/*

 * Copyright (C) 2008  Kristian Høgsberg <krh@redhat.com>

 * Copyright (C) 2008  Red Hat, Inc

 *

 * This program is free software; you can redistribute it and/or modify

 * it under the terms of the GNU General Public License as published by

 * the Free Software Foundation; either version 2 of the License, or

 * (at your option) any later version.

 *

 * This program is distributed in the hope that it will be useful,

 * but WITHOUT ANY WARRANTY; without even the implied warranty of

 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the

 * GNU General Public License for more details.

 *

 * You should have received a copy of the GNU General Public License along

 * with this program; if not, write to the Free Software Foundation, Inc.,

 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.

 */

#include <stdlib.h>

#include <string.h>

#include "razor-internal.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;

}

/* RAZOR_IMMEDIATE and RAZOR_ENTRY_LAST must have the same value */

#define RAZOR_ENTRY_LAST 0x80

#define RAZOR_IMMEDIATE  0x80

#define RAZOR_EMPTY_LIST 0xff

void

list_set_empty(struct list_head *head)

{

	head->list_ptr = ~0;

	head->flags = RAZOR_EMPTY_LIST;

}

void

list_set_ptr(struct list_head *head, uint32_t ptr)

{

	head->list_ptr = ptr;

	head->flags = 0;

}

void

list_set_array(struct list_head *head, struct array *pool,

	       struct array *items, int force_indirect)

{

	struct list *p;

	if (!force_indirect) {

		if (items->size == 0) {

			list_set_empty(head);

			return;

		} else if (items->size == sizeof (uint32_t)) {

			head->list_ptr = *(uint32_t *) items->data;

			head->flags = RAZOR_IMMEDIATE;

			return;

		}

	}

	p = array_add(pool, items->size);

	memcpy(p, items->data, items->size);

	p[items->size / sizeof *p - 1].flags = RAZOR_ENTRY_LAST;

	list_set_ptr(head, p - (struct list *) pool->data);

}

struct list *

list_first(struct list_head *head, struct array *pool)

{

	if (head->flags == RAZOR_EMPTY_LIST)

		return NULL;

	else if (head->flags == RAZOR_IMMEDIATE)

		return (struct list *) head;

	else

		return (struct list *) pool->data + head->list_ptr;

}

struct list *

list_next(struct list *list)

{

	if (list->flags)

		return NULL;

	return ++list;

}

void

list_remap_pool(struct array *pool, uint32_t *map)

{

	struct list *p, *end;

	end = pool->data + pool->size;

	for (p = pool->data; p < end; p++)

		p->data = map[p->data];

}

void

list_remap_head(struct list_head *head, uint32_t *map)

{

	if (head->flags == RAZOR_IMMEDIATE)

		head->list_ptr = map[head->list_ptr];

}

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);

}