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      1 /*
      2  * Copyright (C) 2006 The Android Open Source Project
      3  *
      4  * Licensed under the Apache License, Version 2.0 (the "License");
      5  * you may not use this file except in compliance with the License.
      6  * You may obtain a copy of the License at
      7  *
      8  *      http://www.apache.org/licenses/LICENSE-2.0
      9  *
     10  * Unless required by applicable law or agreed to in writing, software
     11  * distributed under the License is distributed on an "AS IS" BASIS,
     12  * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
     13  * See the License for the specific language governing permissions and
     14  * limitations under the License.
     15  */
     16 
     17 //
     18 
     19 #ifndef _LIBS_UTILS_BYTE_ORDER_H
     20 #define _LIBS_UTILS_BYTE_ORDER_H
     21 
     22 #include <stdint.h>
     23 #include <sys/types.h>
     24 #ifdef HAVE_WINSOCK
     25 #include <winsock2.h>
     26 #else
     27 #include <netinet/in.h>
     28 #endif
     29 
     30 /*
     31  * These macros are like the hton/ntoh byte swapping macros,
     32  * except they allow you to swap to and from the "device" byte
     33  * order.  The device byte order is the endianness of the target
     34  * device -- for the ARM CPUs we use today, this is little endian.
     35  *
     36  * Note that the byte swapping functions have not been optimized
     37  * much; performance is currently not an issue for them since the
     38  * intent is to allow us to avoid byte swapping on the device.
     39  */
     40 
     41 static inline uint32_t android_swap_long(uint32_t v)
     42 {
     43     return (v<<24) | ((v<<8)&0x00FF0000) | ((v>>8)&0x0000FF00) | (v>>24);
     44 }
     45 
     46 static inline uint16_t android_swap_short(uint16_t v)
     47 {
     48     return (v<<8) | (v>>8);
     49 }
     50 
     51 #define DEVICE_BYTE_ORDER LITTLE_ENDIAN
     52 
     53 #if BYTE_ORDER == DEVICE_BYTE_ORDER
     54 
     55 #define	dtohl(x)	(x)
     56 #define	dtohs(x)	(x)
     57 #define	htodl(x)	(x)
     58 #define	htods(x)	(x)
     59 
     60 #else
     61 
     62 #define	dtohl(x)	(android_swap_long(x))
     63 #define	dtohs(x)	(android_swap_short(x))
     64 #define	htodl(x)	(android_swap_long(x))
     65 #define	htods(x)	(android_swap_short(x))
     66 
     67 #endif
     68 
     69 #if BYTE_ORDER == LITTLE_ENDIAN
     70 #define fromlel(x) (x)
     71 #define fromles(x) (x)
     72 #define tolel(x) (x)
     73 #define toles(x) (x)
     74 #else
     75 #define fromlel(x) (android_swap_long(x))
     76 #define fromles(x) (android_swap_short(x))
     77 #define tolel(x) (android_swap_long(x))
     78 #define toles(x) (android_swap_short(x))
     79 #endif
     80 
     81 #endif // _LIBS_UTILS_BYTE_ORDER_H
     82