Use a filtering_istream with custom filters to chain file -> decoder -> encoder.

7 files changed, 61 insertions, 25 deletions

diff --git a/decoder.h b/decoder.h
index b4dcdb6..a7aaad9 100644
--- a/decoder.h
+++ b/decoder.h
@@ -5,6 +5,8 @@
 #include <boost/function.hpp>
 #include <boost/functional/factory.hpp>
 #include <boost/functional/value_factory.hpp>
+#include <boost/iostreams/concepts.hpp>
+#include <boost/iostreams/operations.hpp>
 
 #include <string>
 
@@ -13,6 +15,21 @@ class DecoderBase {
 		virtual size_t decode(const uint8_t *input, size_t input_size, uint8_t *output, size_t output_size) = 0;
 };
 
+class DecoderFilter : public boost::iostreams::multichar_input_filter {
+	private:
+		DecoderBase& decoder;
+	public:
+		DecoderFilter(DecoderBase& decoder_) : decoder(decoder_) {};
+		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);
+		};
+};
+
 namespace decoder {
 	void init();
 	DecoderBase *get_decoder(const std::string& name);
diff --git a/encoder.h b/encoder.h
index 9949b52..7021cdc 100644
--- a/encoder.h
+++ b/encoder.h
@@ -5,15 +5,32 @@
 #include <boost/function.hpp>
 #include <boost/functional/factory.hpp>
 #include <boost/functional/value_factory.hpp>
+#include <boost/iostreams/concepts.hpp>
+#include <boost/iostreams/operations.hpp>
 
 #include <string>
 
 class EncoderBase {
 	public:
-		virtual size_t encode(uint8_t *input, size_t input_size, uint8_t *output, size_t output_size) = 0;
+		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;
 };
 
+class EncoderFilter : public boost::iostreams::multichar_input_filter {
+	private:
+		EncoderBase& encoder;
+	public:
+		EncoderFilter(EncoderBase& encoder_) : encoder(encoder_) {};
+		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 encoder.encode((const uint8_t*)src_data, src_read, (uint8_t*)s, n);
+		};
+};
+
 namespace encoder {
 	void init();
 	EncoderBase *get_encoder(const std::string& name);
diff --git a/encoders/lame_encoder.cpp b/encoders/lame_encoder.cpp
index 4cbfc9c..125ee5e 100644
--- a/encoders/lame_encoder.cpp
+++ b/encoders/lame_encoder.cpp
@@ -15,12 +15,10 @@ EncoderLame::~EncoderLame() {
 	lame_close(gfp);
 }
 
-size_t EncoderLame::encode(uint8_t *input, size_t input_size, uint8_t *output, size_t output_size) {
-	size_t size = lame_encode_buffer_interleaved(gfp, (short*)input, input_size / 4, output, output_size);
-	return size;
+size_t EncoderLame::encode(const uint8_t *input, size_t input_size, uint8_t *output, size_t output_size) {
+	return lame_encode_buffer_interleaved(gfp, (short*)input, input_size / 4, output, output_size);
 }
 
 size_t EncoderLame::flush(uint8_t *output, size_t output_size) {
-	size_t size = lame_encode_flush(gfp, output, output_size);
-	return size;
+	return lame_encode_flush(gfp, output, output_size);
 }
diff --git a/encoders/lame_encoder.h b/encoders/lame_encoder.h
index 47f9666..1843361 100644
--- a/encoders/lame_encoder.h
+++ b/encoders/lame_encoder.h
@@ -12,7 +12,7 @@ class EncoderLame : public EncoderBase {
 	public:
 		EncoderLame();
 		~EncoderLame();
-		size_t encode(uint8_t *input, size_t input_size, uint8_t *output, size_t output_size);
+		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);
 };
 
diff --git a/music.cpp b/music.cpp
index ec2f537..9892526 100644
--- a/music.cpp
+++ b/music.cpp
@@ -132,16 +132,15 @@ void MusicTrack::render(HTTP::Connection::p req, HTTPResponse& res) {
 	Tag *t = new ID3Tag(path.string());
 	delete t;
 
-	fs::ifstream is(path, std::ios::binary | std::ios::in);
-
 	if(req->args.count("decoder") && req->args.count("encoder")) {
 		DecoderBase *d = decoder::get_decoder(req->args["decoder"]);
 		EncoderBase *e = encoder::get_encoder(req->args["encoder"]);
-		Transcoder t(is, res, *d, *e);
+		Transcoder t(path.string(), res, *d, *e);
 		t.run();
 		delete d;
 		delete e;
 	} else {
+		fs::ifstream is(path, std::ios::in | std::ios::binary);
 		is.seekg(0, std::ios::end);
 		res.add_header("content-length", boost::str(boost::format("%d") % is.tellg()));
 		is.seekg(0, std::ios::beg);
diff --git a/transcode.cpp b/transcode.cpp
index 249ffb3..5244627 100644
--- a/transcode.cpp
+++ b/transcode.cpp
@@ -1,20 +1,25 @@
 #include "transcode.h"
 
-Transcoder::Transcoder(std::istream& i, HTTPResponse& r, DecoderBase& d, EncoderBase& e) : is(i), res(r), decoder(d), encoder(e) {
+#include <boost/iostreams/device/file.hpp>
+#include <boost/iostreams/filtering_stream.hpp>
+
+Transcoder::Transcoder(std::string p, HTTPResponse& r, DecoderBase& d, EncoderBase& e) : path(p), res(r), decoder(d), encoder(e) {
 }
 
 void Transcoder::run() {
+	const std::streamsize buffer_size = 0x1000;
+	boost::iostreams::file_source is(path, std::ios::in | std::ios::binary);
+	boost::iostreams::filtering_istream s;
+	s.push(EncoderFilter(encoder), buffer_size);
+	s.push(DecoderFilter(decoder), buffer_size);
+	s.push(is, buffer_size);
+
 	char data[0x1000];
-	bool encoding_fone = false;
-	while(!encoding_fone) {
-		size_t decoded_size = 0;
-		char decoded_data[0x1000];
-		if(is.good()) {
-			is.read(data, 0x1000);
-			decoded_size = decoder.decode((uint8_t*)data, is.gcount(), (uint8_t*)decoded_data, 0x1000);
-		}
-		char encoded_data[0x1000];
-		size_t encoded_size = encoder.encode((uint8_t*)decoded_data, decoded_size, (uint8_t*)encoded_data, 0x1000);
-		res.write(encoded_data, encoded_size);
+	std::streamsize size = 1;
+	while(size) {
+		s.read(data, 0x1000);
+		size = s.gcount();
+		if(size > 0)
+			res.write(data, size);
 	}
 }
diff --git a/transcode.h b/transcode.h
index 2a63b17..d0e781d 100644
--- a/transcode.h
+++ b/transcode.h
@@ -5,17 +5,17 @@
 #include "encoder.h"
 #include "http.h"
 
-#include <iostream>
+#include <string>
 
 class Transcoder {
 	private:
-		std::istream& is;
+		std::string path;
 		HTTPResponse& res;
 		DecoderBase& decoder;
 		EncoderBase& encoder;
 
 	public:
-		Transcoder(std::istream& i, HTTPResponse& r, DecoderBase& d, EncoderBase& e);
+		Transcoder(std::string p, HTTPResponse& r, DecoderBase& d, EncoderBase& e);
 		void run();
 };