bihash_template.h

Go to the documentation of this file.

/*
  Copyright (c) 2014 Cisco and/or its affiliates.

  * 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.
*/

/* 
 * Note: to instantiate the template multiple times in a single file,
 * #undef __included_bihash_template_h__...
 */
#ifndef __included_bihash_template_h__
#define __included_bihash_template_h__

#include <vppinfra/heap.h>
#include <vppinfra/format.h>
#include <vppinfra/pool.h>

#ifndef BIHASH_TYPE
#error BIHASH_TYPE not defined
#endif

#define _bv(a,b) a##b
#define __bv(a,b) _bv(a,b)
#define BV(a) __bv(a,BIHASH_TYPE)

#define _bvt(a,b) a##b##_t
#define __bvt(a,b) _bvt(a,b)
#define BVT(a) __bvt(a,BIHASH_TYPE)

typedef struct BV(clib_bihash_value) {
  union {
    BVT(clib_bihash_kv) kvp[BIHASH_KVP_PER_PAGE];
    struct BV(clib_bihash_value) * next_free;
  };
} BVT(clib_bihash_value);

/* 
 * This is shared across all uses of the template, so it needs
 * a "personal" #include recursion block
 */
#ifndef __defined_clib_bihash_bucket_t__
#define __defined_clib_bihash_bucket_t__
typedef struct {
  union {
    struct {
      u32 offset;
      u8 pad[3];
      u8 log2_pages;
    };
    u64 as_u64;
  };
} clib_bihash_bucket_t;
#endif /* __defined_clib_bihash_bucket_t__ */

typedef struct {
  BVT(clib_bihash_value) * values;
  clib_bihash_bucket_t * buckets;
  volatile u32 * writer_lock;

  BVT(clib_bihash_value) ** working_copies;
  clib_bihash_bucket_t saved_bucket;

  u32 nbuckets;
  u32 log2_nbuckets;
  u8 * name;

  BVT(clib_bihash_value) **freelists;
  void * mheap;

} BVT(clib_bihash);


static inline void * 
BV(clib_bihash_get_value) (BVT(clib_bihash) * h, uword offset)
{
  u8 * hp = h->mheap;
  u8 * vp = hp + offset;

  return (void *) vp;
}

static inline uword BV(clib_bihash_get_offset) (BVT(clib_bihash) * h, void * v)
{
  u8 * hp, * vp;

  hp = (u8 *) h->mheap;
  vp = (u8 *) v;

  ASSERT((vp - hp) < 0x100000000ULL);
  return vp - hp;
}

void BV(clib_bihash_init)
     (BVT(clib_bihash) * h, char * name, u32 nbuckets, uword memory_size);

void BV(clib_bihash_free) 
     (BVT(clib_bihash) * h);

int BV(clib_bihash_add_del) (BVT(clib_bihash) * h, 
                             BVT(clib_bihash_kv) * add_v,
                             int is_add);
int BV(clib_bihash_search) (BVT(clib_bihash) * h, 
                            BVT(clib_bihash_kv) * search_v,
                            BVT(clib_bihash_kv) * return_v);

void BV(clib_bihash_foreach_key_value_pair) (BVT(clib_bihash) * h,
                                             void *callback,
                                             void *arg);

format_function_t BV(format_bihash);
format_function_t BV(format_bihash_kvp);


static inline int BV(clib_bihash_search_inline) 
    (BVT(clib_bihash) * h, BVT(clib_bihash_kv) * kvp)
{
  u64 hash;
  u32 bucket_index;
  uword value_index;
  BVT(clib_bihash_value) * v;
  clib_bihash_bucket_t * b;
  int i;

  hash = BV(clib_bihash_hash) (kvp);

  bucket_index = hash & (h->nbuckets-1);
  b = &h->buckets[bucket_index];

  if (b->offset == 0)
    return -1;

  hash >>= h->log2_nbuckets;

  v = BV(clib_bihash_get_value) (h, b->offset);
  value_index = hash & ((1<<b->log2_pages)-1);
  v += value_index;
  
  for (i = 0; i < BIHASH_KVP_PER_PAGE; i++)
    {
      if (BV(clib_bihash_key_compare)(v->kvp[i].key, kvp->key))
        {
          *kvp = v->kvp[i];
          return 0;
        }
    }
  return -1;
}

static inline int BV(clib_bihash_search_inline_2) 
     (BVT(clib_bihash) * h, 
      BVT(clib_bihash_kv) *search_key,
      BVT(clib_bihash_kv) *valuep)
{
  u64 hash;
  u32 bucket_index;
  uword value_index;
  BVT(clib_bihash_value) * v;
  clib_bihash_bucket_t * b;
  int i;

  ASSERT(valuep);

  hash = BV(clib_bihash_hash) (search_key);

  bucket_index = hash & (h->nbuckets-1);
  b = &h->buckets[bucket_index];

  if (b->offset == 0)
    return -1;

  hash >>= h->log2_nbuckets;

  v = BV(clib_bihash_get_value) (h, b->offset);
  value_index = hash & ((1<<b->log2_pages)-1);
  v += value_index;
  
  for (i = 0; i < BIHASH_KVP_PER_PAGE; i++)
    {
      if (BV(clib_bihash_key_compare)(v->kvp[i].key, search_key->key))
        {
          *valuep = v->kvp[i];
          return 0;
        }
    }
  return -1;
}


#endif /* __included_bihash_template_h__ */