create

int SHT_CreateSecondaryIndex(char *sfileName, char *attrName, int attrLength, int buckets, char *fileName){

    int result;
    int fileDesc;
    int blockID;
    void* block;
    int i,j = 0;
    SecondaryBlock sblock;


    if (BF_CreateFile(sfileName) < 0) {BF_PrintError("Error creating file");exit(EXIT_FAILURE);}

    if ((fileDesc = BF_OpenFile(sfileName)) < 0) {BF_PrintError("Error opening file");return -1;}

    SHT_info sht_info;
    sht_info.fileDesc = fileDesc;
    sht_info.attrLength = attrLength;
    sht_info.numBuckets = buckets;
    sht_info.attrName = malloc(attrLength*sizeof(char));
    strcpy(sht_info.attrName, attrName);
    sht_info.fileNameLength = (strlen(fileName)+1);
    sht_info.fileName = malloc(sht_info.fileNameLength*sizeof(char));
    strcpy(sht_info.fileName, fileName);

    for(i = 0; i < buckets; ++i)
    {
        if (BF_AllocateBlock(fileDesc) < 0) {BF_PrintError("Error allocating block");return -1;}
        if (BF_ReadBlock(fileDesc, i , &block) < 0) {BF_PrintError("Error getting block");return -1;}
        if (i == 0) {
            for(j=0; j<MAX_BUCKETS; j++) {
                sht_info.buckets[j] = j+1;
                secondaryHashTable[j] = j+1;
            }
            memcpy(block,&sht_info,sizeof(sht_info));
            memcpy(block+sizeof(sht_info),sht_info.attrName,sizeof(char)*attrLength);
            if (BF_WriteBlock(fileDesc, 0) < 0){BF_PrintError("Error writing block back");return -1;}
        }
        else {
            sblock.recordsCounter = 0;
            sblock.nextBlock = -1;
            for(j=0; j<MAX_RECORDS; j++) {
                sblock.bit_array[j] = 0;
            }
            memcpy(block,&sblock,sizeof(Block));
            if (BF_WriteBlock(fileDesc, i) < 0){BF_PrintError("Error writing block back");return -1;}
        }
        if (BF_WriteBlock(fileDesc, i) < 0){BF_PrintError("Error writing block back");return -1;}

    }

    int key;
    Block p_block;
    for(i = 0; i < MAX_BUCKETS; ++i)
    {
        key = primaryHashTable[i];
        while(1)
        {
            if(BF_ReadBlock(primary_fileDesc, key, &block)){BF_PrintError("Error getting block");return -1;}
            p_block = *(Block *)block;
            for(j = 0; j < P_MAX_RECORDS; ++j)
            {
                if(p_block.bit_array[j] != 0)
                {
                    result = findrecord(p_block.records[j].id, "SHT", fileDesc);
                    if(result < 0)
                    {
                        SecondaryRecord sr;
                        sr.blockId = key;
                        sr.record.id = p_block.records[j].id;

                        if(strcmp(sht_info.attrName,"name") == 0)
                            strcpy(sr.record.name, p_block.records[j].name);
                        else if(strcmp(sht_info.attrName,"surname") == 0)
                            strcpy(sr.record.surname, p_block.records[j].surname);
                        else if(strcmp(sht_info.attrName,"address") == 0)
                            strcpy(sr.record.address, p_block.records[j].address);

                        result = SHT_SecondaryInsertEntry(sht_info, sr);
                    }
                }
            }

            if(p_block.next_block != -1)
                key = p_block.next_block;
            else
                break;
        }
    }

    if (BF_CloseFile(fileDesc) < 0) {BF_PrintError("Error closing file");return -1;}
    free(sht_info.attrName);
    free(sht_info.fileName);
    return 0;
}

int findrecord(int id, char *type, int fileDesc)
{
    int result;
    void *block;
    int i = 0;

    int key = hash_integer(id, MAX_BUCKETS);
    if(strcmp(type, "PHT") == 0)
    {
        Block *p_block;
        key = primaryHashTable[key];
        while(1)
        {
            if(BF_ReadBlock(fileDesc, key, &block)<0){BF_PrintError("Error getting block");return -1;}
            p_block = (Block *)block;
            for(i = 0; i < P_MAX_RECORDS; ++i)
            {
                if(p_block->bit_array[i] == 1)
                {
                    if(p_block->records[i].id == id)
                        return key;
                }
            }
            if(p_block->next_block != -1)
                key = p_block->next_block;
            else
                return -1;
        }
    }
    else if(strcmp(type, "SHT") == 0)
    {
        SecondaryBlock *sec_block;

        key = secondaryHashTable[key];
        while(1)
        {
            if(BF_ReadBlock(fileDesc, key, &block)){BF_PrintError("Error getting block");return -1;}
            sec_block = (SecondaryBlock *)block;
            for( i = 0; i < S_MAX_RECORDS; ++i)
            {
                if(sec_block->bit_array[i] == 1)
                {
                    if(sec_block->records[i].recordID == id)
                        return key;
                }
            }
            if(sec_block->nextBlock == -1)
                return -1;
            else
                key = sec_block->nextBlock;
        }
    }
}