Change decoder/encoder API to provide decode/encode functions with a read callback function.

1 files changed, 21 insertions, 13 deletions

diff --git a/encoder.h b/encoder.h
index f68d51c..d000ffc 100644
--- a/encoder.h
+++ b/encoder.h
@@ -4,23 +4,40 @@
 #include <boost/iostreams/concepts.hpp>
 #include <boost/iostreams/operations.hpp>
 #include <boost/shared_ptr.hpp>
+#include <boost/function.hpp>
 
 #include <iostream>
 #include <string>
 
 class EncoderBase {
+	friend class EncoderFilter;
+	
+	protected:
+		typedef boost::function<std::size_t (char*, std::size_t)> ReadFunc;
+		
+		virtual size_t encode(ReadFunc read, uint8_t *output, size_t output_size) = 0;
+		
 	public:
 		typedef boost::shared_ptr<EncoderBase> p;
 		virtual ~EncoderBase() {}
-		
-		virtual size_t encode(const uint8_t *input, size_t input_size, uint8_t *output, size_t output_size) = 0;
-		virtual size_t flush(uint8_t *output, size_t output_size) = 0;
 };
 
 //! Input filter to hold an encoder in a filter chain.
 class EncoderFilter : public boost::iostreams::multichar_input_filter {
 	private:
 		EncoderBase::p encoder;
+		
+		//! Functor binding a source to a read function.
+		template<class T>
+		struct ReadFunc {
+			T& s;
+			
+			ReadFunc(T& s_) : s(s_) {}
+			
+			std::size_t operator()(char* buf, std::size_t buf_size) {
+				return boost::iostreams::read(s, buf, buf_size);
+			}
+		};
 	
 	public:
 		typedef boost::shared_ptr<EncoderFilter> p;
@@ -28,16 +45,7 @@ class EncoderFilter : public boost::iostreams::multichar_input_filter {
 		
 		template<typename Source>
 		std::streamsize read(Source& src, char *s, std::streamsize n) {
-			char src_data[0x2000];
-			std::streamsize src_read = boost::iostreams::read(src, src_data, 0x2000);
-			if(src_read < 0)
-				src_read = 0;
-			std::streamsize size = encoder->encode((const uint8_t*)src_data, src_read, (uint8_t*)s, n);
-			// no more data, flush encoder
-			if(src_read == 0 && size == 0) {
-				size = encoder->flush((uint8_t*)s, n);
-			}
-			return size;
+			return encoder->encode(ReadFunc<Source>(src), (uint8_t*)s, n);
 		};
 };