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# rpmvercmp.c

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    00001
    00005 #include "system.h"
    00006
    00007 #include <rpmlib.h>
    00008
    00009 #include "debug.h"
    00010
    00011 /* compare alpha and numeric segments of two versions */
    00012 /* return 1: a is newer than b */
    00013 /*        0: a and b are the same version */
    00014 /*       -1: b is newer than a */
    00015 int rpmvercmp(const char * a, const char * b)
    00016 {
    00017     char oldch1, oldch2;
    00018     char * str1, * str2;
    00019     char * one, * two;
    00020     int rc;
    00021     int isnum;
    00022
    00023     /* easy comparison to see if versions are identical */
    00024     if (!strcmp(a, b)) return 0;
    00025
    00026     str1 = alloca(strlen(a) + 1);
    00027     str2 = alloca(strlen(b) + 1);
    00028
    00029     strcpy(str1, a);
    00030     strcpy(str2, b);
    00031
    00032     one = str1;
    00033     two = str2;
    00034
    00035     /* loop through each version segment of str1 and str2 and compare them */
    00036     while (*one && *two) {
    00037         while (*one && !xisalnum(*one)) one++;
    00038         while (*two && !xisalnum(*two)) two++;
    00039
    00040         str1 = one;
    00041         str2 = two;
    00042
    00043         /* grab first completely alpha or completely numeric segment */
    00044         /* leave one and two pointing to the start of the alpha or numeric */
    00045         /* segment and walk str1 and str2 to end of segment */
    00046         if (xisdigit(*str1)) {
    00047             while (*str1 && xisdigit(*str1)) str1++;
    00048             while (*str2 && xisdigit(*str2)) str2++;
    00049             isnum = 1;
    00050         } else {
    00051             while (*str1 && xisalpha(*str1)) str1++;
    00052             while (*str2 && xisalpha(*str2)) str2++;
    00053             isnum = 0;
    00054         }
    00055
    00056         /* save character at the end of the alpha or numeric segment */
    00057         /* so that they can be restored after the comparison */
    00058         oldch1 = *str1;
    00059         *str1 = '\0';
    00060         oldch2 = *str2;
    00061         *str2 = '\0';
    00062
    00063         /* take care of the case where the two version segments are */
    00064         /* different types: one numeric, the other alpha (i.e. empty) */
    00065         if (one == str1) return -1;     /* arbitrary */
    00066         if (two == str2) return -1;
    00067
    00068         if (isnum) {
    00069             /* this used to be done by converting the digit segments */
    00070             /* to ints using atoi() - it's changed because long  */
    00071             /* digit segments can overflow an int - this should fix that. */
    00072
    00073             /* throw away any leading zeros - it's a number, right? */
    00074             while (*one == '0') one++;
    00075             while (*two == '0') two++;
    00076
    00077             /* whichever number has more digits wins */
    00078             if (strlen(one) > strlen(two)) return 1;
    00079             if (strlen(two) > strlen(one)) return -1;
    00080         }
    00081
    00082         /* strcmp will return which one is greater - even if the two */
    00083         /* segments are alpha or if they are numeric.  don't return  */
    00084         /* if they are equal because there might be more segments to */
    00085         /* compare */
    00086         rc = strcmp(one, two);
    00087         if (rc) return rc;
    00088
    00089         /* restore character that was replaced by null above */
    00090         *str1 = oldch1;
    00091         one = str1;
    00092         *str2 = oldch2;
    00093         two = str2;
    00094     }
    00095
    00096     /* this catches the case where all numeric and alpha segments have */
    00097     /* compared identically but the segment sepparating characters were */
    00098     /* different */
    00099     if ((!*one) && (!*two)) return 0;
    00100
    00101     /* whichever version still has characters left over wins */
    00102     if (!*one) return -1; else return 1;
    00103 }