fixed #4

embed compressed data into WAV files and improve data extraction handling

audio.go

@@ -1,23 +1,31 @@
 package stegano
 
 import (
+	"fmt"
+
 	u "github.com/scott-mescudi/stegano/pkg"
+	c "github.com/scott-mescudi/stegano/compression"
 )
 
 // EmbedDataIntoWAVWithDepth embeds compressed data into a WAV file with a specified bit depth.
 func (s *AudioEmbedHandler) EmbedDataIntoWAVWithDepth(audioFilename, outputFilename string, data []byte, bitDepth uint8) ( error) {
 	if bitDepth >= 8 {
 		return ErrDepthOutOfRange
 	}
+
+	nd, err := c.CompressZSTD(data)
+	if err != nil {
+		return err
+	}
+
 
 	decoder := GetAudioData(audioFilename)
 	buffer, err := decoder.FullPCMBuffer()
 	if err != nil {
 		return err
 	}
 
-
-	buffer = u.EmbedDataWithDepthAudio(buffer, data, bitDepth)
+	buffer = u.EmbedDataWithDepthAudio(buffer, nd, bitDepth)
 
 	err = WriteAudioFile(outputFilename, decoder, buffer)
 	if err != nil {
@@ -40,8 +48,35 @@ func (s *AudioExtractHandler) ExtractDataFromWAVWithDepth(audioFilename string,
 	}
 
 	data := u.ExtractDataWithDepthAudio(buffer, bitDepth)
+
 
-	return data, nil
+	lenData, err := u.GetlenOfData(data)
+	if err != nil {
+		return nil, err
+	}
+
+
+	var moddedData = make([]byte, 0, lenData)
+	defer func() {
+		if r := recover(); r != nil {
+			moddedData = nil
+			err = fmt.Errorf("fatal error: %v", r)
+		}
+	}()
+
+	for i := 4; i < lenData+4; i++ {
+		if i >= len(data) {
+			return nil, fmt.Errorf("index out of range while accessing data: %d", i)
+		}
+		moddedData = append(moddedData, data[i])
+	}
+
+	nd, err := c.DecompressZSTD(moddedData)
+	if err != nil {
+		return nil, err
+	}
+
+	return nd, nil
 }
 
 // EmbedDataIntoWAVAtDepth embeds compressed data into a WAV file at a specified bit depth.

pkg/audio.go

@@ -36,8 +36,7 @@ func ExtractDataAtDepthAudio(buffer *audio.IntBuffer, depth uint8) []byte {
 		}
 	}
 
-	leng, _ := GetlenOfData(data)
-	return data[4:(leng*2)+1]
+	return data
 }
 
 
@@ -90,7 +89,6 @@ func ExtractDataWithDepthAudio(buffer *audio.IntBuffer, depth uint8) []byte {
 	}
 
 
-	leng, _ := GetlenOfData(byteSlice)
-	return byteSlice[4:(leng*2)+1]
+	return byteSlice
 }