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)) bytes(bytes_in)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 bytecode_ptr(std::nullptr_t)69 bytecode_ptr(std::nullptr_t) {} 70 get()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 release()91 T *release() { 92 auto *p = ptr.release(); 93 bytes = 0; 94 alignment = 0; 95 return p; 96 } 97 swap(bytecode_ptr & other)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 */ shrink(size_t new_size)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. */ size()119 size_t size() const { return bytes; } 120 121 /** \brief Returns alignment of the memory region in bytes. */ align()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 { operatordeleter130 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