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// Copyright (c) 2011 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/win/enum_variant.h"
#include <algorithm>
#include "base/logging.h"
namespace base {
namespace win {
EnumVariant::EnumVariant(unsigned long count)
: items_(new VARIANT[count]),
count_(count),
current_index_(0) {
}
EnumVariant::~EnumVariant() {
}
VARIANT* EnumVariant::ItemAt(unsigned long index) {
DCHECK(index < count_);
return &items_[index];
}
ULONG STDMETHODCALLTYPE EnumVariant::AddRef() {
return IUnknownImpl::AddRef();
}
ULONG STDMETHODCALLTYPE EnumVariant::Release() {
return IUnknownImpl::Release();
}
STDMETHODIMP EnumVariant::QueryInterface(REFIID riid, void** ppv) {
if (riid == IID_IEnumVARIANT) {
*ppv = static_cast<IEnumVARIANT*>(this);
AddRef();
return S_OK;
}
return IUnknownImpl::QueryInterface(riid, ppv);
}
STDMETHODIMP EnumVariant::Next(ULONG requested_count,
VARIANT* out_elements,
ULONG* out_elements_received) {
unsigned long count = std::min(requested_count, count_ - current_index_);
for (unsigned long i = 0; i < count; ++i)
out_elements[i] = items_[current_index_ + i];
current_index_ += count;
*out_elements_received = count;
return (count == requested_count ? S_OK : S_FALSE);
}
STDMETHODIMP EnumVariant::Skip(ULONG skip_count) {
unsigned long count = skip_count;
if (current_index_ + count > count_)
count = count_ - current_index_;
current_index_ += count;
return (count == skip_count ? S_OK : S_FALSE);
}
STDMETHODIMP EnumVariant::Reset() {
current_index_ = 0;
return S_OK;
}
STDMETHODIMP EnumVariant::Clone(IEnumVARIANT** out_cloned_object) {
EnumVariant* other = new EnumVariant(count_);
if (count_ > 0)
memcpy(other->ItemAt(0), &items_[0], count_ * sizeof(VARIANT));
other->Skip(current_index_);
other->AddRef();
*out_cloned_object = other;
return S_OK;
}
} // namespace win
} // namespace base
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