1 files changed, 52 insertions, 0 deletions
diff --git a/deps/v8/test/cctest/test-strings.cc b/deps/v8/test/cctest/test-strings.cc
index d6591a09b9..310d93c04e 100644
--- a/deps/v8/test/cctest/test-strings.cc
+++ b/deps/v8/test/cctest/test-strings.cc
@@ -40,6 +40,58 @@
 #include "cctest.h"
 #include "zone-inl.h"
 
+// Adapted from http://en.wikipedia.org/wiki/Multiply-with-carry
+class RandomNumberGenerator {
+ public:
+  RandomNumberGenerator() {
+    init();
+  }
+
+  void init(uint32_t seed = 0x5688c73e) {
+    static const uint32_t phi = 0x9e3779b9;
+    c = 362436;
+    i = kQSize-1;
+    Q[0] = seed;
+    Q[1] = seed + phi;
+    Q[2] = seed + phi + phi;
+    for (unsigned j = 3; j < kQSize; j++) {
+      Q[j] = Q[j - 3] ^ Q[j - 2] ^ phi ^ j;
+    }
+  }
+
+  uint32_t next() {
+    uint64_t a = 18782;
+    uint32_t r = 0xfffffffe;
+    i = (i + 1) & (kQSize-1);
+    uint64_t t = a * Q[i] + c;
+    c = (t >> 32);
+    uint32_t x = static_cast<uint32_t>(t + c);
+    if (x < c) {
+      x++;
+      c++;
+    }
+    return (Q[i] = r - x);
+  }
+
+  uint32_t next(int max) {
+    return next() % max;
+  }
+
+  bool next(double threshold) {
+    ASSERT(threshold >= 0.0 && threshold <= 1.0);
+    if (threshold == 1.0) return true;
+    if (threshold == 0.0) return false;
+    uint32_t value = next() % 100000;
+    return threshold > static_cast<double>(value)/100000.0;
+  }
+
+ private:
+  static const uint32_t kQSize = 4096;
+  uint32_t Q[kQSize];
+  uint32_t c;
+  uint32_t i;
+};
+
 
 using namespace v8::internal;