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#include <string>
#include <iostream>
#include <assert.h>
#include <math.h>
#include <aterm2.h>
using namespace std;
class ATermMap
{
private:
struct KeyValue
{
ATerm key;
ATerm value;
};
/* Hash table for the map. We use open addressing, i.e., all
key/value pairs are stored directly in the table, and there are
no pointers. Collisions are resolved through probing. */
KeyValue * hashTable;
/* Current size of the hash table. */
unsigned int size;
/* Number of elements in the hash table. */
unsigned int count;
/* Maximum number of elements in the hash table. If `count'
exceeds this number, the hash table is expanded. */
unsigned int maxCount;
public:
/* Create a map. `expectedCount' is the number of elements the
map is expected to hold. */
ATermMap(unsigned int expectedCount);
ATermMap(const ATermMap & map);
~ATermMap();
ATermMap & operator = (const ATermMap & map);
void set(ATerm key, ATerm value);
ATerm get(ATerm key) const;
void remove(ATerm key);
void remove(const string & key);
private:
void init(unsigned int expectedCount);
void resizeTable(unsigned int expectedCount);
unsigned int hash1(ATerm key) const;
unsigned int hash2(ATerm key) const;
};
ATermMap::ATermMap(unsigned int expectedCount)
{
init(expectedCount);
}
ATermMap::~ATermMap()
{
if (hashTable) free(hashTable);
}
void ATermMap::init(unsigned int expectedCount)
{
size = 0;
count = 0;
maxCount = 0;
hashTable = 0;
resizeTable(expectedCount);
}
void ATermMap::resizeTable(unsigned int expectedCount)
{
assert(size == 0);
this->maxCount = expectedCount;
unsigned int newSize = 128;
hashTable = (KeyValue *) calloc(sizeof(KeyValue), newSize);
size = newSize;
}
unsigned int ATermMap::hash1(ATerm key) const
{
/* Don't care about the least significant bits of the ATerm
pointer since they're always 0. */
unsigned int key2 = ((unsigned int) key) >> 2;
#if 0
double d1 = key2 * 0.6180339887;
unsigned int h1 = (int) (size * (d1 - floor(d1)));
#endif
#if 0
unsigned int h1 = size * (key2 * 61803 % 100000);
#endif
unsigned int h1 = (size * ((key2 * 40503) & 0xffff)) >> 16;
// cout << key2 << " " << h1 << endl;
// unsigned int h1 = (key2 * 134217689) & (size - 1);
return h1 % size;
}
unsigned int ATermMap::hash2(ATerm key) const
{
unsigned int key2 = ((unsigned int) key) >> 2;
#if 0
double d2 = key2 * 0.6180339887;
unsigned int h2 = 1 | (int) (size * (d2 - floor(d2)));
#endif
unsigned int h3 = ((key2 * 134217689) & (size - 1)) | 1;
return h3;
}
unsigned int nrItemsSet = 0;
unsigned int nrSetProbes = 0;
unsigned int nrMaxProbes = 0;
void ATermMap::set(ATerm key, ATerm value)
{
unsigned int probes = 0;
nrItemsSet++;
for (unsigned int i = 0, h = hash1(key); i < size;
++i, h = (h + hash2(key)) & (size - 1))
{
assert(h < size);
probes++;
nrSetProbes++;
if (hashTable[h].key == 0) {
if (probes > nrMaxProbes) nrMaxProbes = probes;
hashTable[h].key = key;
hashTable[h].value = value;
count++;
return;
}
}
abort();
}
unsigned int nrItemsGet = 0;
unsigned int nrGetProbes = 0;
ATerm ATermMap::get(ATerm key) const
{
nrItemsGet++;
for (unsigned int i = 0, h = hash1(key); i < size;
++i, h = (h + hash2(key)) & (size - 1))
{
nrGetProbes++;
if (hashTable[h].key == 0) return 0;
if (hashTable[h].key == key) return hashTable[h].value;
}
return 0;
}
int main(int argc, char * * argv)
{
ATerm bottomOfStack;
ATinit(argc, argv, &bottomOfStack);
/* Make test terms. */
int nrTestTerms = 100000;
ATerm testTerms[nrTestTerms];
for (int i = 0; i < nrTestTerms; ++i) {
char name[10];
sprintf(name, "%d", (int) random() % 37);
int arity = i == 0 ? 0 : (random() % 37);
ATerm kids[arity];
for (int j = 0; j < arity; ++j)
kids[j] = testTerms[random() % i];
testTerms[i] = (ATerm) ATmakeApplArray(ATmakeAFun(name, arity, ATfalse), kids);
// ATwriteToSharedTextFile(testTerms[i], stdout);
// printf("\n");
}
cout << "testing...\n";
#define someTerm() (testTerms[(int) random() % nrTestTerms])
for (int test = 0; test < 100000; ++test) {
ATermMap map(100);
for (int i = 0; i < 30; ++i)
map.set(someTerm(), someTerm());
for (int i = 0; i < 100; ++i)
map.get(someTerm());
}
cout << "SET: "
<< nrItemsSet << " "
<< nrSetProbes << " "
<< (double) nrSetProbes / nrItemsSet << " "
<< nrMaxProbes << endl;
cout << "GET: "
<< nrItemsGet << " "
<< nrGetProbes << " "
<< (double) nrGetProbes / nrItemsGet << endl;
}
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