latest SDK

foobar2000/helpers/input_fix_seeking.h

@@ -0,0 +1,65 @@
+#pragma once
+
+#include "duration_counter.h"
+
+// Wrapper to implement input_flag_allow_inaccurate_seeking semantics with decoders that do not implement seeking properly.
+// If input_flag_allow_inaccurate_seeking is not specified, brute force seeking is used.
+template<typename base_t>
+class input_fix_seeking : public base_t {
+public:
+	input_fix_seeking() : m_active() {}
+
+	void decode_initialize(unsigned p_flags,abort_callback & p_abort) {
+		base_t::decode_initialize( p_flags, p_abort );
+		m_active = ( p_flags & input_flag_allow_inaccurate_seeking ) == 0;
+		m_position = 0;
+		m_decodeFrom = 0;
+	}
+
+	void decode_initialize(t_uint32 p_subsong,unsigned p_flags,abort_callback & p_abort) {
+		base_t::decode_initialize( p_subsong, p_flags, p_abort );
+		m_active = ( p_flags & input_flag_allow_inaccurate_seeking ) == 0;
+		m_position = 0;
+	}
+
+	bool decode_run(audio_chunk & p_chunk,abort_callback & p_abort) {
+		if ( ! m_active ) {
+			return base_t::decode_run ( p_chunk, p_abort );
+		}
+		for ( ;; ) {
+			p_abort.check();
+			if (! base_t::decode_run( p_chunk, p_abort ) ) return false;
+
+			double p = m_position.query();
+			m_position += p_chunk;
+			if ( m_decodeFrom > p ) {
+				auto skip = audio_math::time_to_samples( m_decodeFrom - p, p_chunk.get_sample_rate() );
+				if ( skip >= p_chunk.get_sample_count() ) continue;
+				if ( skip > 0 ) {
+					p_chunk.skip_first_samples( (size_t) skip );
+				}
+			}
+			return true;
+		}
+	}
+
+	void decode_seek(double p_seconds,abort_callback & p_abort) {
+		if ( m_active ) {
+			if ( ! this->decode_can_seek() ) throw exception_io_object_not_seekable();
+			m_decodeFrom = p_seconds;
+			if ( m_decodeFrom < m_position.query() ) {
+				base_t::decode_seek(0, p_abort); m_position.reset();
+			}
+		} else {
+			base_t::decode_seek(p_seconds, p_abort);
+		}
+	}
+
+	bool decode_run_raw(audio_chunk & p_chunk, mem_block_container & p_raw, abort_callback & p_abort) {
+		throw pfc::exception_not_implemented(); // shitformats that need this class are not likely to care
+	}
+private:
+	bool m_active;
+	duration_counter m_position;
+	double m_decodeFrom;
+};