Minor improvements

README.md

@@ -24,7 +24,7 @@ If multiple `Carrier` files are provided, the `Data` file will be split in piece
 | ---------------------------------------------|--------------------------------------------|--------------------------------------------|------------------------------------------------------------------|------------------------------------------------------------------|
 | <img src="examples/street.jpeg" width="500"> | <img src="examples/lake.jpeg" width="500"> | <img src="examples/video.gif" width="500"> | <img src="examples/test_multi_carrier_decode1.jpeg" width="500"> | <img src="examples/test_multi_carrier_decode2.jpeg" width="500"> |
 
-The `Result1` file contains a portion of the `Data` file hidden in it as well as `Result2` contains the rest. As always fully transparent.
+The `Result1` file contains one half of the `Data` file hidden in it and `Result2` the other. As always fully transparent.
 
 ## Install
 ```

steg/steg_decode.go

@@ -1,13 +1,11 @@
 package steg
 
 import (
-	"bytes"
 	"encoding/binary"
 	"fmt"
 	"github.com/DimitarPetrov/stegify/bits"
 	"image"
 	"io"
-	"io/ioutil"
 	"os"
 )
 
@@ -61,17 +59,9 @@ func Decode(carrier io.Reader, result io.Writer) error {
 //NOTE: The order of the carriers MUST be the same as the one when encoding.
 func MultiCarrierDecode(carriers []io.Reader, result io.Writer) error {
 	for i := 0; i < len(carriers); i++ {
-		var chunkResult bytes.Buffer
-		if err := Decode(carriers[i], &chunkResult); err != nil {
+		if err := Decode(carriers[i], result); err != nil {
 			return fmt.Errorf("error decoding chunk with index %d: %v", i, err)
 		}
-		chunkBytes, err := ioutil.ReadAll(&chunkResult)
-		if err != nil {
-			return err
-		}
-		if _, err := result.Write(chunkBytes); err != nil {
-			return err
-		}
 	}
 	return nil
 }

steg/steg_encode.go

@@ -104,7 +104,7 @@ func MultiCarrierEncode(carriers []io.Reader, data io.Reader, results []io.Write
 	chunksCount := 0
 	for i := 0; i < len(dataBytes) && chunksCount < len(carriers); i += chunkSize {
 		chunksCount++
-		if i+chunkSize >= len(dataBytes) || chunksCount == len(carriers){ // last iteration
+		if i+chunkSize >= len(dataBytes) || chunksCount == len(carriers) { // last iteration
 			dataChunks = append(dataChunks, bytes.NewReader(dataBytes[i:]))
 		}
 		dataChunks = append(dataChunks, bytes.NewReader(dataBytes[i:i+chunkSize]))

steg/steg_encode_test.go

@@ -232,15 +232,15 @@ func TestMultiCarrierEncodeShouldReturnErrorWhenDataFileTooLarge(t *testing.T) {
 
 	var result1 bytes.Buffer
 	var result2 bytes.Buffer
-	err = steg.MultiCarrierEncode([]io.Reader{carrier1,carrier2}, data, []io.Writer{&result1, &result2})
+	err = steg.MultiCarrierEncode([]io.Reader{carrier1, carrier2}, data, []io.Writer{&result1, &result2})
 	if err == nil {
 		t.FailNow()
 	}
 	t.Log(err)
 }
 
 func TestMultiCarrierEncodeByFileNamesShouldReturnErrorWhenDataFileTooLarge(t *testing.T) {
-	err := steg.MultiCarrierEncodeByFileNames([]string{"../examples/lake.jpeg","../examples/street.jpeg"}, "../examples/test_decode.jpeg", []string{"result1", "result2"})
+	err := steg.MultiCarrierEncodeByFileNames([]string{"../examples/lake.jpeg", "../examples/street.jpeg"}, "../examples/test_decode.jpeg", []string{"result1", "result2"})
 	if err == nil {
 		os.Remove("result1")
 		os.Remove("result2")

stegify.go

@@ -24,22 +24,22 @@ func (sf *sliceFlag) Set(value string) error {
 }
 
 var carrierFilesSlice sliceFlag
-var carrierFiles = flag.String("carriers", "", "carrier files in which the data is encoded (separated by space and surrounded by quotes)")
-var dataFile = flag.String("data", "", "data file which is being encoded in carrier")
+var carrierFiles = flag.String("carriers", "", "carrier files in which the data is encoded (separated by space)")
+var dataFile = flag.String("data", "", "data file which is being encoded in the carrier")
 var resultFilesSlice sliceFlag
-var resultFiles = flag.String("results", "", "names of the result files (separated by space and surrounded by quotes)")
+var resultFiles = flag.String("results", "", "names of the result files (separated by space)")
 
 func init() {
-	flag.StringVar(carrierFiles, "c", "", "carrier files in which the data is encoded (separated by space surrounded by quotes, shorthand for --carriers)")
+	flag.StringVar(carrierFiles, "c", "", "carrier files in which the data is encoded (separated by space, shorthand for --carriers)")
 	flag.Var(&carrierFilesSlice, "carrier", "carrier file in which the data is encoded (could be used multiple times for multiple carriers)")
-	flag.StringVar(dataFile, "d", "", "data file which is being encoded in carrier (shorthand for --data)")
+	flag.StringVar(dataFile, "d", "", "data file which is being encoded in the carrier (shorthand for --data)")
 	flag.Var(&resultFilesSlice, "result", "name of the result file (could be used multiple times for multiple result file names)")
-	flag.StringVar(resultFiles, "r", "", "names of the result files (separated by space and surrounded by quotes, shorthand for --results)")
+	flag.StringVar(resultFiles, "r", "", "names of the result files (separated by space, shorthand for --results)")
 
 	flag.Usage = func() {
 		fmt.Fprintln(os.Stdout, "Usage: stegify [encode/decode] [flags...]")
 		flag.PrintDefaults()
-		fmt.Fprintln(os.Stdout, `NOTE: When multiple carriers are provided with different kinds of flags, the names provided through "carrier" flag are taken first and with "carriers"/"c" flags second. Same goes for the result/results flag.`)
+		fmt.Fprintln(os.Stdout, `NOTE: When multiple carriers are provided with different kinds of flags, the names provided through "carrier" flag are taken first and with "carriers"/"c" flags second. Same goes for the "result"/"results" flags.`)
 		fmt.Fprintln(os.Stdout, `NOTE: When no results are provided a default values will be used for the names of the results.`)
 	}
 }
@@ -50,34 +50,31 @@ func main() {
 	carriers := parseCarriers()
 	results := parseResults()
 
-	if len(results) == 0 {
-		if operation == encode {
+	switch operation {
+	case encode:
+		if len(results) == 0 { // if no results provided use defaults
 			for i := range carriers {
 				results = append(results, fmt.Sprintf("result%d", i))
 			}
-		} else {
-			results = append(results, "result")
 		}
-	}
-
-	if len(results) != len(carriers) && operation == encode {
-		fmt.Fprintln(os.Stderr, "Carrier and result files count must be equal when encoding.")
-		os.Exit(1)
-	}
-
-	if (dataFile == nil || *dataFile == "") && operation == encode {
-		fmt.Fprintln(os.Stderr, "Data file must be specified. Use stegify --help for more information.")
-		os.Exit(1)
-	}
+		if len(results) != len(carriers) {
+			fmt.Fprintln(os.Stderr, "Carrier and result files count must be equal when encoding.")
+			os.Exit(1)
+		}
+		if dataFile == nil || *dataFile == "" {
+			fmt.Fprintln(os.Stderr, "Data file must be specified. Use stegify --help for more information.")
+			os.Exit(1)
+		}
 
-	switch operation {
-	case encode:
 		err := steg.MultiCarrierEncodeByFileNames(carriers, *dataFile, results)
 		if err != nil {
 			fmt.Fprintln(os.Stderr, err)
 			os.Exit(1)
 		}
 	case decode:
+		if len(results) == 0 { // if no result provided use default
+			results = append(results, "result")
+		}
 		if len(results) != 1 {
 			fmt.Fprintln(os.Stderr, "Only one result file expected.")
 			os.Exit(1)

stegify_test.go

@@ -154,9 +154,9 @@ func TestDecode(t *testing.T) {
 		},
 		{
 			name:     "Decode from multiple carriers using --cariers flag",
-			args:     []string{"decode", "--carriers", "examples/test_multi_carrier_decode1.jpeg examples/test_multi_carrier_decode2.jpeg", "--result", "result1.mp4"},
+			args:     []string{"decode", "--carriers", "examples/test_multi_carrier_decode1.jpeg examples/test_multi_carrier_decode2.jpeg", "--result", "result2.mp4"},
 			expected: "examples/video.mp4",
-			result:   "result1.mp4",
+			result:   "result2.mp4",
 		},
 		{
 			name:     "Decode without result flag should add default",