Sync with rpm-4_0 branch.

CVS patchset: 4876
CVS date: 2001/06/17 22:18:03

1 files changed, 103 insertions, 0 deletions

diff --git a/lib/rpmvercmp.c b/lib/rpmvercmp.c
new file mode 100644
index 000000000..ec09447dd
--- /dev/null
+++ b/lib/rpmvercmp.c
@@ -0,0 +1,103 @@
+/** \ingroup rpmtrans
+ * \file lib/rpmvercmp.c
+ */
+
+#include "system.h"
+
+#include <rpmio.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++;
+
+	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 (xisdigit(*str1)) {
+	    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;
+	}
+
+	/* 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';
+
+	/* take care of the case where the two version segments are */
+	/* different types: one numeric, the other alpha (i.e. empty) */
+	if (one == str1) return -1;	/* arbitrary */
+	if (two == str2) return 1;
+
+	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;
+}