begin kvtable

.gitignore

@@ -0,0 +1 @@
+bin/*

inc/kv.h

@@ -0,0 +1,22 @@
+#ifndef KV_H
+#define KV_H
+
+#include <stdlib.h>
+
+typedef struct
+{
+  char *key;
+  char *val;
+} kv_entry_t;
+
+typedef struct
+{
+  size_t capacity;
+  size_t count;
+  kv_entry_t *entries;
+} kv_t;
+
+kv_t *kv_init(size_t capacity);
+int kv_put(kv_t *db, char *key, char *val);
+
+#endif

src/kv.c

@@ -0,0 +1,88 @@
+#include <kv.h>
+#include <string.h>
+#include <stdlib.h>
+
+#define TOMBSTONE 0x1
+
+size_t hash(char *val, int capacity)
+{
+  size_t hash = 0x13371337deadbeef;
+
+  while (*val)
+  {
+    hash ^= *val;
+    hash = hash << 8;
+    hash += *val;
+
+    val++;
+  }
+
+  return hash % capacity;
+}
+
+// fn kv_put
+// params:
+//  - db: a pointer to the db
+//  - key: pointer to the key value
+//  - val: pointer to the value
+// returns: index of the key, or -1 on error, -2 on not found
+int kv_put(kv_t *db, char *key, char *val)
+{
+  if (!db || !key || !val) return -1;
+
+  size_t index = hash(key, db->capacity);
+
+  for (int i = 0; i < db->capacity - 1; ++i)
+  {
+    size_t idx = (index + i) % db->capacity;
+    kv_entry_t *e = &db->entries[idx];
+
+    if (e->key &&
+        e->key != (void*)TOMBSTONE &&
+        !strcmp(e->key, key))
+    {
+      char *newval = strdup(val);
+      if (!newval) return -1;
+      e->val = newval;
+      return idx;
+    }
+
+    if (!e->key || e->key == (void*)TOMBSTONE)
+    {
+      char *newkey = strdup(key);
+      char *newval = strdup(val);
+      if (!newval || !newkey)
+      {
+        free(newkey);
+        free(newval);
+        return -1;
+      }
+      e->key = newkey;
+      e->val = newval;
+      db->count++;
+      return idx;
+    }
+  }
+
+  return -2;
+}
+
+kv_t *kv_init(size_t capacity)
+{
+  if (capacity == 0) return NULL;
+
+  kv_t *table = malloc(sizeof(kv_t));
+  if (table == NULL) return NULL;
+
+  table->capacity = capacity;
+  table->count = 0;
+
+  table->entries = calloc(sizeof(kv_entry_t), capacity);
+  if (table->entries == NULL)
+  {
+    free(table);
+    return NULL;
+  }
+
+  return table;
+}

src/main.c

@@ -0,0 +1,21 @@
+#include <stdio.h>
+#include <kv.h>
+
+int main(void)
+{
+  kv_t *table = kv_init(1024);
+  printf("%p\n", table);
+  printf("%ld\n", table->capacity);
+
+  kv_put(table, "hello", "world");
+  kv_put(table, "hello", "people");
+  kv_put(table, "goodbye", "world");
+
+  for (int i = 0; i < table->capacity; ++i)
+  {
+    if (table->entries[i].key)
+    {
+      printf("[%d] %s: %s\n", i, table->entries[i].key, table->entries[i].val);
+    }
+  }
+}