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comparison packages/language/c/libc/current/src/string/strlen.cxx @ 0:3111d98ba7b3 ecos-v1_1-release

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Initial commit of eCos version 1.1
author jlarmour
date Tue, 11 May 1999 11:16:07 +0000
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children 443894e2e912
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-1:000000000000 0:3111d98ba7b3
1 //===========================================================================
2 //
3 // strlen.cxx
4 //
5 // ANSI standard strlen() routine
6 //
7 //===========================================================================
8 //####COPYRIGHTBEGIN####
9 //
10 // -------------------------------------------
11 // The contents of this file are subject to the Cygnus eCos Public License
12 // Version 1.0 (the "License"); you may not use this file except in
13 // compliance with the License. You may obtain a copy of the License at
14 // http://sourceware.cygnus.com/ecos
15 //
16 // Software distributed under the License is distributed on an "AS IS"
17 // basis, WITHOUT WARRANTY OF ANY KIND, either express or implied. See the
18 // License for the specific language governing rights and limitations under
19 // the License.
20 //
21 // The Original Code is eCos - Embedded Cygnus Operating System, released
22 // September 30, 1998.
23 //
24 // The Initial Developer of the Original Code is Cygnus. Portions created
25 // by Cygnus are Copyright (C) 1998 Cygnus Solutions. All Rights Reserved.
26 // -------------------------------------------
27 //
28 //####COPYRIGHTEND####
29 //===========================================================================
30 //#####DESCRIPTIONBEGIN####
31 //
32 // Author(s): jlarmour
33 // Contributors: jlarmour@cygnus.co.uk
34 // Date: 1998-02-13
35 // Purpose:
36 // Description:
37 // Usage:
38 //
39 //####DESCRIPTIONEND####
40 //
41 //===========================================================================
42
43 // CONFIGURATION
44
45 #include <pkgconf/libc.h> // Configuration header
46
47 // Include the C library?
48 #ifdef CYGPKG_LIBC
49
50 // INCLUDES
51
52 #include <cyg/infra/cyg_type.h> // Common type definitions
53 #include <cyg/infra/cyg_trac.h> // Tracing support
54 #include <cyg/infra/cyg_ass.h> // Assertion support
55 #include <string.h> // Header for this file
56 #include <stddef.h> // Compiler definitions such as size_t, NULL etc.
57 #include "clibincl/stringsupp.hxx" // Useful string function support and
58 // prototypes
59
60 // EXPORTED SYMBOLS
61
62 externC size_t
63 strlen( const char *s ) CYGPRI_LIBC_WEAK_ALIAS("_strlen");
64
65 // FUNCTIONS
66
67 size_t
68 _strlen( const char *s )
69 {
70 int retval;
71
72 CYG_REPORT_FUNCNAMETYPE( "_strlen", "returning length %d" );
73 CYG_REPORT_FUNCARG1( "s=%08x", s );
74
75 CYG_CHECK_DATA_PTR( s, "s is not a valid pointer!" );
76
77 #if defined(CYGIMP_LIBC_STRING_PREFER_SMALL_TO_FAST) || defined(__OPTIMIZE_SIZE__)
78 const char *start = s;
79
80 while (*s)
81 s++;
82
83 retval = s - start;
84
85 CYG_REPORT_RETVAL( retval );
86
87 return retval;
88
89 #else
90
91 const char *start = s;
92 CYG_WORD *aligned_addr;
93
94 if (CYG_LIBC_STR_UNALIGNED (s))
95 {
96 while (*s)
97 s++;
98 retval = s - start;
99
100 CYG_REPORT_RETVAL( retval );
101
102 return retval;
103 }
104
105 // If the string is word-aligned, we can check for the presence of
106 // a null in each word-sized block.
107
108 aligned_addr = (CYG_WORD *)s;
109 while (!CYG_LIBC_STR_DETECTNULL (*aligned_addr))
110 aligned_addr++;
111
112 // Once a null is detected, we check each byte in that block for a
113 // precise position of the null.
114 s = (char*)aligned_addr;
115 while (*s)
116 s++;
117 retval = s - start;
118
119 CYG_REPORT_RETVAL( retval );
120
121 return retval;
122 #endif // not defined(CYGIMP_LIBC_STRING_PREFER_SMALL_TO_FAST) ||
123 // defined(__OPTIMIZE_SIZE__)
124 } // _strlen()
125
126 #endif // ifdef CYGPKG_LIBC
127
128 // EOF strlen.cxx