gp_data_storage.h

// SPDX-License-Identifier: LGPL-2.1-or-later
/*
 * Copyright (C) 2009-2014 Cyril Hrubis <metan@ucw.cz>
 */
 
/*
 
   Data storage is an abstraction for recusive, typed, name -> value pairs.
 
   It's designed to be common layer for metadata such as exif, etc.
 
 */
 
#ifndef LOADERS_DATA_STORAGE_H
#define LOADERS_DATA_STORAGE_H
 
enum gp_data_type {
        GP_DATA_INT,
        GP_DATA_STRING,
        GP_DATA_DOUBLE,
        GP_DATA_RATIONAL,
        GP_DATA_DICT,
};
 
struct gp_data_rational {
        long num;
        long den;
};
 
typedef struct gp_storage gp_storage;
typedef struct gp_data_dict gp_data_dict;
 
union gp_data_value {
        long i;
        double d;
        const char *str;
        struct gp_data_rational rat;
        gp_data_dict *dict;
};
 
typedef struct gp_data_node {
        enum gp_data_type type;
        union gp_data_value value;
        const char *id;
        struct gp_data_node *next;
} gp_data_node;
 
/*
 * Creates a data storage
 */
gp_storage *gp_storage_create(void);
 
/*
 * Destroys a data storage and all its data
 */
void gp_storage_destroy(gp_storage *self);
 
/*
 * Returns storage root node.
 */
gp_data_node *gp_storage_root(gp_storage *self);
 
/*
 * Returns first node in a dict node list.
 */
gp_data_node *gp_data_dict_first(gp_data_node *node);
 
/*
 * Clears all data in storage.
 */
void gp_storage_clear(gp_storage *self);
 
/*
 * Prints a data
 */
void gp_data_print(const gp_data_node *node);
 
static inline void gp_storage_print(gp_storage *self)
{
        gp_data_print(gp_storage_root(self));
}
 
const char *gp_data_type_name(enum gp_data_type type);
 
/*
 * Returns subnode of a given id (or NULL) starting at node.
 *
 * If node is NULL storage root is used.
 */
gp_data_node *gp_storage_get(gp_storage *self,
                             gp_data_node *node, const char *id);
 
/*
 * Returns data node by a path in the data storage.
 *
 * Example path: "/Exif/Orientation"
 *
 * The path works like filesystem path. The equivalent to working
 * directory is the node pointer.
 */
gp_data_node *gp_storage_get_by_path(gp_storage *self, gp_data_node *node,
                                     const char *path);
 
/*
 * Adds data into a dict.
 *
 * If node is NULL, data storage root is used.
 *
 * The data holds information to be used for the node addition.
 *
 * Returns newly created node or NULL in case of failure.
 */
gp_data_node *gp_storage_add(gp_storage *self,
                             gp_data_node *node, gp_data_node *data);
 
/*
 * Shortcuts for adding a int/string/double/rational
 *
 * If dict is NULL data is added to the root.
 */
gp_data_node *gp_storage_add_int(gp_storage *self, gp_data_node *node,
                                 const char *id, long i);
 
gp_data_node *gp_storage_add_string(gp_storage *self, gp_data_node *node,
                                    const char *id, const char *str);
 
gp_data_node *gp_storage_add_double(gp_storage *self, gp_data_node *node,
                                    const char *id, double d);
 
gp_data_node *gp_storage_add_rational(gp_storage *self, gp_data_node *node,
                                      const char *id, long num, long den);
 
gp_data_node *gp_storage_add_dict(gp_storage *self, gp_data_node *node,
                                  const char *id);
 
#endif /* LOADERS_GP_DATA_STORAGE_H */