hashtables

src/include/Makefile

@@ -1,5 +1,5 @@
 objects := $(patsubst %.c,%.o,$(wildcard *.c))
-subdirs := stdio string
+subdirs := stdio string hashtable
 OBJPATH=$(OBJDIR)/include
 export
 

src/include/hashtable.h

@@ -0,0 +1,23 @@
+#ifndef _HASHTABLE_H_INCLUDE
+#define _HASHTABLE_H_INCLUDE
+
+#include <stddef.h>
+#include <stdbool.h>
+
+typedef struct{
+	void* next;
+	char* key;
+	void* val;
+} hashtableentry;
+
+typedef struct{
+	size_t size;
+	hashtableentry* entries;
+} hashtable;
+
+bool hashtable_init(hashtable*, size_t);
+bool hashtable_insert(hashtable*, char*, void*);
+bool hashtable_remove(hashtable*, char*);
+void* hashtable_get(hashtable*, char*);
+
+#endif

src/include/hashtable/Makefile

@@ -0,0 +1,11 @@
+objects := $(patsubst %.c,%.o,$(wildcard *.c))
+subdirs := 
+OBJPATH=$(OBJDIR)/include/hashtable/
+export
+
+all: $(subdirs) $(objects)
+
+%.o: %.c
+	$(CC) $(CFLAGS) -o $@ $<
+	mkdir -p $(OBJPATH) 
+	cp $@ $(OBJPATH)/$@

src/include/hashtable/hashtable.c

@@ -0,0 +1,114 @@
+#include <hashtable.h>
+#include <string.h>
+#include <kernel/alloc.h>
+
+// temporary for testing
+
+size_t hash(char* ptr, size_t size){
+	size_t hash = 0;
+	for(size_t i = 0; i < size; ++i){
+		hash += ptr[i] * 9;
+	}
+
+	return hash % 883;
+
+}
+
+bool hashtable_init(hashtable* table, size_t size){
+	table->entries = alloc(size*sizeof(hashtableentry));
+	if(!table->entries) return false;
+	table->size = size;
+	return true;
+}
+
+static inline hashtableentry* getentry(hashtable* table, char* key){
+	size_t entryn = hash(key, strlen(key)) % table->size;
+
+	return &table->entries[entryn];
+}
+
+bool hashtable_insert(hashtable* table, char* key, void* val){
+
+	
+	hashtableentry* entry = getentry(table, key);
+
+	char* keysave = alloc(strlen(key)+1);
+
+	memcpy(keysave, key, strlen(key)+1);
+
+	if(!keysave) return false;
+
+	if(entry->key){
+		while(entry->next)
+			entry = entry->next;
+
+		entry->next = alloc(sizeof(hashtableentry));
+
+		if(!entry->next){
+			free(keysave);
+			return false;
+		}
+
+		entry = entry->next;
+	}
+	
+	entry->key = keysave;
+	entry->val = val;
+	
+	return true;
+
+}
+
+bool hashtable_remove(hashtable* table, char* key){
+	
+	hashtableentry* entry = getentry(table, key);
+	
+	if(!entry->key) return false;
+	
+	hashtableentry* prev = NULL;
+	
+	while(entry){
+		if(!strcmp(entry->key, key))
+			break;
+		prev = entry;
+		entry = entry->next;
+	}
+	
+	if(!entry) return false;
+
+	if(prev){
+		prev->next = entry->next;
+		free(entry->key);
+		free(entry);
+	}
+	else{
+		if(entry->next){
+			void* addr = entry->next;
+			memcpy(entry, entry->next, sizeof(hashtableentry));
+			free(addr);
+		}
+		else{
+			memset(entry, 0, sizeof(hashtableentry));
+		}
+		return true;
+	}
+
+
+	return true;
+
+}
+
+void* hashtable_get(hashtable* table, char* key){
+	
+	hashtableentry* entry = getentry(table, key);
+	
+	if(!entry->key)
+		return NULL;
+
+	while(entry && strcmp(entry->key, key))
+		entry = entry->next;
+
+	if(!entry) return NULL;
+	
+	return entry->val;
+}