Util.h revision 0c40524953f3d36a880f91183302a2ea5c722930 
1/*
2 * Copyright (C) 2016 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 UTIL_H_
18#define UTIL_H_
19
20#include <cstdlib>
21#include <memory>
22
23#include "android-base/macros.h"
24
25namespace android {
26namespace util {
27
28/**
29 * Makes a std::unique_ptr<> with the template parameter inferred by the
30 * compiler.
31 * This will be present in C++14 and can be removed then.
32 */
33template <typename T, class... Args>
34std::unique_ptr<T> make_unique(Args&&... args) {
35  return std::unique_ptr<T>(new T{std::forward<Args>(args)...});
36}
37
38// Based on std::unique_ptr, but uses free() to release malloc'ed memory
39// without incurring the size increase of holding on to a custom deleter.
40template <typename T>
41class unique_cptr {
42 public:
43  using pointer = typename std::add_pointer<T>::type;
44
45  constexpr unique_cptr() : ptr_(nullptr) {}
46  constexpr unique_cptr(std::nullptr_t) : ptr_(nullptr) {}
47  explicit unique_cptr(pointer ptr) : ptr_(ptr) {}
48  unique_cptr(unique_cptr&& o) : ptr_(o.ptr_) { o.ptr_ = nullptr; }
49
50  ~unique_cptr() { std::free(reinterpret_cast<void*>(ptr_)); }
51
52  inline unique_cptr& operator=(unique_cptr&& o) {
53    if (&o == this) {
54      return *this;
55    }
56
57    std::free(reinterpret_cast<void*>(ptr_));
58    ptr_ = o.ptr_;
59    o.ptr_ = nullptr;
60    return *this;
61  }
62
63  inline unique_cptr& operator=(std::nullptr_t) {
64    std::free(reinterpret_cast<void*>(ptr_));
65    ptr_ = nullptr;
66    return *this;
67  }
68
69  pointer release() {
70    pointer result = ptr_;
71    ptr_ = nullptr;
72    return result;
73  }
74
75  inline pointer get() const { return ptr_; }
76
77  void reset(pointer ptr = pointer()) {
78    if (ptr == ptr_) {
79      return;
80    }
81
82    pointer old_ptr = ptr_;
83    ptr_ = ptr;
84    std::free(reinterpret_cast<void*>(old_ptr));
85  }
86
87  inline void swap(unique_cptr& o) { std::swap(ptr_, o.ptr_); }
88
89  inline explicit operator bool() const { return ptr_ != nullptr; }
90
91  inline typename std::add_lvalue_reference<T>::type operator*() const { return *ptr_; }
92
93  inline pointer operator->() const { return ptr_; }
94
95  inline bool operator==(const unique_cptr& o) const { return ptr_ == o.ptr_; }
96
97  inline bool operator!=(const unique_cptr& o) const { return ptr_ != o.ptr_; }
98
99  inline bool operator==(std::nullptr_t) const { return ptr_ == nullptr; }
100
101  inline bool operator!=(std::nullptr_t) const { return ptr_ != nullptr; }
102
103 private:
104  DISALLOW_COPY_AND_ASSIGN(unique_cptr);
105
106  pointer ptr_;
107};
108
109inline uint32_t fix_package_id(uint32_t resid, uint8_t package_id) {
110  return resid | (static_cast<uint32_t>(package_id) << 24);
111}
112
113inline uint8_t get_package_id(uint32_t resid) {
114  return static_cast<uint8_t>((resid >> 24) & 0x000000ffu);
115}
116
117// The type ID is 1-based, so if the returned value is 0 it is invalid.
118inline uint8_t get_type_id(uint32_t resid) {
119  return static_cast<uint8_t>((resid >> 16) & 0x000000ffu);
120}
121
122inline uint16_t get_entry_id(uint32_t resid) { return static_cast<uint16_t>(resid & 0x0000ffffu); }
123
124inline bool is_internal_resid(uint32_t resid) {
125  return (resid & 0xffff0000u) != 0 && (resid & 0x00ff0000u) == 0;
126}
127
128inline bool is_valid_resid(uint32_t resid) {
129  return (resid & 0x00ff0000u) != 0 && (resid & 0xff000000u) != 0;
130}
131
132void ReadUtf16StringFromDevice(const uint16_t* src, size_t len, std::string* out);
133
134}  // namespace util
135}  // namespace android
136
137#endif /* UTIL_H_ */
138