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1 /* Compare strings while treating digits characters numerically. |
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2 Copyright (C) 1997 Free Software Foundation, Inc. |
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3 This file is part of the GNU C Library. |
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4 Contributed by Jean-Francois Bignolles <bignolle@ecoledoc.ibp.fr>, 1997. |
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5 |
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6 The GNU C Library is free software; you can redistribute it and/or |
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7 modify it under the terms of the GNU Library General Public License as |
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8 published by the Free Software Foundation; either version 2 of the |
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9 License, or (at your option) any later version. |
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10 |
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11 The GNU C Library is distributed in the hope that it will be useful, |
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12 but WITHOUT ANY WARRANTY; without even the implied warranty of |
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13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
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14 Library General Public License for more details. |
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15 |
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16 You should have received a copy of the GNU Library General Public |
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17 License along with the GNU C Library; see the file COPYING.LIB. If not, |
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18 write to the Free Software Foundation, Inc., 59 Temple Place - Suite 330, |
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19 Boston, MA 02111-1307, USA. */ |
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20 |
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21 #include <string.h> |
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22 #include <ctype.h> |
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23 |
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24 /* states: S_N: normal, S_I: comparing integral part, S_F: comparing |
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25 Fractional parts, S_Z: idem but with leading Zeroes only */ |
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26 #define S_N 0x0 |
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27 #define S_I 0x4 |
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28 #define S_F 0x8 |
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29 #define S_Z 0xC |
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30 |
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31 /* result_type: CMP: return diff; LEN: compare using len_diff/diff */ |
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32 #define CMP 2 |
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33 #define LEN 3 |
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34 |
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35 |
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36 /* Compare S1 and S2 as strings holding indices/version numbers, |
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37 returning less than, equal to or greater than zero if S1 is less than, |
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38 equal to or greater than S2 (for more info, see the texinfo doc). |
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39 */ |
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40 |
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41 int |
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42 strverscmp (s1, s2) |
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43 const char *s1; |
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44 const char *s2; |
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45 { |
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46 const unsigned char *p1 = (const unsigned char *) s1; |
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47 const unsigned char *p2 = (const unsigned char *) s2; |
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48 unsigned char c1, c2; |
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49 int state; |
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50 int diff; |
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51 |
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52 /* Symbol(s) 0 [1-9] others (padding) |
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53 Transition (10) 0 (01) d (00) x (11) - */ |
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54 static const unsigned int next_state[] = |
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55 { |
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56 /* state x d 0 - */ |
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57 /* S_N */ S_N, S_I, S_Z, S_N, |
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58 /* S_I */ S_N, S_I, S_I, S_I, |
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59 /* S_F */ S_N, S_F, S_F, S_F, |
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60 /* S_Z */ S_N, S_F, S_Z, S_Z |
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61 }; |
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62 |
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63 static const int result_type[] = |
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64 { |
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65 /* state x/x x/d x/0 x/- d/x d/d d/0 d/- |
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66 0/x 0/d 0/0 0/- -/x -/d -/0 -/- */ |
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67 |
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68 /* S_N */ CMP, CMP, CMP, CMP, CMP, LEN, CMP, CMP, |
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69 CMP, CMP, CMP, CMP, CMP, CMP, CMP, CMP, |
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70 /* S_I */ CMP, -1, -1, CMP, +1, LEN, LEN, CMP, |
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71 +1, LEN, LEN, CMP, CMP, CMP, CMP, CMP, |
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72 /* S_F */ CMP, CMP, CMP, CMP, CMP, LEN, CMP, CMP, |
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73 CMP, CMP, CMP, CMP, CMP, CMP, CMP, CMP, |
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74 /* S_Z */ CMP, +1, +1, CMP, -1, CMP, CMP, CMP, |
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75 -1, CMP, CMP, CMP |
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76 }; |
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77 |
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78 if (p1 == p2) |
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79 return 0; |
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80 |
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81 c1 = *p1++; |
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82 c2 = *p2++; |
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83 /* Hint: '0' is a digit too. */ |
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84 state = S_N | (c1 == '0') + (isdigit (c1) != 0); |
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85 |
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86 while ((diff = c1 - c2) == 0 && c1 != '\0') |
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87 { |
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88 state = next_state[state]; |
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89 c1 = *p1++; |
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90 c2 = *p2++; |
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91 state |= (c1 == '0') + (isdigit (c1) != 0); |
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92 } |
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93 |
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94 state = result_type[state << 2 | ((c2 == '0') + (isdigit (c2) != 0))]; |
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95 |
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96 switch (state) |
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97 { |
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98 case CMP: |
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99 return diff; |
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100 |
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101 case LEN: |
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102 while (isdigit (*p1++)) |
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103 if (!isdigit (*p2++)) |
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104 return 1; |
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105 |
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106 return isdigit (*p2) ? -1 : diff; |
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107 |
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108 default: |
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109 return state; |
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110 } |
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111 } |
