/*
- * Copyright 2014 Facebook, Inc.
+ * Copyright 2015 Facebook, Inc.
*
* Licensed under the Apache License, Version 2.0 (the "License");
* you may not use this file except in compliance with the License.
#ifndef FOLLY_BITS_H_
#define FOLLY_BITS_H_
-#include "folly/Portability.h"
-
-#ifndef __GNUC__
-#error GCC required
-#endif
-
-#ifndef __clang__
+#if !defined(__clang__) && !defined(_MSC_VER)
#define FOLLY_INTRINSIC_CONSTEXPR constexpr
#else
-// Unlike GCC, in Clang (as of 3.2) intrinsics aren't constexpr.
+// GCC is the only compiler with intrinsics constexpr.
#define FOLLY_INTRINSIC_CONSTEXPR const
#endif
-#ifndef FOLLY_NO_CONFIG
-#include "folly/folly-config.h"
-#endif
+#include <folly/Portability.h>
-#include "folly/detail/BitsDetail.h"
-#include "folly/detail/BitIteratorDetail.h"
-#include "folly/Likely.h"
+#include <folly/detail/BitsDetail.h>
+#include <folly/detail/BitIteratorDetail.h>
+#include <folly/Likely.h>
#if FOLLY_HAVE_BYTESWAP_H
# include <byteswap.h>
#endif
+#ifdef _MSC_VER
+# include <intrin.h>
+# pragma intrinsic(_BitScanForward)
+# pragma intrinsic(_BitScanForward64)
+# pragma intrinsic(_BitScanReverse)
+# pragma intrinsic(_BitScanReverse64)
+#endif
+
#include <cassert>
#include <cinttypes>
#include <iterator>
sizeof(T) <= sizeof(unsigned int)),
unsigned int>::type
findFirstSet(T x) {
+#ifdef _MSC_VER
+ unsigned long index;
+ return _BitScanForward(&index, x) ? index : 0;
+#else
return __builtin_ffs(x);
+#endif
}
template <class T>
sizeof(T) <= sizeof(unsigned long)),
unsigned int>::type
findFirstSet(T x) {
+#ifdef _MSC_VER
+ unsigned long index;
+ return _BitScanForward(&index, x) ? index : 0;
+#else
return __builtin_ffsl(x);
+#endif
}
template <class T>
sizeof(T) <= sizeof(unsigned long long)),
unsigned int>::type
findFirstSet(T x) {
+#ifdef _MSC_VER
+ unsigned long index;
+ return _BitScanForward64(&index, x) ? index : 0;
+#else
return __builtin_ffsll(x);
+#endif
}
template <class T>
sizeof(T) <= sizeof(unsigned int)),
unsigned int>::type
findLastSet(T x) {
+#ifdef _MSC_VER
+ unsigned long index;
+ int clz;
+ if (_BitScanReverse(&index, x)) {
+ clz = static_cast<int>(31 - index);
+ } else {
+ clz = 32;
+ }
+ return x ? 8 * sizeof(unsigned int) - clz : 0;
+#else
return x ? 8 * sizeof(unsigned int) - __builtin_clz(x) : 0;
+#endif
}
template <class T>
sizeof(T) <= sizeof(unsigned long)),
unsigned int>::type
findLastSet(T x) {
+#ifdef _MSC_VER
+ unsigned long index;
+ int clz;
+ if (_BitScanReverse(&index, x)) {
+ clz = static_cast<int>(31 - index);
+ } else {
+ clz = 32;
+ }
+ return x ? 8 * sizeof(unsigned int) - clz : 0;
+#else
return x ? 8 * sizeof(unsigned long) - __builtin_clzl(x) : 0;
+#endif
}
template <class T>
sizeof(T) <= sizeof(unsigned long long)),
unsigned int>::type
findLastSet(T x) {
+#ifdef _MSC_VER
+ unsigned long index;
+ unsigned long long clz;
+ if (_BitScanReverse(&index, x)) {
+ clz = static_cast<unsigned long long>(63 - index);
+ } else {
+ clz = 64;
+ }
+ return x ? 8 * sizeof(unsigned long long) - clz : 0;
+#else
return x ? 8 * sizeof(unsigned long long) - __builtin_clzll(x) : 0;
+#endif
}
template <class T>
static T swap(T x);
};
+#ifndef _MSC_VER
+
/**
* If we have the bswap_16 macro from byteswap.h, use it; otherwise, provide our
* own definition.
}
#endif
+#endif
+
#define FB_GEN(t, fn) \
template<> inline t EndianIntBase<t>::swap(t x) { return fn(x); }
// __builtin_bswap16 for some reason, so we have to provide our own.
FB_GEN( int8_t,)
FB_GEN(uint8_t,)
+#ifdef _MSC_VER
+FB_GEN( int64_t, _byteswap_uint64)
+FB_GEN(uint64_t, _byteswap_uint64)
+FB_GEN( int32_t, _byteswap_ulong)
+FB_GEN(uint32_t, _byteswap_ulong)
+FB_GEN( int16_t, _byteswap_ushort)
+FB_GEN(uint16_t, _byteswap_ushort)
+#else
FB_GEN( int64_t, __builtin_bswap64)
FB_GEN(uint64_t, __builtin_bswap64)
FB_GEN( int32_t, __builtin_bswap32)
FB_GEN(uint32_t, __builtin_bswap32)
FB_GEN( int16_t, our_bswap16)
FB_GEN(uint16_t, our_bswap16)
+#endif
#undef FB_GEN
return detail::EndianInt<T>::little(x);
}
+#if !defined(__ANDROID__)
FB_GEN(64)
FB_GEN(32)
FB_GEN(16)
FB_GEN(8)
+#endif
};
#undef FB_GEN
/**
* Return the number of bits in an element of the underlying iterator.
*/
- static size_t bitsPerBlock() {
+ static unsigned int bitsPerBlock() {
return std::numeric_limits<
typename std::make_unsigned<
typename std::iterator_traits<BaseIter>::value_type
ssize_t distance_to(const BitIterator& other) const {
return
(other.base_reference() - this->base_reference()) * bitsPerBlock() +
- (other.bitOffset_ - bitOffset_);
+ other.bitOffset_ - bitOffset_;
}
- ssize_t bitOffset_;
+ unsigned int bitOffset_;
};
/**
/**
* Representation of an unaligned value of a POD type.
*/
+FOLLY_PACK_PUSH
template <class T>
struct Unaligned<
T,
Unaligned() = default; // uninitialized
/* implicit */ Unaligned(T v) : value(v) { }
T value;
-} __attribute__((packed));
+} FOLLY_PACK_ATTR;
+FOLLY_PACK_POP
/**
* Read an unaligned value of type T and return it.