1/*
2 * Copyright (C) 2015 The Android Open Source Project
3 *
4 * Licensed under the Apache License, Version 2.0 (the "License");
5 * you may not use this file except in compliance with the License.
6 * You may obtain a copy of the License at
7 *
8 *      http://www.apache.org/licenses/LICENSE-2.0
9 *
10 * Unless required by applicable law or agreed to in writing, software
11 * distributed under the License is distributed on an "AS IS" BASIS,
12 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
13 * See the License for the specific language governing permissions and
14 * limitations under the License.
15 */
16
17#include "ResChunkPullParser.h"
18
19#include <androidfw/ResourceTypes.h>
20#include <cstddef>
21
22namespace aapt {
23
24using android::ResChunk_header;
25
26ResChunkPullParser::Event ResChunkPullParser::next() {
27    if (!isGoodEvent(mEvent)) {
28        return mEvent;
29    }
30
31    if (mEvent == Event::StartDocument) {
32        mCurrentChunk = mData;
33    } else {
34        mCurrentChunk = reinterpret_cast<const ResChunk_header*>(
35                reinterpret_cast<const char*>(mCurrentChunk) + mCurrentChunk->size);
36    }
37
38    const std::ptrdiff_t diff = reinterpret_cast<const char*>(mCurrentChunk)
39            - reinterpret_cast<const char*>(mData);
40    assert(diff >= 0 && "diff is negative");
41    const size_t offset = static_cast<const size_t>(diff);
42
43    if (offset == mLen) {
44        mCurrentChunk = nullptr;
45        return (mEvent = Event::EndDocument);
46    } else if (offset + sizeof(ResChunk_header) > mLen) {
47        mLastError = "chunk is past the end of the document";
48        mCurrentChunk = nullptr;
49        return (mEvent = Event::BadDocument);
50    }
51
52    if (mCurrentChunk->headerSize < sizeof(ResChunk_header)) {
53        mLastError = "chunk has too small header";
54        mCurrentChunk = nullptr;
55        return (mEvent = Event::BadDocument);
56    } else if (mCurrentChunk->size < mCurrentChunk->headerSize) {
57        mLastError = "chunk's total size is smaller than header";
58        mCurrentChunk = nullptr;
59        return (mEvent = Event::BadDocument);
60    } else if (offset + mCurrentChunk->size > mLen) {
61        mLastError = "chunk's data extends past the end of the document";
62        mCurrentChunk = nullptr;
63        return (mEvent = Event::BadDocument);
64    }
65    return (mEvent = Event::Chunk);
66}
67
68} // namespace aapt
69