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569
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1 /* xstrtod.c - error-checking interface to strtod |
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2 Copyright (C) 1996 Free Software Foundation, Inc. |
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3 |
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4 This program is free software; you can redistribute it and/or modify |
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5 it under the terms of the GNU General Public License as published by |
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6 the Free Software Foundation; either version 2, or (at your option) |
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7 any later version. |
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8 |
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9 This program is distributed in the hope that it will be useful, |
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10 but WITHOUT ANY WARRANTY; without even the implied warranty of |
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11 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the |
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12 GNU General Public License for more details. |
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13 |
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14 You should have received a copy of the GNU General Public License |
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15 along with this program; if not, write to the Free Software |
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16 Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA. */ |
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17 |
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18 /* Written by Jim Meyering. */ |
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19 |
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513
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20 #ifdef HAVE_CONFIG_H |
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21 #include <config.h> |
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22 #endif |
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23 |
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24 #ifdef STDC_HEADERS |
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25 #include <stdlib.h> |
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26 #else |
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27 double strtod (); |
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28 #endif |
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29 |
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30 #include <errno.h> |
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31 #include <stdio.h> |
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32 #include <limits.h> |
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33 #include "xstrtod.h" |
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34 |
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35 /* An interface to strtod that encapsulates all the error checking |
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36 one should usually perform. Like strtod, but upon successful |
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37 conversion put the result in *RESULT and return zero. Return |
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38 non-zero and don't modify *RESULT upon any failure. */ |
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39 |
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513
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40 int |
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41 xstrtod (str, ptr, result) |
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42 const char *str; |
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43 const char **ptr; |
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44 double *result; |
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45 { |
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46 double val; |
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47 char *terminator; |
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48 int fail; |
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49 |
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50 fail = 0; |
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51 errno = 0; |
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52 val = strtod (str, &terminator); |
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53 |
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54 /* Having a non-zero terminator is an error only when PTR is NULL. */ |
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55 if (terminator == str || (ptr == NULL && *terminator != '\0')) |
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56 fail = 1; |
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57 else |
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58 { |
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59 /* Allow underflow (in which case strtod returns zero), |
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60 but flag overflow as an error. */ |
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61 if (val != 0.0 && errno == ERANGE) |
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62 fail = 1; |
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63 } |
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64 |
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65 if (ptr != NULL) |
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66 *ptr = terminator; |
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67 |
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68 *result = val; |
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69 return fail; |
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70 } |
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71 |
