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30 #ifndef GOOGLE_PROTOBUF_STUBS_INT128_H_
31 #define GOOGLE_PROTOBUF_STUBS_INT128_H_
32
33 #include <google/protobuf/stubs/common.h>
34
35 #include <iosfwd>
36
37 namespace google {
38 namespace protobuf {
39
40 struct uint128_pod;
41
42 // TODO(xiaofeng): Define GOOGLE_PROTOBUF_HAS_CONSTEXPR when constexpr is
43 // available.
44 #ifdef GOOGLE_PROTOBUF_HAS_CONSTEXPR
45 # define UINT128_CONSTEXPR constexpr
46 #else
47 # define UINT128_CONSTEXPR
48 #endif
49
50 // An unsigned 128-bit integer type. Thread-compatible.
51 class LIBPROTOBUF_EXPORT uint128 {
52 public:
53 UINT128_CONSTEXPR uint128(); // Sets to 0, but don't trust on this behavior.
54 UINT128_CONSTEXPR uint128(uint64 top, uint64 bottom);
55 #ifndef SWIG
56 UINT128_CONSTEXPR uint128(int bottom);
57 UINT128_CONSTEXPR uint128(uint32 bottom); // Top 96 bits = 0
58 #endif
59 UINT128_CONSTEXPR uint128(uint64 bottom); // hi_ = 0
60 UINT128_CONSTEXPR uint128(const uint128_pod &val);
61
62 // Trivial copy constructor, assignment operator and destructor.
63
64 void Initialize(uint64 top, uint64 bottom);
65
66 // Arithmetic operators.
67 uint128& operator+=(const uint128& b);
68 uint128& operator-=(const uint128& b);
69 uint128& operator*=(const uint128& b);
70 // Long division/modulo for uint128.
71 uint128& operator/=(const uint128& b);
72 uint128& operator%=(const uint128& b);
73 uint128 operator++(int);
74 uint128 operator--(int);
75 uint128& operator<<=(int);
76 uint128& operator>>=(int);
77 uint128& operator&=(const uint128& b);
78 uint128& operator|=(const uint128& b);
79 uint128& operator^=(const uint128& b);
80 uint128& operator++();
81 uint128& operator--();
82
83 friend uint64 Uint128Low64(const uint128& v);
84 friend uint64 Uint128High64(const uint128& v);
85
86 // We add "std::" to avoid including all of port.h.
87 LIBPROTOBUF_EXPORT friend std::ostream& operator<<(std::ostream& o,
88 const uint128& b);
89
90 private:
91 static void DivModImpl(uint128 dividend, uint128 divisor,
92 uint128* quotient_ret, uint128* remainder_ret);
93
94 // Little-endian memory order optimizations can benefit from
95 // having lo_ first, hi_ last.
96 // See util/endian/endian.h and Load128/Store128 for storing a uint128.
97 uint64 lo_;
98 uint64 hi_;
99
100 // Not implemented, just declared for catching automatic type conversions.
101 uint128(uint8);
102 uint128(uint16);
103 uint128(float v);
104 uint128(double v);
105 };
106
107 // This is a POD form of uint128 which can be used for static variables which
108 // need to be operated on as uint128.
109 struct uint128_pod {
110 // Note: The ordering of fields is different than 'class uint128' but the
111 // same as its 2-arg constructor. This enables more obvious initialization
112 // of static instances, which is the primary reason for this struct in the
113 // first place. This does not seem to defeat any optimizations wrt
114 // operations involving this struct.
115 uint64 hi;
116 uint64 lo;
117 };
118
119 LIBPROTOBUF_EXPORT extern const uint128_pod kuint128max;
120
121 // allow uint128 to be logged
122 LIBPROTOBUF_EXPORT extern std::ostream& operator<<(std::ostream& o,
123 const uint128& b);
124
125 // Methods to access low and high pieces of 128-bit value.
126 // Defined externally from uint128 to facilitate conversion
127 // to native 128-bit types when compilers support them.
Uint128Low64(const uint128 & v)128 inline uint64 Uint128Low64(const uint128& v) { return v.lo_; }
Uint128High64(const uint128 & v)129 inline uint64 Uint128High64(const uint128& v) { return v.hi_; }
130
131 // TODO: perhaps it would be nice to have int128, a signed 128-bit type?
132
133 // --------------------------------------------------------------------------
134 // Implementation details follow
135 // --------------------------------------------------------------------------
136 inline bool operator==(const uint128& lhs, const uint128& rhs) {
137 return (Uint128Low64(lhs) == Uint128Low64(rhs) &&
138 Uint128High64(lhs) == Uint128High64(rhs));
139 }
140 inline bool operator!=(const uint128& lhs, const uint128& rhs) {
141 return !(lhs == rhs);
142 }
143
uint128()144 inline UINT128_CONSTEXPR uint128::uint128() : lo_(0), hi_(0) {}
uint128(uint64 top,uint64 bottom)145 inline UINT128_CONSTEXPR uint128::uint128(uint64 top, uint64 bottom)
146 : lo_(bottom), hi_(top) {}
uint128(const uint128_pod & v)147 inline UINT128_CONSTEXPR uint128::uint128(const uint128_pod& v)
148 : lo_(v.lo), hi_(v.hi) {}
uint128(uint64 bottom)149 inline UINT128_CONSTEXPR uint128::uint128(uint64 bottom)
150 : lo_(bottom), hi_(0) {}
151 #ifndef SWIG
uint128(uint32 bottom)152 inline UINT128_CONSTEXPR uint128::uint128(uint32 bottom)
153 : lo_(bottom), hi_(0) {}
uint128(int bottom)154 inline UINT128_CONSTEXPR uint128::uint128(int bottom)
155 : lo_(bottom), hi_(static_cast<int64>((bottom < 0) ? -1 : 0)) {}
156 #endif
157
158 #undef UINT128_CONSTEXPR
159
Initialize(uint64 top,uint64 bottom)160 inline void uint128::Initialize(uint64 top, uint64 bottom) {
161 hi_ = top;
162 lo_ = bottom;
163 }
164
165 // Comparison operators.
166
167 #define CMP128(op) \
168 inline bool operator op(const uint128& lhs, const uint128& rhs) { \
169 return (Uint128High64(lhs) == Uint128High64(rhs)) ? \
170 (Uint128Low64(lhs) op Uint128Low64(rhs)) : \
171 (Uint128High64(lhs) op Uint128High64(rhs)); \
172 }
173
174 CMP128(<)
175 CMP128(>)
176 CMP128(>=)
177 CMP128(<=)
178
179 #undef CMP128
180
181 // Unary operators
182
183 inline uint128 operator-(const uint128& val) {
184 const uint64 hi_flip = ~Uint128High64(val);
185 const uint64 lo_flip = ~Uint128Low64(val);
186 const uint64 lo_add = lo_flip + 1;
187 if (lo_add < lo_flip) {
188 return uint128(hi_flip + 1, lo_add);
189 }
190 return uint128(hi_flip, lo_add);
191 }
192
193 inline bool operator!(const uint128& val) {
194 return !Uint128High64(val) && !Uint128Low64(val);
195 }
196
197 // Logical operators.
198
199 inline uint128 operator~(const uint128& val) {
200 return uint128(~Uint128High64(val), ~Uint128Low64(val));
201 }
202
203 #define LOGIC128(op) \
204 inline uint128 operator op(const uint128& lhs, const uint128& rhs) { \
205 return uint128(Uint128High64(lhs) op Uint128High64(rhs), \
206 Uint128Low64(lhs) op Uint128Low64(rhs)); \
207 }
208
209 LOGIC128(|)
210 LOGIC128(&)
211 LOGIC128(^)
212
213 #undef LOGIC128
214
215 #define LOGICASSIGN128(op) \
216 inline uint128& uint128::operator op(const uint128& other) { \
217 hi_ op other.hi_; \
218 lo_ op other.lo_; \
219 return *this; \
220 }
221
222 LOGICASSIGN128(|=)
223 LOGICASSIGN128(&=)
224 LOGICASSIGN128(^=)
225
226 #undef LOGICASSIGN128
227
228 // Shift operators.
229
230 inline uint128 operator<<(const uint128& val, int amount) {
231 // uint64 shifts of >= 64 are undefined, so we will need some special-casing.
232 if (amount < 64) {
233 if (amount == 0) {
234 return val;
235 }
236 uint64 new_hi = (Uint128High64(val) << amount) |
237 (Uint128Low64(val) >> (64 - amount));
238 uint64 new_lo = Uint128Low64(val) << amount;
239 return uint128(new_hi, new_lo);
240 } else if (amount < 128) {
241 return uint128(Uint128Low64(val) << (amount - 64), 0);
242 } else {
243 return uint128(0, 0);
244 }
245 }
246
247 inline uint128 operator>>(const uint128& val, int amount) {
248 // uint64 shifts of >= 64 are undefined, so we will need some special-casing.
249 if (amount < 64) {
250 if (amount == 0) {
251 return val;
252 }
253 uint64 new_hi = Uint128High64(val) >> amount;
254 uint64 new_lo = (Uint128Low64(val) >> amount) |
255 (Uint128High64(val) << (64 - amount));
256 return uint128(new_hi, new_lo);
257 } else if (amount < 128) {
258 return uint128(0, Uint128High64(val) >> (amount - 64));
259 } else {
260 return uint128(0, 0);
261 }
262 }
263
264 inline uint128& uint128::operator<<=(int amount) {
265 // uint64 shifts of >= 64 are undefined, so we will need some special-casing.
266 if (amount < 64) {
267 if (amount != 0) {
268 hi_ = (hi_ << amount) | (lo_ >> (64 - amount));
269 lo_ = lo_ << amount;
270 }
271 } else if (amount < 128) {
272 hi_ = lo_ << (amount - 64);
273 lo_ = 0;
274 } else {
275 hi_ = 0;
276 lo_ = 0;
277 }
278 return *this;
279 }
280
281 inline uint128& uint128::operator>>=(int amount) {
282 // uint64 shifts of >= 64 are undefined, so we will need some special-casing.
283 if (amount < 64) {
284 if (amount != 0) {
285 lo_ = (lo_ >> amount) | (hi_ << (64 - amount));
286 hi_ = hi_ >> amount;
287 }
288 } else if (amount < 128) {
289 lo_ = hi_ >> (amount - 64);
290 hi_ = 0;
291 } else {
292 lo_ = 0;
293 hi_ = 0;
294 }
295 return *this;
296 }
297
298 inline uint128 operator+(const uint128& lhs, const uint128& rhs) {
299 return uint128(lhs) += rhs;
300 }
301
302 inline uint128 operator-(const uint128& lhs, const uint128& rhs) {
303 return uint128(lhs) -= rhs;
304 }
305
306 inline uint128 operator*(const uint128& lhs, const uint128& rhs) {
307 return uint128(lhs) *= rhs;
308 }
309
310 inline uint128 operator/(const uint128& lhs, const uint128& rhs) {
311 return uint128(lhs) /= rhs;
312 }
313
314 inline uint128 operator%(const uint128& lhs, const uint128& rhs) {
315 return uint128(lhs) %= rhs;
316 }
317
318 inline uint128& uint128::operator+=(const uint128& b) {
319 hi_ += b.hi_;
320 uint64 lolo = lo_ + b.lo_;
321 if (lolo < lo_)
322 ++hi_;
323 lo_ = lolo;
324 return *this;
325 }
326
327 inline uint128& uint128::operator-=(const uint128& b) {
328 hi_ -= b.hi_;
329 if (b.lo_ > lo_)
330 --hi_;
331 lo_ -= b.lo_;
332 return *this;
333 }
334
335 inline uint128& uint128::operator*=(const uint128& b) {
336 uint64 a96 = hi_ >> 32;
337 uint64 a64 = hi_ & 0xffffffffu;
338 uint64 a32 = lo_ >> 32;
339 uint64 a00 = lo_ & 0xffffffffu;
340 uint64 b96 = b.hi_ >> 32;
341 uint64 b64 = b.hi_ & 0xffffffffu;
342 uint64 b32 = b.lo_ >> 32;
343 uint64 b00 = b.lo_ & 0xffffffffu;
344 // multiply [a96 .. a00] x [b96 .. b00]
345 // terms higher than c96 disappear off the high side
346 // terms c96 and c64 are safe to ignore carry bit
347 uint64 c96 = a96 * b00 + a64 * b32 + a32 * b64 + a00 * b96;
348 uint64 c64 = a64 * b00 + a32 * b32 + a00 * b64;
349 this->hi_ = (c96 << 32) + c64;
350 this->lo_ = 0;
351 // add terms after this one at a time to capture carry
352 *this += uint128(a32 * b00) << 32;
353 *this += uint128(a00 * b32) << 32;
354 *this += a00 * b00;
355 return *this;
356 }
357
358 inline uint128 uint128::operator++(int) {
359 uint128 tmp(*this);
360 *this += 1;
361 return tmp;
362 }
363
364 inline uint128 uint128::operator--(int) {
365 uint128 tmp(*this);
366 *this -= 1;
367 return tmp;
368 }
369
370 inline uint128& uint128::operator++() {
371 *this += 1;
372 return *this;
373 }
374
375 inline uint128& uint128::operator--() {
376 *this -= 1;
377 return *this;
378 }
379
380 } // namespace protobuf
381 } // namespace google
382
383 #endif // GOOGLE_PROTOBUF_STUBS_INT128_H_
384