272 lines
8.6 KiB
C++
272 lines
8.6 KiB
C++
// Copyright 2017 The Abseil Authors.
|
|
//
|
|
// Licensed under the Apache License, Version 2.0 (the "License");
|
|
// you may not use this file except in compliance with the License.
|
|
// You may obtain a copy of the License at
|
|
//
|
|
// https://www.apache.org/licenses/LICENSE-2.0
|
|
//
|
|
// Unless required by applicable law or agreed to in writing, software
|
|
// distributed under the License is distributed on an "AS IS" BASIS,
|
|
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
|
|
// See the License for the specific language governing permissions and
|
|
// limitations under the License.
|
|
//
|
|
|
|
#ifndef ABSL_BASE_INTERNAL_ENDIAN_H_
|
|
#define ABSL_BASE_INTERNAL_ENDIAN_H_
|
|
|
|
// The following guarantees declaration of the byte swap functions
|
|
#ifdef _MSC_VER
|
|
#include <stdlib.h> // NOLINT(build/include)
|
|
#elif defined(__APPLE__)
|
|
// Mac OS X / Darwin features
|
|
#include <libkern/OSByteOrder.h>
|
|
#elif defined(__FreeBSD__)
|
|
#include <sys/endian.h>
|
|
#elif defined(__GLIBC__)
|
|
#include <byteswap.h> // IWYU pragma: export
|
|
#endif
|
|
|
|
#include <cstdint>
|
|
#include "absl/base/config.h"
|
|
#include "absl/base/internal/unaligned_access.h"
|
|
#include "absl/base/port.h"
|
|
|
|
namespace absl {
|
|
|
|
// Use compiler byte-swapping intrinsics if they are available. 32-bit
|
|
// and 64-bit versions are available in Clang and GCC as of GCC 4.3.0.
|
|
// The 16-bit version is available in Clang and GCC only as of GCC 4.8.0.
|
|
// For simplicity, we enable them all only for GCC 4.8.0 or later.
|
|
#if defined(__clang__) || \
|
|
(defined(__GNUC__) && \
|
|
((__GNUC__ == 4 && __GNUC_MINOR__ >= 8) || __GNUC__ >= 5))
|
|
inline uint64_t gbswap_64(uint64_t host_int) {
|
|
return __builtin_bswap64(host_int);
|
|
}
|
|
inline uint32_t gbswap_32(uint32_t host_int) {
|
|
return __builtin_bswap32(host_int);
|
|
}
|
|
inline uint16_t gbswap_16(uint16_t host_int) {
|
|
return __builtin_bswap16(host_int);
|
|
}
|
|
|
|
#elif defined(_MSC_VER)
|
|
inline uint64_t gbswap_64(uint64_t host_int) {
|
|
return _byteswap_uint64(host_int);
|
|
}
|
|
inline uint32_t gbswap_32(uint32_t host_int) {
|
|
return _byteswap_ulong(host_int);
|
|
}
|
|
inline uint16_t gbswap_16(uint16_t host_int) {
|
|
return _byteswap_ushort(host_int);
|
|
}
|
|
|
|
#elif defined(__APPLE__)
|
|
inline uint64_t gbswap_64(uint64_t host_int) { return OSSwapInt16(host_int); }
|
|
inline uint32_t gbswap_32(uint32_t host_int) { return OSSwapInt32(host_int); }
|
|
inline uint16_t gbswap_16(uint16_t host_int) { return OSSwapInt64(host_int); }
|
|
|
|
#else
|
|
inline uint64_t gbswap_64(uint64_t host_int) {
|
|
#if defined(__GNUC__) && defined(__x86_64__) && !defined(__APPLE__)
|
|
// Adapted from /usr/include/byteswap.h. Not available on Mac.
|
|
if (__builtin_constant_p(host_int)) {
|
|
return __bswap_constant_64(host_int);
|
|
} else {
|
|
uint64_t result;
|
|
__asm__("bswap %0" : "=r"(result) : "0"(host_int));
|
|
return result;
|
|
}
|
|
#elif defined(__GLIBC__)
|
|
return bswap_64(host_int);
|
|
#else
|
|
return (((host_int & uint64_t{0xFF}) << 56) |
|
|
((host_int & uint64_t{0xFF00}) << 40) |
|
|
((host_int & uint64_t{0xFF0000}) << 24) |
|
|
((host_int & uint64_t{0xFF000000}) << 8) |
|
|
((host_int & uint64_t{0xFF00000000}) >> 8) |
|
|
((host_int & uint64_t{0xFF0000000000}) >> 24) |
|
|
((host_int & uint64_t{0xFF000000000000}) >> 40) |
|
|
((host_int & uint64_t{0xFF00000000000000}) >> 56));
|
|
#endif // bswap_64
|
|
}
|
|
|
|
inline uint32_t gbswap_32(uint32_t host_int) {
|
|
#if defined(__GLIBC__)
|
|
return bswap_32(host_int);
|
|
#else
|
|
return (((host_int & uint32_t{0xFF}) << 24) |
|
|
((host_int & uint32_t{0xFF00}) << 8) |
|
|
((host_int & uint32_t{0xFF0000}) >> 8) |
|
|
((host_int & uint32_t{0xFF000000}) >> 24));
|
|
#endif
|
|
}
|
|
|
|
inline uint16_t gbswap_16(uint16_t host_int) {
|
|
#if defined(__GLIBC__)
|
|
return bswap_16(host_int);
|
|
#else
|
|
return (((host_int & uint16_t{0xFF}) << 8) |
|
|
((host_int & uint16_t{0xFF00}) >> 8));
|
|
#endif
|
|
}
|
|
|
|
#endif // intrinics available
|
|
|
|
#ifdef ABSL_IS_LITTLE_ENDIAN
|
|
|
|
// Definitions for ntohl etc. that don't require us to include
|
|
// netinet/in.h. We wrap gbswap_32 and gbswap_16 in functions rather
|
|
// than just #defining them because in debug mode, gcc doesn't
|
|
// correctly handle the (rather involved) definitions of bswap_32.
|
|
// gcc guarantees that inline functions are as fast as macros, so
|
|
// this isn't a performance hit.
|
|
inline uint16_t ghtons(uint16_t x) { return gbswap_16(x); }
|
|
inline uint32_t ghtonl(uint32_t x) { return gbswap_32(x); }
|
|
inline uint64_t ghtonll(uint64_t x) { return gbswap_64(x); }
|
|
|
|
#elif defined ABSL_IS_BIG_ENDIAN
|
|
|
|
// These definitions are simpler on big-endian machines
|
|
// These are functions instead of macros to avoid self-assignment warnings
|
|
// on calls such as "i = ghtnol(i);". This also provides type checking.
|
|
inline uint16_t ghtons(uint16_t x) { return x; }
|
|
inline uint32_t ghtonl(uint32_t x) { return x; }
|
|
inline uint64_t ghtonll(uint64_t x) { return x; }
|
|
|
|
#else
|
|
#error \
|
|
"Unsupported byte order: Either ABSL_IS_BIG_ENDIAN or " \
|
|
"ABSL_IS_LITTLE_ENDIAN must be defined"
|
|
#endif // byte order
|
|
|
|
inline uint16_t gntohs(uint16_t x) { return ghtons(x); }
|
|
inline uint32_t gntohl(uint32_t x) { return ghtonl(x); }
|
|
inline uint64_t gntohll(uint64_t x) { return ghtonll(x); }
|
|
|
|
// Utilities to convert numbers between the current hosts's native byte
|
|
// order and little-endian byte order
|
|
//
|
|
// Load/Store methods are alignment safe
|
|
namespace little_endian {
|
|
// Conversion functions.
|
|
#ifdef ABSL_IS_LITTLE_ENDIAN
|
|
|
|
inline uint16_t FromHost16(uint16_t x) { return x; }
|
|
inline uint16_t ToHost16(uint16_t x) { return x; }
|
|
|
|
inline uint32_t FromHost32(uint32_t x) { return x; }
|
|
inline uint32_t ToHost32(uint32_t x) { return x; }
|
|
|
|
inline uint64_t FromHost64(uint64_t x) { return x; }
|
|
inline uint64_t ToHost64(uint64_t x) { return x; }
|
|
|
|
inline constexpr bool IsLittleEndian() { return true; }
|
|
|
|
#elif defined ABSL_IS_BIG_ENDIAN
|
|
|
|
inline uint16_t FromHost16(uint16_t x) { return gbswap_16(x); }
|
|
inline uint16_t ToHost16(uint16_t x) { return gbswap_16(x); }
|
|
|
|
inline uint32_t FromHost32(uint32_t x) { return gbswap_32(x); }
|
|
inline uint32_t ToHost32(uint32_t x) { return gbswap_32(x); }
|
|
|
|
inline uint64_t FromHost64(uint64_t x) { return gbswap_64(x); }
|
|
inline uint64_t ToHost64(uint64_t x) { return gbswap_64(x); }
|
|
|
|
inline constexpr bool IsLittleEndian() { return false; }
|
|
|
|
#endif /* ENDIAN */
|
|
|
|
// Functions to do unaligned loads and stores in little-endian order.
|
|
inline uint16_t Load16(const void *p) {
|
|
return ToHost16(ABSL_INTERNAL_UNALIGNED_LOAD16(p));
|
|
}
|
|
|
|
inline void Store16(void *p, uint16_t v) {
|
|
ABSL_INTERNAL_UNALIGNED_STORE16(p, FromHost16(v));
|
|
}
|
|
|
|
inline uint32_t Load32(const void *p) {
|
|
return ToHost32(ABSL_INTERNAL_UNALIGNED_LOAD32(p));
|
|
}
|
|
|
|
inline void Store32(void *p, uint32_t v) {
|
|
ABSL_INTERNAL_UNALIGNED_STORE32(p, FromHost32(v));
|
|
}
|
|
|
|
inline uint64_t Load64(const void *p) {
|
|
return ToHost64(ABSL_INTERNAL_UNALIGNED_LOAD64(p));
|
|
}
|
|
|
|
inline void Store64(void *p, uint64_t v) {
|
|
ABSL_INTERNAL_UNALIGNED_STORE64(p, FromHost64(v));
|
|
}
|
|
|
|
} // namespace little_endian
|
|
|
|
// Utilities to convert numbers between the current hosts's native byte
|
|
// order and big-endian byte order (same as network byte order)
|
|
//
|
|
// Load/Store methods are alignment safe
|
|
namespace big_endian {
|
|
#ifdef ABSL_IS_LITTLE_ENDIAN
|
|
|
|
inline uint16_t FromHost16(uint16_t x) { return gbswap_16(x); }
|
|
inline uint16_t ToHost16(uint16_t x) { return gbswap_16(x); }
|
|
|
|
inline uint32_t FromHost32(uint32_t x) { return gbswap_32(x); }
|
|
inline uint32_t ToHost32(uint32_t x) { return gbswap_32(x); }
|
|
|
|
inline uint64_t FromHost64(uint64_t x) { return gbswap_64(x); }
|
|
inline uint64_t ToHost64(uint64_t x) { return gbswap_64(x); }
|
|
|
|
inline constexpr bool IsLittleEndian() { return true; }
|
|
|
|
#elif defined ABSL_IS_BIG_ENDIAN
|
|
|
|
inline uint16_t FromHost16(uint16_t x) { return x; }
|
|
inline uint16_t ToHost16(uint16_t x) { return x; }
|
|
|
|
inline uint32_t FromHost32(uint32_t x) { return x; }
|
|
inline uint32_t ToHost32(uint32_t x) { return x; }
|
|
|
|
inline uint64_t FromHost64(uint64_t x) { return x; }
|
|
inline uint64_t ToHost64(uint64_t x) { return x; }
|
|
|
|
inline constexpr bool IsLittleEndian() { return false; }
|
|
|
|
#endif /* ENDIAN */
|
|
|
|
// Functions to do unaligned loads and stores in big-endian order.
|
|
inline uint16_t Load16(const void *p) {
|
|
return ToHost16(ABSL_INTERNAL_UNALIGNED_LOAD16(p));
|
|
}
|
|
|
|
inline void Store16(void *p, uint16_t v) {
|
|
ABSL_INTERNAL_UNALIGNED_STORE16(p, FromHost16(v));
|
|
}
|
|
|
|
inline uint32_t Load32(const void *p) {
|
|
return ToHost32(ABSL_INTERNAL_UNALIGNED_LOAD32(p));
|
|
}
|
|
|
|
inline void Store32(void *p, uint32_t v) {
|
|
ABSL_INTERNAL_UNALIGNED_STORE32(p, FromHost32(v));
|
|
}
|
|
|
|
inline uint64_t Load64(const void *p) {
|
|
return ToHost64(ABSL_INTERNAL_UNALIGNED_LOAD64(p));
|
|
}
|
|
|
|
inline void Store64(void *p, uint64_t v) {
|
|
ABSL_INTERNAL_UNALIGNED_STORE64(p, FromHost64(v));
|
|
}
|
|
|
|
} // namespace big_endian
|
|
|
|
} // namespace absl
|
|
|
|
#endif // ABSL_BASE_INTERNAL_ENDIAN_H_
|