#include <stdlib.h>

#include <string.h>

#include "types.h"

void

array_init(struct array *array)

{

	memset(array, 0, sizeof *array);

}

void

array_release(struct array *array)

{

	free(array->data);

}

void *

array_add(struct array *array, int size)

{

	int alloc;

	void *data, *p;

	if (array->alloc > 0)

		alloc = array->alloc;

	else

		alloc = 16;

	while (alloc < array->size + size)

		alloc *= 2;

	if (array->alloc < alloc) {

		data = realloc(array->data, alloc);

		if (data == NULL)

			return 0;

		array->data = data;

		array->alloc = alloc;

	}

	p = array->data + array->size;

	array->size += size;

	return p;

}

void

hashtable_init(struct hashtable *table, struct array *pool)

{

	array_init(&table->buckets);

	table->pool = pool;

}

void

hashtable_release(struct hashtable *table)

{

	array_release(&table->buckets);

}

static unsigned int

hash_string(const char *key)

{

	const char *p;

	unsigned int hash = 0;

	for (p = key; *p; p++)

		hash = (hash * 617) ^ *p;

	return hash;

}

uint32_t

hashtable_lookup(struct hashtable *table, const char *key)

{

	unsigned int mask, start, i;

	uint32_t *b;

	char *pool;

	pool = table->pool->data;

	mask = table->buckets.alloc - 1;

	start = hash_string(key) * sizeof(uint32_t);

	for (i = 0; i < table->buckets.alloc; i += sizeof *b) {

		b = table->buckets.data + ((start + i) & mask);

		if (*b == 0)

			return 0;

		if (strcmp(key, &pool[*b]) == 0)

			return *b;

	}

	return 0;

}

static void

do_insert(struct hashtable *table, uint32_t value)

{

	unsigned int mask, start, i;

	uint32_t *b;

	const char *key;

	key = (char *) table->pool->data + value;

	mask = table->buckets.alloc - 1;

	start = hash_string(key) * sizeof(uint32_t);

	for (i = 0; i < table->buckets.alloc; i += sizeof *b) {

		b = table->buckets.data + ((start + i) & mask);

		if (*b == 0) {

			*b = value;

			break;

		}

	}

}

static uint32_t

add_to_string_pool(struct hashtable *table, const char *key)

{

	int len;

	char *p;

	len = strlen(key) + 1;

	p = array_add(table->pool, len);

	memcpy(p, key, len);

	return p - (char *) table->pool->data;

}

uint32_t

hashtable_insert(struct hashtable *table, const char *key)

{

	uint32_t value, *buckets, *b, *end;

	int alloc;

	alloc = table->buckets.alloc;

	array_add(&table->buckets, 4 * sizeof *buckets);

	if (alloc != table->buckets.alloc) {

		end = table->buckets.data + alloc;

		memset(end, 0, table->buckets.alloc - alloc);

		for (b = table->buckets.data; b < end; b++) {

			value = *b;

			if (value != 0) {

				*b = 0;

				do_insert(table, value);

			}

		}

	}

	value = add_to_string_pool(table, key);

	do_insert (table, value);

	return value;

}

uint32_t

hashtable_tokenize(struct hashtable *table, const char *string)

{

	uint32_t token;

	if (string == NULL)

		string = "";

	token = hashtable_lookup(table, string);

	if (token != 0)

		return token;

	return hashtable_insert(table, string);

}