db_structs.h

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#pragma once
#include <stdio.h>
 
typedef size_t Page;
 
#define YACDB_FILE_NAME "yac.db"
#define YACDB_SIGNATURE "YACDB format"
#define YACDB_PAGE_SIZE 512
#define YACDB_DEFAULT_CACHE_SIZE 10
 
struct yacdb_header
{
    char signature[13];
    unsigned short page_size;
 
    unsigned int change_counter;
 
    Page nb_pages;
    unsigned int default_cache_size;
 
    Page nb_free_pages;
    Page fst_free_page;
};
 
struct yacdb
{
    FILE *file;
    struct yacdb_header *header;
 
    struct cached_node *cache;
    size_t cache_size;
 
    // Page *cache;
    // int cache_size;
    // int cache_index;
    // int cache_count;
};
 
enum page_type
{
    NODE_TYPE_TABLE_LEAF = 13,
    NODE_TYPE_TABLE_INTERIOR = 5,
    NODE_TYPE_INDEX_LEAF = 10,
    NODE_TYPE_INDEX_INTERIOR = 2
};
 
struct btree_header
{
    Page parent_addr;
    enum page_type page_type;
    unsigned short nb_cells;
    Page right_pointer;
};
 
struct overflow_header
{
    Page next_page;
    size_t size;
};
 
struct overflow_data
{
    size_t size;
    void *data;
};
 
struct ti_cell
{
    unsigned int key;
    Page pointer;
};
 
struct tl_cell_header
{
    unsigned int key;
    unsigned int size;
    Page overflow;
};
 
struct tl_cell
{
    struct tl_cell_header *header;
    void *data;
};
 
struct btree_page
{
    struct yacdb *yacdb;
    struct btree_header *btree_h;
 
    void **cells_h;
 
    Page page;
 
    void *data;
 
    unsigned short *offsets;
};