#pragma once

/**
 * \file
 */

#ifdef __cplusplus
extern "C" {
#endif

#include <stddef.h>
#include <stdlib.h>

/*!
 * Defines how a cMix Buffer allocater should look like.
 */
typedef char*(*CmixBufferAllocator)(size_t);
/*!
 * Defines how a cMix Buffer deallocater should look like.
 */
typedef void(*CmixBufferDeallocator)(void*);
/*!
 * Defines how the function looks like that returns the length of one message in this buffer implementation.
 */
typedef size_t(*CmixBufferMessageLength)();

/*!
 * \brief The CmixBufferImpl struct
 */
struct CmixBufferImpl {
	CmixBufferAllocator allocate_cmix_buffer; ///< pointer to function to implementation specific allocater.
	CmixBufferDeallocator deallocate_cmix_buffer; ///< pointer to function to implementation specific deallocater.
	CmixBufferMessageLength message_length; ///< pointer to function to implementation specific function returning message length.
};

/*!
 * \def DEFINE_CIPHER(NAME, MESSAGE_SIZE)
 * Generates some cipher specific boilerplate for manipulating the message buffer.
 */

#define DEFINE_CIPHER(NAME, MESSAGE_SIZE)\
typedef char NAME ## Message[MESSAGE_SIZE];\
\
char* allocate_ ## NAME ## _cmix_buffer(size_t size){\
	return (char*) calloc(size, sizeof(NAME ## Message));\
}\
\
void deallocate_ ## NAME ## _cmix_buffer(void* buffer) {\
	free(buffer);\
}\
\
size_t NAME ## _message_length() {\
	return sizeof(NAME ## Message);\
}\
\
struct CmixBufferImpl get_cmix_ ## NAME ## _buffer_implementation() {\
	return (struct CmixBufferImpl) {\
		allocate_ ## NAME ## _cmix_buffer,\
		deallocate_ ## NAME ## _cmix_buffer,\
		NAME ## _message_length\
	};\
}

/*!
 * #DEFINE_CIPHER(Null, 0)
 */
DEFINE_CIPHER(Null, 0)

/*!
 * #DEFINE_CIPHER(Curve25519, 31)
 */
DEFINE_CIPHER(Curve25519, 31)

#undef DEFINE_CIPHER

#ifdef __cplusplus
} // extern "C"
#endif