ini-config/src/ini-config.h

#ifndef INI_CONFIG_H
#define INI_CONFIG_H

#include <stdlib.h>
#include <string.h>
#include <stdint.h>
#include <stdbool.h>

#ifdef __cplusplus
extern "C" {
#endif

/**
 * Struct for transformer functions used for properly loading and saving the config item's value.
 */
typedef struct {
	/**
	 * Function that formats the value from memory to a value that is write-friendly to the config file.
	 */
	void* serialize;
	/**
	 * Function that formats the value from file to a value that is read-friendly to memory.
	 */
	void* deserialize;
} INI_ConfigTransformer; // TODO: should we unify this with INI_ConfigType?

struct INI_ConfigItem;

/**
 * Function for loading a config item value from file to memory.
 */
typedef void INI_ConfigTypeLoad(struct INI_ConfigItem*, const char*, void*);

/**
 * Result enum for saving config items.
 */
typedef enum {
	/**
	 * Result returned when saving a config item was not successful.
	 */
	INI_CONFIG_SAVE_ITEM_ERROR = -1,

	/**
	 * Result returned when saving a config item was successful.
	 */
	INI_CONFIG_SAVE_ITEM_OK,
} INI_ConfigSaveItemResult;

/**
 * Function for saving a config item value from memory to file.
 */
typedef INI_ConfigSaveItemResult INI_ConfigTypeSave(struct INI_ConfigItem*, const char*, void*);

/**
 * Function for retrieving a config item value from the command-line to memory.
 */
typedef void INI_ConfigTypeOverride(struct INI_ConfigItem*, uint8_t, const char* []);

/**
 * Struct for the config item type.
 */
typedef struct {
	/**
	 * Size of the corresponding in-memory value of the config item.
	 */
	size_t size;
	/**
	 * Load function.
	 * @see INI_ConfigTypeLoad
	 */
	INI_ConfigTypeLoad* load;
	/**
	 * Save function.
	 * @see INI_ConfigTypeSave
	 */
	INI_ConfigTypeSave* save;
	/**
	 * Override function.
	 * @see INI_ConfigTypeOverride
	 */
	INI_ConfigTypeOverride* override;
} INI_ConfigType;

/**
 * Struct for the config item, which occuptes a single key in a specific section of the config INI file.
 */
typedef struct INI_ConfigItem {
	/**
	 * Type of the config item.
	 */
	INI_ConfigType type;
	/**
	 * Section where this config item can be found.
	 */
	const char* section;
	/**
	 * Key where this config item value is serialized and stored.
	 */
	const char* key;
	/**
	 * Command-line option for overriding this config item's value.
	 */
	const char* cmdline_option; // TODO: should we extract commandline parsing logic?
	/**
	 * Default value of the config item, when the value could not be read from the config file.
	 */
	const void* default_value;
	/**
	 * Validator function for the config item's value.
	 */
	void* validator;
	/**
	 * Transformer functions.
	 * @see INI_ConfigTransformer
	 */
	INI_ConfigTransformer transformer;
	/**
	 * The memory address where the config item value will reside. This property should allow storing the amount of butes
	 * specified under `type.size`.
	 */
	void* dest;
} INI_ConfigItem;

/**
 * Retrieves the value from a command-line option.
 * @return The string value from the command-line option.
 */
const char* INI_ConfigGetCommandlineOption(uint8_t, const char*[], const char*);

/**
 * Result enum for initializing config items.
 */
typedef enum {
	/**
	 * Result returned when initializing all config items was not successful.
	 */
	INI_CONFIG_INITIALIZE_RESULT_ERROR = -1,
	/**
	 * Result returned when initializing all config items was successful.
	 */
	INI_CONFIG_INITIALIZE_RESULT_OK,
	/**
	 * Result returned when initializing some config items was successful.
	 */
	INI_CONFIG_INITIALIZE_RESULT_WARNING
} INI_ConfigInitializeResult;

/**
 * Syncs the config file to memory. This includes the loading of the items from the config file.
 * @return Result of the initialization.
 */
INI_ConfigInitializeResult INI_ConfigInitialize(INI_ConfigItem[], const char*, uint8_t, const char*[]);

typedef int32_t INI_ConfigSaveResult;

/**
 * Saves the contents of the memory to the config file.
 * @return
 */
INI_ConfigSaveResult INI_ConfigSave(INI_ConfigItem[], const char*);

#ifdef __cplusplus
};
#endif

#define INI_CONFIG_DECLARE_TYPE(ID) \
INI_ConfigTypeLoad INI_ConfigLoad##ID; \
INI_ConfigTypeSave INI_ConfigSave##ID; \
INI_ConfigTypeOverride INI_ConfigOverride##ID

/**
 * Null transformer.
 */
#define INI_CONFIG_TRANSFORMER_NONE (INI_ConfigTransformer) { \
  .serialize = NULL, \
  .deserialize = NULL, \
}

/**
 * Null item. Use this to signify the end of the config item list.
 */
#define INI_CONFIG_ITEM_NULL (INI_ConfigItem) { \
  (INI_ConfigType) { \
    .size = 0, \
    .load = NULL, \
    .save = NULL, \
    .override = NULL, \
  }, \
  NULL, \
  NULL, \
  NULL, \
  NULL, \
  NULL, \
  INI_CONFIG_TRANSFORMER_NONE, \
  NULL, \
}

#endif