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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    15550519 :   uint16_t Hi = value << 8;
      37    15574227 :   uint16_t Lo = value >> 8;
      38    15570091 :   return Hi | Lo;
      39             : #endif
      40             : }
      41             : 
      42             : /// SwapByteOrder_32 - This function returns a byte-swapped representation of
      43             : /// the 32-bit argument.
      44             : inline uint32_t SwapByteOrder_32(uint32_t value) {
      45             : #if defined(__llvm__) || (LLVM_GNUC_PREREQ(4, 3, 0) && !defined(__ICC))
      46     2437464 :   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      222712 :   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          55 : 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        1177 : 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       11534 : 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           0 :   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           0 :   return out.d;
     117             : }
     118             : 
     119             : template<typename T>
     120           0 : inline void swapByteOrder(T &Value) {
     121         555 :   Value = getSwappedBytes(Value);
     122           0 : }
     123           0 : 
     124             : } // end namespace sys
     125           0 : } // end namespace llvm
     126           0 : 
     127             : #endif