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-rw-r--r--kernel/hashlib.h159
1 files changed, 74 insertions, 85 deletions
diff --git a/kernel/hashlib.h b/kernel/hashlib.h
index 5f977c5f..b02abfad 100644
--- a/kernel/hashlib.h
+++ b/kernel/hashlib.h
@@ -17,7 +17,8 @@
namespace hashlib {
-const int config_size_factor = 3;
+const int hashtable_size_trigger = 2;
+const int hashtable_size_factor = 3;
// The XOR version of DJB2
// (traditionally 5381 is used as starting value for the djb2 hash)
@@ -121,37 +122,29 @@ struct hash_obj_ops {
}
};
-inline int hashtable_size(int old_size)
+inline int hashtable_size(int min_size)
{
- // prime numbers, approx. in powers of two
- if (old_size < 53) return 53;
- if (old_size < 113) return 113;
- if (old_size < 251) return 251;
- if (old_size < 503) return 503;
- if (old_size < 1129) return 1129;
- if (old_size < 2503) return 2503;
- if (old_size < 5023) return 5023;
- if (old_size < 11299) return 11299;
- if (old_size < 25097) return 25097;
- if (old_size < 50291) return 50291;
- if (old_size < 112997) return 112997;
- if (old_size < 251003) return 251003;
- if (old_size < 503003) return 503003;
- if (old_size < 1129991) return 1129991;
- if (old_size < 2509993) return 2509993;
- if (old_size < 5029991) return 5029991;
- if (old_size < 11299997) return 11299997;
- if (old_size < 25099999) return 25099999;
- if (old_size < 50299999) return 50299999;
- if (old_size < 113000009) return 113000009;
- if (old_size < 250999999) return 250999999;
- if (old_size < 503000009) return 503000009;
- if (old_size < 1129999999) return 1129999999;
-
- if (sizeof(old_size) == 4)
- throw std::length_error("hash table exceeded maximum size. recompile with -mint64.");
-
- return old_size * 2;
+ static std::vector<int> primes = {
+ 23, 29, 37, 47, 59, 79, 101, 127, 163, 211, 269, 337, 431, 541, 677,
+ 853, 1069, 1361, 1709, 2137, 2677, 3347, 4201, 5261, 6577, 8231, 10289,
+ 12889, 16127, 20161, 25219, 31531, 39419, 49277, 61603, 77017, 96281,
+ 120371, 150473, 188107, 235159, 293957, 367453, 459317, 574157, 717697,
+ 897133, 1121423, 1401791, 1752239, 2190299, 2737937, 3422429, 4278037,
+ 5347553, 6684443, 8355563, 10444457, 13055587, 16319519, 20399411,
+ 25499291, 31874149, 39842687, 49803361, 62254207, 77817767, 97272239,
+ 121590311, 151987889, 189984863, 237481091, 296851369, 371064217
+ };
+
+ for (auto p : primes)
+ if (p > min_size) return p;
+
+ if (sizeof(int) == 4)
+ throw std::length_error("hash table exceeded maximum size. use a ILP64 abi for larger tables.");
+
+ for (auto p : primes)
+ if (100129 * p > min_size) return 100129 * p;
+
+ throw std::length_error("hash table exceeded maximum size.");
}
template<typename K, typename T, typename OPS = hash_ops<K>>
@@ -192,14 +185,12 @@ class dict
entries.clear();
counter = other.size();
- int new_size = hashtable_size(config_size_factor * counter);
- hashtable.resize(new_size);
- new_size = new_size / config_size_factor + 1;
- entries.reserve(new_size);
+ begin_n = counter - 1;
+ entries.reserve(counter);
for (auto &it : other)
entries.push_back(entry_t(it));
- entries.resize(new_size);
+
rehash();
}
@@ -211,18 +202,12 @@ class dict
return hash;
}
- void upd_begin_n()
+ void upd_begin_n(bool do_refree = true)
{
if (begin_n < -1) {
begin_n = -(begin_n+2);
- if (begin_n > int(entries.size()))
- begin_n = int(entries.size());
- do {
- if (begin_seek_count++ > int(entries.size()))
- refree();
- else
- begin_n--;
- } while (begin_n >= 0 && entries[begin_n].is_free());
+ while (begin_n >= 0 && entries[begin_n].is_free()) { begin_seek_count++; begin_n--; }
+ if (do_refree && begin_seek_count > int(entries.size() / 2)) refree();
}
}
@@ -250,11 +235,14 @@ class dict
void rehash()
{
+ upd_begin_n(false);
+ entries.resize(begin_n + 1);
+
free_list = -1;
begin_n = -1;
- for (auto &h : hashtable)
- h = -1;
+ hashtable.clear();
+ hashtable.resize(hashtable_size(entries.size() * hashtable_size_factor), -1);
int last_free = -1;
for (int i = 0; i < int(entries.size()); i++)
@@ -319,15 +307,18 @@ class dict
{
if (free_list < 0)
{
- int i = entries.size();
- int new_size = hashtable_size(config_size_factor * entries.size());
- hashtable.resize(new_size);
- entries.resize(new_size / config_size_factor + 1);
- entries[i].udata = value;
- entries[i].set_next_used(0);
- counter++;
- rehash();
- return i;
+ free_list = entries.size();
+ entries.push_back(entry_t());
+
+ if (entries.size() * hashtable_size_trigger > hashtable.size()) {
+ int i = free_list;
+ entries[i].udata = value;
+ entries[i].set_next_used(0);
+ begin_n = i;
+ counter++;
+ rehash();
+ return i;
+ }
}
int i = free_list;
@@ -384,8 +375,7 @@ public:
dict(dict<K, T, OPS> &&other)
{
- free_list = -1;
- counter = 0;
+ init();
swap(other);
}
@@ -504,6 +494,7 @@ public:
std::swap(free_list, other.free_list);
std::swap(counter, other.counter);
std::swap(begin_n, other.begin_n);
+ std::swap(begin_seek_count, other.begin_seek_count);
}
bool operator==(const dict<K, T, OPS> &other) const {
@@ -579,14 +570,12 @@ class pool
entries.clear();
counter = other.size();
- int new_size = hashtable_size(config_size_factor * counter);
- hashtable.resize(new_size);
- new_size = new_size / config_size_factor + 1;
- entries.reserve(new_size);
+ begin_n = counter - 1;
+ entries.reserve(counter);
for (auto &it : other)
entries.push_back(entry_t(it));
- entries.resize(new_size);
+
rehash();
}
@@ -598,18 +587,12 @@ class pool
return hash;
}
- void upd_begin_n()
+ void upd_begin_n(bool do_refree = true)
{
if (begin_n < -1) {
begin_n = -(begin_n+2);
- if (begin_n > int(entries.size()))
- begin_n = int(entries.size());
- do {
- if (begin_seek_count++ > int(entries.size()))
- refree();
- else
- begin_n--;
- } while (begin_n >= 0 && entries[begin_n].is_free());
+ while (begin_n >= 0 && entries[begin_n].is_free()) { begin_seek_count++; begin_n--; }
+ if (do_refree && begin_seek_count > int(entries.size() / 2)) refree();
}
}
@@ -637,11 +620,14 @@ class pool
void rehash()
{
+ upd_begin_n(false);
+ entries.resize(begin_n + 1);
+
free_list = -1;
begin_n = -1;
- for (auto &h : hashtable)
- h = -1;
+ hashtable.clear();
+ hashtable.resize(hashtable_size(entries.size() * hashtable_size_factor), -1);
int last_free = -1;
for (int i = 0; i < int(entries.size()); i++)
@@ -706,15 +692,18 @@ class pool
{
if (free_list < 0)
{
- int i = entries.size();
- int new_size = hashtable_size(config_size_factor * entries.size());
- hashtable.resize(new_size);
- entries.resize(new_size / config_size_factor + 1);
- entries[i].key = key;
- entries[i].set_next_used(0);
- counter++;
- rehash();
- return i;
+ free_list = entries.size();
+ entries.push_back(entry_t());
+
+ if (entries.size() * hashtable_size_trigger > hashtable.size()) {
+ int i = free_list;
+ entries[i].key = key;
+ entries[i].set_next_used(0);
+ begin_n = i;
+ counter++;
+ rehash();
+ return i;
+ }
}
int i = free_list;
@@ -771,8 +760,7 @@ public:
pool(pool<K, OPS> &&other)
{
- free_list = -1;
- counter = 0;
+ init();
swap(other);
}
@@ -871,6 +859,7 @@ public:
std::swap(free_list, other.free_list);
std::swap(counter, other.counter);
std::swap(begin_n, other.begin_n);
+ std::swap(begin_seek_count, other.begin_seek_count);
}
bool operator==(const pool<K, OPS> &other) const {