dcfg/include/dcfg.h

/*
 * Copyright 2025 Slendi <slendi@socopon.com>
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this software and associated documentation files (the “Software”), to deal
 * in the Software without restriction, including without limitation the rights
 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
 * copies of the Software, and to permit persons to whom the Software is
 * furnished to do so, subject to the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED “AS IS”, WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 */

#ifndef DCFG_H
#define DCFG_H

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

#ifdef __cplusplus
extern "C" {
#endif

typedef struct dcfg_Value dcfg_Value;
typedef struct dcfg_Instance dcfg_Instance;

// Type definitions
typedef struct dcfg_StringView {
	char const *data;
	size_t size;
} dcfg_StringView;
#define dcfg_SV(cstr) ((dcfg_StringView) { .data = cstr, .size = strlen(cstr) })

typedef void *(*dcfg_AllocFn)(size_t); // This should automatically zero memory.
typedef void (*dcfg_FreeFn)(void *);
typedef char *(*dcfg_RealpathFn)(char const *);
typedef void *(*dcfg_FopenFn)(char const *, char const *);
typedef int (*dcfg_FseekFn)(void *, size_t, int);
typedef long (*dcfg_FtellFn)(void *);

typedef struct dcfg_InstanceCreateInfo {
	// Default using libc
	dcfg_AllocFn alloc;
	dcfg_FreeFn free;

	// If POSIX support is enabled, all of those are defined if NULL.
	dcfg_RealpathFn realpath;
	dcfg_FopenFn fopen;
	dcfg_FseekFn fseek;
	dcfg_FtellFn ftell;
} dcfg_InstanceCreateInfo;

typedef enum dcfg_ValueKind {
	dcfg_ValueType_Nil,
	dcfg_ValueType_Boolean,
	dcfg_ValueType_Integer,
	dcfg_ValueType_Real,
	dcfg_ValueType_String,
	dcfg_ValueType_Path,
	dcfg_ValueType_Object,
	dcfg_ValueType_Array,
	dcfg_ValueType_Function,
	dcfg_ValueType_MemberAccess,
	dcfg_ValueType_FunctionCall,
} dcfg_ValueType;

typedef dcfg_Value *(*dcfg_BuiltIn)(dcfg_Value **argv, size_t argc);

typedef uint64_t dcfg_Version;
#define DCFG_GET_MAJOR(v) (((v) >> 48) & 0xFFFF)
#define DCFG_GET_MINOR(v) (((v) >> 32) & 0xFFFF)
#define DCFG_GET_PATCH(v) ((v) & 0xFFFFFFFF)

dcfg_Version dcfg_get_version(void);

dcfg_Instance *dcfg_make_instance(dcfg_InstanceCreateInfo const *create_info);
void dcfg_destroy_instance(dcfg_Instance *instance);

char const *dcfg_last_error(dcfg_Instance *instance);

// File path gets copied internally to instance to a Value * -> path hashmap for
// evaluation.
dcfg_Value *dcfg_parse(
    dcfg_Instance *instance, dcfg_StringView const file_path);
void dcfg_destroy(dcfg_Value *value);

bool dcfg_serialize_value(dcfg_Value *value, dcfg_StringView *out_sv);

// Value type checking
dcfg_ValueType dcfg_Value_type_ex(dcfg_Value *value, bool evaluate);
static inline dcfg_ValueType dcfg_Value_type(dcfg_Value *value)
{
	return dcfg_Value_type_ex(value, true);
}

// Value getters
bool dcfg_Value_get_object_field_ex(dcfg_Value *value,
    dcfg_StringView const key, dcfg_Value **out_value, bool const evaluate);
bool dcfg_Value_get_array_item_ex(dcfg_Value *value, size_t const index,
    dcfg_Value **out_value, bool const evaluate);
bool dcfg_Value_get_function_body_ex(
    dcfg_Value *value, dcfg_Value **out_value, bool evaluate);

bool dcfg_Value_get_boolean(dcfg_Value *value, bool *out_value);
bool dcfg_Value_get_integer(dcfg_Value *value, int64_t *out_value);
bool dcfg_Value_get_real(dcfg_Value *value, double *out_value);
bool dcfg_Value_get_string(dcfg_Value *value, dcfg_StringView *out_sv);
bool dcfg_Value_get_path(dcfg_Value *value, dcfg_StringView *out_sv);
bool dcfg_Value_get_object_keys(dcfg_Value *value, size_t const capacity,
    size_t *out_count, dcfg_StringView *out_keys);
bool dcfg_Value_get_array_size(dcfg_Value *value, size_t *out_size);

static inline bool dcfg_Value_get_object_field(
    dcfg_Value *value, dcfg_StringView const key, dcfg_Value **out_value)
{
	return dcfg_Value_get_object_field_ex(value, key, out_value, true);
}
static inline bool dcfg_Value_get_array_item(
    dcfg_Value *value, size_t const index, dcfg_Value **out_value)
{
	return dcfg_Value_get_array_item_ex(value, index, out_value, true);
}
static inline bool dcfg_Value_get_function_body(
    dcfg_Value *value, dcfg_Value **out_value)
{
	return dcfg_Value_get_function_body_ex(value, out_value, true);
}

// Allocates new values
bool dcfg_call_function(dcfg_Value *function, dcfg_Value **args,
    size_t arg_count, dcfg_Value **out_value);
// Allocates new values
bool dcfg_Value_evaluate(dcfg_Value *value, dcfg_Value **out_value);
// Allocates new values
bool dcfg_Value_evaluate_toplevel(dcfg_Value *top, dcfg_Value **out_value,
    dcfg_StringView *function_names, dcfg_BuiltIn *functions,
    size_t function_count);

#ifdef __cplusplus
}
#endif

#endif // DCFG_H