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