ibf.c File Reference

#include "platform.h"
#include "ibf.h"
#include "gnunet_util_lib.h"

Include dependency graph for ibf.c:

Go to the source code of this file.

Macros
#define	LOG(kind, ...)   GNUNET_log_from (kind, "setu", __VA_ARGS__)
#define	IBF_KEY_HASH_VAL(k)
	Compute the key's hash from the key. More...

Functions
struct IBF_Key	ibf_key_from_hashcode (const struct GNUNET_HashCode *hash)
	Create a key from a hashcode. More...
void	ibf_hashcode_from_key (struct IBF_Key key, struct GNUNET_HashCode *dst)
	Create a hashcode from a key, by replicating the key until the hascode is filled. More...
struct InvertibleBloomFilter *	ibf_create (uint32_t size, uint8_t hash_num)
	Create an invertible bloom filter. More...
static void	ibf_get_indices (const struct InvertibleBloomFilter *ibf, struct IBF_Key key, int *dst)
	Store unique bucket indices for the specified key in dst. More...
static void	ibf_insert_into (struct InvertibleBloomFilter *ibf, struct IBF_Key key, const int *buckets, int side)
void	ibf_insert (struct InvertibleBloomFilter *ibf, struct IBF_Key key)
	Insert a key into an IBF. More...
void	ibf_remove (struct InvertibleBloomFilter *ibf, struct IBF_Key key)
	Remove a key from an IBF. More...
static int	ibf_is_empty (struct InvertibleBloomFilter *ibf)
	Test is the IBF is empty, i.e. More...
int	ibf_decode (struct InvertibleBloomFilter *ibf, int *ret_side, struct IBF_Key *ret_id)
	Decode and remove an element from the IBF, if possible. More...
uint8_t	ibf_get_max_counter (struct InvertibleBloomFilter *ibf)
	Returns the minimal bytes needed to store the counter of the IBF. More...
void	ibf_write_slice (const struct InvertibleBloomFilter *ibf, uint32_t start, uint64_t count, void *buf, uint8_t counter_max_length)
	Write buckets from an ibf to a buffer. More...
void	pack_counter (const struct InvertibleBloomFilter *ibf, uint32_t start, uint64_t count, uint8_t *buf, uint8_t counter_max_length)
	Packs the counter to transmit only the smallest possible amount of bytes and preventing overflow of the counter. More...
void	unpack_counter (const struct InvertibleBloomFilter *ibf, uint32_t start, uint64_t count, uint8_t *buf, uint8_t counter_max_length)
	Unpacks the counter to transmit only the smallest possible amount of bytes and preventing overflow of the counter. More...
void	ibf_read_slice (const void *buf, uint32_t start, uint64_t count, struct InvertibleBloomFilter *ibf, uint8_t counter_max_length)
	Read buckets from a buffer into an ibf. More...
void	ibf_subtract (struct InvertibleBloomFilter *ibf1, const struct InvertibleBloomFilter *ibf2)
	Subtract ibf2 from ibf1, storing the result in ibf1. More...
struct InvertibleBloomFilter *	ibf_dup (const struct InvertibleBloomFilter *ibf)
	Create a copy of an IBF, the copy has to be destroyed properly. More...
void	ibf_destroy (struct InvertibleBloomFilter *ibf)
	Destroy all resources associated with the invertible bloom filter. More...

Macro Definition Documentation

LOG

#define LOG	(		kind,
			...
	)		GNUNET_log_from (kind, "setu", __VA_ARGS__)

Definition at line 31 of file ibf.c.

IBF_KEY_HASH_VAL

#define IBF_KEY_HASH_VAL

(

k

)

Value:

                                                                 (GNUNET_CRYPTO_crc32_n (&(k), sizeof(struct \
                                                                 IBF_KeyHash)))

Compute the key's hash from the key.

Redefine to use a different hash function.

Definition at line 38 of file ibf.c.

Function Documentation

ibf_key_from_hashcode()

struct IBF_Key ibf_key_from_hashcode

(

const struct GNUNET_HashCode *

hash

)

Create a key from a hashcode.

Parameters

hash	the hashcode

Returns

a key

Definition at line 48 of file ibf.c.

{
  return *(struct IBF_Key *) hash;
}

ibf_hashcode_from_key()

void ibf_hashcode_from_key	(	struct IBF_Key	key,
		struct GNUNET_HashCode *	dst
	)

Create a hashcode from a key, by replicating the key until the hascode is filled.

Parameters

key	the key
dst	hashcode to store the result in

Definition at line 62 of file ibf.c.

{
  struct IBF_Key *p;
  unsigned int i;
  const unsigned int keys_per_hashcode = sizeof(struct GNUNET_HashCode)
                                         / sizeof(struct IBF_Key);
 
  p = (struct IBF_Key *) dst;
  for (i = 0; i < keys_per_hashcode; i++)
    *p++ = key;
}

References key, and p.

ibf_create()

struct InvertibleBloomFilter * ibf_create	(	uint32_t	size,
		uint8_t	hash_num
	)

Create an invertible bloom filter.

Parameters

size	number of IBF buckets
hash_num	number of buckets one element is hashed in

Returns

the newly created invertible bloom filter, NULL on error

Definition at line 84 of file ibf.c.

{
  struct InvertibleBloomFilter *ibf;
 
  GNUNET_assert (0 != size);
 
  ibf = GNUNET_new (struct InvertibleBloomFilter);
  ibf->count = GNUNET_malloc_large (size * sizeof(uint64_t));
  if (NULL == ibf->count)
  {
    GNUNET_free (ibf);
    return NULL;
  }
  ibf->key_sum = GNUNET_malloc_large (size * sizeof(struct IBF_Key));
  if (NULL == ibf->key_sum)
  {
    GNUNET_free (ibf->count);
    GNUNET_free (ibf);
    return NULL;
  }
  ibf->key_hash_sum = GNUNET_malloc_large (size * sizeof(struct IBF_KeyHash));
  if (NULL == ibf->key_hash_sum)
  {
    GNUNET_free (ibf->key_sum);
    GNUNET_free (ibf->count);
    GNUNET_free (ibf);
    return NULL;
  }
  ibf->size = size;
  ibf->hash_num = hash_num;
 
  return ibf;
}

References InvertibleBloomFilter::count, GNUNET_assert, GNUNET_free, GNUNET_malloc_large, GNUNET_new, hash_num, InvertibleBloomFilter::hash_num, InvertibleBloomFilter::key_hash_sum, InvertibleBloomFilter::key_sum, InvertibleBloomFilter::size, and size.

ibf_get_indices()

static void ibf_get_indices ( const struct InvertibleBloomFilter *  ibf, struct IBF_Key  key, int *  dst  )

static

Store unique bucket indices for the specified key in dst.

Definition at line 123 of file ibf.c.

{
  uint32_t filled;
  uint32_t i;
  uint32_t bucket;
 
  bucket = GNUNET_CRYPTO_crc32_n (&key, sizeof key);
  for (i = 0, filled = 0; filled < ibf->hash_num; i++)
  {
    uint64_t x;
 
    for (unsigned int j = 0; j < filled; j++)
      if (dst[j] == bucket % ibf->size)
        goto try_next;
    dst[filled++] = bucket % ibf->size;
try_next:
    x = ((uint64_t) bucket << 32) | i;
    bucket = GNUNET_CRYPTO_crc32_n (&x, sizeof x);
  }
}

References GNUNET_CRYPTO_crc32_n(), InvertibleBloomFilter::hash_num, key, and InvertibleBloomFilter::size.

Referenced by ibf_decode(), ibf_insert(), and ibf_remove().

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ibf_insert_into()

static void ibf_insert_into ( struct InvertibleBloomFilter *  ibf, struct IBF_Key  key, const int *  buckets, int  side  )

static

Definition at line 148 of file ibf.c.

{
  for (unsigned int i = 0; i < ibf->hash_num; i++)
  {
    const int bucket = buckets[i];
 
    ibf->count[bucket].count_val += side;
    ibf->key_sum[bucket].key_val ^= key.key_val;
    ibf->key_hash_sum[bucket].key_hash_val
      ^= IBF_KEY_HASH_VAL (key);
  }
}

References InvertibleBloomFilter::count, IBF_Count::count_val, InvertibleBloomFilter::hash_num, IBF_KEY_HASH_VAL, key, InvertibleBloomFilter::key_hash_sum, IBF_KeyHash::key_hash_val, InvertibleBloomFilter::key_sum, and IBF_Key::key_val.

Referenced by ibf_decode(), ibf_insert(), and ibf_remove().

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ibf_insert()

void ibf_insert	(	struct InvertibleBloomFilter *	ibf,
		struct IBF_Key	key
	)

Insert a key into an IBF.

Parameters

ibf	the IBF
key	the element's hash code

Definition at line 172 of file ibf.c.

{
  int buckets[ibf->hash_num];
 
  GNUNET_assert (ibf->hash_num <= ibf->size);
  ibf_get_indices (ibf, key, buckets);
  ibf_insert_into (ibf, key, buckets, 1);
}

References GNUNET_assert, InvertibleBloomFilter::hash_num, ibf_get_indices(), ibf_insert_into(), key, and InvertibleBloomFilter::size.

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ibf_remove()

void ibf_remove	(	struct InvertibleBloomFilter *	ibf,
		struct IBF_Key	key
	)

Remove a key from an IBF.

Parameters

ibf	the IBF
key	the element's hash code

Definition at line 190 of file ibf.c.

{
  int buckets[ibf->hash_num];
 
  GNUNET_assert (ibf->hash_num <= ibf->size);
  ibf_get_indices (ibf, key, buckets);
  ibf_insert_into (ibf, key, buckets, -1);
}

References GNUNET_assert, InvertibleBloomFilter::hash_num, ibf_get_indices(), ibf_insert_into(), key, and InvertibleBloomFilter::size.

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ibf_is_empty()

static int ibf_is_empty ( struct InvertibleBloomFilter *  ibf )

static

Test is the IBF is empty, i.e.

all counts, keys and key hashes are zero.

Definition at line 205 of file ibf.c.

{
  for (uint32_t i = 0; i < ibf->size; i++)
  {
    if (0 != ibf->count[i].count_val)
      return GNUNET_NO;
    if (0 != ibf->key_hash_sum[i].key_hash_val)
      return GNUNET_NO;
    if (0 != ibf->key_sum[i].key_val)
      return GNUNET_NO;
  }
  return GNUNET_YES;
}

References InvertibleBloomFilter::count, IBF_Count::count_val, GNUNET_NO, GNUNET_YES, InvertibleBloomFilter::key_hash_sum, IBF_KeyHash::key_hash_val, InvertibleBloomFilter::key_sum, IBF_Key::key_val, and InvertibleBloomFilter::size.

Referenced by ibf_decode().

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ibf_decode()

int ibf_decode	(	struct InvertibleBloomFilter *	ibf,
		int *	ret_side,
		struct IBF_Key *	ret_id
	)

Decode and remove an element from the IBF, if possible.

Parameters

ibf	the invertible bloom filter to decode
ret_side	sign of the cell's count where the decoded element came from. A negative sign indicates that the element was recovered resides in an IBF that was previously subtracted from.
ret_id	receives the hash code of the decoded element, if successful

Returns

GNUNET_YES if decoding an element was successful, GNUNET_NO if the IBF is empty, GNUNET_SYSERR if the decoding has failed

Parameters

ibf	the invertible bloom filter to decode
ret_side	sign of the cell's count where the decoded element came from. A negative sign indicates that the element was recovered resides in an IBF that was previously subtracted from.
ret_id	receives the hash code of the decoded element, if successful

Returns

GNUNET_YES if decoding an element was successful, GNUNET_NO if the IBF is empty, GNUNET_SYSERR if the decoding has failed

Definition at line 221 of file ibf.c.

{
  struct IBF_KeyHash hash;
  int buckets[ibf->hash_num];
 
  for (uint32_t i = 0; i < ibf->size; i++)
  {
    int hit;
 
    /* we can only decode from pure buckets */
    if ( (1 != ibf->count[i].count_val) &&
         (-1 != ibf->count[i].count_val) )
      continue;
 
    hash.key_hash_val = IBF_KEY_HASH_VAL (ibf->key_sum[i]);
 
    /* test if the hash matches the key */
    if (hash.key_hash_val != ibf->key_hash_sum[i].key_hash_val)
      continue;
 
    /* test if key in bucket hits its own location,
     * if not, the key hash was subject to collision */
    hit = GNUNET_NO;
    ibf_get_indices (ibf, ibf->key_sum[i], buckets);
    for (int j = 0; j < ibf->hash_num; j++)
      if (buckets[j] == i)
        hit = GNUNET_YES;
 
    if (GNUNET_NO == hit)
      continue;
 
    if (1 == ibf->count[i].count_val)
    {
      ibf->remote_decoded_count++;
    }
    else
    {
      ibf->local_decoded_count++;
    }
 
 
    if (NULL != ret_side)
      *ret_side = ibf->count[i].count_val;
    if (NULL != ret_id)
      *ret_id = ibf->key_sum[i];
 
    /* insert on the opposite side, effectively removing the element */
    ibf_insert_into (ibf, ibf->key_sum[i], buckets, -ibf->count[i].count_val);
 
    return GNUNET_YES;
  }
 
  if (GNUNET_YES == ibf_is_empty (ibf))
    return GNUNET_NO;
  return GNUNET_SYSERR;
}

References InvertibleBloomFilter::count, IBF_Count::count_val, GNUNET_NO, GNUNET_SYSERR, GNUNET_YES, InvertibleBloomFilter::hash_num, ibf_get_indices(), ibf_insert_into(), ibf_is_empty(), IBF_KEY_HASH_VAL, InvertibleBloomFilter::key_hash_sum, IBF_KeyHash::key_hash_val, InvertibleBloomFilter::key_sum, InvertibleBloomFilter::local_decoded_count, InvertibleBloomFilter::remote_decoded_count, and InvertibleBloomFilter::size.

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ibf_get_max_counter()

uint8_t ibf_get_max_counter

(

struct InvertibleBloomFilter *

ibf

)

Returns the minimal bytes needed to store the counter of the IBF.

Parameters

ibf

the IBF

Definition at line 287 of file ibf.c.

{
  long long max_counter = 0;
  for (uint64_t i = 0; i < ibf->size; i++)
  {
    if (ibf->count[i].count_val > max_counter)
    {
      max_counter = ibf->count[i].count_val;
    }
  }
  return 64 - __builtin_clzll (max_counter);
}

References InvertibleBloomFilter::count, IBF_Count::count_val, and InvertibleBloomFilter::size.

Referenced by send_ibf().

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ibf_write_slice()

void ibf_write_slice	(	const struct InvertibleBloomFilter *	ibf,
		uint32_t	start,
		uint64_t	count,
		void *	buf,
		uint8_t	counter_max_length
	)

Write buckets from an ibf to a buffer.

Exactly (IBF_BUCKET_SIZE*ibf->size) bytes are written to buf.

Parameters

ibf	the ibf to write
start	with which bucket to start
count	how many buckets to write
buf	buffer to write the data to
max	bit length of a counter for unpacking

Definition at line 312 of file ibf.c.

{
  struct IBF_Key *key_dst;
  struct IBF_KeyHash *key_hash_dst;
 
  GNUNET_assert (start + count <= ibf->size);
 
  /* copy keys */
  key_dst = (struct IBF_Key *) buf;
  GNUNET_memcpy (key_dst,
                 ibf->key_sum + start,
                 count * sizeof(*key_dst));
  key_dst += count;
  /* copy key hashes */
  key_hash_dst = (struct IBF_KeyHash *) key_dst;
  GNUNET_memcpy (key_hash_dst,
                 ibf->key_hash_sum + start,
                 count * sizeof(*key_hash_dst));
  key_hash_dst += count;
 
  /* pack and copy counter */
  pack_counter (ibf,
                start,
                count,
                (uint8_t *) key_hash_dst,
                counter_max_length);
 
 
}

References GNUNET_assert, GNUNET_memcpy, InvertibleBloomFilter::key_hash_sum, InvertibleBloomFilter::key_sum, pack_counter(), size, and start.

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pack_counter()

void pack_counter	(	const struct InvertibleBloomFilter *	ibf,
		uint32_t	start,
		uint64_t	count,
		uint8_t *	buf,
		uint8_t	counter_max_length
	)

Packs the counter to transmit only the smallest possible amount of bytes and preventing overflow of the counter.

Parameters

ibf	the ibf to write
start	with which bucket to start
count	how many buckets to write
buf	buffer to write the data to
max	bit length of a counter for unpacking

Iterate over IBF bucket

Pack and compose counters to byte values

Shift bits if more than a byte has to be written or the store size is not empty

Pack data left in story before finishing

Definition at line 348 of file ibf.c.

{
  uint8_t store_size = 0;
  uint8_t store = 0;
  uint16_t byte_ctr = 0;
 
  for (uint64_t i = start; i< (count + start);)
  {
    uint64_t count_val_to_write = ibf->count[i].count_val;
    uint8_t count_len_to_write = counter_max_length;
 
    while ((count_len_to_write + store_size) >= 8)
    {
      uint8_t bit_shift = 0;
 
      if ((store_size > 0) || (count_len_to_write > 8))
      {
        uint8_t bit_unused = 8 - store_size;
        bit_shift = count_len_to_write - bit_unused;
        store = store << bit_unused;
      }
 
      buf[byte_ctr] = ((count_val_to_write >> bit_shift) | store) & 0xFF;
      byte_ctr++;
      count_len_to_write -= (8 - store_size);
      count_val_to_write = count_val_to_write & ((1ULL <<
                                                  count_len_to_write) - 1);
      store = 0;
      store_size = 0;
    }
    store = (store << count_len_to_write) | count_val_to_write;
    store_size = store_size + count_len_to_write;
    count_len_to_write = 0;
    i++;
  }
 
  if (store_size > 0)
  {
    buf[byte_ctr] = store << (8 - store_size);
    byte_ctr++;
  }
 
}

References InvertibleBloomFilter::count, IBF_Count::count_val, and start.

Referenced by ibf_write_slice().

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unpack_counter()

void unpack_counter	(	const struct InvertibleBloomFilter *	ibf,
		uint32_t	start,
		uint64_t	count,
		uint8_t *	buf,
		uint8_t	counter_max_length
	)

Unpacks the counter to transmit only the smallest possible amount of bytes and preventing overflow of the counter.

Parameters

ibf	the ibf to write
start	with which bucket to start
count	how many buckets to write
buf	buffer to write the data to
max	bit length of a counter for unpacking

Iterate over received bytes

Pack data left in story before finishing

Stop decoding when end is reached

Definition at line 411 of file ibf.c.

{
  uint64_t ibf_counter_ctr = 0;
  uint64_t store = 0;
  uint64_t store_bit_ctr = 0;
  uint64_t byte_ctr = 0;
 
  while (true)
  {
    uint8_t byte_read = buf[byte_ctr];
    uint8_t bit_to_read_left = 8;
    byte_ctr++;
 
    while (true)
    {
      if (ibf_counter_ctr > (count - 1))
        return;
 
      /*
       * Unpack the counter
       */
      if ((store_bit_ctr + bit_to_read_left) >= counter_max_length)
      {
        uint8_t bytes_used = counter_max_length - store_bit_ctr;
        if (store_bit_ctr > 0)
        {
          store = store << bytes_used;
        }
        {
          uint8_t bytes_to_shift = bit_to_read_left - bytes_used;
          uint64_t counter_part = byte_read >> bytes_to_shift;
          store = store | counter_part;
          ibf->count[ibf_counter_ctr + start].count_val = store;
          byte_read = byte_read & ((1 << bytes_to_shift) - 1);
          bit_to_read_left -= bytes_used;
          ibf_counter_ctr++;
          store = 0;
          store_bit_ctr = 0;
        }
      }
      else
      {
        store_bit_ctr += bit_to_read_left;
        if (0 == store)
        {
          store = byte_read;
        }
        else
        {
          store = store << bit_to_read_left;
          store = store | byte_read;
        }
        break;
      }
    }
  }
}

References InvertibleBloomFilter::count, IBF_Count::count_val, and start.

Referenced by ibf_read_slice().

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ibf_read_slice()

void ibf_read_slice	(	const void *	buf,
		uint32_t	start,
		uint64_t	count,
		struct InvertibleBloomFilter *	ibf,
		uint8_t	counter_max_length
	)

Read buckets from a buffer into an ibf.

Parameters

buf	pointer to the buffer to read from
start	which bucket to start at
count	how many buckets to read
ibf	the ibf to read from
max	bit length of a counter for unpacking

Definition at line 493 of file ibf.c.

{
  struct IBF_Key *key_src;
  struct IBF_KeyHash *key_hash_src;
  struct IBF_Count *count_src;
 
  GNUNET_assert (count > 0);
  GNUNET_assert (start + count <= ibf->size);
 
  /* copy keys */
  key_src = (struct IBF_Key *) buf;
  GNUNET_memcpy (ibf->key_sum + start,
                 key_src,
                 count * sizeof *key_src);
  key_src += count;
  /* copy key hashes */
  key_hash_src = (struct IBF_KeyHash *) key_src;
  GNUNET_memcpy (ibf->key_hash_sum + start,
                 key_hash_src,
                 count * sizeof *key_hash_src);
  key_hash_src += count;
 
  /* copy and unpack counts  */
  count_src = (struct IBF_Count *) key_hash_src;
  unpack_counter (ibf,start,count,(uint8_t *) count_src,counter_max_length);
}

References GNUNET_assert, GNUNET_memcpy, InvertibleBloomFilter::key_hash_sum, InvertibleBloomFilter::key_sum, size, start, and unpack_counter().

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ibf_subtract()

void ibf_subtract	(	struct InvertibleBloomFilter *	ibf1,
		const struct InvertibleBloomFilter *	ibf2
	)

Subtract ibf2 from ibf1, storing the result in ibf1.

The two IBF's must have the same parameters size and hash_num.

Parameters

ibf1	IBF that is subtracted from
ibf2	IBF that will be subtracted from ibf1

Definition at line 533 of file ibf.c.

{
  GNUNET_assert (ibf1->size == ibf2->size);
  GNUNET_assert (ibf1->hash_num == ibf2->hash_num);
 
  for (uint32_t i = 0; i < ibf1->size; i++)
  {
    ibf1->count[i].count_val -= ibf2->count[i].count_val;
    ibf1->key_hash_sum[i].key_hash_val ^= ibf2->key_hash_sum[i].key_hash_val;
    ibf1->key_sum[i].key_val ^= ibf2->key_sum[i].key_val;
  }
}

References InvertibleBloomFilter::count, IBF_Count::count_val, GNUNET_assert, InvertibleBloomFilter::hash_num, InvertibleBloomFilter::key_hash_sum, IBF_KeyHash::key_hash_val, InvertibleBloomFilter::key_sum, IBF_Key::key_val, and InvertibleBloomFilter::size.

ibf_dup()

struct InvertibleBloomFilter * ibf_dup

(

const struct InvertibleBloomFilter *

ibf

)

Create a copy of an IBF, the copy has to be destroyed properly.

Parameters

ibf	the IBF to copy

Definition at line 554 of file ibf.c.

{
  struct InvertibleBloomFilter *copy;
 
  copy = GNUNET_malloc (sizeof *copy);
  copy->hash_num = ibf->hash_num;
  copy->size = ibf->size;
  copy->key_hash_sum = GNUNET_memdup (ibf->key_hash_sum,
                                      ibf->size * sizeof(struct IBF_KeyHash));
  copy->key_sum = GNUNET_memdup (ibf->key_sum,
                                 ibf->size * sizeof(struct IBF_Key));
  copy->count = GNUNET_memdup (ibf->count,
                               ibf->size * sizeof(struct IBF_Count));
  return copy;
}

References InvertibleBloomFilter::count, GNUNET_malloc, GNUNET_memdup, InvertibleBloomFilter::hash_num, InvertibleBloomFilter::key_hash_sum, InvertibleBloomFilter::key_sum, and InvertibleBloomFilter::size.

ibf_destroy()

void ibf_destroy

(

struct InvertibleBloomFilter *

ibf

)

Destroy all resources associated with the invertible bloom filter.

No more ibf_*-functions may be called on ibf after calling destroy.

Parameters

ibf	the intertible bloom filter to destroy

Definition at line 578 of file ibf.c.

{
  GNUNET_free (ibf->key_sum);
  GNUNET_free (ibf->key_hash_sum);
  GNUNET_free (ibf->count);
  GNUNET_free (ibf);
}

References InvertibleBloomFilter::count, GNUNET_free, InvertibleBloomFilter::key_hash_sum, and InvertibleBloomFilter::key_sum.