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Diffstat (limited to 'win32/vmem.h')
| -rw-r--r-- | win32/vmem.h | 703 |
1 files changed, 703 insertions, 0 deletions
diff --git a/win32/vmem.h b/win32/vmem.h new file mode 100644 index 0000000000..cf3f502ca0 --- /dev/null +++ b/win32/vmem.h @@ -0,0 +1,703 @@ +/* vmem.h + * + * (c) 1999 Microsoft Corporation. All rights reserved. + * Portions (c) 1999 ActiveState Tool Corp, http://www.ActiveState.com/ + * + * You may distribute under the terms of either the GNU General Public + * License or the Artistic License, as specified in the README file. + * + * + * Knuth's boundary tag algorithm Vol #1, Page 440. + * + * Each block in the heap has tag words before and after it, + * TAG + * block + * TAG + * The size is stored in these tags as a long word, and includes the 8 bytes + * of overhead that the boundary tags consume. Blocks are allocated on long + * word boundaries, so the size is always multiples of long words. When the + * block is allocated, bit 0, (the tag bit), of the size is set to 1. When + * a block is freed, it is merged with adjacent free blocks, and the tag bit + * is set to 0. + * + * A linked list is used to manage the free list. The first two long words of + * the block contain double links. These links are only valid when the block + * is freed, therefore space needs to be reserved for them. Thus, the minimum + * block size (not counting the tags) is 8 bytes. + * + * Since memory allocation may occur on a single threaded, explict locks are + * provided. + * + */ + +#ifndef ___VMEM_H_INC___ +#define ___VMEM_H_INC___ + +const long lAllocStart = 0x00010000; /* start at 64K */ +const long minBlockSize = sizeof(void*)*2; +const long sizeofTag = sizeof(long); +const long blockOverhead = sizeofTag*2; +const long minAllocSize = minBlockSize+blockOverhead; + +typedef BYTE* PBLOCK; /* pointer to a memory block */ + +/* + * Macros for accessing hidden fields in a memory block: + * + * SIZE size of this block (tag bit 0 is 1 if block is allocated) + * PSIZE size of previous physical block + */ + +#define SIZE(block) (*(ULONG*)(((PBLOCK)(block))-sizeofTag)) +#define PSIZE(block) (*(ULONG*)(((PBLOCK)(block))-(sizeofTag*2))) +inline void SetTags(PBLOCK block, long size) +{ + SIZE(block) = size; + PSIZE(block+(size&~1)) = size; +} + +/* + * Free list pointers + * PREV pointer to previous block + * NEXT pointer to next block + */ + +#define PREV(block) (*(PBLOCK*)(block)) +#define NEXT(block) (*(PBLOCK*)((block)+sizeof(PBLOCK))) +inline void SetLink(PBLOCK block, PBLOCK prev, PBLOCK next) +{ + PREV(block) = prev; + NEXT(block) = next; +} +inline void Unlink(PBLOCK p) +{ + PBLOCK next = NEXT(p); + PBLOCK prev = PREV(p); + NEXT(prev) = next; + PREV(next) = prev; +} +inline void AddToFreeList(PBLOCK block, PBLOCK pInList) +{ + PBLOCK next = NEXT(pInList); + NEXT(pInList) = block; + SetLink(block, pInList, next); + PREV(next) = block; +} + + +/* Macro for rounding up to the next sizeof(long) */ +#define ROUND_UP(n) (((ULONG)(n)+sizeof(long)-1)&~(sizeof(long)-1)) +#define ROUND_UP64K(n) (((ULONG)(n)+0x10000-1)&~(0x10000-1)) +#define ROUND_DOWN(n) ((ULONG)(n)&~(sizeof(long)-1)) + +/* + * HeapRec - a list of all non-contiguous heap areas + * + * Each record in this array contains information about a non-contiguous heap area. + */ + +const int maxHeaps = 64; +const long lAllocMax = 0x80000000; /* max size of allocation */ + +typedef struct _HeapRec +{ + PBLOCK base; /* base of heap area */ + ULONG len; /* size of heap area */ +} HeapRec; + + +class VMem +{ +public: + VMem(); + ~VMem(); + virtual void* Malloc(size_t size); + virtual void* Realloc(void* pMem, size_t size); + virtual void Free(void* pMem); + virtual void GetLock(void); + virtual void FreeLock(void); + virtual int IsLocked(void); + virtual long Release(void); + virtual long AddRef(void); + + inline BOOL CreateOk(void) + { + return m_hHeap != NULL; + }; + + void ReInit(void); + +protected: + void Init(void); + int Getmem(size_t size); + int HeapAdd(void* ptr, size_t size); + void* Expand(void* block, size_t size); + void WalkHeap(void); + + HANDLE m_hHeap; // memory heap for this script + char m_FreeDummy[minAllocSize]; // dummy free block + PBLOCK m_pFreeList; // pointer to first block on free list + PBLOCK m_pRover; // roving pointer into the free list + HeapRec m_heaps[maxHeaps]; // list of all non-contiguous heap areas + int m_nHeaps; // no. of heaps in m_heaps + long m_lAllocSize; // current alloc size + long m_lRefCount; // number of current users + CRITICAL_SECTION m_cs; // access lock +}; + +// #define _DEBUG_MEM +#ifdef _DEBUG_MEM +#define ASSERT(f) if(!(f)) DebugBreak(); + +inline void MEMODS(char *str) +{ + OutputDebugString(str); + OutputDebugString("\n"); +} + +inline void MEMODSlx(char *str, long x) +{ + char szBuffer[512]; + sprintf(szBuffer, "%s %lx\n", str, x); + OutputDebugString(szBuffer); +} + +#define WALKHEAP() WalkHeap() +#define WALKHEAPTRACE() m_pRover = NULL; WalkHeap() + +#else + +#define ASSERT(f) +#define MEMODS(x) +#define MEMODSlx(x, y) +#define WALKHEAP() +#define WALKHEAPTRACE() + +#endif + + +VMem::VMem() +{ + m_lRefCount = 1; + BOOL bRet = (NULL != (m_hHeap = HeapCreate(HEAP_NO_SERIALIZE, + lAllocStart, /* initial size of heap */ + 0))); /* no upper limit on size of heap */ + ASSERT(bRet); + + InitializeCriticalSection(&m_cs); + + Init(); +} + +VMem::~VMem(void) +{ + ASSERT(HeapValidate(m_hHeap, HEAP_NO_SERIALIZE, NULL)); + WALKHEAPTRACE(); + DeleteCriticalSection(&m_cs); + BOOL bRet = HeapDestroy(m_hHeap); + ASSERT(bRet); +} + +void VMem::ReInit(void) +{ + for(int index = 0; index < m_nHeaps; ++index) + HeapFree(m_hHeap, HEAP_NO_SERIALIZE, m_heaps[index].base); + + Init(); +} + +void VMem::Init(void) +{ /* + * Initialize the free list by placing a dummy zero-length block on it. + * Set the number of non-contiguous heaps to zero. + */ + m_pFreeList = m_pRover = (PBLOCK)(&m_FreeDummy[minBlockSize]); + PSIZE(m_pFreeList) = SIZE(m_pFreeList) = 0; + PREV(m_pFreeList) = NEXT(m_pFreeList) = m_pFreeList; + + m_nHeaps = 0; + m_lAllocSize = lAllocStart; +} + +void* VMem::Malloc(size_t size) +{ + WALKHEAP(); + + /* + * Adjust the real size of the block to be a multiple of sizeof(long), and add + * the overhead for the boundary tags. Disallow negative or zero sizes. + */ + size_t realsize = (size < blockOverhead) ? minAllocSize : (size_t)ROUND_UP(size) + minBlockSize; + if((int)realsize < minAllocSize || size == 0) + return NULL; + + /* + * Start searching the free list at the rover. If we arrive back at rover without + * finding anything, allocate some memory from the heap and try again. + */ + PBLOCK ptr = m_pRover; /* start searching at rover */ + int loops = 2; /* allow two times through the loop */ + for(;;) { + size_t lsize = SIZE(ptr); + ASSERT((lsize&1)==0); + /* is block big enough? */ + if(lsize >= realsize) { + /* if the remainder is too small, don't bother splitting the block. */ + size_t rem = lsize - realsize; + if(rem < minAllocSize) { + if(m_pRover == ptr) + m_pRover = NEXT(ptr); + + /* Unlink the block from the free list. */ + Unlink(ptr); + } + else { + /* + * split the block + * The remainder is big enough to split off into a new block. + * Use the end of the block, resize the beginning of the block + * no need to change the free list. + */ + SetTags(ptr, rem); + ptr += SIZE(ptr); + lsize = realsize; + } + /* Set the boundary tags to mark it as allocated. */ + SetTags(ptr, lsize | 1); + return ((void *)ptr); + } + + /* + * This block was unsuitable. If we've gone through this list once already without + * finding anything, allocate some new memory from the heap and try again. + */ + ptr = NEXT(ptr); + if(ptr == m_pRover) { + if(!(loops-- && Getmem(realsize))) { + return NULL; + } + ptr = m_pRover; + } + } +} + +void* VMem::Realloc(void* block, size_t size) +{ + WALKHEAP(); + + /* if size is zero, free the block. */ + if(size == 0) { + Free(block); + return (NULL); + } + + /* if block pointer is NULL, do a Malloc(). */ + if(block == NULL) + return Malloc(size); + + /* + * Grow or shrink the block in place. + * if the block grows then the next block will be used if free + */ + if(Expand(block, size) != NULL) + return block; + + /* + * adjust the real size of the block to be a multiple of sizeof(long), and add the + * overhead for the boundary tags. Disallow negative or zero sizes. + */ + size_t realsize = (size < blockOverhead) ? minAllocSize : (size_t)ROUND_UP(size) + minBlockSize; + if((int)realsize < minAllocSize) + return NULL; + + /* + * see if the previous block is free, and is it big enough to cover the new size + * if merged with the current block. + */ + PBLOCK ptr = (PBLOCK)block; + size_t cursize = SIZE(ptr) & ~1; + size_t psize = PSIZE(ptr); + if((psize&1) == 0 && (psize + cursize) >= realsize) { + PBLOCK prev = ptr - psize; + if(m_pRover == prev) + m_pRover = NEXT(prev); + + /* Unlink the next block from the free list. */ + Unlink(prev); + + /* Copy contents of old block to new location, make it the current block. */ + memmove(prev, ptr, cursize); + cursize += psize; /* combine sizes */ + ptr = prev; + + size_t rem = cursize - realsize; + if(rem >= minAllocSize) { + /* + * The remainder is big enough to be a new block. Set boundary + * tags for the resized block and the new block. + */ + prev = ptr + realsize; + /* + * add the new block to the free list. + * next block cannot be free + */ + SetTags(prev, rem); + AddToFreeList(prev, m_pFreeList); + cursize = realsize; + } + /* Set the boundary tags to mark it as allocated. */ + SetTags(ptr, cursize | 1); + return ((void *)ptr); + } + + /* Allocate a new block, copy the old to the new, and free the old. */ + if((ptr = (PBLOCK)Malloc(size)) != NULL) { + memmove(ptr, block, cursize-minBlockSize); + Free(block); + } + return ((void *)ptr); +} + +void VMem::Free(void* p) +{ + WALKHEAP(); + + /* Ignore null pointer. */ + if(p == NULL) + return; + + PBLOCK ptr = (PBLOCK)p; + + /* Check for attempt to free a block that's already free. */ + size_t size = SIZE(ptr); + if((size&1) == 0) { + MEMODSlx("Attempt to free previously freed block", (long)p); + return; + } + size &= ~1; /* remove allocated tag */ + + /* if previous block is free, add this block to it. */ + int linked = FALSE; + size_t psize = PSIZE(ptr); + if((psize&1) == 0) { + ptr -= psize; /* point to previous block */ + size += psize; /* merge the sizes of the two blocks */ + linked = TRUE; /* it's already on the free list */ + } + + /* if the next physical block is free, merge it with this block. */ + PBLOCK next = ptr + size; /* point to next physical block */ + size_t nsize = SIZE(next); + if((nsize&1) == 0) { + /* block is free move rover if needed */ + if(m_pRover == next) + m_pRover = NEXT(next); + + /* unlink the next block from the free list. */ + Unlink(next); + + /* merge the sizes of this block and the next block. */ + size += nsize; + } + + /* Set the boundary tags for the block; */ + SetTags(ptr, size); + + /* Link the block to the head of the free list. */ + if(!linked) { + AddToFreeList(ptr, m_pFreeList); + } +} + +void VMem::GetLock(void) +{ + EnterCriticalSection(&m_cs); +} + +void VMem::FreeLock(void) +{ + LeaveCriticalSection(&m_cs); +} + +int VMem::IsLocked(void) +{ + BOOL bAccessed = TryEnterCriticalSection(&m_cs); + if(bAccessed) { + LeaveCriticalSection(&m_cs); + } + return !bAccessed; +} + + +long VMem::Release(void) +{ + long lCount = InterlockedDecrement(&m_lRefCount); + if(!lCount) + delete this; + return lCount; +} + +long VMem::AddRef(void) +{ + long lCount = InterlockedIncrement(&m_lRefCount); + return lCount; +} + + +int VMem::Getmem(size_t requestSize) +{ /* returns -1 is successful 0 if not */ + void *ptr; + + /* Round up size to next multiple of 64K. */ + size_t size = (size_t)ROUND_UP64K(requestSize); + + /* + * if the size requested is smaller than our current allocation size + * adjust up + */ + if(size < (unsigned long)m_lAllocSize) + size = m_lAllocSize; + + /* Update the size to allocate on the next request */ + if(m_lAllocSize != lAllocMax) + m_lAllocSize <<= 1; + + if(m_nHeaps != 0) { + /* Expand the last allocated heap */ + ptr = HeapReAlloc(m_hHeap, HEAP_REALLOC_IN_PLACE_ONLY|HEAP_ZERO_MEMORY|HEAP_NO_SERIALIZE, + m_heaps[m_nHeaps-1].base, + m_heaps[m_nHeaps-1].len + size); + if(ptr != 0) { + HeapAdd(((char*)ptr) + m_heaps[m_nHeaps-1].len, size); + return -1; + } + } + + /* + * if we didn't expand a block to cover the requested size + * allocate a new Heap + * the size of this block must include the additional dummy tags at either end + * the above ROUND_UP64K may not have added any memory to include this. + */ + if(size == requestSize) + size = (size_t)ROUND_UP64K(requestSize+(sizeofTag*2)); + + ptr = HeapAlloc(m_hHeap, HEAP_ZERO_MEMORY|HEAP_NO_SERIALIZE, size); + if(ptr == 0) { + MEMODSlx("HeapAlloc failed on size!!!", size); + return 0; + } + + HeapAdd(ptr, size); + return -1; +} + +int VMem::HeapAdd(void *p, size_t size) +{ /* if the block can be succesfully added to the heap, returns 0; otherwise -1. */ + int index; + + /* Check size, then round size down to next long word boundary. */ + if(size < minAllocSize) + return -1; + + size = (size_t)ROUND_DOWN(size); + PBLOCK ptr = (PBLOCK)p; + + /* + * Search for another heap area that's contiguous with the bottom of this new area. + * (It should be extremely unusual to find one that's contiguous with the top). + */ + for(index = 0; index < m_nHeaps; ++index) { + if(ptr == m_heaps[index].base + (int)m_heaps[index].len) { + /* + * The new block is contiguous with a previously allocated heap area. Add its + * length to that of the previous heap. Merge it with the the dummy end-of-heap + * area marker of the previous heap. + */ + m_heaps[index].len += size; + break; + } + } + + if(index == m_nHeaps) { + /* The new block is not contiguous. Add it to the heap list. */ + if(m_nHeaps == maxHeaps) { + return -1; /* too many non-contiguous heaps */ + } + m_heaps[m_nHeaps].base = ptr; + m_heaps[m_nHeaps].len = size; + m_nHeaps++; + + /* + * Reserve the first LONG in the block for the ending boundary tag of a dummy + * block at the start of the heap area. + */ + size -= minBlockSize; + ptr += minBlockSize; + PSIZE(ptr) = 1; /* mark the dummy previous block as allocated */ + } + + /* + * Convert the heap to one large block. Set up its boundary tags, and those of + * marker block after it. The marker block before the heap will already have + * been set up if this heap is not contiguous with the end of another heap. + */ + SetTags(ptr, size | 1); + PBLOCK next = ptr + size; /* point to dummy end block */ + SIZE(next) = 1; /* mark the dummy end block as allocated */ + + /* + * Link the block to the start of the free list by calling free(). + * This will merge the block with any adjacent free blocks. + */ + Free(ptr); + return 0; +} + + +void* VMem::Expand(void* block, size_t size) +{ + /* + * Adjust the size of the block to be a multiple of sizeof(long), and add the + * overhead for the boundary tags. Disallow negative or zero sizes. + */ + size_t realsize = (size < blockOverhead) ? minAllocSize : (size_t)ROUND_UP(size) + minBlockSize; + if((int)realsize < minAllocSize || size == 0) + return NULL; + + PBLOCK ptr = (PBLOCK)block; + + /* if the current size is the same as requested, do nothing. */ + size_t cursize = SIZE(ptr) & ~1; + if(cursize == realsize) { + return block; + } + + /* if the block is being shrunk, convert the remainder of the block into a new free block. */ + if(realsize <= cursize) { + size_t nextsize = cursize - realsize; /* size of new remainder block */ + if(nextsize >= minAllocSize) { + /* + * Split the block + * Set boundary tags for the resized block and the new block. + */ + SetTags(ptr, realsize | 1); + ptr += realsize; + + /* + * add the new block to the free list. + * call Free to merge this block with next block if free + */ + SetTags(ptr, nextsize | 1); + Free(ptr); + } + + return block; + } + + PBLOCK next = ptr + cursize; + size_t nextsize = SIZE(next); + + /* Check the next block for consistency.*/ + if((nextsize&1) == 0 && (nextsize + cursize) >= realsize) { + /* + * The next block is free and big enough. Add the part that's needed + * to our block, and split the remainder off into a new block. + */ + if(m_pRover == next) + m_pRover = NEXT(next); + + /* Unlink the next block from the free list. */ + Unlink(next); + cursize += nextsize; /* combine sizes */ + + size_t rem = cursize - realsize; /* size of remainder */ + if(rem >= minAllocSize) { + /* + * The remainder is big enough to be a new block. + * Set boundary tags for the resized block and the new block. + */ + next = ptr + realsize; + /* + * add the new block to the free list. + * next block cannot be free + */ + SetTags(next, rem); + AddToFreeList(next, m_pFreeList); + cursize = realsize; + } + /* Set the boundary tags to mark it as allocated. */ + SetTags(ptr, cursize | 1); + return ((void *)ptr); + } + return NULL; +} + +#ifdef _DEBUG_MEM +#define LOG_FILENAME "P:\\Apps\\Perl\\Result.txt" + +void MemoryUsageMessage(char *str, long x, long y, int c) +{ + static FILE* fp = NULL; + char szBuffer[512]; + if(str) { + if(!fp) + fp = fopen(LOG_FILENAME, "w"); + sprintf(szBuffer, str, x, y, c); + fputs(szBuffer, fp); + } + else { + fflush(fp); + fclose(fp); + } +} + +void VMem::WalkHeap(void) +{ + if(!m_pRover) { + MemoryUsageMessage("VMem heaps used %d\n", m_nHeaps, 0, 0); + } + + /* Walk all the heaps - verify structures */ + for(int index = 0; index < m_nHeaps; ++index) { + PBLOCK ptr = m_heaps[index].base; + size_t size = m_heaps[index].len; + ASSERT(HeapValidate(m_hHeap, HEAP_NO_SERIALIZE, p)); + + /* set over reserved header block */ + size -= minBlockSize; + ptr += minBlockSize; + PBLOCK pLast = ptr + size; + ASSERT(PSIZE(ptr) == 1); /* dummy previous block is allocated */ + ASSERT(SIZE(pLast) == 1); /* dummy next block is allocated */ + while(ptr < pLast) { + ASSERT(ptr > m_heaps[index].base); + size_t cursize = SIZE(ptr) & ~1; + ASSERT((PSIZE(ptr+cursize) & ~1) == cursize); + if(!m_pRover) { + MemoryUsageMessage("Memory Block %08x: Size %08x %c\n", (long)ptr, cursize, (SIZE(p)&1) ? 'x' : ' '); + } + if(!(SIZE(ptr)&1)) { + /* this block is on the free list */ + PBLOCK tmp = NEXT(ptr); + while(tmp != ptr) { + ASSERT((SIZE(tmp)&1)==0); + if(tmp == m_pFreeList) + break; + ASSERT(NEXT(tmp)); + tmp = NEXT(tmp); + } + if(tmp == ptr) { + MemoryUsageMessage("Memory Block %08x: Size %08x free but not in free list\n", (long)ptr, cursize, 0); + } + } + ptr += cursize; + } + } + if(!m_pRover) { + MemoryUsageMessage(NULL, 0, 0, 0); + } +} +#endif + +#endif /* ___VMEM_H_INC___ */ |