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//===- Endian.h - Utilities for IO with endian specific data ----*- 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 functions to read and write endian specific data.
//
//===----------------------------------------------------------------------===//
#ifndef LLVM_SUPPORT_ENDIAN_H
#define LLVM_SUPPORT_ENDIAN_H
#include "llvm/Support/AlignOf.h"
#include "llvm/Support/Host.h"
#include "llvm/Support/SwapByteOrder.h"
namespace llvm {
namespace support {
enum endianness {big, little, native};
// These are named values for common alignments.
enum {aligned = 0, unaligned = 1};
namespace detail {
/// \brief ::value is either alignment, or alignof(T) if alignment is 0.
template<class T, int alignment>
struct PickAlignment {
enum {value = alignment == 0 ? AlignOf<T>::Alignment : alignment};
};
} // end namespace detail
namespace endian {
/// Swap the bytes of value to match the given endianness.
template<typename value_type, endianness endian>
inline value_type byte_swap(value_type value) {
if (endian != native && sys::IsBigEndianHost != (endian == big))
sys::swapByteOrder(value);
return value;
}
/// Read a value of a particular endianness from memory.
template<typename value_type,
endianness endian,
std::size_t alignment>
inline value_type read(const void *memory) {
value_type ret;
memcpy(&ret,
LLVM_ASSUME_ALIGNED(memory,
(detail::PickAlignment<value_type, alignment>::value)),
sizeof(value_type));
return byte_swap<value_type, endian>(ret);
}
/// Read a value of a particular endianness from a buffer, and increment the
/// buffer past that value.
template<typename value_type, endianness endian, std::size_t alignment,
typename CharT>
inline value_type readNext(const CharT *&memory) {
value_type ret = read<value_type, endian, alignment>(memory);
memory += sizeof(value_type);
return ret;
}
/// Write a value to memory with a particular endianness.
template<typename value_type,
endianness endian,
std::size_t alignment>
inline void write(void *memory, value_type value) {
value = byte_swap<value_type, endian>(value);
memcpy(LLVM_ASSUME_ALIGNED(memory,
(detail::PickAlignment<value_type, alignment>::value)),
&value,
sizeof(value_type));
}
} // end namespace endian
namespace detail {
template<typename value_type,
endianness endian,
std::size_t alignment>
struct packed_endian_specific_integral {
operator value_type() const {
return endian::read<value_type, endian, alignment>(
(const void*)Value.buffer);
}
void operator=(value_type newValue) {
endian::write<value_type, endian, alignment>(
(void*)Value.buffer, newValue);
}
packed_endian_specific_integral &operator+=(value_type newValue) {
*this = *this + newValue;
return *this;
}
packed_endian_specific_integral &operator-=(value_type newValue) {
*this = *this - newValue;
return *this;
}
private:
AlignedCharArray<PickAlignment<value_type, alignment>::value,
sizeof(value_type)> Value;
public:
struct ref {
explicit ref(void *Ptr) : Ptr(Ptr) {}
operator value_type() const {
return endian::read<value_type, endian, alignment>(Ptr);
}
void operator=(value_type NewValue) {
endian::write<value_type, endian, alignment>(Ptr, NewValue);
}
private:
void *Ptr;
};
};
} // end namespace detail
typedef detail::packed_endian_specific_integral
<uint16_t, little, unaligned> ulittle16_t;
typedef detail::packed_endian_specific_integral
<uint32_t, little, unaligned> ulittle32_t;
typedef detail::packed_endian_specific_integral
<uint64_t, little, unaligned> ulittle64_t;
typedef detail::packed_endian_specific_integral
<int16_t, little, unaligned> little16_t;
typedef detail::packed_endian_specific_integral
<int32_t, little, unaligned> little32_t;
typedef detail::packed_endian_specific_integral
<int64_t, little, unaligned> little64_t;
typedef detail::packed_endian_specific_integral
<uint16_t, little, aligned> aligned_ulittle16_t;
typedef detail::packed_endian_specific_integral
<uint32_t, little, aligned> aligned_ulittle32_t;
typedef detail::packed_endian_specific_integral
<uint64_t, little, aligned> aligned_ulittle64_t;
typedef detail::packed_endian_specific_integral
<int16_t, little, aligned> aligned_little16_t;
typedef detail::packed_endian_specific_integral
<int32_t, little, aligned> aligned_little32_t;
typedef detail::packed_endian_specific_integral
<int64_t, little, aligned> aligned_little64_t;
typedef detail::packed_endian_specific_integral
<uint16_t, big, unaligned> ubig16_t;
typedef detail::packed_endian_specific_integral
<uint32_t, big, unaligned> ubig32_t;
typedef detail::packed_endian_specific_integral
<uint64_t, big, unaligned> ubig64_t;
typedef detail::packed_endian_specific_integral
<int16_t, big, unaligned> big16_t;
typedef detail::packed_endian_specific_integral
<int32_t, big, unaligned> big32_t;
typedef detail::packed_endian_specific_integral
<int64_t, big, unaligned> big64_t;
typedef detail::packed_endian_specific_integral
<uint16_t, big, aligned> aligned_ubig16_t;
typedef detail::packed_endian_specific_integral
<uint32_t, big, aligned> aligned_ubig32_t;
typedef detail::packed_endian_specific_integral
<uint64_t, big, aligned> aligned_ubig64_t;
typedef detail::packed_endian_specific_integral
<int16_t, big, aligned> aligned_big16_t;
typedef detail::packed_endian_specific_integral
<int32_t, big, aligned> aligned_big32_t;
typedef detail::packed_endian_specific_integral
<int64_t, big, aligned> aligned_big64_t;
typedef detail::packed_endian_specific_integral
<uint16_t, native, unaligned> unaligned_uint16_t;
typedef detail::packed_endian_specific_integral
<uint32_t, native, unaligned> unaligned_uint32_t;
typedef detail::packed_endian_specific_integral
<uint64_t, native, unaligned> unaligned_uint64_t;
typedef detail::packed_endian_specific_integral
<int16_t, native, unaligned> unaligned_int16_t;
typedef detail::packed_endian_specific_integral
<int32_t, native, unaligned> unaligned_int32_t;
typedef detail::packed_endian_specific_integral
<int64_t, native, unaligned> unaligned_int64_t;
namespace endian {
inline uint16_t read16le(const void *p) { return *(const ulittle16_t *)p; }
inline uint32_t read32le(const void *p) { return *(const ulittle32_t *)p; }
inline uint64_t read64le(const void *p) { return *(const ulittle64_t *)p; }
inline uint16_t read16be(const void *p) { return *(const ubig16_t *)p; }
inline uint32_t read32be(const void *p) { return *(const ubig32_t *)p; }
inline uint64_t read64be(const void *p) { return *(const ubig64_t *)p; }
inline void write16le(void *p, uint16_t v) { *(ulittle16_t *)p = v; }
inline void write32le(void *p, uint32_t v) { *(ulittle32_t *)p = v; }
inline void write64le(void *p, uint64_t v) { *(ulittle64_t *)p = v; }
inline void write16be(void *p, uint16_t v) { *(ubig16_t *)p = v; }
inline void write32be(void *p, uint32_t v) { *(ubig32_t *)p = v; }
inline void write64be(void *p, uint64_t v) { *(ubig64_t *)p = v; }
} // end namespace endian
} // end namespace support
} // end namespace llvm
#endif
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