1 files changed, 101 insertions, 0 deletions
diff --git a/include/llvm/Support/SwapByteOrder.h b/include/llvm/Support/SwapByteOrder.h
new file mode 100644
index 0000000000..6c0592c05a
--- /dev/null
+++ b/include/llvm/Support/SwapByteOrder.h
@@ -0,0 +1,101 @@
+//===- SwapByteOrder.h - Generic and optimized byte swaps -------*- C++ -*-===//
+//
+//                     The LLVM Compiler Infrastructure
+//
+// This file is distributed under the University of Illinois Open Source
+// License. See LICENSE.TXT for details.
+//
+//===----------------------------------------------------------------------===//
+//
+// This file declares generic and optimized functions to swap the byte order of
+// an integral type.
+//
+//===----------------------------------------------------------------------===//
+
+#ifndef LLVM_SYSTEM_SWAP_BYTE_ORDER_H
+#define LLVM_SYSTEM_SWAP_BYTE_ORDER_H
+
+#include "llvm/Support/DataTypes.h"
+#include <cstddef>
+#include <limits>
+
+namespace llvm {
+namespace sys {
+
+/// SwapByteOrder_16 - This function returns a byte-swapped representation of
+/// the 16-bit argument.
+inline uint16_t SwapByteOrder_16(uint16_t value) {
+#if defined(_MSC_VER) && !defined(_DEBUG)
+  // The DLL version of the runtime lacks these functions (bug!?), but in a
+  // release build they're replaced with BSWAP instructions anyway.
+  return _byteswap_ushort(value);
+#else
+  uint16_t Hi = value << 8;
+  uint16_t Lo = value >> 8;
+  return Hi | Lo;
+#endif
+}
+
+/// SwapByteOrder_32 - This function returns a byte-swapped representation of
+/// the 32-bit argument.
+inline uint32_t SwapByteOrder_32(uint32_t value) {
+#if defined(__llvm__) || \
+(__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3)) && !defined(__ICC)
+  return __builtin_bswap32(value);
+#elif defined(_MSC_VER) && !defined(_DEBUG)
+  return _byteswap_ulong(value);
+#else
+  uint32_t Byte0 = value & 0x000000FF;
+  uint32_t Byte1 = value & 0x0000FF00;
+  uint32_t Byte2 = value & 0x00FF0000;
+  uint32_t Byte3 = value & 0xFF000000;
+  return (Byte0 << 24) | (Byte1 << 8) | (Byte2 >> 8) | (Byte3 >> 24);
+#endif
+}
+
+/// SwapByteOrder_64 - This function returns a byte-swapped representation of
+/// the 64-bit argument.
+inline uint64_t SwapByteOrder_64(uint64_t value) {
+#if defined(__llvm__) || \
+(__GNUC__ > 4 || (__GNUC__ == 4 && __GNUC_MINOR__ >= 3)) && !defined(__ICC)
+  return __builtin_bswap64(value);
+#elif defined(_MSC_VER) && !defined(_DEBUG)
+  return _byteswap_uint64(value);
+#else
+  uint64_t Hi = SwapByteOrder_32(uint32_t(value));
+  uint32_t Lo = SwapByteOrder_32(uint32_t(value >> 32));
+  return (Hi << 32) | Lo;
+#endif
+}
+
+inline unsigned char  SwapByteOrder(unsigned char C) { return C; }
+inline   signed char  SwapByteOrder(signed char C) { return C; }
+inline          char  SwapByteOrder(char C) { return C; }
+
+inline unsigned short SwapByteOrder(unsigned short C) { return SwapByteOrder_16(C); }
+inline   signed short SwapByteOrder(  signed short C) { return SwapByteOrder_16(C); }
+
+inline unsigned int   SwapByteOrder(unsigned int   C) { return SwapByteOrder_32(C); }
+inline   signed int   SwapByteOrder(  signed int   C) { return SwapByteOrder_32(C); }
+
+#if __LONG_MAX__ == __INT_MAX__
+inline unsigned long  SwapByteOrder(unsigned long  C) { return SwapByteOrder_32(C); }
+inline   signed long  SwapByteOrder(  signed long  C) { return SwapByteOrder_32(C); }
+#elif __LONG_MAX__ == __LONG_LONG_MAX__
+inline unsigned long  SwapByteOrder(unsigned long  C) { return SwapByteOrder_64(C); }
+inline   signed long  SwapByteOrder(  signed long  C) { return SwapByteOrder_64(C); }
+#else
+#error "Unknown long size!"
+#endif
+
+inline unsigned long long SwapByteOrder(unsigned long long C) {
+  return SwapByteOrder_64(C);
+}
+inline signed long long SwapByteOrder(signed long long C) {
+  return SwapByteOrder_64(C);
+}
+
+} // end namespace sys
+} // end namespace llvm
+
+#endif