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Diffstat (limited to 'lib/strutil/filevercmp.c')
| -rw-r--r-- | lib/strutil/filevercmp.c | 265 |
1 files changed, 265 insertions, 0 deletions
diff --git a/lib/strutil/filevercmp.c b/lib/strutil/filevercmp.c new file mode 100644 index 0000000..a0e55fc --- /dev/null +++ b/lib/strutil/filevercmp.c @@ -0,0 +1,265 @@ +/* + Copyright (C) 1995 Ian Jackson <iwj10@cus.cam.ac.uk> + Copyright (C) 2001 Anthony Towns <aj@azure.humbug.org.au> + Copyright (C) 2008-2022 Free Software Foundation, Inc. + + This file is free software: you can redistribute it and/or modify + it under the terms of the GNU Lesser General Public License as + published by the Free Software Foundation, either version 3 of the + License, or (at your option) any later version. + + This file is distributed in the hope that it will be useful, + but WITHOUT ANY WARRANTY; without even the implied warranty of + MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + GNU Lesser General Public License for more details. + + You should have received a copy of the GNU Lesser General Public License + along with this program. If not, see <https://www.gnu.org/licenses/>. + */ + +#include <config.h> + +#include <stdlib.h> +#include <limits.h> + +#include "lib/strutil.h" + +/*** global variables ****************************************************************************/ + +/*** file scope macro definitions ****************************************************************/ + +/*** file scope type declarations ****************************************************************/ + +/*** file scope variables ************************************************************************/ + +/* --------------------------------------------------------------------------------------------- */ +/*** file scope functions ************************************************************************/ +/* --------------------------------------------------------------------------------------------- */ + +/* Return the length of a prefix of @s that corresponds to the suffix defined by this extended + * regular expression in the C locale: (\.[A-Za-z~][A-Za-z0-9~]*)*$ + * + * Use the longest suffix matching this regular expression, except do not use all of s as a suffix + * if s is nonempty. + * + * If *len is -1, s is a string; set *lem to s's length. + * Otherwise, *len should be nonnegative, s is a char array, and *len does not change. + */ +static ssize_t +file_prefixlen (const char *s, ssize_t * len) +{ + size_t n = (size_t) (*len); /* SIZE_MAX if N == -1 */ + size_t i = 0; + size_t prefixlen = 0; + + while (TRUE) + { + gboolean done; + + if (*len < 0) + done = s[i] == '\0'; + else + done = i == n; + + if (done) + { + *len = (ssize_t) i; + return (ssize_t) prefixlen; + } + + i++; + prefixlen = i; + + while (i + 1 < n && s[i] == '.' && (g_ascii_isalpha (s[i + 1]) || s[i + 1] == '~')) + for (i += 2; i < n && (g_ascii_isalnum (s[i]) || s[i] == '~'); i++) + ; + } +} + +/* --------------------------------------------------------------------------------------------- */ + +/* Return a version sort comparison value for @s's byte at position @pos. + * + * @param s a string + * @param pos a position in @s + * @param len a length of @s. If @pos == @len, sort before all non-'~' bytes. + */ + +static int +order (const char *s, size_t pos, size_t len) +{ + unsigned char c; + + if (pos == len) + return (-1); + + c = s[pos]; + + if (g_ascii_isdigit (c)) + return 0; + if (g_ascii_isalpha (c)) + return c; + if (c == '~') + return (-2); + + g_assert (UCHAR_MAX <= (INT_MAX - 1 - 2) / 2); + + return (int) c + UCHAR_MAX + 1; +} + +/* --------------------------------------------------------------------------------------------- */ + +/* Slightly modified verrevcmp function from dpkg + * + * This implements the algorithm for comparison of version strings + * specified by Debian and now widely adopted. The detailed + * specification can be found in the Debian Policy Manual in the + * section on the 'Version' control field. This version of the code + * implements that from s5.6.12 of Debian Policy v3.8.0.1 + * https://www.debian.org/doc/debian-policy/ch-controlfields.html#s-f-Version + * + * @param s1 first char array to compare + * @param s1_len length of @s1 + * @param s2 second char array to compare + * @param s2_len length of @s2 + * + * @return an integer less than, equal to, or greater than zero, if @s1 is <, == or > than @s2. + */ +static int +verrevcmp (const char *s1, ssize_t s1_len, const char *s2, ssize_t s2_len) +{ + ssize_t s1_pos = 0; + ssize_t s2_pos = 0; + + while (s1_pos < s1_len || s2_pos < s2_len) + { + int first_diff = 0; + + while ((s1_pos < s1_len && !g_ascii_isdigit (s1[s1_pos])) + || (s2_pos < s2_len && !g_ascii_isdigit (s2[s2_pos]))) + { + int s1_c, s2_c; + + s1_c = order (s1, s1_pos, s1_len); + s2_c = order (s2, s2_pos, s2_len); + + if (s1_c != s2_c) + return (s1_c - s2_c); + + s1_pos++; + s2_pos++; + } + + while (s1_pos < s1_len && s1[s1_pos] == '0') + s1_pos++; + while (s2_pos < s2_len && s2[s2_pos] == '0') + s2_pos++; + + while (s1_pos < s1_len && s2_pos < s2_len + && g_ascii_isdigit (s1[s1_pos]) && g_ascii_isdigit (s2[s2_pos])) + { + if (first_diff == 0) + first_diff = s1[s1_pos] - s2[s2_pos]; + + s1_pos++; + s2_pos++; + } + + if (s1_pos < s1_len && g_ascii_isdigit (s1[s1_pos])) + return 1; + if (s2_pos < s2_len && g_ascii_isdigit (s2[s2_pos])) + return (-1); + if (first_diff != 0) + return first_diff; + } + + return 0; +} + +/* --------------------------------------------------------------------------------------------- */ +/*** public functions ****************************************************************************/ +/* --------------------------------------------------------------------------------------------- */ + +/* Compare version strings. + * + * @param s1 first string to compare + * @param s2 second string to compare + * + * @return an integer less than, equal to, or greater than zero, if @s1 is <, == or > than @s2. + */ +int +filevercmp (const char *s1, const char *s2) +{ + return filenvercmp (s1, -1, s2, -1); +} + +/* --------------------------------------------------------------------------------------------- */ +/* Compare version strings. + * + * @param a first string to compare + * @param alen length of @a or (-1) + * @param b second string to compare + * @param blen length of @b or (-1) + * + * @return an integer less than, equal to, or greater than zero, if @s1 is <, == or > than @s2. + */ +int +filenvercmp (const char *a, ssize_t alen, const char *b, ssize_t blen) +{ + gboolean aempty, bempty; + ssize_t aprefixlen, bprefixlen; + gboolean one_pass_only; + int result; + + /* Special case for empty versions. */ + aempty = alen < 0 ? a[0] == '\0' : alen == 0; + bempty = blen < 0 ? b[0] == '\0' : blen == 0; + + if (aempty) + return (bempty ? 0 : -1); + if (bempty) + return 1; + + /* Special cases for leading ".": "." sorts first, then "..", then other names with leading ".", + then other names. */ + if (a[0] == '.') + { + gboolean adot, bdot; + gboolean adotdot, bdotdot; + + if (b[0] != '.') + return (-1); + + adot = alen < 0 ? a[1] == '\0' : alen == 1; + bdot = blen < 0 ? b[1] == '\0' : blen == 1; + + if (adot) + return (bdot ? 0 : -1); + if (bdot) + return 1; + + adotdot = a[1] == '.' && (alen < 0 ? a[2] == '\0' : alen == 2); + bdotdot = b[1] == '.' && (blen < 0 ? b[2] == '\0' : blen == 2); + if (adotdot) + return (bdotdot ? 0 : -1); + if (bdotdot) + return 1; + } + else if (b[0] == '.') + return 1; + + /* Cut file suffixes. */ + aprefixlen = file_prefixlen (a, &alen); + bprefixlen = file_prefixlen (b, &blen); + + /* If both suffixes are empty, a second pass would return the same thing. */ + one_pass_only = aprefixlen == alen && bprefixlen == blen; + + result = verrevcmp (a, aprefixlen, b, bprefixlen); + + /* Return the initial result if nonzero, or if no second pass is needed. + Otherwise, restore the suffixes and try again. */ + return (result != 0 || one_pass_only ? result : verrevcmp (a, alen, b, blen)); +} + +/* --------------------------------------------------------------------------------------------- */ |