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-François 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 Lesser General Public |
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8 | License as published by the Free Software Foundation; either |
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9 | version 2.1 of the 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 | Lesser 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 Lesser General Public |
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17 | License along with the GNU C Library; if not, write to the Free |
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18 | Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA |
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19 | 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 | #include <machine/weakalias.h> |
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24 | |
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25 | /* states: S_N: normal, S_I: comparing integral part, S_F: comparing |
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26 | fractionnal parts, S_Z: idem but with leading Zeroes only */ |
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27 | #define S_N 0x0 |
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28 | #define S_I 0x4 |
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29 | #define S_F 0x8 |
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30 | #define S_Z 0xC |
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31 | |
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32 | /* result_type: CMP: return diff; LEN: compare using len_diff/diff */ |
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33 | #define CMP 2 |
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34 | #define LEN 3 |
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35 | |
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36 | |
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37 | /* Compare S1 and S2 as strings holding indices/version numbers, |
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38 | returning less than, equal to or greater than zero if S1 is less than, |
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39 | equal to or greater than S2 (for more info, see the texinfo doc). |
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40 | */ |
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41 | |
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42 | int |
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43 | __strverscmp (s1, s2) |
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44 | const char *s1; |
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45 | const char *s2; |
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46 | { |
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47 | const unsigned char *p1 = (const unsigned char *) s1; |
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48 | const unsigned char *p2 = (const unsigned char *) s2; |
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49 | unsigned char c1, c2; |
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50 | int state; |
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51 | int diff; |
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52 | |
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53 | /* Symbol(s) 0 [1-9] others (padding) |
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54 | Transition (10) 0 (01) d (00) x (11) - */ |
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55 | static const unsigned int next_state[] = |
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56 | { |
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57 | /* state x d 0 - */ |
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58 | /* S_N */ S_N, S_I, S_Z, S_N, |
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59 | /* S_I */ S_N, S_I, S_I, S_I, |
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60 | /* S_F */ S_N, S_F, S_F, S_F, |
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61 | /* S_Z */ S_N, S_F, S_Z, S_Z |
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62 | }; |
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63 | |
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64 | static const int result_type[] = |
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65 | { |
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66 | /* state x/x x/d x/0 x/- d/x d/d d/0 d/- |
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67 | 0/x 0/d 0/0 0/- -/x -/d -/0 -/- */ |
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68 | |
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69 | /* S_N */ CMP, CMP, CMP, CMP, CMP, LEN, CMP, CMP, |
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70 | CMP, CMP, CMP, CMP, CMP, CMP, CMP, CMP, |
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71 | /* S_I */ CMP, -1, -1, CMP, +1, LEN, LEN, CMP, |
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72 | +1, LEN, LEN, CMP, CMP, CMP, CMP, CMP, |
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73 | /* S_F */ CMP, CMP, CMP, CMP, CMP, LEN, CMP, CMP, |
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74 | CMP, CMP, CMP, CMP, CMP, CMP, CMP, CMP, |
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75 | /* S_Z */ CMP, +1, +1, CMP, -1, CMP, CMP, CMP, |
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76 | -1, CMP, CMP, CMP |
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77 | }; |
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78 | |
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79 | if (p1 == p2) |
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80 | return 0; |
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81 | |
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82 | c1 = *p1++; |
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83 | c2 = *p2++; |
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84 | /* Hint: '0' is a digit too. */ |
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85 | state = S_N | ((c1 == '0') + (isdigit (c1) != 0)); |
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86 | |
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87 | while ((diff = c1 - c2) == 0 && c1 != '\0') |
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88 | { |
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89 | state = next_state[state]; |
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90 | c1 = *p1++; |
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91 | c2 = *p2++; |
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92 | state |= (c1 == '0') + (isdigit (c1) != 0); |
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93 | } |
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94 | |
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95 | state = result_type[state << 2 | (((c2 == '0') + (isdigit (c2) != 0)))]; |
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96 | |
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97 | switch (state) |
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98 | { |
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99 | case CMP: |
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100 | return diff; |
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101 | |
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102 | case LEN: |
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103 | while (isdigit (*p1++)) |
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104 | if (!isdigit (*p2++)) |
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105 | return 1; |
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106 | |
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107 | return isdigit (*p2) ? -1 : diff; |
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108 | |
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109 | default: |
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110 | return state; |
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111 | } |
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112 | } |
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113 | weak_alias (__strverscmp, strverscmp) |
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