X-Git-Url: https://git.octo.it/?a=blobdiff_plain;f=src%2Frrd_diff.c;h=07f8fb3b154e87551f157a2673b66e1cc653a18a;hb=3e4e57c524ed5bbded8aa2a96cd99c5c26c980cf;hp=1d0d1f54f2ff9f0619ee22e3343a8ed3f1b14075;hpb=5837606887a6d81e8b1f7588525cb1c8783fb62b;p=rrdtool.git

diff --git a/src/rrd_diff.c b/src/rrd_diff.c
index 1d0d1f5..07f8fb3 100644
--- a/src/rrd_diff.c
+++ b/src/rrd_diff.c
@@ -1,5 +1,5 @@
 /*****************************************************************************
- * RRDtool 1.0.33  Copyright Tobias Oetiker, 1999
+ * RRDtool 1.4.3  Copyright by Tobi Oetiker, 1997-2010
  * This code is stolen from rateup (mrtg-2.x) by Dave Rand
  *****************************************************************************
  * diff calculate the difference between two very long integers available as
@@ -7,8 +7,19 @@
  *****************************************************************************
  * $Id$
  * $Log$
- * Revision 1.1  2001/02/25 22:25:05  oetiker
- * Initial revision
+ * Revision 1.4  2003/03/10 00:30:34  oetiker
+ * handle cases with two negative numbers
+ * --  Sasha Mikheev <sasha@avalon-net.co.il>
+ *
+ * Revision 1.3  2002/04/01 18:31:22  oetiker
+ * "!" takes a higher preference than "||" this means rrd_update N:: would
+ * segfault -- Oliver Cook <ollie@uk.clara.net>
+ *
+ * Revision 1.2  2002/02/01 20:34:49  oetiker
+ * fixed version number and date/time
+ *
+ * Revision 1.1.1.1  2001/02/25 22:25:05  oetiker
+ * checkin
  *
  * Revision 1.1  1998/10/08 18:21:45  oetiker
  * Initial revision
@@ -24,38 +35,52 @@
  *
  *****************************************************************************/
 
+#include <ctype.h>
 #include "rrd_tool.h"
 
-double
-rrd_diff(char *a, char *b)
+double rrd_diff(
+    char *a,
+    char *b)
 {
-    char res[LAST_DS_LEN+1], *a1, *b1, *r1, *fix;
-    int c,x,m;
-    
-    while (!isdigit((int)*a) || *a==0)
+    char      res[LAST_DS_LEN + 1], *a1, *b1, *r1, *fix;
+    int       c, x, m;
+    char      a_neg = 0, b_neg = 0;
+    double    result;
+
+    while (!(isdigit((int) *a) || *a == 0)) {
+        if (*a == '-')
+            a_neg = 1;
         a++;
-    fix=a;
-    while (isdigit((int)*fix)) 
-	fix++;
-    *fix = 0; /* maybe there is some non digit data in the string */ 
-    while (!isdigit((int)*b) || *b==0)
+    }
+    fix = a;
+    while (isdigit((int) *fix))
+        fix++;
+    *fix = 0;           /* maybe there is some non digit data in the string */
+    while (!(isdigit((int) *b) || *b == 0)) {
+        if (*b == '-')
+            b_neg = 1;
         b++;
-    fix=b;
-    while (isdigit((int)*fix)) 
-	fix++;
-    *fix = 0; /* maybe there is some non digit data in the string */ 
-    if(!isdigit((int)*a) || !isdigit((int)*b))
-	return DNAN;
-    a1 = &a[strlen(a)-1];
-    m = max(strlen(a),strlen(b));
-    if (m > LAST_DS_LEN) return DNAN; /* result string too short */
+    }
+    fix = b;
+    while (isdigit((int) *fix))
+        fix++;
+    *fix = 0;           /* maybe there is some non digit data in the string */
+    if (!isdigit((int) *a) || !isdigit((int) *b))
+        return DNAN;
+    if (a_neg + b_neg == 1) /* can not handle numbers with different signs yet */
+        return DNAN;
+    a1 = &a[strlen(a) - 1];
+    m = max(strlen(a), strlen(b));
+    if (m > LAST_DS_LEN)
+        return DNAN;    /* result string too short */
 
-    r1 = &res[m+1];
-    for (b1 = res;b1 <= r1; b1++) *b1 = ' ';
-    b1 = &b[strlen(b)-1];
-    r1[1] = 0;  /* Null terminate result */
+    r1 = &res[m + 1];
+    for (b1 = res; b1 <= r1; b1++)
+        *b1 = ' ';
+    b1 = &b[strlen(b) - 1];
+    r1[1] = 0;          /* Null terminate result */
     c = 0;
-    for (x=0; x<m; x++) {
+    for (x = 0; x < m; x++) {
         if (a1 >= a && b1 >= b) {
             *r1 = ((*a1 - c) - *b1) + '0';
         } else if (a1 >= a) {
@@ -65,28 +90,34 @@ rrd_diff(char *a, char *b)
         }
         if (*r1 < '0') {
             *r1 += 10;
-            c=1;
-        } else
-	  if (*r1 > '9') { /* 0 - 10 */
-	    *r1 -= 10;
-	    c=1;	    
-	  } else {
-            c=0;
+            c = 1;
+        } else if (*r1 > '9') { /* 0 - 10 */
+            *r1 -= 10;
+            c = 1;
+        } else {
+            c = 0;
         }
-        a1--;b1--;r1--;
+        a1--;
+        b1--;
+        r1--;
     }
     if (c) {
-        r1 = &res[m+1];
-        for (x=0; isdigit((int)*r1) && x<m; x++,r1--)  {
+        r1 = &res[m + 1];
+        for (x = 0; isdigit((int) *r1) && x < m; x++, r1--) {
             *r1 = ('9' - *r1 + c) + '0';
             if (*r1 > '9') {
                 *r1 -= 10;
-                c=1;
+                c = 1;
             } else {
-                c=0;
+                c = 0;
             }
         }
-        return(-atof(res));
+        result = -atof(res);
     } else
-        return(atof(res));
-}                                                       
+        result = atof(res);
+
+    if (a_neg + b_neg == 2) /* both are negatives, reverse sign */
+        result = -result;
+
+    return result;
+}