CGE: Add EncryptedStream class, remove seed parameter from XCrypt()

4 files changed, 37 insertions, 6 deletions

diff --git a/engines/cge/fileio.cpp b/engines/cge/fileio.cpp
index 7624eac936..87a1ffebac 100644
--- a/engines/cge/fileio.cpp
+++ b/engines/cge/fileio.cpp
@@ -61,7 +61,7 @@ uint16 IoHand::read(void *buf, uint16 len) {
 	if (!bytesRead)
 		error("Read %s - %d bytes", _file->getName(), len);
 	if (_crypt)
-		_seed = _crypt(buf, len, kCryptSeed);
+		_seed = _crypt(buf, len);
 	return bytesRead;
 }
 
@@ -378,4 +378,27 @@ long VFile::seek(long pos) {
 	return (_bufMark = _begMark + pos);
 }
 
+/*-----------------------------------------------------------------------
+ * EncryptedStream
+ *-----------------------------------------------------------------------*/
+EncryptedStream::EncryptedStream(const char *name) {
+	debugC(3, kCGEDebugFile, "EncryptedStream::EncryptedStream(%s)", name);
+
+	_error = false;
+	if (_dat->_error || _cat->_error)
+		error("Bad volume data");
+	BtKeypack *kp = _cat->find(name);
+	if (scumm_stricmp(kp->_key, name) != 0)
+		_error = true;
+
+	_dat->_file->seek(kp->_mark);
+	byte *dataBuffer = (byte *)malloc(kp->_size);
+	_dat->_file->read(dataBuffer, kp->_size);
+	XCrypt(dataBuffer, kp->_size);
+	_readStream = new Common::MemoryReadStream(dataBuffer, kp->_size, DisposeAfterUse::YES);
+}
+
+EncryptedStream::~EncryptedStream() {
+}
+
 } // End of namespace CGE
diff --git a/engines/cge/fileio.h b/engines/cge/fileio.h
index 65f0b953e7..68b9a26d76 100644
--- a/engines/cge/fileio.h
+++ b/engines/cge/fileio.h
@@ -147,6 +147,14 @@ public:
 	long seek(long pos);
 };
 
+class EncryptedStream {
+public:
+	bool _error;
+	EncryptedStream(const char *name);
+	~EncryptedStream();
+	Common::SeekableReadStream *_readStream;
+};
+
 extern CFile *_dat;
 extern BtFile *_cat;
 
diff --git a/engines/cge/general.cpp b/engines/cge/general.cpp
index c93cc1292b..7db61818ab 100644
--- a/engines/cge/general.cpp
+++ b/engines/cge/general.cpp
@@ -31,13 +31,13 @@
 
 namespace CGE {
 
-uint16 XCrypt(void *buf, uint16 siz, uint16 seed) {
+uint16 XCrypt(void *buf, uint16 siz) {
 	byte *b = static_cast<byte *>(buf);
 
 	for (uint16 i = 0; i < siz; i++)
-		*b++ ^= seed;
+		*b++ ^= kCryptSeed;
 	
-	return seed;
+	return kCryptSeed;
 }
 
 char *mergeExt(char *buf, const char *name, const char *ext) {
diff --git a/engines/cge/general.h b/engines/cge/general.h
index 8f997c9ae2..1793594d07 100644
--- a/engines/cge/general.h
+++ b/engines/cge/general.h
@@ -45,9 +45,9 @@ struct Dac {
 	uint8 _b;
 };
 
-typedef uint16 Crypt(void *buf, uint16 siz, uint16 seed);
+typedef uint16 Crypt(void *buf, uint16 siz);
 
-uint16  XCrypt(void *buf, uint16 siz, uint16 seed);
+uint16  XCrypt(void *buf, uint16 siz);
 int     takeEnum(const char **tab, const char *text);
 uint16  chkSum(void *m, uint16 n);
 char   *mergeExt(char *buf, const char *name, const char *ext);