uxplayer/lib/byteutils.c
2025-05-03 17:09:23 +08:00

128 lines
3.7 KiB
C

/*
* Copyright (c) 2019 dsafa22, All Rights Reserved.
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation; either
* version 2.1 of the License, or (at your option) any later version.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
*=================================================================
* modified by fduncanh 2021-23
*/
#define SECOND_IN_NSECS 1000000000UL
#include <time.h>
#ifdef _WIN32
# include <winsock2.h>
#else
# include <netinet/in.h>
#endif
#include "byteutils.h"
#ifdef _WIN32
# ifndef ntonll
# define ntohll(x) ((1==ntohl(1)) ? (x) : (((uint64_t)ntohl((x) & 0xFFFFFFFFUL)) << 32) | ntohl((uint32_t)((x) >> 32)))
# endif
#else
# ifndef htonll
# ifdef SYS_ENDIAN_H
# include <sys/endian.h>
# else
# include <endian.h>
# endif
# define htonll(x) htobe64(x)
# define ntohll(x) be64toh(x)
# endif
#endif
// The functions in this file assume a little endian cpu architecture!
/**
* Reads a little endian unsigned 16 bit integer from the buffer at position offset
*/
uint16_t byteutils_get_short(unsigned char* b, int offset) {
return *((uint16_t*)(b + offset));
}
/**
* Reads a little endian unsigned 32 bit integer from the buffer at position offset
*/
uint32_t byteutils_get_int(unsigned char* b, int offset) {
return *((uint32_t*)(b + offset));
}
/**
* Reads a little endian unsigned 64 bit integer from the buffer at position offset
*/
uint64_t byteutils_get_long(unsigned char* b, int offset) {
return *((uint64_t*)(b + offset));
}
/**
* Reads a big endian unsigned 16 bit integer from the buffer at position offset
*/
uint16_t byteutils_get_short_be(unsigned char* b, int offset) {
return ntohs(byteutils_get_short(b, offset));
}
/**
* Reads a big endian unsigned 32 bit integer from the buffer at position offset
*/
uint32_t byteutils_get_int_be(unsigned char* b, int offset) {
return ntohl(byteutils_get_int(b, offset));
}
/**
* Reads a big endian unsigned 64 bit integer from the buffer at position offset
*/
uint64_t byteutils_get_long_be(unsigned char* b, int offset) {
return ntohll(byteutils_get_long(b, offset));
}
/**
* Reads a float from the buffer at position offset
*/
float byteutils_get_float(unsigned char* b, int offset) {
return *((float*)(b + offset));
}
/**
* Writes a little endian unsigned 32 bit integer to the buffer at position offset
*/
void byteutils_put_int(unsigned char* b, int offset, uint32_t value) {
*((uint32_t*)(b + offset)) = value;
}
/**
* Reads an ntp timestamp and returns it as nano seconds since the Unix epoch
*/
uint64_t byteutils_get_ntp_timestamp(unsigned char *b, int offset) {
uint64_t seconds = ntohl(((unsigned int) byteutils_get_int(b, offset))) - SECONDS_FROM_1900_TO_1970;
uint64_t fraction = ntohl((unsigned int) byteutils_get_int(b, offset + 4));
return (seconds * SECOND_IN_NSECS) + ((fraction * SECOND_IN_NSECS) >> 32);
}
/**
* Writes a time given as nano seconds since the Unix time epoch as an ntp timestamp
* into the buffer at position offset
*/
void byteutils_put_ntp_timestamp(unsigned char *b, int offset, uint64_t ns_since_1970) {
uint64_t seconds = ns_since_1970 / SECOND_IN_NSECS;
uint64_t nanoseconds = ns_since_1970 % SECOND_IN_NSECS;
seconds += SECONDS_FROM_1900_TO_1970;
uint64_t fraction = (nanoseconds << 32) / SECOND_IN_NSECS;
// Write in big endian!
byteutils_put_int(b, offset, htonl(seconds));
byteutils_put_int(b, offset + 4, htonl(fraction));
}