int RMM_GetFirstRec(int fileDesc, char *record, int recordSize)
{
int max_records, blockNum, i;
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 = 0; //-> Tha psaksei na vrei to 1o eguro block
// meta to 'block 0' dld meta to HF_HEADER.
if(BF_GetNextBlock(fileDesc, &blockNum, &blockBuf) != BFE_OK ) //-> Fernei to prwto block pou vrei me estw mia
return (HF_errno = HFE_BFERROR); // eggrafi.
for(i=0 ; i < max_records ; i++) //-> Gia kathe thesi eggrafis sto block, koitaei
if(isBitActive(blockBuf, BF_BLOCK_SIZE*8-1 -i)) { // ean uparxei eggrafi.
memcpy(record, blockBuf+i*recordSize, recordSize); //-> Ean nai, adigrafei tin eggrafi stin 'record'.
break; //
}
if (BF_UnpinBlock(fileDesc, blockNum, 0 ) != BFE_OK ) //-> Kanei unpin to block pou efere sti mnimi.
return (HF_errno = HFE_BFERROR);
return ((blockNum-1)*max_records + i);
}
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 main()
{
int athletesFd;
int athletesBlockNum;
char *athletesBlockBuf;
int athleteId;
char athleteName[BF_MAIN_NAME_SIZE];
char athleteSurName[BF_MAIN_NAME_SIZE];
/* Αρχικοποίηση του επιπέδου αρχείου μπλοκ */
BF_Init();
/* ’νοιγμα του αρχείου ATHLETES */
athletesFd = BF_OpenFile("ATHLETES");
if (athletesFd < 0)
{
BF_PrintError("Error in BF_OpenFile called on ATHLETES.");
return;
}
/* Εκτύπωση όλων των αθλητών */
if (BF_GetFirstBlock(athletesFd, &athletesBlockNum, &athletesBlockBuf) != BFE_OK)
BF_PrintError("Error in BF_GetFirstBlock called on ATHLETES.");
printf("File ATHLETES contains the following athletes:\nID NAME\n--- ----------------------------\n");
do
{
int i;
for (i = 0; i < BF_MAIN_MAX_NUM_OF_RECS; i++)
{
athleteId = * (int *) athletesBlockBuf;
athletesBlockBuf += sizeof(int);
strcpy(athleteName, athletesBlockBuf);
athletesBlockBuf += BF_MAIN_NAME_SIZE;
strcpy(athleteSurName, athletesBlockBuf);
athletesBlockBuf += BF_MAIN_NAME_SIZE;
if (strlen(athleteName) == 0) break;
printf("%03d %s %s\n", athleteId, athleteName, athleteSurName);
}
BF_UnpinBlock(athletesFd, athletesBlockNum, FALSE);
} while(BF_GetNextBlock(athletesFd, &athletesBlockNum, &athletesBlockBuf) == BFE_OK);
printf("\n**********************\n\n");
/* Κλείσιμο του αρχείου ATHLETES. */
if (BF_CloseFile(athletesFd) < 0)
BF_PrintError("Error in BF_CloseFile called on ATHLETES.");
/* Σβήσιμο των τριών αρχείων */
if (BF_DestroyFile("EVENTS") != BFE_OK)
BF_PrintError("Error in BF_DestroyFile called on EVENTS.");
else printf("File EVENTS successfully destroyed.\n");
if (BF_DestroyFile("ATHLETES") != BFE_OK)
BF_PrintError("Error in BF_DestroyFile called on ATHLETES.");
else printf("File ATHLETES successfully destroyed.\n");
if (BF_DestroyFile("PARTICIPATIONS") != BFE_OK)
BF_PrintError("Error in BF_DestroyFile called on PARTICIPATIONS.");
else printf("File PARTICIPATIONS successfully destroyed.\n");
return 0;
}
