1 martin 1.6 //%LICENSE////////////////////////////////////////////////////////////////
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2 martin 1.7 //
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3 martin 1.6 // Licensed to The Open Group (TOG) under one or more contributor license
4 // agreements. Refer to the OpenPegasusNOTICE.txt file distributed with
5 // this work for additional information regarding copyright ownership.
6 // Each contributor licenses this file to you under the OpenPegasus Open
7 // Source License; you may not use this file except in compliance with the
8 // License.
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9 martin 1.7 //
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10 martin 1.6 // Permission is hereby granted, free of charge, to any person obtaining a
11 // copy of this software and associated documentation files (the "Software"),
12 // to deal in the Software without restriction, including without limitation
13 // the rights to use, copy, modify, merge, publish, distribute, sublicense,
14 // and/or sell copies of the Software, and to permit persons to whom the
15 // Software is furnished to do so, subject to the following conditions:
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16 martin 1.7 //
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17 martin 1.6 // The above copyright notice and this permission notice shall be included
18 // in all copies or substantial portions of the Software.
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19 martin 1.7 //
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20 martin 1.6 // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS
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21 martin 1.7 // OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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22 martin 1.6 // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
23 // IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
24 // CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
25 // TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
26 // SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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27 martin 1.7 //
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28 martin 1.6 //////////////////////////////////////////////////////////////////////////
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29 mike 1.1 //
30 //%/////////////////////////////////////////////////////////////////////////////
31
32 #ifndef Pegasus_StrLit_h
33 #define Pegasus_StrLit_h
34
35 #include <Pegasus/Common/Config.h>
36 #include <Pegasus/Common/Buffer.h>
37
38 #define STRLIT_ARGS(STR) STR, (sizeof(STR)-1)
39 #define STRLIT(STR) StrLit(STRLIT_ARGS(STR))
40
41 PEGASUS_NAMESPACE_BEGIN
42
43 /* The StrLit class and associated macros provide a mechanism for retaining the
44 length C string literals at compile time. This is preferrable to repeated
45 recalculation of the length, usually with strlen(). For example, this:
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46 kumpf 1.4
47 String s("hello world");
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48 mike 1.1
49 Is less efficient than this:
50
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51 kumpf 1.4 String s("hello world", 11);
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52 mike 1.1
53 The first form, forces the String constructor to call strlen(), an O(N)
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54 kumpf 1.4 operation. This is unfortunate for C string literals since the length can
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55 mike 1.1 be obtained at compile time with the sizeof operator. For example:
56
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57 kumpf 1.4 String s("hello world", sizeof("hello world") - 1);
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58 mike 1.1
59 But repeating the literal twice is error prone, so instead we use the
60 STRLIT_ARGS() macro.
61
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62 kumpf 1.4 String s(STRLIT_ARGS("hello world"));
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63 mike 1.1
64 This macro can also be used to define StrLit objects at compile time.
65 For example:
66
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67 kumpf 1.4 const StrLit DEFAULT_HOSTNAME(STRLIT_ARGS("localhost"));
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68 mike 1.1
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69 kumpf 1.4 You can implement functions that take StrLit objects. For example, we
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70 mike 1.1 define this function:
71
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72 kumpf 1.4 operator<<(const Buffer&, const StrLit&);
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73 mike 1.1
74 This function can be used in two ways. You can pass predefined StrLit
75 object to it like this:
76
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77 kumpf 1.4 Buffer out;
78 out << DEFAULT_HOSTNAME;
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79 mike 1.1
80 Or you can use the STRLIT() macro to construct on on the fly:
81
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82 kumpf 1.4 Buffer out;
83 out << STRLIT("localhost");
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84 mike 1.1
85 Note that the latter form would be faster than this, since somebody
86 is going to have to call strlen() eventually.
87
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88 kumpf 1.4 Buffer out;
89 out << "localhost";
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90 mike 1.1
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91 kumpf 1.4 At first glance, this may seem like a small optimization, but this
92 technique alone was used to decrease the Pegasus CIM server latency
93 by ten percent (with only moderate application to the XML marshalling
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94 mike 1.1 routines).
95 */
96 struct StrLit
97 {
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98 kumpf 1.5 StrLit(const char* s, size_t n) : str(s), size((Uint32)n) { }
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99 mike 1.1 const char* str;
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100 kumpf 1.5 const Uint32 size;
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101 mike 1.1 };
102
103 inline Buffer& operator<<(Buffer& out, const StrLit& x)
104 {
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105 mike 1.2 out.append(x.str, x.size);
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106 mike 1.1 return out;
107 }
108
109 PEGASUS_NAMESPACE_END
110
111 #endif /* Pegasus_StrLit_h */
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