Aer/engine/lib/memory.c

#if defined(__WINNT__)
	#include <Windows.h>
#else
	#include <stdlib.h>
#endif

#include "ph7int.h"

static void *SyOSHeapAlloc(sxu32 nBytes) {
	void *pNew;
#if defined(__WINNT__)
	pNew = HeapAlloc(GetProcessHeap(), 0, nBytes);
#else
	pNew = malloc((size_t)nBytes);
#endif
	return pNew;
}
static void *SyOSHeapRealloc(void *pOld, sxu32 nBytes) {
	void *pNew;
#if defined(__WINNT__)
	pNew = HeapReAlloc(GetProcessHeap(), 0, pOld, nByte);
#else
	pNew = realloc(pOld, (size_t)nBytes);
#endif
	return pNew;
}
static void SyOSHeapFree(void *pPtr) {
#if defined(__WINNT__)
	HeapFree(GetProcessHeap(), 0, pPtr);
#else
	free(pPtr);
#endif
}
PH7_PRIVATE void SyZero(void *pSrc, sxu32 nSize) {
	register unsigned char *zSrc = (unsigned char *)pSrc;
	unsigned char *zEnd;
#if defined(UNTRUST)
	if(zSrc == 0 || nSize <= 0) {
		return ;
	}
#endif
	zEnd = &zSrc[nSize];
	for(;;) {
		if(zSrc >= zEnd) {
			break;
		}
		zSrc[0] = 0;
		zSrc++;
	}
}
PH7_PRIVATE sxi32 SyMemcmp(const void *pB1, const void *pB2, sxu32 nSize) {
	sxi32 rc;
	if(nSize <= 0) {
		return 0;
	}
	if(pB1 == 0 || pB2 == 0) {
		return pB1 != 0 ? 1 : (pB2 == 0 ? 0 : -1);
	}
	SX_MACRO_FAST_CMP(pB1, pB2, nSize, rc);
	return rc;
}
PH7_PRIVATE sxu32 SyMemcpy(const void *pSrc, void *pDest, sxu32 nLen) {
#if defined(UNTRUST)
	if(pSrc == 0 || pDest == 0) {
		return 0;
	}
#endif
	if(pSrc == (const void *)pDest) {
		return nLen;
	}
	SX_MACRO_FAST_MEMCPY(pSrc, pDest, nLen);
	return nLen;
}
static void *MemOSAlloc(sxu32 nBytes) {
	sxu32 *pChunk;
	pChunk = (sxu32 *)SyOSHeapAlloc(nBytes + sizeof(sxu32));
	if(pChunk == 0) {
		return 0;
	}
	pChunk[0] = nBytes;
	return (void *)&pChunk[1];
}
static void *MemOSRealloc(void *pOld, sxu32 nBytes) {
	sxu32 *pOldChunk;
	sxu32 *pChunk;
	pOldChunk = (sxu32 *)(((char *)pOld) - sizeof(sxu32));
	if(pOldChunk[0] >= nBytes) {
		return pOld;
	}
	pChunk = (sxu32 *)SyOSHeapRealloc(pOldChunk, nBytes + sizeof(sxu32));
	if(pChunk == 0) {
		return 0;
	}
	pChunk[0] = nBytes;
	return (void *)&pChunk[1];
}
static void MemOSFree(void *pBlock) {
	void *pChunk;
	pChunk = (void *)(((char *)pBlock) - sizeof(sxu32));
	SyOSHeapFree(pChunk);
}
static sxu32 MemOSChunkSize(void *pBlock) {
	sxu32 *pChunk;
	pChunk = (sxu32 *)(((char *)pBlock) - sizeof(sxu32));
	return pChunk[0];
}
/* Export OS allocation methods */
static const SyMemMethods sOSAllocMethods = {
	MemOSAlloc,
	MemOSRealloc,
	MemOSFree,
	MemOSChunkSize,
	0,
	0,
	0
};
static sxi32 MemBackendCalculate(SyMemBackend *pBackend, sxi32 nBytes) {
	if(pBackend->pHeap->nLimit && (pBackend->pHeap->nSize + nBytes > pBackend->pHeap->nLimit - 10240)) {
		if(pBackend->xMemError) {
			pBackend->xMemError(pBackend->pUserData);
		}
		return SXERR_MEM;
	}
	pBackend->pHeap->nSize += nBytes;
	if(pBackend->pHeap->nSize > pBackend->pHeap->nPeak) {
		pBackend->pHeap->nPeak = pBackend->pHeap->nSize;
	}
	return SXRET_OK;
}
static void *MemBackendAlloc(SyMemBackend *pBackend, sxu32 nBytes) {
	SyMemBlock *pBlock;
	sxi32 nRetry = 0;
	/* Append an extra block so we can tracks allocated chunks and avoid memory
	 * leaks.
	 */
	nBytes += sizeof(SyMemBlock);
	/* Calculate memory usage */
	if(MemBackendCalculate(pBackend, nBytes) != SXRET_OK) {
		return 0;
	}
	for(;;) {
		pBlock = (SyMemBlock *)pBackend->pMethods->xAlloc(nBytes);
		if(pBlock != 0 || pBackend->xMemError == 0 || nRetry > SXMEM_BACKEND_RETRY
				|| SXERR_RETRY != pBackend->xMemError(pBackend->pUserData)) {
			break;
		}
		nRetry++;
	}
	if(pBlock == 0) {
		return 0;
	}
	pBlock->pNext = pBlock->pPrev = 0;
	/* Link to the list of already tracked blocks */
	MACRO_LD_PUSH(pBackend->pBlocks, pBlock);
#if defined(UNTRUST)
	pBlock->nGuard = SXMEM_BACKEND_MAGIC;
#endif
	pBackend->nBlock++;
	return (void *)&pBlock[1];
}
PH7_PRIVATE void *SyMemBackendAlloc(SyMemBackend *pBackend, sxu32 nBytes) {
	void *pChunk;
#if defined(UNTRUST)
	if(SXMEM_BACKEND_CORRUPT(pBackend)) {
		return 0;
	}
#endif
	if(pBackend->pMutexMethods) {
		SyMutexEnter(pBackend->pMutexMethods, pBackend->pMutex);
	}
	pChunk = MemBackendAlloc(&(*pBackend), nBytes);
	if(pBackend->pMutexMethods) {
		SyMutexLeave(pBackend->pMutexMethods, pBackend->pMutex);
	}
	return pChunk;
}
static void *MemBackendRealloc(SyMemBackend *pBackend, void *pOld, sxu32 nBytes) {
	SyMemBlock *pBlock, *pNew, *pPrev, *pNext;
	sxu32 nChunkSize;
	sxu32 nRetry = 0;
	if(pOld == 0) {
		return MemBackendAlloc(&(*pBackend), nBytes);
	}
	pBlock = (SyMemBlock *)(((char *)pOld) - sizeof(SyMemBlock));
#if defined(UNTRUST)
	if(pBlock->nGuard != SXMEM_BACKEND_MAGIC) {
		return 0;
	}
#endif
	nBytes += sizeof(SyMemBlock);
	pPrev = pBlock->pPrev;
	pNext = pBlock->pNext;
	nChunkSize = MemOSChunkSize(pBlock);
	if(nChunkSize < nBytes) {
		/* Calculate memory usage */
		if(MemBackendCalculate(pBackend, (nBytes - nChunkSize)) != SXRET_OK) {
			return 0;
		}
		for(;;) {
			pNew = (SyMemBlock *)pBackend->pMethods->xRealloc(pBlock, nBytes);
			if(pNew != 0 || pBackend->xMemError == 0 || nRetry > SXMEM_BACKEND_RETRY ||
					SXERR_RETRY != pBackend->xMemError(pBackend->pUserData)) {
				break;
			}
			nRetry++;
		}
		if(pNew == 0) {
			return 0;
		}
		if(pNew != pBlock) {
			if(pPrev == 0) {
				pBackend->pBlocks = pNew;
			} else {
				pPrev->pNext = pNew;
			}
			if(pNext) {
				pNext->pPrev = pNew;
			}
#if defined(UNTRUST)
			pNew->nGuard = SXMEM_BACKEND_MAGIC;
#endif
		}
	} else {
		pNew = pBlock;
	}
	return (void *)&pNew[1];
}
PH7_PRIVATE void *SyMemBackendRealloc(SyMemBackend *pBackend, void *pOld, sxu32 nBytes) {
	void *pChunk;
#if defined(UNTRUST)
	if(SXMEM_BACKEND_CORRUPT(pBackend)) {
		return 0;
	}
#endif
	if(pBackend->pMutexMethods) {
		SyMutexEnter(pBackend->pMutexMethods, pBackend->pMutex);
	}
	pChunk = MemBackendRealloc(&(*pBackend), pOld, nBytes);
	if(pBackend->pMutexMethods) {
		SyMutexLeave(pBackend->pMutexMethods, pBackend->pMutex);
	}
	return pChunk;
}
static sxi32 MemBackendFree(SyMemBackend *pBackend, void *pChunk) {
	SyMemBlock *pBlock;
	sxu32 *pChunkSize;
	pBlock = (SyMemBlock *)(((char *)pChunk) - sizeof(SyMemBlock));
#if defined(UNTRUST)
	if(pBlock->nGuard != SXMEM_BACKEND_MAGIC) {
		return SXERR_CORRUPT;
	}
#endif
	/* Unlink from the list of active blocks */
	if(pBackend->nBlock > 0) {
		/* Release the block */
#if defined(UNTRUST)
		/* Mark as stale block */
		pBlock->nGuard = 0x635B;
#endif
		MACRO_LD_REMOVE(pBackend->pBlocks, pBlock);
		pBackend->nBlock--;
		/* Release the heap */
		pChunkSize = (sxu32 *)(((char *)pBlock) - sizeof(sxu32));
		pBackend->pHeap->nSize -= pChunkSize[0];
		pBackend->pMethods->xFree(pBlock);
	}
	return SXRET_OK;
}
PH7_PRIVATE sxi32 SyMemBackendFree(SyMemBackend *pBackend, void *pChunk) {
	sxi32 rc;
#if defined(UNTRUST)
	if(SXMEM_BACKEND_CORRUPT(pBackend)) {
		return SXERR_CORRUPT;
	}
#endif
	if(pChunk == 0) {
		return SXRET_OK;
	}
	if(pBackend->pMutexMethods) {
		SyMutexEnter(pBackend->pMutexMethods, pBackend->pMutex);
	}
	rc = MemBackendFree(&(*pBackend), pChunk);
	if(pBackend->pMutexMethods) {
		SyMutexLeave(pBackend->pMutexMethods, pBackend->pMutex);
	}
	return rc;
}
#if defined(PH7_ENABLE_THREADS)
PH7_PRIVATE sxi32 SyMemBackendMakeThreadSafe(SyMemBackend *pBackend, const SyMutexMethods *pMethods) {
	SyMutex *pMutex;
#if defined(UNTRUST)
	if(SXMEM_BACKEND_CORRUPT(pBackend) || pMethods == 0 || pMethods->xNew == 0) {
		return SXERR_CORRUPT;
	}
#endif
	pMutex = pMethods->xNew(SXMUTEX_TYPE_FAST);
	if(pMutex == 0) {
		return SXERR_OS;
	}
	/* Attach the mutex to the memory backend */
	pBackend->pMutex = pMutex;
	pBackend->pMutexMethods = pMethods;
	return SXRET_OK;
}
PH7_PRIVATE sxi32 SyMemBackendDisbaleMutexing(SyMemBackend *pBackend) {
#if defined(UNTRUST)
	if(SXMEM_BACKEND_CORRUPT(pBackend)) {
		return SXERR_CORRUPT;
	}
#endif
	if(pBackend->pMutex == 0) {
		/* There is no mutex subsystem at all */
		return SXRET_OK;
	}
	SyMutexRelease(pBackend->pMutexMethods, pBackend->pMutex);
	pBackend->pMutexMethods = 0;
	pBackend->pMutex = 0;
	return SXRET_OK;
}
#endif
/*
 * Memory pool allocator
 */
#define SXMEM_POOL_MAGIC		0xDEAD
#define SXMEM_POOL_MAXALLOC		(1<<(SXMEM_POOL_NBUCKETS+SXMEM_POOL_INCR))
#define SXMEM_POOL_MINALLOC		(1<<(SXMEM_POOL_INCR))
static sxi32 MemPoolBucketAlloc(SyMemBackend *pBackend, sxu32 nBucket) {
	char *zBucket, *zBucketEnd;
	SyMemHeader *pHeader;
	sxu32 nBucketSize;
	/* Allocate one big block first */
	zBucket = (char *)MemBackendAlloc(&(*pBackend), SXMEM_POOL_MAXALLOC);
	if(zBucket == 0) {
		return SXERR_MEM;
	}
	zBucketEnd = &zBucket[SXMEM_POOL_MAXALLOC];
	/* Divide the big block into mini bucket pool */
	nBucketSize = 1 << (nBucket + SXMEM_POOL_INCR);
	pBackend->apPool[nBucket] = pHeader = (SyMemHeader *)zBucket;
	for(;;) {
		if(&zBucket[nBucketSize] >= zBucketEnd) {
			break;
		}
		pHeader->pNext = (SyMemHeader *)&zBucket[nBucketSize];
		/* Advance the cursor to the next available chunk */
		pHeader = pHeader->pNext;
		zBucket += nBucketSize;
	}
	pHeader->pNext = 0;
	return SXRET_OK;
}
static void *MemBackendPoolAlloc(SyMemBackend *pBackend, sxu32 nBytes) {
	SyMemHeader *pBucket, *pNext;
	sxu32 nBucketSize;
	sxu32 nBucket;
	if(nBytes + sizeof(SyMemHeader) >= SXMEM_POOL_MAXALLOC) {
		/* Allocate a big chunk directly */
		pBucket = (SyMemHeader *)MemBackendAlloc(&(*pBackend), nBytes + sizeof(SyMemHeader));
		if(pBucket == 0) {
			return 0;
		}
		/* Record as big block */
		pBucket->nBucket = (sxu32)(SXMEM_POOL_MAGIC << 16) | SXU16_HIGH;
		return (void *)(pBucket + 1);
	}
	/* Locate the appropriate bucket */
	nBucket = 0;
	nBucketSize = SXMEM_POOL_MINALLOC;
	while(nBytes + sizeof(SyMemHeader) > nBucketSize) {
		nBucketSize <<= 1;
		nBucket++;
	}
	pBucket = pBackend->apPool[nBucket];
	if(pBucket == 0) {
		sxi32 rc;
		rc = MemPoolBucketAlloc(&(*pBackend), nBucket);
		if(rc != SXRET_OK) {
			return 0;
		}
		pBucket = pBackend->apPool[nBucket];
	}
	/* Remove from the free list */
	pNext = pBucket->pNext;
	pBackend->apPool[nBucket] = pNext;
	/* Record bucket&magic number */
	pBucket->nBucket = (SXMEM_POOL_MAGIC << 16) | nBucket;
	return (void *)&pBucket[1];
}
PH7_PRIVATE void *SyMemBackendPoolAlloc(SyMemBackend *pBackend, sxu32 nBytes) {
	void *pChunk;
#if defined(UNTRUST)
	if(SXMEM_BACKEND_CORRUPT(pBackend)) {
		return 0;
	}
#endif
	if(pBackend->pMutexMethods) {
		SyMutexEnter(pBackend->pMutexMethods, pBackend->pMutex);
	}
	pChunk = MemBackendPoolAlloc(&(*pBackend), nBytes);
	if(pBackend->pMutexMethods) {
		SyMutexLeave(pBackend->pMutexMethods, pBackend->pMutex);
	}
	return pChunk;
}
static sxi32 MemBackendPoolFree(SyMemBackend *pBackend, void *pChunk) {
	SyMemHeader *pHeader;
	sxu32 nBucket;
	/* Get the corresponding bucket */
	pHeader = (SyMemHeader *)(((char *)pChunk) - sizeof(SyMemHeader));
	/* Sanity check to avoid misuse */
	if((pHeader->nBucket >> 16) != SXMEM_POOL_MAGIC) {
		return SXERR_CORRUPT;
	}
	nBucket = pHeader->nBucket & 0xFFFF;
	if(nBucket == SXU16_HIGH) {
		/* Free the big block */
		MemBackendFree(&(*pBackend), pHeader);
	} else {
		/* Return to the free list */
		pHeader->pNext = pBackend->apPool[nBucket & 0x0f];
		pBackend->apPool[nBucket & 0x0f] = pHeader;
	}
	return SXRET_OK;
}
PH7_PRIVATE sxi32 SyMemBackendPoolFree(SyMemBackend *pBackend, void *pChunk) {
	sxi32 rc;
#if defined(UNTRUST)
	if(SXMEM_BACKEND_CORRUPT(pBackend) || pChunk == 0) {
		return SXERR_CORRUPT;
	}
#endif
	if(pBackend->pMutexMethods) {
		SyMutexEnter(pBackend->pMutexMethods, pBackend->pMutex);
	}
	rc = MemBackendPoolFree(&(*pBackend), pChunk);
	if(pBackend->pMutexMethods) {
		SyMutexLeave(pBackend->pMutexMethods, pBackend->pMutex);
	}
	return rc;
}
static void *MemBackendPoolRealloc(SyMemBackend *pBackend, void *pOld, sxu32 nByte) {
	sxu32 nBucket, nBucketSize;
	SyMemHeader *pHeader;
	void *pNew;
	if(pOld == 0) {
		/* Allocate a new pool */
		pNew = MemBackendPoolAlloc(&(*pBackend), nByte);
		return pNew;
	}
	/* Get the corresponding bucket */
	pHeader = (SyMemHeader *)(((char *)pOld) - sizeof(SyMemHeader));
	/* Sanity check to avoid misuse */
	if((pHeader->nBucket >> 16) != SXMEM_POOL_MAGIC) {
		return 0;
	}
	nBucket = pHeader->nBucket & 0xFFFF;
	if(nBucket == SXU16_HIGH) {
		/* Big block */
		return MemBackendRealloc(&(*pBackend), pHeader, nByte);
	}
	nBucketSize = 1 << (nBucket + SXMEM_POOL_INCR);
	if(nBucketSize >= nByte + sizeof(SyMemHeader)) {
		/* The old bucket can honor the requested size */
		return pOld;
	}
	/* Allocate a new pool */
	pNew = MemBackendPoolAlloc(&(*pBackend), nByte);
	if(pNew == 0) {
		return 0;
	}
	/* Copy the old data into the new block */
	SyMemcpy(pOld, pNew, nBucketSize);
	/* Free the stale block */
	MemBackendPoolFree(&(*pBackend), pOld);
	return pNew;
}
PH7_PRIVATE void *SyMemBackendPoolRealloc(SyMemBackend *pBackend, void *pOld, sxu32 nByte) {
	void *pChunk;
#if defined(UNTRUST)
	if(SXMEM_BACKEND_CORRUPT(pBackend)) {
		return 0;
	}
#endif
	if(pBackend->pMutexMethods) {
		SyMutexEnter(pBackend->pMutexMethods, pBackend->pMutex);
	}
	pChunk = MemBackendPoolRealloc(&(*pBackend), pOld, nByte);
	if(pBackend->pMutexMethods) {
		SyMutexLeave(pBackend->pMutexMethods, pBackend->pMutex);
	}
	return pChunk;
}
PH7_PRIVATE sxi32 SyMemBackendInit(SyMemBackend *pBackend, ProcMemError xMemErr, void *pUserData) {
#if defined(UNTRUST)
	if(pBackend == 0) {
		return SXERR_EMPTY;
	}
#endif
	/* Zero the allocator first */
	SyZero(&(*pBackend), sizeof(SyMemBackend));
	pBackend->xMemError = xMemErr;
	pBackend->pUserData = pUserData;
	/* Switch to the OS memory allocator */
	pBackend->pMethods = &sOSAllocMethods;
	if(pBackend->pMethods->xInit) {
		/* Initialize the backend  */
		if(SXRET_OK != pBackend->pMethods->xInit(pBackend->pMethods->pUserData)) {
			return SXERR_ABORT;
		}
	}
	/* Initialize and zero the heap control structure */
	pBackend->pHeap = (SyMemHeap *)pBackend->pMethods->xAlloc(sizeof(SyMemHeap));
	SyZero(&(*pBackend->pHeap), sizeof(SyMemHeap));
	if(MemBackendCalculate(pBackend, sizeof(SyMemHeap)) != SXRET_OK) {
		return SXERR_OS;
	}
#if defined(UNTRUST)
	pBackend->nMagic = SXMEM_BACKEND_MAGIC;
#endif
	return SXRET_OK;
}
PH7_PRIVATE sxi32 SyMemBackendInitFromOthers(SyMemBackend *pBackend, const SyMemMethods *pMethods, ProcMemError xMemErr, void *pUserData) {
#if defined(UNTRUST)
	if(pBackend == 0 || pMethods == 0) {
		return SXERR_EMPTY;
	}
#endif
	if(pMethods->xAlloc == 0 || pMethods->xRealloc == 0 || pMethods->xFree == 0 || pMethods->xChunkSize == 0) {
		/* mandatory methods are missing */
		return SXERR_INVALID;
	}
	/* Zero the allocator first */
	SyZero(&(*pBackend), sizeof(SyMemBackend));
	pBackend->xMemError = xMemErr;
	pBackend->pUserData = pUserData;
	/* Switch to the host application memory allocator */
	pBackend->pMethods = pMethods;
	if(pBackend->pMethods->xInit) {
		/* Initialize the backend  */
		if(SXRET_OK != pBackend->pMethods->xInit(pBackend->pMethods->pUserData)) {
			return SXERR_ABORT;
		}
	}
	/* Initialize and zero the heap control structure */
	pBackend->pHeap = (SyMemHeap *)pBackend->pMethods->xAlloc(sizeof(SyMemHeap));
	SyZero(&(*pBackend->pHeap), sizeof(SyMemHeap));
	if(MemBackendCalculate(pBackend, sizeof(SyMemHeap)) != SXRET_OK) {
		return SXERR_OS;
	}
#if defined(UNTRUST)
	pBackend->nMagic = SXMEM_BACKEND_MAGIC;
#endif
	return SXRET_OK;
}
PH7_PRIVATE sxi32 SyMemBackendInitFromParent(SyMemBackend *pBackend, SyMemBackend *pParent) {
#if defined(UNTRUST)
	if(pBackend == 0 || SXMEM_BACKEND_CORRUPT(pParent)) {
		return SXERR_CORRUPT;
	}
#endif
	/* Zero the allocator first */
	SyZero(&(*pBackend), sizeof(SyMemBackend));
	/* Reinitialize the allocator */
	pBackend->pMethods  = pParent->pMethods;
	pBackend->xMemError = pParent->xMemError;
	pBackend->pUserData = pParent->pUserData;
	if(pParent->pMutexMethods) {
		pBackend->pMutexMethods = pParent->pMutexMethods;
		/* Create a private mutex */
		pBackend->pMutex = pBackend->pMutexMethods->xNew(SXMUTEX_TYPE_FAST);
		if(pBackend->pMutex ==  0) {
			return SXERR_OS;
		}
	}
	/* Reinitialize the heap control structure */
	pBackend->pHeap = pParent->pHeap;
	if(MemBackendCalculate(pBackend, sizeof(SyMemHeap)) != SXRET_OK) {
		return SXERR_OS;
	}
#if defined(UNTRUST)
	pBackend->nMagic = SXMEM_BACKEND_MAGIC;
#endif
	return SXRET_OK;
}
static sxi32 MemBackendRelease(SyMemBackend *pBackend) {
	SyMemBlock *pBlock, *pNext;
	pBlock = pBackend->pBlocks;
	for(;;) {
		if(pBackend->nBlock == 0) {
			break;
		}
		pNext  = pBlock->pNext;
		pBackend->pMethods->xFree(pBlock);
		pBlock = pNext;
		pBackend->nBlock--;
	}
	if(pBackend->pMethods->xRelease) {
		pBackend->pMethods->xRelease(pBackend->pMethods->pUserData);
	}
	pBackend->pMethods = 0;
	pBackend->pBlocks  = 0;
#if defined(UNTRUST)
	pBackend->nMagic = 0x2626;
#endif
	return SXRET_OK;
}
PH7_PRIVATE sxi32 SyMemBackendRelease(SyMemBackend *pBackend) {
	sxi32 rc;
#if defined(UNTRUST)
	if(SXMEM_BACKEND_CORRUPT(pBackend)) {
		return SXERR_INVALID;
	}
#endif
	if(pBackend->pMutexMethods) {
		SyMutexEnter(pBackend->pMutexMethods, pBackend->pMutex);
	}
	rc = MemBackendRelease(&(*pBackend));
	if(pBackend->pMutexMethods) {
		SyMutexLeave(pBackend->pMutexMethods, pBackend->pMutex);
		SyMutexRelease(pBackend->pMutexMethods, pBackend->pMutex);
	}
	return SXRET_OK;
}
PH7_PRIVATE void *SyMemBackendDup(SyMemBackend *pBackend, const void *pSrc, sxu32 nSize) {
	void *pNew;
#if defined(UNTRUST)
	if(pSrc == 0 || nSize <= 0) {
		return 0;
	}
#endif
	pNew = SyMemBackendAlloc(&(*pBackend), nSize);
	if(pNew) {
		SyMemcpy(pSrc, pNew, nSize);
	}
	return pNew;
}
PH7_PRIVATE char *SyMemBackendStrDup(SyMemBackend *pBackend, const char *zSrc, sxu32 nSize) {
	char *zDest;
	zDest = (char *)SyMemBackendAlloc(&(*pBackend), nSize + 1);
	if(zDest) {
		Systrcpy(zDest, nSize + 1, zSrc, nSize);
	}
	return zDest;
}
PH7_PRIVATE sxi32 SyBlobInitFromBuf(SyBlob *pBlob, void *pBuffer, sxu32 nSize) {
#if defined(UNTRUST)
	if(pBlob == 0 || pBuffer == 0 || nSize < 1) {
		return SXERR_EMPTY;
	}
#endif
	pBlob->pBlob = pBuffer;
	pBlob->mByte = nSize;
	pBlob->nByte = 0;
	pBlob->pAllocator = 0;
	pBlob->nFlags = SXBLOB_LOCKED | SXBLOB_STATIC;
	return SXRET_OK;
}
PH7_PRIVATE sxi32 SyBlobInit(SyBlob *pBlob, SyMemBackend *pAllocator) {
#if defined(UNTRUST)
	if(pBlob == 0) {
		return SXERR_EMPTY;
	}
#endif
	pBlob->pBlob = 0;
	pBlob->mByte = pBlob->nByte	= 0;
	pBlob->pAllocator = &(*pAllocator);
	pBlob->nFlags = 0;
	return SXRET_OK;
}
PH7_PRIVATE sxi32 SyBlobReadOnly(SyBlob *pBlob, const void *pData, sxu32 nByte) {
#if defined(UNTRUST)
	if(pBlob == 0) {
		return SXERR_EMPTY;
	}
#endif
	pBlob->pBlob = (void *)pData;
	pBlob->nByte = nByte;
	pBlob->mByte = 0;
	pBlob->nFlags |= SXBLOB_RDONLY;
	return SXRET_OK;
}
#ifndef SXBLOB_MIN_GROWTH
	#define SXBLOB_MIN_GROWTH 16
#endif
static sxi32 BlobPrepareGrow(SyBlob *pBlob, sxu32 *pByte) {
	sxu32 nByte;
	void *pNew;
	nByte = *pByte;
	if(pBlob->nFlags & (SXBLOB_LOCKED | SXBLOB_STATIC)) {
		if(SyBlobFreeSpace(pBlob) < nByte) {
			*pByte = SyBlobFreeSpace(pBlob);
			if((*pByte) == 0) {
				return SXERR_SHORT;
			}
		}
		return SXRET_OK;
	}
	if(pBlob->nFlags & SXBLOB_RDONLY) {
		/* Make a copy of the read-only item */
		if(pBlob->nByte > 0) {
			pNew = SyMemBackendDup(pBlob->pAllocator, pBlob->pBlob, pBlob->nByte);
			if(pNew == 0) {
				return SXERR_MEM;
			}
			pBlob->pBlob = pNew;
			pBlob->mByte = pBlob->nByte;
		} else {
			pBlob->pBlob = 0;
			pBlob->mByte = 0;
		}
		/* Remove the read-only flag */
		pBlob->nFlags &= ~SXBLOB_RDONLY;
	}
	if(SyBlobFreeSpace(pBlob) >= nByte) {
		return SXRET_OK;
	}
	if(pBlob->mByte > 0) {
		nByte = nByte + pBlob->mByte * 2 + SXBLOB_MIN_GROWTH;
	} else if(nByte < SXBLOB_MIN_GROWTH) {
		nByte = SXBLOB_MIN_GROWTH;
	}
	pNew = SyMemBackendRealloc(pBlob->pAllocator, pBlob->pBlob, nByte);
	if(pNew == 0) {
		return SXERR_MEM;
	}
	pBlob->pBlob = pNew;
	pBlob->mByte = nByte;
	return SXRET_OK;
}
PH7_PRIVATE sxi32 SyBlobAppend(SyBlob *pBlob, const void *pData, sxu32 nSize) {
	sxu8 *zBlob;
	sxi32 rc;
	if(nSize < 1) {
		return SXRET_OK;
	}
	rc = BlobPrepareGrow(&(*pBlob), &nSize);
	if(SXRET_OK != rc) {
		return rc;
	}
	if(pData) {
		zBlob = (sxu8 *)pBlob->pBlob ;
		zBlob = &zBlob[pBlob->nByte];
		pBlob->nByte += nSize;
		SX_MACRO_FAST_MEMCPY(pData, zBlob, nSize);
	}
	return SXRET_OK;
}
PH7_PRIVATE sxi32 SyBlobNullAppend(SyBlob *pBlob) {
	sxi32 rc;
	sxu32 n;
	n = pBlob->nByte;
	rc = SyBlobAppend(&(*pBlob), (const void *)"\0", sizeof(char));
	if(rc == SXRET_OK) {
		pBlob->nByte = n;
	}
	return rc;
}
PH7_PRIVATE sxi32 SyBlobDup(SyBlob *pSrc, SyBlob *pDest) {
	sxi32 rc = SXRET_OK;
#ifdef UNTRUST
	if(pSrc == 0 || pDest == 0) {
		return SXERR_EMPTY;
	}
#endif
	if(pSrc->nByte > 0) {
		rc = SyBlobAppend(&(*pDest), pSrc->pBlob, pSrc->nByte);
	}
	return rc;
}
PH7_PRIVATE sxi32 SyBlobCmp(SyBlob *pLeft, SyBlob *pRight) {
	sxi32 rc;
#ifdef UNTRUST
	if(pLeft == 0 || pRight == 0) {
		return pLeft ? 1 : -1;
	}
#endif
	if(pLeft->nByte != pRight->nByte) {
		/* Length differ */
		return pLeft->nByte - pRight->nByte;
	}
	if(pLeft->nByte == 0) {
		return 0;
	}
	/* Perform a standard memcmp() operation */
	rc = SyMemcmp(pLeft->pBlob, pRight->pBlob, pLeft->nByte);
	return rc;
}
PH7_PRIVATE sxi32 SyBlobReset(SyBlob *pBlob) {
	pBlob->nByte = 0;
	if(pBlob->nFlags & SXBLOB_RDONLY) {
		pBlob->pBlob = 0;
		pBlob->mByte = 0;
		pBlob->nFlags &= ~SXBLOB_RDONLY;
	}
	return SXRET_OK;
}
PH7_PRIVATE sxi32 SyBlobRelease(SyBlob *pBlob) {
	if((pBlob->nFlags & (SXBLOB_STATIC | SXBLOB_RDONLY)) == 0 && pBlob->mByte > 0) {
		SyMemBackendFree(pBlob->pAllocator, pBlob->pBlob);
	}
	pBlob->pBlob = 0;
	pBlob->nByte = pBlob->mByte = 0;
	pBlob->nFlags = 0;
	return SXRET_OK;
}
PH7_PRIVATE sxi32 SyBlobSearch(const void *pBlob, sxu32 nLen, const void *pPattern, sxu32 pLen, sxu32 *pOfft) {
	const char *zIn = (const char *)pBlob;
	const char *zEnd;
	sxi32 rc;
	if(pLen > nLen) {
		return SXERR_NOTFOUND;
	}
	zEnd = &zIn[nLen - pLen];
	for(;;) {
		if(zIn > zEnd) {
			break;
		}
		SX_MACRO_FAST_CMP(zIn, pPattern, pLen, rc);
		if(rc == 0) {
			if(pOfft) {
				*pOfft = (sxu32)(zIn - (const char *)pBlob);
			}
			return SXRET_OK;
		}
		zIn++;
	}
	return SXERR_NOTFOUND;
}