100 lines
2.9 KiB
C
100 lines
2.9 KiB
C
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/*
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FUNCTION
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<<strverscmp>>---version string compare
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INDEX
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strverscmp
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ANSI_SYNOPSIS
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#define _GNU_SOURCE
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#include <string.h>
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int strverscmp(const char *<[a]>, const char *<[b]>);
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TRAD_SYNOPSIS
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#define _GNU_SOURCE
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#include <string.h>
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int strverscmp(<[a]>, <[b]>)
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char *<[a]>;
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char *<[b]>;
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DESCRIPTION
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<<strverscmp>> compares the string at <[a]> to
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the string at <[b]> in a version-logical order.
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RETURNS
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If <<*<[a]>>> version-sorts after <<*<[b]>>>, <<strverscmp>> returns
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a number greater than zero. If the two strings match, <<strverscmp>>
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returns zero. If <<*<[a]>>> version-sorts before <<*<[b]>>>,
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<<strverscmp>> returns a number less than zero.
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PORTABILITY
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<<strverscmp>> is a GNU extension.
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<<strverscmp>> requires no supporting OS subroutines. It uses
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isdigit() from elsewhere in this library.
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QUICKREF
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strverscmp
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*/
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/*
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From musl src/string/strverscmp.c
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Copyright © 2005-2014 Rich Felker, et al.
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Permission is hereby granted, free of charge, to any person obtaining
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a copy of this software and associated documentation files (the
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"Software"), to deal in the Software without restriction, including
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without limitation the rights to use, copy, modify, merge, publish,
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distribute, sublicense, and/or sell copies of the Software, and to
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permit persons to whom the Software is furnished to do so, subject to
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the following conditions:
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The above copyright notice and this permission notice shall be
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included in all copies or substantial portions of the Software.
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THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
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IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
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CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
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TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
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SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
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*/
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#define _GNU_SOURCE
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#include <ctype.h>
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#include <string.h>
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int strverscmp(const char *l0, const char *r0)
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{
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const unsigned char *l = (const void *)l0;
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const unsigned char *r = (const void *)r0;
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size_t i, dp, j;
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int z = 1;
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/* Find maximal matching prefix and track its maximal digit
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* suffix and whether those digits are all zeros. */
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for (dp=i=0; l[i]==r[i]; i++) {
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int c = l[i];
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if (!c) return 0;
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if (!isdigit(c)) dp=i+1, z=1;
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else if (c!='0') z=0;
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}
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if (l[dp]!='0' && r[dp]!='0') {
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/* If we're not looking at a digit sequence that began
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* with a zero, longest digit string is greater. */
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for (j=i; isdigit(l[j]); j++)
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if (!isdigit(r[j])) return 1;
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if (isdigit(r[j])) return -1;
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} else if (z && dp<i && (isdigit(l[i]) || isdigit(r[i]))) {
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/* Otherwise, if common prefix of digit sequence is
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* all zeros, digits order less than non-digits. */
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return (unsigned char)(l[i]-'0') - (unsigned char)(r[i]-'0');
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}
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return l[i] - r[i];
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}
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