Rework swapping code.

3 files changed, 426 insertions, 252 deletions

diff --git a/elfcpp/elfcpp.h b/elfcpp/elfcpp.h
index 3ae005ddc0..d92b46d382 100644
--- a/elfcpp/elfcpp.h
+++ b/elfcpp/elfcpp.h
@@ -6,6 +6,7 @@
 #define ELFCPP_H
 
 #include "elfcpp_config.h"
+#include "elfcpp_swap.h"
 
 #include <stdint.h>
 
@@ -559,24 +560,6 @@ struct Elf_sizes
   static const int rela_size = sizeof(internal::Rela_data<size>);
 };
 
-// Given the address of an Elf_Word, return the value.
-
-template<bool big_endian>
-inline Elf_Word
-read_elf_word(const Elf_Word* p)
-{
-  return internal::convert_word<big_endian>(*p);
-}
-
-// Store an Elf_Word into an address.
-
-template<bool big_endian>
-inline void
-write_elf_word(Elf_Word* p, Elf_Word v)
-{
-  *p = internal::convert_word<big_endian>(v);
-}
-
 // Accessor class for the ELF file header.
 
 template<int size, bool big_endian>
@@ -593,55 +576,55 @@ class Ehdr
 
   Elf_Half
   get_e_type() const
-  { return internal::convert_half<big_endian>(this->p_->e_type); }
+  { return Convert<16, big_endian>::convert_host(this->p_->e_type); }
 
   Elf_Half
   get_e_machine() const
-  { return internal::convert_half<big_endian>(this->p_->e_machine); }
+  { return Convert<16, big_endian>::convert_host(this->p_->e_machine); }
 
   Elf_Word
   get_e_version() const
-  { return internal::convert_word<big_endian>(this->p_->e_version); }
+  { return Convert<32, big_endian>::convert_host(this->p_->e_version); }
 
   typename Elf_types<size>::Elf_Addr
   get_e_entry() const
-  { return internal::convert_addr<size, big_endian>(this->p_->e_entry); }
+  { return Convert<size, big_endian>::convert_host(this->p_->e_entry); }
 
   typename Elf_types<size>::Elf_Off
   get_e_phoff() const
-  { return internal::convert_off<size, big_endian>(this->p_->e_phoff); }
+  { return Convert<size, big_endian>::convert_host(this->p_->e_phoff); }
 
   typename Elf_types<size>::Elf_Off
   get_e_shoff() const
-  { return internal::convert_off<size, big_endian>(this->p_->e_shoff); }
+  { return Convert<size, big_endian>::convert_host(this->p_->e_shoff); }
 
   Elf_Word
   get_e_flags() const
-  { return internal::convert_word<big_endian>(this->p_->e_flags); }
+  { return Convert<32, big_endian>::convert_host(this->p_->e_flags); }
 
   Elf_Half
   get_e_ehsize() const
-  { return internal::convert_half<big_endian>(this->p_->e_ehsize); }
+  { return Convert<16, big_endian>::convert_host(this->p_->e_ehsize); }
 
   Elf_Half
   get_e_phentsize() const
-  { return internal::convert_half<big_endian>(this->p_->e_phentsize); }
+  { return Convert<16, big_endian>::convert_host(this->p_->e_phentsize); }
 
   Elf_Half
   get_e_phnum() const
-  { return internal::convert_half<big_endian>(this->p_->e_phnum); }
+  { return Convert<16, big_endian>::convert_host(this->p_->e_phnum); }
 
   Elf_Half
   get_e_shentsize() const
-  { return internal::convert_half<big_endian>(this->p_->e_shentsize); }
+  { return Convert<16, big_endian>::convert_host(this->p_->e_shentsize); }
 
   Elf_Half
   get_e_shnum() const
-  { return internal::convert_half<big_endian>(this->p_->e_shnum); }
+  { return Convert<16, big_endian>::convert_host(this->p_->e_shnum); }
 
   Elf_Half
   get_e_shstrndx() const
-  { return internal::convert_half<big_endian>(this->p_->e_shstrndx); }
+  { return Convert<16, big_endian>::convert_host(this->p_->e_shstrndx); }
 
  private:
   const internal::Ehdr_data<size>* p_;
@@ -663,55 +646,55 @@ class Ehdr_write
 
   void
   put_e_type(Elf_Half v)
-  { this->p_->e_type = internal::convert_half<big_endian>(v); }
+  { this->p_->e_type = Convert<16, big_endian>::convert_host(v); }
   
   void
   put_e_machine(Elf_Half v)
-  { this->p_->e_machine = internal::convert_half<big_endian>(v); }
+  { this->p_->e_machine = Convert<16, big_endian>::convert_host(v); }
 
   void
   put_e_version(Elf_Word v)
-  { this->p_->e_version = internal::convert_word<big_endian>(v); }
+  { this->p_->e_version = Convert<32, big_endian>::convert_host(v); }
 
   void
   put_e_entry(typename Elf_types<size>::Elf_Addr v)
-  { this->p_->e_entry = internal::convert_addr<size, big_endian>(v); }
+  { this->p_->e_entry = Convert<size, big_endian>::convert_host(v); }
 
   void
   put_e_phoff(typename Elf_types<size>::Elf_Off v)
-  { this->p_->e_phoff = internal::convert_off<size, big_endian>(v); }
+  { this->p_->e_phoff = Convert<size, big_endian>::convert_host(v); }
 
   void
   put_e_shoff(typename Elf_types<size>::Elf_Off v)
-  { this->p_->e_shoff = internal::convert_off<size, big_endian>(v); }
+  { this->p_->e_shoff = Convert<size, big_endian>::convert_host(v); }
 
   void
   put_e_flags(Elf_Word v)
-  { this->p_->e_flags = internal::convert_word<big_endian>(v); }
+  { this->p_->e_flags = Convert<32, big_endian>::convert_host(v); }
 
   void
   put_e_ehsize(Elf_Half v)
-  { this->p_->e_ehsize = internal::convert_half<big_endian>(v); }
+  { this->p_->e_ehsize = Convert<16, big_endian>::convert_host(v); }
 
   void
   put_e_phentsize(Elf_Half v)
-  { this->p_->e_phentsize = internal::convert_half<big_endian>(v); }
+  { this->p_->e_phentsize = Convert<16, big_endian>::convert_host(v); }
 
   void
   put_e_phnum(Elf_Half v)
-  { this->p_->e_phnum = internal::convert_half<big_endian>(v); }
+  { this->p_->e_phnum = Convert<16, big_endian>::convert_host(v); }
 
   void
   put_e_shentsize(Elf_Half v)
-  { this->p_->e_shentsize = internal::convert_half<big_endian>(v); }
+  { this->p_->e_shentsize = Convert<16, big_endian>::convert_host(v); }
 
   void
   put_e_shnum(Elf_Half v)
-  { this->p_->e_shnum = internal::convert_half<big_endian>(v); }
+  { this->p_->e_shnum = Convert<16, big_endian>::convert_host(v); }
 
   void
   put_e_shstrndx(Elf_Half v)
-  { this->p_->e_shstrndx = internal::convert_half<big_endian>(v); }
+  { this->p_->e_shstrndx = Convert<16, big_endian>::convert_host(v); }
 
  private:
   internal::Ehdr_data<size>* p_;
@@ -729,44 +712,44 @@ class Shdr
 
   Elf_Word
   get_sh_name() const
-  { return internal::convert_word<big_endian>(this->p_->sh_name); }
+  { return Convert<32, big_endian>::convert_host(this->p_->sh_name); }
 
   Elf_Word
   get_sh_type() const
-  { return internal::convert_word<big_endian>(this->p_->sh_type); }
+  { return Convert<32, big_endian>::convert_host(this->p_->sh_type); }
 
   typename Elf_types<size>::Elf_WXword
   get_sh_flags() const
-  { return internal::convert_wxword<size, big_endian>(this->p_->sh_flags); }
+  { return Convert<size, big_endian>::convert_host(this->p_->sh_flags); }
 
   typename Elf_types<size>::Elf_Addr
   get_sh_addr() const
-  { return internal::convert_addr<size, big_endian>(this->p_->sh_addr); }
+  { return Convert<size, big_endian>::convert_host(this->p_->sh_addr); }
 
   typename Elf_types<size>::Elf_Off
   get_sh_offset() const
-  { return internal::convert_off<size, big_endian>(this->p_->sh_offset); }
+  { return Convert<size, big_endian>::convert_host(this->p_->sh_offset); }
 
   typename Elf_types<size>::Elf_WXword
   get_sh_size() const
-  { return internal::convert_wxword<size, big_endian>(this->p_->sh_size); }
+  { return Convert<size, big_endian>::convert_host(this->p_->sh_size); }
 
   Elf_Word
   get_sh_link() const
-  { return internal::convert_word<big_endian>(this->p_->sh_link); }
+  { return Convert<32, big_endian>::convert_host(this->p_->sh_link); }
 
   Elf_Word
   get_sh_info() const
-  { return internal::convert_word<big_endian>(this->p_->sh_info); }
+  { return Convert<32, big_endian>::convert_host(this->p_->sh_info); }
 
   typename Elf_types<size>::Elf_WXword
   get_sh_addralign() const
   { return
-      internal::convert_wxword<size, big_endian>(this->p_->sh_addralign); }
+      Convert<size, big_endian>::convert_host(this->p_->sh_addralign); }
 
   typename Elf_types<size>::Elf_WXword
   get_sh_entsize() const
-  { return internal::convert_wxword<size, big_endian>(this->p_->sh_entsize); }
+  { return Convert<size, big_endian>::convert_host(this->p_->sh_entsize); }
 
  private:
   const internal::Shdr_data<size>* p_;
@@ -784,43 +767,43 @@ class Shdr_write
 
   void
   put_sh_name(Elf_Word v)
-  { this->p_->sh_name = internal::convert_word<big_endian>(v); }
+  { this->p_->sh_name = Convert<32, big_endian>::convert_host(v); }
 
   void
   put_sh_type(Elf_Word v)
-  { this->p_->sh_type = internal::convert_word<big_endian>(v); }
+  { this->p_->sh_type = Convert<32, big_endian>::convert_host(v); }
 
   void
   put_sh_flags(typename Elf_types<size>::Elf_WXword v)
-  { this->p_->sh_flags = internal::convert_wxword<size, big_endian>(v); }
+  { this->p_->sh_flags = Convert<size, big_endian>::convert_host(v); }
 
   void
   put_sh_addr(typename Elf_types<size>::Elf_Addr v)
-  { this->p_->sh_addr = internal::convert_addr<size, big_endian>(v); }
+  { this->p_->sh_addr = Convert<size, big_endian>::convert_host(v); }
 
   void
   put_sh_offset(typename Elf_types<size>::Elf_Off v)
-  { this->p_->sh_offset = internal::convert_off<size, big_endian>(v); }
+  { this->p_->sh_offset = Convert<size, big_endian>::convert_host(v); }
 
   void
   put_sh_size(typename Elf_types<size>::Elf_WXword v)
-  { this->p_->sh_size = internal::convert_wxword<size, big_endian>(v); }
+  { this->p_->sh_size = Convert<size, big_endian>::convert_host(v); }
 
   void
   put_sh_link(Elf_Word v)
-  { this->p_->sh_link = internal::convert_word<big_endian>(v); }
+  { this->p_->sh_link = Convert<32, big_endian>::convert_host(v); }
 
   void
   put_sh_info(Elf_Word v)
-  { this->p_->sh_info = internal::convert_word<big_endian>(v); }
+  { this->p_->sh_info = Convert<32, big_endian>::convert_host(v); }
 
   void
   put_sh_addralign(typename Elf_types<size>::Elf_WXword v)
-  { this->p_->sh_addralign = internal::convert_wxword<size, big_endian>(v); }
+  { this->p_->sh_addralign = Convert<size, big_endian>::convert_host(v); }
 
   void
   put_sh_entsize(typename Elf_types<size>::Elf_WXword v)
-  { this->p_->sh_entsize = internal::convert_wxword<size, big_endian>(v); }
+  { this->p_->sh_entsize = Convert<size, big_endian>::convert_host(v); }
 
  private:
   internal::Shdr_data<size>* p_;
@@ -838,35 +821,35 @@ class Phdr
 
   Elf_Word
   get_p_type() const
-  { return internal::convert_word<big_endian>(this->p_->p_type); }
+  { return Convert<32, big_endian>::convert_host(this->p_->p_type); }
 
   typename Elf_types<size>::Elf_Off
   get_p_offset() const
-  { return internal::convert_off<size, big_endian>(this->p_->p_offset); }
+  { return Convert<size, big_endian>::convert_host(this->p_->p_offset); }
 
   typename Elf_types<size>::Elf_Addr
   get_p_vaddr() const
-  { return internal::convert_addr<size, big_endian>(this->p_->p_vaddr); }
+  { return Convert<size, big_endian>::convert_host(this->p_->p_vaddr); }
 
   typename Elf_types<size>::Elf_Addr
   get_p_paddr() const
-  { return internal::convert_addr<size, big_endian>(this->p_->p_paddr); }
+  { return Convert<size, big_endian>::convert_host(this->p_->p_paddr); }
 
   typename Elf_types<size>::Elf_WXword
   get_p_filesz() const
-  { return internal::convert_wxword<size, big_endian>(this->p_->p_filesz); }
+  { return Convert<size, big_endian>::convert_host(this->p_->p_filesz); }
 
   typename Elf_types<size>::Elf_WXword
   get_p_memsz() const
-  { return internal::convert_wxword<size, big_endian>(this->p_->p_memsz); }
+  { return Convert<size, big_endian>::convert_host(this->p_->p_memsz); }
 
   Elf_Word
   get_p_flags() const
-  { return internal::convert_word<big_endian>(this->p_->p_flags); }
+  { return Convert<32, big_endian>::convert_host(this->p_->p_flags); }
 
   typename Elf_types<size>::Elf_WXword
   get_p_align() const
-  { return internal::convert_wxword<size, big_endian>(this->p_->p_align); }
+  { return Convert<size, big_endian>::convert_host(this->p_->p_align); }
 
  private:
   const internal::Phdr_data<size>* p_;
@@ -884,35 +867,35 @@ class Phdr_write
 
   void
   put_p_type(Elf_Word v)
-  { this->p_->p_type = internal::convert_word<big_endian>(v); }
+  { this->p_->p_type = Convert<32, big_endian>::convert_host(v); }
 
   void
   put_p_offset(typename Elf_types<size>::Elf_Off v)
-  { this->p_->p_offset = internal::convert_off<size, big_endian>(v); }
+  { this->p_->p_offset = Convert<size, big_endian>::convert_host(v); }
 
   void
   put_p_vaddr(typename Elf_types<size>::Elf_Addr v)
-  { this->p_->p_vaddr = internal::convert_addr<size, big_endian>(v); }
+  { this->p_->p_vaddr = Convert<size, big_endian>::convert_host(v); }
 
   void
   put_p_paddr(typename Elf_types<size>::Elf_Addr v)
-  { this->p_->p_paddr = internal::convert_addr<size, big_endian>(v); }
+  { this->p_->p_paddr = Convert<size, big_endian>::convert_host(v); }
 
   void
   put_p_filesz(typename Elf_types<size>::Elf_WXword v)
-  { this->p_->p_filesz = internal::convert_wxword<size, big_endian>(v); }
+  { this->p_->p_filesz = Convert<size, big_endian>::convert_host(v); }
 
   void
   put_p_memsz(typename Elf_types<size>::Elf_WXword v)
-  { this->p_->p_memsz = internal::convert_wxword<size, big_endian>(v); }
+  { this->p_->p_memsz = Convert<size, big_endian>::convert_host(v); }
 
   void
   put_p_flags(Elf_Word v)
-  { this->p_->p_flags = internal::convert_word<big_endian>(v); }
+  { this->p_->p_flags = Convert<32, big_endian>::convert_host(v); }
 
   void
   put_p_align(typename Elf_types<size>::Elf_WXword v)
-  { this->p_->p_align = internal::convert_wxword<size, big_endian>(v); }
+  { this->p_->p_align = Convert<size, big_endian>::convert_host(v); }
 
  private:
   internal::Phdr_data<size>* p_;
@@ -930,15 +913,15 @@ class Sym
 
   Elf_Word
   get_st_name() const
-  { return internal::convert_word<big_endian>(this->p_->st_name); }
+  { return Convert<32, big_endian>::convert_host(this->p_->st_name); }
 
   typename Elf_types<size>::Elf_Addr
   get_st_value() const
-  { return internal::convert_addr<size, big_endian>(this->p_->st_value); }
+  { return Convert<size, big_endian>::convert_host(this->p_->st_value); }
 
   typename Elf_types<size>::Elf_WXword
   get_st_size() const
-  { return internal::convert_wxword<size, big_endian>(this->p_->st_size); }
+  { return Convert<size, big_endian>::convert_host(this->p_->st_size); }
 
   unsigned char
   get_st_info() const
@@ -966,7 +949,7 @@ class Sym
 
   Elf_Half
   get_st_shndx() const
-  { return internal::convert_half<big_endian>(this->p_->st_shndx); }
+  { return Convert<16, big_endian>::convert_host(this->p_->st_shndx); }
 
  private:
   const internal::Sym_data<size>* p_;
@@ -984,15 +967,15 @@ class Sym_write
 
   void
   put_st_name(Elf_Word v)
-  { this->p_->st_name = internal::convert_word<big_endian>(v); }
+  { this->p_->st_name = Convert<32, big_endian>::convert_host(v); }
 
   void
   put_st_value(typename Elf_types<size>::Elf_Addr v)
-  { this->p_->st_value = internal::convert_addr<size, big_endian>(v); }
+  { this->p_->st_value = Convert<size, big_endian>::convert_host(v); }
 
   void
   put_st_size(typename Elf_types<size>::Elf_WXword v)
-  { this->p_->st_size = internal::convert_wxword<size, big_endian>(v); }
+  { this->p_->st_size = Convert<size, big_endian>::convert_host(v); }
 
   void
   put_st_info(unsigned char v)
@@ -1012,7 +995,7 @@ class Sym_write
 
   void
   put_st_shndx(Elf_Half v)
-  { this->p_->st_shndx = internal::convert_half<big_endian>(v); }
+  { this->p_->st_shndx = Convert<16, big_endian>::convert_host(v); }
 
   Sym<size, big_endian>
   sym()
@@ -1034,11 +1017,11 @@ class Rel
 
   typename Elf_types<size>::Elf_Addr
   get_r_offset() const
-  { return internal::convert_addr<size, big_endian>(this->p_->r_offset); }
+  { return Convert<size, big_endian>::convert_host(this->p_->r_offset); }
 
   typename Elf_types<size>::Elf_WXword
   get_r_info() const
-  { return internal::convert_wxword<size, big_endian>(this->p_->r_info); }
+  { return Convert<size, big_endian>::convert_host(this->p_->r_info); }
 
  private:
   const internal::Rel_data<size>* p_;
@@ -1054,15 +1037,15 @@ class Rela
 
   typename Elf_types<size>::Elf_Addr
   get_r_offset() const
-  { return internal::convert_addr<size, big_endian>(this->p_->r_offset); }
+  { return Convert<size, big_endian>::convert_host(this->p_->r_offset); }
 
   typename Elf_types<size>::Elf_WXword
   get_r_info() const
-  { return internal::convert_wxword<size, big_endian>(this->p_->r_info); }
+  { return Convert<size, big_endian>::convert_host(this->p_->r_info); }
 
   typename Elf_types<size>::Elf_Swxword
   get_r_addend() const
-  { return internal::convert_swxword<size, big_endian>(this->p_->r_addend); }
+  { return Convert<size, big_endian>::convert_host(this->p_->r_addend); }
 
  private:
   const internal::Rela_data<size>* p_;
diff --git a/elfcpp/elfcpp_internal.h b/elfcpp/elfcpp_internal.h
index e4c863644a..c991535cb0 100644
--- a/elfcpp/elfcpp_internal.h
+++ b/elfcpp/elfcpp_internal.h
@@ -5,8 +5,6 @@
 
 #include "elfcpp_config.h"
 
-#include <byteswap.h>
-
 #ifndef ELFCPP_INTERNAL_H
 #define ELFCPP_INTERNAL_H
 
@@ -16,163 +14,6 @@ namespace elfcpp
 namespace internal
 {
 
-#ifdef WORDS_BIGENDIAN
-const bool host_big_endian = true;
-#else
-const bool host_big_endian = false;
-#endif
-
-// Conversion routines between target and host.
-
-// Convert Elf_Half.
-
-template<bool same_endian>
-Elf_Half
-convert_half_host(Elf_Half v);
-
-template<>
-inline Elf_Half
-convert_half_host<true>(Elf_Half v)
-{
-  return v;
-}
-
-template<>
-inline Elf_Half
-convert_half_host<false>(Elf_Half v)
-{
-  return bswap_16(v);
-}
-
-template<bool big_endian>
-inline Elf_Half
-convert_half(Elf_Half v)
-{
-  return convert_half_host<big_endian == host_big_endian>(v);
-}
-
-// Convert Elf_Word.
-
-template<bool same_endian>
-Elf_Word
-convert_word_host(Elf_Word v);
-
-template<>
-inline Elf_Word
-convert_word_host<true>(Elf_Word v)
-{
-  return v;
-}
-
-template<>
-inline Elf_Word
-convert_word_host<false>(Elf_Word v)
-{
-  return bswap_32(v);
-}
-
-template<bool big_endian>
-inline Elf_Word
-convert_word(Elf_Word v)
-{
-  return convert_word_host<big_endian == host_big_endian>(v);
-}
-
-// Convert Elf_Xword.
-
-template<bool same_endian>
-Elf_Xword
-convert_xword_host(Elf_Xword v);
-
-template<>
-inline Elf_Xword
-convert_xword_host<true>(Elf_Xword v)
-{
-  return v;
-}
-
-template<>
-inline Elf_Xword
-convert_xword_host<false>(Elf_Xword v)
-{
-  return bswap_64(v);
-}
-
-template<bool big_endian>
-inline Elf_Xword
-convert_xword(Elf_Xword v)
-{
-  return convert_xword_host<big_endian == host_big_endian>(v);
-}
-
-// Convert Elf_addr.
-
-template<int size, bool same_endian>
-typename Elf_types<size>::Elf_Addr
-convert_addr_size(typename Elf_types<size>::Elf_Addr);
-
-template<>
-inline Elf_types<32>::Elf_Addr
-convert_addr_size<32, true>(Elf_types<32>::Elf_Addr v)
-{
-  return v;
-}
-
-template<>
-inline Elf_types<64>::Elf_Addr
-convert_addr_size<64, true>(Elf_types<64>::Elf_Addr v)
-{
-  return v;
-}
-
-template<>
-inline Elf_types<32>::Elf_Addr
-convert_addr_size<32, false>(Elf_types<32>::Elf_Addr v)
-{
-  return bswap_32(v);
-}
-
-template<>
-inline Elf_types<64>::Elf_Addr
-convert_addr_size<64, false>(Elf_types<64>::Elf_Addr v)
-{
-  return bswap_64(v);
-}
-
-template<int size, bool big_endian>
-inline typename Elf_types<size>::Elf_Addr
-convert_addr(typename Elf_types<size>::Elf_Addr v)
-{
-  return convert_addr_size<size, big_endian == host_big_endian>(v);
-}
-
-// Convert Elf_Off.
-
-template<int size, bool big_endian>
-inline typename Elf_types<size>::Elf_Off
-convert_off(typename Elf_types<size>::Elf_Off v)
-{
-  return convert_addr_size<size, big_endian == host_big_endian>(v);
-}
-
-// Convert Elf_WXword.
-
-template<int size, bool big_endian>
-inline typename Elf_types<size>::Elf_WXword
-convert_wxword(typename Elf_types<size>::Elf_WXword v)
-{
-  return convert_addr_size<size, big_endian == host_big_endian>(v);
-}
-
-// Convert ELF_Swxword.
-
-template<int size, bool big_endian>
-inline typename Elf_types<size>::Elf_Swxword
-convert_swxword(typename Elf_types<size>::Elf_Swxword v)
-{
-  return convert_addr_size<size, big_endian == host_big_endian>(v);
-}
-
 // The ELF file header.
 
 template<int size>
diff --git a/elfcpp/elfcpp_swap.h b/elfcpp/elfcpp_swap.h
new file mode 100644
index 0000000000..979108e9e0
--- /dev/null
+++ b/elfcpp/elfcpp_swap.h
@@ -0,0 +1,350 @@
+// elfcpp_swap.h -- Handle swapping for elfcpp   -*- C++ -*-
+
+// This header file defines basic template classes to efficiently swap
+// numbers between host form and target form.  When the host and
+// target have the same endianness, these turn into no-ops.
+
+#ifndef ELFCPP_SWAP_H
+#define ELFCPP_SWAP_H
+
+#include <stdint.h>
+#include <endian.h>
+#include <byteswap.h>
+
+namespace elfcpp
+{
+
+// Endian simply indicates whether the host is big endian or not.
+
+struct Endian
+{
+ public:
+  // Used for template specializations.
+  static const bool host_big_endian = __BYTE_ORDER == __BIG_ENDIAN;
+};
+
+// Valtype_base is a template based on size (8, 16, 32, 64) which
+// defines the type Valtype as the unsigned integer of the specified
+// size.
+
+template<int size>
+struct Valtype_base;
+
+template<>
+struct Valtype_base<8>
+{
+  typedef unsigned char Valtype;
+};
+
+template<>
+struct Valtype_base<16>
+{
+  typedef uint16_t Valtype;
+};
+
+template<>
+struct Valtype_base<32>
+{
+  typedef uint32_t Valtype;
+};
+
+template<>
+struct Valtype_base<64>
+{
+  typedef uint64_t Valtype;
+};
+
+// Convert_endian is a template based on size and on whether the host
+// and target have the same endianness.  It defines the type Valtype
+// as Valtype_base does, and also defines a function convert_host
+// which takes an argument of type Valtype and returns the same value,
+// but swapped if the host and target have different endianness.
+
+template<int size, bool same_endian>
+struct Convert_endian;
+
+template<int size>
+struct Convert_endian<size, true>
+{
+  typedef typename Valtype_base<size>::Valtype Valtype;
+
+  static inline Valtype
+  convert_host(Valtype v)
+  { return v; }
+};
+
+template<>
+struct Convert_endian<8, false>
+{
+  typedef Valtype_base<8>::Valtype Valtype;
+
+  static inline Valtype
+  convert_host(Valtype v)
+  { return v; }
+};
+
+template<>
+struct Convert_endian<16, false>
+{
+  typedef Valtype_base<16>::Valtype Valtype;
+
+  static inline Valtype
+  convert_host(Valtype v)
+  { return bswap_16(v); }
+};
+
+template<>
+struct Convert_endian<32, false>
+{
+  typedef Valtype_base<32>::Valtype Valtype;
+
+  static inline Valtype
+  convert_host(Valtype v)
+  { return bswap_32(v); }
+};
+
+template<>
+struct Convert_endian<64, false>
+{
+  typedef Valtype_base<64>::Valtype Valtype;
+
+  static inline Valtype
+  convert_host(Valtype v)
+  { return bswap_64(v); }
+};
+
+// Convert is a template based on size and on whether the target is
+// big endian.  It defines Valtype and convert_host like
+// Convert_endian.  That is, it is just like Convert_endian except in
+// the meaning of the second template parameter.
+
+template<int size, bool big_endian>
+struct Convert
+{
+  typedef typename Valtype_base<size>::Valtype Valtype;
+
+  static inline Valtype
+  convert_host(Valtype v)
+  {
+    return Convert_endian<size, big_endian == Endian::host_big_endian>
+      ::convert_host(v);
+  }
+};
+
+// Swap is a template based on size and on whether the target is big
+// endian.  It defines the type Valtype and the functions readval and
+// writeval.  The functions read and write values of the appropriate
+// size out of buffers, swapping them if necessary.  readval and
+// writeval are overloaded to take pointers to the appropriate type or
+// pointers to unsigned char.
+
+template<int size, bool big_endian>
+struct Swap
+{
+  typedef typename Valtype_base<size>::Valtype Valtype;
+
+  static inline Valtype
+  readval(const Valtype* wv)
+  { return Convert<size, big_endian>::convert_host(*wv); }
+
+  static inline void
+  writeval(Valtype* wv, Valtype v)
+  { *wv = Convert<size, big_endian>::convert_host(v); }
+
+  static inline Valtype
+  readval(const unsigned char* wv)
+  { return readval(reinterpret_cast<const Valtype*>(wv)); }
+
+  static inline void
+  writeval(unsigned char* wv, Valtype v)
+  { writeval(reinterpret_cast<Valtype*>(wv), v); }
+};
+
+// We need to specialize the 8-bit version of Swap to avoid
+// conflicting overloads, since both versions of readval and writeval
+// will have the same type parameters.
+
+template<bool big_endian>
+struct Swap<8, big_endian>
+{
+  typedef typename Valtype_base<8>::Valtype Valtype;
+
+  static inline Valtype
+  readval(const Valtype* wv)
+  { return *wv; }
+
+  static inline void
+  writeval(Valtype* wv, Valtype v)
+  { *wv = v; }
+};
+
+// Swap_unaligned is a template based on size and on whether the
+// target is big endian.  It defines the type Valtype and the
+// functions readval_unaligned and writeval_unaligned.  The functions
+// read and write values of the appropriate size out of buffers which
+// may be misaligned.
+
+template<int size, bool big_endian>
+struct Swap_unaligned;
+
+template<bool big_endian>
+struct Swap_unaligned<8, big_endian>
+{
+  typedef typename Valtype_base<8>::Valtype Valtype;
+
+  static inline Valtype
+  readval_unaligned(const unsigned char* wv)
+  { return *wv; }
+
+  static inline void
+  writeval_unaligned(unsigned char* wv, Valtype v)
+  { *wv = v; }
+};
+
+template<>
+struct Swap_unaligned<16, false>
+{
+  typedef Valtype_base<16>::Valtype Valtype;
+
+  static inline Valtype
+  readval_unaligned(const unsigned char* wv)
+  {
+    return (wv[1] << 8) | wv[0];
+  }
+
+  static inline void
+  writeval_unaligned(unsigned char* wv, Valtype v)
+  {
+    wv[1] = v >> 8;
+    wv[0] = v;
+  }
+};
+
+template<>
+struct Swap_unaligned<16, true>
+{
+  typedef Valtype_base<16>::Valtype Valtype;
+
+  static inline Valtype
+  readval_unaligned(const unsigned char* wv)
+  {
+    return (wv[0] << 8) | wv[1];
+  }
+
+  static inline void
+  writeval_unaligned(unsigned char* wv, Valtype v)
+  {
+    wv[0] = v >> 8;
+    wv[1] = v;
+  }
+};
+
+template<>
+struct Swap_unaligned<32, false>
+{
+  typedef Valtype_base<32>::Valtype Valtype;
+
+  static inline Valtype
+  readval_unaligned(const unsigned char* wv)
+  {
+    return (wv[3] << 24) | (wv[2] << 16) | (wv[1] << 8) | wv[0];
+  }
+
+  static inline void
+  writeval_unaligned(unsigned char* wv, Valtype v)
+  {
+    wv[3] = v >> 24;
+    wv[2] = v >> 16;
+    wv[1] = v >> 8;
+    wv[0] = v;
+  }
+};
+
+template<>
+struct Swap_unaligned<32, true>
+{
+  typedef Valtype_base<32>::Valtype Valtype;
+
+  static inline Valtype
+  readval_unaligned(const unsigned char* wv)
+  {
+    return (wv[0] << 24) | (wv[1] << 16) | (wv[2] << 8) | wv[3];
+  }
+
+  static inline void
+  writeval_unaligned(unsigned char* wv, Valtype v)
+  {
+    wv[0] = v >> 24;
+    wv[1] = v >> 16;
+    wv[2] = v >> 8;
+    wv[3] = v;
+  }
+};
+
+template<>
+struct Swap_unaligned<64, false>
+{
+  typedef Valtype_base<64>::Valtype Valtype;
+
+  static inline Valtype
+  readval_unaligned(const unsigned char* wv)
+  {
+    return ((static_cast<Valtype>(wv[7]) << 56)
+	    | (static_cast<Valtype>(wv[6]) << 48)
+	    | (static_cast<Valtype>(wv[5]) << 40)
+	    | (static_cast<Valtype>(wv[4]) << 32)
+	    | (static_cast<Valtype>(wv[3]) << 24)
+	    | (static_cast<Valtype>(wv[2]) << 16)
+	    | (static_cast<Valtype>(wv[1]) << 8)
+	    | static_cast<Valtype>(wv[0]));
+  }
+
+  static inline void
+  writeval_unaligned(unsigned char* wv, Valtype v)
+  {
+    wv[7] = v >> 56;
+    wv[6] = v >> 48;
+    wv[5] = v >> 40;
+    wv[4] = v >> 32;
+    wv[3] = v >> 24;
+    wv[2] = v >> 16;
+    wv[1] = v >> 8;
+    wv[0] = v;
+  }
+};
+
+template<>
+struct Swap_unaligned<64, true>
+{
+  typedef Valtype_base<64>::Valtype Valtype;
+
+  static inline Valtype
+  readval_unaligned(const unsigned char* wv)
+  {
+    return ((static_cast<Valtype>(wv[0]) << 56)
+	    | (static_cast<Valtype>(wv[1]) << 48)
+	    | (static_cast<Valtype>(wv[2]) << 40)
+	    | (static_cast<Valtype>(wv[3]) << 32)
+	    | (static_cast<Valtype>(wv[4]) << 24)
+	    | (static_cast<Valtype>(wv[5]) << 16)
+	    | (static_cast<Valtype>(wv[6]) << 8)
+	    | static_cast<Valtype>(wv[7]));
+  }
+
+  static inline void
+  writeval_unaligned(unsigned char* wv, Valtype v)
+  {
+    wv[7] = v >> 56;
+    wv[6] = v >> 48;
+    wv[5] = v >> 40;
+    wv[4] = v >> 32;
+    wv[3] = v >> 24;
+    wv[2] = v >> 16;
+    wv[1] = v >> 8;
+    wv[0] = v;
+  }
+};
+
+} // End namespace elfcpp.
+
+#endif // !defined(ELFCPP_SWAP_H)