/**
* Searches and retrieves matches using the values from the param
*
* @param {string[]} Array of items to search for
* @returns {string[]} Results of the search in an array, which can be used to write to a file
* @api public
*/
public string[] Search(string[] searches)
{
bool found;
int bucket_no;
int slot_no;
List<String> lines = new List<String>();
lines.Add(String.Format("{0,45}", "Search and Retrieval Report"));
lines.Add(String.Format("{0,38}", "Transactions"));
lines.Add(String.Format("{0,37}", "Search Key\t\tBucket/Slot\t\tRecord"));
foreach (string keys in searches)
{
// hashed key
string key = this.Hash(keys.Substring(0, 10));
found = false;
bucket_no = 0;
foreach (Bucket item in this.table)
{
slot_no = 0;
foreach(Dictionary<string, Slot> dict in item.slots)
{
foreach (KeyValuePair<string, Slot> kv in item.slots[slot_no])
{
// if the two un-hashed keys are equal
if (item.slots[slot_no][kv.Key].key == keys.Substring(0, 10))
{
// found
found = true;
lines.Add(String.Format("{0,16}{1,16}/{2}\t\t{3}", item.slots[slot_no][kv.Key].key,
bucket_no + 1,
slot_no + 1,
item.slots[slot_no][kv.Key].value
));
}
}
// manual iteration
++slot_no;
}
// manual iteration
++bucket_no;
}
// if nothing was found
if (!found)
{
lines.Add(String.Format("{0,16}{1,16}/{2,0}\t\t{3,0}",
keys.Substring(0, 10),
"N",
"A",
"Record not found"
));
}
}
return lines.ToArray();
}
/**
* Collect bucket statistics
*
* @returns {string[]} Array of strings that can be written to a file
* @api public
*/
public string[] CollectStatistics()
{
List<string> lines = new List<string>();
List<int> chain = new List<int>();
Dictionary<int, int> chain_count = new Dictionary<int, int>();
float chain_avg = 0F;
float total_length_avg = 0F;
float total_length = 0F;
float non_zero_length_buckets = 0F;
for (int i = 20; i < MAX_BUCKETS; ++i)
{
// if overflow is set
if (this.table[i].overflow != -1)
{
// if overflow is greater than table size, do some weird math stuff.
// this accounts for overflows of overflows.
// else add to the list normally.
if (this.table[i].overflow + 1 >= PRIMARY_TABLE_SIZE)
{
chain.Add((this.table[i].overflow + 1) - (PRIMARY_TABLE_SIZE - 1));
}
else
{
chain.Add(this.table[i].overflow + 1);
}
}
else
{
//if no overflow is set, just add 0 (not -1)
chain.Add(0);
}
// if the chain_count dicitionary contains this key and overflow is also set
if (!chain_count.ContainsKey(i) && this.table[i].overflow != -1)
{
// ternary statement. this math accounts for overflow of overflows.
int index = (this.table[i].overflow + 1 >= PRIMARY_TABLE_SIZE) ?
(this.table[i].overflow + 1) - (PRIMARY_TABLE_SIZE - 1) : this.table[i].overflow + 1;
// counts number of instance index appears in the dictionary
chain_count[index] = chain.Count(v => v == index);
// add to the collission chain average
chain_avg += chain_count[index];
}
}
// calculate the collission chain avrage
chain_avg /= chain_count.Count();
for (int i = 0; i < PRIMARY_TABLE_SIZE; ++i)
{
// grab the total length of each bucket
total_length += this.table[i].count;
// write to the list, which then will be returned and can be used to write to a file.
lines.Add("Bucket " + (i + 1) + ":");
lines.Add("\tTotal Length: " + this.table[i].count);
lines.Add("\n");
// if count is greater than 1,
// +1 to the number of buckets which have a more than one slot filled
// the requirements state not to cound zero length buckets in the average caluclations
if (this.table[i].count != 0)
{
++non_zero_length_buckets;
}
}
// calculate the average total length of all primary buckets
total_length_avg = total_length / non_zero_length_buckets;
lines.Add("Total Length Average is " + total_length_avg);
lines.Add("Collission Chain Average is " + chain_avg);
return lines.ToArray();
}
/**
* Generates a report for of the Hash Table contents
*
* @returns {string[]} A string array which can be written to a file.
* @api public
*/
public string[] GenerateReport()
{
List<String> lines = new List<String>();
int table_no = 0;
int slot_no;
lines.Add(String.Format("{0, 37}", "Hash Table"));
lines.Add(String.Format("{0, 41}", "Verification Report"));
lines.Add(String.Format("{0, 39}", "Before Report"));
foreach (Bucket item in this.table)
{
lines.Add(String.Format("Bucket {0}", table_no + 1));
slot_no = 0;
foreach (Dictionary<string, Slot> dict in item.slots)
{
foreach (KeyValuePair<string, Slot> kv in item.slots[slot_no])
{
// if there is a key in the slot
if (item.slots[slot_no][kv.Key].key != null)
{
lines.Add(String.Format("\tSlot {0}: {1}{2}",
slot_no + 1,
item.slots[slot_no][kv.Key].key,
item.slots[slot_no][kv.Key].value
));
}
}
// there must be no key
if (item.slots[slot_no].Count == 0)
{
lines.Add(String.Format("\tSlot {0}: None", slot_no + 1));
}
// manual iteration
++slot_no;
}
// if an overflow pointer is set
if (this.table[table_no].overflow != -1)
{
lines.Add(String.Format("\tOverflow Pointer: {0}", this.table[table_no].overflow + 1));
}
else
{
lines.Add(String.Format("\tOveflow Pointer: {0}", "None"));
}
lines.Add(String.Format("{0}", "\n"));
// manual iteration
++table_no;
}
return lines.ToArray();
}
