constants.h

#pragma once
#include <errno.h>
#include <fcntl.h>
#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <unistd.h>


typedef enum
{
  NODE_INTERNAL,
  NODE_LEAF
} NodeType;



typedef struct
{
  char *buffer;
  size_t buffer_length;
  ssize_t input_length;
} InputBuffer;

typedef enum
{
  EXECUTE_SUCCESS,
  EXECUTE_DUPLICATE_KEY,
} ExecuteResult;

typedef enum
{
  META_COMMAND_SUCCESS,
  META_COMMAND_UNRECOGNIZED_COMMAND
} MetaCommandResult;

typedef enum
{
  PREPARE_SUCCESS,
  PREPARE_NEGATIVE_ID,
  PREPARE_STRING_TOO_LONG,
  PREPARE_SYNTAX_ERROR,
  PREPARE_UNRECOGNIZED_STATEMENT
} PrepareResult;

typedef enum
{
  STATEMENT_INSERT,
  STATEMENT_SELECT
} StatementType;

#define COLUMN_USERNAME_SIZE 32
#define COLUMN_EMAIL_SIZE 255
typedef struct
{
  uint32_t id;
  char username[COLUMN_USERNAME_SIZE + 1];
  char email[COLUMN_EMAIL_SIZE + 1];
} Row;

typedef struct
{
  uint32_t id;
  std::string username;
  std::string email;
} Select_Row;

typedef struct
{
  StatementType type;
  Row row_to_insert; // only used by insert statement
  Row row_to_select; // only used by select statement
  std::map<std::string,bool> attributes_to_select;
} Statement;

#define size_of_attribute(Struct, Attribute) sizeof(((Struct *)0)->Attribute)

const uint32_t ID_SIZE = size_of_attribute(Row, id);
const uint32_t USERNAME_SIZE = size_of_attribute(Row, username);
const uint32_t EMAIL_SIZE = size_of_attribute(Row, email);
const uint32_t ID_OFFSET = 0;
const uint32_t USERNAME_OFFSET = ID_OFFSET + ID_SIZE;
const uint32_t EMAIL_OFFSET = USERNAME_OFFSET + USERNAME_SIZE;
const uint32_t ROW_SIZE = ID_SIZE + USERNAME_SIZE + EMAIL_SIZE;

const uint32_t PAGE_SIZE = 4096;
#define TABLE_MAX_PAGES 400

#define INVALID_PAGE_NUM UINT32_MAX

typedef struct
{
  int file_descriptor;
  uint32_t file_length;
  uint32_t num_pages;
  void *pages[TABLE_MAX_PAGES];
} Pager;

typedef struct
{
  Pager *pager;
  uint32_t root_page_num;
} Table;

typedef struct
{
  Table *table;
  uint32_t page_num;
  uint32_t cell_num;
  bool end_of_table; // Indicates a position one past the last element
} Cursor;

/*
 * 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;

/*
 * Internal Node Header Layout
 */
const uint32_t INTERNAL_NODE_NUM_KEYS_SIZE = sizeof(uint32_t);
const uint32_t INTERNAL_NODE_NUM_KEYS_OFFSET = COMMON_NODE_HEADER_SIZE;
const uint32_t INTERNAL_NODE_RIGHT_CHILD_SIZE = sizeof(uint32_t);
const uint32_t INTERNAL_NODE_RIGHT_CHILD_OFFSET =
    INTERNAL_NODE_NUM_KEYS_OFFSET + INTERNAL_NODE_NUM_KEYS_SIZE;
const uint32_t INTERNAL_NODE_HEADER_SIZE = COMMON_NODE_HEADER_SIZE +
                                           INTERNAL_NODE_NUM_KEYS_SIZE +
                                           INTERNAL_NODE_RIGHT_CHILD_SIZE;

/*
 * Internal Node Body Layout
 */
const uint32_t INTERNAL_NODE_KEY_SIZE = sizeof(uint32_t);
const uint32_t INTERNAL_NODE_CHILD_SIZE = sizeof(uint32_t);
const uint32_t INTERNAL_NODE_CELL_SIZE =
    INTERNAL_NODE_CHILD_SIZE + INTERNAL_NODE_KEY_SIZE;
/* Keep this small for testing */
const uint32_t INTERNAL_NODE_MAX_KEYS = 3;

/*
 * 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_NEXT_LEAF_SIZE = sizeof(uint32_t);
const uint32_t LEAF_NODE_NEXT_LEAF_OFFSET =
    LEAF_NODE_NUM_CELLS_OFFSET + LEAF_NODE_NUM_CELLS_SIZE;
const uint32_t LEAF_NODE_HEADER_SIZE = COMMON_NODE_HEADER_SIZE +
                                       LEAF_NODE_NUM_CELLS_SIZE +
                                       LEAF_NODE_NEXT_LEAF_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_SIZE;
const uint32_t LEAF_NODE_VALUE_OFFSET =
    LEAF_NODE_KEY_OFFSET + LEAF_NODE_KEY_SIZE;
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;
const uint32_t LEAF_NODE_RIGHT_SPLIT_COUNT = (LEAF_NODE_MAX_CELLS + 1) / 2;
const uint32_t LEAF_NODE_LEFT_SPLIT_COUNT =
    (LEAF_NODE_MAX_CELLS + 1) - LEAF_NODE_RIGHT_SPLIT_COUNT;