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-rw-r--r--src/libutil/Makefile.am3
-rw-r--r--src/libutil/aterm-map.cc312
-rw-r--r--src/libutil/aterm-map.hh114
3 files changed, 428 insertions, 1 deletions
diff --git a/src/libutil/Makefile.am b/src/libutil/Makefile.am
index 9d71b66e6..e10477deb 100644
--- a/src/libutil/Makefile.am
+++ b/src/libutil/Makefile.am
@@ -1,7 +1,8 @@
lib_LTLIBRARIES = libutil.la
libutil_la_SOURCES = util.cc util.hh hash.cc hash.hh \
- archive.cc archive.hh aterm.cc aterm.hh
+ archive.cc archive.hh aterm.cc aterm.hh \
+ aterm-map.cc aterm-map.hh
if !HAVE_OPENSSL
libutil_la_SOURCES += \
diff --git a/src/libutil/aterm-map.cc b/src/libutil/aterm-map.cc
new file mode 100644
index 000000000..e0cfefa2d
--- /dev/null
+++ b/src/libutil/aterm-map.cc
@@ -0,0 +1,312 @@
+#include "aterm-map.hh"
+
+#include <assert.h>
+#include <stdlib.h>
+
+
+static const unsigned int maxLoadFactor = /* 1 / */ 3;
+static unsigned int nrResizes = 0;
+static unsigned int sizeTotalAlloc = 0;
+static unsigned int sizeCurAlloc = 0;
+static unsigned int sizeMaxAlloc = 0;
+
+
+ATermMap::ATermMap(unsigned int expectedCount)
+{
+ init(expectedCount);
+}
+
+
+ATermMap::ATermMap(const ATermMap & map)
+{
+ init(map.maxCount);
+ copy(map.hashTable, map.capacity);
+}
+
+
+ATermMap & ATermMap::operator = (const ATermMap & map)
+{
+ if (this == &map) return *this;
+ free();
+ init(map.maxCount);
+ copy(map.hashTable, map.capacity);
+ return *this;
+}
+
+
+ATermMap::~ATermMap()
+{
+ free();
+}
+
+
+void ATermMap::init(unsigned int expectedCount)
+{
+ assert(sizeof(ATerm) * 2 == sizeof(KeyValue));
+ capacity = 0;
+ count = 0;
+ maxCount = 0;
+ hashTable = 0;
+ resizeTable(expectedCount);
+}
+
+
+void ATermMap::free()
+{
+ if (hashTable) {
+ ATunprotectArray((ATerm *) hashTable);
+ ::free(hashTable);
+ sizeCurAlloc -= sizeof(KeyValue) * capacity;
+ hashTable = 0;
+ }
+}
+
+
+static unsigned int roundToPowerOf2(unsigned int x)
+{
+ x--;
+ x |= x >> 1; x |= x >> 2; x |= x >> 4; x |= x >> 8; x |= x >> 16;
+ x++;
+ return x;
+}
+
+
+void ATermMap::resizeTable(unsigned int expectedCount)
+{
+ if (expectedCount == 0) expectedCount = 1;
+// cout << maxCount << " -> " << expectedCount << endl;
+// cout << maxCount << " " << size << endl;
+// cout << (double) size / maxCount << endl;
+
+ unsigned int oldCapacity = capacity;
+ KeyValue * oldHashTable = hashTable;
+
+ maxCount = expectedCount;
+ capacity = roundToPowerOf2(maxCount * maxLoadFactor);
+ hashTable = (KeyValue *) calloc(sizeof(KeyValue), capacity);
+ sizeTotalAlloc += sizeof(KeyValue) * capacity;
+ sizeCurAlloc += sizeof(KeyValue) * capacity;
+ if (sizeCurAlloc > sizeMaxAlloc) sizeMaxAlloc = sizeCurAlloc;
+ ATprotectArray((ATerm *) hashTable, capacity * 2);
+
+// cout << capacity << endl;
+
+ /* Re-hash the elements in the old table. */
+ if (oldCapacity != 0) {
+ count = 0;
+ copy(oldHashTable, oldCapacity);
+ ATunprotectArray((ATerm *) oldHashTable);
+ ::free(oldHashTable);
+ sizeCurAlloc -= sizeof(KeyValue) * oldCapacity;
+ nrResizes++;
+ }
+}
+
+
+void ATermMap::copy(KeyValue * elements, unsigned int capacity)
+{
+ for (unsigned int i = 0; i < capacity; ++i)
+ if (elements[i].value) /* i.e., non-empty, non-deleted element */
+ set(elements[i].key, elements[i].value);
+}
+
+
+static const unsigned int shift = 16;
+static const unsigned int knuth = (unsigned int) (0.6180339887 * (1 << shift));
+
+
+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;
+
+ /* Approximately equal to:
+ double d = key2 * 0.6180339887;
+ unsigned int h = (int) (capacity * (d - floor(d)));
+ */
+
+ unsigned int h = (capacity * ((key2 * knuth) & ((1 << shift) - 1))) >> shift;
+
+ return h;
+}
+
+
+unsigned int ATermMap::hash2(ATerm key) const
+{
+ unsigned int key2 = ((unsigned int) key) >> 2;
+ /* Note: the result must be relatively prime to `capacity' (which
+ is a power of 2), so we make sure that the result is always
+ odd. */
+ unsigned int h = ((key2 * 134217689) & (capacity - 1)) | 1;
+ return h;
+}
+
+
+static unsigned int nrItemsSet = 0;
+static unsigned int nrSetProbes = 0;
+
+
+void ATermMap::set(ATerm key, ATerm value)
+{
+ if (count == maxCount) resizeTable(capacity * 2 / maxLoadFactor);
+
+ nrItemsSet++;
+ for (unsigned int i = 0, h = hash1(key); i < capacity;
+ ++i, h = (h + hash2(key)) & (capacity - 1))
+ {
+ // assert(h < capacity);
+ nrSetProbes++;
+ /* Note: to see whether a slot is free, we check
+ hashTable[h].value, not hashTable[h].key, since we use
+ value == 0 to mark deleted slots. */
+ if (hashTable[h].value == 0 || hashTable[h].key == key) {
+ if (hashTable[h].value == 0) count++;
+ hashTable[h].key = key;
+ hashTable[h].value = value;
+ return;
+ }
+ }
+
+ abort();
+}
+
+
+static unsigned int nrItemsGet = 0;
+static unsigned int nrGetProbes = 0;
+
+
+ATerm ATermMap::get(ATerm key) const
+{
+ nrItemsGet++;
+ for (unsigned int i = 0, h = hash1(key); i < capacity;
+ ++i, h = (h + hash2(key)) & (capacity - 1))
+ {
+ nrGetProbes++;
+ if (hashTable[h].key == 0) return 0;
+ if (hashTable[h].key == key) return hashTable[h].value;
+ }
+ return 0;
+}
+
+
+void ATermMap::remove(ATerm key)
+{
+ for (unsigned int i = 0, h = hash1(key); i < capacity;
+ ++i, h = (h + hash2(key)) & (capacity - 1))
+ {
+ if (hashTable[h].key == 0) return;
+ if (hashTable[h].key == key) {
+ if (hashTable[h].value != 0) {
+ hashTable[h].value = 0;
+ count--;
+ }
+ return;
+ }
+ }
+}
+
+
+unsigned int ATermMap::size()
+{
+ return count; /* STL nomenclature */
+}
+
+
+#if 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) {
+ //cerr << test << endl;
+ unsigned int n = 300;
+ ATermMap map(300);
+ ATerm keys[n], values[n];
+ for (unsigned int i = 0; i < n; ++i) {
+ keys[i] = someTerm();
+ values[i] = someTerm();
+ map.set(keys[i], values[i]);
+ //cerr << "INSERT: " << keys[i] << " " << values[i] << endl;
+ }
+
+ unsigned int size = map.size();
+ assert(size <= n);
+ values[n - 1] = 0;
+ map.remove(keys[n - 1]);
+ assert(map.size() == size - 1);
+
+ unsigned int checksum;
+ unsigned int count = 0;
+ for (ATermMap::const_iterator i = map.begin(); i != map.end(); ++i, ++count) {
+ assert(i->key);
+ assert(i->value);
+ checksum += (unsigned int) (*i).key;
+ checksum += (unsigned int) (*i).value;
+ // cout << (*i).key << " " << (*i).value << endl;
+ }
+ assert(count == size - 1);
+
+ for (unsigned int i = 0; i < n; ++i) {
+ for (unsigned int j = i + 1; j < n; ++j)
+ if (keys[i] == keys[j]) goto x;
+ if (map.get(keys[i]) != values[i]) {
+ cerr << "MISMATCH: " << keys[i] << " " << values[i] << " " << map.get(keys[i]) << " " << i << endl;
+ abort();
+ }
+ if (values[i] != 0) {
+ checksum -= (unsigned int) keys[i];
+ checksum -= (unsigned int) values[i];
+ }
+ x: ;
+ }
+
+ assert(checksum == 0);
+
+ for (unsigned int i = 0; i < 100; ++i)
+ map.get(someTerm());
+
+ }
+
+ cout << "RESIZES: " << nrResizes << " "
+ << sizeTotalAlloc << " "
+ << sizeCurAlloc << " "
+ << sizeMaxAlloc << endl;
+
+ cout << "SET: "
+ << nrItemsSet << " "
+ << nrSetProbes << " "
+ << (double) nrSetProbes / nrItemsSet << endl;
+
+ cout << "GET: "
+ << nrItemsGet << " "
+ << nrGetProbes << " "
+ << (double) nrGetProbes / nrItemsGet << endl;
+}
+#endif
diff --git a/src/libutil/aterm-map.hh b/src/libutil/aterm-map.hh
new file mode 100644
index 000000000..d7aed2ca2
--- /dev/null
+++ b/src/libutil/aterm-map.hh
@@ -0,0 +1,114 @@
+#ifndef __ATERM_MAP_H
+#define __ATERM_MAP_H
+
+#include <aterm2.h>
+#include <assert.h>
+
+using namespace std;
+
+
+class ATermMap
+{
+public:
+
+ struct KeyValue
+ {
+ ATerm key;
+ ATerm value;
+ };
+
+private:
+
+ /* 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 capacity;
+
+ /* 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);
+
+ unsigned int size();
+
+ struct const_iterator
+ {
+ const ATermMap & map;
+ unsigned int pos;
+ const_iterator(const ATermMap & map, int pos) : map(map)
+ {
+ this->pos = pos;
+ }
+ bool operator !=(const const_iterator & i)
+ {
+ return pos != i.pos;
+ }
+ void operator ++()
+ {
+ if (pos == map.capacity) return;
+ do { ++pos;
+ } while (pos < map.capacity && map.hashTable[pos].value == 0);
+ }
+ const KeyValue & operator *()
+ {
+ assert(pos < map.capacity);
+ return map.hashTable[pos];
+ }
+ const KeyValue * operator ->()
+ {
+ assert(pos < map.capacity);
+ return &map.hashTable[pos];
+ }
+ };
+
+ const_iterator begin() const
+ {
+ unsigned int i = 0;
+ while (i < capacity && hashTable[i].value == 0) ++i;
+ return const_iterator(*this, i);
+ }
+
+ const_iterator end() const
+ {
+ return const_iterator(*this, capacity);
+ }
+
+private:
+
+ void init(unsigned int expectedCount);
+
+ void free();
+
+ void resizeTable(unsigned int expectedCount);
+
+ void copy(KeyValue * elements, unsigned int capacity);
+
+ inline unsigned int hash1(ATerm key) const;
+ inline unsigned int hash2(ATerm key) const;
+};
+
+
+#endif /* !__ATERM_MAP_H */
generated by cgit v1.2.3 (git 2.25.1) at 2024-11-23 23:43:02 +0000