int128.h
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1 //
2 // Copyright 2017 The Abseil Authors.
3 //
4 // Licensed under the Apache License, Version 2.0 (the "License");
5 // you may not use this file except in compliance with the License.
6 // You may obtain a copy of the License at
7 //
8 // https://www.apache.org/licenses/LICENSE-2.0
9 //
10 // Unless required by applicable law or agreed to in writing, software
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13 // See the License for the specific language governing permissions and
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15 //
16 // -----------------------------------------------------------------------------
17 // File: int128.h
18 // -----------------------------------------------------------------------------
19 //
20 // This header file defines 128-bit integer types.
21 //
22 // Currently, this file defines `uint128`, an unsigned 128-bit integer; a signed
23 // 128-bit integer is forthcoming.
24 
25 #ifndef ABSL_NUMERIC_INT128_H_
26 #define ABSL_NUMERIC_INT128_H_
27 
28 #include <cassert>
29 #include <cmath>
30 #include <cstdint>
31 #include <cstring>
32 #include <iosfwd>
33 #include <limits>
34 #include <utility>
35 
36 #include "absl/base/config.h"
37 #include "absl/base/macros.h"
38 #include "absl/base/port.h"
39 
40 #if defined(_MSC_VER)
41 // In very old versions of MSVC and when the /Zc:wchar_t flag is off, wchar_t is
42 // a typedef for unsigned short. Otherwise wchar_t is mapped to the __wchar_t
43 // builtin type. We need to make sure not to define operator wchar_t()
44 // alongside operator unsigned short() in these instances.
45 #define ABSL_INTERNAL_WCHAR_T __wchar_t
46 #if defined(_M_X64)
47 #include <intrin.h>
48 #pragma intrinsic(_umul128)
49 #endif // defined(_M_X64)
50 #else // defined(_MSC_VER)
51 #define ABSL_INTERNAL_WCHAR_T wchar_t
52 #endif // defined(_MSC_VER)
53 
54 namespace absl {
55 
56 // uint128
57 //
58 // An unsigned 128-bit integer type. The API is meant to mimic an intrinsic type
59 // as closely as is practical, including exhibiting undefined behavior in
60 // analogous cases (e.g. division by zero). This type is intended to be a
61 // drop-in replacement once C++ supports an intrinsic `uint128_t` type; when
62 // that occurs, existing well-behaved uses of `uint128` will continue to work
63 // using that new type.
64 //
65 // Note: code written with this type will continue to compile once `uint128_t`
66 // is introduced, provided the replacement helper functions
67 // `Uint128(Low|High)64()` and `MakeUint128()` are made.
68 //
69 // A `uint128` supports the following:
70 //
71 // * Implicit construction from integral types
72 // * Explicit conversion to integral types
73 //
74 // Additionally, if your compiler supports `__int128`, `uint128` is
75 // interoperable with that type. (Abseil checks for this compatibility through
76 // the `ABSL_HAVE_INTRINSIC_INT128` macro.)
77 //
78 // However, a `uint128` differs from intrinsic integral types in the following
79 // ways:
80 //
81 // * Errors on implicit conversions that do not preserve value (such as
82 // loss of precision when converting to float values).
83 // * Requires explicit construction from and conversion to floating point
84 // types.
85 // * Conversion to integral types requires an explicit static_cast() to
86 // mimic use of the `-Wnarrowing` compiler flag.
87 // * The alignment requirement of `uint128` may differ from that of an
88 // intrinsic 128-bit integer type depending on platform and build
89 // configuration.
90 //
91 // Example:
92 //
93 // float y = absl::Uint128Max(); // Error. uint128 cannot be implicitly
94 // // converted to float.
95 //
96 // absl::uint128 v;
97 // uint64_t i = v; // Error
98 // uint64_t i = static_cast<uint64_t>(v); // OK
99 //
100 class
101 #if defined(ABSL_HAVE_INTRINSIC_INT128)
102  alignas(unsigned __int128)
103 #endif // ABSL_HAVE_INTRINSIC_INT128
104  uint128 {
105  public:
106  uint128() = default;
107 
108  // Constructors from arithmetic types
109  constexpr uint128(int v); // NOLINT(runtime/explicit)
110  constexpr uint128(unsigned int v); // NOLINT(runtime/explicit)
111  constexpr uint128(long v); // NOLINT(runtime/int)
112  constexpr uint128(unsigned long v); // NOLINT(runtime/int)
113  constexpr uint128(long long v); // NOLINT(runtime/int)
114  constexpr uint128(unsigned long long v); // NOLINT(runtime/int)
115 #ifdef ABSL_HAVE_INTRINSIC_INT128
116  constexpr uint128(__int128 v); // NOLINT(runtime/explicit)
117  constexpr uint128(unsigned __int128 v); // NOLINT(runtime/explicit)
118 #endif // ABSL_HAVE_INTRINSIC_INT128
119  explicit uint128(float v);
120  explicit uint128(double v);
121  explicit uint128(long double v);
122 
123  // Assignment operators from arithmetic types
124  uint128& operator=(int v);
125  uint128& operator=(unsigned int v);
126  uint128& operator=(long v); // NOLINT(runtime/int)
127  uint128& operator=(unsigned long v); // NOLINT(runtime/int)
128  uint128& operator=(long long v); // NOLINT(runtime/int)
129  uint128& operator=(unsigned long long v); // NOLINT(runtime/int)
130 #ifdef ABSL_HAVE_INTRINSIC_INT128
131  uint128& operator=(__int128 v);
132  uint128& operator=(unsigned __int128 v);
133 #endif // ABSL_HAVE_INTRINSIC_INT128
134 
135  // Conversion operators to other arithmetic types
136  constexpr explicit operator bool() const;
137  constexpr explicit operator char() const;
138  constexpr explicit operator signed char() const;
139  constexpr explicit operator unsigned char() const;
140  constexpr explicit operator char16_t() const;
141  constexpr explicit operator char32_t() const;
142  constexpr explicit operator ABSL_INTERNAL_WCHAR_T() const;
143  constexpr explicit operator short() const; // NOLINT(runtime/int)
144  // NOLINTNEXTLINE(runtime/int)
145  constexpr explicit operator unsigned short() const;
146  constexpr explicit operator int() const;
147  constexpr explicit operator unsigned int() const;
148  constexpr explicit operator long() const; // NOLINT(runtime/int)
149  // NOLINTNEXTLINE(runtime/int)
150  constexpr explicit operator unsigned long() const;
151  // NOLINTNEXTLINE(runtime/int)
152  constexpr explicit operator long long() const;
153  // NOLINTNEXTLINE(runtime/int)
154  constexpr explicit operator unsigned long long() const;
155 #ifdef ABSL_HAVE_INTRINSIC_INT128
156  constexpr explicit operator __int128() const;
157  constexpr explicit operator unsigned __int128() const;
158 #endif // ABSL_HAVE_INTRINSIC_INT128
159  explicit operator float() const;
160  explicit operator double() const;
161  explicit operator long double() const;
162 
163  // Trivial copy constructor, assignment operator and destructor.
164 
165  // Arithmetic operators.
166  uint128& operator+=(uint128 other);
167  uint128& operator-=(uint128 other);
168  uint128& operator*=(uint128 other);
169  // Long division/modulo for uint128.
170  uint128& operator/=(uint128 other);
171  uint128& operator%=(uint128 other);
172  uint128 operator++(int);
173  uint128 operator--(int);
174  uint128& operator<<=(int);
175  uint128& operator>>=(int);
176  uint128& operator&=(uint128 other);
177  uint128& operator|=(uint128 other);
178  uint128& operator^=(uint128 other);
179  uint128& operator++();
180  uint128& operator--();
181 
182  // Uint128Low64()
183  //
184  // Returns the lower 64-bit value of a `uint128` value.
185  friend constexpr uint64_t Uint128Low64(uint128 v);
186 
187  // Uint128High64()
188  //
189  // Returns the higher 64-bit value of a `uint128` value.
190  friend constexpr uint64_t Uint128High64(uint128 v);
191 
192  // MakeUInt128()
193  //
194  // Constructs a `uint128` numeric value from two 64-bit unsigned integers.
195  // Note that this factory function is the only way to construct a `uint128`
196  // from integer values greater than 2^64.
197  //
198  // Example:
199  //
200  // absl::uint128 big = absl::MakeUint128(1, 0);
201  friend constexpr uint128 MakeUint128(uint64_t high, uint64_t low);
202 
203  // Uint128Max()
204  //
205  // Returns the highest value for a 128-bit unsigned integer.
206  friend constexpr uint128 Uint128Max();
207 
208  // Support for absl::Hash.
209  template <typename H>
210  friend H AbslHashValue(H h, uint128 v) {
211  return H::combine(std::move(h), Uint128High64(v), Uint128Low64(v));
212  }
213 
214  private:
215  constexpr uint128(uint64_t high, uint64_t low);
216 
217  // TODO(strel) Update implementation to use __int128 once all users of
218  // uint128 are fixed to not depend on alignof(uint128) == 8. Also add
219  // alignas(16) to class definition to keep alignment consistent across
220  // platforms.
221 #if defined(ABSL_IS_LITTLE_ENDIAN)
222  uint64_t lo_;
223  uint64_t hi_;
224 #elif defined(ABSL_IS_BIG_ENDIAN)
225  uint64_t hi_;
226  uint64_t lo_;
227 #else // byte order
228 #error "Unsupported byte order: must be little-endian or big-endian."
229 #endif // byte order
230 };
231 
232 // Prefer to use the constexpr `Uint128Max()`.
233 //
234 // TODO(absl-team) deprecate kuint128max once migration tool is released.
235 extern const uint128 kuint128max;
236 
237 // allow uint128 to be logged
238 std::ostream& operator<<(std::ostream& os, uint128 v);
239 
240 // TODO(strel) add operator>>(std::istream&, uint128)
241 
242 constexpr uint128 Uint128Max() {
243  return uint128((std::numeric_limits<uint64_t>::max)(),
244  (std::numeric_limits<uint64_t>::max)());
245 }
246 
247 } // namespace absl
248 
249 // Specialized numeric_limits for uint128.
250 namespace std {
251 template <>
252 class numeric_limits<absl::uint128> {
253  public:
254  static constexpr bool is_specialized = true;
255  static constexpr bool is_signed = false;
256  static constexpr bool is_integer = true;
257  static constexpr bool is_exact = true;
258  static constexpr bool has_infinity = false;
259  static constexpr bool has_quiet_NaN = false;
260  static constexpr bool has_signaling_NaN = false;
261  static constexpr float_denorm_style has_denorm = denorm_absent;
262  static constexpr bool has_denorm_loss = false;
263  static constexpr float_round_style round_style = round_toward_zero;
264  static constexpr bool is_iec559 = false;
265  static constexpr bool is_bounded = true;
266  static constexpr bool is_modulo = true;
267  static constexpr int digits = 128;
268  static constexpr int digits10 = 38;
269  static constexpr int max_digits10 = 0;
270  static constexpr int radix = 2;
271  static constexpr int min_exponent = 0;
272  static constexpr int min_exponent10 = 0;
273  static constexpr int max_exponent = 0;
274  static constexpr int max_exponent10 = 0;
275 #ifdef ABSL_HAVE_INTRINSIC_INT128
276  static constexpr bool traps = numeric_limits<unsigned __int128>::traps;
277 #else // ABSL_HAVE_INTRINSIC_INT128
278  static constexpr bool traps = numeric_limits<uint64_t>::traps;
279 #endif // ABSL_HAVE_INTRINSIC_INT128
280  static constexpr bool tinyness_before = false;
281 
282  static constexpr absl::uint128 (min)() { return 0; }
283  static constexpr absl::uint128 lowest() { return 0; }
284  static constexpr absl::uint128 (max)() { return absl::Uint128Max(); }
285  static constexpr absl::uint128 epsilon() { return 0; }
286  static constexpr absl::uint128 round_error() { return 0; }
287  static constexpr absl::uint128 infinity() { return 0; }
288  static constexpr absl::uint128 quiet_NaN() { return 0; }
289  static constexpr absl::uint128 signaling_NaN() { return 0; }
290  static constexpr absl::uint128 denorm_min() { return 0; }
291 };
292 } // namespace std
293 
294 // TODO(absl-team): Implement signed 128-bit type
295 
296 // --------------------------------------------------------------------------
297 // Implementation details follow
298 // --------------------------------------------------------------------------
299 namespace absl {
300 
301 constexpr uint128 MakeUint128(uint64_t high, uint64_t low) {
302  return uint128(high, low);
303 }
304 
305 // Assignment from integer types.
306 
307 inline uint128& uint128::operator=(int v) { return *this = uint128(v); }
308 
309 inline uint128& uint128::operator=(unsigned int v) {
310  return *this = uint128(v);
311 }
312 
313 inline uint128& uint128::operator=(long v) { // NOLINT(runtime/int)
314  return *this = uint128(v);
315 }
316 
317 // NOLINTNEXTLINE(runtime/int)
318 inline uint128& uint128::operator=(unsigned long v) {
319  return *this = uint128(v);
320 }
321 
322 // NOLINTNEXTLINE(runtime/int)
323 inline uint128& uint128::operator=(long long v) {
324  return *this = uint128(v);
325 }
326 
327 // NOLINTNEXTLINE(runtime/int)
328 inline uint128& uint128::operator=(unsigned long long v) {
329  return *this = uint128(v);
330 }
331 
332 #ifdef ABSL_HAVE_INTRINSIC_INT128
333 inline uint128& uint128::operator=(__int128 v) {
334  return *this = uint128(v);
335 }
336 
337 inline uint128& uint128::operator=(unsigned __int128 v) {
338  return *this = uint128(v);
339 }
340 #endif // ABSL_HAVE_INTRINSIC_INT128
341 
342 // Arithmetic operators.
343 
344 uint128 operator<<(uint128 lhs, int amount);
345 uint128 operator>>(uint128 lhs, int amount);
346 uint128 operator+(uint128 lhs, uint128 rhs);
347 uint128 operator-(uint128 lhs, uint128 rhs);
348 uint128 operator*(uint128 lhs, uint128 rhs);
349 uint128 operator/(uint128 lhs, uint128 rhs);
350 uint128 operator%(uint128 lhs, uint128 rhs);
351 
352 inline uint128& uint128::operator<<=(int amount) {
353  *this = *this << amount;
354  return *this;
355 }
356 
357 inline uint128& uint128::operator>>=(int amount) {
358  *this = *this >> amount;
359  return *this;
360 }
361 
363  *this = *this + other;
364  return *this;
365 }
366 
368  *this = *this - other;
369  return *this;
370 }
371 
373  *this = *this * other;
374  return *this;
375 }
376 
378  *this = *this / other;
379  return *this;
380 }
381 
383  *this = *this % other;
384  return *this;
385 }
386 
387 constexpr uint64_t Uint128Low64(uint128 v) { return v.lo_; }
388 
389 constexpr uint64_t Uint128High64(uint128 v) { return v.hi_; }
390 
391 // Constructors from integer types.
392 
393 #if defined(ABSL_IS_LITTLE_ENDIAN)
394 
395 constexpr uint128::uint128(uint64_t high, uint64_t low)
396  : lo_{low}, hi_{high} {}
397 
398 constexpr uint128::uint128(int v)
399  : lo_{static_cast<uint64_t>(v)},
400  hi_{v < 0 ? (std::numeric_limits<uint64_t>::max)() : 0} {}
401 constexpr uint128::uint128(long v) // NOLINT(runtime/int)
402  : lo_{static_cast<uint64_t>(v)},
403  hi_{v < 0 ? (std::numeric_limits<uint64_t>::max)() : 0} {}
404 constexpr uint128::uint128(long long v) // NOLINT(runtime/int)
405  : lo_{static_cast<uint64_t>(v)},
406  hi_{v < 0 ? (std::numeric_limits<uint64_t>::max)() : 0} {}
407 
408 constexpr uint128::uint128(unsigned int v) : lo_{v}, hi_{0} {}
409 // NOLINTNEXTLINE(runtime/int)
410 constexpr uint128::uint128(unsigned long v) : lo_{v}, hi_{0} {}
411 // NOLINTNEXTLINE(runtime/int)
412 constexpr uint128::uint128(unsigned long long v) : lo_{v}, hi_{0} {}
413 
414 #ifdef ABSL_HAVE_INTRINSIC_INT128
415 constexpr uint128::uint128(__int128 v)
416  : lo_{static_cast<uint64_t>(v & ~uint64_t{0})},
417  hi_{static_cast<uint64_t>(static_cast<unsigned __int128>(v) >> 64)} {}
418 constexpr uint128::uint128(unsigned __int128 v)
419  : lo_{static_cast<uint64_t>(v & ~uint64_t{0})},
420  hi_{static_cast<uint64_t>(v >> 64)} {}
421 #endif // ABSL_HAVE_INTRINSIC_INT128
422 
423 #elif defined(ABSL_IS_BIG_ENDIAN)
424 
425 constexpr uint128::uint128(uint64_t high, uint64_t low)
426  : hi_{high}, lo_{low} {}
427 
428 constexpr uint128::uint128(int v)
429  : hi_{v < 0 ? (std::numeric_limits<uint64_t>::max)() : 0},
430  lo_{static_cast<uint64_t>(v)} {}
431 constexpr uint128::uint128(long v) // NOLINT(runtime/int)
432  : hi_{v < 0 ? (std::numeric_limits<uint64_t>::max)() : 0},
433  lo_{static_cast<uint64_t>(v)} {}
434 constexpr uint128::uint128(long long v) // NOLINT(runtime/int)
435  : hi_{v < 0 ? (std::numeric_limits<uint64_t>::max)() : 0},
436  lo_{static_cast<uint64_t>(v)} {}
437 
438 constexpr uint128::uint128(unsigned int v) : hi_{0}, lo_{v} {}
439 // NOLINTNEXTLINE(runtime/int)
440 constexpr uint128::uint128(unsigned long v) : hi_{0}, lo_{v} {}
441 // NOLINTNEXTLINE(runtime/int)
442 constexpr uint128::uint128(unsigned long long v) : hi_{0}, lo_{v} {}
443 
444 #ifdef ABSL_HAVE_INTRINSIC_INT128
445 constexpr uint128::uint128(__int128 v)
446  : hi_{static_cast<uint64_t>(static_cast<unsigned __int128>(v) >> 64)},
447  lo_{static_cast<uint64_t>(v & ~uint64_t{0})} {}
448 constexpr uint128::uint128(unsigned __int128 v)
449  : hi_{static_cast<uint64_t>(v >> 64)},
450  lo_{static_cast<uint64_t>(v & ~uint64_t{0})} {}
451 #endif // ABSL_HAVE_INTRINSIC_INT128
452 
453 #else // byte order
454 #error "Unsupported byte order: must be little-endian or big-endian."
455 #endif // byte order
456 
457 // Conversion operators to integer types.
458 
459 constexpr uint128::operator bool() const { return lo_ || hi_; }
460 
461 constexpr uint128::operator char() const { return static_cast<char>(lo_); }
462 
463 constexpr uint128::operator signed char() const {
464  return static_cast<signed char>(lo_);
465 }
466 
467 constexpr uint128::operator unsigned char() const {
468  return static_cast<unsigned char>(lo_);
469 }
470 
471 constexpr uint128::operator char16_t() const {
472  return static_cast<char16_t>(lo_);
473 }
474 
475 constexpr uint128::operator char32_t() const {
476  return static_cast<char32_t>(lo_);
477 }
478 
479 constexpr uint128::operator ABSL_INTERNAL_WCHAR_T() const {
480  return static_cast<ABSL_INTERNAL_WCHAR_T>(lo_);
481 }
482 
483 // NOLINTNEXTLINE(runtime/int)
484 constexpr uint128::operator short() const { return static_cast<short>(lo_); }
485 
486 constexpr uint128::operator unsigned short() const { // NOLINT(runtime/int)
487  return static_cast<unsigned short>(lo_); // NOLINT(runtime/int)
488 }
489 
490 constexpr uint128::operator int() const { return static_cast<int>(lo_); }
491 
492 constexpr uint128::operator unsigned int() const {
493  return static_cast<unsigned int>(lo_);
494 }
495 
496 // NOLINTNEXTLINE(runtime/int)
497 constexpr uint128::operator long() const { return static_cast<long>(lo_); }
498 
499 constexpr uint128::operator unsigned long() const { // NOLINT(runtime/int)
500  return static_cast<unsigned long>(lo_); // NOLINT(runtime/int)
501 }
502 
503 constexpr uint128::operator long long() const { // NOLINT(runtime/int)
504  return static_cast<long long>(lo_); // NOLINT(runtime/int)
505 }
506 
507 constexpr uint128::operator unsigned long long() const { // NOLINT(runtime/int)
508  return static_cast<unsigned long long>(lo_); // NOLINT(runtime/int)
509 }
510 
511 #ifdef ABSL_HAVE_INTRINSIC_INT128
512 constexpr uint128::operator __int128() const {
513  return (static_cast<__int128>(hi_) << 64) + lo_;
514 }
515 
516 constexpr uint128::operator unsigned __int128() const {
517  return (static_cast<unsigned __int128>(hi_) << 64) + lo_;
518 }
519 #endif // ABSL_HAVE_INTRINSIC_INT128
520 
521 // Conversion operators to floating point types.
522 
523 inline uint128::operator float() const {
524  return static_cast<float>(lo_) + std::ldexp(static_cast<float>(hi_), 64);
525 }
526 
527 inline uint128::operator double() const {
528  return static_cast<double>(lo_) + std::ldexp(static_cast<double>(hi_), 64);
529 }
530 
531 inline uint128::operator long double() const {
532  return static_cast<long double>(lo_) +
533  std::ldexp(static_cast<long double>(hi_), 64);
534 }
535 
536 // Comparison operators.
537 
538 inline bool operator==(uint128 lhs, uint128 rhs) {
539  return (Uint128Low64(lhs) == Uint128Low64(rhs) &&
540  Uint128High64(lhs) == Uint128High64(rhs));
541 }
542 
543 inline bool operator!=(uint128 lhs, uint128 rhs) {
544  return !(lhs == rhs);
545 }
546 
547 inline bool operator<(uint128 lhs, uint128 rhs) {
548  return (Uint128High64(lhs) == Uint128High64(rhs))
549  ? (Uint128Low64(lhs) < Uint128Low64(rhs))
550  : (Uint128High64(lhs) < Uint128High64(rhs));
551 }
552 
553 inline bool operator>(uint128 lhs, uint128 rhs) {
554  return (Uint128High64(lhs) == Uint128High64(rhs))
555  ? (Uint128Low64(lhs) > Uint128Low64(rhs))
556  : (Uint128High64(lhs) > Uint128High64(rhs));
557 }
558 
559 inline bool operator<=(uint128 lhs, uint128 rhs) {
560  return (Uint128High64(lhs) == Uint128High64(rhs))
561  ? (Uint128Low64(lhs) <= Uint128Low64(rhs))
562  : (Uint128High64(lhs) <= Uint128High64(rhs));
563 }
564 
565 inline bool operator>=(uint128 lhs, uint128 rhs) {
566  return (Uint128High64(lhs) == Uint128High64(rhs))
567  ? (Uint128Low64(lhs) >= Uint128Low64(rhs))
568  : (Uint128High64(lhs) >= Uint128High64(rhs));
569 }
570 
571 // Unary operators.
572 
573 inline uint128 operator-(uint128 val) {
574  uint64_t hi = ~Uint128High64(val);
575  uint64_t lo = ~Uint128Low64(val) + 1;
576  if (lo == 0) ++hi; // carry
577  return MakeUint128(hi, lo);
578 }
579 
580 inline bool operator!(uint128 val) {
581  return !Uint128High64(val) && !Uint128Low64(val);
582 }
583 
584 // Logical operators.
585 
586 inline uint128 operator~(uint128 val) {
587  return MakeUint128(~Uint128High64(val), ~Uint128Low64(val));
588 }
589 
590 inline uint128 operator|(uint128 lhs, uint128 rhs) {
591  return MakeUint128(Uint128High64(lhs) | Uint128High64(rhs),
592  Uint128Low64(lhs) | Uint128Low64(rhs));
593 }
594 
595 inline uint128 operator&(uint128 lhs, uint128 rhs) {
596  return MakeUint128(Uint128High64(lhs) & Uint128High64(rhs),
597  Uint128Low64(lhs) & Uint128Low64(rhs));
598 }
599 
600 inline uint128 operator^(uint128 lhs, uint128 rhs) {
601  return MakeUint128(Uint128High64(lhs) ^ Uint128High64(rhs),
602  Uint128Low64(lhs) ^ Uint128Low64(rhs));
603 }
604 
606  hi_ |= other.hi_;
607  lo_ |= other.lo_;
608  return *this;
609 }
610 
611 inline uint128& uint128::operator&=(uint128 other) {
612  hi_ &= other.hi_;
613  lo_ &= other.lo_;
614  return *this;
615 }
616 
618  hi_ ^= other.hi_;
619  lo_ ^= other.lo_;
620  return *this;
621 }
622 
623 // Arithmetic operators.
624 
625 inline uint128 operator<<(uint128 lhs, int amount) {
626  // uint64_t shifts of >= 64 are undefined, so we will need some
627  // special-casing.
628  if (amount < 64) {
629  if (amount != 0) {
630  return MakeUint128(
631  (Uint128High64(lhs) << amount) | (Uint128Low64(lhs) >> (64 - amount)),
632  Uint128Low64(lhs) << amount);
633  }
634  return lhs;
635  }
636  return MakeUint128(Uint128Low64(lhs) << (amount - 64), 0);
637 }
638 
639 inline uint128 operator>>(uint128 lhs, int amount) {
640  // uint64_t shifts of >= 64 are undefined, so we will need some
641  // special-casing.
642  if (amount < 64) {
643  if (amount != 0) {
644  return MakeUint128(Uint128High64(lhs) >> amount,
645  (Uint128Low64(lhs) >> amount) |
646  (Uint128High64(lhs) << (64 - amount)));
647  }
648  return lhs;
649  }
650  return MakeUint128(0, Uint128High64(lhs) >> (amount - 64));
651 }
652 
653 inline uint128 operator+(uint128 lhs, uint128 rhs) {
654  uint128 result = MakeUint128(Uint128High64(lhs) + Uint128High64(rhs),
655  Uint128Low64(lhs) + Uint128Low64(rhs));
656  if (Uint128Low64(result) < Uint128Low64(lhs)) { // check for carry
657  return MakeUint128(Uint128High64(result) + 1, Uint128Low64(result));
658  }
659  return result;
660 }
661 
662 inline uint128 operator-(uint128 lhs, uint128 rhs) {
663  uint128 result = MakeUint128(Uint128High64(lhs) - Uint128High64(rhs),
664  Uint128Low64(lhs) - Uint128Low64(rhs));
665  if (Uint128Low64(lhs) < Uint128Low64(rhs)) { // check for carry
666  return MakeUint128(Uint128High64(result) - 1, Uint128Low64(result));
667  }
668  return result;
669 }
670 
671 inline uint128 operator*(uint128 lhs, uint128 rhs) {
672 #if defined(ABSL_HAVE_INTRINSIC_INT128)
673  // TODO(strel) Remove once alignment issues are resolved and unsigned __int128
674  // can be used for uint128 storage.
675  return static_cast<unsigned __int128>(lhs) *
676  static_cast<unsigned __int128>(rhs);
677 #elif defined(_MSC_VER) && defined(_M_X64)
678  uint64_t carry;
679  uint64_t low = _umul128(Uint128Low64(lhs), Uint128Low64(rhs), &carry);
680  return MakeUint128(Uint128Low64(lhs) * Uint128High64(rhs) +
681  Uint128High64(lhs) * Uint128Low64(rhs) + carry,
682  low);
683 #else // ABSL_HAVE_INTRINSIC128
684  uint64_t a32 = Uint128Low64(lhs) >> 32;
685  uint64_t a00 = Uint128Low64(lhs) & 0xffffffff;
686  uint64_t b32 = Uint128Low64(rhs) >> 32;
687  uint64_t b00 = Uint128Low64(rhs) & 0xffffffff;
688  uint128 result =
690  Uint128Low64(lhs) * Uint128High64(rhs) + a32 * b32,
691  a00 * b00);
692  result += uint128(a32 * b00) << 32;
693  result += uint128(a00 * b32) << 32;
694  return result;
695 #endif // ABSL_HAVE_INTRINSIC128
696 }
697 
698 // Increment/decrement operators.
699 
701  uint128 tmp(*this);
702  *this += 1;
703  return tmp;
704 }
705 
707  uint128 tmp(*this);
708  *this -= 1;
709  return tmp;
710 }
711 
713  *this += 1;
714  return *this;
715 }
716 
718  *this -= 1;
719  return *this;
720 }
721 
722 #if defined(ABSL_HAVE_INTRINSIC_INT128)
723 #include "absl/numeric/int128_have_intrinsic.inc"
724 #else // ABSL_HAVE_INTRINSIC_INT128
725 #include "absl/numeric/int128_no_intrinsic.inc"
726 #endif // ABSL_HAVE_INTRINSIC_INT128
727 
728 } // namespace absl
729 
730 #undef ABSL_INTERNAL_WCHAR_T
731 
732 #endif // ABSL_NUMERIC_INT128_H_
int v
Definition: variant_test.cc:81
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autogenerated on Mon Feb 28 2022 21:31:19