path: root/pvr-source/services4/srvkm/common/hash.c

/*************************************************************************/ /*!
@Title          Self scaling hash tables.
@Copyright      Copyright (c) Imagination Technologies Ltd. All Rights Reserved
@Description
   Implements simple self scaling hash tables. Hash collisions are
   handled by chaining entries together. Hash tables are increased in
   size when they become more than (50%?) full and decreased in size
   when less than (25%?) full. Hash tables are never decreased below
   their initial size.
@License        Dual MIT/GPLv2

The contents of this file are subject to the MIT license as set out below.

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.

Alternatively, the contents of this file may be used under the terms of
the GNU General Public License Version 2 ("GPL") in which case the provisions
of GPL are applicable instead of those above.

If you wish to allow use of your version of this file only under the terms of
GPL, and not to allow others to use your version of this file under the terms
of the MIT license, indicate your decision by deleting the provisions above
and replace them with the notice and other provisions required by GPL as set
out in the file called "GPL-COPYING" included in this distribution. If you do
not delete the provisions above, a recipient may use your version of this file
under the terms of either the MIT license or GPL.

This License is also included in this distribution in the file called
"MIT-COPYING".

EXCEPT AS OTHERWISE STATED IN A NEGOTIATED AGREEMENT: (A) 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; AND (B) 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.
*/ /**************************************************************************/

#include "pvr_debug.h"
#include "img_defs.h"
#include "services.h"
#include "servicesint.h"
#include "hash.h"
#include "osfunc.h"

#define PRIVATE_MAX(a,b) ((a)>(b)?(a):(b))

#define	KEY_TO_INDEX(pHash, key, uSize) \
	((pHash)->pfnHashFunc((pHash)->uKeySize, (key), (uSize)) % (uSize))

#define	KEY_COMPARE(pHash, pKey1, pKey2) \
	((pHash)->pfnKeyComp((pHash)->uKeySize, (pKey1), (pKey2)))

/* Each entry in a hash table is placed into a bucket */
struct _BUCKET_
{
	/* the next bucket on the same chain */
	struct _BUCKET_ *pNext;

	/* entry value */
	IMG_UINTPTR_T v;

	/* entry key */
	IMG_UINTPTR_T k[];		/* PRQA S 0642 */ /* override dynamic array declaration warning */
};
typedef struct _BUCKET_ BUCKET;

struct _HASH_TABLE_
{
	/* the hash table array */
	BUCKET **ppBucketTable;

	/* current size of the hash table */
	IMG_UINT32 uSize;

	/* number of entries currently in the hash table */
	IMG_UINT32 uCount;

	/* the minimum size that the hash table should be re-sized to */
	IMG_UINT32 uMinimumSize;

	/* size of key in bytes */
	IMG_UINT32 uKeySize;

	/* hash function */
	HASH_FUNC *pfnHashFunc;

	/* key comparison function */
	HASH_KEY_COMP *pfnKeyComp;
};

/*!
******************************************************************************
	@Function   	HASH_Func_Default

	@Description    Hash function intended for hashing keys composed of
                    IMG_UINTPTR_T arrays.

	@Input          uKeySize - the size of the hash key, in bytes.
	@Input          pKey - a pointer to the key to hash.
	@Input          uHashTabLen - the length of the hash table.
    
	@Return 	    the hash value.
******************************************************************************/
IMG_UINT32
HASH_Func_Default (IMG_SIZE_T uKeySize, IMG_VOID *pKey, IMG_UINT32 uHashTabLen)
{
	IMG_UINTPTR_T *p = (IMG_UINTPTR_T *)pKey;
	IMG_UINT32 uKeyLen = (IMG_UINT32)(uKeySize / sizeof(IMG_UINTPTR_T));
	IMG_UINT32 ui;
	IMG_UINT32 uHashKey = 0;

	PVR_UNREFERENCED_PARAMETER(uHashTabLen);

	PVR_ASSERT((uKeySize % sizeof(IMG_UINTPTR_T)) == 0);

	for (ui = 0; ui < uKeyLen; ui++)
	{
		IMG_UINT32 uHashPart = (IMG_UINT32)*p++;

		uHashPart += (uHashPart << 12);
		uHashPart ^= (uHashPart >> 22);
		uHashPart += (uHashPart << 4);
		uHashPart ^= (uHashPart >> 9);
		uHashPart += (uHashPart << 10);
		uHashPart ^= (uHashPart >> 2);
		uHashPart += (uHashPart << 7);
		uHashPart ^= (uHashPart >> 12);

		uHashKey += uHashPart;
	}

	return uHashKey;
}

/*!
******************************************************************************
	@Function   	HASH_Key_Comp_Default

	@Description    Compares keys composed of IMG_UINTPTR_T arrays.

	@Input          uKeySize - the size of the hash key, in bytes.
	@Input          pKey1 - pointer to first hash key to compare.
	@Input          pKey2 - pointer to second hash key to compare.
	@Return 	    IMG_TRUE  - the keys match.
                    IMG_FALSE - the keys don't match.
******************************************************************************/
IMG_BOOL
HASH_Key_Comp_Default (IMG_SIZE_T uKeySize, IMG_VOID *pKey1, IMG_VOID *pKey2)
{
	IMG_UINTPTR_T *p1 = (IMG_UINTPTR_T *)pKey1;
	IMG_UINTPTR_T *p2 = (IMG_UINTPTR_T *)pKey2;
	IMG_UINT32 uKeyLen = (IMG_UINT32)(uKeySize / sizeof(IMG_UINTPTR_T));
	IMG_UINT32 ui;

	PVR_ASSERT((uKeySize % sizeof(IMG_UINTPTR_T)) == 0);

	for (ui = 0; ui < uKeyLen; ui++)
	{
		if (*p1++ != *p2++)
			return IMG_FALSE;
	}

	return IMG_TRUE;
}

/*!
******************************************************************************
	@Function   	_ChainInsert

	@Description    Insert a bucket into the appropriate hash table chain.

	@Input          pBucket - the bucket
	@Input          ppBucketTable - the hash table
	@Input          uSize - the size of the hash table
    
	@Return         PVRSRV_ERROR
******************************************************************************/
static PVRSRV_ERROR
_ChainInsert (HASH_TABLE *pHash, BUCKET *pBucket, BUCKET **ppBucketTable, IMG_UINT32 uSize)
{
	IMG_UINT32 uIndex;

	PVR_ASSERT (pBucket != IMG_NULL);
	PVR_ASSERT (ppBucketTable != IMG_NULL);
	PVR_ASSERT (uSize != 0);

	if ((pBucket == IMG_NULL) || (ppBucketTable == IMG_NULL) || (uSize == 0))
	{
		PVR_DPF((PVR_DBG_ERROR, "_ChainInsert: invalid parameter"));
		return PVRSRV_ERROR_INVALID_PARAMS;
	}

	uIndex = KEY_TO_INDEX(pHash, pBucket->k, uSize);	/* PRQA S 0432,0541 */ /* ignore dynamic array warning */
	pBucket->pNext = ppBucketTable[uIndex];
	ppBucketTable[uIndex] = pBucket;

	return PVRSRV_OK;
}

/*!
******************************************************************************
	@Function   	_Rehash

	@Description   	Iterate over every entry in an old hash table and
                    rehash into the new table.

	@Input          ppOldTable - the old hash table
	@Input          uOldSize - the size of the old hash table
	@Input          ppNewTable - the new hash table
	@Input          uNewSize - the size of the new hash table
    
	@Return         None
******************************************************************************/
static PVRSRV_ERROR
_Rehash (HASH_TABLE *pHash,
	 BUCKET **ppOldTable, IMG_UINT32 uOldSize,
         BUCKET **ppNewTable, IMG_UINT32 uNewSize)
{
	IMG_UINT32 uIndex;
	for (uIndex=0; uIndex< uOldSize; uIndex++)
    {
		BUCKET *pBucket;
		pBucket = ppOldTable[uIndex];
		while (pBucket != IMG_NULL)
		{
			PVRSRV_ERROR eError;
			BUCKET *pNextBucket = pBucket->pNext;
			eError = _ChainInsert (pHash, pBucket, ppNewTable, uNewSize);
			if (eError != PVRSRV_OK)
			{
				PVR_DPF((PVR_DBG_ERROR, "_Rehash: call to _ChainInsert failed"));
				return eError;
			}
			pBucket = pNextBucket;
		}
    }
	return PVRSRV_OK;
}

/*!
******************************************************************************
	@Function   	_Resize

	@Description    Attempt to resize a hash table, failure to allocate a
                    new larger hash table is not considered a hard failure.
                    We simply continue and allow the table to fill up, the
	            	effect is to allow hash chains to become longer.

	@Input          pHash - Hash table to resize.
    @Input          uNewSize - Required table size.
	@Return         IMG_TRUE Success
	            	IMG_FALSE Failed
******************************************************************************/
static IMG_BOOL
_Resize (HASH_TABLE *pHash, IMG_UINT32 uNewSize)
{
	if (uNewSize != pHash->uSize)
    {
		BUCKET **ppNewTable;
        IMG_UINT32 uIndex;

		PVR_DPF ((PVR_DBG_MESSAGE,
                  "HASH_Resize: oldsize=0x%x  newsize=0x%x  count=0x%x",
				pHash->uSize, uNewSize, pHash->uCount));

		OSAllocMem(PVRSRV_PAGEABLE_SELECT,
                      sizeof (BUCKET *) * uNewSize,
                      (IMG_PVOID*)&ppNewTable, IMG_NULL,
					  "Hash Table Buckets");
		if (ppNewTable == IMG_NULL)
            return IMG_FALSE;

        for (uIndex=0; uIndex<uNewSize; uIndex++)
            ppNewTable[uIndex] = IMG_NULL;

        if (_Rehash (pHash, pHash->ppBucketTable, pHash->uSize, ppNewTable, uNewSize) != PVRSRV_OK)
		{
			return IMG_FALSE;
		}

        OSFreeMem (PVRSRV_PAGEABLE_SELECT, sizeof(BUCKET *)*pHash->uSize, pHash->ppBucketTable, IMG_NULL);
        /*not nulling pointer, being reassigned just below*/
        pHash->ppBucketTable = ppNewTable;
        pHash->uSize = uNewSize;
    }
    return IMG_TRUE;
}


/*!
******************************************************************************
	@Function   	HASH_Create_Extended

	@Description    Create a self scaling hash table, using the supplied
                    key size, and the supplied hash and key comparsion
                    functions.

	@Input          uInitialLen - initial and minimum length of the
                    hash table, where the length refers to the number
                    of entries in the hash table, not its size in
                    bytes.
	@Input          uKeySize - the size of the key, in bytes.
	@Input          pfnHashFunc - pointer to hash function.
    @Input          pfnKeyComp - pointer to key comparsion function.
	@Return         IMG_NULL or hash table handle.
******************************************************************************/
HASH_TABLE * HASH_Create_Extended (IMG_UINT32 uInitialLen, IMG_SIZE_T uKeySize, HASH_FUNC *pfnHashFunc, HASH_KEY_COMP *pfnKeyComp)
{
	HASH_TABLE *pHash;
	IMG_UINT32 uIndex;

	PVR_DPF ((PVR_DBG_MESSAGE, "HASH_Create_Extended: InitialSize=0x%x", uInitialLen));

	if(OSAllocMem(PVRSRV_PAGEABLE_SELECT,
					sizeof(HASH_TABLE),
					(IMG_VOID **)&pHash, IMG_NULL,
					"Hash Table") != PVRSRV_OK)
	{
		return IMG_NULL;
	}

	pHash->uCount = 0;
	pHash->uSize = uInitialLen;
	pHash->uMinimumSize = uInitialLen;
	pHash->uKeySize = (IMG_UINT32)uKeySize;
	pHash->pfnHashFunc = pfnHashFunc;
	pHash->pfnKeyComp = pfnKeyComp;

	OSAllocMem(PVRSRV_PAGEABLE_SELECT,
                  sizeof (BUCKET *) * pHash->uSize,
                  (IMG_PVOID*)&pHash->ppBucketTable, IMG_NULL,
				  "Hash Table Buckets");

	if (pHash->ppBucketTable == IMG_NULL)
    {
		OSFreeMem(PVRSRV_PAGEABLE_SELECT, sizeof(HASH_TABLE), pHash, IMG_NULL);
		/*not nulling pointer, out of scope*/
		return IMG_NULL;
    }

	for (uIndex=0; uIndex<pHash->uSize; uIndex++)
		pHash->ppBucketTable[uIndex] = IMG_NULL;
	return pHash;
}

/*!
******************************************************************************
	@Function   	HASH_Create

	@Description    Create a self scaling hash table with a key
                    consisting of a single IMG_UINTPTR_T, and using
                    the default hash and key comparison functions.

	@Input          uInitialLen - initial and minimum length of the
                    hash table, where the length refers to the
                    number of entries in the hash table, not its size
                    in bytes.
	@Return 	    IMG_NULL or hash table handle.
******************************************************************************/
HASH_TABLE * HASH_Create (IMG_UINT32 uInitialLen)
{
	return HASH_Create_Extended(uInitialLen, sizeof(IMG_UINTPTR_T),
		&HASH_Func_Default, &HASH_Key_Comp_Default);
}

/*!
******************************************************************************
	@Function       HASH_Delete

	@Description    Delete a hash table created by HASH_Create_Extended or
                    HASH_Create.  All entries in the table must have been
                    removed before calling this function.

	@Input          pHash - hash table
    
	@Return 	    None
******************************************************************************/
IMG_VOID
HASH_Delete (HASH_TABLE *pHash)
{
	if (pHash != IMG_NULL)
    {
		PVR_DPF ((PVR_DBG_MESSAGE, "HASH_Delete"));

		PVR_ASSERT (pHash->uCount==0);
		if(pHash->uCount != 0)
		{
			PVR_DPF ((PVR_DBG_ERROR, "HASH_Delete: leak detected in hash table!"));
			PVR_DPF ((PVR_DBG_ERROR, "Likely Cause: client drivers not freeing alocations before destroying devmemcontext"));
		}
		OSFreeMem(PVRSRV_PAGEABLE_SELECT, sizeof(BUCKET *)*pHash->uSize, pHash->ppBucketTable, IMG_NULL);
		pHash->ppBucketTable = IMG_NULL;
		OSFreeMem(PVRSRV_PAGEABLE_SELECT, sizeof(HASH_TABLE), pHash, IMG_NULL);
		/*not nulling pointer, copy on stack*/
    }
}

/*!
******************************************************************************
	@Function   	HASH_Insert_Extended

	@Description    Insert a key value pair into a hash table created
                    with HASH_Create_Extended.

	@Input          pHash - the hash table.
	@Input          pKey - pointer to the key.
	@Input          v - the value associated with the key.

	@Return 	    IMG_TRUE  - success
	            	IMG_FALSE  - failure
******************************************************************************/
IMG_BOOL
HASH_Insert_Extended (HASH_TABLE *pHash, IMG_VOID *pKey, IMG_UINTPTR_T v)
{
	BUCKET *pBucket;

	PVR_DPF ((PVR_DBG_MESSAGE,
              "HASH_Insert_Extended: Hash=0x%08x, pKey=0x%08x, v=0x%x",
              (IMG_UINTPTR_T)pHash, (IMG_UINTPTR_T)pKey, v));

	PVR_ASSERT (pHash != IMG_NULL);

	if (pHash == IMG_NULL)
	{
		PVR_DPF((PVR_DBG_ERROR, "HASH_Insert_Extended: invalid parameter"));
		return IMG_FALSE;
	}

	if(OSAllocMem(PVRSRV_PAGEABLE_SELECT,
					sizeof(BUCKET) + pHash->uKeySize,
					(IMG_VOID **)&pBucket, IMG_NULL,
					"Hash Table entry") != PVRSRV_OK)
	{
		return IMG_FALSE;
	}

	pBucket->v = v;
	/* PRQA S 0432,0541 1 */ /* ignore warning about dynamic array k (linux)*/
	OSMemCopy(pBucket->k, pKey, pHash->uKeySize);
	if (_ChainInsert (pHash, pBucket, pHash->ppBucketTable, pHash->uSize) != PVRSRV_OK)
	{
		OSFreeMem(PVRSRV_PAGEABLE_SELECT,
				  sizeof(BUCKET) + pHash->uKeySize,
				  pBucket, IMG_NULL);
		return IMG_FALSE;
	}

	pHash->uCount++;

	/* check if we need to think about re-balencing */
	if (pHash->uCount << 1 > pHash->uSize)
    {
        /* Ignore the return code from _Resize because the hash table is
           still in a valid state and although not ideally sized, it is still
           functional */
        _Resize (pHash, pHash->uSize << 1);
    }


	return IMG_TRUE;
}

/*!
******************************************************************************
	@Function   	HASH_Insert

	@Description    Insert a key value pair into a hash table created with
                    HASH_Create.

	@Input          pHash - the hash table.
	@Input          k - the key value.
	@Input          v - the value associated with the key.

	@Return 	    IMG_TRUE - success.
	            	IMG_FALSE - failure.
******************************************************************************/
IMG_BOOL
HASH_Insert (HASH_TABLE *pHash, IMG_UINTPTR_T k, IMG_UINTPTR_T v)
{
	PVR_DPF ((PVR_DBG_MESSAGE,
              "HASH_Insert: Hash=0x%x, k=0x%x, v=0x%x",
              (IMG_UINTPTR_T)pHash, k, v));

	return HASH_Insert_Extended(pHash, &k, v);
}

/*!
******************************************************************************
	@Function   	HASH_Remove_Extended

	@Description    Remove a key from a hash table created with
                    HASH_Create_Extended.

	@Input          pHash - the hash table.
	@Input          pKey - pointer to key.

	@Return 	    0 if the key is missing, or the value associated
                    with the key.
******************************************************************************/
IMG_UINTPTR_T
HASH_Remove_Extended(HASH_TABLE *pHash, IMG_VOID *pKey)
{
	BUCKET **ppBucket;
	IMG_UINT32 uIndex;

	PVR_DPF ((PVR_DBG_MESSAGE, "HASH_Remove_Extended: Hash=0x%x, pKey=0x%x",
			(IMG_UINTPTR_T)pHash, (IMG_UINTPTR_T)pKey));

	PVR_ASSERT (pHash != IMG_NULL);

	if (pHash == IMG_NULL)
	{
		PVR_DPF((PVR_DBG_ERROR, "HASH_Remove_Extended: Null hash table"));
		return 0;
	}

	uIndex = KEY_TO_INDEX(pHash, pKey, pHash->uSize);

	for (ppBucket = &(pHash->ppBucketTable[uIndex]); *ppBucket != IMG_NULL; ppBucket = &((*ppBucket)->pNext))
	{
		/* PRQA S 0432,0541 1 */ /* ignore warning about dynamic array k */
		if (KEY_COMPARE(pHash, (*ppBucket)->k, pKey))
		{
			BUCKET *pBucket = *ppBucket;
			IMG_UINTPTR_T v = pBucket->v;
			(*ppBucket) = pBucket->pNext;

			OSFreeMem(PVRSRV_PAGEABLE_SELECT, sizeof(BUCKET) + pHash->uKeySize, pBucket, IMG_NULL);
			/*not nulling original pointer, already overwritten*/

			pHash->uCount--;

			/* check if we need to think about re-balencing */
			if (pHash->uSize > (pHash->uCount << 2) &&
                pHash->uSize > pHash->uMinimumSize)
            {
                /* Ignore the return code from _Resize because the
                   hash table is still in a valid state and although
                   not ideally sized, it is still functional */
				_Resize (pHash,
                         PRIVATE_MAX (pHash->uSize >> 1,
                                      pHash->uMinimumSize));
            }

			PVR_DPF ((PVR_DBG_MESSAGE,
                      "HASH_Remove_Extended: Hash=0x%x, pKey=0x%x = 0x%x",
                      (IMG_UINTPTR_T)pHash, (IMG_UINTPTR_T)pKey, v));
			return v;
		}
	}
	PVR_DPF ((PVR_DBG_MESSAGE,
              "HASH_Remove_Extended: Hash=0x%x, pKey=0x%x = 0x0 !!!!",
              (IMG_UINTPTR_T)pHash, (IMG_UINTPTR_T)pKey));
	return 0;
}

/*!
******************************************************************************
	@Function   	HASH_Remove

	@Description    Remove a key value pair from a hash table created
                    with HASH_Create.

	@Input          pHash - the hash table
	@Input          k - the key

	@Return         0 if the key is missing, or the value associated
                    with the key.
******************************************************************************/
IMG_UINTPTR_T
HASH_Remove (HASH_TABLE *pHash, IMG_UINTPTR_T k)
{
	PVR_DPF ((PVR_DBG_MESSAGE, "HASH_Remove: Hash=0x%x, k=0x%x",
			(IMG_UINTPTR_T)pHash, k));

	return HASH_Remove_Extended(pHash, &k);
}

/*!
******************************************************************************
	@Function   	HASH_Retrieve_Extended

	@Description    Retrieve a value from a hash table created with
                    HASH_Create_Extended.

	@Input          pHash - the hash table.
	@Input          pKey - pointer to the key.

	@Return 	    0 if the key is missing, or the value associated with
                    the key.
******************************************************************************/
IMG_UINTPTR_T
HASH_Retrieve_Extended (HASH_TABLE *pHash, IMG_VOID *pKey)
{
	BUCKET **ppBucket;
	IMG_UINT32 uIndex;

	PVR_DPF ((PVR_DBG_MESSAGE, "HASH_Retrieve_Extended: Hash=0x%x, pKey=0x%x",
			(IMG_UINTPTR_T)pHash, (IMG_UINTPTR_T)pKey));

	PVR_ASSERT (pHash != IMG_NULL);

	if (pHash == IMG_NULL)
	{
		PVR_DPF((PVR_DBG_ERROR, "HASH_Retrieve_Extended: Null hash table"));
		return 0;
	}

	uIndex = KEY_TO_INDEX(pHash, pKey, pHash->uSize);

	for (ppBucket = &(pHash->ppBucketTable[uIndex]); *ppBucket != IMG_NULL; ppBucket = &((*ppBucket)->pNext))
	{
		/* PRQA S 0432,0541 1 */ /* ignore warning about dynamic array k */
		if (KEY_COMPARE(pHash, (*ppBucket)->k, pKey))
		{
			BUCKET *pBucket = *ppBucket;
			IMG_UINTPTR_T v = pBucket->v;

			PVR_DPF ((PVR_DBG_MESSAGE,
                      "HASH_Retrieve: Hash=0x%x, pKey=0x%x = 0x%x",
                      (IMG_UINTPTR_T)pHash, (IMG_UINTPTR_T)pKey, v));
			return v;
		}
	}
	PVR_DPF ((PVR_DBG_MESSAGE,
              "HASH_Retrieve: Hash=0x%x, pKey=0x%x = 0x0 !!!!",
              (IMG_UINTPTR_T)pHash, (IMG_UINTPTR_T)pKey));
	return 0;
}

/*!
******************************************************************************
	@Function   	HASH_Retrieve

	@Description    Retrieve a value from a hash table created with
                    HASH_Create.

	@Input          pHash - the hash table
	@Input          k - the key
	@Return 	    0 if the key is missing, or the value associated with
                    the key.
******************************************************************************/
IMG_UINTPTR_T
HASH_Retrieve (HASH_TABLE *pHash, IMG_UINTPTR_T k)
{
	PVR_DPF ((PVR_DBG_MESSAGE, "HASH_Retrieve: Hash=0x%x, k=0x%x",
			(IMG_UINTPTR_T)pHash, k));
	return HASH_Retrieve_Extended(pHash, &k);
}

/*!
******************************************************************************
	@Function   	HASH_Iterate

	@Description    Iterate over every entry in the hash table

	@Input          pHash - the old hash table
	@Input          pfnCallback - the size of the old hash table

	@Return 	    Callback error if any, otherwise PVRSRV_OK
******************************************************************************/
PVRSRV_ERROR
HASH_Iterate(HASH_TABLE *pHash, HASH_pfnCallback pfnCallback)
{
	IMG_UINT32 uIndex;
	for (uIndex=0; uIndex < pHash->uSize; uIndex++)
	{
		BUCKET *pBucket;
		pBucket = pHash->ppBucketTable[uIndex];
		while (pBucket != IMG_NULL)
		{
			PVRSRV_ERROR eError;
			BUCKET *pNextBucket = pBucket->pNext;
			
			eError = pfnCallback((IMG_UINTPTR_T) ((IMG_VOID *) *(pBucket->k)), (IMG_UINTPTR_T) pBucket->v);

			/* The callback might want us to break out early */
			if (eError != PVRSRV_OK)
				return eError;

			pBucket = pNextBucket;
		}
	}
	return PVRSRV_OK;
}

#ifdef HASH_TRACE
/*!
******************************************************************************
	@Function   	HASH_Dump

	@Description   	To dump the contents of a hash table in human readable
                    form.

	@Input          pHash - the hash table

	@Return 	    None
******************************************************************************/
IMG_VOID
HASH_Dump (HASH_TABLE *pHash)
{
	IMG_UINT32 uIndex;
	IMG_UINT32 uMaxLength=0;
	IMG_UINT32 uEmptyCount=0;

	PVR_ASSERT (pHash != IMG_NULL);
	for (uIndex=0; uIndex<pHash->uSize; uIndex++)
	{
		BUCKET *pBucket;
		IMG_UINT32 uLength = 0;
		if (pHash->ppBucketTable[uIndex] == IMG_NULL)
		{
			uEmptyCount++;
		}
		for (pBucket=pHash->ppBucketTable[uIndex];
				pBucket != IMG_NULL;
				pBucket = pBucket->pNext)
		{
			uLength++;
		}
		uMaxLength = PRIVATE_MAX (uMaxLength, uLength);
	}

	PVR_TRACE(("hash table: uMinimumSize=%d  size=%d  count=%d",
			pHash->uMinimumSize, pHash->uSize, pHash->uCount));
	PVR_TRACE(("  empty=%d  max=%d", uEmptyCount, uMaxLength));
}
#endif