int RMM_InsertRec(int fileDesc, char *record, int recordSize)
{
int blockNum, ret, max_records, recordNum;
char *blockBuf, *HF_HeadBuf;
if ((HF_HeadBuf = malloc(BF_BLOCK_SIZE)) == NULL ) {
BF_Errno = BFE_NOMEM;
return (HF_errno = HFE_BFERROR);
}
if ((blockBuf = malloc(BF_BLOCK_SIZE)) == NULL ) {
BF_Errno = BFE_NOMEM;
return (HF_errno = HFE_BFERROR);
}
if(BF_GetThisBlock(fileDesc, 0, &HF_HeadBuf) != BFE_OK) //-> Fernei to HF_HEADER stin mnimi.
return (HF_errno = HFE_BFERROR); //
if ((blockNum = getFirstZeroBitPos(HF_HeadBuf,BF_BLOCK_SIZE)) == -1) //-> Psaxnei to HF_HEADER gia to 1o mi mideniko. Ean ola
return (HF_errno = HFE_EOF); // einai 1 epistrefei 'EOF'. I epistrefomeni timi '0'
blockNum ++; // anaferetai sto 1o block.
if ((ret = BF_GetThisBlock(fileDesc, blockNum, &blockBuf)) == BFE_INVALIDBLOCK) { //-> Epixeirei na ferei sti mnimi to block sto
if (BF_AllocBlock(fileDesc, &blockNum, &blockBuf) != BFE_OK) // opoio tha eisagagei tin eggrafi. Ean itan
return (HF_errno = HFE_BFERROR); // mi eguro block, to dimiourgei kanontas alloc.
} //
else if (ret != BFE_OK )
return (HF_errno = HFE_BFERROR);
max_records = BF_BLOCK_SIZE*8 / (recordSize*8 + 1); //-> Ypologizei to megisto plithos eggrafwn pou xwraei
// to kathe block.
for(recordNum=0 ; recordNum < max_records ; recordNum++) //-> Psaxnei sto anestrammeno bitmap tou block gia na
if (!isBitActive(blockBuf, BF_BLOCK_SIZE*8-1 -recordNum)) // vrei tin prwti adeia thesi eggrafis sto block,
break; // i opoia kai einai i 'recordNum'. Sigoura tha vrei
// mia adeia thesi eggrafis, mias kai to block epilexthike
// ef'oson den itan plirws gemato apo eggrafes.
//
memcpy(blockBuf + recordSize*recordNum, record, recordSize); //-> Adigrafei tin eggrafi sto block, stin thesi
// 'recordNum'.
setBit(blockBuf, BF_BLOCK_SIZE*8-1 -recordNum); //-> Enimerwnei to bitmap tou block gia to gemisma tis
// eggrafis.
if ((ret = FullOrEmpty(blockBuf, max_records, BF_BLOCK_SIZE, 1))) //-> Ean to block gemise me eggrafes, tote enimerwnei
setBit(HF_HeadBuf, blockNum-1); // to HF_HEADER gia to pleon plirws gemato block.
// Ean to to block einai gemato i 'ret' exei timi '1'
// alliws '0'.
if (BF_UnpinBlock(fileDesc, blockNum, 1) != BFE_OK) //-> Kanei unpin to block pou eisigage tin eggrafi me
return (HF_errno = HFE_BFERROR); // dirty=1.
if (BF_UnpinBlock(fileDesc, 0, ret) != BFE_OK) //-> Kanei unpin to HF_HEADER me dirty iso me tin timi
return (HF_errno = HFE_BFERROR); // tis 'ret' pou epistrafike parapanw.
return ((blockNum-1)*max_records + recordNum);
}
int RMM_DeleteRec(int fileDesc, int recId, int recordSize)
{
int full, max_records, blockNum, recordNum;
char *HF_HeadBuf, *blockBuf;
if (( HF_HeadBuf = malloc(BF_BLOCK_SIZE)) == NULL ) {
BF_Errno = BFE_NOMEM;
return (HF_errno = HFE_BFERROR);
}
if (( blockBuf = malloc ( BF_BLOCK_SIZE )) == NULL ) {
BF_Errno = BFE_NOMEM;
return (HF_errno = HFE_BFERROR);
}
if(BF_GetThisBlock(fileDesc, 0, &HF_HeadBuf) != BFE_OK) //-> Fernei to HF_HEADER sti mnimi.
return (HF_errno = HFE_BFERROR); //
max_records = BF_BLOCK_SIZE*8 / (recordSize*8 + 1); //-> Ypologizei to megisto plithos eggrafwn pou
// xwraei to kathe block.
blockNum = recId/max_records + 1; //-> Vriskei poio einai to block sto opoio vrisketai
// i eggrafi pou zitithike na diagrapsei.
if(BF_GetThisBlock(fileDesc, blockNum, &blockBuf) != BFE_OK) //-> Fernei stin mnimi to block sto opoio vrisketai
return (HF_errno = HFE_BFERROR); // i eggrafi pou zitithike na diagrapsei.
recordNum = recId % max_records; //-> Vriskei ti thesi tis eggrafis mesa sto block.
if(!isBitActive(blockBuf, BF_BLOCK_SIZE*8-1 -recordNum)) //-> Elegxei ean i eggrafi pou zitithike na diagrafei
{ if (BF_UnpinBlock(fileDesc, blockNum, 0) != BFE_OK) // ontws uparxei mesa sto block.
return (HF_errno = HFE_BFERROR);
return (HF_errno = HFE_INVALIDREC);
}
resetBit(blockBuf, BF_BLOCK_SIZE*8-1 -recordNum); //-> "Diagrafei" ti zitoumeni eggrafi sto block,
// midenizontas tin thesi tis sto bitmap tou block.
if(( full = isBitActive(HF_HeadBuf, blockNum-1 ))) //-> Elegxei to HF_HEADER gia na dei ean to block prin
resetBit(HF_HeadBuf, blockNum-1); // tin diagrafi tis eggrafis, itan plirws gemato.
// Ean nai, enimerwnei to HF_HEADER gia tin nea
// katastasi tou block.
if(BF_UnpinBlock(fileDesc, blockNum, 1) != BFE_OK) //-> Kanei unpin to block.
return (HF_errno = HFE_BFERROR); //
if(FullOrEmpty(blockBuf, max_records, BF_BLOCK_SIZE, 0)) //-> Elegxei, ean meta apo tin diagrafi tis eggrafis
if(BF_DisposeBlock(fileDesc, blockNum) != BFE_OK) // pou molis egine, to block den periexei kammia
return (HF_errno = HFE_BFERROR); // eggrafi. Ean nai, kanei dispose to adeio block.
if(BF_UnpinBlock(fileDesc, 0, full) != BFE_OK) //-> Kanei unpin to HF_HEADER me dirty iso me 'full',
return (HF_errno = HFE_BFERROR); // i opoia exei timi '0' i '1' analoga me to ean
// to block itan prin diagrafei oxi plirws gemato
// i plirws gemato, antistoixa.
return HFE_OK;
}
int RMM_GetThisRec(int fileDesc, int recId, char *record, int recordSize)
{
int max_records, blockNum, recordNum;
char *blockBuf;
if (( blockBuf = malloc(BF_BLOCK_SIZE)) == NULL) {
BF_Errno = BFE_NOMEM;
return (HF_errno = HFE_BFERROR);
}
max_records = (BF_BLOCK_SIZE*8) / (recordSize*8 + 1); //-> Ypologizei to megisto plithos eggrafwn
// pou xwraei to kathe block.
blockNum = recId / max_records + 1; //-> Vriskei poio einai to block sto opio vrisketai
// i eggrafi pou zitithike na diavasei.
recordNum = recId % max_records; //-> Vriskei ti thesi tis eggrafis mesa sto block.
if (BF_GetThisBlock(fileDesc, blockNum, &blockBuf) != BFE_OK ) //-> Fernei sti mnimi to block sto opoio
return (HF_errno = HFE_BFERROR); // vrisketai i eggrafi pou zitithike.
if (!isBitActive(blockBuf, BF_BLOCK_SIZE*8-1 -recordNum)) { //-> Elegxei ean uparxei i eggrafi pou zitithike.
if (BF_UnpinBlock(fileDesc, blockNum, 0) != BFE_OK) //-> Kanei unpin to block pou efere sti mnimi.
return (HF_errno = HFE_BFERROR); //
return (HF_errno = HFE_INVALIDREC);
}
memcpy(record, blockBuf+recordNum*recordSize, recordSize); //-> Adigrafei tin eggrafi sto 'record'.
if(BF_UnpinBlock(fileDesc, blockNum, 0) != BFE_OK ) //-> Kanei unpin to block pou efere proigoumenws
return (HF_errno = HFE_INVALIDREC); // sti mnimi.
return HFE_OK;
}
int RMM_GetNextRec(int fileDesc, int recId, char *record, int recordSize)
{
int ret, i, max_records, blockNum, startingRec;
char *blockBuf;
if (( blockBuf = malloc(BF_BLOCK_SIZE)) == NULL) {
BF_Errno = BFE_NOMEM;
return (HF_errno = HFE_BFERROR);
}
max_records = BF_BLOCK_SIZE*8 / (recordSize*8 + 1); //-> Ypologizei to megisto plithos eggrafwn
// pou xwraei to kathe block.
blockNum = recId / max_records + 1; //-> Ypologizei poio einai to block sto opoio
// vrisketai i 'recId'-iosti eggrafi.
startingRec = recId % max_records + 1; //-> Vriskei ti thesi tis epomenis eggrafis mesa
// sto block. Ean ksepernaei to 'max_records'
// den einai provlima.
if (BF_GetThisBlock(fileDesc, blockNum, &blockBuf) != BFE_OK ) //-> Fernei stin mnimi to block sto opoio vrisketai
return (HF_errno = HFE_BFERROR); // i eggrafi me anagnwristiko 'recId'.
do { //-> Gia to block pou exei erthei sti mnimi,
for(i = startingRec ; i < max_records; i++) //-> Gia kathe thesi eggrafis tou block
if (isBitActive(blockBuf, BF_BLOCK_SIZE*8-1 -i)) { // ksekinontas apo tin 'startingRec',
// elegxei ean uparxei eggrafi.
memcpy(record, blockBuf+i*recordSize, recordSize); //-> Ean nai, adigrafei tin eggrafi sto
// 'record'.
if (BF_UnpinBlock(fileDesc, blockNum, 0) != BFE_OK) //-> Kanei unpin to block pou exei ferei
return (HF_errno = HFE_BFERROR); // sti mnimi.
return ((blockNum-1)*max_records + i);
}
if (BF_UnpinBlock(fileDesc, blockNum, 0) != BFE_OK) //-> Kanei unpin to block pou exei ferei
return (HF_errno = HFE_BFERROR); // sti mnimi.
startingRec = 0; //-> Thetei tin arxiki thesi anazitisis
// eggrafis enos block se '0' (1i thesi).
} while ((ret = BF_GetNextBlock(fileDesc, &blockNum , &blockBuf)) == BFE_OK ); //-> Den exei vrethei akomi i zitoumeni "epomeni
// eggrafi", ki etsi psaxnei sto epomeno block.
if (ret == BFE_EOF) return (HF_errno = HFE_EOF);
else return (HF_errno = HFE_BFERROR);
}
int BF_GetNextBlock(int fileDesc,int *blockNum,char **blockbuf){
int nobs,i,NumBlock=-1;
if(of_table[fileDesc].isfree==0){
BF_errno=-14;
return BF_errno;//Error -> Lathos fileDesc
}
nobs=of_table[fileDesc].header_ptr->ofhead->num_of_blocks;
for(i=(*blockNum+1);i<nobs;i++){
if(is_valid(of_table[fileDesc].header_ptr->ofhead->bitmaptable,i)==1){
NumBlock=i+1;
break;//Brhka to prwto valid block , meta to dosmeno block , sth thesh i+1
}
}
//Den yparxei valid block sto arxeio meta to dosmeno block
if(NumBlock<0){
BF_errno=-11;
return BF_errno;;
}
*blockNum=NumBlock-1;
//Kalw thn BF_GetThisBlock me orisma to prwto valid block(an yparxei) , meta to dosmeno block , pou exw brei
return BF_GetThisBlock(fileDesc,NumBlock-1,blockbuf);
}
