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/** \ingroup rpmtrans
* \file lib/rpmvercmp.c
*/
#include "system.h"
#include <rpmio.h>
#include "debug.h"
/* compare alpha and numeric segments of two versions */
/* return 1: a is newer than b */
/* 0: a and b are the same version */
/* -1: b is newer than a */
int rpmvercmp(const char * a, const char * b)
{
char oldch1, oldch2;
char * str1, * str2;
char * one, * two;
int rc;
int isnum;
/* easy comparison to see if versions are identical */
if (!strcmp(a, b)) return 0;
str1 = alloca(strlen(a) + 1);
str2 = alloca(strlen(b) + 1);
strcpy(str1, a);
strcpy(str2, b);
one = str1;
two = str2;
/* loop through each version segment of str1 and str2 and compare them */
while (*one && *two) {
while (*one && !xisalnum(*one)) one++;
while (*two && !xisalnum(*two)) two++;
str1 = one;
str2 = two;
/* grab first completely alpha or completely numeric segment */
/* leave one and two pointing to the start of the alpha or numeric */
/* segment and walk str1 and str2 to end of segment */
if (xisdigit(*str1)) {
while (*str1 && xisdigit(*str1)) str1++;
while (*str2 && xisdigit(*str2)) str2++;
isnum = 1;
} else {
while (*str1 && xisalpha(*str1)) str1++;
while (*str2 && xisalpha(*str2)) str2++;
isnum = 0;
}
/* save character at the end of the alpha or numeric segment */
/* so that they can be restored after the comparison */
oldch1 = *str1;
*str1 = '\0';
oldch2 = *str2;
*str2 = '\0';
/* take care of the case where the two version segments are */
/* different types: one numeric, the other alpha (i.e. empty) */
if (one == str1) return -1; /* arbitrary */
if (two == str2) return 1;
if (isnum) {
/* this used to be done by converting the digit segments */
/* to ints using atoi() - it's changed because long */
/* digit segments can overflow an int - this should fix that. */
/* throw away any leading zeros - it's a number, right? */
while (*one == '0') one++;
while (*two == '0') two++;
/* whichever number has more digits wins */
if (strlen(one) > strlen(two)) return 1;
if (strlen(two) > strlen(one)) return -1;
}
/* strcmp will return which one is greater - even if the two */
/* segments are alpha or if they are numeric. don't return */
/* if they are equal because there might be more segments to */
/* compare */
rc = strcmp(one, two);
if (rc) return rc;
/* restore character that was replaced by null above */
*str1 = oldch1;
one = str1;
*str2 = oldch2;
two = str2;
}
/* this catches the case where all numeric and alpha segments have */
/* compared identically but the segment sepparating characters were */
/* different */
if ((!*one) && (!*two)) return 0;
/* whichever version still has characters left over wins */
if (!*one) return -1; else return 1;
}
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