diff --git a/src/backend/common/Buffer.cpp b/src/backend/common/Buffer.cpp
new file mode 100644
index 0000000..7592b04
--- /dev/null
+++ b/src/backend/common/Buffer.cpp
@@ -0,0 +1,233 @@
+// Copyright 2017 The NXT Authors
+//
+// Licensed under the Apache License, Version 2.0 (the "License");
+// you may not use this file except in compliance with the License.
+// You may obtain a copy of the License at
+//
+//     http://www.apache.org/licenses/LICENSE-2.0
+//
+// Unless required by applicable law or agreed to in writing, software
+// distributed under the License is distributed on an "AS IS" BASIS,
+// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+// See the License for the specific language governing permissions and
+// limitations under the License.
+
+#include "Buffer.h"
+
+#include "Device.h"
+
+#include <utility>
+#include <cstdio>
+
+namespace backend {
+
+    // Buffer
+
+    BufferBase::BufferBase(BufferBuilder* builder)
+        : device(builder->device),
+          size(builder->size),
+          allowedUsage(builder->allowedUsage),
+          currentUsage(builder->currentUsage) {
+    }
+
+    BufferViewBuilder* BufferBase::CreateBufferViewBuilder() {
+        return new BufferViewBuilder(device, this);
+    }
+
+    uint32_t BufferBase::GetSize() const {
+        return size;
+    }
+
+    nxt::BufferUsageBit BufferBase::GetAllowedUsage() const {
+        return allowedUsage;
+    }
+
+    nxt::BufferUsageBit BufferBase::GetUsage() const {
+        return currentUsage;
+    }
+
+    void BufferBase::SetSubData(uint32_t start, uint32_t count, const uint32_t* data) {
+        if ((start + count) * sizeof(uint32_t) > GetSize()) {
+            device->HandleError("Buffer subdata out of range");
+            return;
+        }
+
+        if (!(currentUsage & nxt::BufferUsageBit::Mapped)) {
+            device->HandleError("Buffer needs the mapped usage bit");
+            return;
+        }
+
+        SetSubDataImpl(start, count, data);
+    }
+
+    bool BufferBase::IsFrozen() const {
+        return frozen;
+    }
+
+    bool BufferBase::HasFrozenUsage(nxt::BufferUsageBit usage) const {
+        return frozen && (usage & allowedUsage);
+    }
+
+    bool BufferBase::IsUsagePossible(nxt::BufferUsageBit allowedUsage, nxt::BufferUsageBit usage) {
+        const nxt::BufferUsageBit allReadBits =
+            nxt::BufferUsageBit::TransferSrc |
+            nxt::BufferUsageBit::Index |
+            nxt::BufferUsageBit::Vertex |
+            nxt::BufferUsageBit::Uniform;
+        bool allowed = (usage & allowedUsage) == usage;
+        bool readOnly = (usage & allReadBits) == usage;
+        bool singleUse = nxt::HasZeroOrOneBits(usage);
+        return allowed && (readOnly || singleUse);
+    }
+
+    bool BufferBase::IsTransitionPossible(nxt::BufferUsageBit usage) const {
+        if (frozen) {
+            return false;
+        }
+        return IsUsagePossible(allowedUsage, usage);
+    }
+
+    void BufferBase::TransitionUsageImpl(nxt::BufferUsageBit usage) {
+        assert(IsTransitionPossible(usage));
+        currentUsage = usage;
+    }
+
+    void BufferBase::TransitionUsage(nxt::BufferUsageBit usage) {
+        if (!IsTransitionPossible(usage)) {
+            device->HandleError("Buffer frozen or usage not allowed");
+            return;
+        }
+        TransitionUsageImpl(usage);
+    }
+
+    void BufferBase::FreezeUsage(nxt::BufferUsageBit usage) {
+        if (!IsTransitionPossible(usage)) {
+            device->HandleError("Buffer frozen or usage not allowed");
+            return;
+        }
+        allowedUsage = usage;
+        currentUsage = usage;
+        frozen = true;
+    }
+
+    // BufferBuilder
+
+    enum BufferSetProperties {
+        BUFFER_PROPERTY_ALLOWED_USAGE = 0x1,
+        BUFFER_PROPERTY_INITIAL_USAGE = 0x2,
+        BUFFER_PROPERTY_SIZE = 0x4,
+    };
+
+    BufferBuilder::BufferBuilder(DeviceBase* device) : device(device) {
+    }
+
+    bool BufferBuilder::WasConsumed() const {
+        return consumed;
+    }
+
+    BufferBase* BufferBuilder::GetResult() {
+        constexpr int allProperties = BUFFER_PROPERTY_ALLOWED_USAGE | BUFFER_PROPERTY_SIZE;
+        if ((propertiesSet & allProperties) != allProperties) {
+            device->HandleError("Buffer missing properties");
+            return nullptr;
+        }
+
+        if (!BufferBase::IsUsagePossible(allowedUsage, currentUsage)) {
+            device->HandleError("Initial buffer usage is not allowed");
+            return nullptr;
+        }
+
+        consumed = true;
+        return device->CreateBuffer(this);
+    }
+
+    void BufferBuilder::SetAllowedUsage(nxt::BufferUsageBit usage) {
+        if ((propertiesSet & BUFFER_PROPERTY_ALLOWED_USAGE) != 0) {
+            device->HandleError("Buffer allowedUsage property set multiple times");
+            return;
+        }
+
+        this->allowedUsage = usage;
+        propertiesSet |= BUFFER_PROPERTY_ALLOWED_USAGE;
+    }
+
+    void BufferBuilder::SetInitialUsage(nxt::BufferUsageBit usage) {
+        if ((propertiesSet & BUFFER_PROPERTY_INITIAL_USAGE) != 0) {
+            device->HandleError("Buffer initialUsage property set multiple times");
+            return;
+        }
+
+        this->currentUsage = usage;
+        propertiesSet |= BUFFER_PROPERTY_INITIAL_USAGE;
+    }
+
+    void BufferBuilder::SetSize(uint32_t size) {
+        if ((propertiesSet & BUFFER_PROPERTY_SIZE) != 0) {
+            device->HandleError("Buffer size property set multiple times");
+            return;
+        }
+
+        this->size = size;
+        propertiesSet |= BUFFER_PROPERTY_SIZE;
+    }
+
+    // BufferViewBase
+
+    BufferViewBase::BufferViewBase(BufferViewBuilder* builder)
+        : buffer(std::move(builder->buffer)), size(builder->size), offset(builder->offset) {
+    }
+
+    BufferBase* BufferViewBase::GetBuffer() {
+        return buffer.Get();
+    }
+
+    uint32_t BufferViewBase::GetSize() const {
+        return size;
+    }
+
+    uint32_t BufferViewBase::GetOffset() const {
+        return offset;
+    }
+
+    // BufferViewBuilder
+
+    enum BufferViewSetProperties {
+        BUFFER_VIEW_PROPERTY_EXTENT = 0x1,
+    };
+
+    BufferViewBuilder::BufferViewBuilder(DeviceBase* device, BufferBase* buffer)
+        : device(device), buffer(buffer) {
+    }
+
+    bool BufferViewBuilder::WasConsumed() const {
+        return consumed;
+    }
+
+    BufferViewBase* BufferViewBuilder::GetResult() {
+        constexpr int allProperties = BUFFER_VIEW_PROPERTY_EXTENT;
+        if ((propertiesSet & allProperties) != allProperties) {
+            device->HandleError("Buffer view missing properties");
+            return nullptr;
+        }
+
+        return device->CreateBufferView(this);
+    }
+
+    void BufferViewBuilder::SetExtent(uint32_t offset, uint32_t size) {
+        if ((propertiesSet & BUFFER_VIEW_PROPERTY_EXTENT) != 0) {
+            device->HandleError("Buffer view extent property set multiple times");
+            return;
+        }
+
+        uint64_t viewEnd = static_cast<uint64_t>(offset) + static_cast<uint64_t>(size);
+        if (viewEnd > static_cast<uint64_t>(buffer->GetSize())) {
+            device->HandleError("Buffer view end is OOB");
+            return;
+        }
+
+        this->offset = offset;
+        this->size = size;
+        propertiesSet |= BUFFER_VIEW_PROPERTY_EXTENT;
+    }
+
+}