init commit

hashtable/Makefile

@@ -0,0 +1,21 @@
+CC=gcc
+CFLAGS=-Wall -Wextra
+
+OBJS=test.o hashtable.o llist.o
+
+all: test
+
+test: $(OBJS)
+	gcc -o $@ $^
+
+test.o: test.c http.h
+
+hashtable.o: hashtable.c hashtable.h
+
+llist.o: llist.c llist.h
+
+clean:
+	rm -f $(OBJS)
+	rm -f test
+
+.PHONY: all, clean

hashtable/hashtable.c

@@ -0,0 +1,153 @@
+/**
+ * hashtable.c - A basic hashtable implementation
+ * 
+ */
+
+#include <string.h>
+#include <stdlib.h>
+
+#include "llist.h"
+#include "hashtable.h"
+
+#define SIZE 128
+
+typedef struct
+{
+    void* key;
+    void* data;
+}
+HTEntry;
+
+/**
+ * Simple hash function used
+ */
+int hash(char* key, int ht_size)
+{
+    int h = 0;
+
+    // basic modulo hash
+    for (size_t i = 0; i < strlen(key); i++)
+    {
+        h = (31 * h + key[i]) % ht_size;
+    }    
+
+    return h;
+}
+
+/**
+ * Compare function for searching a bucket
+ */
+int compare(void* data, void* arg)
+{
+    char* key = arg;
+    HTEntry* entry = data;
+    return strcmp(entry->key, key);
+}
+
+/**
+ * Delete HT entry from bucket
+ */
+int delete_entry(void* data, void* arg)
+{
+    (void) arg;
+    HTEntry* entry = data;
+    free(entry);
+    return 0;
+}
+
+/**
+ * Create a new hashtable
+ */
+HT* ht_create(void)
+{
+    HT* ht = malloc(sizeof(HT));
+
+    ht->size = SIZE;
+    ht->entries = 0;
+    ht->store = malloc(ht->size * sizeof(LL*));
+
+    for (int i = 0; i < ht->size; i++)
+    {
+        ht->store[i] = ll_create();
+    }
+
+    return ht;
+}
+
+/**
+ * Add a new key value pair to a hashtable
+ */
+int ht_put(HT* ht, char* key, void* data)
+{
+    int addr = hash(key, ht->size);
+
+    LL* bucket = ht->store[addr];
+
+    HTEntry* entry = malloc(sizeof(HTEntry));
+    entry->key = strdup(key);
+    entry->data = data;
+
+    ll_push(bucket, entry);
+
+    ht->entries++;
+
+    return 0;
+}
+
+/**
+ * Get a value from a hashtable with a key
+ */
+void* ht_get(HT* ht, char* key)
+{
+    int addr = hash(key, ht->size);
+
+    LL* bucket = ht->store[addr];
+
+    HTEntry* entry = ll_search(bucket, compare, (void*) key);
+
+    if (entry == NULL)
+    {
+        return NULL;
+    }
+
+    return entry->data;
+}
+
+/**
+ * Delete a key value pair from a hashtable
+ */
+void* ht_delete(HT* ht, char* key)
+{
+    int addr = hash(key, ht->size);
+
+    LL* bucket = ht->store[addr];
+
+    HTEntry* entry = ll_delete(bucket, compare, key);
+
+    if (entry == NULL)
+    {
+        return NULL;
+    }
+
+    ht->entries--;
+
+    return entry->data;
+}
+
+
+/**
+ * Destroy/free an entire hashtable
+ */
+int ht_free(HT* ht)
+{
+    for (int i = 0; i < ht->size; i++)
+    {
+        LL* bucket = ht->store[i];
+        ll_loop(bucket, delete_entry, NULL);
+        ll_free(bucket);
+    }
+
+    free(ht);
+
+    return 0;
+}

hashtable/hashtable.h

@@ -0,0 +1,24 @@
+#ifndef _HASHTABLE_H_
+#define _HASHTABLE_H_
+
+#include "llist.h"
+
+typedef struct
+{
+    int size;
+    int entries;
+    LL** store;
+}
+HT;
+
+HT* ht_create(void);
+
+int ht_put(HT* ht, char* key, void* data);
+
+void* ht_get(HT* ht, char* key);
+
+void* ht_delete(HT* ht, char* key);
+
+int ht_free(HT* ht);
+
+#endif

hashtable/test.c

@@ -0,0 +1,34 @@
+#include <stdio.h>
+#include <assert.h>
+
+#include "hashtable.h"
+
+int main(void)
+{
+    puts("Creating new hashtable...");
+
+    HT* ht = ht_create();
+
+    char* login_data = "This is the login data!";
+    char* register_data = "This is the register data!";
+
+    puts("Putting in some data...");
+
+    ht_put(ht, "/login", login_data);
+    ht_put(ht, "/register", register_data);
+
+    puts("Getting values and asserting they are correct...");
+
+    assert(login_data == ht_get(ht, "/login"));
+    assert(register_data == ht_get(ht, "/register"));
+
+    puts("Checking that delete works...");
+
+    ht_delete(ht, "/login");
+
+    assert(ht_get(ht, "/login") == NULL);
+
+    puts("Tests complete!");
+
+    return 0;
+}