src/vppinfra/hash.h

/*
 * Copyright (c) 2015 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.
 */
/*
  Copyright (c) 2001-2005 Eliot Dresselhaus

  Permission is hereby granted, free of charge, to any person obtaining
  a copy of this software and associated documentation files (the
  "Software"), to deal in the Software without restriction, including
  without limitation the rights to use, copy, modify, merge, publish,
  distribute, sublicense, and/or sell copies of the Software, and to
  permit persons to whom the Software is furnished to do so, subject to
  the following conditions:

  The above copyright notice and this permission notice shall be
  included in all copies or substantial portions of the Software.

  THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
  LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
  OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
  WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
*/

#ifndef included_hash_h
#define included_hash_h

#include <vppinfra/error.h>
#include <vppinfra/format.h>
#include <vppinfra/vec.h>
#include <vppinfra/vector.h>

struct hash_header;

typedef uword (hash_key_sum_function_t) (struct hash_header *, uword key);
typedef uword (hash_key_equal_function_t)
  (struct hash_header *, uword key1, uword key2);

/* Vector header for hash tables. */
typedef struct hash_header
{
  /* Number of elements in hash table. */
  uword elts;

  /* Flags as follows. */
  u32 flags;

  /* Set if user does not want table to auto-resize when sufficiently full. */
#define HASH_FLAG_NO_AUTO_GROW		(1 << 0)
  /* Set if user does not want table to auto-resize when sufficiently empty. */
#define HASH_FLAG_NO_AUTO_SHRINK	(1 << 1)
  /* Set when hash_next is in the process of iterating through this hash table. */
#define HASH_FLAG_HASH_NEXT_IN_PROGRESS (1 << 2)

  u32 log2_pair_size;

  /* Function to compute the "sum" of a hash key.
     Hash function is this sum modulo the prime size of
     the hash table (vec_len (v)). */
  hash_key_sum_function_t *key_sum;

  /* Special values for key_sum "function". */
#define KEY_FUNC_NONE		(0)	/*< sum = key */
#define KEY_FUNC_POINTER_UWORD	(1)	/*< sum = *(uword *) key */
#define KEY_FUNC_POINTER_U32	(2)	/*< sum = *(u32 *) key */
#define KEY_FUNC_STRING         (3)	/*< sum = string_key_sum, etc. */
#define KEY_FUNC_MEM		(4)	/*< sum = mem_key_sum */

  /* key comparison function */
  hash_key_equal_function_t *key_equal;

  /* Hook for user's data.  Used to parameterize sum/equal functions. */
  any user;

  /* Format a (k,v) pair */
  format_function_t *format_pair;

  /* Format function arg */
  void *format_pair_arg;

  /* Bit i is set if pair i is a user object (as opposed to being
     either zero or an indirect array of pairs). */
  uword is_user[0];
} hash_t;

/* Hash header size in bytes */
always_inline uword
hash_header_bytes (void *v)
{
  hash_t *h;
  uword is_user_bytes =
    (sizeof (h->is_user[0]) * vec_len (v)) / BITS (h->is_user[0]);
  return sizeof (h[0]) + is_user_bytes;
}

/* Returns a pointer to the hash header given the vector pointer */
always_inline hash_t *
hash_header (void *v)
{
  return vec_header (v, hash_header_bytes (v));
}

/* Number of elements in the hash table */
always_inline uword
hash_elts (void *v)
{
  hash_t *h = hash_header (v);
  return v ? h->elts : 0;
}

/* Number of elements the hash table can hold */
always_inline uword
hash_capacity (void *v)
{
  return vec_len (v);
}

/* Returns 1 if the hash pair contains user data */
always_inline uword
hash_is_user (void *v, uword i)
{
  hash_t *h = hash_header (v);
  uword i0 = i / BITS (h->is_user[0]);
  uword i1 = i % BITS (h->is_user[0]);
  return (h->is_user[i0] & ((uword) 1 << i1)) != 0;
}

/* Set the format function and format argument for a hash table */
always_inline void
hash_set_pair_format (void *v,
		      format_function_t * format_pair, void *format_pair_arg)
{
  hash_t *h = hash_header (v);
  h->format_pair = format_pair;
  h->format_pair_arg = format_pair_arg;
}

/* Set hash table flags */
always_inline void
hash_set_flags (void *v, uword flags)
{
  hash_header (v)->flags |= flags;
}

/* Key value pairs. */
typedef struct
{
  /* The Key */
  uword key;

  /* The Value. Length is 2^log2_pair_size - 1. */
  uword value[0];
} hash_pair_t;

/* The indirect pair structure

    If log2_pair_size > 0 we overload hash pairs
    with indirect pairs for buckets with more than one
    pair. */
typedef struct
{
  /* pair vector */
  hash_pair_t *pairs;
  /* padding */
  u8 pad[sizeof (uword) - sizeof (hash_pair_t *)];
  /* allocated length */
  uword alloc_len;
}
hash_pair_indirect_t;

/* Direct / Indirect pair union */
typedef union
{
  hash_pair_t direct;
  hash_pair_indirect_t indirect;
} hash_pair_union_t;

#define LOG2_ALLOC_BITS (5)
#define PAIR_BITS	(BITS (uword) - LOG2_ALLOC_BITS)

/* Log2 number of bytes allocated in pairs array. */
always_inline uword
indirect_pair_get_log2_bytes (hash_pair_indirect_t * p)
{
  return p->alloc_len >> PAIR_BITS;
}

/* Get the length of an indirect pair */
always_inline uword
indirect_pair_get_len (hash_pair_indirect_t * p)
{
  if (!p->pairs)
    return 0;
  else
    return p->alloc_len & (((uword) 1 << PAIR_BITS) - 1);
}

/* Set the length of an indirect pair */
always_inline void
indirect_pair_set (hash_pair_indirect_t * p, uword log2_alloc, uword len)
{
  ASSERT (len < ((uword) 1 << PAIR_BITS));
  ASSERT (log2_alloc < ((uword) 1 << LOG2_ALLOC_BITS));
  p->alloc_len = (log2_alloc << PAIR_BITS) | len;
}

/* internal routine to fetch value for given key */
uword *_hash_get (void *v, uword key);

/* internal routine to fetch value (key, value) pair for given key */
hash_pair_t *_hash_get_pair (void *v, uword key);

/* internal routine to unset a (key, value) pair */
void *_hash_unset (void *v, uword key, void *old_value);

/* internal routine to set a (key, value) pair, return the old value */
void *_hash_set3 (void *v, uword key, void *value, void *old_value);

/* Resize a hash table */
void *hash_resize (void *old, uword new_size);

/* duplicate a hash table */
void *hash_dup (void *old);

/* Returns the number of bytes used by a hash table */
uword hash_bytes (void *v);

/* Public macro to set a (key, value) pair, return the old value */
#define hash_set3(h,key,value,old_value)				\
({									\
  uword _v = (uword) (value);						\
  (h) = _hash_set3 ((h), (uword) (key), (void *) &_v, (old_value));	\
})

/* Public macro to fetch value for given key */
#define hash_get(h,key)		_hash_get ((h), (uword) (key))

/* Public macro to fetch value (key, value) pair for given key */
#define hash_get_pair(h,key)	_hash_get_pair ((h), (uword) (key))

/* Public macro to set a (key, value) pair */
#define hash_set(h,key,value)	hash_set3(h,key,value,0)

/* Public macro to set (key, 0) pair */
#define hash_set1(h,key)	(h) = _hash_set3(h,(uword) (key),0,0)

/* Public macro to unset a (key, value) pair */
#define hash_unset(h,key)	((h) = _hash_unset ((h), (uword) (key),0))

/* Public macro to unset a (key, value) pair, return the old value */
#define hash_unset3(h,key,old_value) ((h) = _hash_unset ((h), (uword) (key), (void *) (old_value)))

/* get/set/unset for pointer keys. */

/* Public macro to fetch value for given pointer key */
#define hash_get_mem(h,key)	_hash_get ((h), pointer_to_uword (key))

/* Public macro to fetch (key, value) for given pointer key */
#define hash_get_pair_mem(h,key) _hash_get_pair ((h), pointer_to_uword (key))

/* Public macro to set (key, value) for pointer key */
#define hash_set_mem(h,key,value) hash_set3 (h, pointer_to_uword (key), (value), 0)

/* Public inline function allocate and copy key to use in hash for pointer key */
always_inline void
hash_set_mem_alloc (uword ** h, void *key, uword v)
{
  size_t ksz = hash_header (*h)->user;
  void *copy = clib_mem_alloc (ksz);
  clib_memcpy (copy, key, ksz);
  hash_set_mem (*h, copy, v);
}

/* Public macro to set (key, 0) for pointer key */
#define hash_set1_mem(h,key)     hash_set3 ((h), pointer_to_uword (key), 0, 0)

/* Public macro to unset (key, value) for pointer key */
#define hash_unset_mem(h,key)    ((h) = _hash_unset ((h), pointer_to_uword (key),0))

/* Public inline function to unset pointer key and then free the key memory */
always_inline void
hash_unset_mem_free (uword ** h, void *key)
{
  hash_pair_t *hp = hash_get_pair_mem (*h, key);
  if (PREDICT_TRUE (hp != NULL))
    {
      key = uword_to_pointer (hp->key, void *);
      hash_unset_mem (*h, key);
      clib_mem_free (key);
    }
}

/* internal routine to free a hash table */
extern void *_hash_free (void *v);

/* Public macro to free a hash table */
#define hash_free(h) (h) = _hash_free ((h))

clib_error_t *hash_validate (void *v);

/* Public inline function to get the number of value bytes for a hash table */
always_inline uword
hash_value_bytes (hash_t * h)
{
  hash_pair_t *p;
  return (sizeof (p->value[0]) << h->log2_pair_size) - sizeof (p->key);
}

/* Public inline function to get log2(size of a (key,value) pair) */
always_inline uword
hash_pair_log2_bytes (hash_t * h)
{
  uword log2_bytes = h->log2_pair_size;
  ASSERT (BITS (hash_pair_t) == 32 || BITS (hash_pair_t) == 64);
  if (BITS (hash_pair_t) == 32)
    log2_bytes += 2;
  else if (BITS (hash_pair_t) == 64)
    log2_bytes += 3;
  return log2_bytes;
}

/* Public inline function to get size of a (key,value) pair */
always_inline uword
hash_pair_bytes (hash_t * h)
{
  return (uword) 1 << hash_pair_log2_bytes (h);
}

/* Public inline function to advance a pointer past one (key,value) pair */
always_inline void *
hash_forward1 (hash_t * h, void *v)
{
  return (u8 *) v + hash_pair_bytes (h);
}

/* Public inline function to advance a pointer past N (key,value) pairs */
always_inline void *
hash_forward (hash_t * h, void *v, uword n)
{
  return (u8 *) v + ((n * sizeof (hash_pair_t)) << h->log2_pair_size);
}

/** Iterate over hash pairs.

    @param p    The current (key,value) pair. This should be of type
                <code>(hash_pair_t *)</code>.
    @param v    The hash table to iterate.
    @param body The operation to perform on each (key,value) pair.

    Executes the expression or code block @c body with each active hash pair.
*/
/* A previous version of this macro made use of the hash_pair_union_t
 * structure; this version does not since that approach mightily upset
 * the static analysis tool. In the rare chance someone is reading this
 * code, pretend that _p below is of type hash_pair_union_t and that when
 * used as an rvalue it's really using one of the union members as the
 * rvalue. If you were confused before you might be marginally less
 * confused after.
 */
#define hash_foreach_pair(p,v,body)                                         \
do {                                                                        \
 __label__ _hash_foreach_done;                                              \
  hash_t * _h = hash_header (v);                                            \
  void * _p;                                                                \
  hash_pair_t * _q, * _q_end;                                               \
  uword _i, _i1, _id, _pair_increment;                                      \
                                                                            \
  _p = (v);                                                                 \
  _i = 0;                                                                   \
  _pair_increment = 1;                                                      \
  if ((v))                                                                  \
      _pair_increment = 1 << _h->log2_pair_size;                            \
  while (_i < hash_capacity (v))                                            \
    {                                                                       \
      _id = _h->is_user[_i / BITS (_h->is_user[0])];                        \
      _i1 = _i + BITS (_h->is_user[0]);                                     \
                                                                            \
      do {                                                                  \
        if (_id & 1)                                                        \
          {                                                                 \
            _q = _p;                                                        \
            _q_end = _q + _pair_increment;                                  \
          }                                                                 \
        else                                                                \
          {                                                                 \
            hash_pair_indirect_t * _pi = _p;                                \
            _q = _pi->pairs;                                                \
            if (_h->log2_pair_size > 0)                                     \
              _q_end = hash_forward (_h, _q, indirect_pair_get_len (_pi));  \
            else                                                            \
              _q_end = vec_end (_q);                                        \
          }                                                                 \
                                                                            \
        /* Loop through all elements in bucket.                             \
           Bucket may have 0 1 or more (indirect case) pairs. */            \
        while (_q < _q_end)                                                 \
          {                                                                 \
            uword _break_in_body = 1;                                       \
            (p) = _q;                                                       \
            do {                                                            \
              body;                                                         \
              _break_in_body = 0;                                           \
            } while (0);                                                    \
            if (_break_in_body)                                             \
              goto _hash_foreach_done;                                      \
            _q += _pair_increment;                                          \
          }                                                                 \
                                                                            \
        _p = (hash_pair_t *)_p + _pair_increment;                           \
        _id = _id / 2;                                                      \
        _i++;                                                               \
      } while (_i < _i1);                                                   \
    }                                                                       \
  _hash_foreach_done:                                                       \
  /* Be silent Mr. Compiler-Warning. */                                     \
  ;                                                                         \
 } while (0)

/* Iterate over key/value pairs

    @param key_var the current key
    @param value_var the current value
    @param h the hash table to iterate across
    @param body the operation to perform on each (key_var,value_var) pair.

    calls body with each active hash pair
*/
/* Iterate over key/value pairs. */
#define hash_foreach(key_var,value_var,h,body)			\
do {								\
  hash_pair_t * _r;						\
  hash_foreach_pair (_r, (h), {					\
    (key_var) = (__typeof__ (key_var)) _r->key;			\
    (value_var) = (__typeof__ (value_var)) _r->value[0];	\
    do { body; } while (0);					\
  });								\
} while (0)

/* Iterate over key/value pairs for pointer key hash tables

    @param key_var the current key
    @param value_var the current value
    @param h the hash table to iterate across
    @param body the operation to perform on each (key_var,value_var) pair.

    calls body with each active hash pair
*/
#define hash_foreach_mem(key_var,value_var,h,body)			\
do {									\
  hash_pair_t * _r;							\
  hash_foreach_pair (_r, (h), {						\
    (key_var) = (__typeof__ (key_var)) uword_to_pointer (_r->key, void *); \
    (value_var) = (__typeof__ (value_var)) _r->value[0];		\
    do { body; } while (0);						\
  });									\
} while (0)

/* Support for iteration through hash table. */

/* This struct saves iteration state for hash_next.
   None of these fields are meant to be visible to the user.
   Hence, the cryptic short-hand names. */
typedef struct
{
  uword i, j, f;
} hash_next_t;

hash_pair_t *hash_next (void *v, hash_next_t * hn);

void *_hash_create (uword elts, hash_t * h);

always_inline void
hash_set_value_bytes (hash_t * h, uword value_bytes)
{
  hash_pair_t *p;
  h->log2_pair_size =
    max_log2 ((sizeof (p->key) + value_bytes + sizeof (p->key) -
	       1) / sizeof (p->key));
}

#define hash_create2(_elts,_user,_value_bytes,               \
                     _key_sum,_key_equal,                    \
                     _format_pair,_format_pair_arg)          \
({							     \
  hash_t _h;						     \
  clib_memset (&_h, 0, sizeof (_h));				     \
  _h.user = (_user);				             \
  _h.key_sum   = (hash_key_sum_function_t *) (_key_sum);     \
  _h.key_equal = (_key_equal);				     \
  hash_set_value_bytes (&_h, (_value_bytes));		     \
  _h.format_pair = (format_function_t *) (_format_pair);     \
  _h.format_pair_arg = (_format_pair_arg);                   \
  _hash_create ((_elts), &_h);				     \
})

/* Hash function based on that of Bob Jenkins (bob_jenkins@compuserve.com).
   Public domain per: http://www.burtleburtle.net/bob/hash/doobs.html
   Thanks, Bob. */

#define hash_mix_step(a,b,c,s0,s1,s2)		\
do {						\
  (a) -= (b) + (c); (a) ^= (c) >> (s0);		\
  (b) -= (c) + (a); (b) ^= (a) << (s1);		\
  (c) -= (a) + (b); (c) ^= (b) >> (s2);		\
} while (0)

#define hash_mix32_step_1(a,b,c) hash_mix_step(a,b,c,13,8,13)
#define hash_mix32_step_2(a,b,c) hash_mix_step(a,b,c,12,16,5)
#define hash_mix32_step_3(a,b,c) hash_mix_step(a,b,c,3,10,15)

#define hash_mix64_step_1(a,b,c) hash_mix_step(a,b,c,43,9,8)
#define hash_mix64_step_2(a,b,c) hash_mix_step(a,b,c,38,23,5)
#define hash_mix64_step_3(a,b,c) hash_mix_step(a,b,c,35,49,11)
#define hash_mix64_step_4(a,b,c) hash_mix_step(a,b,c,12,18,22)

/* Hash function based on that of Bob Jenkins (bob_jenkins@compuserve.com).
   Thanks, Bob. */
#define hash_mix64(a0,b0,c0)			\
do {						\
  hash_mix64_step_1 (a0, b0, c0);		\
  hash_mix64_step_2 (a0, b0, c0);		\
  hash_mix64_step_3 (a0, b0, c0);		\
  hash_mix64_step_4 (a0, b0, c0);		\
} while (0)					\

#define hash_mix32(a0,b0,c0)			\
do {						\
  hash_mix32_step_1 (a0, b0, c0);		\
  hash_mix32_step_2 (a0, b0, c0);		\
  hash_mix32_step_3 (a0, b0, c0);		\
} while (0)					\

/* Finalize from Bob Jenkins lookup3.c */

always_inline uword
hash32_rotate_left (u32 x, u32 i)
{
  return (x << i) | (x >> (BITS (i) - i));
}

#define hash_v3_mix32(a,b,c)					\
do {								\
  (a) -= (c); (a) ^= hash32_rotate_left ((c), 4); (c) += (b);	\
  (b) -= (a); (b) ^= hash32_rotate_left ((a), 6); (a) += (c);	\
  (c) -= (b); (c) ^= hash32_rotate_left ((b), 8); (b) += (a);	\
  (a) -= (c); (a) ^= hash32_rotate_left ((c),16); (c) += (b);	\
  (b) -= (a); (b) ^= hash32_rotate_left ((a),19); (a) += (c);	\
  (c) -= (b); (c) ^= hash32_rotate_left ((b), 4); (b) += (a);	\
} while (0)

#define hash_v3_finalize32(a,b,c)			\
do {							\
  (c) ^= (b); (c) -= hash32_rotate_left ((b), 14);	\
  (a) ^= (c); (a) -= hash32_rotate_left ((c), 11);	\
  (b) ^= (a); (b) -= hash32_rotate_left ((a), 25);	\
  (c) ^= (b); (c) -= hash32_rotate_left ((b), 16);	\
  (a) ^= (c); (a) -= hash32_rotate_left ((c),  4);	\
  (b) ^= (a); (b) -= hash32_rotate_left ((a), 14);	\
  (c) ^= (b); (c) -= hash32_rotate_left ((b), 24);	\
} while (0)

/* 32 bit mixing/finalize in steps. */

#define hash_v3_mix32_step1(a,b,c)				\
do {								\
  (a) -= (c); (a) ^= hash32_rotate_left ((c), 4); (c) += (b);	\
  (b) -= (a); (b) ^= hash32_rotate_left ((a), 6); (a) += (c);	\
} while (0)

#define hash_v3_mix32_step2(a,b,c)				\
do {								\
  (c) -= (b); (c) ^= hash32_rotate_left ((b), 8); (b) += (a);	\
  (a) -= (c); (a) ^= hash32_rotate_left ((c),16); (c) += (b);	\
} while (0)

#define hash_v3_mix32_step3(a,b,c)				\
do {								\
  (b) -= (a); (b) ^= hash32_rotate_left ((a),19); (a) += (c);	\
  (c) -= (b); (c) ^= hash32_rotate_left ((b), 4); (b) += (a);	\
} while (0)

#define hash_v3_finalize32_step1(a,b,c)			\
do {							\
  (c) ^= (b); (c) -= hash32_rotate_left ((b), 14);	\
  (a) ^= (c); (a) -= hash32_rotate_left ((c), 11);	\
} while (0)

#define hash_v3_finalize32_step2(a,b,c)			\
do {							\
  (b) ^= (a); (b) -= hash32_rotate_left ((a), 25);	\
  (c) ^= (b); (c) -= hash32_rotate_left ((b), 16);	\
} while (0)

#define hash_v3_finalize32_step3(a,b,c)			\
do {							\
  (a) ^= (c); (a) -= hash32_rotate_left ((c),  4);	\
  (b) ^= (a); (b) -= hash32_rotate_left ((a), 14);	\
  (c) ^= (b); (c) -= hash32_rotate_left ((b), 24);	\
} while (0)

/* Vector v3 mixing/finalize. */
#define hash_v3_mix_step_1_u32x(a,b,c)				\
do {								\
  (a) -= (c); (a) ^= u32x_irotate_left ((c), 4); (c) += (b);	\
  (b) -= (a); (b) ^= u32x_irotate_left ((a), 6); (a) += (c);	\
  (c) -= (b); (c) ^= u32x_irotate_left ((b), 8); (b) += (a);	\
} while (0)

#define hash_v3_mix_step_2_u32x(a,b,c)				\
do {								\
  (a) -= (c); (a) ^= u32x_irotate_left ((c),16); (c) += (b);	\
  (b) -= (a); (b) ^= u32x_irotate_left ((a),19); (a) += (c);	\
  (c) -= (b); (c) ^= u32x_irotate_left ((b), 4); (b) += (a);	\
} while (0)

#define hash_v3_finalize_step_1_u32x(a,b,c)		\
do {							\
  (c) ^= (b); (c) -= u32x_irotate_left ((b), 14);	\
  (a) ^= (c); (a) -= u32x_irotate_left ((c), 11);	\
  (b) ^= (a); (b) -= u32x_irotate_left ((a), 25);	\
} while (0)

#define hash_v3_finalize_step_2_u32x(a,b,c)		\
do {							\
  (c) ^= (b); (c) -= u32x_irotate_left ((b), 16);	\
  (a) ^= (c); (a) -= u32x_irotate_left ((c),  4);	\
  (b) ^= (a); (b) -= u32x_irotate_left ((a), 14);	\
  (c) ^= (b); (c) -= u32x_irotate_left ((b), 24);	\
} while (0)

#define hash_v3_mix_u32x(a,b,c)			\
do {						\
  hash_v3_mix_step_1_u32x(a,b,c);		\
  hash_v3_mix_step_2_u32x(a,b,c);		\
} while (0)

#define hash_v3_finalize_u32x(a,b,c)		\
do {						\
  hash_v3_finalize_step_1_u32x(a,b,c);		\
  hash_v3_finalize_step_2_u32x(a,b,c);		\
} while (0)

extern uword hash_memory (void *p, word n_bytes, uword state);

extern uword mem_key_sum (hash_t * h, uword key);
extern uword mem_key_equal (hash_t * h, uword key1, uword key2);

#define hash_create_mem(elts,key_bytes,value_bytes)	\
  hash_create2((elts),(key_bytes),(value_bytes),mem_key_sum,mem_key_equal,0,0)

extern uword vec_key_sum (hash_t * h, uword key);
extern uword vec_key_equal (hash_t * h, uword key1, uword key2);
extern u8 *vec_key_format_pair (u8 * s, va_list * args);

#define hash_create_vec(elts,key_bytes,value_bytes)	\
  hash_create2((elts),(key_bytes),(value_bytes),\
               vec_key_sum,vec_key_equal,vec_key_format_pair,0)

extern uword string_key_sum (hash_t * h, uword key);
extern uword string_key_equal (hash_t * h, uword key1, uword key2);
extern u8 *string_key_format_pair (u8 * s, va_list * args);

/*
 * Note: if you plan to put a hash into shared memory,
 * the key sum and key equal functions MUST be set to magic constants!
 * PIC means that whichever process sets up the hash won't have
 * the actual key sum functions at the same place, leading to
 * very hard-to-find bugs...
 */

#define hash_create_shmem(elts,key_bytes,value_bytes)           \
  hash_create2((elts),(key_bytes),(value_bytes),                \
               (hash_key_sum_function_t *) KEY_FUNC_MEM,        \
               (hash_key_equal_function_t *)KEY_FUNC_MEM,       \
               0, 0)

#define hash_create_string(elts,value_bytes)                    \
  hash_create2((elts),0,(value_bytes),                          \
               (hash_key_sum_function_t *) KEY_FUNC_STRING,     \
               (hash_key_equal_function_t *)KEY_FUNC_STRING,    \
               0, 0)

#define hash_create(elts,value_bytes)				\
  hash_create2((elts),0,(value_bytes),				\
               (hash_key_sum_function_t *) KEY_FUNC_NONE,	\
               (hash_key_equal_function_t *) KEY_FUNC_NONE,	\
               0,0)

#define hash_create_uword(elts,value_bytes)				\
  hash_create2((elts),0,(value_bytes),					\
               (hash_key_sum_function_t *) KEY_FUNC_POINTER_UWORD,	\
               (hash_key_equal_function_t *) KEY_FUNC_POINTER_UWORD,	\
               0,0)

#define hash_create_u32(elts,value_bytes)				\
  hash_create2((elts),0,(value_bytes),					\
               (hash_key_sum_function_t *) KEY_FUNC_POINTER_U32,	\
               (hash_key_equal_function_t *) KEY_FUNC_POINTER_U32,	\
               0,0)

u8 *format_hash (u8 * s, va_list * va);

/* Looks up input in hash table indexed by either vec string or
   c string (null terminated). */
unformat_function_t unformat_hash_vec_string;
unformat_function_t unformat_hash_string;

/* Main test routine. */
int test_hash_main (unformat_input_t * input);

#endif /* included_hash_h */

/*
 * fd.io coding-style-patch-verification: ON
 *
 * Local Variables:
 * eval: (c-set-style "gnu")
 * End:
 */