Utils.h revision c1d7b7f71ce1a55548d7e8bb32d728190e2ffd47 
1/*
2 * Copyright (C) 2006 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#ifndef _ANDROID_GRAPHICS_UTILS_H_
18#define _ANDROID_GRAPHICS_UTILS_H_
19
20#include "SkStream.h"
21
22#include "android_util_Binder.h"
23
24#include <jni.h>
25#include <androidfw/Asset.h>
26
27namespace android {
28
29class AssetStreamAdaptor : public SkStreamRewindable {
30public:
31    AssetStreamAdaptor(Asset*);
32
33    virtual bool rewind();
34    virtual size_t read(void* buffer, size_t size);
35    virtual bool hasLength() const { return true; }
36    virtual size_t getLength() const;
37    virtual bool isAtEnd() const;
38
39    virtual SkStreamRewindable* duplicate() const;
40private:
41    Asset* fAsset;
42};
43
44/**
45 *  Make a deep copy of the asset, and return it as a stream, or NULL if there
46 *  was an error.
47 *  FIXME: If we could "ref/reopen" the asset, we may not need to copy it here.
48 */
49
50SkMemoryStream* CopyAssetToStream(Asset*);
51
52/** Restore the file descriptor's offset in our destructor
53 */
54class AutoFDSeek {
55public:
56    AutoFDSeek(int fd) : fFD(fd) {
57        fCurr = ::lseek(fd, 0, SEEK_CUR);
58    }
59    ~AutoFDSeek() {
60        if (fCurr >= 0) {
61            ::lseek(fFD, fCurr, SEEK_SET);
62        }
63    }
64private:
65    int     fFD;
66    off64_t   fCurr;
67};
68
69jobject nullObjectReturn(const char msg[]);
70
71/** Check if the file descriptor is seekable.
72 */
73bool isSeekable(int descriptor);
74
75}; // namespace android
76
77#endif  // _ANDROID_GRAPHICS_UTILS_H_
78