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 <limits.h>
45
46 namespace Imf {
47 namespace {
48
49 inline bool
isNegative(float f)50 isNegative (float f)
51 {
52 union {float f; int i;} u;
53 u.f = f;
54 return (u.i & 0x80000000) != 0;
55 }
56
57
58 inline bool
isNan(float f)59 isNan (float f)
60 {
61 union {float f; int i;} u;
62 u.f = f;
63 return (u.i & 0x7fffffff) > 0x7f800000;
64 }
65
66
67 inline bool
isInfinity(float f)68 isInfinity (float f)
69 {
70 union {float f; int i;} u;
71 u.f = f;
72 return (u.i & 0x7fffffff) == 0x7f800000;
73 }
74
75
76 inline bool
isFinite(float f)77 isFinite (float f)
78 {
79 union {float f; int i;} u;
80 u.f = f;
81 return (u.i & 0x7f800000) != 0x7f800000;
82 }
83
84 } // namespace
85
86
87 unsigned int
halfToUint(half h)88 halfToUint (half h)
89 {
90 if (h.isNegative() || h.isNan())
91 return 0;
92
93 if (h.isInfinity())
94 return UINT_MAX;
95
96 return (unsigned int) h;
97 }
98
99
100 unsigned int
floatToUint(float f)101 floatToUint (float f)
102 {
103 if (isNegative (f) || isNan (f))
104 return 0;
105
106 if (isInfinity (f) || f > UINT_MAX)
107 return UINT_MAX;
108
109 return (unsigned int) f;
110 }
111
112
113 half
uintToHalf(unsigned int ui)114 uintToHalf (unsigned int ui)
115 {
116 if (ui > HALF_MAX)
117 return half::posInf();
118
119 return half (ui);
120 }
121
122
123 half
floatToHalf(float f)124 floatToHalf (float f)
125 {
126 if (isFinite (f))
127 {
128 if (f > HALF_MAX)
129 return half::posInf();
130
131 if (f < -HALF_MAX)
132 return half::negInf();
133 }
134
135 return half (f);
136 }
137
138
139 } // namespace Imf
140