mirror of https://github.com/aria2/aria2
112 lines
3.2 KiB
C++
112 lines
3.2 KiB
C++
/* Any copyright is dedicated to the Public Domain.
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* http://creativecommons.org/publicdomain/zero/1.0/ */
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// Written in 2014 by Nils Maier
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#ifndef CRYPTO_ENDIAN_H
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#define CRYPTO_ENDIAN_H
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#include <cstdint>
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#include "config.h"
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namespace crypto {
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#if defined(__GNUG__)
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# define forceinline __attribute__((always_inline)) inline
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#elif defined(_MSC_VER)
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# define forceinline __forceinline
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#else // ! _MSC_VER
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# define forceinline inline
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#endif // ! _MSC_VER
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/* In order for this implementation to work your system (or you yourself) must
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* define after including <sys/param.h>
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* - LITTLE_ENDIAN
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* - BIG_ENDIAN
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* - BYTE_ORDER
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* - where BYTE_ORDER == LITTLE_ENDIAN or BYTE_ORDER == BIG_ENDIAN
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* Failing to conform will render this implementation utterly incorrect.
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*/
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#if defined(_WIN32) || defined(__INTEL_COMPILER) || defined(_MSC_VER)
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// Itanium is dead!
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# define LITTLE_ENDIAN 1234
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# define BIG_ENDIAN 4321
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# define BYTE_ORDER LITTLE_ENDIAN
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#else // ! defined(_WIN32) || defined(__INTEL_COMPILER) || defined (_MSC_VER)
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# ifdef HAVE_SYS_PARAM_H
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# include <sys/param.h>
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# endif // HAVE_SYS_PARAM_H
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#endif // ! defined(_WIN32) || defined(__INTEL_COMPILER) || defined (_MSC_VER)
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#if !defined(LITTLE_ENDIAN) || !defined(BIG_ENDIAN) || !defined(BYTE_ORDER) || \
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(LITTLE_ENDIAN != BYTE_ORDER && BIG_ENDIAN != BYTE_ORDER)
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# error Unsupported byte order/endianness
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#endif
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// Lets spend some quality time mucking around with byte swap and endian-ness.
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// First bswap32:
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#if (defined(__i386__) || defined(__x86_64__)) && defined(__GNUG__)
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forceinline uint32_t __crypto_bswap32(uint32_t p)
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{
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__asm__ __volatile__("bswap %0" : "=r"(p) : "0"(p));
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return p;
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}
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#elif defined(__GNUG__)
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# define __crypto_bswap32 __builtin_bswap32
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#else // defined(__GNUG__)
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forceinline uint32_t __crypto_bswap32(uint32_t n)
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{
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n = ((n << 8) & 0xff00ff00) | ((n >> 8) & 0xff00ff);
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return (n << 16) | (n >> 16);
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}
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#endif // defined(__GNUG__)
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// Next up: bswap64
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#if defined(__x86_64__) && defined(__GNUG__)
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forceinline uint64_t __crypto_bswap64(uint64_t p)
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{
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__asm__ __volatile__("bswapq %q0" : "=r"(p) : "0"(p));
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return p;
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}
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#elif defined(__GNUG__)
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# define __crypto_bswap64 __builtin_bswap64
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#else // defined(__GNUG__)
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forceinline uint64_t __crypto_bswap64(uint64_t n)
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{
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n = ((n << 8) & 0xff00ff00ff00ff00) | ((n >> 8) & 0x00ff00ff00ff00ff);
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n = ((n << 16) & 0xffff0000ffff0000) | ((n >> 16) & 0x0000ffff0000ffff);
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return (n << 32) | (n >> 32);
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}
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#endif // defined(__GNUG__)
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// Time for an implementation that makes reuse easier.
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namespace {
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template <typename T> inline T __crypto_bswap(T n)
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{
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static_assert(sizeof(T) != sizeof(T), "Not implemented");
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}
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template <> inline uint32_t __crypto_bswap(uint32_t n)
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{
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return __crypto_bswap32(n);
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}
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template <> inline uint64_t __crypto_bswap(uint64_t n)
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{
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return __crypto_bswap64(n);
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}
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} // namespace
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// __crypto_le and __crypto_be depending on byte order
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#if LITTLE_ENDIAN == BYTE_ORDER
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# define __crypto_be(n) __crypto_bswap(n)
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# define __crypto_le(n) (n)
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#else // LITTLE_ENDIAN != WORD_ORDER
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# define __crypto_be(n) (n)
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# define __crypto_le(n) __crypto_bswap(n)
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#endif // LITTLE_ENDIAN != WORD_ORDER
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} // namespace crypto
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#endif // CRYPTO_ENDIAN_H
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