// -*- c-basic-offset: 8; indent-tabs-mode: t -*-
// vim:ts=8:sw=8:noet:ai:
/*
 * Copyright (C) 2006 Evgeniy Stepanov <eugeni.stepanov@gmail.com>
 *
 * This file is part of libass.
 *
 * libass 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.
 *
 * libass 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 libass; if not, write to the Free Software Foundation, Inc.,
 * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
 */

#include "config.h"

#include <inttypes.h>
#include <ft2build.h>
#include FT_FREETYPE_H
#include FT_GLYPH_H

#include <assert.h>

#include "mputils.h"
#include "ass.h"
#include "ass_fontconfig.h"
#include "ass_font.h"
#include "ass_bitmap.h"
#include "ass_cache.h"


typedef struct hashmap_item_s {
	void* key;
	void* value;
	struct hashmap_item_s* next;
} hashmap_item_t;
typedef hashmap_item_t* hashmap_item_p;

struct hashmap_s {
	int nbuckets;
	size_t key_size, value_size;
	hashmap_item_p* root;
	hashmap_item_dtor_t item_dtor; // a destructor for hashmap key/value pairs
	hashmap_key_compare_t key_compare;
	hashmap_hash_t hash;
	// stats
	int hit_count;
	int miss_count;
	int count;
};

#define FNV1_32A_INIT (unsigned)0x811c9dc5

static inline unsigned fnv_32a_buf(void* buf, size_t len, unsigned hval)
{
	unsigned char *bp = buf;
	unsigned char *be = bp + len;
	while (bp < be) {
		hval ^= (unsigned)*bp++;
		hval += (hval<<1) + (hval<<4) + (hval<<7) + (hval<<8) + (hval<<24);
	}
	return hval;
}
static inline unsigned fnv_32a_str(char* str, unsigned hval)
{
	unsigned char* s = (unsigned char*)str;
	while (*s) {
		hval ^= (unsigned)*s++;
		hval += (hval<<1) + (hval<<4) + (hval<<7) + (hval<<8) + (hval<<24);
	}
	return hval;
}

static unsigned hashmap_hash(void* buf, size_t len)
{
	return fnv_32a_buf(buf, len, FNV1_32A_INIT);
}

static int hashmap_key_compare(void* a, void* b, size_t size)
{
	return memcmp(a, b, size) == 0;
}

static void hashmap_item_dtor(void* key, size_t key_size, void* value, size_t value_size)
{
	free(key);
	free(value);
}

hashmap_t* hashmap_init(size_t key_size, size_t value_size, int nbuckets,
			hashmap_item_dtor_t item_dtor, hashmap_key_compare_t key_compare,
			hashmap_hash_t hash)
{
	hashmap_t* map = calloc(1, sizeof(hashmap_t));
	map->nbuckets = nbuckets;
	map->key_size = key_size;
	map->value_size = value_size;
	map->root = calloc(nbuckets, sizeof(hashmap_item_p));
	map->item_dtor = item_dtor ? item_dtor : hashmap_item_dtor;
	map->key_compare = key_compare ? key_compare : hashmap_key_compare;
	map->hash = hash ? hash : hashmap_hash;
	return map;
}

void hashmap_done(hashmap_t* map)
{
	int i;
	// print stats
	if (map->count > 0 || map->hit_count + map->miss_count > 0)
		mp_msg(MSGT_ASS, MSGL_V, "cache statistics: \n  total accesses: %d\n  hits: %d\n  misses: %d\n  object count: %d\n",
		       map->hit_count + map->miss_count, map->hit_count, map->miss_count, map->count);
	
	for (i = 0; i < map->nbuckets; ++i) {
		hashmap_item_t* item = map->root[i];
		while (item) {
			hashmap_item_t* next = item->next;
			map->item_dtor(item->key, map->key_size, item->value, map->value_size);
			free(item);
			item = next;
		}
	}
	free(map->root);
	free(map);
}

// does nothing if key already exists
void* hashmap_insert(hashmap_t* map, void* key, void* value)
{
	unsigned hash = map->hash(key, map->key_size);
	hashmap_item_t** next = map->root + (hash % map->nbuckets);
	while (*next) {
		if (map->key_compare(key, (*next)->key, map->key_size))
			return (*next)->value;
		next = &((*next)->next);
		assert(next);
	}
	(*next) = malloc(sizeof(hashmap_item_t));
	(*next)->key = malloc(map->key_size);
	(*next)->value = malloc(map->value_size);
	memcpy((*next)->key, key, map->key_size);
	memcpy((*next)->value, value, map->value_size);
	(*next)->next = 0;

	map->count ++;
	return (*next)->value;
}

void* hashmap_find(hashmap_t* map, void* key)
{
	unsigned hash = map->hash(key, map->key_size);
	hashmap_item_t* item = map->root[hash % map->nbuckets];
	while (item) {
		if (map->key_compare(key, item->key, map->key_size)) {
			map->hit_count++;
			return item->value;
		}
		item = item->next;
	}
	map->miss_count++;
	return 0;
}

//---------------------------------
// font cache

hashmap_t* font_cache;

static unsigned font_desc_hash(void* buf, size_t len)
{
	ass_font_desc_t* desc = buf;
	unsigned hval;
	hval = fnv_32a_str(desc->family, FNV1_32A_INIT);
	hval = fnv_32a_buf(&desc->bold, sizeof(desc->bold), hval);
	hval = fnv_32a_buf(&desc->italic, sizeof(desc->italic), hval);
	return hval;
}

static int font_compare(void* key1, void* key2, size_t key_size) {
	ass_font_desc_t* a = key1;
	ass_font_desc_t* b = key2;
	if (strcmp(a->family, b->family) != 0)
		return 0;
	if (a->bold != b->bold)
		return 0;
	if (a->italic != b->italic)
		return 0;
	return 1;
}

static void font_hash_dtor(void* key, size_t key_size, void* value, size_t value_size)
{
	ass_font_free(value);
	free(key);
}

ass_font_t* ass_font_cache_find(ass_font_desc_t* desc)
{
	return hashmap_find(font_cache, desc);
}

/**
 * \brief Add a face struct to cache.
 * \param font font struct
*/
void* ass_font_cache_add(ass_font_t* font)
{
	return hashmap_insert(font_cache, &(font->desc), font);
}

void ass_font_cache_init(void)
{
	font_cache = hashmap_init(sizeof(ass_font_desc_t),
				  sizeof(ass_font_t),
				  1000,
				  font_hash_dtor, font_compare, font_desc_hash);
}

void ass_font_cache_done(void)
{
	hashmap_done(font_cache);
}

//---------------------------------
// bitmap cache

hashmap_t* bitmap_cache;

static void bitmap_hash_dtor(void* key, size_t key_size, void* value, size_t value_size)
{
	bitmap_hash_val_t* v = value;
	if (v->bm) ass_free_bitmap(v->bm);
	if (v->bm_o) ass_free_bitmap(v->bm_o);
	if (v->bm_s) ass_free_bitmap(v->bm_s);
	free(key);
	free(value);
}

void* cache_add_bitmap(bitmap_hash_key_t* key, bitmap_hash_val_t* val)
{
	return hashmap_insert(bitmap_cache, key, val);
}

/**
 * \brief Get a bitmap from bitmap cache.
 * \param key hash key
 * \return requested hash val or 0 if not found
*/ 
bitmap_hash_val_t* cache_find_bitmap(bitmap_hash_key_t* key)
{
	return hashmap_find(bitmap_cache, key);
}

void ass_bitmap_cache_init(void)
{
	bitmap_cache = hashmap_init(sizeof(bitmap_hash_key_t),
				   sizeof(bitmap_hash_val_t),
				   0xFFFF + 13,
				   bitmap_hash_dtor, NULL, NULL);
}

void ass_bitmap_cache_done(void)
{
	hashmap_done(bitmap_cache);
}

void ass_bitmap_cache_reset(void)
{
	ass_bitmap_cache_done();
	ass_bitmap_cache_init();
}

//---------------------------------
// glyph cache

hashmap_t* glyph_cache;

static void glyph_hash_dtor(void* key, size_t key_size, void* value, size_t value_size)
{
	glyph_hash_val_t* v = value;
	if (v->glyph) FT_Done_Glyph(v->glyph);
	if (v->outline_glyph) FT_Done_Glyph(v->outline_glyph);
	free(key);
	free(value);
}

void* cache_add_glyph(glyph_hash_key_t* key, glyph_hash_val_t* val)
{
	return hashmap_insert(glyph_cache, key, val);
}

/**
 * \brief Get a glyph from glyph cache.
 * \param key hash key
 * \return requested hash val or 0 if not found
*/ 
glyph_hash_val_t* cache_find_glyph(glyph_hash_key_t* key)
{
	return hashmap_find(glyph_cache, key);
}

void ass_glyph_cache_init(void)
{
	glyph_cache = hashmap_init(sizeof(glyph_hash_key_t),
				   sizeof(glyph_hash_val_t),
				   0xFFFF + 13,
				   glyph_hash_dtor, NULL, NULL);
}

void ass_glyph_cache_done(void)
{
	hashmap_done(glyph_cache);
}

void ass_glyph_cache_reset(void)
{
	ass_glyph_cache_done();
	ass_glyph_cache_init();
}