medfall

commit fd7ebc309c1b972ebc92484302553e84ad8f23fd
parent 019addb26c500bc68ed344efa94fc5bbcea09749
Author: Michael Savage <mikejsavage@gmail.com>
Date:   Thu Dec 22 22:27:09 +0200

New ReadStream/WriteStream implementation

Diffstat:
stream.h
 | 
86
+++++++++++++++++++++++++++++++++++++++++++++++++++++--------------------------
1 file changed, 58 insertions(+), 28 deletions(-)
diff --git a/stream.h b/stream.h
@@ -1,19 +1,16 @@
-// TODO: need to come up with something for writers though
-
-#ifndef _STREAM_H_
-#define _STREAM_H_
+#pragma once
 
 #include "intrinsics.h"
 #include "platform_inline.h"
 
 struct ReadStream {
 	ReadStream( char * buf, size_t len ) {
-		ptr = buf;
+		cursor = buf;
 		one_past_end = buf + len;
 		ok = true;
 	}
 
-	char * ptr;
+	char * cursor;
 	char * one_past_end;
 	bool ok;
 };
@@ -21,13 +18,17 @@ struct ReadStream {
 struct WriteStream {
 	WriteStream( char * buf, size_t len ) {
 		start = buf;
-		ptr = buf;
+		cursor = buf;
 		one_past_end = buf + len;
 		ok = true;
 	}
 
+	size_t len() const {
+		return checked_cast< size_t >( cursor - start );
+	}
+
 	char * start;
-	char * ptr;
+	char * cursor;
 	char * one_past_end;
 	bool ok;
 };
@@ -38,30 +39,61 @@ static bool cpu_is_little_endian() {
 	return c[ 0 ] == 1;
 }
 
+struct StreamSerialiser {
+	StreamSerialiser( WriteStream * s ) {
+		stream = s;
+	}
+
+	template< typename T >
+	void operator()( const T & x ) {
+		ASSERT( cpu_is_little_endian() );
+		if( !stream->ok || checked_cast< size_t >( stream->one_past_end - stream->cursor ) < sizeof( T ) ) {
+			stream->ok = false;
+			return;
+		}
+		memcpy( stream->cursor, &x, sizeof( T ) );
+		stream->cursor += sizeof( T );
+	}
+
+	WriteStream * stream;
+};
+
+struct StreamDeserialiser {
+	StreamDeserialiser( ReadStream * s ) {
+		stream = s;
+	}
+
+	template< typename T >
+	void operator()( T & x ) {
+		ASSERT( cpu_is_little_endian() );
+		if( !stream->ok || checked_cast< size_t >( stream->one_past_end - stream->cursor ) < sizeof( T ) ) {
+			stream->ok = false;
+			x = T();
+			return;
+		}
+		memcpy( &x, stream->cursor, sizeof( T ) );
+		stream->cursor += sizeof( T );
+	}
+
+	ReadStream * stream;
+};
+
+template< typename T >
+inline void read( ReadStream * stream, T * x ) {
+	visit( *x, StreamDeserialiser( stream ) );
+}
+
+template< typename T >
+inline void write( WriteStream * stream, const T & x ) {
+	visit( x, StreamSerialiser( stream ) );
+}
+
 #define DEF_READ_WRITE( T ) \
-	inline void read( ReadStream * stream, T * x ) { \
-		ASSERT( cpu_is_little_endian() ); \
-		if( !stream->ok || checked_cast< size_t >( stream->one_past_end - stream->ptr ) < sizeof( T ) ) { \
-			stream->ok = false; \
-			*x = T(); \
-		} \
-		memcpy( x, stream->ptr, sizeof( T ) ); \
-		stream->ptr += sizeof( T ); \
-	} \
 	inline T read_##T( ReadStream * stream ) { \
 		T x; \
 		read( stream, &x ); \
 		return x; \
 	} \
-	inline void write( WriteStream * stream, const T & x ) { \
-		ASSERT( cpu_is_little_endian() ); \
-		if( !stream->ok || checked_cast< size_t >( stream->one_past_end - stream->ptr ) < sizeof( T ) ) { \
-			stream->ok = false; \
-			return; \
-		} \
-		memcpy( stream->ptr, &x, sizeof( T ) ); \
-		stream->ptr += sizeof( T ); \
-	} \
 	inline void write_##T( WriteStream * stream, const T & x ) { \
 		write( stream, x ); \
 	}
@@ -78,5 +110,3 @@ DEF_READ_WRITE( float )
 DEF_READ_WRITE( double )
 
 #undef DEF_READ_WRITE
-
-#endif // _STREAM_H_