/*
 * @(#)version_comp.c	1.10 06/02/25
 *
 * Copyright 2006 Sun Microsystems, Inc. All rights reserved.
 * SUN PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 */

#include <ctype.h>
#include <stdlib.h>
#include <string.h>
#include <sys/types.h>
#include "jni.h"
#include "jli_util.h"
#include "version_comp.h"

/*
 *	A collection of useful strings. One should think of these as #define
 *	entries, but actual strings can be more efficient (with many compilers).
 */
static const char *separators	= ".-_";
static const char *zero_string	= "0";

/*
 *	Validate a string as parsable as a "Java int". If so parsable,
 *	return true (non-zero) and store the numeric value at the address
 *	passed in as "value"; otherwise return false (zero).
 *
 *	Note that the maximum allowable value is 2147483647 as defined by
 *	the "Java Language Specification" which precludes the use of native
 *	conversion routines which may have other limits.
 *
 *	Also note that we don't have to worry about the alternate maximum
 *	allowable value of 2147483648 because it is only allowed after
 *	the unary negation operator and this grammar doesn't have one
 *	of those.
 *
 *	Finally, note that a value which exceeds the maximum jint value will
 *	return false (zero). This results in the otherwise purely numeric
 *	string being compared as a string of characters (as per the spec.)
 */
static int
isjavaint(const char *s, jint *value)
{
    jlong sum = 0;
    jint digit;
    while (*s != '\0')
	if (isdigit(*s)) {
	    digit = (jint)((int)(*s++) - (int)('0'));
	    sum = (sum * 10) + digit;
	    if (sum > 2147483647)
		return (0);	/* Overflows jint (but not jlong) */
	} else
	    return (0);
    *value = (jint)sum;
    return (1);
}

/*
 *	Modeled after strcmp(), compare two strings (as in the grammar defined
 *	in Appendix A of JSR 56).  If both strings can be interpreted as
 *	Java ints, do a numeric comparison, else it is strcmp().
 */
static int
comp_string(const char *s1, const char *s2)
{
    jint v1, v2;
    if (isjavaint(s1, &v1) && isjavaint(s2, &v2))
	return ((int)(v1 - v2));
    else
	return (strcmp(s1, s2));
}

/*
 *	Modeled after strcmp(), compare two version-ids for a Prefix
 *	Match as defined in JSR 56.
 */
int
JLI_PrefixVersionId(char *id1, char *id2)
{
    char	*s1 = JLI_StringDup(id1);
    char	*s2 = JLI_StringDup(id2);
    char	*m1 = s1;
    char	*m2 = s2;
    char	*end1 = NULL;
    char	*end2 = NULL;
    int	res = 0;

    do {

	if ((s1 != NULL) && ((end1 = strpbrk(s1, ".-_")) != NULL))
	    *end1 = '\0';
	if ((s2 != NULL) && ((end2 = strpbrk(s2, ".-_")) != NULL))
	    *end2 = '\0';

	res = comp_string(s1, s2);

	if (end1 != NULL)
	    s1 = end1 + 1;
	else
	    s1 = NULL;