1 //===- Endian.h - Utilities for IO with endian specific data ----*- C++ -*-===//
3 // The LLVM Compiler Infrastructure
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
8 //===----------------------------------------------------------------------===//
10 // This file declares generic functions to read and write endian specific data.
12 //===----------------------------------------------------------------------===//
14 #ifndef LLVM_SUPPORT_ENDIAN_H
15 #define LLVM_SUPPORT_ENDIAN_H
17 #include "llvm/Support/AlignOf.h"
18 #include "llvm/Support/Host.h"
19 #include "llvm/Support/SwapByteOrder.h"
23 enum endianness {big, little, native};
25 // These are named values for common alignments.
26 enum {aligned = 0, unaligned = 1};
29 /// \brief ::value is either alignment, or alignof(T) if alignment is 0.
30 template<class T, int alignment>
31 struct PickAlignment {
32 enum {value = alignment == 0 ? AlignOf<T>::Alignment : alignment};
34 } // end namespace detail
37 /// Swap the bytes of value to match the given endianness.
38 template<typename value_type, endianness endian>
39 inline value_type byte_swap(value_type value) {
40 if (endian != native && sys::IsBigEndianHost != (endian == big))
41 return sys::SwapByteOrder(value);
45 /// Read a value of a particular endianness from memory.
46 template<typename value_type,
48 std::size_t alignment>
49 inline value_type read(const void *memory) {
53 LLVM_ASSUME_ALIGNED(memory,
54 (detail::PickAlignment<value_type, alignment>::value)),
56 return byte_swap<value_type, endian>(ret);
59 /// Write a value to memory with a particular endianness.
60 template<typename value_type,
62 std::size_t alignment>
63 inline void write(void *memory, value_type value) {
64 value = byte_swap<value_type, endian>(value);
65 memcpy(LLVM_ASSUME_ALIGNED(memory,
66 (detail::PickAlignment<value_type, alignment>::value)),
70 } // end namespace endian
73 template<typename value_type,
75 std::size_t alignment>
76 struct packed_endian_specific_integral {
77 operator value_type() const {
78 return endian::read<value_type, endian, alignment>(
79 (const void*)Value.buffer);
82 void operator=(value_type newValue) {
83 endian::write<value_type, endian, alignment>(
84 (void*)Value.buffer, newValue);
88 AlignedCharArray<PickAlignment<value_type, alignment>::value,
89 sizeof(value_type)> Value;
91 } // end namespace detail
93 typedef detail::packed_endian_specific_integral
94 <uint8_t, little, unaligned> ulittle8_t;
95 typedef detail::packed_endian_specific_integral
96 <uint16_t, little, unaligned> ulittle16_t;
97 typedef detail::packed_endian_specific_integral
98 <uint32_t, little, unaligned> ulittle32_t;
99 typedef detail::packed_endian_specific_integral
100 <uint64_t, little, unaligned> ulittle64_t;
102 typedef detail::packed_endian_specific_integral
103 <int8_t, little, unaligned> little8_t;
104 typedef detail::packed_endian_specific_integral
105 <int16_t, little, unaligned> little16_t;
106 typedef detail::packed_endian_specific_integral
107 <int32_t, little, unaligned> little32_t;
108 typedef detail::packed_endian_specific_integral
109 <int64_t, little, unaligned> little64_t;
111 typedef detail::packed_endian_specific_integral
112 <uint8_t, little, aligned> aligned_ulittle8_t;
113 typedef detail::packed_endian_specific_integral
114 <uint16_t, little, aligned> aligned_ulittle16_t;
115 typedef detail::packed_endian_specific_integral
116 <uint32_t, little, aligned> aligned_ulittle32_t;
117 typedef detail::packed_endian_specific_integral
118 <uint64_t, little, aligned> aligned_ulittle64_t;
120 typedef detail::packed_endian_specific_integral
121 <int8_t, little, aligned> aligned_little8_t;
122 typedef detail::packed_endian_specific_integral
123 <int16_t, little, aligned> aligned_little16_t;
124 typedef detail::packed_endian_specific_integral
125 <int32_t, little, aligned> aligned_little32_t;
126 typedef detail::packed_endian_specific_integral
127 <int64_t, little, aligned> aligned_little64_t;
129 typedef detail::packed_endian_specific_integral
130 <uint8_t, big, unaligned> ubig8_t;
131 typedef detail::packed_endian_specific_integral
132 <uint16_t, big, unaligned> ubig16_t;
133 typedef detail::packed_endian_specific_integral
134 <uint32_t, big, unaligned> ubig32_t;
135 typedef detail::packed_endian_specific_integral
136 <uint64_t, big, unaligned> ubig64_t;
138 typedef detail::packed_endian_specific_integral
139 <int8_t, big, unaligned> big8_t;
140 typedef detail::packed_endian_specific_integral
141 <int16_t, big, unaligned> big16_t;
142 typedef detail::packed_endian_specific_integral
143 <int32_t, big, unaligned> big32_t;
144 typedef detail::packed_endian_specific_integral
145 <int64_t, big, unaligned> big64_t;
147 typedef detail::packed_endian_specific_integral
148 <uint8_t, big, aligned> aligned_ubig8_t;
149 typedef detail::packed_endian_specific_integral
150 <uint16_t, big, aligned> aligned_ubig16_t;
151 typedef detail::packed_endian_specific_integral
152 <uint32_t, big, aligned> aligned_ubig32_t;
153 typedef detail::packed_endian_specific_integral
154 <uint64_t, big, aligned> aligned_ubig64_t;
156 typedef detail::packed_endian_specific_integral
157 <int8_t, big, aligned> aligned_big8_t;
158 typedef detail::packed_endian_specific_integral
159 <int16_t, big, aligned> aligned_big16_t;
160 typedef detail::packed_endian_specific_integral
161 <int32_t, big, aligned> aligned_big32_t;
162 typedef detail::packed_endian_specific_integral
163 <int64_t, big, aligned> aligned_big64_t;
165 typedef detail::packed_endian_specific_integral
166 <uint16_t, native, unaligned> unaligned_uint16_t;
167 typedef detail::packed_endian_specific_integral
168 <uint32_t, native, unaligned> unaligned_uint32_t;
169 typedef detail::packed_endian_specific_integral
170 <uint64_t, native, unaligned> unaligned_uint64_t;
172 typedef detail::packed_endian_specific_integral
173 <int16_t, native, unaligned> unaligned_int16_t;
174 typedef detail::packed_endian_specific_integral
175 <int32_t, native, unaligned> unaligned_int32_t;
176 typedef detail::packed_endian_specific_integral
177 <int64_t, native, unaligned> unaligned_int64_t;
178 } // end namespace llvm
179 } // end namespace support