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authorTimothy J Fontaine <tjfontaine@gmail.com>2013-10-22 15:14:25 -0700
committerTimothy J Fontaine <tjfontaine@gmail.com>2013-10-23 09:17:31 -0700
commita53c763c16eeabb0901a05dbcf38a72fa96d2f26 (patch)
tree309bf250e1521cedf0e945d7a7629db511e64498 /deps/v8/src/utils
parent54910044b33a6405c72ad085915a55c575c027fc (diff)
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v8: upgrade 3.21.18.3
Diffstat (limited to 'deps/v8/src/utils')
-rw-r--r--deps/v8/src/utils/random-number-generator.cc136
-rw-r--r--deps/v8/src/utils/random-number-generator.h106
2 files changed, 242 insertions, 0 deletions
diff --git a/deps/v8/src/utils/random-number-generator.cc b/deps/v8/src/utils/random-number-generator.cc
new file mode 100644
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+++ b/deps/v8/src/utils/random-number-generator.cc
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+// Copyright 2013 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+// * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following
+// disclaimer in the documentation and/or other materials provided
+// with the distribution.
+// * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived
+// from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#include "utils/random-number-generator.h"
+
+#include <cstdio>
+
+#include "flags.h"
+#include "platform/mutex.h"
+#include "platform/time.h"
+#include "utils.h"
+
+namespace v8 {
+namespace internal {
+
+static LazyMutex entropy_mutex = LAZY_MUTEX_INITIALIZER;
+static RandomNumberGenerator::EntropySource entropy_source = NULL;
+
+
+// static
+void RandomNumberGenerator::SetEntropySource(EntropySource source) {
+ LockGuard<Mutex> lock_guard(entropy_mutex.Pointer());
+ entropy_source = source;
+}
+
+
+RandomNumberGenerator::RandomNumberGenerator() {
+ // Check --random-seed flag first.
+ if (FLAG_random_seed != 0) {
+ SetSeed(FLAG_random_seed);
+ return;
+ }
+
+ // Check if embedder supplied an entropy source.
+ { LockGuard<Mutex> lock_guard(entropy_mutex.Pointer());
+ if (entropy_source != NULL) {
+ int64_t seed;
+ if (entropy_source(reinterpret_cast<unsigned char*>(&seed),
+ sizeof(seed))) {
+ SetSeed(seed);
+ return;
+ }
+ }
+ }
+
+ // Gather entropy from /dev/urandom if available.
+ FILE* fp = fopen("/dev/urandom", "rb");
+ if (fp != NULL) {
+ int64_t seed;
+ size_t n = fread(&seed, sizeof(seed), 1, fp);
+ fclose(fp);
+ if (n == 1) {
+ SetSeed(seed);
+ return;
+ }
+ }
+
+ // We cannot assume that random() or rand() were seeded
+ // properly, so instead of relying on random() or rand(),
+ // we just seed our PRNG using timing data as fallback.
+ int64_t seed = Time::NowFromSystemTime().ToInternalValue() << 24;
+ seed ^= TimeTicks::HighResNow().ToInternalValue() << 16;
+ seed ^= TimeTicks::Now().ToInternalValue() << 8;
+ SetSeed(seed);
+}
+
+
+int RandomNumberGenerator::NextInt(int max) {
+ ASSERT_LE(0, max);
+
+ // Fast path if max is a power of 2.
+ if (IsPowerOf2(max)) {
+ return static_cast<int>((max * static_cast<int64_t>(Next(31))) >> 31);
+ }
+
+ while (true) {
+ int rnd = Next(31);
+ int val = rnd % max;
+ if (rnd - val + (max - 1) >= 0) {
+ return val;
+ }
+ }
+}
+
+
+double RandomNumberGenerator::NextDouble() {
+ return ((static_cast<int64_t>(Next(26)) << 27) + Next(27)) /
+ static_cast<double>(static_cast<int64_t>(1) << 53);
+}
+
+
+void RandomNumberGenerator::NextBytes(void* buffer, size_t buflen) {
+ for (size_t n = 0; n < buflen; ++n) {
+ static_cast<uint8_t*>(buffer)[n] = static_cast<uint8_t>(Next(8));
+ }
+}
+
+
+int RandomNumberGenerator::Next(int bits) {
+ ASSERT_LT(0, bits);
+ ASSERT_GE(32, bits);
+ int64_t seed = (seed_ * kMultiplier + kAddend) & kMask;
+ seed_ = seed;
+ return static_cast<int>(seed >> (48 - bits));
+}
+
+
+void RandomNumberGenerator::SetSeed(int64_t seed) {
+ seed_ = (seed ^ kMultiplier) & kMask;
+}
+
+} } // namespace v8::internal
diff --git a/deps/v8/src/utils/random-number-generator.h b/deps/v8/src/utils/random-number-generator.h
new file mode 100644
index 0000000000..bd7dca7e65
--- /dev/null
+++ b/deps/v8/src/utils/random-number-generator.h
@@ -0,0 +1,106 @@
+// Copyright 2013 the V8 project authors. All rights reserved.
+// Redistribution and use in source and binary forms, with or without
+// modification, are permitted provided that the following conditions are
+// met:
+//
+// * Redistributions of source code must retain the above copyright
+// notice, this list of conditions and the following disclaimer.
+// * Redistributions in binary form must reproduce the above
+// copyright notice, this list of conditions and the following
+// disclaimer in the documentation and/or other materials provided
+// with the distribution.
+// * Neither the name of Google Inc. nor the names of its
+// contributors may be used to endorse or promote products derived
+// from this software without specific prior written permission.
+//
+// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+// "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+// LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+// A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+// OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+// SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+// LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+// DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+// THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+// (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+// OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+
+#ifndef V8_UTILS_RANDOM_NUMBER_GENERATOR_H_
+#define V8_UTILS_RANDOM_NUMBER_GENERATOR_H_
+
+#include "globals.h"
+
+namespace v8 {
+namespace internal {
+
+// -----------------------------------------------------------------------------
+// RandomNumberGenerator
+//
+// This class is used to generate a stream of pseudorandom numbers. The class
+// uses a 48-bit seed, which is modified using a linear congruential formula.
+// (See Donald Knuth, The Art of Computer Programming, Volume 3, Section 3.2.1.)
+// If two instances of RandomNumberGenerator are created with the same seed, and
+// the same sequence of method calls is made for each, they will generate and
+// return identical sequences of numbers.
+// This class is neither reentrant nor threadsafe.
+
+class RandomNumberGenerator V8_FINAL {
+ public:
+ // EntropySource is used as a callback function when V8 needs a source of
+ // entropy.
+ typedef bool (*EntropySource)(unsigned char* buffer, size_t buflen);
+ static void SetEntropySource(EntropySource entropy_source);
+
+ RandomNumberGenerator();
+ explicit RandomNumberGenerator(int64_t seed) { SetSeed(seed); }
+
+ // Returns the next pseudorandom, uniformly distributed int value from this
+ // random number generator's sequence. The general contract of |NextInt()| is
+ // that one int value is pseudorandomly generated and returned.
+ // All 2^32 possible integer values are produced with (approximately) equal
+ // probability.
+ V8_INLINE int NextInt() V8_WARN_UNUSED_RESULT {
+ return Next(32);
+ }
+
+ // Returns a pseudorandom, uniformly distributed int value between 0
+ // (inclusive) and the specified max value (exclusive), drawn from this random
+ // number generator's sequence. The general contract of |NextInt(int)| is that
+ // one int value in the specified range is pseudorandomly generated and
+ // returned. All max possible int values are produced with (approximately)
+ // equal probability.
+ int NextInt(int max) V8_WARN_UNUSED_RESULT;
+
+ // Returns the next pseudorandom, uniformly distributed boolean value from
+ // this random number generator's sequence. The general contract of
+ // |NextBoolean()| is that one boolean value is pseudorandomly generated and
+ // returned. The values true and false are produced with (approximately) equal
+ // probability.
+ V8_INLINE bool NextBool() V8_WARN_UNUSED_RESULT {
+ return Next(1) != 0;
+ }
+
+ // Returns the next pseudorandom, uniformly distributed double value between
+ // 0.0 and 1.0 from this random number generator's sequence.
+ // The general contract of |NextDouble()| is that one double value, chosen
+ // (approximately) uniformly from the range 0.0 (inclusive) to 1.0
+ // (exclusive), is pseudorandomly generated and returned.
+ double NextDouble() V8_WARN_UNUSED_RESULT;
+
+ // Fills the elements of a specified array of bytes with random numbers.
+ void NextBytes(void* buffer, size_t buflen);
+
+ private:
+ static const int64_t kMultiplier = V8_2PART_UINT64_C(0x5, deece66d);
+ static const int64_t kAddend = 0xb;
+ static const int64_t kMask = V8_2PART_UINT64_C(0xffff, ffffffff);
+
+ int Next(int bits) V8_WARN_UNUSED_RESULT;
+ void SetSeed(int64_t seed);
+
+ int64_t seed_;
+};
+
+} } // namespace v8::internal
+
+#endif // V8_UTILS_RANDOM_NUMBER_GENERATOR_H_