1 files changed, 140 insertions, 0 deletions
diff --git a/P2/src/reducer.c b/P2/src/reducer.c
new file mode 100644
index 0000000..d62c2c2
--- /dev/null
+++ b/P2/src/reducer.c
@@ -0,0 +1,140 @@
+#include "reducer.h"
+
+finalKeyValueDS *createFinalKeyValueNode(char *word, int count){
+	finalKeyValueDS *newNode = (finalKeyValueDS *)malloc (sizeof(finalKeyValueDS));
+	strcpy(newNode -> key, word);
+	newNode -> value = count;
+	newNode -> next = NULL;
+	return newNode;
+}
+
+finalKeyValueDS *insertNewKeyValue(finalKeyValueDS *root, char *word, int count){
+	finalKeyValueDS *tempNode = root;
+	if(root == NULL)
+		return createFinalKeyValueNode(word, count);
+	while(tempNode -> next != NULL){
+		if(strcmp(tempNode -> key, word) == 0){
+			tempNode -> value += count;
+			return root;
+		}
+		tempNode = tempNode -> next;
+	}
+	if(strcmp(tempNode -> key, word) == 0){
+		tempNode -> value += count;
+	} else{
+		tempNode -> next = createFinalKeyValueNode(word, count);
+	}
+	return root;
+}
+
+void freeFinalDS(finalKeyValueDS *root) {
+	if(root == NULL) return;
+
+	finalKeyValueDS *tempNode = NULL;
+	while (root != NULL){
+		tempNode = root;
+		root = root -> next;
+		free(tempNode);
+	}
+}
+
+// reduce function
+void reduce(char *key) {
+
+	char* wordFileName = key;
+	int fd = open(wordFileName, O_RDONLY);
+	if (fd < 0){
+		printf("ERROR: Cannot open the file %s\n", wordFileName);
+		exit(0);
+	}
+
+	char buffer[MAXKEYSZ];
+	char word[MAXKEYSZ];
+	memset(word, '\0', sizeof(char) * MAXKEYSZ);
+	int j = 0;
+	int foundKey = 0;
+	while(read(fd, &buffer[j], 1) == 1) {
+		// read one word at a time
+		if (buffer[j] == ' ' ||buffer[j] == '\n' || buffer[j] == 0x0) {
+			buffer[j] = '\0';
+
+			// just a safety code to avoid empty files or blank lines
+			if(strlen(buffer) == 0){
+				j = 0;
+				continue;
+			}
+
+			int count;
+			if(!foundKey){
+				// found the word
+				foundKey = 1;
+				strcpy(word, buffer);
+				count = 0;
+			} else {
+				// convert string count to integer count
+				count = strtol(buffer, NULL, 10);
+			}
+			finalDS = insertNewKeyValue(finalDS, word, count);
+			j = 0;
+			continue;
+		}
+		j++;
+	}
+	close(fd);
+}
+
+void writeFinalDS(int reducerID){
+	char reduceFileName[MAXKEYSZ];
+	memset(reduceFileName, '\0', MAXKEYSZ);
+	sprintf(reduceFileName, "output/ReduceOut/Reduce_%d.txt", reducerID);
+
+	int fdReduce = open(reduceFileName, O_CREAT | O_WRONLY, 0777);
+	if (fdReduce < 0){
+		printf("ERROR: Cannot open the file %s\n", reduceFileName);
+		exit(0);
+	}
+
+	finalKeyValueDS *tempNode = finalDS;
+	while(tempNode){
+		char writeKeyValue[2 * MAXKEYSZ];
+		memset(writeKeyValue, '\0', 2 * MAXKEYSZ);
+		strcpy(writeKeyValue, tempNode -> key);
+		strcat(writeKeyValue, " ");
+		char valueStr[MAXKEYSZ];
+		memset(valueStr, '\0', MAXKEYSZ);
+		sprintf(valueStr, "%d", tempNode -> value);
+		strcat(writeKeyValue, valueStr);
+		writeKeyValue[strlen(writeKeyValue)] = '\n';
+
+		// word write
+		int ret = write(fdReduce, writeKeyValue, strlen(writeKeyValue));
+		if(ret < 0){
+			printf("ERROR: Cannot write to file %s\n", reduceFileName);
+			exit(0);
+		}
+		tempNode = tempNode -> next;
+	}
+	close(fdReduce);
+}
+
+int main(int argc, char *argv[]) {
+
+	if(argc < 2){
+		printf("Less number of arguments.\n");
+		printf("./reducer reducerID");
+	}
+
+	// initialize 
+	int reducerID = strtol(argv[1], NULL, 10);
+	finalDS = NULL;
+
+	// master will continuously send the word.txt files alloted to the reducer
+	char key[MAXKEYSZ];
+	while(getInterData(key, reducerID))
+		reduce(key);
+
+	writeFinalDS(reducerID);
+
+	freeFinalDS(finalDS);
+	return 0;
+}
+\ No newline at end of file