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#ifndef hashmap_hpp
#define hashmap_hpp
extern "C" {
#include "plat.h"
}
#include <tuple>
#include <stddef.h>
template <typename T>
struct Hash_Function {};
template <typename Key, typename Value, int size>
struct Hash_Map {
enum {
flags_tombstone = 1 << 0,
flags_null = 1 << 1
};
Key keys[size];
Value values[size];
uint8_t flags[size];
void init() {
int i;
for (i = 0; i < size; i++) flags[i] = flags_null;
}
int find(const Key& to_find) const {
int tombstone = -1, i;
int bucket = (int)(Hash_Function<Key>{}(to_find) % (size_t)size);
for (i = 0; i < size; i++) {
const Key& k = keys[bucket];
uint8_t flag = flags[bucket];
if (flag & flags_null) {
if (flag & flags_tombstone) {
if (tombstone < 0) tombstone = bucket;
} else return tombstone >= 0? tombstone: bucket;
} else if (k == to_find) return bucket;
bucket = (bucket + 1) % size;
}
if (tombstone >= 0) return tombstone;
return -1;
}
Value& set(const Key& k, const Value& v) {
int bucket = find(k);
assert(bucket >= 0); /* full */
flags[bucket] = 0;
keys[bucket] = k;
values[bucket] = v;
return values[bucket];
}
Value* get(const Key& k) {
int bucket = find(k);
if (bucket < 0 || flags[bucket] & flags_null) return 0;
return &values[bucket];
}
Value& operator[](const Key& k) {
int bucket = find(k);
assert(bucket >= 0);
return values[bucket];
}
const Value& operator[](const Key& k) const {
int bucket = find(k);
assert(bucket >= 0);
return values[bucket];
}
Key* kaddr(const Key& k) {
int bucket = find(k);
if (bucket < 0 || flags[bucket] & flags_null) return 0;
return &keys[bucket];
}
void remove(const Key& k) {
int bucket = find(k);
assert(bucket >= 0);
flags[bucket] = flags_null | flags_tombstone;
}
int has(const Key& k) {
int bucket = find(k);
return bucket >= 0 && ~flags[bucket] & flags_null;
}
template <typename Table>
struct iterator {
Table* table;
int bucket;
void init_begin(Table* t) {
bucket = 0;
table = t;
while (
bucket < size &&
table->flags[bucket] & flags_null
) bucket++;
}
void init_end(Table* t) {
bucket = size;
table = t;
}
bool equals(const iterator<Table>& other) {
return bucket == other.bucket && table == other.table;
}
bool operator==(const iterator<Table>& other) {
return equals(other);
}
bool operator!=(const iterator<Table>& other) {
return !equals(other);
}
iterator<Table> operator++() {
bucket++;
while (
bucket < size &&
table->flags[bucket] & flags_null
) bucket++;
return *this;
}
std::pair<Key&, Value&> operator*() {
return { table->keys[bucket], table->values[bucket] };
}
std::pair<const Key&, const Value&> operator*() const {
return { table->keys[bucket], table->values[bucket] };
}
};
iterator<Hash_Map<Key, Value, size>> begin() {
iterator<Hash_Map<Key, Value, size>> r;
r.init_begin(this);
return r;
}
iterator<Hash_Map<Key, Value, size>> end() {
iterator<Hash_Map<Key, Value, size>> r;
r.init_end(this);
return r;
}
iterator<const Hash_Map<Key, Value, size>> begin() const {
iterator<const Hash_Map<Key, Value, size>> r;
r.init_begin(this);
return r;
}
iterator<const Hash_Map<Key, Value, size>> end() const {
iterator<const Hash_Map<Key, Value, size>> r;
r.init_end(this);
return r;
}
};
#endif
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