LLVM  8.0.0svn
SwapByteOrder.h
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1 //===- SwapByteOrder.h - Generic and optimized byte swaps -------*- 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 and optimized functions to swap the byte order of
11 // an integral type.
12 //
13 //===----------------------------------------------------------------------===//
14 
15 #ifndef LLVM_SUPPORT_SWAPBYTEORDER_H
16 #define LLVM_SUPPORT_SWAPBYTEORDER_H
17 
18 #include "llvm/Support/Compiler.h"
19 #include "llvm/Support/DataTypes.h"
20 #include <cstddef>
21 #if defined(_MSC_VER) && !defined(_DEBUG)
22 #include <stdlib.h>
23 #endif
24 
25 namespace llvm {
26 namespace sys {
27 
28 /// SwapByteOrder_16 - This function returns a byte-swapped representation of
29 /// the 16-bit argument.
30 inline uint16_t SwapByteOrder_16(uint16_t value) {
31 #if defined(_MSC_VER) && !defined(_DEBUG)
32  // The DLL version of the runtime lacks these functions (bug!?), but in a
33  // release build they're replaced with BSWAP instructions anyway.
34  return _byteswap_ushort(value);
35 #else
36  uint16_t Hi = value << 8;
37  uint16_t Lo = value >> 8;
38  return Hi | Lo;
39 #endif
40 }
41 
42 /// SwapByteOrder_32 - This function returns a byte-swapped representation of
43 /// the 32-bit argument.
45 #if defined(__llvm__) || (LLVM_GNUC_PREREQ(4, 3, 0) && !defined(__ICC))
46  return __builtin_bswap32(value);
47 #elif defined(_MSC_VER) && !defined(_DEBUG)
48  return _byteswap_ulong(value);
49 #else
50  uint32_t Byte0 = value & 0x000000FF;
51  uint32_t Byte1 = value & 0x0000FF00;
52  uint32_t Byte2 = value & 0x00FF0000;
53  uint32_t Byte3 = value & 0xFF000000;
54  return (Byte0 << 24) | (Byte1 << 8) | (Byte2 >> 8) | (Byte3 >> 24);
55 #endif
56 }
57 
58 /// SwapByteOrder_64 - This function returns a byte-swapped representation of
59 /// the 64-bit argument.
60 inline uint64_t SwapByteOrder_64(uint64_t value) {
61 #if defined(__llvm__) || (LLVM_GNUC_PREREQ(4, 3, 0) && !defined(__ICC))
62  return __builtin_bswap64(value);
63 #elif defined(_MSC_VER) && !defined(_DEBUG)
64  return _byteswap_uint64(value);
65 #else
66  uint64_t Hi = SwapByteOrder_32(uint32_t(value));
67  uint32_t Lo = SwapByteOrder_32(uint32_t(value >> 32));
68  return (Hi << 32) | Lo;
69 #endif
70 }
71 
72 inline unsigned char getSwappedBytes(unsigned char C) { return C; }
73 inline signed char getSwappedBytes(signed char C) { return C; }
74 inline char getSwappedBytes(char C) { return C; }
75 
76 inline unsigned short getSwappedBytes(unsigned short C) { return SwapByteOrder_16(C); }
77 inline signed short getSwappedBytes( signed short C) { return SwapByteOrder_16(C); }
78 
79 inline unsigned int getSwappedBytes(unsigned int C) { return SwapByteOrder_32(C); }
80 inline signed int getSwappedBytes( signed int C) { return SwapByteOrder_32(C); }
81 
82 #if __LONG_MAX__ == __INT_MAX__
83 inline unsigned long getSwappedBytes(unsigned long C) { return SwapByteOrder_32(C); }
84 inline signed long getSwappedBytes( signed long C) { return SwapByteOrder_32(C); }
85 #elif __LONG_MAX__ == __LONG_LONG_MAX__
86 inline unsigned long getSwappedBytes(unsigned long C) { return SwapByteOrder_64(C); }
87 inline signed long getSwappedBytes( signed long C) { return SwapByteOrder_64(C); }
88 #else
89 #error "Unknown long size!"
90 #endif
91 
92 inline unsigned long long getSwappedBytes(unsigned long long C) {
93  return SwapByteOrder_64(C);
94 }
95 inline signed long long getSwappedBytes(signed long long C) {
96  return SwapByteOrder_64(C);
97 }
98 
99 inline float getSwappedBytes(float C) {
100  union {
101  uint32_t i;
102  float f;
103  } in, out;
104  in.f = C;
105  out.i = SwapByteOrder_32(in.i);
106  return out.f;
107 }
108 
109 inline double getSwappedBytes(double C) {
110  union {
111  uint64_t i;
112  double d;
113  } in, out;
114  in.d = C;
115  out.i = SwapByteOrder_64(in.i);
116  return out.d;
117 }
118 
119 template<typename T>
120 inline void swapByteOrder(T &Value) {
121  Value = getSwappedBytes(Value);
122 }
123 
124 } // end namespace sys
125 } // end namespace llvm
126 
127 #endif
uint64_t CallInst * C
void swapByteOrder(T &Value)
Compute iterated dominance frontiers using a linear time algorithm.
Definition: AllocatorList.h:24
uint32_t SwapByteOrder_32(uint32_t value)
SwapByteOrder_32 - This function returns a byte-swapped representation of the 32-bit argument...
Definition: SwapByteOrder.h:44
uint16_t SwapByteOrder_16(uint16_t value)
SwapByteOrder_16 - This function returns a byte-swapped representation of the 16-bit argument...
Definition: SwapByteOrder.h:30
uint64_t SwapByteOrder_64(uint64_t value)
SwapByteOrder_64 - This function returns a byte-swapped representation of the 64-bit argument...
Definition: SwapByteOrder.h:60
unsigned char getSwappedBytes(unsigned char C)
Definition: SwapByteOrder.h:72
LLVM Value Representation.
Definition: Value.h:73