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#define _GNU_SOURCE
#include <ctype.h>
#include <string.h>
int strverscmp(const char *l0, const char *r0)
{
const unsigned char *l = (const void *)l0;
const unsigned char *r = (const void *)r0;
size_t i, dp, j;
int z = 1;
/* Find maximal matching prefix and track its maximal digit
* suffix and whether those digits are all zeros. */
for (dp=i=0; l[i]==r[i]; i++) {
int c = l[i];
if (!c) return 0;
if (!isdigit(c)) dp=i+1, z=1;
else if (c!='0') z=0;
}
if (l[dp]-'1'<9U && r[dp]-'1'<9U) {
/* If we're looking at non-degenerate digit sequences starting
* with nonzero digits, longest digit string is greater. */
for (j=i; isdigit(l[j]); j++)
if (!isdigit(r[j])) return 1;
if (isdigit(r[j])) return -1;
} else if (z && dp<i && (isdigit(l[i]) || isdigit(r[i]))) {
/* Otherwise, if common prefix of digit sequence is
* all zeros, digits order less than non-digits. */
return (unsigned char)(l[i]-'0') - (unsigned char)(r[i]-'0');
}
return l[i] - r[i];
}
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