1 | /* |
2 | * Copyright (c) 2017, Intel Corporation |
3 | * |
4 | * Redistribution and use in source and binary forms, with or without |
5 | * modification, are permitted provided that the following conditions are met: |
6 | * |
7 | * * Redistributions of source code must retain the above copyright notice, |
8 | * this list of conditions and the following disclaimer. |
9 | * * Redistributions in binary form must reproduce the above copyright |
10 | * notice, this list of conditions and the following disclaimer in the |
11 | * documentation and/or other materials provided with the distribution. |
12 | * * Neither the name of Intel Corporation nor the names of its contributors |
13 | * may be used to endorse or promote products derived from this software |
14 | * without specific prior written permission. |
15 | * |
16 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS" |
17 | * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE |
18 | * IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE |
19 | * ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR CONTRIBUTORS BE |
20 | * LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR |
21 | * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF |
22 | * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS |
23 | * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN |
24 | * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) |
25 | * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE |
26 | * POSSIBILITY OF SUCH DAMAGE. |
27 | */ |
28 | |
29 | /** |
30 | * \file |
31 | * \brief bytecode_ptr: Smart pointer with unique ownership that knows its |
32 | * length and alignment. |
33 | */ |
34 | |
35 | #ifndef UTIL_BYTECODE_PTR_H |
36 | #define UTIL_BYTECODE_PTR_H |
37 | |
38 | #include "util/alloc.h" |
39 | #include "util/operators.h" |
40 | |
41 | #include <algorithm> // std::max |
42 | #include <cstring> |
43 | #include <memory> |
44 | #include <stdexcept> // std::logic_error |
45 | |
46 | namespace ue2 { |
47 | |
48 | /** |
49 | * \brief Smart pointer that knows its length and alignment and behaves like a |
50 | * std::unique_ptr -- i.e. it retains unique ownership of the memory region. |
51 | * |
52 | * This is intended to be used for flat aligned memory regions that will |
53 | * eventually end up copied into the Hyperscan bytecode. |
54 | */ |
55 | template<typename T> |
56 | class bytecode_ptr : totally_ordered<bytecode_ptr<T>> { |
57 | public: |
58 | bytecode_ptr() = default; |
59 | explicit bytecode_ptr(size_t bytes_in, size_t alignment_in = alignof(T)) |
60 | : bytes(bytes_in), alignment(alignment_in) { |
61 | // posix_memalign doesn't like us asking for smaller alignment. |
62 | size_t mem_align = std::max(alignment, sizeof(void *)); |
63 | ptr.reset(static_cast<T *>(aligned_malloc_internal(bytes, mem_align))); |
64 | if (!ptr) { |
65 | throw std::bad_alloc(); |
66 | } |
67 | } |
68 | |
69 | bytecode_ptr(std::nullptr_t) {} |
70 | |
71 | T *get() const { return ptr.get(); } |
72 | |
73 | T &operator*() { return *ptr; } |
74 | const T &operator*() const { return *ptr; } |
75 | |
76 | T *operator->() { return ptr.get(); } |
77 | const T *operator->() const { return ptr.get(); } |
78 | |
79 | explicit operator bool() const { return ptr != nullptr; } |
80 | |
81 | /** \brief Move converter for shared_ptr. */ |
82 | template <typename ST, class = typename std::enable_if< |
83 | std::is_convertible<T *, ST *>::value>::type> |
84 | operator std::shared_ptr<ST>() && { |
85 | auto d = ptr.get_deleter(); |
86 | return std::shared_ptr<ST>(ptr.release(), d); |
87 | } |
88 | |
89 | void reset(T *p = nullptr) { ptr.reset(p); } |
90 | |
91 | T *release() { |
92 | auto *p = ptr.release(); |
93 | bytes = 0; |
94 | alignment = 0; |
95 | return p; |
96 | } |
97 | |
98 | void swap(bytecode_ptr &other) { |
99 | using std::swap; |
100 | swap(ptr, other.ptr); |
101 | swap(bytes, other.bytes); |
102 | swap(alignment, other.alignment); |
103 | } |
104 | |
105 | /** |
106 | * \brief Reduces the apparent size of the memory region. Note that this |
107 | * does not reallocate and copy, it just changes the value returned by |
108 | * size(). |
109 | */ |
110 | void shrink(size_t new_size) { |
111 | if (new_size > bytes) { |
112 | assert(0); |
113 | throw std::logic_error("Must shrink to a smaller value" ); |
114 | } |
115 | bytes = new_size; |
116 | } |
117 | |
118 | /** \brief Returns size of the memory region in bytes. */ |
119 | size_t size() const { return bytes; } |
120 | |
121 | /** \brief Returns alignment of the memory region in bytes. */ |
122 | size_t align() const { return alignment; } |
123 | |
124 | bool operator==(const bytecode_ptr &a) const { return ptr == a.ptr; } |
125 | bool operator<(const bytecode_ptr &a) const { return ptr < a.ptr; } |
126 | |
127 | private: |
128 | /** \brief Deleter function for std::unique_ptr. */ |
129 | template <typename DT> struct deleter { |
130 | void operator()(DT *p) const { aligned_free_internal(p); } |
131 | }; |
132 | |
133 | std::unique_ptr<T, deleter<T>> ptr; //!< Underlying pointer. |
134 | size_t bytes = 0; //!< Size of memory region in bytes. |
135 | size_t alignment = 0; //!< Alignment of memory region in bytes. |
136 | }; |
137 | |
138 | /** |
139 | * \brief Constructs a bytecode_ptr<T> with the given size and alignment. |
140 | */ |
141 | template<typename T> |
142 | inline bytecode_ptr<T> make_bytecode_ptr(size_t size, |
143 | size_t align = alignof(T)) { |
144 | return bytecode_ptr<T>(size, align); |
145 | } |
146 | |
147 | /** |
148 | * \brief Constructs a bytecode_ptr<T> with the given size and alignment and |
149 | * fills the memory region with zeroes. |
150 | */ |
151 | template<typename T> |
152 | inline bytecode_ptr<T> make_zeroed_bytecode_ptr(size_t size, |
153 | size_t align = alignof(T)) { |
154 | auto ptr = make_bytecode_ptr<T>(size, align); |
155 | std::memset(ptr.get(), 0, size); |
156 | return ptr; |
157 | } |
158 | |
159 | } // namespace ue2 |
160 | |
161 | #endif // UTIL_BYTECODE_PTR_H |
162 | |