From ec7c66794b993fd6a0c6db8795f8508df84e23c3 Mon Sep 17 00:00:00 2001
From: Clement Sibille <clements+git@lisible.xyz>
Date: Mon, 20 May 2024 01:26:03 +0900
Subject: Add hash module

---
 src/lisiblestd/hash.c | 353 ++++++++++++++++++++++++++++++++++++++++++++++++++
 src/lisiblestd/hash.h |  72 ++++++++++
 2 files changed, 425 insertions(+)
 create mode 100644 src/lisiblestd/hash.c
 create mode 100644 src/lisiblestd/hash.h

(limited to 'src/lisiblestd')

diff --git a/src/lisiblestd/hash.c b/src/lisiblestd/hash.c
new file mode 100644
index 0000000..46ce323
--- /dev/null
+++ b/src/lisiblestd/hash.c
@@ -0,0 +1,353 @@
+#include "hash.h"
+#include "assert.h"
+#include <stddef.h>
+#include <string.h>
+
+void HashTable_noop_dctor_fn(Allocator *allocator, void *v) {
+  (void)allocator;
+  (void)v;
+}
+bool HashTable_init(Allocator *allocator, HashTable *hash_table,
+                    const size_t initial_capacity,
+                    HashTableKeyHashFn key_hash_fn,
+                    HashTableKeyEqFn key_eq_fn) {
+  LSTD_ASSERT(allocator != NULL);
+  LSTD_ASSERT(hash_table != NULL);
+  hash_table->items = Allocator_allocate_array(allocator, initial_capacity,
+                                               sizeof(HashTableKV));
+  if (!hash_table->items) {
+    return false;
+  }
+
+  hash_table->allocator = allocator;
+  hash_table->capacity = initial_capacity;
+  hash_table->length = 0;
+  hash_table->key_hash_fn = key_hash_fn;
+  hash_table->key_eq_fn = key_eq_fn;
+  hash_table->key_dctor_fn = HashTable_noop_dctor_fn;
+  hash_table->value_dctor_fn = HashTable_noop_dctor_fn;
+  return true;
+}
+
+bool HashTable_init_with_dctors(Allocator *allocator, HashTable *hash_table,
+                                const size_t initial_capacity,
+                                HashTableKeyHashFn key_hash_fn,
+                                HashTableKeyEqFn key_eq_fn,
+                                HashTableDctorFn key_dctor_fn,
+                                HashTableDctorFn value_dctor_fn) {
+  LSTD_ASSERT(hash_table != NULL);
+  if (!HashTable_init(allocator, hash_table, initial_capacity, key_hash_fn,
+                      key_eq_fn)) {
+    return false;
+  }
+  hash_table->key_dctor_fn = key_dctor_fn;
+  hash_table->value_dctor_fn = value_dctor_fn;
+  return true;
+}
+
+void HashTable_deinit(HashTable *hash_table) {
+  LSTD_ASSERT(hash_table != NULL);
+  HashTable_clear(hash_table);
+  Allocator_free(hash_table->allocator, hash_table->items);
+}
+
+static size_t HashTable_index_for_key(const HashTable *hash_table,
+                                      const void *key) {
+  LSTD_ASSERT(hash_table != NULL);
+  LSTD_ASSERT(key != NULL);
+  uint64_t hashed_key = hash_table->key_hash_fn(key);
+  return hashed_key % hash_table->capacity;
+}
+
+bool HashTable_expand(HashTable *hash_table) {
+  LSTD_ASSERT(hash_table != NULL);
+  size_t new_capacity = hash_table->capacity * 2;
+
+  // Checking for eventual overflow
+  if (new_capacity < hash_table->capacity) {
+    return false;
+  }
+
+  HashTableKV *new_items = Allocator_allocate_array(
+      hash_table->allocator, new_capacity, sizeof(HashTableKV));
+  if (!new_items) {
+    return false;
+  }
+
+  for (size_t i = 0; i < hash_table->capacity; i++) {
+    HashTableKV *item = &hash_table->items[i];
+    if (item->is_present) {
+      uint64_t key_hash = hash_table->key_hash_fn(item->key);
+      size_t new_index = key_hash % new_capacity;
+      bool found = false;
+      while (new_items[new_index].is_present) {
+        if (hash_table->key_eq_fn(new_items[new_index].key, item->key)) {
+          new_items[new_index].value = item->value;
+          found = true;
+          break;
+        }
+
+        new_index++;
+        if (new_index >= new_capacity) {
+          new_index = 0;
+        }
+      }
+
+      if (!found) {
+        new_items[new_index].key = item->key;
+        new_items[new_index].value = item->value;
+        new_items[new_index].is_present = true;
+      }
+    }
+  }
+
+  Allocator_free(hash_table->allocator, hash_table->items);
+  hash_table->items = new_items;
+  hash_table->capacity = new_capacity;
+  return true;
+}
+
+bool HashTable_insert(HashTable *hash_table, void *key, void *value) {
+  LSTD_ASSERT(hash_table != NULL);
+  LSTD_ASSERT(key != NULL);
+
+  if (hash_table->length >= hash_table->capacity / 2) {
+    if (!HashTable_expand(hash_table)) {
+      return false;
+    }
+  }
+
+  size_t index = HashTable_index_for_key(hash_table, key);
+  while (hash_table->items[index].is_present) {
+    if (hash_table->key_eq_fn(hash_table->items[index].key, key)) {
+      hash_table->items[index].value = value;
+      return true;
+    }
+    index++;
+    if (index >= hash_table->capacity) {
+      index = 0;
+    }
+  }
+
+  hash_table->items[index].key = key;
+  hash_table->items[index].value = value;
+  hash_table->items[index].is_present = true;
+  hash_table->length++;
+  return true;
+}
+
+void *HashTable_get(const HashTable *hash_table, const void *key) {
+  LSTD_ASSERT(hash_table != NULL);
+  LSTD_ASSERT(key != NULL);
+  size_t index = HashTable_index_for_key(hash_table, key);
+  while (hash_table->items[index].is_present) {
+    if (hash_table->key_eq_fn(hash_table->items[index].key, key)) {
+      return hash_table->items[index].value;
+    }
+    index++;
+    if (index >= hash_table->capacity) {
+      index = 0;
+    }
+  }
+
+  return NULL;
+}
+
+bool HashTable_has(const HashTable *hash_table, const void *key) {
+  LSTD_ASSERT(hash_table != NULL);
+  LSTD_ASSERT(key != NULL);
+  size_t index = HashTable_index_for_key(hash_table, key);
+  while (hash_table->items[index].is_present) {
+    if (hash_table->key_eq_fn(hash_table->items[index].key, key)) {
+      return true;
+    }
+    index++;
+    if (index >= hash_table->capacity) {
+      index = 0;
+    }
+  }
+
+  return false;
+}
+
+size_t HashTable_length(const HashTable *hash_table) {
+  LSTD_ASSERT(hash_table != NULL);
+  return hash_table->length;
+}
+
+void HashTable_steal(HashTable *hash_table, const void *key) {
+  LSTD_ASSERT(hash_table != NULL);
+  LSTD_ASSERT(key != NULL);
+  size_t index = HashTable_index_for_key(hash_table, key);
+  while (hash_table->items[index].is_present) {
+    if (hash_table->key_eq_fn(hash_table->items[index].key, key)) {
+      hash_table->key_dctor_fn(hash_table->allocator,
+                               hash_table->items[index].key);
+      hash_table->items[index].key = NULL;
+      hash_table->items[index].value = NULL;
+      hash_table->items[index].is_present = false;
+      break;
+    }
+    index++;
+    if (index >= hash_table->capacity) {
+      index = 0;
+    }
+  }
+  hash_table->length--;
+}
+void HashTable_clear(HashTable *hash_table) {
+  LSTD_ASSERT(hash_table != NULL);
+
+  for (size_t i = 0; i < hash_table->capacity; i++) {
+    if (hash_table->items[i].is_present) {
+      hash_table->key_dctor_fn(hash_table->allocator, hash_table->items[i].key);
+      hash_table->value_dctor_fn(hash_table->allocator,
+                                 hash_table->items[i].value);
+      hash_table->items[i].is_present = false;
+    }
+  }
+
+  hash_table->length = 0;
+}
+
+bool HashSet_init(Allocator *allocator, HashSet *hash_set,
+                  const size_t initial_capacity, HashTableKeyHashFn hash_fn,
+                  HashTableKeyEqFn eq_fn) {
+  LSTD_ASSERT(allocator != NULL);
+  LSTD_ASSERT(hash_set != NULL);
+  return HashTable_init(allocator, hash_set, initial_capacity, hash_fn, eq_fn);
+}
+bool HashSet_init_with_dctor(Allocator *allocator, HashSet *hash_set,
+                             const size_t initial_capacity,
+                             HashTableKeyHashFn hash_fn, HashTableKeyEqFn eq_fn,
+                             HashTableDctorFn dctor_fn) {
+  LSTD_ASSERT(allocator != NULL);
+  LSTD_ASSERT(hash_set != NULL);
+  return HashTable_init_with_dctors(allocator, hash_set, initial_capacity,
+                                    hash_fn, eq_fn, dctor_fn,
+                                    HashTable_noop_dctor_fn);
+}
+void HashSet_deinit(HashSet *hash_set) {
+  LSTD_ASSERT(hash_set != NULL);
+  HashTable_deinit(hash_set);
+}
+bool HashSet_insert(HashSet *hash_set, void *set_value) {
+  LSTD_ASSERT(hash_set != NULL);
+  return HashTable_insert(hash_set, set_value, NULL);
+}
+bool HashSet_has(const HashSet *hash_set, const void *set_value) {
+  LSTD_ASSERT(hash_set != NULL);
+  return HashTable_has(hash_set, set_value);
+}
+size_t HashSet_length(const HashSet *hash_set) {
+  LSTD_ASSERT(hash_set != NULL);
+  return HashTable_length(hash_set);
+}
+void HashSet_clear(HashSet *hash_set) {
+  LSTD_ASSERT(hash_set != NULL);
+  HashTable_clear(hash_set);
+}
+
+struct HashTableIt {
+  HashTable *table;
+  size_t current_index;
+  bool iterating;
+};
+
+HashTableIt *HashTableIt_create(Allocator *allocator, HashTable *table) {
+  LSTD_ASSERT(allocator != NULL);
+  LSTD_ASSERT(table != NULL);
+  HashTableIt *it = Allocator_allocate(allocator, sizeof(HashTableIt));
+  it->table = table;
+  it->current_index = 0;
+  it->iterating = false;
+  return it;
+}
+
+void HashTableIt_destroy(Allocator *allocator, HashTableIt *it) {
+  LSTD_ASSERT(allocator != NULL);
+  LSTD_ASSERT(it != NULL);
+  Allocator_free(allocator, it);
+}
+
+bool HashTableIt_next(HashTableIt *it) {
+  LSTD_ASSERT(it != NULL);
+  if (it->table->length < 1) {
+    return false;
+  }
+
+  if (it->iterating) {
+    it->current_index++;
+  } else {
+    it->iterating = true;
+  }
+
+  if (it->current_index >= it->table->capacity) {
+    return false;
+  }
+
+  while (!it->table->items[it->current_index].is_present) {
+    it->current_index++;
+    if (it->current_index >= it->table->capacity) {
+      return false;
+    }
+  }
+
+  return true;
+}
+void *HashTableIt_key(HashTableIt *it) {
+  LSTD_ASSERT(it != NULL);
+  if (!it->iterating || it->current_index >= it->table->capacity)
+    return NULL;
+
+  if (!it->table->items[it->current_index].is_present) {
+    return NULL;
+  }
+
+  return it->table->items[it->current_index].key;
+}
+void *HashTableIt_value(HashTableIt *it) {
+  LSTD_ASSERT(it != NULL);
+  if (!it->iterating || it->current_index >= it->table->capacity)
+    return NULL;
+
+  if (!it->table->items[it->current_index].is_present) {
+    return NULL;
+  }
+
+  return it->table->items[it->current_index].value;
+}
+
+HashTableIt *HashTable_iter(Allocator *allocator, HashTable *hash_table) {
+  LSTD_ASSERT(hash_table != NULL);
+  return HashTableIt_create(allocator, hash_table);
+}
+
+uint64_t hash_fnv_1a(const char *bytes, size_t nbytes) {
+  LSTD_ASSERT(bytes != NULL);
+  static const uint64_t FNV_OFFSET_BASIS = 14695981039346656037u;
+  static const uint64_t FNV_PRIME = 1099511628211u;
+  uint64_t hash = FNV_OFFSET_BASIS;
+  for (size_t i = 0; i < nbytes; i++) {
+    hash = hash ^ bytes[i];
+    hash = hash * FNV_PRIME;
+  }
+
+  return hash;
+}
+
+uint64_t hash_str_hash(const void *str) {
+  LSTD_ASSERT(str != NULL);
+  return hash_fnv_1a(str, strlen(str));
+}
+
+bool hash_str_eq(const void *a, const void *b) {
+  LSTD_ASSERT(a != NULL);
+  LSTD_ASSERT(b != NULL);
+  return strcmp(a, b) == 0;
+}
+void hash_str_dctor(Allocator *allocator, void *str) {
+  LSTD_ASSERT(allocator != NULL);
+  LSTD_ASSERT(str != NULL);
+  Allocator_free(allocator, str);
+}
diff --git a/src/lisiblestd/hash.h b/src/lisiblestd/hash.h
new file mode 100644
index 0000000..0c9190c
--- /dev/null
+++ b/src/lisiblestd/hash.h
@@ -0,0 +1,72 @@
+#ifndef LSTD_HASH_H
+#define LSTD_HASH_H
+
+#include "memory.h"
+#include <stdbool.h>
+
+typedef struct {
+  void *key;
+  void *value;
+  bool is_present;
+} HashTableKV;
+
+typedef uint64_t (*HashTableKeyHashFn)(const void *);
+typedef void (*HashTableDctorFn)(Allocator *, void *);
+typedef bool (*HashTableKeyEqFn)(const void *, const void *);
+typedef struct {
+  Allocator *allocator;
+  HashTableKV *items;
+  HashTableKeyHashFn key_hash_fn;
+  HashTableKeyEqFn key_eq_fn;
+  HashTableDctorFn key_dctor_fn;
+  HashTableDctorFn value_dctor_fn;
+  size_t capacity;
+  size_t length;
+} HashTable;
+
+typedef struct HashTableIt HashTableIt;
+void HashTableIt_destroy(Allocator *allocator, HashTableIt *it);
+bool HashTableIt_next(HashTableIt *it);
+void *HashTableIt_key(HashTableIt *it);
+void *HashTableIt_value(HashTableIt *it);
+
+bool HashTable_init(Allocator *allocator, HashTable *hash_table,
+                    const size_t initial_capacity,
+                    HashTableKeyHashFn key_hash_fn, HashTableKeyEqFn key_eq_fn);
+bool HashTable_init_with_dctors(Allocator *allocator, HashTable *hash_table,
+                                const size_t initial_capacity,
+                                HashTableKeyHashFn key_hash_fn,
+                                HashTableKeyEqFn key_eq_fn,
+                                HashTableDctorFn key_dctor_fn,
+                                HashTableDctorFn value_dctor_fn);
+void HashTable_deinit(HashTable *hash_table);
+bool HashTable_insert(HashTable *hash_table, void *key, void *value);
+HashTableIt *HashTable_iter(Allocator *allocator, HashTable *hash_table);
+void *HashTable_get(const HashTable *hash_table, const void *key);
+bool HashTable_has(const HashTable *hash_table, const void *key);
+size_t HashTable_length(const HashTable *hash_table);
+void HashTable_steal(HashTable *hash_table, const void *key);
+void HashTable_clear(HashTable *hash_table);
+
+typedef HashTable HashSet;
+
+bool HashSet_init(Allocator *allocator, HashSet *hash_set,
+                  const size_t initial_capacity, HashTableKeyHashFn hash_fn,
+                  HashTableKeyEqFn eq_fn);
+bool HashSet_init_with_dctor(Allocator *allocator, HashSet *hash_set,
+                             const size_t initial_capacity,
+                             HashTableKeyHashFn hash_fn, HashTableKeyEqFn eq_fn,
+                             HashTableDctorFn dctor_fn);
+void HashSet_deinit(HashSet *hash_set);
+bool HashSet_insert(HashSet *hash_set, void *set_value);
+bool HashSet_has(const HashSet *hash_set, const void *set_value);
+size_t HashSet_length(const HashSet *hash_set);
+void HashSet_clear(HashSet *hash_set);
+
+void HashTable_noop_dctor_fn(Allocator *, void *v);
+
+uint64_t hash_str_hash(const void *str);
+bool hash_str_eq(const void *a, const void *b);
+void hash_str_dctor(Allocator *allocator, void *str);
+
+#endif // LSTD_HASH_H
-- 
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