On Wed, Apr 11, 2007 at 09:01:33AM +0200, Mark wrote:
> would this work?
You just have to do what rpm does, whatever your implementation
language is. I join what rpm does. I think that code is under the
GPL (it's directly part of the rpm source in any case, check there if
you want to see the license).
Incidentally, the version comparison is not the worse part by far.
It's the file dependencies that are the real bitch.
OG.
/** \ingroup rpmts
* \file lib/rpmvercmp.c
*/
#include <string.h>
#include <ctype.h>
#include <alloca.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 */
/*@-branchstate@*/
/*@-boundsread@*/
while (*one && *two) {
while (*one && !isalnum(*one)) one++;
while (*two && !isalnum(*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 (isdigit(*str1)) {
while (*str1 && isdigit(*str1)) str1++;
while (*str2 && isdigit(*str2)) str2++;
isnum = 1;
} else {
while (*str1 && isalpha(*str1)) str1++;
while (*str2 && isalpha(*str2)) str2++;
isnum = 0;
}
/* save character at the end of the alpha or numeric segment */
/* so that they can be restored after the comparison */
/*@-boundswrite@*/
oldch1 = *str1;
*str1 = '\0';
oldch2 = *str2;
*str2 = '\0';
/*@=boundswrite@*/
/* 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 */
/* XXX See patch #60884 (and details) from bugzilla #50977. */
if (two == str2) return (isnum ? 1 : -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 < 1 ? -1 : 1);
/* restore character that was replaced by null above */
/*@-boundswrite@*/
*str1 = oldch1;
one = str1;
*str2 = oldch2;
two = str2;
/*@=boundswrite@*/
}
/*@=branchstate@*/
/*@=boundsread@*/
/* this catches the case where all numeric and alpha segments have */
/* compared identically but the segment sepparating characters were */
/* different */
/*@-boundsread@*/
if ((!*one) && (!*two)) return 0;
/* whichever version still has characters left over wins */
if (!*one) return -1; else return 1;
/*@=boundsread@*/
}
--
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