fix handling of PREV(x) command

[rrdtool.git] / src / rrd_graph.c

diff --git a/src/rrd_graph.c b/src/rrd_graph.c
index cbf947dc1ac631182171adeebb09d37d5538e763..b01bd3a365c2d35547cd0fb731fa174371696634 100644 (file)
--- a/src/rrd_graph.c
+++ b/src/rrd_graph.c
@@ -886,26 +886,29 @@ data_calc( image_desc_t *im){
                 *   and the resulting number is the step size for the
                 *   resulting data source.
                 */
-               for(rpi=0;im->gdes[gdi].rpnp[rpi].op != OP_END;rpi++){
-               if(im->gdes[gdi].rpnp[rpi].op == OP_VARIABLE ||
-                  im->gdes[gdi].rpnp[rpi].op == OP_PREV_OTHER){
-                       long ptr = im->gdes[gdi].rpnp[rpi].ptr;
-                       if (im->gdes[ptr].ds_cnt == 0) {
+               for(rpi=0;im->gdes[gdi].rpnp[rpi].op != OP_END;rpi++){
+                   if(im->gdes[gdi].rpnp[rpi].op == OP_VARIABLE  ||
+                       im->gdes[gdi].rpnp[rpi].op == OP_PREV_OTHER){
+                       long ptr = im->gdes[gdi].rpnp[rpi].ptr;
+                       if (im->gdes[ptr].ds_cnt == 0) { /* this is a VDEF data source */
 #if 0
-                       printf("DEBUG: inside CDEF '%s' processing VDEF '%s'\n",
-       im->gdes[gdi].vname,
-       im->gdes[ptr].vname);
-                       printf("DEBUG: value from vdef is %f\n",im->gdes[ptr].vf.val);
+                           printf("DEBUG: inside CDEF '%s' processing VDEF '%s'\n",
+                              im->gdes[gdi].vname,
+                              im->gdes[ptr].vname);
+                           printf("DEBUG: value from vdef is %f\n",im->gdes[ptr].vf.val);
 #endif
                            im->gdes[gdi].rpnp[rpi].val = im->gdes[ptr].vf.val;
                            im->gdes[gdi].rpnp[rpi].op  = OP_NUMBER;
-                       } else {
-                       if ((steparray =
+                       } else { /* normal variables and PREF(variables) */
+
+                           /* add one entry to the array that keeps track of the step sizes of the
+                            * data sources going into the CDEF. */
+                           if ((steparray =
                                 rrd_realloc(steparray,
                                                         (++stepcnt+1)*sizeof(*steparray)))==NULL){
-                               rrd_set_error("realloc steparray");
-                               rpnstack_free(&rpnstack);
-                               return -1;
+                                rrd_set_error("realloc steparray");
+                                rpnstack_free(&rpnstack);
+                                return -1;
                            };
 
                            steparray[stepcnt-1] = im->gdes[ptr].step;
@@ -915,6 +918,7 @@ data_calc( image_desc_t *im){
                             * to the earliest endpoint of any of the
                             * rras involved (ptr)
                             */
+
                            if(im->gdes[gdi].start < im->gdes[ptr].start)
                                im->gdes[gdi].start = im->gdes[ptr].start;
 
@@ -927,8 +931,8 @@ data_calc( image_desc_t *im){
                             * further save step size and data source
                             * count of this rra
                             */ 
-                            im->gdes[gdi].rpnp[rpi].data =  im->gdes[ptr].data + im->gdes[ptr].ds;
-                           im->gdes[gdi].rpnp[rpi].step = im->gdes[ptr].step;
+                            im->gdes[gdi].rpnp[rpi].data   = im->gdes[ptr].data + im->gdes[ptr].ds;
+                           im->gdes[gdi].rpnp[rpi].step   = im->gdes[ptr].step;
                            im->gdes[gdi].rpnp[rpi].ds_cnt = im->gdes[ptr].ds_cnt;
 
                            /* backoff the *.data ptr; this is done so
@@ -941,9 +945,9 @@ data_calc( image_desc_t *im){
 
                 /* move the data pointers to the correct period */
                 for(rpi=0;im->gdes[gdi].rpnp[rpi].op != OP_END;rpi++){
-               if(im->gdes[gdi].rpnp[rpi].op == OP_VARIABLE ||
-                  im->gdes[gdi].rpnp[rpi].op == OP_PREV_OTHER){
-                        long ptr = im->gdes[gdi].rpnp[rpi].ptr;
+                   if(im->gdes[gdi].rpnp[rpi].op == OP_VARIABLE ||
+                       im->gdes[gdi].rpnp[rpi].op == OP_PREV_OTHER){
+                       long ptr  = im->gdes[gdi].rpnp[rpi].ptr;
                        long diff = im->gdes[gdi].start - im->gdes[ptr].start;
 
                         if(diff > 0)