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#include <stdlib.h>
#include <string.h>
#include "memory.h"
#include "object.h"
#include "table.h"
#include "value.h"
#define TABLE_MAX_LOAD 0.75
void initTable(Table *table) {
table->count = 0;
table->capacity = 0;
table->entries = NULL;
}
void freeTable(Table *table) {
FREE_ARRAY(Entry, table->entries, table->capacity);
initTable(table);
}
static Entry *findEntry(Entry *entries, int capacity, ObjString *key) {
uint32_t index = key->hash % capacity;
Entry *tombstone = NULL;
for (;;) {
Entry *entry = &entries[index];
if (entry->key == NULL) {
if (IS_NIL(entry->value)) {
// Empty entry.
return tombstone != NULL ? tombstone : entry;
} else {
// We found a tombstone.
if (tombstone == NULL)
tombstone = entry;
}
} else if (entry->key == key) {
// We found the entry.
return entry;
}
index = (index + 1) % capacity;
}
}
bool tableGet(Table *table, ObjString *key, Value *value) {
if (table->count == 0)
return false;
Entry *entry = findEntry(table->entries, table->capacity, key);
if (entry->key == NULL)
return false;
*value = entry->value;
return true;
}
static void adjustCapacity(Table *table, int capacity) {
Entry *entries = ALLOCATE(Entry, capacity);
for (int i = 0; i < capacity; i++) {
entries[i].key = NULL;
entries[i].value = NIL_VAL;
}
table->count = 0;
for (int i = 0; i < table->capacity; i++) {
Entry *entry = &table->entries[i];
if (entry->key == NULL)
continue;
Entry *dest = findEntry(entries, capacity, entry->key);
dest->key = entry->key;
dest->value = entry->value;
table->count++;
}
FREE_ARRAY(Entry, table->entries, table->capacity);
table->entries = entries;
table->capacity = capacity;
}
bool tableSet(Table *table, ObjString *key, Value value) {
if (table->count + 1 > table->capacity * TABLE_MAX_LOAD) {
int capacity = GROW_CAPACITY(table->capacity);
adjustCapacity(table, capacity);
}
Entry *entry = findEntry(table->entries, table->capacity, key);
bool isNewKey = entry->key == NULL;
if (isNewKey && IS_NIL(entry->value))
table->count++;
entry->key = key;
entry->value = value;
return isNewKey;
}
bool tableDelete(Table *table, ObjString *key) {
if (table->count == 0)
return false;
/* Find the entry. */
Entry *entry = findEntry(table->entries, table->capacity, key);
if (entry->key == NULL)
return false;
/* Place a tombstone in the entry. */
entry->key = NULL;
entry->value = BOOL_VAL(true);
return true;
}
void tableAddAll(Table *from, Table *to) {
for (int i = 0; i < from->capacity; i++) {
Entry *entry = &from->entries[i];
if (entry->key != NULL) {
tableSet(to, entry->key, entry->value);
}
}
}
ObjString *tableFindString(Table *table, const char *chars, int length,
uint32_t hash) {
if (table->count == 0)
return NULL;
uint32_t index = hash % table->capacity;
for (;;) {
Entry *entry = &table->entries[index];
if (entry->key == NULL) {
/* Stop if we find an empty non-tombstone entry. */
if (IS_NIL(entry->value))
return NULL;
} else if (entry->key->length == length && entry->key->hash == hash
&& memcmp(entry->key->chars, chars, length) == 0) {
/* We found it. */
return entry->key;
}
index = (index + 1) % table->capacity;
}
}
void tableRemoveWhite(Table *table) {
for (int i = 0; i < table->capacity; i++) {
Entry *entry = &table->entries[i];
if (entry->key != NULL && !entry->key->obj.isMarked) {
tableDelete(table, entry->key);
}
}
}
void markTable(Table *table) {
for (int i = 0; i < table->capacity; i++) {
Entry *entry = &table->entries[i];
markObject((Obj *)entry->key);
markValue(entry->value);
}
}
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