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94 lines
3.6 KiB
C
94 lines
3.6 KiB
C
/* Compare file names containing version numbers.
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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) 2008-2024 Free Software Foundation, Inc.
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This file is free software: you can redistribute it and/or modify
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it under the terms of the GNU Lesser General Public License as
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published by the Free Software Foundation, either version 3 of the
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License, or (at your option) any later version.
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This file 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 Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with this program. If not, see <https://www.gnu.org/licenses/>. */
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#ifndef FILEVERCMP_H
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#define FILEVERCMP_H
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/* This file uses _GL_ATTRIBUTE_PURE. */
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#if !_GL_CONFIG_H_INCLUDED
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#error "Please include config.h first."
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#endif
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#include <stddef.h>
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#ifdef __cplusplus
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extern "C" {
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#endif
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/* Compare strings A and B as file names containing version numbers,
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and return an integer that is negative, zero, or positive depending
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on whether A compares less than, equal to, or greater than B.
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Use the following version sort algorithm:
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1. Compare the strings' maximal-length non-digit prefixes lexically.
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If there is a difference return that difference.
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Otherwise discard the prefixes and continue with the next step.
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2. Compare the strings' maximal-length digit prefixes, using
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numeric comparison of the numbers represented by each prefix.
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(Treat an empty prefix as zero; this can happen only at string end.)
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If there is a difference, return that difference.
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Otherwise discard the prefixes and continue with the next step.
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3. If both strings are empty, return 0. Otherwise continue with step 1.
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In version sort, lexical comparison is left to right, byte by byte,
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using the byte's numeric value (0-255), except that:
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1. ASCII letters sort before other bytes.
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2. A tilde sorts before anything, even an empty string.
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In addition to the version sort rules, the following strings have
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special priority and sort before all other strings (listed in order):
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1. The empty string.
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2. ".".
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3. "..".
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4. Strings starting with "." sort before other strings.
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Before comparing two strings where both begin with non-".",
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or where both begin with "." but neither is "." or "..",
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suffixes matching the C-locale extended regular expression
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(\.[A-Za-z~][A-Za-z0-9~]*)*$ are removed and the strings compared
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without them, using version sort without special priority;
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if they do not compare equal, this comparison result is used and
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the suffixes are effectively ignored. Otherwise, the entire
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strings are compared using version sort. When removing a suffix
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from a nonempty string, remove the maximal-length suffix such that
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the remaining string is nonempty.
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This function is intended to be a replacement for strverscmp. */
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int filevercmp (char const *a, char const *b) _GL_ATTRIBUTE_PURE;
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/* Like filevercmp, except compare the byte arrays A (of length ALEN)
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and B (of length BLEN) so that A and B can contain '\0', which
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sorts just before '\1'. But if ALEN is -1 treat A as a string
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terminated by '\0', and similarly for BLEN. */
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int filenvercmp (char const *a, ptrdiff_t alen, char const *b, ptrdiff_t blen)
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_GL_ATTRIBUTE_PURE;
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#ifdef __cplusplus
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}
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#endif
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#endif /* FILEVERCMP_H */
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