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1 /*
2  *
3  * (C) Copyright IBM Corp. 1998-2010 - All Rights Reserved
4  *
5  */
6 
7 #ifndef __LESWAPS_H
8 #define __LESWAPS_H
9 
10 #include "LETypes.h"
11 
12 /**
13  * \file
14  * \brief C++ API: Endian independent access to data for LayoutEngine
15  */
16 
17 U_NAMESPACE_BEGIN
18 
19 /**
20  * A convenience macro which invokes the swapWord member function
21  * from a concise call.
22  *
23  * @stable ICU 2.8
24  */
25 #define SWAPW(value) LESwaps::swapWord((le_uint16)(value))
26 
27 /**
28  * A convenience macro which invokes the swapLong member function
29  * from a concise call.
30  *
31  * @stable ICU 2.8
32  */
33 #define SWAPL(value) LESwaps::swapLong((le_uint32)(value))
34 
35 /**
36  * This class is used to access data which stored in big endian order
37  * regardless of the conventions of the platform.
38  *
39  * All methods are static and inline in an attempt to induce the compiler
40  * to do most of the calculations at compile time.
41  *
42  * @stable ICU 2.8
43  */
44 class U_LAYOUT_API LESwaps /* not : public UObject because all methods are static */ {
45 public:
46 
47     /**
48      * This method does the byte swap required on little endian platforms
49      * to correctly access a (16-bit) word.
50      *
51      * @param value - the word to be byte swapped
52      *
53      * @return the byte swapped word
54      *
55      * @stable ICU 2.8
56      */
swapWord(le_uint16 value)57     static le_uint16 swapWord(le_uint16 value)
58     {
59         return (le_uint16)((value << 8) | (value >> 8));
60     };
61 
62     /**
63      * This method does the byte swapping required on little endian platforms
64      * to correctly access a (32-bit) long.
65      *
66      * @param value - the long to be byte swapped
67      *
68      * @return the byte swapped long
69      *
70      * @stable ICU 2.8
71      */
swapLong(le_uint32 value)72     static le_uint32 swapLong(le_uint32 value)
73     {
74         return (le_uint32)(
75             (value << 24) |
76             ((value << 8) & 0xff0000) |
77             ((value >> 8) & 0xff00) |
78             (value >> 24));
79     };
80 
81 private:
LESwaps()82     LESwaps() {} // private - forbid instantiation
83 };
84 
85 U_NAMESPACE_END
86 #endif
87