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compiler.hh
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compiler.hh
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/* Masstree
* Eddie Kohler, Yandong Mao, Robert Morris
* Copyright (c) 2012-2014 President and Fellows of Harvard College
* Copyright (c) 2012-2014 Massachusetts Institute of Technology
*
* 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, subject to the conditions
* listed in the Masstree LICENSE file. These conditions include: you must
* preserve this copyright notice, and you cannot mention the copyright
* holders in advertising related to the Software without their permission.
* The Software is provided WITHOUT ANY WARRANTY, EXPRESS OR IMPLIED. This
* notice is a summary of the Masstree LICENSE file; the license in that file
* is legally binding.
*/
#ifndef MASSTREE_COMPILER_HH
#define MASSTREE_COMPILER_HH 1
#include <stdint.h>
#define __STDC_FORMAT_MACROS
#include <inttypes.h>
#include <arpa/inet.h>
#if HAVE_TYPE_TRAITS
#include <type_traits>
#endif
#define arraysize(a) (sizeof(a) / sizeof((a)[0]))
#define likely(x) __builtin_expect(!!(x), 1)
#define unlikely(x) __builtin_expect(!!(x), 0)
#if !HAVE_CXX_STATIC_ASSERT
#define static_assert(x, msg) switch (x) case 0: case !!(x):
#endif
#if !HAVE_CXX_CONSTEXPR
#define constexpr const
#endif
#if HAVE_OFF_T_IS_LONG_LONG
#define PRIdOFF_T "lld"
#else
#define PRIdOFF_T "ld"
#endif
#if HAVE_SIZE_T_IS_UNSIGNED_LONG_LONG
#define PRIdSIZE_T "llu"
#define PRIdSSIZE_T "lld"
#elif HAVE_SIZE_T_IS_UNSIGNED_LONG
#define PRIdSIZE_T "lu"
#define PRIdSSIZE_T "ld"
#else
#define PRIdSIZE_T "u"
#define PRIdSSIZE_T "d"
#endif
#if (__i386__ || __x86_64__) && !defined(__x86__)
# define __x86__ 1
#endif
#define PREFER_X86 1
#define ALLOW___SYNC_BUILTINS 1
#if !defined(HAVE_INDIFFERENT_ALIGMENT) && (__i386__ || __x86_64__ || __arch_um__)
# define HAVE_INDIFFERENT_ALIGNMENT 1
#endif
/** @brief Return the index of the most significant bit set in @a x.
* @return 0 if @a x = 0; otherwise the index of first bit set, where the
* most significant bit is numbered 1.
*/
inline int ffs_msb(unsigned x) {
return (x ? __builtin_clz(x) + 1 : 0);
}
/** @overload */
inline int ffs_msb(unsigned long x) {
return (x ? __builtin_clzl(x) + 1 : 0);
}
/** @overload */
inline int ffs_msb(unsigned long long x) {
return (x ? __builtin_clzll(x) + 1 : 0);
}
/** @brief Compiler fence.
*
* Prevents reordering of loads and stores by the compiler. Not intended to
* synchronize the processor's caches. */
inline void fence() {
asm volatile("" : : : "memory");
}
/** @brief Acquire fence. */
inline void acquire_fence() {
asm volatile("" : : : "memory");
}
/** @brief Release fence. */
inline void release_fence() {
asm volatile("" : : : "memory");
}
/** @brief Compiler fence that relaxes the processor.
Use this in spinloops, for example. */
inline void relax_fence() {
asm volatile("pause" : : : "memory"); // equivalent to "rep; nop"
}
/** @brief Full memory fence. */
inline void memory_fence() {
asm volatile("mfence" : : : "memory");
}
/** @brief Do-nothing function object. */
struct do_nothing {
void operator()() const {
}
template <typename T>
void operator()(const T&) const {
}
template <typename T, typename U>
void operator()(const T&, const U&) const {
}
};
/** @brief Function object that calls fence(). */
struct fence_function {
void operator()() const {
fence();
}
};
/** @brief Function object that calls relax_fence(). */
struct relax_fence_function {
void operator()() const {
relax_fence();
}
};
/** @brief Function object that calls relax_fence() with backoff. */
struct backoff_fence_function {
backoff_fence_function()
: count_(0) {
}
void operator()() {
for (int i = count_; i >= 0; --i)
relax_fence();
count_ = ((count_ << 1) | 1) & 15;
}
private:
int count_;
};
template <int SIZE, typename BARRIER> struct sized_compiler_operations;
template <typename B> struct sized_compiler_operations<1, B> {
typedef char type;
static inline type xchg(type* object, type new_value) {
asm volatile("xchgb %0,%1"
: "+q" (new_value), "+m" (*object));
B()();
return new_value;
}
static inline type val_cmpxchg(type* object, type expected, type desired) {
#if __x86__ && (PREFER_X86 || !HAVE___SYNC_VAL_COMPARE_AND_SWAP)
asm volatile("lock; cmpxchgb %2,%1"
: "+a" (expected), "+m" (*object)
: "r" (desired) : "cc");
B()();
return expected;
#else
return __sync_val_compare_and_swap(object, expected, desired);
#endif
}
static inline bool bool_cmpxchg(type* object, type expected, type desired) {
#if HAVE___SYNC_BOOL_COMPARE_AND_SWAP && ALLOW___SYNC_BUILTINS
return __sync_bool_compare_and_swap(object, expected, desired);
#else
bool result;
asm volatile("lock; cmpxchgb %3,%1; sete %b2"
: "+a" (expected), "+m" (*object), "=q" (result)
: "q" (desired) : "cc");
B()();
return result;
#endif
}
static inline type fetch_and_add(type *object, type addend) {
#if __x86__ && (PREFER_X86 || !HAVE___SYNC_FETCH_AND_ADD)
asm volatile("lock; xaddb %0,%1"
: "+q" (addend), "+m" (*object) : : "cc");
B()();
return addend;
#else
return __sync_fetch_and_add(object, addend);
#endif
}
static inline void atomic_or(type* object, type addend) {
#if __x86__
asm volatile("lock; orb %0,%1"
: "=r" (addend), "+m" (*object) : : "cc");
B()();
#else
__sync_fetch_and_or(object, addend);
#endif
}
};
template <typename B> struct sized_compiler_operations<2, B> {
#if SIZEOF_SHORT == 2
typedef short type;
#else
typedef int16_t type;
#endif
static inline type xchg(type* object, type new_value) {
asm volatile("xchgw %0,%1"
: "+r" (new_value), "+m" (*object));
B()();
return new_value;
}
static inline type val_cmpxchg(type* object, type expected, type desired) {
#if __x86__ && (PREFER_X86 || !HAVE___SYNC_VAL_COMPARE_AND_SWAP)
asm volatile("lock; cmpxchgw %2,%1"
: "+a" (expected), "+m" (*object)
: "r" (desired) : "cc");
B()();
return expected;
#else
return __sync_val_compare_and_swap(object, expected, desired);
#endif
}
static inline bool bool_cmpxchg(type* object, type expected, type desired) {
#if HAVE___SYNC_BOOL_COMPARE_AND_SWAP && ALLOW___SYNC_BUILTINS
return __sync_bool_compare_and_swap(object, expected, desired);
#else
bool result;
asm volatile("lock; cmpxchgw %3,%1; sete %b2"
: "+a" (expected), "+m" (*object), "=q" (result)
: "r" (desired) : "cc");
B()();
return result;
#endif
}
static inline type fetch_and_add(type* object, type addend) {
#if __x86__ && (PREFER_X86 || !HAVE___SYNC_FETCH_AND_ADD)
asm volatile("lock; xaddw %0,%1"
: "+r" (addend), "+m" (*object) : : "cc");
B()();
return addend;
#else
return __sync_fetch_and_add(object, addend);
#endif
}
static inline void atomic_or(type* object, type addend) {
#if __x86__
asm volatile("lock; orw %0,%1"
: "=r" (addend), "+m" (*object) : : "cc");
B()();
#else
__sync_fetch_and_or(object, addend);
#endif
}
};
template <typename B> struct sized_compiler_operations<4, B> {
#if SIZEOF_INT == 4
typedef int type;
#else
typedef int32_t type;
#endif
static inline type xchg(type* object, type new_value) {
asm volatile("xchgl %0,%1"
: "+r" (new_value), "+m" (*object));
B()();
return new_value;
}
static inline type val_cmpxchg(type* object, type expected, type desired) {
#if __x86__ && (PREFER_X86 || !HAVE___SYNC_VAL_COMPARE_AND_SWAP)
asm volatile("lock; cmpxchgl %2,%1"
: "+a" (expected), "+m" (*object)
: "r" (desired) : "cc");
B()();
return expected;
#else
return __sync_val_compare_and_swap(object, expected, desired);
#endif
}
static inline bool bool_cmpxchg(type* object, type expected, type desired) {
#if HAVE___SYNC_BOOL_COMPARE_AND_SWAP && ALLOW___SYNC_BUILTINS
return __sync_bool_compare_and_swap(object, expected, desired);
#else
bool result;
asm volatile("lock; cmpxchgl %3,%1; sete %b2"
: "+a" (expected), "+m" (*object), "=q" (result)
: "r" (desired) : "cc");
B()();
return result;
#endif
}
static inline type fetch_and_add(type *object, type addend) {
#if __x86__ && (PREFER_X86 || !HAVE___SYNC_FETCH_AND_ADD)
asm volatile("lock; xaddl %0,%1"
: "+r" (addend), "+m" (*object) : : "cc");
B()();
return addend;
#else
return __sync_fetch_and_add(object, addend);
#endif
}
static inline void atomic_or(type* object, type addend) {
#if __x86__
asm volatile("lock; orl %0,%1"
: "=r" (addend), "+m" (*object) : : "cc");
B()();
#else
__sync_fetch_and_or(object, addend);
#endif
}
};
template <typename B> struct sized_compiler_operations<8, B> {
#if SIZEOF_LONG_LONG == 8
typedef long long type;
#elif SIZEOF_LONG == 8
typedef long type;
#else
typedef int64_t type;
#endif
#if __x86_64__
static inline type xchg(type* object, type new_value) {
asm volatile("xchgq %0,%1"
: "+r" (new_value), "+m" (*object));
B()();
return new_value;
}
#endif
static inline type val_cmpxchg(type* object, type expected, type desired) {
#if __x86_64__ && (PREFER_X86 || !HAVE___SYNC_VAL_COMPARE_AND_SWAP_8)
asm volatile("lock; cmpxchgq %2,%1"
: "+a" (expected), "+m" (*object)
: "r" (desired) : "cc");
B()();
return expected;
#elif __i386__ && (PREFER_X86 || !HAVE___SYNC_VAL_COMPARE_AND_SWAP_8)
uint32_t expected_low(expected), expected_high(expected >> 32),
desired_low(desired), desired_high(desired >> 32);
asm volatile("lock; cmpxchg8b %2"
: "+a" (expected_low), "+d" (expected_high), "+m" (*object)
: "b" (desired_low), "c" (desired_high) : "cc");
B()();
return ((uint64_t) expected_high << 32) | expected_low;
#elif HAVE___SYNC_VAL_COMPARE_AND_SWAP_8
return __sync_val_compare_and_swap(object, expected, desired);
#endif
}
static inline bool bool_cmpxchg(type* object, type expected, type desired) {
#if HAVE___SYNC_BOOL_COMPARE_AND_SWAP_8 && ALLOW___SYNC_BUILTINS
return __sync_bool_compare_and_swap(object, expected, desired);
#elif __x86_64__
bool result;
asm volatile("lock; cmpxchgq %3,%1; sete %b2"
: "+a" (expected), "+m" (*object), "=q" (result)
: "r" (desired) : "cc");
B()();
return result;
#else
uint32_t expected_low(expected), expected_high(expected >> 32),
desired_low(desired), desired_high(desired >> 32);
bool result;
asm volatile("lock; cmpxchg8b %2; sete %b4"
: "+a" (expected_low), "+d" (expected_high),
"+m" (*object), "=q" (result)
: "b" (desired_low), "c" (desired_high) : "cc");
B()();
return result;
#endif
}
#if __x86_64__ || HAVE___SYNC_FETCH_AND_ADD_8
static inline type fetch_and_add(type* object, type addend) {
# if __x86_64__ && (PREFER_X86 || !HAVE___SYNC_FETCH_AND_ADD_8)
asm volatile("lock; xaddq %0,%1"
: "+r" (addend), "+m" (*object) : : "cc");
B()();
return addend;
# else
return __sync_fetch_and_add(object, addend);
# endif
}
#endif
#if __x86_64__ || HAVE___SYNC_FETCH_AND_OR_8
static inline void atomic_or(type* object, type addend) {
#if __x86_64__
asm volatile("lock; orq %0,%1"
: "=r" (addend), "+m" (*object) : : "cc");
B()();
#else
__sync_fetch_and_or(object, addend);
#endif
}
#endif
};
template<typename T>
inline T xchg(T* object, T new_value) {
typedef sized_compiler_operations<sizeof(T), fence_function> sco_t;
typedef typename sco_t::type type;
return (T) sco_t::xchg((type*) object, (type) new_value);
}
inline int8_t xchg(int8_t* object, int new_value) {
return xchg(object, (int8_t) new_value);
}
inline uint8_t xchg(uint8_t* object, int new_value) {
return xchg(object, (uint8_t) new_value);
}
inline int16_t xchg(int16_t* object, int new_value) {
return xchg(object, (int16_t) new_value);
}
inline uint16_t xchg(uint16_t* object, int new_value) {
return xchg(object, (uint16_t) new_value);
}
inline unsigned xchg(unsigned* object, int new_value) {
return xchg(object, (unsigned) new_value);
}
/** @brief Atomic compare and exchange. Return actual old value.
* @param object pointer to memory value
* @param expected old value
* @param desired new value
* @return actual old value
*
* Acts like an atomic version of:
* @code
* T actual(*object);
* if (actual == expected)
* *object = desired;
* return actual;
* @endcode */
template <typename T>
inline T cmpxchg(T* object, T expected, T desired) {
typedef sized_compiler_operations<sizeof(T), fence_function> sco_t;
typedef typename sco_t::type type;
return (T) sco_t::val_cmpxchg((type*) object, (type) expected, (type) desired);
}
inline unsigned cmpxchg(unsigned *object, int expected, int desired) {
return cmpxchg(object, unsigned(expected), unsigned(desired));
}
/** @brief Atomic compare and exchange. Return true iff swap succeeds.
* @param object pointer to memory value
* @param expected old value
* @param desired new value
* @return true if swap succeeded, false otherwise
*
* Acts like an atomic version of:
* @code
* T actual(*object);
* if (actual == expected) {
* *object = desired;
* return true;
* } else
* return false;
* @endcode */
template <typename T>
inline bool bool_cmpxchg(T* object, T expected, T desired) {
typedef sized_compiler_operations<sizeof(T), fence_function> sco_t;
typedef typename sco_t::type type;
return sco_t::bool_cmpxchg((type*) object, (type) expected, (type) desired);
}
inline bool bool_cmpxchg(uint8_t* object, int expected, int desired) {
return bool_cmpxchg(object, uint8_t(expected), uint8_t(desired));
}
inline bool bool_cmpxchg(unsigned *object, int expected, int desired) {
return bool_cmpxchg(object, unsigned(expected), unsigned(desired));
}
/** @brief Atomic fetch-and-add. Return the old value.
* @param object pointer to integer
* @param addend value to add
* @return old value */
template <typename T>
inline T fetch_and_add(T* object, T addend) {
typedef sized_compiler_operations<sizeof(T), fence_function> sco_t;
typedef typename sco_t::type type;
return (T) sco_t::fetch_and_add((type*) object, (type) addend);
}
template <typename T>
inline T* fetch_and_add(T** object, int addend) {
typedef sized_compiler_operations<sizeof(T*), fence_function> sco_t;
typedef typename sco_t::type type;
return (T*) sco_t::fetch_and_add((type*) object, (type) (addend * sizeof(T)));
}
inline int8_t fetch_and_add(int8_t* object, int addend) {
return fetch_and_add(object, int8_t(addend));
}
inline uint8_t fetch_and_add(uint8_t* object, int addend) {
return fetch_and_add(object, uint8_t(addend));
}
inline int16_t fetch_and_add(int16_t* object, int addend) {
return fetch_and_add(object, int16_t(addend));
}
inline uint16_t fetch_and_add(uint16_t* object, int addend) {
return fetch_and_add(object, uint16_t(addend));
}
inline unsigned fetch_and_add(unsigned* object, int addend) {
return fetch_and_add(object, unsigned(addend));
}
inline unsigned long fetch_and_add(unsigned long* object, int addend) {
return fetch_and_add(object, (unsigned long)(addend));
}
/** @brief Test-and-set lock acquire. */
template <typename T>
inline void test_and_set_acquire(T* object) {
typedef sized_compiler_operations<sizeof(T), do_nothing> sco_t;
typedef typename sco_t::type type;
while (sco_t::xchg((type*) object, (type) 1))
relax_fence();
acquire_fence();
}
/** @brief Test-and-set lock release. */
template <typename T>
inline void test_and_set_release(T* object) {
release_fence();
*object = T();
}
/** @brief Atomic fetch-and-or. Returns nothing.
* @param object pointer to integer
* @param addend value to or */
template <typename T>
inline void atomic_or(T* object, T addend) {
typedef sized_compiler_operations<sizeof(T), fence_function> sco_t;
typedef typename sco_t::type type;
sco_t::atomic_or((type*) object, (type) addend);
}
inline void atomic_or(int8_t* object, int addend) {
atomic_or(object, int8_t(addend));
}
inline void atomic_or(uint8_t* object, int addend) {
atomic_or(object, uint8_t(addend));
}
inline void atomic_or(int16_t* object, int addend) {
atomic_or(object, int16_t(addend));
}
inline void atomic_or(uint16_t* object, int addend) {
atomic_or(object, uint16_t(addend));
}
inline void atomic_or(unsigned* object, int addend) {
atomic_or(object, unsigned(addend));
}
inline void atomic_or(unsigned long* object, int addend) {
atomic_or(object, (unsigned long)(addend));
}
// prefetch instruction
#if !PREFETCH_DEFINED
inline void prefetch(const void *ptr) {
#ifdef NOPREFETCH
(void) ptr;
#else
typedef struct { char x[CACHE_LINE_SIZE]; } cacheline_t;
asm volatile("prefetcht0 %0" : : "m" (*(const cacheline_t *)ptr));
#endif
}
#endif
inline void prefetchnta(const void *ptr) {
#ifdef NOPREFETCH
(void) ptr;
#else
typedef struct { char x[CACHE_LINE_SIZE]; } cacheline_t;
asm volatile("prefetchnta %0" : : "m" (*(const cacheline_t *)ptr));
#endif
}
template <typename T>
struct value_prefetcher {
void operator()(T) {
}
};
template <typename T>
struct value_prefetcher<T *> {
void operator()(T *p) {
prefetch((const void *) p);
}
};
// stolen from Linux
inline uint64_t ntohq(uint64_t val) {
#ifdef __i386__
union {
struct {
uint32_t a;
uint32_t b;
} s;
uint64_t u;
} v;
v.u = val;
asm("bswapl %0; bswapl %1; xchgl %0,%1"
: "+r" (v.s.a), "+r" (v.s.b));
return v.u;
#else /* __i386__ */
asm("bswapq %0" : "+r" (val));
return val;
#endif
}
inline uint64_t htonq(uint64_t val) {
return ntohq(val);
}
/** Bit counting. */
/** @brief Return the number of leading 0 bits in @a x.
* @pre @a x != 0
*
* "Leading" means "most significant." */
#if HAVE___BUILTIN_CLZ
inline int clz(int x) {
return __builtin_clz(x);
}
inline int clz(unsigned x) {
return __builtin_clz(x);
}
#endif
#if HAVE___BUILTIN_CLZL
inline int clz(long x) {
return __builtin_clzl(x);
}
inline int clz(unsigned long x) {
return __builtin_clzl(x);
}
#endif
#if HAVE___BUILTIN_CLZLL
inline int clz(long long x) {
return __builtin_clzll(x);
}
inline int clz(unsigned long long x) {
return __builtin_clzll(x);
}
#endif
/** @brief Return the number of trailing 0 bits in @a x.
* @pre @a x != 0
*
* "Trailing" means "least significant." */
#if HAVE___BUILTIN_CTZ
inline int ctz(int x) {
return __builtin_ctz(x);
}
inline int ctz(unsigned x) {
return __builtin_ctz(x);
}
#endif
#if HAVE___BUILTIN_CTZL
inline int ctz(long x) {
return __builtin_ctzl(x);
}
inline int ctz(unsigned long x) {
return __builtin_ctzl(x);
}
#endif
#if HAVE___BUILTIN_CTZLL
inline int ctz(long long x) {
return __builtin_ctzll(x);
}
inline int ctz(unsigned long long x) {
return __builtin_ctzll(x);
}
#endif
template <typename T, typename U>
inline T iceil(T x, U y) {
U mod = x % y;
return x + (mod ? y - mod : 0);
}
/** @brief Return the smallest power of 2 greater than or equal to @a x.
@pre @a x != 0
@pre the result is representable in type T (that is, @a x can't be
larger than the largest power of 2 representable in type T) */
template <typename T>
inline T iceil_log2(T x) {
return T(1) << (sizeof(T) * 8 - clz(x) - !(x & (x - 1)));
}
/** @brief Return the largest power of 2 less than or equal to @a x.
@pre @a x != 0 */
template <typename T>
inline T ifloor_log2(T x) {
return T(1) << (sizeof(T) * 8 - 1 - clz(x));
}
/** @brief Return the index of the lowest 0 nibble in @a x.
*
* 0 is the lowest-order nibble. Returns -1 if no nibbles are 0. */
template <typename T>
inline int find_lowest_zero_nibble(T x) {
static_assert(sizeof(T) <= sizeof(unsigned long long), "T is too big");
#if SIZEOF_LONG_LONG == 16
T h = T(0x88888888888888888888888888888888ULL), l = T(0x11111111111111111111111111111111ULL);
#else
T h = T(0x8888888888888888ULL), l = T(0x1111111111111111ULL);
#endif
T t = h & (x - l) & ~x;
return t ? ctz(t) >> 2 : -1;
}
/** @brief Translate @a x to network byte order.
*
* Compare htons/htonl/htonq. host_to_net_order is particularly useful in
* template functions, where the type to be translated to network byte order
* is unknown. */
inline unsigned char host_to_net_order(unsigned char x) {
return x;
}
/** @overload */
inline signed char host_to_net_order(signed char x) {
return x;
}
/** @overload */
inline char host_to_net_order(char x) {
return x;
}
/** @overload */
inline short host_to_net_order(short x) {
return htons(x);
}
/** @overload */
inline unsigned short host_to_net_order(unsigned short x) {
return htons(x);
}
/** @overload */
inline int host_to_net_order(int x) {
return htonl(x);
}
/** @overload */
inline unsigned host_to_net_order(unsigned x) {
return htonl(x);
}
#if SIZEOF_LONG == 4
/** @overload */
inline long host_to_net_order(long x) {
return htonl(x);
}
/** @overload */
inline unsigned long host_to_net_order(unsigned long x) {
return htonl(x);
}
#elif SIZEOF_LONG == 8
/** @overload */
inline long host_to_net_order(long x) {
return htonq(x);
}
/** @overload */
inline unsigned long host_to_net_order(unsigned long x) {
return htonq(x);
}
#endif
#if SIZEOF_LONG_LONG == 8
/** @overload */
inline long long host_to_net_order(long long x) {
return htonq(x);
}
/** @overload */
inline unsigned long long host_to_net_order(unsigned long long x) {
return htonq(x);
}
#endif
#if !HAVE_INT64_T_IS_LONG && !HAVE_INT64_T_IS_LONG_LONG
/** @overload */
inline int64_t host_to_net_order(int64_t x) {
return htonq(x);
}
/** @overload */
inline uint64_t host_to_net_order(uint64_t x) {
return htonq(x);
}
#endif
/** @overload */
inline double host_to_net_order(float x) {
union { float f; uint32_t i; } v;
v.f = x;
v.i = host_to_net_order(v.i);
return v.f;
}
/** @overload */
inline double host_to_net_order(double x) {
union { double d; uint64_t i; } v;
v.d = x;
v.i = host_to_net_order(v.i);
return v.d;
}
/** @brief Translate @a x to host byte order.
*
* Compare ntohs/ntohl/ntohq. net_to_host_order is particularly useful in
* template functions, where the type to be translated to network byte order
* is unknown. */
inline unsigned char net_to_host_order(unsigned char x) {
return x;
}
/** @overload */
inline signed char net_to_host_order(signed char x) {
return x;
}
/** @overload */
inline char net_to_host_order(char x) {
return x;
}
/** @overload */
inline short net_to_host_order(short x) {
return ntohs(x);
}
/** @overload */
inline unsigned short net_to_host_order(unsigned short x) {
return ntohs(x);
}
/** @overload */
inline int net_to_host_order(int x) {
return ntohl(x);
}
/** @overload */
inline unsigned net_to_host_order(unsigned x) {
return ntohl(x);
}
#if SIZEOF_LONG == 4
/** @overload */
inline long net_to_host_order(long x) {
return ntohl(x);
}
/** @overload */
inline unsigned long net_to_host_order(unsigned long x) {
return ntohl(x);
}
#elif SIZEOF_LONG == 8
/** @overload */
inline long net_to_host_order(long x) {
return ntohq(x);
}
/** @overload */
inline unsigned long net_to_host_order(unsigned long x) {
return ntohq(x);
}
#endif
#if SIZEOF_LONG_LONG == 8
/** @overload */
inline long long net_to_host_order(long long x) {
return ntohq(x);
}
/** @overload */
inline unsigned long long net_to_host_order(unsigned long long x) {
return ntohq(x);
}
#endif
#if !HAVE_INT64_T_IS_LONG && !HAVE_INT64_T_IS_LONG_LONG
/** @overload */
inline int64_t net_to_host_order(int64_t x) {
return ntohq(x);
}
/** @overload */
inline uint64_t net_to_host_order(uint64_t x) {
return ntohq(x);
}
#endif
/** @overload */
inline double net_to_host_order(float x) {
return host_to_net_order(x);
}
/** @overload */
inline double net_to_host_order(double x) {
return host_to_net_order(x);
}
template <typename T> struct make_aliasable {};
#define MAKE_ALIASABLE(T) template <> struct make_aliasable<T> { typedef T type __attribute__((__may_alias__)); }
MAKE_ALIASABLE(unsigned char);
MAKE_ALIASABLE(signed char);
MAKE_ALIASABLE(char);
MAKE_ALIASABLE(unsigned short);
MAKE_ALIASABLE(short);
MAKE_ALIASABLE(int);
MAKE_ALIASABLE(unsigned);
MAKE_ALIASABLE(long);
MAKE_ALIASABLE(unsigned long);
MAKE_ALIASABLE(long long);
MAKE_ALIASABLE(unsigned long long);
MAKE_ALIASABLE(float);
MAKE_ALIASABLE(double);
#undef MAKE_ALIASABLE
template <typename T>
inline char* write_in_host_order(char* s, T x) {
#if HAVE_INDIFFERENT_ALIGNMENT
*reinterpret_cast<typename make_aliasable<T>::type*>(s) = x;
#else
memcpy(s, &x, sizeof(x));
#endif
return s + sizeof(x);
}
template <typename T>
inline uint8_t* write_in_host_order(uint8_t* s, T x) {
return reinterpret_cast<uint8_t*>
(write_in_host_order(reinterpret_cast<char*>(s), x));
}
template <typename T>
inline T read_in_host_order(const char* s) {
#if HAVE_INDIFFERENT_ALIGNMENT
return *reinterpret_cast<const typename make_aliasable<T>::type*>(s);
#else
T x;
memcpy(&x, s, sizeof(x));
return x;
#endif
}
template <typename T>
inline T read_in_host_order(const uint8_t* s) {
return read_in_host_order<T>(reinterpret_cast<const char*>(s));
}
template <typename T>
inline char* write_in_net_order(char* s, T x) {
return write_in_host_order<T>(s, host_to_net_order(x));
}
template <typename T>
inline uint8_t* write_in_net_order(uint8_t* s, T x) {
return reinterpret_cast<uint8_t*>
(write_in_net_order(reinterpret_cast<char*>(s), x));
}
template <typename T>
inline T read_in_net_order(const char* s) {
return net_to_host_order(read_in_host_order<T>(s));
}
template <typename T>
inline T read_in_net_order(const uint8_t* s) {
return read_in_net_order<T>(reinterpret_cast<const char*>(s));
}
inline uint64_t read_pmc(uint32_t ecx) {
uint32_t a, d;
__asm __volatile("rdpmc" : "=a"(a), "=d"(d) : "c"(ecx));
return ((uint64_t)a) | (((uint64_t)d) << 32);
}
inline uint64_t read_tsc(void)
{
uint32_t low, high;
asm volatile("rdtsc" : "=a" (low), "=d" (high));
return ((uint64_t)low) | (((uint64_t)high) << 32);
}
template <typename T>
inline int compare(T a, T b) {
if (a == b)
return 0;
else
return a < b ? -1 : 1;
}
/** Type traits **/
namespace mass {
template <typename T> struct type_synonym {
typedef T type;
};
#if HAVE_CXX_TEMPLATE_ALIAS && HAVE_TYPE_TRAITS
template <typename T, T V>
using integral_constant = std::integral_constant<T, V>;
typedef std::true_type true_type;
typedef std::false_type false_type;
#else
template <typename T, T V>