/* -*- mode: C++; c-basic-offset: 4; indent-tabs-mode: nil -*- */ // vim: ft=cpp:expandtab:ts=8:sw=4:softtabstop=4: #ident "$Id$" #ident "Copyright (c) 2007 Tokutek Inc. All rights reserved." /* Purpose of this file is to provide definitions of * Host to Disk byte transposition functions, an abstraction of * htod32()/dtoh32() and htod16()/dtoh16() functions. * * These htod/dtoh functions will only perform the transposition * if the disk and host are defined to be in opposite endian-ness. * If we define the disk to be in host order, then no byte * transposition is performed. (We might do this to save the * the time used for byte transposition.) * * This abstraction layer allows us to define the disk to be in * any byte order with a single compile-time switch (in htod.c). * * NOTE: THIS FILE DOES NOT CURRENTLY SUPPORT A BIG-ENDIAN * HOST AND A LITTLE-ENDIAN DISK. */ #ifndef _TOKU_HTOD_H #define _TOKU_HTOD_H #include #if defined(HAVE_ENDIAN_H) # include #elif defined(HAVE_MACHINE_ENDIAN_H) # include # define __BYTE_ORDER __DARWIN_BYTE_ORDER # define __LITTLE_ENDIAN __DARWIN_LITTLE_ENDIAN # define __BIG_ENDIAN __DARWIN_BIG_ENDIAN #endif #if !defined(__BYTE_ORDER) || \ !defined(__LITTLE_ENDIAN) || \ !defined(__BIG_ENDIAN) #error Standard endianness things not all defined #endif static const int64_t toku_byte_order_host = 0x0102030405060708LL; #define NETWORK_BYTE_ORDER (__BIG_ENDIAN) #define INTEL_BYTE_ORDER (__LITTLE_ENDIAN) #define HOST_BYTE_ORDER (__BYTE_ORDER) //DISK_BYTE_ORDER is the byte ordering for integers written to disk. //If DISK_BYTE_ORDER is the same as HOST_BYTE_ORDER no conversions are necessary. //Otherwise some structures require conversion to HOST_BYTE_ORDER on loading from disk (HOST_BYTE_ORDER in memory), and //others require conversion to HOST_BYTE_ORDER on every access/mutate (DISK_BYTE_ORDER in memory). #define DISK_BYTE_ORDER (INTEL_BYTE_ORDER) #if HOST_BYTE_ORDER!=INTEL_BYTE_ORDER //Even though the functions are noops if DISK==HOST, we do not have the logic to test whether the file was moved from another BYTE_ORDER machine. #error Only intel byte order supported so far. #endif #if DISK_BYTE_ORDER == HOST_BYTE_ORDER static inline uint64_t toku_dtoh64(uint64_t i) { return i; } static inline uint64_t toku_htod64(uint64_t i) { return i; } static inline uint32_t toku_dtoh32(uint32_t i) { return i; } static inline uint32_t toku_htod32(uint32_t i) { return i; } #else #error Not supported #endif #endif