Move vercmp code into a separate file

This will facilitate using this object file on its own in the vercmp tool
which will be done in a future commit. The net impact on the generated
binaries should not be noticeable after this commit.

Signed-off-by: Dan McGee <dan@archlinux.org>

1 files changed, 198 insertions, 0 deletions

diff --git a/lib/libalpm/version.c b/lib/libalpm/version.c
new file mode 100644
index 00000000..1c838f41
--- /dev/null
+++ b/lib/libalpm/version.c
@@ -0,0 +1,198 @@
+/*
+ *  Copyright (c) 2006-2010 Pacman Development Team <pacman-dev@archlinux.org>
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License as published by
+ *  the Free Software Foundation; either version 2 of the License, or
+ *  (at your option) any later version.
+ *
+ *  This program is distributed in the hope that it will be useful,
+ *  but WITHOUT ANY WARRANTY; without even the implied warranty of
+ *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+ *  GNU General Public License for more details.
+ *
+ *  You should have received a copy of the GNU General Public License
+ *  along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#include "config.h"
+
+#include <string.h>
+#include <ctype.h>
+
+/* libalpm */
+#include "log.h"
+#include "util.h"
+
+/** Compare two version strings and determine which one is 'newer'.
+ * Returns a value comparable to the way strcmp works. Returns 1
+ * if a is newer than b, 0 if a and b are the same version, or -1
+ * if b is newer than a.
+ *
+ * This function has been adopted from the rpmvercmp function located
+ * at lib/rpmvercmp.c, and was most recently updated against rpm
+ * version 4.4.2.3. Small modifications have been made to make it more
+ * consistent with the libalpm coding style.
+ *
+ * Keep in mind that the pkgrel is only compared if it is available
+ * on both versions handed to this function. For example, comparing
+ * 1.5-1 and 1.5 will yield 0; comparing 1.5-1 and 1.5-2 will yield
+ * -1 as expected. This is mainly for supporting versioned dependencies
+ * that do not include the pkgrel.
+ */
+int SYMEXPORT alpm_pkg_vercmp(const char *a, const char *b)
+{
+	char oldch1, oldch2;
+	char *str1, *str2;
+	char *ptr1, *ptr2;
+	char *one, *two;
+	int rc;
+	int isnum;
+	int ret = 0;
+
+	ALPM_LOG_FUNC;
+
+	/* libalpm added code. ensure our strings are not null */
+	if(!a) {
+		if(!b) return(0);
+		return(-1);
+	}
+	if(!b) return(1);
+
+	/* easy comparison to see if versions are identical */
+	if(strcmp(a, b) == 0) return(0);
+
+	str1 = strdup(a);
+	str2 = strdup(b);
+
+	one = str1;
+	two = str2;
+
+	/* loop through each version segment of str1 and str2 and compare them */
+	while(*one && *two) {
+		while(*one && !isalnum((int)*one)) one++;
+		while(*two && !isalnum((int)*two)) two++;
+
+		/* If we ran to the end of either, we are finished with the loop */
+		if(!(*one && *two)) break;
+
+		ptr1 = one;
+		ptr2 = 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 ptr1 and ptr2 to end of segment */
+		if(isdigit((int)*ptr1)) {
+			while(*ptr1 && isdigit((int)*ptr1)) ptr1++;
+			while(*ptr2 && isdigit((int)*ptr2)) ptr2++;
+			isnum = 1;
+		} else {
+			while(*ptr1 && isalpha((int)*ptr1)) ptr1++;
+			while(*ptr2 && isalpha((int)*ptr2)) ptr2++;
+			isnum = 0;
+		}
+
+		/* save character at the end of the alpha or numeric segment */
+		/* so that they can be restored after the comparison */
+		oldch1 = *ptr1;
+		*ptr1 = '\0';
+		oldch2 = *ptr2;
+		*ptr2 = '\0';
+
+		/* this cannot happen, as we previously tested to make sure that */
+		/* the first string has a non-null segment */
+		if (one == ptr1) {
+			ret = -1;	/* arbitrary */
+			goto cleanup;
+		}
+
+		/* 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 == ptr2) {
+			ret = isnum ? 1 : -1;
+			goto cleanup;
+		}
+
+		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)) {
+				ret = 1;
+				goto cleanup;
+			}
+			if (strlen(two) > strlen(one)) {
+				ret = -1;
+				goto cleanup;
+			}
+		}
+
+		/* 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) {
+			ret = rc < 1 ? -1 : 1;
+			goto cleanup;
+		}
+
+		/* restore character that was replaced by null above */
+		*ptr1 = oldch1;
+		one = ptr1;
+		*ptr2 = oldch2;
+		two = ptr2;
+
+		/* libalpm added code. check if version strings have hit the pkgrel
+		 * portion. depending on which strings have hit, take correct action.
+		 * this is all based on the premise that we only have one dash in
+		 * the version string, and it separates pkgver from pkgrel. */
+		if(*ptr1 == '-' && *ptr2 == '-') {
+			/* no-op, continue comparing since we are equivalent throughout */
+		} else if(*ptr1 == '-') {
+			/* ptr1 has hit the pkgrel and ptr2 has not. continue version
+			 * comparison after stripping the pkgrel from ptr1. */
+			*ptr1 = '\0';
+		} else if(*ptr2 == '-') {
+			/* ptr2 has hit the pkgrel and ptr1 has not. continue version
+			 * comparison after stripping the pkgrel from ptr2. */
+			*ptr2 = '\0';
+		}
+	}
+
+	/* this catches the case where all numeric and alpha segments have */
+	/* compared identically but the segment separating characters were */
+	/* different */
+	if ((!*one) && (!*two)) {
+		ret = 0;
+		goto cleanup;
+	}
+
+	/* the final showdown. we never want a remaining alpha string to
+	 * beat an empty string. the logic is a bit weird, but:
+	 * - if one is empty and two is not an alpha, two is newer.
+	 * - if one is an alpha, two is newer.
+	 * - otherwise one is newer.
+	 * */
+	if ( ( !*one && !isalpha((int)*two) )
+			|| isalpha((int)*one) ) {
+		ret = -1;
+	} else {
+		ret = 1;
+	}
+
+cleanup:
+	free(str1);
+	free(str2);
+	return(ret);
+}
+
+/* vim: set ts=2 sw=2 noet: */