Added context to downloader and moved method from utils to downloader

utils.go

@@ -1,11 +1,7 @@
 package crunchyroll
 
 import (
-	"crypto/cipher"
 	"encoding/json"
-	"github.com/grafov/m3u8"
-	"io/ioutil"
-	"net/http"
 )
 
 func decodeMapToStruct(m interface{}, s interface{}) error {
@@ -16,34 +12,6 @@ func decodeMapToStruct(m interface{}, s interface{}) error {
 	return json.Unmarshal(jsonBody, s)
 }
 
-// https://github.com/oopsguy/m3u8/blob/4150e93ec8f4f8718875a02973f5d792648ecb97/tool/crypt.go#L25
-func decryptSegment(client *http.Client, segment *m3u8.MediaSegment, block cipher.Block, iv []byte) ([]byte, error) {
-	resp, err := client.Get(segment.URI)
-	if err != nil {
-		return nil, err
-	}
-	defer resp.Body.Close()
-
-	raw, err := ioutil.ReadAll(resp.Body)
-	if err != nil {
-		return nil, err
-	}
-
-	blockMode := cipher.NewCBCDecrypter(block, iv[:block.BlockSize()])
-	decrypted := make([]byte, len(raw))
-	blockMode.CryptBlocks(decrypted, raw)
-	raw = pkcs5UnPadding(decrypted)
-
-	return raw, nil
-}
-
-// https://github.com/oopsguy/m3u8/blob/4150e93ec8f4f8718875a02973f5d792648ecb97/tool/crypt.go#L47
-func pkcs5UnPadding(origData []byte) []byte {
-	length := len(origData)
-	unPadding := int(origData[length-1])
-	return origData[:(length - unPadding)]
-}
-
 func regexGroups(parsed [][]string, subexpNames ...string) map[string]string {
 	groups := map[string]string{}
 	for _, match := range parsed {