1 // Copyright (c) 2011 The Chromium Authors. All rights reserved.
2 // Use of this source code is governed by a BSD-style license that can be
3 // found in the LICENSE file.
4
5 #include "base/win/enum_variant.h"
6
7 #include <algorithm>
8
9 #include "base/logging.h"
10
11 namespace base {
12 namespace win {
13
EnumVariant(unsigned long count)14 EnumVariant::EnumVariant(unsigned long count)
15 : items_(new VARIANT[count]),
16 count_(count),
17 current_index_(0) {
18 }
19
~EnumVariant()20 EnumVariant::~EnumVariant() {
21 }
22
ItemAt(unsigned long index)23 VARIANT* EnumVariant::ItemAt(unsigned long index) {
24 DCHECK(index < count_);
25 return &items_[index];
26 }
27
AddRef()28 ULONG STDMETHODCALLTYPE EnumVariant::AddRef() {
29 return IUnknownImpl::AddRef();
30 }
31
Release()32 ULONG STDMETHODCALLTYPE EnumVariant::Release() {
33 return IUnknownImpl::Release();
34 }
35
QueryInterface(REFIID riid,void ** ppv)36 STDMETHODIMP EnumVariant::QueryInterface(REFIID riid, void** ppv) {
37 if (riid == IID_IEnumVARIANT) {
38 *ppv = static_cast<IEnumVARIANT*>(this);
39 AddRef();
40 return S_OK;
41 }
42
43 return IUnknownImpl::QueryInterface(riid, ppv);
44 }
45
Next(ULONG requested_count,VARIANT * out_elements,ULONG * out_elements_received)46 STDMETHODIMP EnumVariant::Next(ULONG requested_count,
47 VARIANT* out_elements,
48 ULONG* out_elements_received) {
49 unsigned long count = std::min(requested_count, count_ - current_index_);
50 for (unsigned long i = 0; i < count; ++i)
51 out_elements[i] = items_[current_index_ + i];
52 current_index_ += count;
53 *out_elements_received = count;
54
55 return (count == requested_count ? S_OK : S_FALSE);
56 }
57
Skip(ULONG skip_count)58 STDMETHODIMP EnumVariant::Skip(ULONG skip_count) {
59 unsigned long count = skip_count;
60 if (current_index_ + count > count_)
61 count = count_ - current_index_;
62
63 current_index_ += count;
64 return (count == skip_count ? S_OK : S_FALSE);
65 }
66
Reset()67 STDMETHODIMP EnumVariant::Reset() {
68 current_index_ = 0;
69 return S_OK;
70 }
71
Clone(IEnumVARIANT ** out_cloned_object)72 STDMETHODIMP EnumVariant::Clone(IEnumVARIANT** out_cloned_object) {
73 EnumVariant* other = new EnumVariant(count_);
74 if (count_ > 0)
75 memcpy(other->ItemAt(0), &items_[0], count_ * sizeof(VARIANT));
76 other->Skip(current_index_);
77 other->AddRef();
78 *out_cloned_object = other;
79 return S_OK;
80 }
81
82 } // namespace win
83 } // namespace base
84