Initial version

README.md

@@ -1,2 +1,3 @@
 # gravizool
-Gravizo tool
+
+Small [gravizo.com](http://gravizo.com) tool for encoding and decoding GitHub Markdown files based on the new [GitHub Flavored Markdown Spec](https://github.github.com/gfm/#link-destination).

gravizool.go

@@ -0,0 +1,64 @@
+package main
+
+import (
+    "os"
+    "fmt"
+    "flag"
+    "io/ioutil"
+    "strings"
+)
+
+const gravizoBegin string = "(http://g.gravizo.com/svg?"
+const gravizoEnd string = "enduml)"
+
+var encoder = strings.NewReplacer(";", "%3B", " ", "%20", "\n", "%0A", "@", "%40",
+    "(", "%28", ")", "%29", "*", "%2A", "\\", "%5C")
+var decoder = strings.NewReplacer("%3B", ";", "%20", " ", "%0A", "\n", "%40", "@",
+    "%2A", "*", "%5C", "\\")
+
+func check(err error) {
+    if err != nil {
+        fmt.Println(err)
+        os.Exit(1)
+    }
+}
+
+func convert(filename string, replacer *strings.Replacer, backup bool) {
+    buffer, err := ioutil.ReadFile(filename)
+    check(err)
+
+    if backup {
+        err = ioutil.WriteFile(fmt.Sprint(filename +  ".bak"), buffer, 0644)
+        check(err)
+    }
+
+    text := string(buffer)
+
+    for _, slice := range strings.Split(text, gravizoBegin) {
+        if strings.Contains(slice, gravizoEnd) {
+            subSlice := strings.Split(slice, gravizoEnd)
+            if len(subSlice) > 0 {
+                gravizoText := subSlice[0]
+                convertedText := replacer.Replace(gravizoText)
+                text = strings.Replace(text, gravizoText, convertedText, -1)
+            }
+        }
+    }
+
+    err = ioutil.WriteFile(filename, []byte(text), 0644)
+    check(err)
+}
+
+func main() {
+    encode := flag.String("e", "", "Encode the given GitHub Markdown file")
+    decode := flag.String("d", "", "Decode the given GitHub Markdown file")
+    backup := flag.Bool("b", true, "Backup GitHub Markdown file before encode/decode")
+
+    flag.Parse()
+
+    if len(*encode) > 0 {
+        convert(*encode, encoder, *backup)
+    } else if len(*decode) > 0 {
+        convert(*decode, decoder, *backup)
+    }
+}