config.h

#ifndef CONFIG_H
#define CONFIG_H

#include <stdbool.h>
#include <stdint.h>
#include <stdio.h>

#define CFG_FILE_EXT ".cfg"

#define CFG_MAX_KEY 32
#define CFG_MAX_VAL 64
#define CFG_MAX_ERR 64

typedef struct {
    int off;
    int col;
    int row;
    char msg[CFG_MAX_ERR];
} CfgError;

typedef struct {
    uint8_t r;
    uint8_t g;
    uint8_t b;
    uint8_t a;
} CfgColor;

typedef enum {
    CFG_TYPE_STRING,
    CFG_TYPE_BOOL,
    CFG_TYPE_INT,
    CFG_TYPE_FLOAT,
    CFG_TYPE_COLOR,
} CfgValType;

typedef union {
    char string[CFG_MAX_VAL + 1];
    bool boolean;
    int integer;
    float floating;
    CfgColor color;
} CfgVal;

typedef struct {
    CfgValType type;
    char key[CFG_MAX_KEY + 1];
    CfgVal val;
} CfgEntry;

typedef struct {
    CfgEntry *entries;
    int count;
    int capacity;
} Cfg;

/**
 * @brief Parses the source data and populates the Cfg object
 *
 * @param[in] src The source data
 * @param[in] src_len Length of the source data
 * @param[in,out] cfg The Cfg object to be populated
 * @param[out] err Buffer to store error messages
 *
 * @return 0 if parsing is successful, -1 otherwise
 */
int cfg_parse(const char *src, int src_len, Cfg *cfg, CfgError *err);

/**
 * @brief Loads and parses a config file
 *
 * @param[in] filename Path of the config file
 * @param[in,out] cfg The Cfg object to be populated
 * @param[out] err Buffer to store error messages
 *
 * @return 0 if loading and parsing are successful, -1 otherwise
 *
 * @see cfg_parse() The underlying "wrapped" function
 */
int cfg_parse_file(const char *filename, Cfg *cfg, CfgError *err);

char *cfg_get_string(Cfg *cfg, const char *key, char *fallback);
bool cfg_get_bool(Cfg *cfg, const char *key, bool fallback);
int cfg_get_int(Cfg *cfg, const char *key, int fallback);
float cfg_get_float(Cfg *cfg, const char *key, float fallback);
CfgColor cfg_get_color(Cfg *cfg, const char *key, CfgColor fallback);

int cfg_get_int_min(Cfg *cfg, const char *key, int fallback, int min);
int cfg_get_int_max(Cfg *cfg, const char *key, int fallback, int max);
int cfg_get_int_range(Cfg *cfg,
                      const char *key,
                      int fallback,
                      int min,
                      int max);

float cfg_get_float_min(Cfg *cfg, const char *key, float fallback, float min);
float cfg_get_float_max(Cfg *cfg, const char *key, float fallback, float max);
float cfg_get_float_range(Cfg *cfg,
                          const char *key,
                          float fallback,
                          float min,
                          float max);

void cfg_fprint(FILE *stream, Cfg *cfg);
void cfg_fprint_error(FILE *stream, CfgError *err);

#endif