + public static void printMemoryAllocation(ArrayList memAllocation) { + System.out.println("Process No.\tBlock No."); + System.out.println("===========\t========="); + for (int i = 0; i < memAllocation.size(); i++) { + System.out.print(" " + i + "\t\t"); + if (memAllocation.get(i) != NO_ALLOCATION) + System.out.print(memAllocation.get(i)); + else + System.out.print("Not Allocated"); + System.out.println(); + } + } +} \ No newline at end of file diff --git a/Others/WorstFit.java b/Others/WorstFit.java new file mode 100644 index 000000000..0bb6c460b --- /dev/null +++ b/Others/WorstFit.java @@ -0,0 +1,76 @@ +package Others; + +import java.util.ArrayList; + +/** + * @author Dekas Dimitrios + */ +public class WorstFit { + private static final int NO_ALLOCATION = -255; // if a process has been allocated in position -255, + // it means that it has not been actually allocated. + + /** + * Method to find the index of the memory block that is going to fit the given process based on the worst fit algorithm. + * + * @param blocks: the array with the available memory blocks. + * @param process: the size of the process. + * @return the index of the block that fits, or -255 if no such block exists. + */ + private static int findWorstFit(int[] blockSizes, int processSize) { + int max = -1; + int index = -1; + for(int i=0 ; i < blockSizes.length ; i++) { // Find the index of the biggest memory block available. + if(blockSizes[i] > max) { + max = blockSizes[i]; + index = i; + } + } + // If the biggest memory block cannot fit the process, return -255 as the result + if(processSize > blockSizes[index]) { + return NO_ALLOCATION; + } + return index; + } + + /** + * Method to allocate memory to blocks according to the worst fit + * algorithm. It should return an ArrayList of Integers, where the + * index is the process ID (zero-indexed) and the value is the block + * number (also zero-indexed). + * + * @param sizeOfBlocks: an int array that contains the sizes of the memory blocks available. + * @param sizeOfProcesses: an int array that contains the sizes of the processes we need memory blocks for. + * @return the ArrayList filled with Integers repressenting the memory allocation that took place. + */ + static ArrayList worstFit(int[] sizeOfBlocks, int[] sizeOfProcesses) { + // The array list responsible for saving the memory allocations done by the worst-fit algorithm + ArrayList memAlloc = new ArrayList<>(); + // Do this for every process + for(int processSize : sizeOfProcesses) { + int chosenBlockIdx = findWorstFit(sizeOfBlocks, processSize); // Find the index of the memory block going to be used + memAlloc.add(chosenBlockIdx); // Store the chosen block index in the memAlloc array list + if(chosenBlockIdx != NO_ALLOCATION) { // Only if a block was chosen to store the process in it, + sizeOfBlocks[chosenBlockIdx] -= processSize; // resize the block based on the process size + } + } + return memAlloc; + } + + /** + * Method to print the memory allocated. + * + * @param memAllocation: an ArrayList of Integer representing the memory allocation done by the worstFit method. + */ + public static void printMemoryAllocation(ArrayList memAllocation) { + System.out.println("Process No.\tBlock No."); + System.out.println("===========\t========="); + for (int i = 0; i < memAllocation.size(); i++) { + System.out.print(" " + i + "\t\t"); + if (memAllocation.get(i) != NO_ALLOCATION) + System.out.print(memAllocation.get(i)); + else + System.out.print("Not Allocated"); + System.out.println(); + } + } +} \ No newline at end of file