From b7a9efe914f9dc1d1fa1f87d0a4b7c26a59d5e7c Mon Sep 17 00:00:00 2001
From: Stephen Crane <jscrane@gmail.com>
Date: Fri, 14 Nov 2014 18:27:54 +0000
Subject: [PATCH] checkpointing utilities

---
 checkpoint.cpp | 29 +++++++++++++++++++++++++++++
 checkpoint.h   |  8 ++++++++
 r65emu.h       |  1 +
 3 files changed, 38 insertions(+)
 create mode 100644 checkpoint.cpp
 create mode 100644 checkpoint.h

diff --git a/checkpoint.cpp b/checkpoint.cpp
new file mode 100644
index 0000000..11f211f
--- /dev/null
+++ b/checkpoint.cpp
@@ -0,0 +1,29 @@
+#include <SD.h>
+#include "sdtape.h"
+#include "checkpoint.h"
+#include "hardware.h"
+
+static char buf[32];
+static char chkpt[] = { "CHKPOINT" };
+static int cpid = 0;
+
+const char *checkpoint(sdtape &tape, const char *dir) {
+	tape.stop();
+	snprintf(buf, sizeof(buf), "%s%s.%03d", dir, chkpt, cpid++);
+	File file = SD.open(buf, O_WRITE | O_CREAT | O_TRUNC);
+	hardware_checkpoint(file);
+	file.close();
+	tape.start(dir);
+	return buf;
+}
+
+void restore(sdtape &tape, const char *dir, const char *filename) {
+	tape.stop();
+	snprintf(buf, sizeof(buf), "%s%s", dir, filename);
+	File file = SD.open(buf, O_READ);
+	hardware_restore(file);
+	file.close();
+	int n = sscanf(buf + strlen(dir), "%[A-Z0-9].%d", chkpt, &cpid);
+	cpid = (n == 1)? 0: cpid+1;
+	tape.start(dir);
+}
diff --git a/checkpoint.h b/checkpoint.h
new file mode 100644
index 0000000..7297ae9
--- /dev/null
+++ b/checkpoint.h
@@ -0,0 +1,8 @@
+#ifndef __CHECKPOINT_H__
+#define __CHECKPOINT_H__
+
+// utility checkpoint functions
+const char *checkpoint(sdtape &tape, const char *dir);
+void restore(sdtape &tape, const char *dir, const char *filename);
+
+#endif
diff --git a/r65emu.h b/r65emu.h
index ed8eb9c..71ef289 100644
--- a/r65emu.h
+++ b/r65emu.h
@@ -13,5 +13,6 @@
 #include "sdtape.h"
 #include "timed.h"
 #include "hardware.h"
+#include "checkpoint.h"
 
 #endif