Initial DDC release

internal/extract/zip.go

@@ -0,0 +1,44 @@
+package extract
+
+import "archive/zip"
+
+func extractZip(archivePath string, writer *entryWriter) error {
+	reader, err := zip.OpenReader(archivePath)
+	if err != nil {
+		return err
+	}
+	defer reader.Close()
+
+	var declaredBytes uint64
+	for _, file := range reader.File {
+		declaredBytes += file.UncompressedSize64
+	}
+	if declaredBytes > uint64(writer.limits.MaxBytes) {
+		return ErrTooLarge
+	}
+	writer.progress.SetTotal(int64(declaredBytes))
+
+	for _, file := range reader.File {
+		if err := extractZipEntry(file, writer); err != nil {
+			return err
+		}
+	}
+	return nil
+}
+
+func extractZipEntry(file *zip.File, writer *entryWriter) error {
+	mode := file.Mode()
+	switch {
+	case mode.IsDir():
+		return writer.writeDirectory(file.Name)
+	case mode.IsRegular():
+		content, err := file.Open()
+		if err != nil {
+			return err
+		}
+		defer content.Close()
+		return writer.writeFile(file.Name, content)
+	default:
+		return nil
+	}
+}