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1 // Copyright (c) 1997-2009 Nokia Corporation and/or its subsidiary(-ies). |
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2 // All rights reserved. |
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3 // This component and the accompanying materials are made available |
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4 // under the terms of "Eclipse Public License v1.0" |
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5 // which accompanies this distribution, and is available |
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6 // at the URL "http://www.eclipse.org/legal/epl-v10.html". |
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7 // |
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8 // Initial Contributors: |
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9 // Nokia Corporation - initial contribution. |
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10 // |
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11 // Contributors: |
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12 // |
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13 // Description: |
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14 // FUNCTION |
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15 // <<atof>>, <<atoff>>---string to double or float |
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16 // INDEX |
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17 // atof |
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18 // INDEX |
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19 // atoff |
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20 // ANSI_SYNOPSIS |
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21 // |
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22 |
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23 // #include <stdlib.h> |
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24 // double atof(const char *<[s]>); |
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25 // float atoff(const char *<[s]>); |
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26 // TRAD_SYNOPSIS |
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27 // #include <stdlib.h> |
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28 // double atof(<[s]>) |
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29 // char *<[s]>; |
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30 // float atoff(<[s]>) |
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31 // char *<[s]>; |
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32 // <<atof>> converts the initial portion of a string to a <<double>>. |
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33 // <<atoff>> converts the initial portion of a string to a <<float>>. |
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34 // The functions parse the character string <[s]>, |
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35 // locating a substring which can be converted to a floating point |
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36 // value. The substring must match the format: |
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37 // . [+|-]<[digits]>[.][<[digits]>][(e|E)[+|-]<[digits]>] |
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38 // The substring converted is the longest initial |
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39 // fragment of <[s]> that has the expected format, beginning with |
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40 // the first non-whitespace character. The substring |
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41 // is empty if <<str>> is empty, consists entirely |
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42 // of whitespace, or if the first non-whitespace character is |
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43 // something other than <<+>>, <<->>, <<.>>, or a digit. |
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44 // <<atof(<[s]>)>> is implemented as <<strtod(<[s]>, NULL)>>. |
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45 // <<atoff(<[s]>)>> is implemented as <<strtodf(<[s]>, NULL)>>. |
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46 // RETURNS |
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47 // <<atof>> returns the converted substring value, if any, as a |
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48 // <<double>>; or <<0.0>>, if no conversion could be performed. |
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49 // If the correct value is out of the range of representable values, plus |
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50 // or minus <<HUGE_VAL>> is returned, and <<ERANGE>> is stored in |
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51 // <<errno>>. |
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52 // If the correct value would cause underflow, <<0.0>> is returned |
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53 // and <<ERANGE>> is stored in <<errno>>. |
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54 // <<atoff>> obeys the same rules as <<atof>>, except that it |
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55 // returns a <<float>>. |
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56 // PORTABILITY |
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57 // <<atof>> is ANSI C. <<atof>>, <<atoi>>, and <<atol>> are subsumed by <<strtod>> |
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58 // and <<strtol>>, but are used extensively in existing code. These functions are |
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59 // less reliable, but may be faster if the argument is verified to be in a valid |
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60 // range. |
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61 // Supporting OS subroutines required: <<close>>, <<fstat>>, <<isatty>>, |
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62 // <<lseek>>, <<read>>, <<sbrk>>, <<write>>. |
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63 // |
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64 |
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65 #include <e32std.h> |
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66 #include <stdlib.h> |
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67 #include <errno.h> |
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68 #include <math.h> |
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69 #include "../INC/ESTLIB.H" |
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70 extern "C" { |
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71 |
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72 /** |
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73 Convert string to double-precision floating-point value. |
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74 Parses string interpreting its content as a floating-point value |
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75 until a character that can not be interpreted is found, |
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76 and returns a double precision value. |
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77 @return The converted double value from the input string. |
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78 If an error occurs 0 is returned. |
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79 @param s String representing a floating point number. |
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80 @param tail Address of a pointer. |
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81 This is filled by the function with the address where scan has ended. |
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82 Serves to determine where there is the first non-numerical character in the string. |
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83 */ |
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84 EXPORT_C double strtod (const char *s, char** tail) __SOFTFP |
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85 { |
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86 TLex8 data=(unsigned char *)s; |
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87 TReal64 ret=0.0; |
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88 data.SkipSpace(); |
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89 TBool minus = data.Peek() == '-'; |
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90 TInt r=data.Val(ret); |
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91 if (r==KErrOverflow) |
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92 { |
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93 errno=ERANGE; |
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94 if (minus) |
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95 ret = -HUGE_VAL; |
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96 else |
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97 ret = HUGE_VAL; |
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98 } |
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99 else if (r==KErrUnderflow) |
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100 errno=ERANGE; |
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101 if (tail) |
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102 *tail=(char*)(s+data.Offset()); |
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103 return ret; |
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104 } |
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105 |
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106 /** |
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107 Convert string to double. |
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108 Parses string interpreting its content as a floating point number |
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109 and returns a value of type double. |
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110 @return The converted floating point value of the input string. |
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111 On overflow the result is undefined. |
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112 If an error occurs 0.0 is returned. |
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113 @param s String representing a floating point number. |
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114 */ |
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115 EXPORT_C double atof (const char *s) __SOFTFP |
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116 { |
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117 return strtod(s,NULL); |
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118 } |
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119 |
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120 } // extern "C" |