Modularize preloading with a sound reader, so the !big logic

in RageSound can go away

stepmania/src/RageSoundReader_Preload.cpp

@@ -0,0 +1,140 @@
+#include "global.h"
+#include "RageSoundReader_Preload.h"
+
+const int channels = 2;
+const int samplesize = 2 * channels; /* 16-bit */
+const int samplerate = 44100;
+
+const int max_prebuf_size = 1024*256*10;
+
+int SoundReader_Preload::total_samples() const
+{
+	return buf.get().size() / samplesize;
+}
+
+bool SoundReader_Preload::Open(SoundReader *source)
+{
+	/* Check the length, and see if we think it'll fit in the buffer. */
+	int len = source->GetLength_Fast();
+	if(len != -1)
+	{
+		float secs = len / 1000.f;
+
+		int pcmsize = int(secs * samplerate * samplesize); /* seconds -> bytes */
+		if(pcmsize > max_prebuf_size)
+			return false; /* Don't bother trying to preload it. */
+
+		buf.get_owned().reserve(pcmsize);
+	}
+
+	while(1) {
+		char buffer[1024];
+		int cnt = source->Read(buffer, sizeof(buffer));
+
+		if(cnt < 0) {
+			/* XXX untested */
+			SetError(source->GetError());
+			return false;
+		}
+
+		if(!cnt) break; /* eof */
+
+		/* Add the buffer. */
+		buf.get_owned().append(buffer, buffer+cnt);
+
+		if(buf.get_owned().size() > max_prebuf_size)
+			return false; /* too big */
+	}
+
+	position = 0;
+	return true;
+}
+
+int SoundReader_Preload::GetLength() const
+{
+	return int(float(total_samples()) * 1000.f / samplerate);
+}
+
+int SoundReader_Preload::GetLength_Fast() const
+{
+	return GetLength();
+}
+
+int SoundReader_Preload::SetPosition_Accurate(int ms)  
+{
+	const int sample = int((ms / 1000.0f) * samplerate);
+	position = sample * samplesize;
+
+	if(position >= int(buf.get().size()))
+		position = 0;
+
+	return position;
+}
+
+int SoundReader_Preload::SetPosition_Fast(int ms)
+{
+	return SetPosition_Accurate(ms); 
+}
+
+int SoundReader_Preload::Read(char *buffer, unsigned len)
+{
+	const unsigned bytes_avail = buf.get().size() - position;
+
+	len = min(len, bytes_avail);
+	memcpy(buffer, buf.get().data()+position, len);
+	position += len;
+	
+	return len;
+}
+
+SoundReader *SoundReader_Preload::Copy() const
+{
+	return new SoundReader_Preload(*this);
+}
+
+rc_string::rc_string()
+{
+	buf = new string;
+	cnt = new int(1);
+}
+
+rc_string::rc_string(const rc_string &rhs)
+{
+	buf = rhs.buf;
+	cnt = rhs.cnt;
+	(*cnt)++;
+}
+
+rc_string::~rc_string()
+{
+	(*cnt)--;
+	if(!*cnt)
+	{
+		delete buf;
+		delete cnt;
+	}
+}
+
+string &rc_string::get_owned()
+{
+	if(*cnt != 1)
+	{
+		(*cnt)--;
+		buf = new string(*buf);
+		cnt = new int(1);
+	}
+
+	return *buf;
+}
+
+const string &rc_string::get() const
+{
+	return *buf;
+}
+
+/*
+-----------------------------------------------------------------------------
+ Copyright (c) 2003 by the person(s) listed below.  All rights reserved.
+	Glenn Maynard
+-----------------------------------------------------------------------------
+*/

stepmania/src/RageSoundReader_Preload.h

@@ -0,0 +1,51 @@
+#ifndef RAGE_SOUND_READER_PRELOAD
+#define RAGE_SOUND_READER_PRELOAD
+
+#include "RageSoundReader.h"
+
+/* This reader simply precaches all of the data from another reader. This
+ * reduces CPU usage for sounds that are played several times at once. */
+
+/* Trivial wrapper to refcount strings, since std::string is not always
+ * refcounted.  Without this, Copy() is very slow. */
+class rc_string
+{
+	mutable string *buf;
+	mutable int *cnt;
+
+public:
+	rc_string();
+	rc_string(const rc_string &rhs);
+	~rc_string();
+	string &get_owned();
+	const string &get() const;
+};
+
+class SoundReader_Preload: public SoundReader {
+	rc_string buf;
+
+	/* Bytes: */
+	int position;
+
+	int total_samples() const;
+
+public:
+	/* This will throw a nonfatal exception if this sound isn't
+	 * suitable for preloading. */
+	bool Open(SoundReader *source);
+	int GetLength() const;
+	int GetLength_Fast() const;
+	int SetPosition_Accurate(int ms);
+	int SetPosition_Fast(int ms);
+	int Read(char *buf, unsigned len);
+	SoundReader *Copy() const;
+	~SoundReader_Preload() { }
+};
+
+#endif
+/*
+-----------------------------------------------------------------------------
+ Copyright (c) 2003 by the person(s) listed below.  All rights reserved.
+	Glenn Maynard
+-----------------------------------------------------------------------------
+*/