/** \ingroup rpmts

 * \file lib/rpmvercmp.c

 */

#include "system.h"

#include <rpm/rpmlib.h>		/* rpmvercmp proto */

#include <rpm/rpmstring.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)

{

    /* easy comparison to see if versions are identical */

    if (rstreq(a, b)) return 0;

    char oldch1, oldch2;

    char abuf[strlen(a)+1], bbuf[strlen(b)+1];

    char *str1 = abuf, *str2 = bbuf;

    char * one, * two;

    int rc;

    int isnum;

    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 && !risalnum(*one) && *one != '~') one++;

	while (*two && !risalnum(*two) && *two != '~') two++;

	/* handle the tilde separator, it sorts before everything else */

	if (*one == '~' || *two == '~') {

	    if (*one != '~') return 1;

	    if (*two != '~') return -1;

	    one++;

	    two++;

	    continue;

	}

	/* If we ran to the end of either, we are finished with the loop */

	if (!(*one && *two)) break;

	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 (risdigit(*str1)) {

	    while (*str1 && risdigit(*str1)) str1++;

	    while (*str2 && risdigit(*str2)) str2++;

	    isnum = 1;

	} else {

	    while (*str1 && risalpha(*str1)) str1++;

	    while (*str2 && risalpha(*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';

	/* this cannot happen, as we previously tested to make sure that */

	/* the first string has a non-null segment */

	if (one == str1) return -1;	/* arbitrary */

	/* take care of the case where the two version segments are */

	/* different types: one numeric, the other alpha (i.e. empty) */

	/* numeric segments are always newer than alpha segments */

	/* XXX See patch #60884 (and details) from bugzilla #50977. */

	if (two == str2) return (isnum ? 1 : -1);

	if (isnum) {

	    size_t onelen, twolen;

	    /* 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 */

	    onelen = strlen(one);

	    twolen = strlen(two);

	    if (onelen > twolen) return 1;

	    if (twolen > onelen) 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 */

	*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;

}

int rpmVersionCompare(Header first, Header second)

{

    /* Missing epoch becomes zero here, which is what we want */

    uint32_t epochOne = headerGetNumber(first, RPMTAG_EPOCH);

    uint32_t epochTwo = headerGetNumber(second, RPMTAG_EPOCH);

    int rc;

    if (epochOne < epochTwo)

	return -1;

    else if (epochOne > epochTwo)

	return 1;

    rc = rpmvercmp(headerGetString(first, RPMTAG_VERSION),

		   headerGetString(second, RPMTAG_VERSION));

    if (rc)

	return rc;

    return rpmvercmp(headerGetString(first, RPMTAG_RELEASE),

		     headerGetString(second, RPMTAG_RELEASE));

}