Make the crypto_stream_salsa20 implementation switchable at compile-time

configure.ac

@@ -303,6 +303,7 @@ AC_CONFIG_FILES([Makefile
                  src/libsodium/include/Makefile
                  src/libsodium/include/sodium/version.h
                  src/libsodium/include/sodium/crypto_scalarmult_curve25519.h
+                 src/libsodium/include/sodium/crypto_stream_salsa20.h
                  test/default/Makefile
                  test/Makefile
                  ])

src/libsodium/crypto_stream/salsa20/ref/api.h

@@ -1,10 +1,8 @@
 
 #include "crypto_stream_salsa20.h"
 
-#define crypto_stream crypto_stream_salsa20
-#define crypto_stream_xor crypto_stream_salsa20_xor
-#define crypto_stream_KEYBYTES crypto_stream_salsa20_KEYBYTES
-#define crypto_stream_NONCEBYTES crypto_stream_salsa20_NONCEBYTES
-#define crypto_stream_PRIMITIVE "salsa20"
-#define crypto_stream_IMPLEMENTATION crypto_stream_salsa20_IMPLEMENTATION
-#define crypto_stream_VERSION crypto_stream_salsa20_VERSION
+#define crypto_stream_salsa20_implementation_name \
+    crypto_stream_salsa20_ref_implementation_name
+
+#define crypto_stream crypto_stream_salsa20_ref
+#define crypto_stream_xor crypto_stream_salsa20_ref_xor

src/libsodium/include/Makefile.am

@@ -55,6 +55,7 @@ SODIUM_EXPORT = \
 
 EXTRA_SRC = $(SODIUM_EXPORT) \
 	sodium/crypto_scalarmult_curve25519.h.in \
+	sodium/crypto_stream_salsa20.h.in \
 	sodium/version.h.in
 
 nobase_include_HEADERS = $(SODIUM_EXPORT)

src/libsodium/include/sodium/crypto_stream_salsa20.h

@@ -24,6 +24,11 @@ int crypto_stream_salsa20(unsigned char *,unsigned long long,const unsigned char
 SODIUM_EXPORT
 int crypto_stream_salsa20_xor(unsigned char *,const unsigned char *,unsigned long long,const unsigned char *,const unsigned char *);
 
+#if 1
+# define crypto_stream_salsa20_ref crypto_stream_salsa20
+# define crypto_stream_salsa20_ref_xor crypto_stream_salsa20_xor
+#endif
+
 #ifdef __cplusplus
 }
 #endif

src/libsodium/include/sodium/crypto_stream_salsa20.h.in

@@ -0,0 +1,39 @@
+#ifndef crypto_stream_salsa20_H
+#define crypto_stream_salsa20_H
+
+/*
+ *  WARNING: This is just a stream cipher. It is NOT authenticated encryption.
+ *  While it provides some protection against eavesdropping, it does NOT
+ *  provide any security against active attacks.
+ *  Unless you know what you're doing, what you are looking for is probably
+ *  the crypto_box functions.
+ */
+
+#include "export.h"
+
+#define crypto_stream_salsa20_KEYBYTES 32U
+#define crypto_stream_salsa20_NONCEBYTES 8U
+
+#ifdef __cplusplus
+extern "C" {
+#endif
+
+SODIUM_EXPORT
+int crypto_stream_salsa20(unsigned char *,unsigned long long,const unsigned char *,const unsigned char *);
+
+SODIUM_EXPORT
+int crypto_stream_salsa20_xor(unsigned char *,const unsigned char *,unsigned long long,const unsigned char *,const unsigned char *);
+
+#if 1    
+# define crypto_stream_salsa20_ref crypto_stream_salsa20
+# define crypto_stream_salsa20_ref_xor crypto_stream_salsa20_xor
+#endif    
+
+#ifdef __cplusplus
+}
+#endif
+
+#define crypto_stream_salsa20_ref crypto_stream_salsa20
+#define crypto_stream_salsa20_ref_xor crypto_stream_salsa20_xor
+
+#endif