Implemented and tested literal dictionary

source/literal_dictionary.c

@@ -0,0 +1,201 @@
+#include "literal_dictionary.h"
+
+#include "memory.h"
+
+#include <stdio.h>
+
+//util functions
+static void setEntryValues(_entry* entry, Literal key, Literal value) {
+	//free the original string and overwrite it
+	if (IS_STRING(entry->key)) {
+		freeLiteral(entry->key);
+	}
+
+	//take ownership of the copied string
+	if (IS_STRING(key)) {
+		char* buffer = ALLOCATE(char, STRLEN(key) + 1);
+		strncpy(buffer, AS_STRING(key), STRLEN(key));
+		buffer[STRLEN(key)] = '\0';
+		entry->key = TO_STRING_LITERAL(buffer); //buffer becomes a part of the key literal
+	}
+	
+	else {
+		entry->key = key;
+	}
+
+	//values
+	freeLiteral(entry->value);
+
+	//take ownership of the copied string
+	if (IS_STRING(value)) {
+		char* buffer = ALLOCATE(char, STRLEN(value) + 1);
+		strncpy(buffer, AS_STRING(value), STRLEN(value));
+		buffer[STRLEN(value)] = '\0';
+		entry->value = TO_STRING_LITERAL(buffer);
+	}
+	
+	else {
+		entry->value = value;
+	}
+}
+
+static _entry* getEntryArray(_entry* array, int capacity, Literal key, unsigned int hash, bool mustExist) {
+	//find "key", starting at index
+	unsigned int index = hash % capacity;
+	unsigned int start = index;
+
+	//increment once, so it can't equal start
+	index = (index + 1) % capacity;
+
+	//literal probing and collision checking
+	while (index != start) { //WARNING: this is the only function allowed to retrieve an entry from the array
+		_entry* entry = &array[index];
+
+		if (IS_NULL(entry->key)) { //if key is empty, it's either empty or tombstone
+			if (IS_NULL(entry->value) && !mustExist) {
+				//found a truly empty bucket
+				return entry;
+			}
+			//else it's a tombstone - ignore
+		} else {
+			if (literalsAreEqual(key, entry->key)) {
+				return entry;
+			}
+		}
+
+		index = (index + 1) % capacity;
+	}
+
+	return NULL;
+}
+
+static void adjustEntryCapacity(_entry** dictionaryHandle, int oldCapacity, int capacity) {
+	//new entry space
+	_entry* newEntries = ALLOCATE(_entry, capacity);
+
+	for (int i = 0; i < capacity; i++) {
+		newEntries[i].key = TO_NULL_LITERAL;
+		newEntries[i].value = TO_NULL_LITERAL;
+	}
+
+	//move the old array into the new one
+	for (int i = 0; i < oldCapacity; i++) {
+		if (IS_NULL((*dictionaryHandle)[i].key)) {
+			continue;
+		}
+
+		//place the key and value in the new array (reusing string memory)
+		_entry* entry = getEntryArray(newEntries, capacity, TO_NULL_LITERAL, hashLiteral((*dictionaryHandle)[i].key), false);
+
+		entry->key = (*dictionaryHandle)[i].key;
+		entry->value = (*dictionaryHandle)[i].value;
+	}
+
+	//clear the old array
+	FREE_ARRAY(_entry, *dictionaryHandle, oldCapacity);
+
+	*dictionaryHandle = newEntries;
+}
+
+static bool setEntryArray(_entry** dictionaryHandle, int* capacityPtr, int count, Literal key, Literal value, int hash) {
+	//expand array if needed
+	if (count + 1 > *capacityPtr * DICTIONARY_MAX_LOAD) {
+		int oldCapacity = *capacityPtr;
+		*capacityPtr = GROW_CAPACITY(*capacityPtr);
+		adjustEntryCapacity(dictionaryHandle, oldCapacity, *capacityPtr); //custom rather than automatic reallocation
+	}
+
+	_entry* entry = getEntryArray(*dictionaryHandle, *capacityPtr, key, hash, false);
+
+	//true = count increase
+	if (IS_NULL(entry->key)) {
+		setEntryValues(entry, key, value);
+		return true;
+	}
+	else {
+		setEntryValues(entry, key, value);
+		return false;
+	}
+
+	return false;
+}
+
+static void freeEntry(_entry* entry) {
+	freeLiteral(entry->key);
+	freeLiteral(entry->value);
+	entry->key = TO_NULL_LITERAL;
+	entry->value = TO_NULL_LITERAL;
+}
+
+static void freeEntryArray(_entry* array, int capacity) {
+	if (array == NULL) {
+		return;
+	}
+
+	for (int i = 0; i < capacity; i++) {
+		if (!IS_NULL(array[i].key)) {
+			freeEntry(&array[i]);
+		}
+	}
+
+	FREE_ARRAY(_entry, array, capacity);
+}
+
+//exposed functions
+void initLiteralDictionary(LiteralDictionary* dictionary) {
+	//HACK: because modulo by 0 is undefined, set the capacity to a non-zero value (and allocate the arrays)
+	dictionary->entries = NULL;
+	dictionary->capacity = GROW_CAPACITY(0);
+	dictionary->count = 0;
+	adjustEntryCapacity(&dictionary->entries, 0, dictionary->capacity);
+}
+
+void freeLiteralDictionary(LiteralDictionary* dictionary) {
+	freeEntryArray(dictionary->entries, dictionary->capacity);
+	dictionary->capacity = 0;
+	dictionary->count = 0;
+}
+
+void setLiteralDictionary(LiteralDictionary* dictionary, Literal key, Literal value) {
+	if (IS_NULL(key)) {
+		fprintf(stderr, "[Internal] Dictionaries can't have null keys\n");
+		return;
+	}
+
+	const int increment = setEntryArray(&dictionary->entries, &dictionary->capacity, dictionary->count, key, value, hashLiteral(key));
+
+	if (increment) {
+		dictionary->count++;
+	}
+}
+
+Literal getLiteralDictionary(LiteralDictionary* dictionary, Literal key) {
+	if (IS_NULL(key)) {
+		fprintf(stderr, "[Internal] Dictionaries can't have null keys\n");
+		return TO_NULL_LITERAL;
+	}
+
+	_entry* entry = getEntryArray(dictionary->entries, dictionary->capacity, key, hashLiteral(key), true);
+
+	if (entry != NULL) {
+		return entry->value;
+	}
+	else {
+		return TO_NULL_LITERAL;
+	}
+}
+
+void removeLiteralDictionary(LiteralDictionary* dictionary, Literal key) {
+	if (IS_NULL(key)) {
+		fprintf(stderr, "[Internal] Dictionaries can't have null keys\n");
+		return;
+	}
+
+	_entry* entry = getEntryArray(dictionary->entries, dictionary->capacity, key, hashLiteral(key), true);
+
+	if (entry != NULL) {
+		freeEntry(entry);
+		entry->value = TO_BOOLEAN_LITERAL(true); //tombstone
+	}
+}
+