tree.h

#ifndef SIMPLE_DB_C_TREE_H
#define SIMPLE_DB_C_TREE_H

#include "consts.h"
#include "stdio.h"
#include "stdlib.h"

// same value with ROW_SIZE in db.c
const uint32_t ROW_SIZ = 293;

// Common Node Header Layout
const uint32_t NODE_TYPE_SIZE = sizeof(uint8_t);
const uint32_t NODE_TYPE_OFFSET = 0;
const uint32_t IS_ROOT_SIZE = sizeof(uint8_t);
const uint32_t IS_ROOT_OFFSET = NODE_TYPE_SIZE;
const uint32_t PARENT_POINTER_SIZE = sizeof(uint32_t);
const uint32_t PARENT_POINTER_OFFSET = IS_ROOT_OFFSET + IS_ROOT_SIZE;
const uint8_t COMMON_NODE_HEADER_SIZE =
    NODE_TYPE_SIZE + IS_ROOT_SIZE + PARENT_POINTER_SIZE;

// Leaf Node Header Layout
const uint32_t LEAF_NODE_NUM_CELLS_SIZE = sizeof(uint32_t);
const uint32_t LEAF_NODE_NUM_CELLS_OFFSET = COMMON_NODE_HEADER_SIZE;
const uint32_t LEAF_NODE_HEADER_SIZE =
    COMMON_NODE_HEADER_SIZE + LEAF_NODE_NUM_CELLS_SIZE;

// Leaf Node Body Layout
const uint32_t LEAF_NODE_KEY_SIZE = sizeof(uint32_t);
const uint32_t LEAF_NODE_KEY_OFFSET = 0;
const uint32_t LEAF_NODE_VALUE_SIZE = ROW_SIZ;
const uint32_t LEAF_NODE_VALUE_OFFSET =
    LEAF_NODE_KEY_OFFSET + LEAF_NODE_KEY_OFFSET;
const uint32_t LEAF_NODE_CELL_SIZE = LEAF_NODE_KEY_SIZE + LEAF_NODE_VALUE_SIZE;
const uint32_t LEAF_NODE_SPACE_FOR_CELLS = PAGE_SIZE - LEAF_NODE_HEADER_SIZE;
const uint32_t LEAF_NODE_MAX_CELLS =
    LEAF_NODE_SPACE_FOR_CELLS / LEAF_NODE_CELL_SIZE;

typedef enum {
  NODE_INTERNAL,
  NODE_LEAF,
} NodeType;

uint32_t* leaf_node_num_cells(void* node) {
  return node + LEAF_NODE_NUM_CELLS_OFFSET;
}

void* leaf_node_cell(void* node, uint32_t cell_num) {
  return node + LEAF_NODE_HEADER_SIZE + cell_num * LEAF_NODE_CELL_SIZE;
}

uint32_t* leaf_node_key(void* node, uint32_t cell_num) {
  return leaf_node_cell(node, cell_num);
}

void* leaf_node_value(void* node, uint32_t cell_num) {
  return leaf_node_cell(node, cell_num) + LEAF_NODE_KEY_SIZE;
}

void initialize_leaaf_node(void* node) { *leaf_node_num_cells(node) = 0; }

void print_constants() {
  printf("ROW_SIZE: %d\n", ROW_SIZ);
  printf("COMMON_NODE_HEADER_SIZE: %d\n", COMMON_NODE_HEADER_SIZE);
  printf("LEAF_NODE_HEADER_SIZE: %d\n", LEAF_NODE_HEADER_SIZE);
  printf("LEAF_NODE_CELL_SIZE: %d\n", LEAF_NODE_CELL_SIZE);
  printf("LEAF_NODE_SPACE_FOR_CELLS: %d\n", LEAF_NODE_SPACE_FOR_CELLS);
  printf("LEAF_NODE_MAX_CELLS: %d\n", LEAF_NODE_MAX_CELLS);
}

void print_leaf_node(void* node) {
  uint32_t num_cells = *leaf_node_num_cells(node);
  printf("leaf (size %d)\n", num_cells);
  for (uint32_t i = 0; i < num_cells; i++) {
    uint32_t key = *leaf_node_key(node, i);
    printf("   - %d : %d\n", i, key);
  }
}

#endif  // SIMPLE_DB_C_TREE_H