Stephen Hines | b53c8a5 | 2013-04-05 22:17:36 -0700 | [diff] [blame] | 1 | /* |
| 2 | * Copyright 2011, 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 | #if !defined(SERIALIZE_H) |
| 18 | #define SERIALIZE_H |
| 19 | |
| 20 | #include "traits.h" |
| 21 | |
| 22 | #include <algorithm> |
| 23 | #include <vector> |
| 24 | |
| 25 | #include "utils/rsl_assert.h" |
| 26 | #include <string.h> |
| 27 | #include <stdint.h> |
| 28 | #include <stddef.h> |
| 29 | |
| 30 | namespace detail { |
| 31 | inline bool is_host_little_endian() { |
| 32 | unsigned long one = 0x1UL; |
| 33 | return *reinterpret_cast<unsigned char *>(&one); |
| 34 | } |
| 35 | |
| 36 | inline void swap_byte_order(unsigned char (&array)[1]) { |
| 37 | // Nothing to do |
| 38 | } |
| 39 | |
| 40 | inline void swap_byte_order(unsigned char (&array)[2]) { |
| 41 | std::swap(array[0], array[1]); |
| 42 | } |
| 43 | |
| 44 | inline void swap_byte_order(unsigned char (&array)[4]) { |
| 45 | std::swap(array[0], array[3]); |
| 46 | std::swap(array[1], array[2]); |
| 47 | } |
| 48 | |
| 49 | inline void swap_byte_order(unsigned char (&array)[8]) { |
| 50 | std::swap(array[0], array[7]); |
| 51 | std::swap(array[1], array[6]); |
| 52 | std::swap(array[2], array[5]); |
| 53 | std::swap(array[3], array[4]); |
| 54 | } |
| 55 | } |
| 56 | |
| 57 | |
| 58 | template <bool isArchiveLittleEndian> |
| 59 | class ArchiveReader { |
| 60 | private: |
| 61 | unsigned char const *buf_begin; |
| 62 | unsigned char const *buf_end; |
| 63 | unsigned char const *cursor; |
| 64 | unsigned char const *cursor_base; |
| 65 | |
| 66 | bool good; |
| 67 | |
| 68 | public: |
| 69 | ArchiveReader(unsigned char const *buf = NULL, size_t size = 0) |
| 70 | : buf_begin(buf), buf_end(buf + size), |
| 71 | cursor(buf), cursor_base(NULL), good(buf != NULL) { |
| 72 | } |
| 73 | |
| 74 | void prologue(size_t size) { |
| 75 | rsl_assert(cursor_base == NULL); |
| 76 | cursor_base = cursor; |
| 77 | } |
| 78 | |
| 79 | void epilogue(size_t size) { |
| 80 | rsl_assert(cursor_base != NULL); |
| 81 | rsl_assert(cursor_base + size >= cursor); |
| 82 | cursor = cursor_base + size; |
| 83 | cursor_base = NULL; |
| 84 | } |
| 85 | |
| 86 | void seek(off_t off, bool from_begin = false) { |
| 87 | if (from_begin) { |
| 88 | cursor = buf_begin + off; |
| 89 | } else { |
| 90 | cursor += off; |
| 91 | } |
| 92 | } |
| 93 | |
| 94 | void readBytes(void *array, size_t size) { |
| 95 | if (!good || cursor + size > buf_end) { |
| 96 | good = false; |
| 97 | } else { |
| 98 | memcpy(array, cursor, size); |
| 99 | } |
| 100 | } |
| 101 | |
| 102 | template <size_t size> |
| 103 | void operator&(char (&array)[size]) { |
| 104 | readBytes(array, size); |
| 105 | seek(size); |
| 106 | } |
| 107 | |
| 108 | template <size_t size> |
| 109 | void operator&(unsigned char (&array)[size]) { |
| 110 | readBytes(array, size); |
| 111 | seek(size); |
| 112 | } |
| 113 | |
| 114 | template <typename T> |
| 115 | void operator&(T &v) { |
| 116 | seekAlignment<T>(); |
| 117 | readBytes(&v, TypeTraits<T>::size); |
| 118 | seek(TypeTraits<T>::size); |
| 119 | |
| 120 | if (isArchiveLittleEndian != detail::is_host_little_endian()) { |
| 121 | detail::swap_byte_order( |
| 122 | reinterpret_cast<unsigned char (&)[TypeTraits<T>::size]>(v)); |
| 123 | } |
| 124 | } |
| 125 | |
| 126 | operator void const *() const { |
| 127 | return good ? this : 0; |
| 128 | } |
| 129 | |
| 130 | bool operator!() const { |
| 131 | return !good; |
| 132 | } |
| 133 | |
| 134 | private: |
| 135 | template <typename T> |
| 136 | void seekAlignment() { |
| 137 | size_t align = TypeTraits<T>::align; |
| 138 | size_t delta = static_cast<size_t>(cursor - buf_begin) % align; |
| 139 | |
| 140 | if (delta > 0) { |
| 141 | seek(align - delta); |
| 142 | } |
| 143 | } |
| 144 | |
| 145 | }; |
| 146 | |
| 147 | typedef ArchiveReader<true> ArchiveReaderLE; |
| 148 | typedef ArchiveReader<false> ArchiveReaderBE; |
| 149 | |
| 150 | #endif // SERIALIZE_H |