1 | /* |
2 | * Copyright (c) 2015, 2016, Oracle and/or its affiliates. All rights reserved. |
3 | * |
4 | * Redistribution and use in source and binary forms, with or without |
5 | * modification, are permitted provided that the following conditions |
6 | * are met: |
7 | * |
8 | * - Redistributions of source code must retain the above copyright |
9 | * notice, this list of conditions and the following disclaimer. |
10 | * |
11 | * - Redistributions in binary form must reproduce the above copyright |
12 | * notice, this list of conditions and the following disclaimer in the |
13 | * documentation and/or other materials provided with the distribution. |
14 | * |
15 | * - Neither the name of Oracle nor the names of its |
16 | * contributors may be used to endorse or promote products derived |
17 | * from this software without specific prior written permission. |
18 | * |
19 | * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS |
20 | * IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, |
21 | * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR |
22 | * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT OWNER OR |
23 | * CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, |
24 | * EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, |
25 | * PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR |
26 | * PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF |
27 | * LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING |
28 | * NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS |
29 | * SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
30 | */ |
31 | |
32 | #ifndef LIBJIMAGE_ENDIAN_HPP |
33 | #define LIBJIMAGE_ENDIAN_HPP |
34 | |
35 | #include "inttypes.hpp" |
36 | |
37 | // Selectable endian handling. Endian handlers are used when accessing values |
38 | // that are of unknown (until runtime) endian. The only requirement of the values |
39 | // accessed are that they are aligned to proper size boundaries (no misalignment.) |
40 | // To select an endian handler, one should call Endian::get_handler(big_endian); |
41 | // Where big_endian is true if big endian is required and false otherwise. The |
42 | // native endian handler can be fetched with Endian::get_native_handler(); |
43 | // To retrieve a value using the approprate endian, use one of the overloaded |
44 | // calls to get. To set a value, then use one of the overloaded set calls. |
45 | // Ex. |
46 | // s4 value; // Imported value; |
47 | // ... |
48 | // Endian* endian = Endian::get_handler(true); // Use big endian |
49 | // s4 corrected = endian->get(value); |
50 | // endian->set(value, 1); |
51 | // |
52 | class Endian { |
53 | public: |
54 | virtual u2 get(u2 x) = 0; |
55 | virtual u4 get(u4 x) = 0; |
56 | virtual u8 get(u8 x) = 0; |
57 | virtual s2 get(s2 x) = 0; |
58 | virtual s4 get(s4 x) = 0; |
59 | virtual s8 get(s8 x) = 0; |
60 | |
61 | virtual void set(u2& x, u2 y) = 0; |
62 | virtual void set(u4& x, u4 y) = 0; |
63 | virtual void set(u8& x, u8 y) = 0; |
64 | virtual void (s2& x, s2 y) = 0; |
65 | virtual void set(s4& x, s4 y) = 0; |
66 | virtual void set(s8& x, s8 y) = 0; |
67 | |
68 | // Quick little endian test. |
69 | static bool is_little_endian() { u4 x = 1; return *(u1 *)&x != 0; } |
70 | |
71 | // Quick big endian test. |
72 | static bool is_big_endian() { return !is_little_endian(); } |
73 | |
74 | // Select an appropriate endian handler. |
75 | static Endian* get_handler(bool big_endian); |
76 | |
77 | // Return the native endian handler. |
78 | static Endian* get_native_handler(); |
79 | |
80 | // get platform u2 from Java Big endian |
81 | static u2 get_java(u1* x); |
82 | // set platform u2 to Java Big endian |
83 | static void set_java(u1* p, u2 x); |
84 | }; |
85 | |
86 | // Normal endian handling. |
87 | class NativeEndian : public Endian { |
88 | private: |
89 | static NativeEndian _native; |
90 | |
91 | public: |
92 | u2 get(u2 x); |
93 | u4 get(u4 x); |
94 | u8 get(u8 x); |
95 | s2 get(s2 x); |
96 | s4 get(s4 x); |
97 | s8 get(s8 x); |
98 | |
99 | void set(u2& x, u2 y); |
100 | void set(u4& x, u4 y); |
101 | void set(u8& x, u8 y); |
102 | void (s2& x, s2 y); |
103 | void set(s4& x, s4 y); |
104 | void set(s8& x, s8 y); |
105 | |
106 | static Endian* get_native() { return &_native; } |
107 | }; |
108 | |
109 | // Swapping endian handling. |
110 | class SwappingEndian : public Endian { |
111 | private: |
112 | static SwappingEndian _swapping; |
113 | |
114 | public: |
115 | u2 get(u2 x); |
116 | u4 get(u4 x); |
117 | u8 get(u8 x); |
118 | s2 get(s2 x); |
119 | s4 get(s4 x); |
120 | s8 get(s8 x); |
121 | |
122 | void set(u2& x, u2 y); |
123 | void set(u4& x, u4 y); |
124 | void set(u8& x, u8 y); |
125 | void (s2& x, s2 y); |
126 | void set(s4& x, s4 y); |
127 | void set(s8& x, s8 y); |
128 | |
129 | static Endian* get_swapping() { return &_swapping; } |
130 | }; |
131 | #endif // LIBJIMAGE_ENDIAN_HPP |
132 | |