[Performous-commit] Lasse Karkkainen : Add da::accumulator, a helper useful for summing the results of independent chains.

[Lasse Kärkkäi. <tr...@us...>]

Module: performous
Branch: master
Commit: 835b6cc355384926978fde665c1c7f404ab50b47

Author: Lasse Karkkainen <tro...@tr...>
Date:   Sat Jul 25 05:41:55 2009 +0300

Add da::accumulator, a helper useful for summing the results of independent chains.
Add .samples() for pcm_data, doing the often needed multiplication channels * frames.

---

 libs/libda/include/libda/audio.hpp |    1 +
 libs/libda/include/libda/mixer.hpp |   30 ++++++++++++++++++++++++++++--
 2 files changed, 29 insertions(+), 2 deletions(-)

diff --git a/libs/libda/include/libda/audio.hpp b/libs/libda/include/libda/audio.hpp
index 8f95601..2fa7187 100644
--- a/libs/libda/include/libda/audio.hpp
+++ b/libs/libda/include/libda/audio.hpp
@@ -63,6 +63,7 @@ namespace da {
 		};
 		iter_by_ch begin(std::size_t ch) { return iter_by_ch(rawbuf, ch, channels); }
 		iter_by_ch end(std::size_t ch) { return iter_by_ch(rawbuf, ch, channels) + frames; }
+		std::size_t samples() const { return channels * frames; }
 	};
 
 	struct settings;
diff --git a/libs/libda/include/libda/mixer.hpp b/libs/libda/include/libda/mixer.hpp
index 3408e3d..2153853 100644
--- a/libs/libda/include/libda/mixer.hpp
+++ b/libs/libda/include/libda/mixer.hpp
@@ -43,7 +43,7 @@ namespace da {
 		void add(callback_t const& cb) {
 			streams.push_back(cb);
 		}
-		/** Calls every scream in the chain and removes those that return false. **/
+		/** Calls every stream in the chain and removes those that return false. **/
 		bool operator()(pcm_data& data) {
 			streams_t::iterator wr = streams.begin();
 			for (streams_t::iterator it = wr; it != streams.end(); ++it) {
@@ -63,9 +63,35 @@ namespace da {
 		}
 	}
 
+	class accumulate: boost::noncopyable {
+	  public:
+		typedef std::vector<callback_t> streams_t;
+		accumulate() {}
+		void add(callback_t const& cb) {
+			streams.push_back(cb);
+		}
+		/** Calls every stream in the chain and removes those that return false, summing the results. **/
+		bool operator()(pcm_data& data) {
+			std::vector<sample_t> buffer(data.samples());
+			pcm_data accumbuf(&buffer[0], data.frames, data.channels, data.rate);
+			streams_t::iterator wr = streams.begin();
+			for (streams_t::iterator it = wr; it != streams.end(); ++it) {
+				if ((*it)(accumbuf)) *wr++ = *it;
+				for (std::size_t i = 0; i < buffer.size(); ++i) {
+					data.rawbuf[i] += buffer[i];
+					buffer[i] = 0.0f;
+				}
+			}
+			if (wr != streams.end()) streams.erase(wr, streams.end());
+			return !streams.empty();
+		}
+		streams_t streams;
+	  private:
+	};
+
 	class buffer: boost::noncopyable {
 	  public:
-		explicit buffer(size_t s): m_data(s) {}
+		explicit buffer(std::size_t s): m_data(s) {}
 		sample_t* begin() { return &m_data[0]; }
 		sample_t* end() { return begin() + m_data.size(); }
 	  private: