Handle reading data from external CSV files

2 files changed, 71 insertions, 0 deletions

diff --git a/csv/csv.go b/csv/csv.go
new file mode 100644
index 0000000..63783ed
--- /dev/null
+++ b/csv/csv.go
@@ -0,0 +1,68 @@
+package csv
+
+import (
+	"../structs"
+	"encoding/csv"
+	"log"
+	"os"
+	"strconv"
+)
+
+// openStarCSV opens the file at the given path and reads its content. It then returns the content inform of a slice
+// of slices
+func openStarCSV(path string) [][]string {
+
+	// Open the file located at the given path
+	b, err := os.Open(path)
+
+	// Handle errors
+	if err != nil {
+		log.Printf("openStarsCSV Panic! (cannot read file from %s)", path)
+	}
+
+	// Close the file afre reading it's content
+	defer b.Close()
+
+	// Parse the files conten usin a csv-reader
+	lines, err := csv.NewReader(b).ReadAll()
+
+	// Handle errors
+	if err != nil {
+		log.Println("openStarsCSV Panic! (cannot read the files content)")
+	}
+
+	return lines
+}
+
+// Import gets a file, a starting line, an ending line and  a struct. It then adds the content of the file to the struct
+// For finding the length of the .csv, you can use the following command in linux:
+// $ cat <csv> | wc -l
+func Import(path string, start int, end int, slice []structs.Star) []structs.Star {
+	lines := openStarCSV(path)
+
+	for linenr, line := range lines[start:end] {
+		x, errx := strconv.ParseFloat(line[0], 64)
+		y, erry := strconv.ParseFloat(line[1], 64)
+
+		// Handle errors
+		if errx != nil {
+			log.Printf("error reading value from csv in line nr. %d (%s)", linenr, errx)
+		}
+		if errx != nil {
+			log.Printf("error reading value from csv in line nr. %d (%s)", linenr, erry)
+		}
+
+		// Create a temporary star for assembling the star
+		tempStar := structs.Star{
+			structs.Coord{x, y},
+			structs.Force{0, 0},
+			1000000,
+		}
+
+		// Add the Temporary star to the slice
+		slice = append(slice, tempStar)
+
+	}
+
+	return slice
+}
diff --git a/main.go b/main.go
index 454abe5..0cdd637 100644
--- a/main.go
+++ b/main.go
@@ -1,6 +1,7 @@
 package main
 
 import (
+	"./csv"
 	"./draw"
 	"./forces"
 	"./structs"
@@ -14,6 +15,8 @@ func main() {
 		{structs.Coord{X: 100, Y: 500}, structs.Force{0, 0}, 1000},
 	}
 
+	csv.Import("data/structure03.ita.uni-heidelberg.de_26635.csv", 0, 4000, starsSlice)
+
 	forces.CalcAllForces(starsSlice)
 	draw.Slice(starsSlice, "out.png")
 }