/* libmisc/endian.c - Endian-conversion helpers
 *
 * Copyright (C) 2024-2025  Luke T. Shumaker <lukeshu@lukeshu.com>
 * SPDX-License-Identifier: AGPL-3.0-or-later
 */

#include <libmisc/macro.h> /* for LM_FORCE_SEMICOLON */

#include <libmisc/endian.h>

#define endian_declare_wrappers(NBIT, ENDIAN)                                      \
	uint##NBIT##ENDIAN##_t uint##NBIT##ENDIAN##_marshal(uint##NBIT##_t in) {   \
		uint##NBIT##ENDIAN##_t out;                                        \
		uint##NBIT##ENDIAN##_encode(out.octets, in);                       \
		return out;                                                        \
	}                                                                          \
	uint##NBIT##_t uint##NBIT##ENDIAN##_unmarshal(uint##NBIT##ENDIAN##_t in) { \
		return uint##NBIT##ENDIAN##_decode(in.octets);                     \
	}                                                                          \
	LM_FORCE_SEMICOLON

/* Big endian *****************************************************************/

size_t uint16be_encode(uint8_t *out, uint16_t in) {
	out[0] = (uint8_t)((in >> 8) & 0xFF);
	out[1] = (uint8_t)((in >> 0) & 0xFF);
	return 2;
}

uint16_t uint16be_decode(uint8_t *in) {
	return (((uint16_t)(in[0])) << 8)
	     | (((uint16_t)(in[1])) << 0)
	     ;
}

size_t uint32be_encode(uint8_t *out, uint32_t in) {
	out[0] = (uint8_t)((in >> 24) & 0xFF);
	out[1] = (uint8_t)((in >> 16) & 0xFF);
	out[2] = (uint8_t)((in >>  8) & 0xFF);
	out[3] = (uint8_t)((in >>  0) & 0xFF);
	return 4;
}

uint32_t uint32be_decode(uint8_t *in) {
	return (((uint32_t)(in[0])) << 24)
	     | (((uint32_t)(in[1])) << 16)
	     | (((uint32_t)(in[2])) <<  8)
	     | (((uint32_t)(in[3])) <<  0)
	     ;
}

size_t uint64be_encode(uint8_t *out, uint64_t in) {
	out[0] = (uint8_t)((in >> 56) & 0xFF);
	out[1] = (uint8_t)((in >> 48) & 0xFF);
	out[2] = (uint8_t)((in >> 40) & 0xFF);
	out[3] = (uint8_t)((in >> 32) & 0xFF);
	out[4] = (uint8_t)((in >> 24) & 0xFF);
	out[5] = (uint8_t)((in >> 16) & 0xFF);
	out[6] = (uint8_t)((in >>  8) & 0xFF);
	out[7] = (uint8_t)((in >>  0) & 0xFF);
	return 8;
}

uint64_t uint64be_decode(uint8_t *in) {
	return (((uint64_t)(in[0])) << 56)
	     | (((uint64_t)(in[1])) << 48)
	     | (((uint64_t)(in[2])) << 40)
	     | (((uint64_t)(in[3])) << 32)
	     | (((uint64_t)(in[4])) << 24)
	     | (((uint64_t)(in[5])) << 16)
	     | (((uint64_t)(in[6])) <<  8)
	     | (((uint64_t)(in[7])) <<  0)
	     ;
}

endian_declare_wrappers(16, be);
endian_declare_wrappers(32, be);
endian_declare_wrappers(64, be);

/* Little endian **************************************************************/

size_t uint16le_encode(uint8_t *out, uint16_t in) {
	out[0] = (uint8_t)((in >> 0) & 0xFF);
	out[1] = (uint8_t)((in >> 8) & 0xFF);
	return 2;
}

uint16_t uint16le_decode(uint8_t *in) {
	return (((uint16_t)(in[0])) << 0)
	     | (((uint16_t)(in[1])) << 8)
	     ;
}

size_t uint32le_encode(uint8_t *out, uint32_t in) {
	out[0] = (uint8_t)((in >>  0) & 0xFF);
	out[1] = (uint8_t)((in >>  8) & 0xFF);
	out[2] = (uint8_t)((in >> 16) & 0xFF);
	out[3] = (uint8_t)((in >> 24) & 0xFF);
	return 4;
}

uint32_t uint32le_decode(uint8_t *in) {
	return (((uint32_t)(in[0])) <<  0)
	     | (((uint32_t)(in[1])) <<  8)
	     | (((uint32_t)(in[2])) << 16)
	     | (((uint32_t)(in[3])) << 24)
	     ;
}

size_t uint64le_encode(uint8_t *out, uint64_t in) {
	out[0] = (uint8_t)((in >>  0) & 0xFF);
	out[1] = (uint8_t)((in >>  8) & 0xFF);
	out[2] = (uint8_t)((in >> 16) & 0xFF);
	out[3] = (uint8_t)((in >> 24) & 0xFF);
	out[4] = (uint8_t)((in >> 32) & 0xFF);
	out[5] = (uint8_t)((in >> 40) & 0xFF);
	out[6] = (uint8_t)((in >> 48) & 0xFF);
	out[7] = (uint8_t)((in >> 56) & 0xFF);
	return 8;
}

uint64_t uint64le_decode(uint8_t *in) {
	return (((uint64_t)(in[0])) <<  0)
	     | (((uint64_t)(in[1])) <<  8)
	     | (((uint64_t)(in[2])) << 16)
	     | (((uint64_t)(in[3])) << 24)
	     | (((uint64_t)(in[4])) << 32)
	     | (((uint64_t)(in[5])) << 40)
	     | (((uint64_t)(in[6])) << 48)
	     | (((uint64_t)(in[7])) << 56)
	     ;
}

endian_declare_wrappers(16, le);
endian_declare_wrappers(32, le);
endian_declare_wrappers(64, le);