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/*
Miranda IM: the free IM client for Microsoft* Windows*
Copyright 2000-2003 Miranda ICQ/IM project,
all portions of this codebase are copyrighted to the people
listed in contributors.txt.
This program is free software; you can redistribute it and/or
modify it under the terms of the GNU General Public License
as published by the Free Software Foundation; either version 2
of the License, or (at your option) any later version.
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program; if not, write to the Free Software
Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*/
#include "commonheaders.h"
#include "database.h"
#define CACHESECTIONSIZE 4096
#define CACHESECTIONCOUNT 32
extern HANDLE hDbFile;
extern CRITICAL_SECTION csDbAccess;
static BOOL safetyMode=TRUE;
static PBYTE pDbCache;
static DWORD lastUseCounter;
struct DBCacheSectionInfo {
DWORD ofsBase;
DWORD lastUsed;
} static cacheSectionInfo[CACHESECTIONCOUNT];
static __inline int FindSectionForOffset(const DWORD ofs)
{
int i;
for(i=0;i<CACHESECTIONCOUNT;i++)
if(ofs>=cacheSectionInfo[i].ofsBase && ofs<cacheSectionInfo[i].ofsBase+CACHESECTIONSIZE)
return i;
return -1;
}
static __inline int FindLRUSection(void)
{
int i,lru=0;
DWORD lowestLastUse=cacheSectionInfo[0].lastUsed;
for(i=1;i<CACHESECTIONCOUNT;i++) if(cacheSectionInfo[i].lastUsed<lowestLastUse) {lru=i; lowestLastUse=cacheSectionInfo[i].lastUsed;}
return lru;
}
static __inline void LoadSection(const int i,DWORD ofs)
{
cacheSectionInfo[i].ofsBase=ofs-ofs%CACHESECTIONSIZE;
log1("readsect %08x",ofs);
SetFilePointer(hDbFile,cacheSectionInfo[i].ofsBase,NULL,FILE_BEGIN);
ReadFile(hDbFile,pDbCache+i*CACHESECTIONSIZE,CACHESECTIONSIZE,&ofs,NULL);
}
static __inline void MoveSection(int *sectId,int dest)
{
CopyMemory(pDbCache+dest*CACHESECTIONSIZE,pDbCache+(*sectId)*CACHESECTIONSIZE,CACHESECTIONSIZE);
cacheSectionInfo[dest].ofsBase=cacheSectionInfo[*sectId].ofsBase;
*sectId=dest;
}
//we are assumed to be in a mutex here
PBYTE DBRead(DWORD ofs,int bytesRequired,int *bytesAvail)
{
int part1sect;
int part2sect;
part1sect = FindSectionForOffset(ofs);
if (ofs%CACHESECTIONSIZE+bytesRequired<CACHESECTIONSIZE) {
//only one section required
if(part1sect==-1) {
part1sect=FindLRUSection();
LoadSection(part1sect,ofs);
}
cacheSectionInfo[part1sect].lastUsed=++lastUseCounter;
if(bytesAvail!=NULL) *bytesAvail=cacheSectionInfo[part1sect].ofsBase+CACHESECTIONSIZE-ofs;
return pDbCache+part1sect*CACHESECTIONSIZE+(ofs-cacheSectionInfo[part1sect].ofsBase);
}
//two sections are required
part2sect=FindSectionForOffset(ofs+CACHESECTIONSIZE);
if(part1sect!=-1) {
if(part2sect==-1) { //first part in cache, but not second part
if(part1sect==CACHESECTIONCOUNT-1) MoveSection(&part1sect,0);
LoadSection(part1sect+1,ofs+CACHESECTIONSIZE);
}
else if(part2sect!=part1sect+1) { //both parts are in cache, but not already consecutive
if(part1sect==CACHESECTIONCOUNT-1) {
//first part is at end, move to before second part
if(part2sect==0) //second part is at start: need to move both
MoveSection(&part2sect,1);
MoveSection(&part1sect,part2sect-1);
}
else //move second part to after first part
MoveSection(&part2sect,part1sect+1);
}
}
else {
if(part2sect==-1) { //neither section is in cache
part1sect=0; part2sect=1;
LoadSection(part1sect,ofs); LoadSection(part2sect,ofs+CACHESECTIONSIZE);
}
else { //part 2 is in cache, but not part 1
if(part2sect==0) MoveSection(&part2sect,1);
part1sect=part2sect-1;
LoadSection(part1sect,ofs);
}
}
//both sections are now consecutive, starting at part1sect
cacheSectionInfo[part1sect].lastUsed=++lastUseCounter;
cacheSectionInfo[part1sect+1].lastUsed=++lastUseCounter;
if(bytesAvail!=NULL) *bytesAvail=cacheSectionInfo[part1sect+1].ofsBase+CACHESECTIONSIZE-ofs;
return pDbCache+part1sect*CACHESECTIONSIZE+(ofs-cacheSectionInfo[part1sect].ofsBase);
}
//we are assumed to be in a mutex here
void DBWrite(DWORD ofs,PVOID pData,int bytes)
{
//write direct, and rely on Windows' write caching
DWORD bytesWritten;
int i;
log2("write %d@%08x",bytes,ofs);
SetFilePointer(hDbFile,ofs,NULL,FILE_BEGIN);
if (WriteFile(hDbFile,pData,bytes,&bytesWritten,NULL)==0)
{
DatabaseCorruption();
}
logg();
//check if any of the cache sections contain this bit
for(i=0;i<CACHESECTIONCOUNT;i++) {
if(ofs+bytes>=cacheSectionInfo[i].ofsBase && ofs<cacheSectionInfo[i].ofsBase+CACHESECTIONSIZE) {
if(ofs<cacheSectionInfo[i].ofsBase) { //don't start at beginning
if(ofs+bytes>=cacheSectionInfo[i].ofsBase+CACHESECTIONSIZE) //don't finish at end
CopyMemory(pDbCache+i*CACHESECTIONSIZE,(PBYTE)pData+cacheSectionInfo[i].ofsBase-ofs,CACHESECTIONSIZE);
else CopyMemory(pDbCache+i*CACHESECTIONSIZE,(PBYTE)pData+cacheSectionInfo[i].ofsBase-ofs,bytes-(cacheSectionInfo[i].ofsBase-ofs));
}
else { //start at beginning
if(ofs+bytes>=cacheSectionInfo[i].ofsBase+CACHESECTIONSIZE) //don't finish at end
CopyMemory(pDbCache+i*CACHESECTIONSIZE+ofs-cacheSectionInfo[i].ofsBase,pData,cacheSectionInfo[i].ofsBase+CACHESECTIONSIZE-ofs);
else CopyMemory(pDbCache+i*CACHESECTIONSIZE+ofs-cacheSectionInfo[i].ofsBase,pData,bytes);
}
}
}
}
void DBMoveChunk(DWORD ofsDest,DWORD ofsSource,int bytes)
{
DWORD bytesRead;
PBYTE buf;
log3("move %d %08x->%08x",bytes,ofsSource,ofsDest);
buf=(PBYTE)mir_alloc(bytes);
SetFilePointer(hDbFile,ofsSource,NULL,FILE_BEGIN);
ReadFile(hDbFile,buf,bytes,&bytesRead,NULL);
DBWrite(ofsDest,buf,bytes);
mir_free(buf);
logg();
}
static UINT_PTR flushBuffersTimerId;
static VOID CALLBACK DoBufferFlushTimerProc(HWND hwnd,UINT message,UINT_PTR idEvent,DWORD dwTime)
{
KillTimer(NULL,flushBuffersTimerId);
log0("tflush1");
FlushFileBuffers(hDbFile);
log0("tflush2");
}
void DBFlush(int setting)
{
if(!setting) {
log0("nflush1");
if(safetyMode) FlushFileBuffers(hDbFile);
log0("nflush2");
return;
}
KillTimer(NULL,flushBuffersTimerId);
flushBuffersTimerId=SetTimer(NULL,flushBuffersTimerId,50,DoBufferFlushTimerProc);
}
static INT_PTR CacheSetSafetyMode(WPARAM wParam,LPARAM lParam)
{
EnterCriticalSection(&csDbAccess);
safetyMode=wParam;
LeaveCriticalSection(&csDbAccess);
if(safetyMode) FlushFileBuffers(hDbFile);
return 0;
}
int InitCache(void)
{
int i;
DWORD bytesRead;
CreateServiceFunction(MS_DB_SETSAFETYMODE,CacheSetSafetyMode);
pDbCache=(PBYTE)mir_alloc(CACHESECTIONSIZE*CACHESECTIONCOUNT);
lastUseCounter=CACHESECTIONCOUNT;
for(i=0;i<CACHESECTIONCOUNT;i++) {
cacheSectionInfo[i].ofsBase=0;
cacheSectionInfo[i].lastUsed=i;
SetFilePointer(hDbFile,cacheSectionInfo[i].ofsBase,NULL,FILE_BEGIN);
ReadFile(hDbFile,pDbCache+i*CACHESECTIONSIZE,CACHESECTIONSIZE,&bytesRead,NULL);
}
return 0;
}
void UninitCache(void)
{
mir_free(pDbCache);
KillTimer(NULL,flushBuffersTimerId);
}
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