Files
scylladb/net/byteorder.hh
2015-01-12 14:11:56 +02:00

107 lines
2.5 KiB
C++

/*
* Copyright (C) 2014 Cloudius Systems, Ltd.
*/
#ifndef BYTEORDER_HH_
#define BYTEORDER_HH_
#include <arpa/inet.h> // for ntohs() and friends
#include <iosfwd>
#include <utility>
inline uint64_t ntohq(uint64_t v) {
return __builtin_bswap64(v);
}
inline uint64_t htonq(uint64_t v) {
return __builtin_bswap64(v);
}
namespace net {
inline void ntoh() {}
inline void hton() {}
inline uint16_t ntoh(uint16_t x) { return ntohs(x); }
inline uint16_t hton(uint16_t x) { return htons(x); }
inline uint32_t ntoh(uint32_t x) { return ntohl(x); }
inline uint32_t hton(uint32_t x) { return htonl(x); }
inline uint64_t ntoh(uint64_t x) { return ntohq(x); }
inline uint64_t hton(uint64_t x) { return htonq(x); }
// Wrapper around a primitive type to provide an unaligned version.
// This is because gcc (correctly) doesn't allow binding an unaligned
// scalar variable to a reference, and (unfortunately) doesn't allow
// specifying unaligned references.
//
// So, packed<uint32_t>& is our way of passing a reference (or pointer)
// to a uint32_t around, without losing the knowledge about its alignment
// or lack thereof.
template <typename T>
struct packed {
T raw;
packed() = default;
packed(T x) : raw(x) {}
packed& operator=(const T& x) { raw = x; return *this; }
operator T() const { return raw; }
template <typename Adjuster>
void adjust_endianness(Adjuster a) { a(raw); }
} __attribute__((packed));
template <typename T>
inline T ntoh(const packed<T>& x) {
T v = x;
return ntoh(v);
}
template <typename T>
inline T hton(const packed<T>& x) {
T v = x;
return hton(v);
}
template <typename T>
inline std::ostream& operator<<(std::ostream& os, const packed<T>& v) {
auto x = v.raw;
return os << x;
}
inline
void ntoh_inplace() {}
inline
void hton_inplace() {};
template <typename First, typename... Rest>
inline
void ntoh_inplace(First& first, Rest&... rest) {
first = ntoh(first);
ntoh_inplace(std::forward<Rest&>(rest)...);
}
template <typename First, typename... Rest>
inline
void hton_inplace(First& first, Rest&... rest) {
first = hton(first);
hton_inplace(std::forward<Rest&>(rest)...);
}
template <class T>
inline
T ntoh(const T& x) {
T tmp = x;
tmp.adjust_endianness([] (auto&&... what) { ntoh_inplace(std::forward<decltype(what)&>(what)...); });
return tmp;
}
template <class T>
inline
T hton(const T& x) {
T tmp = x;
tmp.adjust_endianness([] (auto&&... what) { hton_inplace(std::forward<decltype(what)&>(what)...); });
return tmp;
}
}
#endif /* BYTEORDER_HH_ */