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

6 files changed, 77 insertions, 25 deletions

diff --git a/decoder.h b/decoder.h
index 9faabc1..d58dcf1 100644
--- a/decoder.h
+++ b/decoder.h
@@ -4,21 +4,39 @@
 #include <boost/iostreams/concepts.hpp>
 #include <boost/iostreams/operations.hpp>
 #include <boost/shared_ptr.hpp>
+#include <boost/function.hpp>
 
 #include <string>
 
 class DecoderBase {
+	friend class DecoderFilter;
+	
+	protected:
+		typedef boost::function<std::size_t (char*, std::size_t)> ReadFunc;
+		
+		virtual size_t decode(ReadFunc read, uint8_t *output, size_t output_size) = 0;
+	
 	public:
 		typedef boost::shared_ptr<DecoderBase> p;
-		virtual size_t decode(const uint8_t *input, size_t input_size, uint8_t *output, size_t output_size) = 0;
 		virtual ~DecoderBase() {}
-		
 };
 
 //! Input filter to hold a decoder in a filter chain.
 class DecoderFilter : public boost::iostreams::multichar_input_filter {
 	private:
 		DecoderBase::p decoder;
+		
+		//! 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<DecoderFilter> p;
@@ -26,11 +44,7 @@ class DecoderFilter : 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;
-			return decoder->decode((const uint8_t*)src_data, src_read, (uint8_t*)s, n);
+			return decoder->decode(ReadFunc<Source>(src), (uint8_t*)s, n);
 		}
 };
 
diff --git a/decoders/mpg123_decoder.cpp b/decoders/mpg123_decoder.cpp
index 0c2629f..0618320 100644
--- a/decoders/mpg123_decoder.cpp
+++ b/decoders/mpg123_decoder.cpp
@@ -48,3 +48,11 @@ size_t DecoderMpg123::decode(const uint8_t *input, size_t input_size, uint8_t *o
 
 	return output_written;
 }
+
+size_t DecoderMpg123::decode(ReadFunc read, uint8_t *output, size_t output_size) {
+	char src_data[0x2000];
+	std::streamsize src_read = read(src_data, 0x2000);
+	if(src_read < 0)
+		src_read = 0;
+	return decode((const uint8_t*)src_data, src_read, (uint8_t*)output, output_size);
+}
diff --git a/decoders/mpg123_decoder.h b/decoders/mpg123_decoder.h
index 46f9e4c..5a637af 100644
--- a/decoders/mpg123_decoder.h
+++ b/decoders/mpg123_decoder.h
@@ -8,11 +8,15 @@
 class DecoderMpg123 : public DecoderBase {
 	private:
 		mpg123_handle *handle;
-
+		
+		size_t decode(const uint8_t *input, size_t input_size, uint8_t *output, size_t output_size);
+	
+	protected:
+		virtual size_t decode(ReadFunc read, uint8_t *output, size_t output_size);
+	
 	public:
 		DecoderMpg123();
 		~DecoderMpg123();
-		size_t decode(const uint8_t *input, size_t input_size, uint8_t *output, size_t output_size);
 };
 
 #endif
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);
 		};
 };
 
diff --git a/encoders/lame_encoder.cpp b/encoders/lame_encoder.cpp
index 125ee5e..7bf2ebc 100644
--- a/encoders/lame_encoder.cpp
+++ b/encoders/lame_encoder.cpp
@@ -22,3 +22,17 @@ size_t EncoderLame::encode(const uint8_t *input, size_t input_size, uint8_t *out
 size_t EncoderLame::flush(uint8_t *output, size_t output_size) {
 	return lame_encode_flush(gfp, output, output_size);
 }
+
+size_t EncoderLame::encode(ReadFunc read, uint8_t *output, size_t output_size) {
+	char src_data[0x2000];
+	std::streamsize src_read = read(src_data, 0x2000);
+	if(src_read < 0)
+		src_read = 0;
+	std::streamsize size = encode((const uint8_t*)src_data, src_read, (uint8_t*)output, output_size);
+	// no more data, flush encoder
+	if(src_read == 0 && size == 0) {
+		size = flush((uint8_t*)output, output_size);
+	}
+	return size;
+	
+}
\ No newline at end of file
diff --git a/encoders/lame_encoder.h b/encoders/lame_encoder.h
index 1843361..98ebc9f 100644
--- a/encoders/lame_encoder.h
+++ b/encoders/lame_encoder.h
@@ -8,12 +8,16 @@
 class EncoderLame : public EncoderBase {
 	private:
 		lame_global_flags *gfp;
-
+		
+		size_t encode(const uint8_t *input, size_t input_size, uint8_t *output, size_t output_size);
+		size_t flush(uint8_t *output, size_t output_size);
+	
+	protected:
+		virtual size_t encode(ReadFunc read, uint8_t *output, size_t output_size);
+	
 	public:
 		EncoderLame();
 		~EncoderLame();
-		size_t encode(const uint8_t *input, size_t input_size, uint8_t *output, size_t output_size);
-		size_t flush(uint8_t *output, size_t output_size);
 };
 
 #endif