LLVM  3.7.0
Endian.h
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1 //===- Endian.h - Utilities for IO with endian specific data ----*- C++ -*-===//
2 //
3 // The LLVM Compiler Infrastructure
4 //
5 // This file is distributed under the University of Illinois Open Source
6 // License. See LICENSE.TXT for details.
7 //
8 //===----------------------------------------------------------------------===//
9 //
10 // This file declares generic functions to read and write endian specific data.
11 //
12 //===----------------------------------------------------------------------===//
13 
14 #ifndef LLVM_SUPPORT_ENDIAN_H
15 #define LLVM_SUPPORT_ENDIAN_H
16 
17 #include "llvm/Support/AlignOf.h"
18 #include "llvm/Support/Host.h"
20 
21 namespace llvm {
22 namespace support {
24 
25 // These are named values for common alignments.
26 enum {aligned = 0, unaligned = 1};
27 
28 namespace detail {
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};
33  };
34 } // end namespace detail
35 
36 namespace endian {
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);
42  return value;
43 }
44 
45 /// Read a value of a particular endianness from memory.
46 template<typename value_type,
47  endianness endian,
48  std::size_t alignment>
49 inline value_type read(const void *memory) {
50  value_type ret;
51 
52  memcpy(&ret,
53  LLVM_ASSUME_ALIGNED(memory,
55  sizeof(value_type));
56  return byte_swap<value_type, endian>(ret);
57 }
58 
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  typename CharT>
63 inline value_type readNext(const CharT *&memory) {
64  value_type ret = read<value_type, endian, alignment>(memory);
65  memory += sizeof(value_type);
66  return ret;
67 }
68 
69 /// Write a value to memory with a particular endianness.
70 template<typename value_type,
71  endianness endian,
72  std::size_t alignment>
73 inline void write(void *memory, value_type value) {
74  value = byte_swap<value_type, endian>(value);
75  memcpy(LLVM_ASSUME_ALIGNED(memory,
77  &value,
78  sizeof(value_type));
79 }
80 } // end namespace endian
81 
82 namespace detail {
83 template<typename value_type,
84  endianness endian,
85  std::size_t alignment>
87  operator value_type() const {
88  return endian::read<value_type, endian, alignment>(
89  (const void*)Value.buffer);
90  }
91 
92  void operator=(value_type newValue) {
93  endian::write<value_type, endian, alignment>(
94  (void*)Value.buffer, newValue);
95  }
96 
98  *this = *this + newValue;
99  return *this;
100  }
101 
103  *this = *this - newValue;
104  return *this;
105  }
106 
108  *this = *this | newValue;
109  return *this;
110  }
111 
113  *this = *this & newValue;
114  return *this;
115  }
116 
117 private:
119  sizeof(value_type)> Value;
120 
121 public:
122  struct ref {
123  explicit ref(void *Ptr) : Ptr(Ptr) {}
124 
125  operator value_type() const {
126  return endian::read<value_type, endian, alignment>(Ptr);
127  }
128 
129  void operator=(value_type NewValue) {
130  endian::write<value_type, endian, alignment>(Ptr, NewValue);
131  }
132 
133  private:
134  void *Ptr;
135  };
136 };
137 
138 } // end namespace detail
139 
140 typedef detail::packed_endian_specific_integral
146 
153 
160 
167 
169  <uint16_t, big, unaligned> ubig16_t;
171  <uint32_t, big, unaligned> ubig32_t;
173  <uint64_t, big, unaligned> ubig64_t;
174 
176  <int16_t, big, unaligned> big16_t;
178  <int32_t, big, unaligned> big32_t;
180  <int64_t, big, unaligned> big64_t;
181 
188 
195 
202 
209 
210 namespace endian {
211 inline uint16_t read16le(const void *p) { return *(const ulittle16_t *)p; }
212 inline uint32_t read32le(const void *p) { return *(const ulittle32_t *)p; }
213 inline uint64_t read64le(const void *p) { return *(const ulittle64_t *)p; }
214 inline uint16_t read16be(const void *p) { return *(const ubig16_t *)p; }
215 inline uint32_t read32be(const void *p) { return *(const ubig32_t *)p; }
216 inline uint64_t read64be(const void *p) { return *(const ubig64_t *)p; }
217 
218 inline void write16le(void *p, uint16_t v) { *(ulittle16_t *)p = v; }
219 inline void write32le(void *p, uint32_t v) { *(ulittle32_t *)p = v; }
220 inline void write64le(void *p, uint64_t v) { *(ulittle64_t *)p = v; }
221 inline void write16be(void *p, uint16_t v) { *(ubig16_t *)p = v; }
222 inline void write32be(void *p, uint32_t v) { *(ubig32_t *)p = v; }
223 inline void write64be(void *p, uint64_t v) { *(ubig64_t *)p = v; }
224 } // end namespace endian
225 } // end namespace support
226 } // end namespace llvm
227 
228 #endif
detail::packed_endian_specific_integral< uint16_t, native, unaligned > unaligned_uint16_t
Definition: Endian.h:197
packed_endian_specific_integral & operator+=(value_type newValue)
Definition: Endian.h:97
detail::packed_endian_specific_integral< int64_t, native, unaligned > unaligned_int64_t
Definition: Endian.h:208
#define LLVM_ASSUME_ALIGNED(p, a)
LLVM_ASSUME_ALIGNED
Definition: Compiler.h:278
void swapByteOrder(T &Value)
AlignOf - A templated class that contains an enum value representing the alignment of the template ar...
Definition: AlignOf.h:46
value_type read(const void *memory)
Read a value of a particular endianness from memory.
Definition: Endian.h:49
void write64le(void *p, uint64_t v)
Definition: Endian.h:220
detail::packed_endian_specific_integral< uint64_t, big, aligned > aligned_ubig64_t
Definition: Endian.h:187
Helper for building an aligned character array type.
detail::packed_endian_specific_integral< int16_t, little, aligned > aligned_little16_t
Definition: Endian.h:162
detail::packed_endian_specific_integral< uint64_t, big, unaligned > ubig64_t
Definition: Endian.h:173
uint64_t read64be(const void *p)
Definition: Endian.h:216
void write32be(void *p, uint32_t v)
Definition: Endian.h:222
void write16le(void *p, uint16_t v)
Definition: Endian.h:218
detail::packed_endian_specific_integral< uint32_t, big, unaligned > ubig32_t
Definition: Endian.h:171
uint64_t read64le(const void *p)
Definition: Endian.h:213
detail::packed_endian_specific_integral< uint16_t, big, aligned > aligned_ubig16_t
Definition: Endian.h:183
detail::packed_endian_specific_integral< int64_t, little, unaligned > little64_t
Definition: Endian.h:152
detail::packed_endian_specific_integral< int32_t, big, aligned > aligned_big32_t
Definition: Endian.h:192
value_type byte_swap(value_type value)
Swap the bytes of value to match the given endianness.
Definition: Endian.h:39
detail::packed_endian_specific_integral< int16_t, big, aligned > aligned_big16_t
Definition: Endian.h:190
uint32_t read32le(const void *p)
Definition: Endian.h:212
detail::packed_endian_specific_integral< int64_t, little, aligned > aligned_little64_t
Definition: Endian.h:166
uint32_t read32be(const void *p)
Definition: Endian.h:215
detail::packed_endian_specific_integral< int16_t, native, unaligned > unaligned_int16_t
Definition: Endian.h:204
detail::packed_endian_specific_integral< uint32_t, big, aligned > aligned_ubig32_t
Definition: Endian.h:185
void write16be(void *p, uint16_t v)
Definition: Endian.h:221
void write32le(void *p, uint32_t v)
Definition: Endian.h:219
detail::packed_endian_specific_integral< int32_t, little, aligned > aligned_little32_t
Definition: Endian.h:164
packed_endian_specific_integral & operator|=(value_type newValue)
Definition: Endian.h:107
detail::packed_endian_specific_integral< uint32_t, little, aligned > aligned_ulittle32_t
Definition: Endian.h:157
detail::packed_endian_specific_integral< uint64_t, little, aligned > aligned_ulittle64_t
Definition: Endian.h:159
value_type readNext(const CharT *&memory)
Read a value of a particular endianness from a buffer, and increment the buffer past that value...
Definition: Endian.h:63
detail::packed_endian_specific_integral< int32_t, little, unaligned > little32_t
Definition: Endian.h:150
detail::packed_endian_specific_integral< int32_t, big, unaligned > big32_t
Definition: Endian.h:178
packed_endian_specific_integral & operator-=(value_type newValue)
Definition: Endian.h:102
detail::packed_endian_specific_integral< int16_t, little, unaligned > little16_t
Definition: Endian.h:148
packed_endian_specific_integral & operator&=(value_type newValue)
Definition: Endian.h:112
detail::packed_endian_specific_integral< uint64_t, native, unaligned > unaligned_uint64_t
Definition: Endian.h:201
detail::packed_endian_specific_integral< uint16_t, little, unaligned > ulittle16_t
Definition: Endian.h:141
void write(void *memory, value_type value)
Write a value to memory with a particular endianness.
Definition: Endian.h:73
uint16_t read16be(const void *p)
Definition: Endian.h:214
uint16_t read16le(const void *p)
Definition: Endian.h:211
static const bool IsBigEndianHost
Definition: Host.h:35
detail::packed_endian_specific_integral< uint64_t, little, unaligned > ulittle64_t
Definition: Endian.h:145
detail::packed_endian_specific_integral< uint16_t, big, unaligned > ubig16_t
Definition: Endian.h:169
detail::packed_endian_specific_integral< int16_t, big, unaligned > big16_t
Definition: Endian.h:176
detail::packed_endian_specific_integral< int64_t, big, aligned > aligned_big64_t
Definition: Endian.h:194
detail::packed_endian_specific_integral< uint32_t, little, unaligned > ulittle32_t
Definition: Endian.h:143
LLVM Value Representation.
Definition: Value.h:69
detail::packed_endian_specific_integral< int64_t, big, unaligned > big64_t
Definition: Endian.h:180
detail::packed_endian_specific_integral< int32_t, native, unaligned > unaligned_int32_t
Definition: Endian.h:206
detail::packed_endian_specific_integral< uint32_t, native, unaligned > unaligned_uint32_t
Definition: Endian.h:199
::value is either alignment, or alignof(T) if alignment is 0.
Definition: Endian.h:31
detail::packed_endian_specific_integral< uint16_t, little, aligned > aligned_ulittle16_t
Definition: Endian.h:155
void write64be(void *p, uint64_t v)
Definition: Endian.h:223