From a6f5f1b6b90008e73fa57882276bc643c039bb09 Mon Sep 17 00:00:00 2001
From: oetiker <oetiker@a5681a0c-68f1-0310-ab6d-d61299d08faa>
Date: Sun, 5 Jun 2005 22:23:32 +0000
Subject: [PATCH] New functions for CDEF ATAN2 RAD2DEG and DEG2RAD -- Simon
 Melhuish <simon mailing from melhuish.info>

git-svn-id: svn://svn.oetiker.ch/rrdtool/branches/1.2/program@610 a5681a0c-68f1-0310-ab6d-d61299d08faa
---
 doc/rrdgraph_rpn.pod | 15 ++++++++++++++-
 src/rrd_rpncalc.c    | 21 +++++++++++++++++++++
 src/rrd_rpncalc.h    |  3 ++-
 3 files changed, 37 insertions(+), 2 deletions(-)

diff --git a/doc/rrdgraph_rpn.pod b/doc/rrdgraph_rpn.pod
index 4585850..74ac4ad 100644
--- a/doc/rrdgraph_rpn.pod
+++ b/doc/rrdgraph_rpn.pod
@@ -107,11 +107,24 @@ B<ATAN>
 
 Arctangent (output in radians).
 
+B<ATAN2>
+
+Arctangent of y,x components (output in radians).
+This pops one element from the stack, the x (cosine) component, and then
+a second, which is the y (sine) component.
+It then pushes the arctangent of their ratio, resolving the ambiguity between
+quadrants.
+
+Example: C<CDEF:angle=Y,X,ATAN2,RAD2DEG> will convert C<X,Y>
+components into an angle in degrees.
+
 B<FLOOR, CEIL>
 
 Round down or up to the nearest integer.
 
-Z<>
+B<DEG2RAD, RAD2DEG>
+
+Convert angle in degrees to radians, or radians to degrees.
 
 =item Set Operations
 
diff --git a/src/rrd_rpncalc.c b/src/rrd_rpncalc.c
index 1fd30aa..688becc 100644
--- a/src/rrd_rpncalc.c
+++ b/src/rrd_rpncalc.c
@@ -153,11 +153,14 @@ void rpn_compact2str(rpn_cdefds_t *rpnc,ds_def_t *ds_def,char **str)
 	  add_op(OP_NOW,NOW)
 	  add_op(OP_LTIME,LTIME)
 	  add_op(OP_TIME,TIME)
+         add_op(OP_ATAN2,ATAN2)
 	  add_op(OP_ATAN,ATAN)
 	  add_op(OP_SQRT,SQRT)
 	  add_op(OP_SORT,SORT)
 	  add_op(OP_REV,REV)
 	  add_op(OP_TREND,TREND)
+         add_op(OP_RAD2DEG,RAD2DEG)
+         add_op(OP_DEG2RAD,DEG2RAD)
 #undef add_op
               }
     (*str)[offset] = '\0';
@@ -325,11 +328,14 @@ rpn_parse(void *key_hash,char *expr,long (*lookup)(void *,char*)){
 	match_op(OP_ISINF,ISINF)
 	match_op(OP_NOW,NOW)
 	match_op(OP_TIME,TIME)
+       match_op(OP_ATAN2,ATAN2)
 	match_op(OP_ATAN,ATAN)
 	match_op(OP_SQRT,SQRT)
 	match_op(OP_SORT,SORT)
 	match_op(OP_REV,REV)
 	match_op(OP_TREND,TREND)
+       match_op(OP_RAD2DEG,RAD2DEG)
+       match_op(OP_DEG2RAD,DEG2RAD)
 #undef match_op
 
 
@@ -524,6 +530,21 @@ rpn_calc(rpnp_t *rpnp, rpnstack_t *rpnstack, long data_idx,
 		stackunderflow(0);
 		rpnstack -> s[stptr] = atan(rpnstack -> s[stptr]);
 		break;
+           case OP_RAD2DEG:
+               stackunderflow(0);
+               rpnstack -> s[stptr] = 57.29577951 * rpnstack -> s[stptr];
+               break;
+           case OP_DEG2RAD:
+               stackunderflow(0);
+               rpnstack -> s[stptr] = 0.0174532952 * rpnstack -> s[stptr];
+               break;
+           case OP_ATAN2:
+               stackunderflow(1);
+               rpnstack -> s[stptr-1]= atan2(
+                               rpnstack -> s[stptr-1],
+                               rpnstack -> s[stptr]);
+               stptr--;
+               break;
 	    case OP_COS:
 		stackunderflow(0);
 		rpnstack -> s[stptr] = cos(rpnstack -> s[stptr]);
diff --git a/src/rrd_rpncalc.h b/src/rrd_rpncalc.h
index 56348db..146e2aa 100644
--- a/src/rrd_rpncalc.h
+++ b/src/rrd_rpncalc.h
@@ -16,7 +16,8 @@ enum op_en {OP_NUMBER=0,OP_VARIABLE,OP_INF,OP_PREV,OP_NEGINF,
 	    OP_COS,OP_LOG,OP_EXP,OP_LT,OP_LE,OP_GT,OP_GE,OP_EQ,OP_IF,
 	    OP_MIN,OP_MAX,OP_LIMIT, OP_FLOOR, OP_CEIL,
 	    OP_UN,OP_END,OP_LTIME,OP_NE,OP_ISINF,OP_PREV_OTHER,OP_COUNT,
-	    OP_ATAN,OP_SQRT,OP_SORT,OP_REV,OP_TREND};
+           OP_ATAN,OP_SQRT,OP_SORT,OP_REV,OP_TREND,
+           OP_ATAN2,OP_RAD2DEG,OP_DEG2RAD};
 
 typedef struct rpnp_t {
     enum op_en   op;
-- 
2.11.0