From 79c122ebaaada74a9fd86442ff53d2a37bfe9b7e Mon Sep 17 00:00:00 2001
From: Florian Forster <ff@octo.it>
Date: Thu, 2 Jun 2011 09:52:32 +0200
Subject: [PATCH] Initial commit.

---
 compact.go | 161 +++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 161 insertions(+)
 create mode 100644 compact.go

diff --git a/compact.go b/compact.go
new file mode 100644
index 0000000..0698f68
--- /dev/null
+++ b/compact.go
@@ -0,0 +1,161 @@
+package main
+
+import (
+  "fmt"
+  "os"
+)
+
+type OTS_DataPoint struct {
+  TimeStamp float64
+  Rate      float64
+}
+
+type OTS_Data struct {
+  TSData []OTS_DataPoint
+}
+
+/* Functions for the sort interface. */
+func (obj *OTS_Data) Len () int {
+  return (len (obj.TSData))
+}
+
+func (obj *OTS_Data) Less (i, j int) bool {
+  if obj.TSData[i].TimeStamp < obj.TSData[j].TimeStamp {
+    return true
+  }
+  return false
+}
+
+func (obj *OTS_Data) Swap (i, j int) {
+  tmp := obj.TSData[i]
+  obj.TSData[i] = obj.TSData[j]
+  obj.TSData[j] = tmp
+}
+
+func Fmod64 (a float64, b float64) float64 {
+  tmp := int (a / b)
+  return b * float64 (tmp)
+}
+
+func (obj *OTS_Data) Write (name string) os.Error {
+  fd, err := os.OpenFile(name, os.O_WRONLY, 0666)
+  if err != nil {
+    return err
+  }
+
+  for i := 0; i < len (obj.TSData); i++ {
+    data_point := obj.TSData[i]
+    str := fmt.Sprintf ("%.3f,%g\n", data_point.TimeStamp, data_point.Rate)
+
+    fd.WriteString (str)
+  }
+
+  fd.Close ()
+  return nil
+}
+
+func ReadFile (name string) (obj *OTS_Data, err os.Error) {
+}
+
+func (raw_data *OTS_Data) Consolidate (interval float64) *OTS_Data {
+  if interval <= 0.0 {
+    return nil
+  }
+
+  ts_raw_first := raw_data.TSData[0].TimeStamp
+  ts_raw_last  := ts_raw_first
+
+  /* Determine the first and last data point.
+   * XXX: In the future, this should be a sorted list! */
+  for i := 1; i < len (raw_data.TSData); i++ {
+    data_point := raw_data.TSData[i]
+
+    if ts_raw_first > data_point.TimeStamp {
+      ts_raw_first = data_point.TimeStamp
+    }
+
+    if ts_raw_last < data_point.TimeStamp {
+      ts_raw_last = data_point.TimeStamp
+    }
+  }
+
+  fmt.Printf ("ts_raw_first = %g; ts_raw_last = %g;\n",
+      ts_raw_first, ts_raw_last)
+
+  /* Determine the timespan the consolidated data will span. */
+  ts_csl_first := Fmod64 (ts_raw_first, interval)
+  ts_csl_last  := Fmod64 (ts_raw_last,  interval)
+  if ts_csl_last < ts_raw_last {
+    ts_csl_last += interval
+  }
+
+  fmt.Printf ("ts_csl_first = %g; ts_csl_last = %g;\n",
+      ts_csl_first, ts_csl_last)
+
+  intervals_num := int ((ts_csl_last - ts_csl_first) / interval)
+  fmt.Printf ("Got a %gs timespan (%d intervals).\n",
+      ts_csl_last - ts_csl_first, intervals_num)
+
+  /* Allocate return structure */
+  ret_data := new (OTS_Data)
+  ret_data.TSData = make ([]OTS_DataPoint, intervals_num)
+
+  /* FIXME: This is currently a O(n^2) algorithm. It should instead be a O(n)
+   * algorithm. This is possible if raw_data is sorted (which, obviously, is a
+   * O(n log(n)) task). */
+  for i := 0; i < intervals_num; i++ {
+      ts := ts_csl_first + (float64 (i) * interval)
+      sum := 0.0
+      num := 0.0
+
+      fmt.Printf ("Building data for interval %g.\n", ts)
+
+      ret_data.TSData[i].TimeStamp = ts
+
+      for j := 0; j < len (raw_data.TSData); j++ {
+        data_point := raw_data.TSData[j]
+
+        if ((data_point.TimeStamp < ts) || (data_point.TimeStamp >= (ts + interval))) {
+          continue
+        }
+
+        sum += data_point.Rate
+        num += 1.0
+      }
+
+      /* TODO: Be more clever about how this consolidated rate is computed. */
+      if num > 0.0 {
+        ret_data.TSData[i].Rate = sum / num
+      }
+  }
+
+  return ret_data
+}
+
+func (obj *OTS_Data) Print () {
+  for i := 0; i < len (obj.TSData); i++ {
+    data_point := obj.TSData[i]
+    fmt.Printf ("[%g] %g\n", data_point.TimeStamp, data_point.Rate)
+  }
+} /* Print () */
+
+func main () {
+  var data_points []OTS_DataPoint
+  var raw_data     *OTS_Data
+  var new_data     *OTS_Data
+
+  data_points = []OTS_DataPoint {
+    {0.0,  1.0},
+    {1.0,  2.0},
+    {2.0,  5.0},
+    {3.0,  8.0},
+    {4.0,  0.0},
+    {5.0,  3.0}}
+
+  raw_data = new (OTS_Data)
+  raw_data.TSData = data_points
+
+  new_data = raw_data.Consolidate (2.0)
+
+  new_data.Print()
+}
-- 
2.11.0