1 files changed, 104 insertions, 0 deletions
diff --git a/src/gcinfo/arraylist.cpp b/src/gcinfo/arraylist.cpp
new file mode 100644
index 0000000000..566304c7ac
--- /dev/null
+++ b/src/gcinfo/arraylist.cpp
@@ -0,0 +1,104 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+// See the LICENSE file in the project root for more information.
+
+#include <stdint.h>
+#include <windows.h>
+#include "debugmacros.h"
+#include "iallocator.h"
+#include "gcinfoarraylist.h"
+#include "safemath.h"
+
+inline size_t roundUp(size_t size, size_t alignment)
+{
+    // `alignment` must be a power of two
+    assert(alignment != 0);
+    assert((alignment & (alignment - 1)) == 0);
+
+    return (size + (alignment - 1)) & ~(alignment - 1);
+}
+
+GcInfoArrayListBase::GcInfoArrayListBase(IAllocator* allocator)
+    : m_allocator(allocator),
+      m_firstChunk(nullptr),
+      m_lastChunk(nullptr),
+      m_lastChunkCount(0),
+      m_lastChunkCapacity(0),
+      m_itemCount(0)
+{
+    assert(m_allocator != nullptr);
+}
+
+GcInfoArrayListBase::~GcInfoArrayListBase()
+{
+    for (ChunkBase* list = m_firstChunk, *chunk; list != nullptr; list = chunk)
+    {
+        chunk = list->m_next;
+        m_allocator->Free(list);
+    }
+}
+
+void GcInfoArrayListBase::AppendNewChunk(size_t firstChunkCapacity, size_t elementSize, size_t chunkAlignment)
+{
+    size_t chunkCapacity = (m_firstChunk == nullptr) ? firstChunkCapacity : (m_lastChunkCapacity * GrowthFactor);
+
+    S_SIZE_T chunkSize = S_SIZE_T(roundUp(sizeof(ChunkBase), chunkAlignment)) + (S_SIZE_T(elementSize) * S_SIZE_T(chunkCapacity));
+    assert(!chunkSize.IsOverflow());
+
+    ChunkBase* chunk = reinterpret_cast<ChunkBase*>(m_allocator->Alloc(chunkSize.Value()));
+    chunk->m_next = nullptr;
+
+    if (m_lastChunk != nullptr)
+    {
+        assert(m_firstChunk != nullptr);
+        m_lastChunk->m_next = chunk;
+    }
+    else
+    {
+        assert(m_lastChunk == nullptr);
+        m_firstChunk = chunk;
+    }
+
+    m_lastChunk = chunk;
+    m_lastChunkCount = 0;
+    m_lastChunkCapacity = chunkCapacity;
+}
+
+GcInfoArrayListBase::IteratorBase::IteratorBase(GcInfoArrayListBase* list, size_t firstChunkCapacity)
+    : m_list(list)
+{
+    assert(m_list != nullptr);
+
+    // Note: if the list is empty, m_list->firstChunk == nullptr == m_list->lastChunk and m_lastChunkCount == 0.
+    //       In that case, the next two lines will set m_currentChunk to nullptr and m_currentChunkCount to 0.
+    m_currentChunk = m_list->m_firstChunk;
+    m_currentChunkCount = (m_currentChunk == m_list->m_lastChunk) ? m_list->m_lastChunkCount : firstChunkCapacity;
+}
+
+GcInfoArrayListBase::ChunkBase* GcInfoArrayListBase::IteratorBase::GetNextChunk(size_t& elementCount)
+{
+    if (m_currentChunk == nullptr)
+    {
+        elementCount = 0;
+        return nullptr;
+    }
+
+    ChunkBase* chunk = m_currentChunk;
+    elementCount = m_currentChunkCount;
+
+    m_currentChunk = m_currentChunk->m_next;
+    if (m_currentChunk == nullptr)
+    {
+        m_currentChunkCount = 0;
+    }
+    else if (m_currentChunk == m_list->m_lastChunk)
+    {
+        m_currentChunkCount = m_list->m_lastChunkCount;
+    }
+    else
+    {
+        m_currentChunkCount *= GrowthFactor;
+    }
+
+    return chunk;
+}