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Sweden-Number/ole/stg_bigblockfile.c

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/******************************************************************************
*
* BigBlockFile
*
* This is the implementation of a file that consists of blocks of
* a predetermined size.
* This class is used in the Compound File implementation of the
* IStorage and IStream interfaces. It provides the functionality
* to read and write any blocks in the file as well as setting and
* obtaining the size of the file.
* The blocks are indexed sequentially from the start of the file
* starting with -1.
*
* TODO:
* - Support for a transacted mode
*
* Copyright 1999 Thuy Nguyen
*
*/
#include <assert.h>
#include <stdlib.h>
#include <stdio.h>
#include <string.h>
#include "windows.h"
#include "winerror.h"
#include "ole.h"
#include "ole2.h"
#include "compobj.h"
#include "interfaces.h"
#include "storage32.h"
/***********************************************************
* Data structures used internally by the BigBlockFile
* class.
*/
/***
* Itdentifies a single big block and the related
* information
*/
struct BigBlock
{
BigBlock * next;
DWORD index;
DWORD access_mode;
LPVOID lpBlock;
};
/***
* This structure identifies the paged that are mapped
* from the file and their position in memory. It is
* also used to hold a reference count to those pages.
*/
struct MappedPage
{
MappedPage * next;
DWORD number;
int ref;
LPVOID lpBytes;
};
#define BLOCKS_PER_PAGE 128
#define PAGE_SIZE 65536
/***********************************************************
* Prototypes for private methods
*/
static void* BIGBLOCKFILE_GetMappedView(LPBIGBLOCKFILE This,
DWORD pagenum,
DWORD desired_access);
static void BIGBLOCKFILE_ReleaseMappedPage(LPBIGBLOCKFILE This,
DWORD pagenum,
DWORD access);
static void BIGBLOCKFILE_FreeAllMappedPages(LPBIGBLOCKFILE This);
static void* BIGBLOCKFILE_GetBigBlockPointer(LPBIGBLOCKFILE This,
ULONG index,
DWORD desired_access);
static BigBlock* BIGBLOCKFILE_GetBigBlockFromPointer(LPBIGBLOCKFILE This,
void* pBlock);
static void BIGBLOCKFILE_RemoveBlock(LPBIGBLOCKFILE This,
ULONG index);
static BigBlock* BIGBLOCKFILE_AddBigBlock(LPBIGBLOCKFILE This,
ULONG index);
static BigBlock* BIGBLOCKFILE_CreateBlock(ULONG index);
/******************************************************************************
* BIGBLOCKFILE_Construct
*
* Construct a big block file. Create the file mapping object.
* Create the read only mapped pages list, the writeable mapped page list
* and the blocks in use list.
*/
BigBlockFile * BIGBLOCKFILE_Construct(
HANDLE32 hFile,
ULONG blocksize)
{
LPBIGBLOCKFILE This;
This = (LPBIGBLOCKFILE)HeapAlloc(GetProcessHeap(), 0, sizeof(BigBlockFile));
if (This == NULL)
return NULL;
This->hfile = hFile;
if (This->hfile == INVALID_HANDLE_VALUE32)
{
HeapFree(GetProcessHeap(), 0, This);
return NULL;
}
/* create the file mapping object
*/
This->hfilemap = CreateFileMapping32A(This->hfile,
NULL,
PAGE_READWRITE,
0, 0,
NULL);
if (This->hfilemap == NULL)
{
CloseHandle(This->hfile);
HeapFree(GetProcessHeap(), 0, This);
return NULL;
}
/* initialize this
*/
This->filesize.LowPart = GetFileSize(This->hfile, NULL);
This->blocksize = blocksize;
/* create the read only mapped pages list
*/
This->headmap_ro = HeapAlloc(GetProcessHeap(), 0, sizeof(MappedPage));
if (This->headmap_ro == NULL)
{
CloseHandle(This->hfilemap);
CloseHandle(This->hfile);
HeapFree(GetProcessHeap(), 0, This);
return NULL;
}
This->headmap_ro->next = NULL;
/* create the writeable mapped pages list
*/
This->headmap_w = HeapAlloc(GetProcessHeap(), 0, sizeof(MappedPage));
if (This->headmap_w == NULL)
{
CloseHandle(This->hfilemap);
CloseHandle(This->hfile);
HeapFree(GetProcessHeap(), 0, This->headmap_ro);
HeapFree(GetProcessHeap(), 0, This);
return NULL;
}
This->headmap_w->next = NULL;
/* initialize the block list
*/
This->headblock = NULL;
return This;
}
/******************************************************************************
* BIGBLOCKFILE_Destructor
*
* Destructor. Clean up, free memory.
*/
void BIGBLOCKFILE_Destructor(
LPBIGBLOCKFILE This)
{
/* unmap all views and destroy the mapped page lists
*/
BIGBLOCKFILE_FreeAllMappedPages(This);
HeapFree(GetProcessHeap(), 0, This->headmap_ro);
HeapFree(GetProcessHeap(), 0, This->headmap_w);
/* close all open handles
*/
CloseHandle(This->hfilemap);
CloseHandle(This->hfile);
/* destroy this
*/
HeapFree(GetProcessHeap(), 0, This);
}
/******************************************************************************
* BIGBLOCKFILE_GetROBigBlock
*
* Returns the specified block in read only mode.
* Will return NULL if the block doesn't exists.
*/
void* BIGBLOCKFILE_GetROBigBlock(
LPBIGBLOCKFILE This,
ULONG index)
{
/*
* block index starts at -1
* translate to zero based index
*/
if (index == 0xffffffff)
index = 0;
else
index++;
/*
* validate the block index
*
*/
if ((This->blocksize * (index + 1)) >
(This->filesize.LowPart +
(This->blocksize - (This->filesize.LowPart % This->blocksize))))
return 0;
return BIGBLOCKFILE_GetBigBlockPointer(This, index, FILE_MAP_READ);
}
/******************************************************************************
* BIGBLOCKFILE_GetBigBlock
*
* Returns the specified block.
* Will grow the file if necessary.
*/
void* BIGBLOCKFILE_GetBigBlock(LPBIGBLOCKFILE This, ULONG index)
{
/*
* block index starts at -1
* translate to zero based index
*/
if (index == 0xffffffff)
index = 0;
else
index++;
/*
* make sure that the block physically exists
*/
if ((This->blocksize * (index + 1)) > This->filesize.LowPart)
{
ULARGE_INTEGER newSize;
newSize.HighPart = 0;
newSize.LowPart = This->blocksize * (index + 1);
BIGBLOCKFILE_SetSize(This, newSize);
}
return BIGBLOCKFILE_GetBigBlockPointer(This, index, FILE_MAP_WRITE);
}
/******************************************************************************
* BIGBLOCKFILE_ReleaseBigBlock
*
* Releases the specified block.
*
*/
void BIGBLOCKFILE_ReleaseBigBlock(LPBIGBLOCKFILE This, void *pBlock)
{
DWORD page_num;
BigBlock* theBigBlock;
if (pBlock == NULL)
return;
/*
* get the block from the block list
*/
theBigBlock = BIGBLOCKFILE_GetBigBlockFromPointer(This, pBlock);
if (theBigBlock == NULL)
return;
/*
* find out which page this block is in
*/
page_num = theBigBlock->index / BLOCKS_PER_PAGE;
/*
* release this page
*/
BIGBLOCKFILE_ReleaseMappedPage(This, page_num, theBigBlock->access_mode);
/*
* remove block from list
*/
BIGBLOCKFILE_RemoveBlock(This, theBigBlock->index);
}
/******************************************************************************
* BIGBLOCKFILE_SetSize
*
* Sets the size of the file.
*
*/
void BIGBLOCKFILE_SetSize(LPBIGBLOCKFILE This, ULARGE_INTEGER newSize)
{
if (This->filesize.LowPart == newSize.LowPart)
return;
/*
* unmap all views, must be done before call to SetEndFile
*/
BIGBLOCKFILE_FreeAllMappedPages(This);
/*
* close file-mapping object, must be done before call to SetEndFile
*/
CloseHandle(This->hfilemap);
This->hfilemap = NULL;
/*
* set the new end of file
*/
SetFilePointer(This->hfile, newSize.LowPart, NULL, FILE_BEGIN);
SetEndOfFile(This->hfile);
/*
* re-create the file mapping object
*/
This->hfilemap = CreateFileMapping32A(This->hfile,
NULL,
PAGE_READWRITE,
0, 0,
NULL);
This->filesize.LowPart = newSize.LowPart;
This->filesize.HighPart = newSize.HighPart;
}
/******************************************************************************
* BIGBLOCKFILE_GetSize
*
* Returns the size of the file.
*
*/
ULARGE_INTEGER BIGBLOCKFILE_GetSize(LPBIGBLOCKFILE This)
{
return This->filesize;
}
/******************************************************************************
* BIGBLOCKFILE_GetBigBlockPointer [PRIVATE]
*
* Returns a pointer to the specified block.
*/
static void* BIGBLOCKFILE_GetBigBlockPointer(
LPBIGBLOCKFILE This,
ULONG index,
DWORD desired_access)
{
DWORD page_num, block_num;
void * pBytes;
BigBlock *aBigBlock;
/* get the big block from the list or add it to the list
*/
aBigBlock = BIGBLOCKFILE_AddBigBlock(This, index);
if (aBigBlock == NULL)
return NULL;
/* we already have an address for this block
*/
if (aBigBlock->lpBlock != NULL)
{
/* make sure the desired access matches what we already have
*/
if (aBigBlock->access_mode == desired_access)
return aBigBlock->lpBlock;
else
return NULL;
}
/*
* else aBigBlock->lpBigBlock == NULL, it's a new block
*/
/* find out which page this block is in
*/
page_num = index / BLOCKS_PER_PAGE;
/* offset of the block in the page
*/
block_num = index % BLOCKS_PER_PAGE;
/* get a pointer to the first byte in the page
*/
pBytes = BIGBLOCKFILE_GetMappedView(This, page_num, desired_access);
if (pBytes == NULL)
return NULL;
/* initialize block
*/
aBigBlock->lpBlock = ((BYTE*)pBytes + (block_num*This->blocksize));
aBigBlock->access_mode = desired_access;
return aBigBlock->lpBlock;
}
/******************************************************************************
* BIGBLOCKFILE_CreateBlock [PRIVATE]
*
* Creates a node of the blocks list.
*/
static BigBlock* BIGBLOCKFILE_CreateBlock(
ULONG index)
{
BigBlock *newBigBlock;
/* create new list node
*/
newBigBlock = HeapAlloc(GetProcessHeap(), 0, sizeof(BigBlock));
if (newBigBlock == NULL)
return NULL;
/* initialize node
*/
newBigBlock->index = index;
newBigBlock->lpBlock = NULL;
return newBigBlock;
}
/******************************************************************************
* BIGBLOCKFILE_AddBigBlock [PRIVATE]
*
* Returns the specified block from the blocks list.
* If the block is not found in the list, we will create it and add it to the
* list.
*/
static BigBlock* BIGBLOCKFILE_AddBigBlock(
LPBIGBLOCKFILE This,
ULONG index)
{
BigBlock *current = This->headblock;
BigBlock *newBigBlock;
if (current == NULL) /* empty list */
{
newBigBlock = BIGBLOCKFILE_CreateBlock(index);
if (newBigBlock != NULL)
{
newBigBlock->next = NULL;
This->headblock = newBigBlock;
}
return newBigBlock;
}
else
{
/*
* special handling for head of the list
*/
if (current->index == index) /* it's already here */
return current;
else if (current->index > index) /* insertion at head of the list */
{
newBigBlock = BIGBLOCKFILE_CreateBlock(index);
if (newBigBlock != NULL)
{
newBigBlock->next = current;
This->headblock = newBigBlock;
}
return newBigBlock;
}
}
/* iterate through rest the list
*/
while (current->next != NULL)
{
if (current->next->index == index) /* found it */
{
return current->next;
}
else if (current->next->index > index) /* it's not in the list */
{
newBigBlock = BIGBLOCKFILE_CreateBlock(index);
if (newBigBlock != NULL)
{
newBigBlock->next = current->next;
current->next = newBigBlock;
}
return newBigBlock;
}
else
current = current->next;
}
/*
* insertion at end of the list
*/
if (current->next == NULL)
{
newBigBlock = BIGBLOCKFILE_CreateBlock(index);
if (newBigBlock != NULL)
{
newBigBlock->next = NULL;
current->next = newBigBlock;
}
return newBigBlock;
}
return NULL;
}
/******************************************************************************
* BIGBLOCKFILE_RemoveBlock [PRIVATE]
*
* Removes the specified block from the blocks list.
*/
static void BIGBLOCKFILE_RemoveBlock(
LPBIGBLOCKFILE This,
ULONG index)
{
BigBlock *current = This->headblock;
/*
* empty list
*/
if (current == NULL)
return;
/*
*special case: removing head of list
*/
if (current->index == index)
{
/*
* set new head free the old one
*/
This->headblock = current->next;
HeapFree(GetProcessHeap(), 0, current);
return;
}
/*
* iterate through rest of the list
*/
while (current->next != NULL)
{
if (current->next->index == index) /* found it */
{
/*
* unlink the block and free the block
*/
current->next = current->next->next;
HeapFree(GetProcessHeap(), 0, current->next);
return;
}
else
{
/* next node
*/
current = current->next;
}
}
}
/******************************************************************************
* BIGBLOCKFILE_GetBigBlockFromPointer [PRIVATE]
*
* Given a block pointer, this will return the corresponding block
* from the blocks list.
*/
static BigBlock* BIGBLOCKFILE_GetBigBlockFromPointer(
LPBIGBLOCKFILE This,
void* pBlock)
{
BigBlock *current = This->headblock;
while (current != NULL)
{
if (current->lpBlock == pBlock)
{
break;
}
else
current = current->next;
}
return current;
}
/******************************************************************************
* BIGBLOCKFILE_GetMappedView [PRIVATE]
*
* Gets the page requested if it is already mapped.
* If it's not already mapped, this method will map it
*/
static void * BIGBLOCKFILE_GetMappedView(
LPBIGBLOCKFILE This,
DWORD pagenum,
DWORD desired_access)
{
MappedPage * current;
MappedPage * newMappedPage;
DWORD hioffset, lowoffset;
/* use correct list
*/
if (desired_access == FILE_MAP_READ)
current = This->headmap_ro;
else if (desired_access == FILE_MAP_WRITE)
current = This->headmap_w;
else
return NULL;
hioffset = 0;
lowoffset = PAGE_SIZE * pagenum;
while (current->next != NULL)
{
if (current->next->number == pagenum) /* page already mapped */
{
current->next->ref++;
return current->next->lpBytes;
}
else if (current->next->number > pagenum) /* this page is not mapped yet */
{
/* allocate new MappedPage
*/
newMappedPage = HeapAlloc(GetProcessHeap(), 0, sizeof(MappedPage));
if (newMappedPage == NULL)
return NULL;
/* initialize the new MappedPage
*/
newMappedPage->number = pagenum;
newMappedPage->ref = 1;
newMappedPage->next = current->next;
current->next = newMappedPage;
/* actually map the page
*/
if (This->filesize.LowPart < PAGE_SIZE)
{
newMappedPage->lpBytes = MapViewOfFile(This->hfilemap,
desired_access,
hioffset, lowoffset,
This->filesize.LowPart);
}
else
{
newMappedPage->lpBytes = MapViewOfFile(This->hfilemap,
desired_access,
hioffset,
lowoffset,
PAGE_SIZE);
}
return newMappedPage->lpBytes;
}
else
current = current->next;
}
/* reached end of the list, this view is not mapped yet
*/
if (current->next == NULL)
{
/* allocate new MappedPage
*/
newMappedPage = HeapAlloc(GetProcessHeap(), 0, sizeof(MappedPage));
if (newMappedPage == NULL)
return NULL;
/* initialize the new MappedPage
*/
newMappedPage->number = pagenum;
newMappedPage->ref = 1;
newMappedPage->next = NULL;
current->next = newMappedPage;
/* actually map the page
*/
if (This->filesize.LowPart < PAGE_SIZE)
{
newMappedPage->lpBytes = MapViewOfFile(This->hfilemap,
desired_access,
hioffset,
lowoffset,
This->filesize.LowPart);
}
else
{
newMappedPage->lpBytes = MapViewOfFile(This->hfilemap,
desired_access,
hioffset,
lowoffset,
PAGE_SIZE);
}
return newMappedPage->lpBytes;
}
return NULL;
}
/******************************************************************************
* BIGBLOCKFILE_ReleaseMappedPage [PRIVATE]
*
* Decrements the reference count of the mapped page.
* If the page is not used anymore it will be unmapped.
*/
static void BIGBLOCKFILE_ReleaseMappedPage(
LPBIGBLOCKFILE This,
DWORD pagenum,
DWORD access)
{
MappedPage * previous;
MappedPage * current;
/* use the list corresponding to the desired access mode
*/
if (access == FILE_MAP_READ)
previous = This->headmap_ro;
else if (access == FILE_MAP_WRITE)
previous = This->headmap_w;
else
return;
current = previous->next;
/* search for the page in the list
*/
while (current != NULL)
{
if (current->number == pagenum)
{
/* decrement the reference count
*/
current->ref--;
if (current->ref == 0)
{
/* this page is not used anymore, we can unmap it
*/
UnmapViewOfFile(current->lpBytes);
previous->next = current->next;
HeapFree(GetProcessHeap(), 0, current);
}
return;
}
else
{
previous = current;
current = current->next;
}
}
}
/******************************************************************************
* BIGBLOCKFILE_FreeAllMappedPages [PRIVATE]
*
* Unmap all currently mapped pages.
* Empty both mapped pages lists.
*/
static void BIGBLOCKFILE_FreeAllMappedPages(
LPBIGBLOCKFILE This)
{
/*
* start with the read only list
*/
MappedPage * current = This->headmap_ro->next;
while (current != NULL)
{
/* unmap views
*/
UnmapViewOfFile(current->lpBytes);
/* free the nodes
*/
This->headmap_ro->next = current->next;
HeapFree(GetProcessHeap(), 0, current);
current = This->headmap_ro->next;
}
/*
* then do the write list
*/
current = This->headmap_w->next;
while (current != NULL)
{
/* unmap views
*/
UnmapViewOfFile(current->lpBytes);
/* free the nodes
*/
This->headmap_w->next = current->next;
HeapFree(GetProcessHeap(), 0, current);
current = This->headmap_w->next;
}
}
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