pv_endian.h

00001 // ----------------------------------------------------------------------------
00002 // Copyright 2016-2017 ARM Ltd.
00003 //  
00004 // Licensed under the Apache License, Version 2.0 (the "License");
00005 // you may not use this file except in compliance with the License.
00006 // You may obtain a copy of the License at
00007 //  
00008 //     http://www.apache.org/licenses/LICENSE-2.0
00009 //  
00010 // Unless required by applicable law or agreed to in writing, software
00011 // distributed under the License is distributed on an "AS IS" BASIS,
00012 // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
00013 // See the License for the specific language governing permissions and
00014 // limitations under the License.
00015 // ----------------------------------------------------------------------------
00016 
00017 #ifndef __PV_ENDIAN_H__
00018 #define __PV_ENDIAN_H__
00019 
00020 #include <inttypes.h>
00021 
00022 
00023 #ifdef __cplusplus
00024 extern "C" {
00025 #endif
00026 
00027 /** @file pv_endian.h
00028  *
00029  *    Utility functions that treats endianness.
00030  */
00031 
00032 
00033 /** Converts a little endian 32 bit integer to the host endianness, in a platform independent manner.
00034  *
00035  *  @param le32  [in] 32 bit integer in little endian format.   
00036  *
00037  *  @returns
00038  *      32 bit integer in host endianness format.
00039  */
00040 static inline uint32_t pv_le32_to_h(uint32_t le32)
00041 {
00042     const uint8_t* le32ptr = (uint8_t*)&le32;
00043     return (le32ptr[0] << 0)  +
00044            (le32ptr[1] << 8)  +
00045            (le32ptr[2] << 16) +
00046            (le32ptr[3] << 24);
00047 }
00048 
00049 /** Converts a big endian 32 bit integer to the host endianness, in a platform independent manner.
00050  *
00051  *  @param be32  [in] 32 bit integer in big endian format.
00052  *
00053  *  @returns
00054  *      32 bit integer in host endianness format.
00055  */
00056 static inline uint32_t pv_be32_to_h(uint32_t be32)
00057 {
00058     const uint8_t* be32ptr = (uint8_t*)&be32;
00059     return (be32ptr[0] << 24) +
00060            (be32ptr[1] << 16) +
00061            (be32ptr[2] << 8)  +
00062            (be32ptr[3] << 0);
00063 }
00064 
00065 
00066 /**  Converts a host endianness 32 bit integer to little endian, in a platform independent manner.
00067  * 
00068  *    @param host32  [in] 32 bit integer in host endianness format
00069  *
00070  *    @returns 
00071  *        32 bit integer in little endian format.
00072  */
00073 static inline uint32_t pv_h_to_le32(uint32_t host32)
00074 {
00075     uint32_t le32;
00076     uint8_t *le32_ptr = (uint8_t*)&le32;
00077 
00078     le32_ptr[0] = (host32 >> 0)  & 0xff;
00079     le32_ptr[1] = (host32 >> 8)  & 0xff;
00080     le32_ptr[2] = (host32 >> 16) & 0xff;
00081     le32_ptr[3] = (uint8_t)(host32 >> 24) & 0xff;
00082 
00083     /*@-usedef@*/
00084     // le32 is being initialized through a pointer.
00085     return le32;
00086     /*@+usedef@*/
00087 }
00088 
00089 
00090 /** Converts a host endianness 32 bit integer to big endian, in a platform independent manner.
00091  *
00092  *    @param host32  [in] 32 bit integer in host endianness format
00093  *
00094  *    @returns
00095  *       32 bit integer in big endian format.
00096  */
00097 static inline uint32_t pv_h_to_be32(uint32_t host32)
00098 {
00099     uint32_t be32;
00100     uint8_t *be32_ptr = (uint8_t*)&be32;
00101 
00102     be32_ptr[0] = (uint8_t)(host32 >> 24) & 0xff;
00103     be32_ptr[1] = (host32 >> 16) & 0xff;
00104     be32_ptr[2] = (host32 >> 8)  & 0xff;
00105     be32_ptr[3] = (host32 >> 0)  & 0xff;
00106 
00107     /*@-usedef@*/
00108     // be32 is being initialized through a pointer.
00109     return be32;
00110     /*@+usedef@*/
00111 }
00112 
00113 #ifdef __cplusplus
00114 }
00115 #endif
00116 
00117 #endif  // __PV_ENDIAN_H__
00118