/src/freeimage-svn/FreeImage/trunk/Source/OpenEXR/IlmImf/ImfConvert.cpp
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1 | | /////////////////////////////////////////////////////////////////////////// |
2 | | // |
3 | | // Copyright (c) 2002, Industrial Light & Magic, a division of Lucas |
4 | | // Digital Ltd. LLC |
5 | | // |
6 | | // All rights reserved. |
7 | | // |
8 | | // Redistribution and use in source and binary forms, with or without |
9 | | // modification, are permitted provided that the following conditions are |
10 | | // met: |
11 | | // * Redistributions of source code must retain the above copyright |
12 | | // notice, this list of conditions and the following disclaimer. |
13 | | // * Redistributions in binary form must reproduce the above |
14 | | // copyright notice, this list of conditions and the following disclaimer |
15 | | // in the documentation and/or other materials provided with the |
16 | | // distribution. |
17 | | // * Neither the name of Industrial Light & Magic nor the names of |
18 | | // its contributors may be used to endorse or promote products derived |
19 | | // from this software without specific prior written permission. |
20 | | // |
21 | | // THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS |
22 | | // "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT |
23 | | // LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR |
24 | | // A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT |
25 | | // OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, |
26 | | // SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT |
27 | | // LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
28 | | // DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
29 | | // THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
30 | | // (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE |
31 | | // OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
32 | | // |
33 | | /////////////////////////////////////////////////////////////////////////// |
34 | | |
35 | | |
36 | | //----------------------------------------------------------------------------- |
37 | | // |
38 | | // Routines for converting between pixel data types, |
39 | | // with well-defined behavior for exceptional cases. |
40 | | // |
41 | | //----------------------------------------------------------------------------- |
42 | | |
43 | | #include "ImfConvert.h" |
44 | | #include "ImfNamespace.h" |
45 | | |
46 | | #include <limits.h> |
47 | | |
48 | | |
49 | | OPENEXR_IMF_INTERNAL_NAMESPACE_SOURCE_ENTER |
50 | | |
51 | | namespace { |
52 | | |
53 | | inline bool |
54 | | isNegative (float f) |
55 | 0 | { |
56 | 0 | union {float f; int i;} u; |
57 | 0 | u.f = f; |
58 | 0 | return (u.i & 0x80000000) != 0; |
59 | 0 | } |
60 | | |
61 | | |
62 | | inline bool |
63 | | isNan (float f) |
64 | 0 | { |
65 | 0 | union {float f; int i;} u; |
66 | 0 | u.f = f; |
67 | 0 | return (u.i & 0x7fffffff) > 0x7f800000; |
68 | 0 | } |
69 | | |
70 | | |
71 | | inline bool |
72 | | isInfinity (float f) |
73 | 0 | { |
74 | 0 | union {float f; int i;} u; |
75 | 0 | u.f = f; |
76 | 0 | return (u.i & 0x7fffffff) == 0x7f800000; |
77 | 0 | } |
78 | | |
79 | | |
80 | | inline bool |
81 | | isFinite (float f) |
82 | 0 | { |
83 | 0 | union {float f; int i;} u; |
84 | 0 | u.f = f; |
85 | 0 | return (u.i & 0x7f800000) != 0x7f800000; |
86 | 0 | } |
87 | | |
88 | | } // namespace |
89 | | |
90 | | |
91 | | unsigned int |
92 | | halfToUint (half h) |
93 | 0 | { |
94 | 0 | if (h.isNegative() || h.isNan()) |
95 | 0 | return 0; |
96 | | |
97 | 0 | if (h.isInfinity()) |
98 | 0 | return UINT_MAX; |
99 | | |
100 | 0 | return (unsigned int) h; |
101 | 0 | } |
102 | | |
103 | | |
104 | | unsigned int |
105 | | floatToUint (float f) |
106 | 0 | { |
107 | 0 | if (isNegative (f) || isNan (f)) |
108 | 0 | return 0; |
109 | | |
110 | 0 | if (isInfinity (f) || f > UINT_MAX) |
111 | 0 | return UINT_MAX; |
112 | | |
113 | 0 | return (unsigned int) f; |
114 | 0 | } |
115 | | |
116 | | |
117 | | half |
118 | | uintToHalf (unsigned int ui) |
119 | 0 | { |
120 | 0 | if (ui > HALF_MAX) |
121 | 0 | return half::posInf(); |
122 | | |
123 | 0 | return half ((float) ui); |
124 | 0 | } |
125 | | |
126 | | |
127 | | half |
128 | | floatToHalf (float f) |
129 | 0 | { |
130 | 0 | if (isFinite (f)) |
131 | 0 | { |
132 | 0 | if (f > HALF_MAX) |
133 | 0 | return half::posInf(); |
134 | | |
135 | 0 | if (f < -HALF_MAX) |
136 | 0 | return half::negInf(); |
137 | 0 | } |
138 | | |
139 | 0 | return half (f); |
140 | 0 | } |
141 | | |
142 | | |
143 | | OPENEXR_IMF_INTERNAL_NAMESPACE_SOURCE_EXIT |