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Copyright (C) 1995 Ian Jackson <iwj10@cus.cam.ac.uk>
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Copyright (C) 2001 Anthony Towns <aj@azure.humbug.org.au>
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Copyright (C) 2008 Free Software Foundation, Inc.
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This program is free software: you can redistribute it and/or modify
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it under the terms of the GNU General Public License as published by
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the Free Software Foundation, either version 3 of the License, or
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(at your option) any later version.
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This program is distributed in the hope that it will be useful,
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but WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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GNU General Public License for more details.
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You should have received a copy of the GNU General Public License
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along with this program. If not, see <http://www.gnu.org/licenses/>. */
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#include "filevercmp.h"
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#include <sys/types.h>
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/* Match a file suffix defined by this regular expression:
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/(\.[A-Za-z][A-Za-z0-9]*)*$/
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Scan the string *STR and return a pointer to the matching suffix, or
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NULL if not found. Upon return, *STR points to terminating NUL. */
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match_suffix (const char **str)
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const char *match = NULL;
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bool read_alpha = false;
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if (!c_isalpha (**str))
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else if ('.' == **str)
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else if (!c_isalnum (**str))
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/* verrevcmp helper function */
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order (unsigned char c)
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else if (c_isalpha (c))
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return (int) c + UCHAR_MAX + 1;
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/* slightly modified verrevcmp function from dpkg
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S1, S2 - compared string
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S1_LEN, S2_LEN - length of strings to be scanned
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This implements the algorithm for comparison of version strings
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specified by Debian and now widely adopted. The detailed
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specification can be found in the Debian Policy Manual in the
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section on the `Version' control field. This version of the code
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implements that from s5.6.12 of Debian Policy v3.8.0.1
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http://www.debian.org/doc/debian-policy/ch-controlfields.html#s-f-Version */
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verrevcmp (const char *s1, size_t s1_len, const char *s2, size_t s2_len)
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while (s1_pos < s1_len || s2_pos < s2_len)
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while ((s1_pos < s1_len && !c_isdigit (s1[s1_pos]))
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|| (s2_pos < s2_len && !c_isdigit (s2[s2_pos])))
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int s1_c = (s1_pos == s1_len) ? 0 : order (s1[s1_pos]);
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int s2_c = (s2_pos == s2_len) ? 0 : order (s2[s2_pos]);
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while (s1[s1_pos] == '0')
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while (s2[s2_pos] == '0')
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while (c_isdigit (s1[s1_pos]) && c_isdigit (s2[s2_pos]))
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first_diff = s1[s1_pos] - s2[s2_pos];
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if (c_isdigit (s1[s1_pos]))
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if (c_isdigit (s2[s2_pos]))
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/* Compare version strings S1 and S2.
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See filevercmp.h for function description. */
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filevercmp (const char *s1, const char *s2)
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const char *s1_pos = s1;
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const char *s2_pos = s2;
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const char *s1_suffix, *s2_suffix;
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size_t s1_len, s2_len;
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/* easy comparison to see if strings are identical */
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int simple_cmp = strcmp (s1, s2);
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/* "cut" file suffixes */
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s1_suffix = match_suffix (&s1_pos);
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s2_suffix = match_suffix (&s2_pos);
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s1_len = (s1_suffix ? s1_suffix : s1_pos) - s1;
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s2_len = (s2_suffix ? s2_suffix : s2_pos) - s2;
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/* restore file suffixes if strings are identical after "cut" */
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if ((s1_suffix || s2_suffix) && (s1_len == s2_len)
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&& 0 == strncmp (s1, s2, s1_len))
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s1_len = s1_pos - s1;
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s2_len = s2_pos - s2;
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result = verrevcmp (s1, s1_len, s2, s2_len);
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return result == 0 ? simple_cmp : result;