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lib/rpmvercmp.c

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#include "system.h"

#include "rpmlib.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++;

        if ( !*one && !*two )
                return 0;

        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 */
        /* Also take care of the case where the two version segments are */
        /* different types: one numeric and one alpha */
        if (xisdigit(*str1)) {
            if ( xisalpha(*str2) ) return -1;
            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;
        }

        /* Again, take care of the case where the two version segments are */
        /* different types: one numeric and one alpha */
        if (one == str1) return -1;
        if (two == str2) return 1;

        /* 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';

        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;
}

/* Moved from depends.c, because we use it in other places, too. */
void parseEVR(char * evr,
                /*@exposed@*/ /*@out@*/ const char ** ep,
                /*@exposed@*/ /*@out@*/ const char ** vp,
                /*@exposed@*/ /*@out@*/ const char ** rp)
        /*@modifies *ep, *vp, *rp @*/
{
    const char *epoch;
    const char *version;                /* assume only version is present */
    const char *release;
    char *s, *se;

    s = evr;
    while (*s && xisdigit(*s)) s++;     /* s points to epoch terminator */
    se = strrchr(s, '-');               /* se points to version terminator */

    if (*s == ':') {
        epoch = evr;
        *s++ = '\0';
        version = s;
        if (*epoch == '\0') epoch = "0";
    } else {
        epoch = NULL;   /* XXX disable epoch compare if missing */
        version = evr;
    }
    if (se) {
        *se++ = '\0';
        release = se;
    } else {
        release = NULL;
    }

    if (ep) *ep = epoch;
    if (vp) *vp = version;
    if (rp) *rp = release;
}

/* Compare {A,B} [epoch:]version[-release] */
int 
rpmEVRcmp(const char * const aE, const char * const aV, const char * const aR,
          const char * const aDepend,
          const char * const bE, const char * const bV, const char * const bR,
          const char * const bDepend)
{
    int sense = 0;

    rpmMessage(RPMMESS_DEBUG, "cmp e=%s, v=%s, r=%s\n and e=%s, v=%s, r=%s\n ",
               aE, aV, aR, bE, bV, bR);


    if (aE && *aE && bE && *bE)
        sense = rpmvercmp(aE, bE);
    else if (aE && *aE && atol(aE) > 0) {
        /* XXX legacy epoch-less requires/conflicts compatibility */
        rpmMessage(RPMMESS_DEBUG, _("the \"B\" dependency needs an epoch (assuming same as \"A\")\n\tA %s\tB %s\n"),
                aDepend, bDepend);
        sense = 0;
    } else if (bE && *bE && atol(bE) > 0)
        sense = -1;

    if (sense == 0) {
        sense = rpmvercmp(aV, bV);
        if (sense == 0 && aR && *aR && bR && *bR) {
            sense = rpmvercmp(aR, bR);
        }
    }

    return sense;
}

int isChangeNameMoreFresh(const char * const head, 
                          const char * const tail[3]) 
{
  int result;
  const char * evr[3];
  const char * wordAfterEmail;
  char * copy;

  rpmMessage(RPMMESS_DEBUG, "test: is '%s' more fresh than e=%s, v=%s, r=%s?\n",
             head, tail[0], tail[1], tail[2]);
  /* find the next to <email> word begin */
  if ( (wordAfterEmail = strrchr(head, '>')) )
    ++wordAfterEmail;
  else
    wordAfterEmail = head;
  while ( *wordAfterEmail && xisspace(*wordAfterEmail) )
    ++wordAfterEmail; 
  /* found. */
  copy = xstrdup(wordAfterEmail);
  parseEVR(copy, &evr[0],  &evr[1],  &evr[2]);
  /* The order of two argument groups is important: 
     if evr[] (passed as B on the second place) has no epoch, 
     rpmEVRcmp() assumes the same as in tail[];
     This fits our needs: the epoch may be omitted in a changelog entry (evr[])
     but there are no problems in specifying it in the format (tail[]). */
  result = rpmEVRcmp(tail[0], tail[1], tail[2], "",
                     evr[0], evr[1], evr[2], "") < 0;
  _free(copy);
  return result;
}

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