/*
// Copyright (c) 2010-2017 Intel Corporation
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//     http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
*/

#include <string.h>
#include <rte_hash_crc.h>
#include <rte_table_hash.h>
#include <rte_version.h>

#include "hash_utils.h"

/* These opaque structure definitions were copied from DPDK lib/librte_table/rte_table_hash_key8.c */

struct rte_bucket_4_8 {
	/* Cache line 0 */
	uint64_t signature;
	uint64_t lru_list;
	struct rte_bucket_4_8 *next;
	uint64_t next_valid;

	uint64_t key[4];

	/* Cache line 1 */
	uint8_t data[0];
};

struct rte_table_hash_key8 {
#if RTE_VERSION >= RTE_VERSION_NUM(2,1,0,0)
	struct rte_table_stats stats;
#endif
	/* Input parameters */
	uint32_t n_buckets;
	uint32_t n_entries_per_bucket;
	uint32_t key_size;
	uint32_t entry_size;
	uint32_t bucket_size;
	uint32_t signature_offset;
	uint32_t key_offset;
#if RTE_VERSION >= RTE_VERSION_NUM(2,2,0,0)
	uint64_t key_mask;
#endif
	rte_table_hash_op_hash f_hash;
	uint64_t seed;

	/* Extendible buckets */
	uint32_t n_buckets_ext;
	uint32_t stack_pos;
	uint32_t *stack;

	/* Lookup table */
	uint8_t memory[0] __rte_cache_aligned;
};

/* These opaque structure definitions were copied from DPDK lib/librte_table/rte_table_hash_ext.c */

struct bucket {
	union {
		uintptr_t next;
		uint64_t lru_list;
	};
	uint16_t sig[4];
	uint32_t key_pos[4];
};

#define BUCKET_NEXT(bucket)						\
	((void *) ((bucket)->next & (~1LU)))

struct grinder {
	struct bucket *bkt;
	uint64_t sig;
	uint64_t match;
	uint32_t key_index;
};

struct rte_table_hash_ext {
#if RTE_VERSION >= RTE_VERSION_NUM(2,1,0,0)
	struct rte_table_stats stats;
#endif
	/* Input parameters */
	uint32_t key_size;
	uint32_t entry_size;
	uint32_t n_keys;
	uint32_t n_buckets;
	uint32_t n_buckets_ext;
	rte_table_hash_op_hash f_hash;
	uint64_t seed;
	uint32_t signature_offset;
	uint32_t key_offset;

	/* Internal */
	uint64_t bucket_mask;
	uint32_t key_size_shl;
	uint32_t data_size_shl;
	uint32_t key_stack_tos;
	uint32_t bkt_ext_stack_tos;

	/* Grinder */
	struct grinder grinders[64];

	/* Tables */
	struct bucket *buckets;
	struct bucket *buckets_ext;
	uint8_t *key_mem;
	uint8_t *data_mem;
	uint32_t *key_stack;
	uint32_t *bkt_ext_stack;

	/* Table memory */
	uint8_t memory[0] __rte_cache_aligned;
};

uint64_t get_bucket(void* table, uint32_t bucket_idx, void** key, void** entries)
{
	struct rte_table_hash_ext *t = (struct rte_table_hash_ext *) table;
	struct bucket *bkt0, *bkt, *bkt_prev;
	uint64_t sig;
	uint32_t bkt_index, i;
	uint8_t n = 0;
	bkt_index = bucket_idx & t->bucket_mask;
	bkt0 = &t->buckets[bkt_index];
	sig = (bucket_idx >> 16) | 1LLU;

	/* Key is present in the bucket */
	for (bkt = bkt0; bkt != NULL; bkt = BUCKET_NEXT(bkt)) {
		for (i = 0; i < 4; i++) {
			uint64_t bkt_sig = (uint64_t) bkt->sig[i];
			uint32_t bkt_key_index = bkt->key_pos[i];
			uint8_t *bkt_key =
				&t->key_mem[bkt_key_index << t->key_size_shl];

			if (sig == bkt_sig) {
				key[n] = bkt_key;
				entries[n++] = &t->data_mem[bkt_key_index << t->data_size_shl];
				/* Assume no more than 4 entries in total (including extended state) */
				if (n == 4)
					return t->n_buckets;
			}
		}
	}
	return t->n_buckets;
}

uint64_t get_bucket_key8(void* table, uint32_t bucket_idx, void** key, void** entries)
{
	struct rte_bucket_4_8 *bucket, *bucket0;
	struct rte_table_hash_key8* f = table;
	uint8_t n = 0;

	bucket0 = (struct rte_bucket_4_8 *) &f->memory[bucket_idx * f->bucket_size];
	for (bucket = bucket0; bucket != NULL; bucket = bucket->next) {
		uint64_t mask;

		for (uint8_t i = 0, mask = 1LLU; i < 4; i++, mask <<= 1) {
			uint64_t bucket_signature = bucket->signature;

			if (bucket_signature & mask) {
				key[n] = &bucket->key[i];
				entries[n++] = &bucket->data[i *f->entry_size];
				/* Assume no more than 4 entries
				   in total (including extended state) */
				if (n == 4)
					return f->n_buckets;
			}
		}
	}
	return f->n_buckets;
}

uint64_t hash_crc32(void* key, uint32_t key_size, uint64_t seed)
{
	return rte_hash_crc(key, key_size, seed);
}