Make MHK 2 packing and unpacking finally work

pkg/transformers/mhk_1.go

@@ -89,6 +89,6 @@ func transformMhk1(action string, dataFileLocation string, rootFolder string) er
 	case "unpack":
 		return unpackMhk1(dataFileLocation, rootFolder)
 	default:
-		return errors.New("Invalid action!")
+		return errors.New("invalid action")
 	}
 }

pkg/transformers/mhk_2.go

@@ -13,18 +13,17 @@ import (
 
 // Packs MHK2 data file from given `inputFolder` into `dataFileLocation`.
 func packMhk2(dataFileLocation string, inputPath string) error {
-	log.Printf("Creating `%s`...", dataFileLocation)
-	outFile, err := os.Create(dataFileLocation)
+	files, err := walkFiles(inputPath)
 	if err != nil {
 		return err
 	}
-	defer outFile.Close()
 
-	files, err := walkFiles(inputPath)
+	log.Printf("Packing %d files...", len(files))
+	outFile, err := os.Create(dataFileLocation)
 	if err != nil {
 		return err
 	}
-	log.Printf("Packing %d files...", len(files))
+	defer outFile.Close()
 
 	// header
 	log.Println("Generating header...")
@@ -35,12 +34,10 @@ func packMhk2(dataFileLocation string, inputPath string) error {
 
 	// save file entry data
 	log.Println("Saving file entries data...")
-	offset := int64(0x40) + int64(len(files)*0x80)
+	offset := int64(0x40 + len(files) * 0x80)
 	for _, file := range files {
 		fileEntry := make([]byte, 0x80)
-		relativePath, _ := filepath.Rel(inputPath, file.Filename)
-		pathWithPrefix := strings.ReplaceAll(relativePath, "/", "\\")
-		copy(fileEntry, pathWithPrefix)
+		copy(fileEntry, strings.ReplaceAll(file.Filename, "/", "\\"))
 
 		binary.LittleEndian.PutUint64(fileEntry[0x68:], uint64(offset))
 		binary.LittleEndian.PutUint64(fileEntry[0x6C:], uint64(file.Filesize))
@@ -65,18 +62,13 @@ func packMhk2(dataFileLocation string, inputPath string) error {
 		}
 
 		// write data
-		paddingLength := 0x100 - (len(fileData) % 0x100)
-		if paddingLength == 0x100 {
-			paddingLength = 0 // no padding needed if `fileData` is already aligned
-		}
-		padding := make([]byte, paddingLength)
-
 		log.Printf("Writing `%s`...", file.Filename)
+		padding := make([]byte, file.Filesize % 0x100)
 		if _, err := outFile.Write(append(fileData, padding...)); err != nil {
 			return err
 		}
 	}
-
+ 
 	return nil
 }
 
@@ -160,15 +152,15 @@ func unpackMhk2(dataFileLocation string, outputPath string) error {
 // Extracts the file position from a file entry block.
 func getPosition(fileEntry []byte) (uint32, error) {
 	if len(fileEntry) < 104 {
-		return 0, errors.New("Input data must have at least 104 bytes")
+		return 0, errors.New("input data must have at least 104 bytes")
 	}
 	return binary.LittleEndian.Uint32(fileEntry[0x68:0x6C]), nil
 }
 
 // Extracts the file length from a file entry block.
 func getFileLength(fileEntry []byte) (uint32, error) {
 	if len(fileEntry) < 108 {
-		return 0, errors.New("Input data must have at least 108 bytes")
+		return 0, errors.New("input data must have at least 108 bytes")
 	}
 	return binary.LittleEndian.Uint32(fileEntry[0x6C:0x70]), nil
 }
@@ -240,6 +232,6 @@ func transformMhk2(action string, dataFileLocation string, rootFolder string) er
 	case "unpack":
 		return unpackMhk2(dataFileLocation, rootFolder)
 	default:
-		return errors.New("Invalid action!")
+		return errors.New("invalid action")
 	}
 }

pkg/transformers/mhk_3.go

@@ -19,6 +19,6 @@ func transformMhk3(action string, dataFileLocation string, rootFolder string) er
 	case "unpack":
 		return unpackMhk3(dataFileLocation, rootFolder)
 	default:
-		return errors.New("Invalid action!")
+		return errors.New("invalid action")
 	}
 }

pkg/transformers/mhk_4.go

@@ -19,6 +19,6 @@ func transformMhk4(action string, dataFileLocation string, rootFolder string) er
 	case "unpack":
 		return unpackMhk4(dataFileLocation, rootFolder)
 	default:
-		return errors.New("Invalid action!")
+		return errors.New("invalid action")
 	}
 }

pkg/transformers/root.go

@@ -15,7 +15,7 @@ type FileEntry struct {
 	Filesize int64
 }
 
-// Walks through files in `rootFolder` and returns array of file entries.
+// Walks through files in `rootFolder` and returns array of relative file entries.
 func walkFiles(rootFolder string) ([]FileEntry, error) {
 	var files []FileEntry
 
@@ -40,7 +40,7 @@ func walkFiles(rootFolder string) ([]FileEntry, error) {
 		return nil
 	})
 	if err != nil {
-		return nil, errors.New(fmt.Sprintf("error walking through files: %s", err))
+		return nil, fmt.Errorf("error walking through files: %s", err)
 	}
 
 	return files, nil
@@ -52,7 +52,7 @@ func walkFiles(rootFolder string) ([]FileEntry, error) {
 func xorData(data []byte, key []byte) []byte {
 	keyLength := len(key)
 	for i := range data {
-		data[i] ^= key[i%keyLength]
+		data[i] ^= key[i % keyLength]
 	}
 	return data
 }
@@ -72,14 +72,13 @@ func Transform(action string, gameId string, dataFileLocation string, rootFolder
 	case "mhk_4", "mhk_thunder":
 		transformFunction = transformMhk4
 	default:
-		return errors.New("Invalid game ID! Please, use one of the following: `mhk_extra`, `mhk_1`, `mhk_2`, `schatzjaeger`, `mhk_3`, `mhk_4`, `mhk_thunder`.")
+		return errors.New("invalid game ID! Please, use one of the following: `mhk_extra`, `mhk_1`, `mhk_2`, `schatzjaeger`, `mhk_3`, `mhk_4`, `mhk_thunder`")
 	}
 
-	var err error
-	err = transformFunction(action, dataFileLocation, rootFolder)
+	err := transformFunction(action, dataFileLocation, rootFolder)
 
 	if err != nil {
-		return errors.New(fmt.Sprintf("Error transforming data: %s", err))
+		return fmt.Errorf("error transforming data: %s", err)
 	}
 
 	return nil

pkg/transformers/zip.go

@@ -2,7 +2,6 @@ package transformers
 
 import (
 	"archive/zip"
-	"errors"
 	"fmt"
 	"io"
 	"os"
@@ -12,13 +11,13 @@ import (
 // Unzip a file into a folder.
 func unzipFile(zipFile string, outputFolder string) error {
 	if err := os.MkdirAll(outputFolder, os.ModePerm); err != nil {
-		return errors.New(fmt.Sprintf("error creating output folder: %s", err))
+		return fmt.Errorf("error creating output folder: %s", err)
 	}
 
 	// unzip
 	zipReader, err := zip.OpenReader(zipFile)
 	if err != nil {
-		return errors.New(fmt.Sprintf("error opening ZIP file: %s", err))
+		return fmt.Errorf("error opening ZIP file: %s", err)
 	}
 	defer zipReader.Close()
 
@@ -28,23 +27,23 @@ func unzipFile(zipFile string, outputFolder string) error {
 		// read
 		fileReader, err := file.Open()
 		if err != nil {
-			return errors.New(fmt.Sprintf("error opening file: %s", err))
+			return fmt.Errorf("error opening file: %s", err)
 		}
 		defer fileReader.Close()
 
 		if err = os.MkdirAll(filepath.Dir(filePath), os.ModePerm); err != nil {
-			return errors.New(fmt.Sprintf("error creating directory: %s", err))
+			return fmt.Errorf("error creating directory: %s", err)
 		}
 
 		// write
 		outFile, err := os.Create(filePath)
 		if err != nil {
-			return errors.New(fmt.Sprintf("error creating file: %s", err))
+			return fmt.Errorf("error creating file: %s", err)
 		}
 		defer outFile.Close()
 
 		if _, err = io.Copy(outFile, fileReader); err != nil {
-			return errors.New(fmt.Sprintf("error copying file: %s", err))
+			return fmt.Errorf("error copying file: %s", err)
 		}
 	}
 
@@ -56,7 +55,7 @@ func zipFolder(folder string, zipFile string) error {
 	// open
 	outFile, err := os.Create(zipFile)
 	if err != nil {
-		return errors.New(fmt.Sprintf("error creating ZIP file: %s", err))
+		return fmt.Errorf("error creating ZIP file: %s", err)
 	}
 	defer outFile.Close()
 	zipWriter := zip.NewWriter(outFile)
@@ -100,7 +99,7 @@ func zipFolder(folder string, zipFile string) error {
 		return nil
 	})
 	if err != nil {
-		return errors.New(fmt.Sprintf("error while walking through files: %s", err))
+		return fmt.Errorf("error while walking through files: %s", err)
 	}
 
 	return nil