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 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 /// Read a value of a particular endianness from a buffer, and increment the
60 /// buffer past that value.
61 template<typename value_type
, endianness endian
, std::size_t alignment
>
62 inline value_type
readNext(const unsigned char *&memory
) {
63 value_type ret
= read
<value_type
, endian
, alignment
>(memory
);
64 memory
+= sizeof(value_type
);
68 /// Write a value to memory with a particular endianness.
69 template<typename value_type
,
71 std::size_t alignment
>
72 inline void write(void *memory
, value_type value
) {
73 value
= byte_swap
<value_type
, endian
>(value
);
74 memcpy(LLVM_ASSUME_ALIGNED(memory
,
75 (detail::PickAlignment
<value_type
, alignment
>::value
)),
79 } // end namespace endian
82 template<typename value_type
,
84 std::size_t alignment
>
85 struct packed_endian_specific_integral
{
86 operator value_type() const {
87 return endian::read
<value_type
, endian
, alignment
>(
88 (const void*)Value
.buffer
);
91 void operator=(value_type newValue
) {
92 endian::write
<value_type
, endian
, alignment
>(
93 (void*)Value
.buffer
, newValue
);
96 packed_endian_specific_integral
&operator+=(value_type newValue
) {
97 *this = *this + newValue
;
101 packed_endian_specific_integral
&operator-=(value_type newValue
) {
102 *this = *this - newValue
;
107 AlignedCharArray
<PickAlignment
<value_type
, alignment
>::value
,
108 sizeof(value_type
)> Value
;
112 explicit ref(void *Ptr
) : Ptr(Ptr
) {}
114 operator value_type() const {
115 return endian::read
<value_type
, endian
, alignment
>(Ptr
);
118 void operator=(value_type NewValue
) {
119 endian::write
<value_type
, endian
, alignment
>(Ptr
, NewValue
);
127 } // end namespace detail
129 typedef detail::packed_endian_specific_integral
130 <uint16_t, little
, unaligned
> ulittle16_t
;
131 typedef detail::packed_endian_specific_integral
132 <uint32_t, little
, unaligned
> ulittle32_t
;
133 typedef detail::packed_endian_specific_integral
134 <uint64_t, little
, unaligned
> ulittle64_t
;
136 typedef detail::packed_endian_specific_integral
137 <int16_t, little
, unaligned
> little16_t
;
138 typedef detail::packed_endian_specific_integral
139 <int32_t, little
, unaligned
> little32_t
;
140 typedef detail::packed_endian_specific_integral
141 <int64_t, little
, unaligned
> little64_t
;
143 typedef detail::packed_endian_specific_integral
144 <uint16_t, little
, aligned
> aligned_ulittle16_t
;
145 typedef detail::packed_endian_specific_integral
146 <uint32_t, little
, aligned
> aligned_ulittle32_t
;
147 typedef detail::packed_endian_specific_integral
148 <uint64_t, little
, aligned
> aligned_ulittle64_t
;
150 typedef detail::packed_endian_specific_integral
151 <int16_t, little
, aligned
> aligned_little16_t
;
152 typedef detail::packed_endian_specific_integral
153 <int32_t, little
, aligned
> aligned_little32_t
;
154 typedef detail::packed_endian_specific_integral
155 <int64_t, little
, aligned
> aligned_little64_t
;
157 typedef detail::packed_endian_specific_integral
158 <uint16_t, big
, unaligned
> ubig16_t
;
159 typedef detail::packed_endian_specific_integral
160 <uint32_t, big
, unaligned
> ubig32_t
;
161 typedef detail::packed_endian_specific_integral
162 <uint64_t, big
, unaligned
> ubig64_t
;
164 typedef detail::packed_endian_specific_integral
165 <int16_t, big
, unaligned
> big16_t
;
166 typedef detail::packed_endian_specific_integral
167 <int32_t, big
, unaligned
> big32_t
;
168 typedef detail::packed_endian_specific_integral
169 <int64_t, big
, unaligned
> big64_t
;
171 typedef detail::packed_endian_specific_integral
172 <uint16_t, big
, aligned
> aligned_ubig16_t
;
173 typedef detail::packed_endian_specific_integral
174 <uint32_t, big
, aligned
> aligned_ubig32_t
;
175 typedef detail::packed_endian_specific_integral
176 <uint64_t, big
, aligned
> aligned_ubig64_t
;
178 typedef detail::packed_endian_specific_integral
179 <int16_t, big
, aligned
> aligned_big16_t
;
180 typedef detail::packed_endian_specific_integral
181 <int32_t, big
, aligned
> aligned_big32_t
;
182 typedef detail::packed_endian_specific_integral
183 <int64_t, big
, aligned
> aligned_big64_t
;
185 typedef detail::packed_endian_specific_integral
186 <uint16_t, native
, unaligned
> unaligned_uint16_t
;
187 typedef detail::packed_endian_specific_integral
188 <uint32_t, native
, unaligned
> unaligned_uint32_t
;
189 typedef detail::packed_endian_specific_integral
190 <uint64_t, native
, unaligned
> unaligned_uint64_t
;
192 typedef detail::packed_endian_specific_integral
193 <int16_t, native
, unaligned
> unaligned_int16_t
;
194 typedef detail::packed_endian_specific_integral
195 <int32_t, native
, unaligned
> unaligned_int32_t
;
196 typedef detail::packed_endian_specific_integral
197 <int64_t, native
, unaligned
> unaligned_int64_t
;
198 } // end namespace llvm
199 } // end namespace support