C语言实现运行与UNIX平台的内存数据库

#include "MemDataBase.h" #define HEAD_TABLE_NAME_LEN 64 #define HEAD_RESERVED_LEN 128 #define MDB_IPC_MODE 0660 #define MAX_KEY_NUM 10 typedef struct { int iKeyOffSet; /* TheKey fieldoffset */ int iKeyLen; /* The Keyfield len */ }TABLE_KEY_DEF; typedef struct { char sTableName[HEAD_TABLE_NAME_LEN]; /* The name of table*/ long lRecordNum; /* The total number of record in table */ int iRecordLen; /* The length of recode */ long lMaxRecordNum; /* The max number of record in table */ char sReserved[HEAD_RESERVED_LEN]; /* The reserved area*/ int iKeyNum; /* The Key field number */ TABLE_KEY_DEF stuTableKeyBuf[MAX_KEY_NUM]; /* The Table Key define */ }TABLE_HEAD_DEF; static TABLE_HEAD_DEF stuTableHeadBuf; int CreateMemDB(MEMDATABASE **pMemDB,char *pTableName,int iIpcKey,long lMaxRecord,int RecordLen) { int iRet; memset((char*)&stuTableHeadBuf,0,sizeof(TABLE_HEAD_DEF)); if(strlen(pTableName)>HEAD_TABLE_NAME_LEN) return T_MDB_ENAMELEN; memcpy(stuTableHeadBuf.sTableName,pTableName,strlen(pTableName)); stuTableHeadBuf.iRecordLen = RecordLen; stuTableHeadBuf.lMaxRecordNum = lMaxRecord; stuTableHeadBuf.lRecordNum = 0; stuTableHeadBuf.iKeyNum = 0; *pMemDB = (MEMDATABASE*)malloc(sizeof(MEMDATABASE)); if(*pMemDB==NULL) return T_MDB_ENOMEM; (*pMemDB)->iFetchKeyNum = 0; (*pMemDB)->lFetchNum = 1; (*pMemDB)->iIpcKey = iIpcKey; (*pMemDB)->iShmId = shmget(iIpcKey, stuTableHeadBuf.iRecordLen*stuTableHeadBuf.lMaxRecordNum + sizeof(stuTableHeadBuf), IPC_CREAT|MDB_IPC_MODE); if( (*pMemDB)->iShmId<0 ) { return T_MDB_ESHMGET; } (*pMemDB)->pShmArea = (char*)shmat((*pMemDB)->iShmId,NULL,0); if( (long)(*pMemDB)->pShmArea==-1 ) { return T_MDB_ESHMAT; } memcpy((*pMemDB)->pShmArea,(char*)&stuTableHeadBuf,sizeof(stuTableHeadBuf)); (*pMemDB)->iSemId = semget(iIpcKey,1,IPC_CREAT|MDB_IPC_MODE); if( (*pMemDB)->iSemId<0 ) { return T_MDB_ESEMGET; } iRet = semctl((*pMemDB)->iSemId,0,SETVAL,1); if( iRet<0 ) { return T_MDB_ESEMCTL; } return T_SUCCESS; } void GetHead(char *pShmArea) { memcpy((char*)&stuTableHeadBuf,(char*)pShmArea,sizeof(TABLE_HEAD_DEF)); } void PutHead(char *pShmArea) { memcpy((char*)pShmArea,(char*)&stuTableHeadBuf,sizeof(TABLE_HEAD_DEF)); } int SetTableKey(MEMDATABASE *pMemDB,int iKeyOffSet,int iKeyLen) { int i; GetHead(pMemDB->pShmArea); for(i=0;i<stuTableHeadBuf.iKeyNum;i++) { if((stuTableHeadBuf.stuTableKeyBuf[i].iKeyOffSet == iKeyOffSet)&& (stuTableHeadBuf.stuTableKeyBuf[i].iKeyLen == iKeyLen)) { return T_SUCCESS; } } if(stuTableHeadBuf.iKeyNum >= MAX_KEY_NUM) return T_MDB_EMAXKEY; stuTableHeadBuf.stuTableKeyBuf[stuTableHeadBuf.iKeyNum].iKeyOffSet = iKeyOffSet; stuTableHeadBuf.stuTableKeyBuf[stuTableHeadBuf.iKeyNum].iKeyLen = iKeyLen; stuTableHeadBuf.iKeyNum++; PutHead(pMemDB->pShmArea); return T_SUCCESS; } int CompareKey(MEMDATABASE *pMemDB,char *pShmBuf,char *pInBuf) { int i,iRet; GetHead(pMemDB->pShmArea); for(i=0;i<stuTableHeadBuf.iKeyNum;i++) { iRet = memcmp((char*)&pInBuf[stuTableHeadBuf.stuTableKeyBuf[i].iKeyOffSet], (char*)&pShmBuf[stuTableHeadBuf.stuTableKeyBuf[i].iKeyOffSet], stuTableHeadBuf.stuTableKeyBuf[i].iKeyLen); if(iRet!=0) return iRet; } return 0; } int ShmLock(int iSemId) { int iRet; struct sembuf stuSemBuf; stuSemBuf.sem_num = 0; stuSemBuf.sem_op = -1; stuSemBuf.sem_flg = 0; iRet = semop(iSemId,&stuSemBuf,1); return iRet; } int ShmUnLock(int iSemId) { int iRet; struct sembuf stuSemBuf; stuSemBuf.sem_num = 0; stuSemBuf.sem_op = 1; stuSemBuf.sem_flg = 0; iRet = semop(iSemId,&stuSemBuf,1); return iRet; } char * LocateShm(char *pShmArea,int iNum) { if( iNum>stuTableHeadBuf.lMaxRecordNum ) { return NULL; } return pShmArea + (iNum-1)*stuTableHeadBuf.iRecordLen + sizeof(stuTableHeadBuf); } int SearchRecord(MEMDATABASE *pMemDB,char *pInBuf,int *iPosition) { int iRet,i,iMax,iMin; char *pRecordBuf; iMin = i = 0; iMax = stuTableHeadBuf.lRecordNum-1; while(iMin<=iMax) { i = (iMax+iMin)/2; pRecordBuf = LocateShm(pMemDB->pShmArea,i+1); iRet = CompareKey(pMemDB,pRecordBuf,pInBuf); switch(iRet) { case 0: *iPosition = i+1; return T_SUCCESS; break; case 1: iMin = i+1; break; case -1: iMax = i-1; break; } } if(iMin>iMax&&i==iMax) i=iMin; *iPosition = i+1; return T_MDB_NOTFOUND; } int DropMemDB(MEMDATABASE *pMemDB) { int iRet; iRet = shmctl(pMemDB->iShmId,IPC_RMID,0); if( iRet<0 ) { return T_MDB_ESHMRM; } iRet = semctl(pMemDB->iSemId,IPC_RMID,0); if( iRet<0 ) { return T_MDB_ESEMRM; } free(pMemDB); return T_SUCCESS; } int AttachMemDB(MEMDATABASE **pMemDB,int iIpcKey) { *pMemDB = (MEMDATABASE*)malloc(sizeof(MEMDATABASE)); if(*pMemDB==NULL) return T_MDB_ENOMEM; (*pMemDB)->iFetchKeyNum = 0; (*pMemDB)->lFetchNum = 1; (*pMemDB)->iIpcKey = iIpcKey; (*pMemDB)->iShmId = shmget(iIpcKey,0,MDB_IPC_MODE); if( (*pMemDB)->iShmId<0 ) { return T_MDB_ESHMGET; } (*pMemDB)->pShmArea = (char*)shmat((*pMemDB)->iShmId,NULL,0); if( (long)(*pMemDB)->pShmArea==-1 ) { return T_MDB_ESHMAT; } (*pMemDB)->iSemId = semget(iIpcKey,1,MDB_IPC_MODE); if( (*pMemDB)->iSemId<0 ) { return T_MDB_ESEMGET; } return T_SUCCESS; } int DeclareTableKey(MEMDATABASE *pMemDB,int iKeyOffSet,int iKeyLen,void *pValue) { int i; pMemDB->lFetchNum = 1; for(i=0;i<pMemDB->iFetchKeyNum;i++) { if((pMemDB->stuFetchKeyBuf[i].iKeyOffSet==iKeyOffSet)&& (pMemDB->stuFetchKeyBuf[i].iKeyLen==iKeyLen)) { memcpy(pMemDB->stuFetchKeyBuf[i].sValue,(char*)pValue,iKeyLen); return T_SUCCESS; } } if(pMemDB->iFetchKeyNum>=MAX_FETCHKEY_NUM) return T_MDB_EMAXFETCHKEY; pMemDB->stuFetchKeyBuf[pMemDB->iFetchKeyNum].iKeyOffSet = iKeyOffSet; pMemDB->stuFetchKeyBuf[pMemDB->iFetchKeyNum].iKeyLen = iKeyLen; memcpy(pMemDB->stuFetchKeyBuf[pMemDB->iFetchKeyNum].sValue,(char*)pValue,iKeyLen); pMemDB->iFetchKeyNum++; return T_SUCCESS; } int CloseCursorMemDB(MEMDATABASE *pMemDB) { pMemDB->lFetchNum = 1; pMemDB->iFetchKeyNum = 0; return T_SUCCESS; } int FetchCursorMemDB(MEMDATABASE *pMemDB,char *pInBuffer) { int iRet; char *pRecordBuf; GetHead(pMemDB->pShmArea); while(stuTableHeadBuf.lRecordNum >=pMemDB->lFetchNum ) { pRecordBuf = LocateShm(pMemDB->pShmArea,pMemDB->lFetchNum++); iRet = FetchCondition(pMemDB,pRecordBuf); if(iRet!=T_SUCCESS) continue; memcpy((char*)pInBuffer,pRecordBuf,stuTableHeadBuf.iRecordLen); return T_SUCCESS; } return T_MDB_NOTFOUND; } int FetchCondition(MEMDATABASE *pMemDB,char *pRecordBuf) { int i; for(i=0;i<pMemDB->iFetchKeyNum;i++) { if(memcmp((char*)&pRecordBuf[pMemDB->stuFetchKeyBuf[i].iKeyOffSet], (char*)pMemDB->stuFetchKeyBuf[i].sValue, pMemDB->stuFetchKeyBuf[i].iKeyLen)!=0) return T_MDB_NOTMATCH; } return T_SUCCESS; } int SelectOneMemDB(MEMDATABASE *pMemDB,char *pInBuffer) { char *pRecordBuf; GetHead(pMemDB->pShmArea); if(stuTableHeadBuf.lRecordNum > 0) { pRecordBuf = LocateShm(pMemDB->pShmArea,1); memcpy((char*)pInBuffer,pRecordBuf,stuTableHeadBuf.iRecordLen);