1 files changed, 78 insertions, 0 deletions
diff --git a/source/core/slang-random-generator.cpp b/source/core/slang-random-generator.cpp
index ce43067aa..ec06336f1 100644
--- a/source/core/slang-random-generator.cpp
+++ b/source/core/slang-random-generator.cpp
@@ -71,6 +71,57 @@ int64_t RandomGenerator::nextInt64InRange(int64_t min, int64_t max)
     return (nextPositiveInt64() % diff) + min;
 }
 
+static uint8_t* _nextData(RandomGenerator* rand, uint8_t* out, size_t size)
+{
+    if (size)
+    {
+        SLANG_ASSERT(size <= 4);
+        uint32_t v = uint32_t(rand->nextInt32());
+        uint8_t* dst = (uint8_t*)out;
+        for (size_t i = 0; i < size; ++i)
+        {
+            dst[i] = uint8_t(v);
+            v >>= 8;
+        }
+    }
+    return out + size;
+}
+
+void RandomGenerator::nextData(void* out, size_t size)
+{
+    uint8_t* dst = (uint8_t*)out;
+    uint8_t*const end = dst + size;
+
+    // For short runs just output
+    if (size <= 4)
+    {
+        _nextData(this, dst, size);
+        return;
+    }
+    
+    {
+        const size_t preAlign = size_t(((size_t(dst) + 3) & ~size_t(3)) - size_t(dst));
+        dst = _nextData(this, dst, preAlign);
+    }
+
+    // Check invariants
+    SLANG_ASSERT((size_t(dst) & 3) == 0 && end >= dst);
+
+    {
+        const size_t middleCount = size_t(end - dst) >> 2;
+        if (middleCount)
+        {
+            nextInt32s((int32_t*)dst, middleCount);
+            dst += middleCount * sizeof(int32_t);
+        }
+    }
+
+    // Check invariants
+    SLANG_ASSERT((size_t(dst) & 3) == 0 && end >= dst);
+
+    _nextData(this, dst, size_t(end - dst));
+}
+
 /* static */RandomGenerator* RandomGenerator::create(int32_t seed)
 {
     return new DefaultRandomGenerator(seed);
@@ -155,7 +206,34 @@ int32_t Mt19937RandomGenerator::nextInt32()
     return int32_t(y);
 }
 
+void Mt19937RandomGenerator::nextInt32s(int32_t* dst, size_t count)
+{
+    while (count)
+    {
+        if (m_index >= kNumEntries)
+        {
+            _generate();
+        }
+
+        const size_t remaining = kNumEntries - m_index;
+        const size_t run = (count < remaining) ? count : remaining;
+
+        const uint32_t* src = m_mt + m_index;
+        for (size_t i = 0; i < run; i++)
+        {
+            uint32_t y = src[i];
+            y = y ^ (y >> 11);
+            y = y ^ ((y << 7) & uint32_t(0x9d2c5680u));
+            y = y ^ ((y << 15) & uint32_t(0xefc6000u));
+            y = y ^ (y >> 18);
 
+            dst[i] = int32_t(y);
+        }
 
+        m_index += int(run);
+        dst += run;
+        count -= run;
+    }
+}
 
 } // namespace Slang