container_multihashmap.c

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/*
     This file is part of GNUnet.
     Copyright (C) 2008, 2012 GNUnet e.V.

     GNUnet is free software: you can redistribute it and/or modify it
     under the terms of the GNU Affero General Public License as published
     by the Free Software Foundation, either version 3 of the License,
     or (at your option) any later version.

     GNUnet 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
     Affero General Public License for more details.

     You should have received a copy of the GNU Affero General Public License
     along with this program.  If not, see <http://www.gnu.org/licenses/>.

     SPDX-License-Identifier: AGPL3.0-or-later
 */
#include "platform.h"
#include "gnunet_container_lib.h"

#define LOG(kind, ...) \
  GNUNET_log_from(kind, "util-container-multihashmap", __VA_ARGS__)

#define NEXT_CACHE_SIZE 16


struct BigMapEntry {
  void *value;

  struct BigMapEntry *next;

  struct GNUNET_HashCode key;
};


struct SmallMapEntry {
  void *value;

  struct SmallMapEntry *next;

  const struct GNUNET_HashCode *key;
};


union MapEntry {
  struct SmallMapEntry *sme;

  struct BigMapEntry *bme;
};


struct GNUNET_CONTAINER_MultiHashMap {
  union MapEntry *map;

  unsigned int size;

  unsigned int map_length;

  int use_small_entries;

  unsigned int modification_counter;

  union MapEntry next_cache[NEXT_CACHE_SIZE];

  unsigned int next_cache_off;
};


struct GNUNET_CONTAINER_MultiHashMapIterator {
  union MapEntry me;

  unsigned int idx;

  unsigned int modification_counter;

  const struct GNUNET_CONTAINER_MultiHashMap *map;
};


struct GNUNET_CONTAINER_MultiHashMap *
GNUNET_CONTAINER_multihashmap_create(unsigned int len, int do_not_copy_keys)
{
  struct GNUNET_CONTAINER_MultiHashMap *hm;

  GNUNET_assert(len > 0);
  hm = GNUNET_new(struct GNUNET_CONTAINER_MultiHashMap);
  if (len * sizeof(union MapEntry) > GNUNET_MAX_MALLOC_CHECKED)
    {
      size_t s;
      /* application *explicitly* requested very large map, hopefully
         it checks the return value... */
      s = len * sizeof(union MapEntry);
      if ((s / sizeof(union MapEntry)) != len)
        return NULL; /* integer overflow on multiplication */
      if (NULL == (hm->map = GNUNET_malloc_large(s)))
        {
          /* out of memory */
          GNUNET_log(GNUNET_ERROR_TYPE_WARNING,
                     "Out of memory allocating large hash map (%u entries)\n",
                     len);
          GNUNET_free(hm);
          return NULL;
        }
    }
  else
    {
      hm->map = GNUNET_new_array(len, union MapEntry);
    }
  hm->map_length = len;
  hm->use_small_entries = do_not_copy_keys;
  return hm;
}


void
GNUNET_CONTAINER_multihashmap_destroy(
  struct GNUNET_CONTAINER_MultiHashMap *map)
{
  GNUNET_assert(0 == map->next_cache_off);
  for (unsigned int i = 0; i < map->map_length; i++)
    {
      union MapEntry me;

      me = map->map[i];
      if (map->use_small_entries)
        {
          struct SmallMapEntry *sme;
          struct SmallMapEntry *nxt;

          nxt = me.sme;
          while (NULL != (sme = nxt))
            {
              nxt = sme->next;
              GNUNET_free(sme);
            }
          me.sme = NULL;
        }
      else
        {
          struct BigMapEntry *bme;
          struct BigMapEntry *nxt;

          nxt = me.bme;
          while (NULL != (bme = nxt))
            {
              nxt = bme->next;
              GNUNET_free(bme);
            }
          me.bme = NULL;
        }
    }
  GNUNET_free(map->map);
  GNUNET_free(map);
}


static unsigned int
idx_of(const struct GNUNET_CONTAINER_MultiHashMap *map,
       const struct GNUNET_HashCode *key)
{
  GNUNET_assert(map != NULL);
  return (*(unsigned int *)key) % map->map_length;
}


unsigned int
GNUNET_CONTAINER_multihashmap_size(
  const struct GNUNET_CONTAINER_MultiHashMap *map)
{
  return map->size;
}


void *
GNUNET_CONTAINER_multihashmap_get(
  const struct GNUNET_CONTAINER_MultiHashMap *map,
  const struct GNUNET_HashCode *key)
{
  union MapEntry me;

  me = map->map[idx_of(map, key)];
  if (map->use_small_entries)
    {
      struct SmallMapEntry *sme;

      for (sme = me.sme; NULL != sme; sme = sme->next)
        if (0 == GNUNET_memcmp(key, sme->key))
          return sme->value;
    }
  else
    {
      struct BigMapEntry *bme;

      for (bme = me.bme; NULL != bme; bme = bme->next)
        if (0 == GNUNET_memcmp(key, &bme->key))
          return bme->value;
    }
  return NULL;
}


int
GNUNET_CONTAINER_multihashmap_iterate(
  struct GNUNET_CONTAINER_MultiHashMap *map,
  GNUNET_CONTAINER_MulitHashMapIteratorCallback it,
  void *it_cls)
{
  int count;
  union MapEntry me;
  union MapEntry *ce;
  struct GNUNET_HashCode kc;

  GNUNET_assert(NULL != map);
  ce = &map->next_cache[map->next_cache_off];
  GNUNET_assert(++map->next_cache_off < NEXT_CACHE_SIZE);
  count = 0;
  for (unsigned i = 0; i < map->map_length; i++)
    {
      me = map->map[i];
      if (map->use_small_entries)
        {
          struct SmallMapEntry *sme;

          ce->sme = me.sme;
          while (NULL != (sme = ce->sme))
            {
              ce->sme = sme->next;
              if (NULL != it)
                {
                  if (GNUNET_OK != it(it_cls, sme->key, sme->value))
                    {
                      GNUNET_assert(--map->next_cache_off < NEXT_CACHE_SIZE);
                      return GNUNET_SYSERR;
                    }
                }
              count++;
            }
        }
      else
        {
          struct BigMapEntry *bme;

          ce->bme = me.bme;
          while (NULL != (bme = ce->bme))
            {
              ce->bme = bme->next;
              if (NULL != it)
                {
                  kc = bme->key;
                  if (GNUNET_OK != it(it_cls, &kc, bme->value))
                    {
                      GNUNET_assert(--map->next_cache_off < NEXT_CACHE_SIZE);
                      return GNUNET_SYSERR;
                    }
                }
              count++;
            }
        }
    }
  GNUNET_assert(--map->next_cache_off < NEXT_CACHE_SIZE);
  return count;
}


static void
update_next_cache_bme(struct GNUNET_CONTAINER_MultiHashMap *map,
                      const struct BigMapEntry *bme)
{
  for (unsigned int i = 0; i < map->next_cache_off; i++)
    if (map->next_cache[i].bme == bme)
      map->next_cache[i].bme = bme->next;
}


static void
update_next_cache_sme(struct GNUNET_CONTAINER_MultiHashMap *map,
                      const struct SmallMapEntry *sme)
{
  for (unsigned int i = 0; i < map->next_cache_off; i++)
    if (map->next_cache[i].sme == sme)
      map->next_cache[i].sme = sme->next;
}


int
GNUNET_CONTAINER_multihashmap_remove(struct GNUNET_CONTAINER_MultiHashMap *map,
                                     const struct GNUNET_HashCode *key,
                                     const void *value)
{
  union MapEntry me;
  unsigned int i;

  map->modification_counter++;

  i = idx_of(map, key);
  me = map->map[i];
  if (map->use_small_entries)
    {
      struct SmallMapEntry *p;

      p = NULL;
      for (struct SmallMapEntry *sme = me.sme; NULL != sme; sme = sme->next)
        {
          if ((0 == GNUNET_memcmp(key, sme->key)) && (value == sme->value))
            {
              if (NULL == p)
                map->map[i].sme = sme->next;
              else
                p->next = sme->next;
              update_next_cache_sme(map, sme);
              GNUNET_free(sme);
              map->size--;
              return GNUNET_YES;
            }
          p = sme;
        }
    }
  else
    {
      struct BigMapEntry *p;

      p = NULL;
      for (struct BigMapEntry *bme = me.bme; NULL != bme; bme = bme->next)
        {
          if ((0 == GNUNET_memcmp(key, &bme->key)) && (value == bme->value))
            {
              if (NULL == p)
                map->map[i].bme = bme->next;
              else
                p->next = bme->next;
              update_next_cache_bme(map, bme);
              GNUNET_free(bme);
              map->size--;
              return GNUNET_YES;
            }
          p = bme;
        }
    }
  return GNUNET_NO;
}


int
GNUNET_CONTAINER_multihashmap_remove_all(
  struct GNUNET_CONTAINER_MultiHashMap *map,
  const struct GNUNET_HashCode *key)
{
  union MapEntry me;
  unsigned int i;
  int ret;

  map->modification_counter++;

  ret = 0;
  i = idx_of(map, key);
  me = map->map[i];
  if (map->use_small_entries)
    {
      struct SmallMapEntry *sme;
      struct SmallMapEntry *p;

      p = NULL;
      sme = me.sme;
      while (NULL != sme)
        {
          if (0 == GNUNET_memcmp(key, sme->key))
            {
              if (NULL == p)
                map->map[i].sme = sme->next;
              else
                p->next = sme->next;
              update_next_cache_sme(map, sme);
              GNUNET_free(sme);
              map->size--;
              if (NULL == p)
                sme = map->map[i].sme;
              else
                sme = p->next;
              ret++;
            }
          else
            {
              p = sme;
              sme = sme->next;
            }
        }
    }
  else
    {
      struct BigMapEntry *bme;
      struct BigMapEntry *p;

      p = NULL;
      bme = me.bme;
      while (NULL != bme)
        {
          if (0 == GNUNET_memcmp(key, &bme->key))
            {
              if (NULL == p)
                map->map[i].bme = bme->next;
              else
                p->next = bme->next;
              update_next_cache_bme(map, bme);
              GNUNET_free(bme);
              map->size--;
              if (NULL == p)
                bme = map->map[i].bme;
              else
                bme = p->next;
              ret++;
            }
          else
            {
              p = bme;
              bme = bme->next;
            }
        }
    }
  return ret;
}


static int
remove_all(void *cls, const struct GNUNET_HashCode *key, void *value)
{
  struct GNUNET_CONTAINER_MultiHashMap *map = cls;

  GNUNET_assert(GNUNET_YES ==
                GNUNET_CONTAINER_multihashmap_remove(map, key, value));
  return GNUNET_OK;
}


unsigned int
GNUNET_CONTAINER_multihashmap_clear(struct GNUNET_CONTAINER_MultiHashMap *map)
{
  unsigned int ret;

  ret = map->size;
  GNUNET_CONTAINER_multihashmap_iterate(map, &remove_all, map);
  return ret;
}


int
GNUNET_CONTAINER_multihashmap_contains(
  const struct GNUNET_CONTAINER_MultiHashMap *map,
  const struct GNUNET_HashCode *key)
{
  union MapEntry me;

  me = map->map[idx_of(map, key)];
  if (map->use_small_entries)
    {
      struct SmallMapEntry *sme;

      for (sme = me.sme; NULL != sme; sme = sme->next)
        if (0 == GNUNET_memcmp(key, sme->key))
          return GNUNET_YES;
    }
  else
    {
      struct BigMapEntry *bme;

      for (bme = me.bme; NULL != bme; bme = bme->next)
        if (0 == GNUNET_memcmp(key, &bme->key))
          return GNUNET_YES;
    }
  return GNUNET_NO;
}


int
GNUNET_CONTAINER_multihashmap_contains_value(
  const struct GNUNET_CONTAINER_MultiHashMap *map,
  const struct GNUNET_HashCode *key,
  const void *value)
{
  union MapEntry me;

  me = map->map[idx_of(map, key)];
  if (map->use_small_entries)
    {
      struct SmallMapEntry *sme;

      for (sme = me.sme; NULL != sme; sme = sme->next)
        if ((0 == GNUNET_memcmp(key, sme->key)) && (sme->value == value))
          return GNUNET_YES;
    }
  else
    {
      struct BigMapEntry *bme;

      for (bme = me.bme; NULL != bme; bme = bme->next)
        if ((0 == GNUNET_memcmp(key, &bme->key)) && (bme->value == value))
          return GNUNET_YES;
    }
  return GNUNET_NO;
}


static void
grow(struct GNUNET_CONTAINER_MultiHashMap *map)
{
  union MapEntry *old_map;
  union MapEntry *new_map;
  unsigned int old_len;
  unsigned int new_len;
  unsigned int idx;

  old_map = map->map;
  old_len = map->map_length;
  GNUNET_assert(0 != old_len);
  new_len = old_len * 2;
  if (0 == new_len) /* 2^31 * 2 == 0 */
    new_len = old_len; /* never use 0 */
  if (new_len == old_len)
    return; /* nothing changed */
  new_map = GNUNET_malloc_large(new_len * sizeof(union MapEntry));
  if (NULL == new_map)
    return; /* grow not possible */
  map->modification_counter++;
  map->map_length = new_len;
  map->map = new_map;
  for (unsigned int i = 0; i < old_len; i++)
    {
      if (map->use_small_entries)
        {
          struct SmallMapEntry *sme;

          while (NULL != (sme = old_map[i].sme))
            {
              old_map[i].sme = sme->next;
              idx = idx_of(map, sme->key);
              sme->next = new_map[idx].sme;
              new_map[idx].sme = sme;
            }
        }
      else
        {
          struct BigMapEntry *bme;

          while (NULL != (bme = old_map[i].bme))
            {
              old_map[i].bme = bme->next;
              idx = idx_of(map, &bme->key);
              bme->next = new_map[idx].bme;
              new_map[idx].bme = bme;
            }
        }
    }
  GNUNET_free(old_map);
}


int
GNUNET_CONTAINER_multihashmap_put(struct GNUNET_CONTAINER_MultiHashMap *map,
                                  const struct GNUNET_HashCode *key,
                                  void *value,
                                  enum GNUNET_CONTAINER_MultiHashMapOption opt)
{
  union MapEntry me;
  unsigned int i;

  i = idx_of(map, key);
  if ((opt != GNUNET_CONTAINER_MULTIHASHMAPOPTION_MULTIPLE) &&
      (opt != GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_FAST))
    {
      me = map->map[i];
      if (map->use_small_entries)
        {
          struct SmallMapEntry *sme;

          for (sme = me.sme; NULL != sme; sme = sme->next)
            if (0 == GNUNET_memcmp(key, sme->key))
              {
                if (opt == GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY)
                  return GNUNET_SYSERR;
                sme->value = value;
                return GNUNET_NO;
              }
        }
      else
        {
          struct BigMapEntry *bme;

          for (bme = me.bme; NULL != bme; bme = bme->next)
            if (0 == GNUNET_memcmp(key, &bme->key))
              {
                if (opt == GNUNET_CONTAINER_MULTIHASHMAPOPTION_UNIQUE_ONLY)
                  return GNUNET_SYSERR;
                bme->value = value;
                return GNUNET_NO;
              }
        }
    }
  if (map->size / 3 >= map->map_length / 4)
    {
      grow(map);
      i = idx_of(map, key);
    }
  if (map->use_small_entries)
    {
      struct SmallMapEntry *sme;

      sme = GNUNET_new(struct SmallMapEntry);
      sme->key = key;
      sme->value = value;
      sme->next = map->map[i].sme;
      map->map[i].sme = sme;
    }
  else
    {
      struct BigMapEntry *bme;

      bme = GNUNET_new(struct BigMapEntry);
      bme->key = *key;
      bme->value = value;
      bme->next = map->map[i].bme;
      map->map[i].bme = bme;
    }
  map->size++;
  return GNUNET_OK;
}


int
GNUNET_CONTAINER_multihashmap_get_multiple(
  struct GNUNET_CONTAINER_MultiHashMap *map,
  const struct GNUNET_HashCode *key,
  GNUNET_CONTAINER_MulitHashMapIteratorCallback it,
  void *it_cls)
{
  int count;
  union MapEntry *me;
  union MapEntry *ce;

  ce = &map->next_cache[map->next_cache_off];
  GNUNET_assert(++map->next_cache_off < NEXT_CACHE_SIZE);
  count = 0;
  me = &map->map[idx_of(map, key)];
  if (map->use_small_entries)
    {
      struct SmallMapEntry *sme;

      ce->sme = me->sme;
      while (NULL != (sme = ce->sme))
        {
          ce->sme = sme->next;
          if (0 != GNUNET_memcmp(key, sme->key))
            continue;
          if ((NULL != it) && (GNUNET_OK != it(it_cls, key, sme->value)))
            {
              GNUNET_assert(--map->next_cache_off < NEXT_CACHE_SIZE);
              return GNUNET_SYSERR;
            }
          count++;
        }
    }
  else
    {
      struct BigMapEntry *bme;

      ce->bme = me->bme;
      while (NULL != (bme = ce->bme))
        {
          ce->bme = bme->next;
          if (0 != GNUNET_memcmp(key, &bme->key))
            continue;
          if ((NULL != it) && (GNUNET_OK != it(it_cls, key, bme->value)))
            {
              GNUNET_assert(--map->next_cache_off < NEXT_CACHE_SIZE);
              return GNUNET_SYSERR;
            }
          count++;
        }
    }
  GNUNET_assert(--map->next_cache_off < NEXT_CACHE_SIZE);
  return count;
}


unsigned int
GNUNET_CONTAINER_multihashmap_get_random(
  const struct GNUNET_CONTAINER_MultiHashMap *map,
  GNUNET_CONTAINER_MulitHashMapIteratorCallback it,
  void *it_cls)
{
  unsigned int off;
  unsigned int idx;
  union MapEntry me;

  if (0 == map->size)
    return 0;
  if (NULL == it)
    return 1;
  off = GNUNET_CRYPTO_random_u32(GNUNET_CRYPTO_QUALITY_NONCE, map->size);
  for (idx = 0; idx < map->map_length; idx++)
    {
      me = map->map[idx];
      if (map->use_small_entries)
        {
          struct SmallMapEntry *sme;
          struct SmallMapEntry *nxt;

          nxt = me.sme;
          while (NULL != (sme = nxt))
            {
              nxt = sme->next;
              if (0 == off)
                {
                  if (GNUNET_OK != it(it_cls, sme->key, sme->value))
                    return GNUNET_SYSERR;
                  return 1;
                }
              off--;
            }
        }
      else
        {
          struct BigMapEntry *bme;
          struct BigMapEntry *nxt;

          nxt = me.bme;
          while (NULL != (bme = nxt))
            {
              nxt = bme->next;
              if (0 == off)
                {
                  if (GNUNET_OK != it(it_cls, &bme->key, bme->value))
                    return GNUNET_SYSERR;
                  return 1;
                }
              off--;
            }
        }
    }
  GNUNET_break(0);
  return GNUNET_SYSERR;
}


struct GNUNET_CONTAINER_MultiHashMapIterator *
GNUNET_CONTAINER_multihashmap_iterator_create(
  const struct GNUNET_CONTAINER_MultiHashMap *map)
{
  struct GNUNET_CONTAINER_MultiHashMapIterator *iter;

  iter = GNUNET_new(struct GNUNET_CONTAINER_MultiHashMapIterator);
  iter->map = map;
  iter->modification_counter = map->modification_counter;
  iter->me = map->map[0];
  return iter;
}


int
GNUNET_CONTAINER_multihashmap_iterator_next(
  struct GNUNET_CONTAINER_MultiHashMapIterator *iter,
  struct GNUNET_HashCode *key,
  const void **value)
{
  /* make sure the map has not been modified */
  GNUNET_assert(iter->modification_counter == iter->map->modification_counter);

  /* look for the next entry, skipping empty buckets */
  while (1)
    {
      if (iter->idx >= iter->map->map_length)
        return GNUNET_NO;
      if (GNUNET_YES == iter->map->use_small_entries)
        {
          if (NULL != iter->me.sme)
            {
              if (NULL != key)
                *key = *iter->me.sme->key;
              if (NULL != value)
                *value = iter->me.sme->value;
              iter->me.sme = iter->me.sme->next;
              return GNUNET_YES;
            }
        }
      else
        {
          if (NULL != iter->me.bme)
            {
              if (NULL != key)
                *key = iter->me.bme->key;
              if (NULL != value)
                *value = iter->me.bme->value;
              iter->me.bme = iter->me.bme->next;
              return GNUNET_YES;
            }
        }
      iter->idx += 1;
      if (iter->idx < iter->map->map_length)
        iter->me = iter->map->map[iter->idx];
    }
}


void
GNUNET_CONTAINER_multihashmap_iterator_destroy(
  struct GNUNET_CONTAINER_MultiHashMapIterator *iter)
{
  GNUNET_free(iter);
}


/* end of container_multihashmap.c */