/**

 * WinPR: Windows Portable Runtime

 * System.Collections.Hashtable

 *

 * Copyright 2014 Marc-Andre Moreau <marcandre.moreau@gmail.com>

 *

 * 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 <winpr/config.h>

#include <winpr/crt.h>

#include <winpr/assert.h>

#include <winpr/collections.h>

/**

 * This implementation is based on the public domain

 * hash table implementation made by Keith Pomakis:

 *

 * http://www.pomakis.com/hashtable/hashtable.c

 * http://www.pomakis.com/hashtable/hashtable.h

 */

typedef struct s_wKeyValuePair wKeyValuePair;

struct s_wKeyValuePair

{

  void* key;

  void* value;

  wKeyValuePair* next;

  BOOL markedForRemove;

};

struct s_wHashTable

{

  BOOL synchronized;

  CRITICAL_SECTION lock;

  size_t numOfBuckets;

  size_t numOfElements;

  float idealRatio;

  float lowerRehashThreshold;

  float upperRehashThreshold;

  wKeyValuePair** bucketArray;

  HASH_TABLE_HASH_FN hash;

  wObject key;

  wObject value;

  DWORD foreachRecursionLevel;

  DWORD pendingRemoves;

};

BOOL HashTable_PointerCompare(const void* pointer1, const void* pointer2)

{

  return (pointer1 == pointer2);

}

UINT32 HashTable_PointerHash(const void* pointer)

{

  return ((UINT32)(UINT_PTR)pointer) >> 4;

}

BOOL HashTable_StringCompare(const void* string1, const void* string2)

{

  if (!string1 || !string2)

    return (string1 == string2);

  return (strcmp((const char*)string1, (const char*)string2) == 0);

}

UINT32 HashTable_StringHash(const void* key)

{

  UINT32 c = 0;

  UINT32 hash = 5381;

  const BYTE* str = (const BYTE*)key;

  /* djb2 algorithm */

  while ((c = *str++) != '\0')

    hash = (hash * 33) + c;

  return hash;

}

void* HashTable_StringClone(const void* str)

{

  return winpr_ObjectStringClone(str);

}

void HashTable_StringFree(void* str)

{

  winpr_ObjectStringFree(str);

}

WINPR_ATTR_NODISCARD

static inline BOOL HashTable_IsProbablePrime(size_t oddNumber)

{

  for (size_t i = 3; i < 51; i += 2)

  {

    if (oddNumber == i)

      return TRUE;

    else if (oddNumber % i == 0)

      return FALSE;

  }

  return TRUE; /* maybe */

}

WINPR_ATTR_NODISCARD

static inline size_t HashTable_CalculateIdealNumOfBuckets(wHashTable* table)

{

  WINPR_ASSERT(table);

  const float numOfElements = (float)table->numOfElements;

  const float tmp = (numOfElements / table->idealRatio);

  size_t idealNumOfBuckets = (size_t)tmp;

  if (idealNumOfBuckets < 5)

    idealNumOfBuckets = 5;

  else

    idealNumOfBuckets |= 0x01;

  while (!HashTable_IsProbablePrime(idealNumOfBuckets))

    idealNumOfBuckets += 2;

  return idealNumOfBuckets;

}

static inline void HashTable_Rehash(wHashTable* table, size_t numOfBuckets)

{

  UINT32 hashValue = 0;

  wKeyValuePair* nextPair = nullptr;

  wKeyValuePair** newBucketArray = nullptr;

  WINPR_ASSERT(table);

  if (numOfBuckets == 0)

    numOfBuckets = HashTable_CalculateIdealNumOfBuckets(table);

  if (numOfBuckets == table->numOfBuckets)

    return; /* already the right size! */

  newBucketArray = (wKeyValuePair**)calloc(numOfBuckets, sizeof(wKeyValuePair*));

  if (!newBucketArray)

  {

    /*

     * Couldn't allocate memory for the new array.

     * This isn't a fatal error; we just can't perform the rehash.

     */

    return;

  }

  for (size_t index = 0; index < table->numOfBuckets; index++)

  {

    wKeyValuePair* pair = table->bucketArray[index];

    while (pair)

    {

      nextPair = pair->next;

      hashValue = table->hash(pair->key) % numOfBuckets;

      pair->next = newBucketArray[hashValue];

      newBucketArray[hashValue] = pair;

      pair = nextPair;

    }

  }

  free((void*)table->bucketArray);

  table->bucketArray = newBucketArray;

  table->numOfBuckets = numOfBuckets;

}

WINPR_ATTR_NODISCARD

static inline BOOL HashTable_Equals(wHashTable* table, const wKeyValuePair* pair, const void* key)

{

  WINPR_ASSERT(table);

  WINPR_ASSERT(pair);

  WINPR_ASSERT(key);

  return table->key.fnObjectEquals(key, pair->key);

}

WINPR_ATTR_NODISCARD

static inline wKeyValuePair* HashTable_Get(wHashTable* table, const void* key)

{

  UINT32 hashValue = 0;

  wKeyValuePair* pair = nullptr;

  WINPR_ASSERT(table);

  if (!key)

    return nullptr;

  hashValue = table->hash(key) % table->numOfBuckets;

  pair = table->bucketArray[hashValue];

  while (pair && !HashTable_Equals(table, pair, key))

    pair = pair->next;

  return pair;

}

static inline void disposeKey(wHashTable* table, void* key)

{

  WINPR_ASSERT(table);

  if (table->key.fnObjectFree)

    table->key.fnObjectFree(key);

}

static inline void disposeValue(wHashTable* table, void* value)

{

  WINPR_ASSERT(table);

  if (table->value.fnObjectFree)

    table->value.fnObjectFree(value);

}

static inline void disposePair(wHashTable* table, wKeyValuePair* pair)

{

  WINPR_ASSERT(table);

  if (!pair)

    return;

  disposeKey(table, pair->key);

  disposeValue(table, pair->value);

  free(pair);

}

static inline void setKey(wHashTable* table, wKeyValuePair* pair, const void* key)

{

  WINPR_ASSERT(table);

  if (!pair)

    return;

  disposeKey(table, pair->key);

  if (table->key.fnObjectNew)

    pair->key = table->key.fnObjectNew(key);

  else

  {

    union

    {

      const void* cpv;

      void* pv;

    } cnv;

    cnv.cpv = key;

    pair->key = cnv.pv;

  }

}

static inline void setValue(wHashTable* table, wKeyValuePair* pair, const void* value)

{

  WINPR_ASSERT(table);

  if (!pair)

    return;

  disposeValue(table, pair->value);

  if (table->value.fnObjectNew)

    pair->value = table->value.fnObjectNew(value);

  else

  {

    union

    {

      const void* cpv;

      void* pv;

    } cnv;

    cnv.cpv = value;

    pair->value = cnv.pv;

  }

}

/**

 * C equivalent of the C# Hashtable Class:

 * http://msdn.microsoft.com/en-us/library/system.collections.hashtable.aspx

 */

/**

 * Properties

 */

/**

 * Gets the number of key/value pairs contained in the HashTable.

 */

size_t HashTable_Count(wHashTable* table)

{

  WINPR_ASSERT(table);

  return table->numOfElements;

}

/**

 * Methods

 */

/**

 * Adds an element with the specified key and value into the HashTable.

 */

#if defined(WITH_WINPR_DEPRECATED)

int HashTable_Add(wHashTable* table, const void* key, const void* value)

{

  if (!HashTable_Insert(table, key, value))

    return -1;

  return 0;

}

#endif

BOOL HashTable_Insert(wHashTable* table, const void* key, const void* value)

{

  BOOL rc = FALSE;

  UINT32 hashValue = 0;

  wKeyValuePair* pair = nullptr;

  wKeyValuePair* newPair = nullptr;

  WINPR_ASSERT(table);

  if (!key || !value)

    return FALSE;

  if (table->synchronized)

    EnterCriticalSection(&table->lock);

  hashValue = table->hash(key) % table->numOfBuckets;

  pair = table->bucketArray[hashValue];

  while (pair && !HashTable_Equals(table, pair, key))

    pair = pair->next;

  if (pair)

  {

    if (pair->markedForRemove)

    {

      /* this entry was set to be removed but will be recycled instead */

      table->pendingRemoves--;

      pair->markedForRemove = FALSE;

      table->numOfElements++;

    }

    if (pair->key != key)

    {

      setKey(table, pair, key);

    }

    if (pair->value != value)

    {

      setValue(table, pair, value);

    }

    rc = TRUE;

  }

  else

  {

    newPair = (wKeyValuePair*)calloc(1, sizeof(wKeyValuePair));

    if (newPair)

    {

      setKey(table, newPair, key);

      setValue(table, newPair, value);

      newPair->next = table->bucketArray[hashValue];

      newPair->markedForRemove = FALSE;

      table->bucketArray[hashValue] = newPair;

      table->numOfElements++;

      if (!table->foreachRecursionLevel && table->upperRehashThreshold > table->idealRatio)

      {

        float elementToBucketRatio =

            (float)table->numOfElements / (float)table->numOfBuckets;

        if (elementToBucketRatio > table->upperRehashThreshold)

          HashTable_Rehash(table, 0);

      }

      rc = TRUE;

    }

  }

  if (table->synchronized)

    LeaveCriticalSection(&table->lock);

  return rc;

}

/**

 * Removes the element with the specified key from the HashTable.

 */

BOOL HashTable_Remove(wHashTable* table, const void* key)

{

  UINT32 hashValue = 0;

  BOOL status = TRUE;

  wKeyValuePair* pair = nullptr;

  wKeyValuePair* previousPair = nullptr;

  WINPR_ASSERT(table);

  if (!key)

    return FALSE;

  if (table->synchronized)

    EnterCriticalSection(&table->lock);

  hashValue = table->hash(key) % table->numOfBuckets;

  pair = table->bucketArray[hashValue];

  while (pair && !HashTable_Equals(table, pair, key))

  {

    previousPair = pair;

    pair = pair->next;

  }

  if (!pair)

  {

    status = FALSE;

    goto out;

  }

  if (table->foreachRecursionLevel)

  {

    /* if we are running a HashTable_Foreach, just mark the entry for removal */

    pair->markedForRemove = TRUE;

    table->pendingRemoves++;

    table->numOfElements--;

    goto out;

  }

  if (previousPair)

    previousPair->next = pair->next;

  else

    table->bucketArray[hashValue] = pair->next;

  disposePair(table, pair);

  table->numOfElements--;

  if (!table->foreachRecursionLevel && table->lowerRehashThreshold > 0.0f)

  {

    float elementToBucketRatio = (float)table->numOfElements / (float)table->numOfBuckets;

    if (elementToBucketRatio < table->lowerRehashThreshold)

      HashTable_Rehash(table, 0);

  }

out:

  if (table->synchronized)

    LeaveCriticalSection(&table->lock);

  return status;

}

/**

 * Get an item value using key

 */

void* HashTable_GetItemValue(wHashTable* table, const void* key)

{

  void* value = nullptr;

  wKeyValuePair* pair = nullptr;

  WINPR_ASSERT(table);

  if (!key)

    return nullptr;

  if (table->synchronized)

    EnterCriticalSection(&table->lock);

  pair = HashTable_Get(table, key);

  if (pair && !pair->markedForRemove)

    value = pair->value;

  if (table->synchronized)

    LeaveCriticalSection(&table->lock);

  return value;

}

/**

 * Set an item value using key

 */

BOOL HashTable_SetItemValue(wHashTable* table, const void* key, const void* value)

{

  BOOL status = TRUE;

  wKeyValuePair* pair = nullptr;

  WINPR_ASSERT(table);

  if (!key)

    return FALSE;

  if (table->synchronized)

    EnterCriticalSection(&table->lock);

  pair = HashTable_Get(table, key);

  if (!pair || pair->markedForRemove)

    status = FALSE;

  else

  {

    setValue(table, pair, value);

  }

  if (table->synchronized)

    LeaveCriticalSection(&table->lock);

  return status;

}

/**

 * Removes all elements from the HashTable.

 */

void HashTable_Clear(wHashTable* table)

{

  wKeyValuePair* nextPair = nullptr;

  WINPR_ASSERT(table);

  if (table->synchronized)

    EnterCriticalSection(&table->lock);

  for (size_t index = 0; index < table->numOfBuckets; index++)

  {

    wKeyValuePair* pair = table->bucketArray[index];

    while (pair)

    {

      nextPair = pair->next;

      if (table->foreachRecursionLevel)

      {

        /* if we're in a foreach we just mark the entry for removal */

        pair->markedForRemove = TRUE;

        table->pendingRemoves++;

      }

      else

      {

        disposePair(table, pair);

        pair = nextPair;

      }

    }

    table->bucketArray[index] = nullptr;

  }

  table->numOfElements = 0;

  if (table->foreachRecursionLevel == 0)

    HashTable_Rehash(table, 5);

  if (table->synchronized)

    LeaveCriticalSection(&table->lock);

}

/**

 * Gets the list of keys as an array

 */

size_t HashTable_GetKeys(wHashTable* table, ULONG_PTR** ppKeys)

{

  size_t iKey = 0;

  size_t count = 0;

  ULONG_PTR* pKeys = nullptr;

  wKeyValuePair* nextPair = nullptr;

  WINPR_ASSERT(table);

  if (table->synchronized)

    EnterCriticalSection(&table->lock);

  iKey = 0;

  count = table->numOfElements;

  if (ppKeys)

    *ppKeys = nullptr;

  if (count < 1)

  {

    if (table->synchronized)

      LeaveCriticalSection(&table->lock);

    return 0;

  }

  pKeys = (ULONG_PTR*)calloc(count, sizeof(ULONG_PTR));

  if (!pKeys)

  {

    if (table->synchronized)

      LeaveCriticalSection(&table->lock);

    return 0;

  }

  for (size_t index = 0; index < table->numOfBuckets; index++)

  {

    wKeyValuePair* pair = table->bucketArray[index];

    while (pair)

    {

      nextPair = pair->next;

      if (!pair->markedForRemove)

        pKeys[iKey++] = (ULONG_PTR)pair->key;

      pair = nextPair;

    }

  }

  if (table->synchronized)

    LeaveCriticalSection(&table->lock);

  if (ppKeys)

    *ppKeys = pKeys;

  else

    free(pKeys);

  return count;

}

BOOL HashTable_Foreach(wHashTable* table, HASH_TABLE_FOREACH_FN fn, VOID* arg)

{

  BOOL ret = TRUE;

  WINPR_ASSERT(table);

  WINPR_ASSERT(fn);

  if (table->synchronized)

    EnterCriticalSection(&table->lock);

  table->foreachRecursionLevel++;

  for (size_t index = 0; index < table->numOfBuckets; index++)

  {

    for (wKeyValuePair* pair = table->bucketArray[index]; pair; pair = pair->next)

    {

      if (!pair->markedForRemove && !fn(pair->key, pair->value, arg))

      {

        ret = FALSE;

        goto out;

      }

    }

  }

  table->foreachRecursionLevel--;

  if (!table->foreachRecursionLevel && table->pendingRemoves)

  {

    /* if we're the last recursive foreach call, let's do the cleanup if needed */

    wKeyValuePair** prevPtr = nullptr;

    for (size_t index = 0; index < table->numOfBuckets; index++)

    {

      wKeyValuePair* nextPair = nullptr;

      prevPtr = &table->bucketArray[index];

      for (wKeyValuePair* pair = table->bucketArray[index]; pair;)

      {

        nextPair = pair->next;

        if (pair->markedForRemove)

        {

          disposePair(table, pair);

          *prevPtr = nextPair;

        }

        else

        {

          prevPtr = &pair->next;

        }

        pair = nextPair;

      }

    }

    table->pendingRemoves = 0;

  }

out:

  if (table->synchronized)

    LeaveCriticalSection(&table->lock);

  return ret;

}

/**

 * Determines whether the HashTable contains a specific key.

 */

BOOL HashTable_Contains(wHashTable* table, const void* key)

{

  BOOL status = 0;

  wKeyValuePair* pair = nullptr;

  WINPR_ASSERT(table);

  if (!key)

    return FALSE;

  if (table->synchronized)

    EnterCriticalSection(&table->lock);

  pair = HashTable_Get(table, key);

  status = (pair && !pair->markedForRemove);

  if (table->synchronized)

    LeaveCriticalSection(&table->lock);

  return status;

}

/**

 * Determines whether the HashTable contains a specific key.

 */

BOOL HashTable_ContainsKey(wHashTable* table, const void* key)

{

  BOOL status = 0;

  wKeyValuePair* pair = nullptr;

  WINPR_ASSERT(table);

  if (!key)

    return FALSE;

  if (table->synchronized)

    EnterCriticalSection(&table->lock);

  pair = HashTable_Get(table, key);

  status = (pair && !pair->markedForRemove);

  if (table->synchronized)

    LeaveCriticalSection(&table->lock);

  return status;

}

/**

 * Determines whether the HashTable contains a specific value.

 */

BOOL HashTable_ContainsValue(wHashTable* table, const void* value)

{

  BOOL status = FALSE;

  WINPR_ASSERT(table);

  if (!value)

    return FALSE;

  if (table->synchronized)

    EnterCriticalSection(&table->lock);

  for (size_t index = 0; index < table->numOfBuckets; index++)

  {

    wKeyValuePair* pair = table->bucketArray[index];

    while (pair)

    {

      if (!pair->markedForRemove && HashTable_Equals(table, pair, value))

      {

        status = TRUE;

        break;

      }

      pair = pair->next;

    }

    if (status)

      break;

  }

  if (table->synchronized)

    LeaveCriticalSection(&table->lock);

  return status;

}

/**

 * Construction, Destruction

 */

wHashTable* HashTable_New(BOOL synchronized)

{

  wHashTable* table = (wHashTable*)calloc(1, sizeof(wHashTable));

  if (!table)

    goto fail;

  table->synchronized = synchronized;

  if (!InitializeCriticalSectionAndSpinCount(&(table->lock), 4000))

    goto fail;

  table->numOfBuckets = 64;

  table->numOfElements = 0;

  table->bucketArray = (wKeyValuePair**)calloc(table->numOfBuckets, sizeof(wKeyValuePair*));

  if (!table->bucketArray)

    goto fail;

  table->idealRatio = 3.0f;

  table->lowerRehashThreshold = 0.0f;

  table->upperRehashThreshold = 15.0f;

  table->hash = HashTable_PointerHash;

  table->key.fnObjectEquals = HashTable_PointerCompare;

  table->value.fnObjectEquals = HashTable_PointerCompare;

  return table;

fail:

  WINPR_PRAGMA_DIAG_PUSH

  WINPR_PRAGMA_DIAG_IGNORED_MISMATCHED_DEALLOC

  HashTable_Free(table);

  WINPR_PRAGMA_DIAG_POP

  return nullptr;

}

void HashTable_Free(wHashTable* table)

{

  wKeyValuePair* pair = nullptr;

  wKeyValuePair* nextPair = nullptr;

  if (!table)

    return;

  if (table->bucketArray)

  {

    for (size_t index = 0; index < table->numOfBuckets; index++)

    {

      pair = table->bucketArray[index];

      while (pair)

      {

        nextPair = pair->next;

        disposePair(table, pair);

        pair = nextPair;

      }

    }

    free((void*)table->bucketArray);

  }

  DeleteCriticalSection(&(table->lock));

  free(table);

}

void HashTable_Lock(wHashTable* table)

{

  WINPR_ASSERT(table);

  EnterCriticalSection(&table->lock);

}

void HashTable_Unlock(wHashTable* table)

{

  WINPR_ASSERT(table);

  LeaveCriticalSection(&table->lock);

}

wObject* HashTable_KeyObject(wHashTable* table)

{

  WINPR_ASSERT(table);

  return &table->key;

}

wObject* HashTable_ValueObject(wHashTable* table)

{

  WINPR_ASSERT(table);

  return &table->value;

}

BOOL HashTable_SetHashFunction(wHashTable* table, HASH_TABLE_HASH_FN fn)

{

  WINPR_ASSERT(table);

  table->hash = fn;

  return fn != nullptr;

}

BOOL HashTable_SetupForStringData(wHashTable* table, BOOL stringValues)

{

  wObject* obj = nullptr;

  if (!HashTable_SetHashFunction(table, HashTable_StringHash))

    return FALSE;

  obj = HashTable_KeyObject(table);

  obj->fnObjectEquals = HashTable_StringCompare;

  obj->fnObjectNew = HashTable_StringClone;

  obj->fnObjectFree = HashTable_StringFree;

  if (stringValues)

  {

    obj = HashTable_ValueObject(table);

    obj->fnObjectEquals = HashTable_StringCompare;

    obj->fnObjectNew = HashTable_StringClone;

    obj->fnObjectFree = HashTable_StringFree;

  }

  return TRUE;

}