Utility data structures and functions.

utilities/utils.go

@@ -0,0 +1,54 @@
+package utilities
+
+import "errors"
+
+/*
+The Pair and PairList have been taken from google groups forum,
+https://groups.google.com/forum/#!topic/golang-nuts/FT7cjmcL7gw
+*/
+
+// Utility struct that helps in sorting the available power by value.
+type Pair struct {
+  Key string
+  Value float64
+}
+
+// A slice of pairs that implements the sort.Interface to sort by value.
+type PairList []Pair
+
+// Swap pairs in the PairList
+func (plist PairList) Swap(i, j int) {
+  plist[i], plist[j] = plist[j], plist[i]
+}
+
+// function to return the length of the pairlist.
+func (plist PairList) Len() int {
+  return len(plist)
+}
+
+// function to compare two elements in pairlist.
+func (plist PairList) Less(i, j int) bool {
+  return plist[i].Value < plist[j].Value
+}
+
+// convert a PairList to a map[string]float64
+func OrderedKeys(plist PairList) ([]string, error) {
+  // Validation
+  if plist == nil {
+    return nil, errors.New("Invalid argument: plist")
+  }
+  ordered_keys := make([]string, len(plist))
+  for _, pair := range plist {
+    ordered_keys = append(ordered_keys, pair.Key)
+  }
+  return ordered_keys, nil
+}
+
+// determine the max value
+func Max(a, b float64) float64 {
+  if a > b {
+    return a
+  } else {
+    return b
+  }
+}