From cd9744757cd1d1d0ea376758173820c79e03c4b0 Mon Sep 17 00:00:00 2001
From: Stephen Crane <jscrane@gmail.com>
Date: Sun, 26 Oct 2014 17:54:01 +0000
Subject: [PATCH] sdtape abstraction

---
 r65emu.h   |  1 +
 sdtape.cpp | 52 ++++++++++++++++++++++++++++++++++++++++++++++++++++
 sdtape.h   | 21 +++++++++++++++++++++
 3 files changed, 74 insertions(+)
 create mode 100644 sdtape.cpp
 create mode 100644 sdtape.h

diff --git a/r65emu.h b/r65emu.h
index 47b7166..0e41628 100644
--- a/r65emu.h
+++ b/r65emu.h
@@ -10,6 +10,7 @@
 #include "ps2drv.h"
 #include "utftdisplay.h"
 #include "keyboard.h"
+#include "sdtape.h"
 #include "hardware.h"
 
 #endif
diff --git a/sdtape.cpp b/sdtape.cpp
new file mode 100644
index 0000000..6faec88
--- /dev/null
+++ b/sdtape.cpp
@@ -0,0 +1,52 @@
+#include <SD.h>
+#include "sdtape.h"
+
+static File file, dir;
+
+void sdtape::start(const char *programs)
+{
+	dir = SD.open(programs);
+}
+
+void sdtape::stop()
+{
+	file.close();
+}
+
+bool sdtape::more()
+{
+	if (_pos >= _len) {
+		_pos = 0;
+		_len = file.read(_buf, sizeof(_buf));
+
+		if (_len == 0) {
+			file.close();
+			return false;	// eof
+		}
+	}
+	return true;
+}
+
+const char *sdtape::advance() {
+	bool rewound = false;
+	file.close();
+	while (true) {
+		file = dir.openNextFile();
+		if (file) {
+			if (file.isDirectory())
+				file.close();
+			else
+				break;
+		} else if (!rewound) {
+			dir.rewindDirectory();
+			rewound = true;
+		} else
+			return 0;
+	}
+	return file.name();
+}
+
+const char *sdtape::rewind() {
+	dir.rewindDirectory();
+	return advance();
+}
diff --git a/sdtape.h b/sdtape.h
new file mode 100644
index 0000000..6d8146b
--- /dev/null
+++ b/sdtape.h
@@ -0,0 +1,21 @@
+#ifndef _SDTAPE_H
+#define _SDTAPE_H
+
+class sdtape {
+public:
+	const char *advance();
+	const char *rewind();
+
+	void start(const char *);
+	void stop();
+	
+	sdtape(): _pos(0), _len(0) {}
+
+	byte read() { return _buf[_pos++]; }
+	bool more();
+
+private:
+	unsigned int _pos, _len;
+	byte _buf[128];
+};
+#endif