lazy-parse the version and startTime

6 files changed, 234 insertions, 75 deletions

diff --git a/dslog/DseventsReader.java b/dslog/DseventsReader.java
index 1f7afa7..4ae0215 100644
--- a/dslog/DseventsReader.java
+++ b/dslog/DseventsReader.java
@@ -1,42 +1,78 @@
 package dslog;
 
+import java.io.BufferedInputStream;
 import java.io.Closeable;
 import java.io.IOException;
 import java.io.InputStream;
-import java.lang.UnsupportedOperationException;
 import java.time.Instant;
+import java.util.Iterator;
+import java.util.NoSuchElementException;
 
-class DseventsReader implements Closeable {
-	private final InputStream reader;
+class DseventsReader implements Closeable, Iterator<DseventsReader.Event> {
+	public static class Event {
+		public Instant time;
+		public String message;
+	}
 
-	public final int version;
-	public final Instant startTime;
+	/*============================================================*\
+	|| Primitive IO                                               ||
+	\*============================================================*/
 
+	private final InputStream reader;
 	public DseventsReader(InputStream reader) throws IOException {
+		if (!reader.markSupported()) {
+			reader = new BufferedInputStream(reader);
+		}
 		this.reader = reader;
-		this.version = Read.i32(reader);
-		switch (this.version) {
-		case 0:
-			throw new UnsupportedOperationException("TODO: DSEVENTS v0 support");
-		case 1:
-		case 2:
-		case 3: // 2016-now
-			this.startTime = Read.LVTimestamp(reader);
-			break;
-		default:
-			throw new UnsupportedOperationException("DSEVENTS file version ("+this.version+") newer than log reader (3)");
+	}
+
+	private boolean atEOF() throws IOException {
+		reader.mark(2);
+		boolean eof = (reader.read() < 0);
+		reader.reset();
+		return eof;
+	}
+
+	/*============================================================*\
+	|| Parsing                                                    ||
+	\*============================================================*/
+
+	private int m_version;
+	private boolean m_haveVersion = false;
+	public int version() throws IOException {
+		if (!m_haveVersion) {
+			m_version = Read.i32(reader);
+			m_haveVersion = true;
 		}
+		return m_version;
 	}
 
-	public static class Event {
-		public Instant time;
-		public String message;
+	private Instant m_startTime;
+	public Instant startTime() throws IOException {
+		if (m_startTime == null) {
+			switch (version()) {
+			case 0:
+				throw new UnsupportedVersionException("DSEVENTS (TODO)", 0);
+			case 1:
+			case 2:
+			case 3: // 2016-now
+				m_startTime = Read.LVTimestamp(reader);
+				break;
+			default:
+				throw new UnsupportedVersionException("DSEVENTS", version(), 3);
+			}
+		}
+		return m_startTime;
 	}
 
 	public Event readEvent() throws IOException{
-		switch (version) {
+		startTime();
+		if (atEOF()) {
+			return null;
+		}
+		switch (version()) {
 		case 0:
-			throw new UnsupportedOperationException("TODO: DSEVENTS v0 support");
+			throw new UnsupportedVersionException("DSEVENTS (TODO)", 0);
 		case 1:
 		case 2:
 		case 3:
@@ -45,10 +81,36 @@ class DseventsReader implements Closeable {
 				message = Read.LVString(reader);
 			}};
 		default:
-			throw new UnsupportedOperationException("DSEVENTS file version newer than log reader");
+			throw new UnsupportedVersionException("DSEVENTS", version(), 3);
 		}
 	}
 
+	/*============================================================*\
+	|| Interfaces                                                 ||
+	\*============================================================*/
+
+	private IOException m_err;
+	private Event m_next;
+	public boolean hasNext() {
+		if (m_next == null) {
+			try {
+				m_next = readEvent();
+			} catch (IOException e) {
+				m_err = e;
+			}
+		}
+		return m_next != null;
+	}
+	public Event next() {
+		if (!hasNext()) {
+			throw new NoSuchElementException();
+		}
+		return m_next;
+	}
+	public IOException err() {
+		return m_err;
+	}
+
 	public void close() throws IOException {
 		reader.close();
 	}
diff --git a/dslog/DslogReader.java b/dslog/DslogReader.java
index 73d7dc5..1c0af25 100644
--- a/dslog/DslogReader.java
+++ b/dslog/DslogReader.java
@@ -1,40 +1,16 @@
 package dslog;
 
+import java.io.BufferedInputStream;
 import java.io.Closeable;
 import java.io.IOException;
 import java.io.InputStream;
-import java.lang.UnsupportedOperationException;
 import java.time.Duration;
 import java.time.Instant;
+import java.util.Iterator;
+import java.util.NoSuchElementException;
 import java.util.stream.IntStream;
 
-class DslogReader implements Closeable {
-	private final InputStream reader;
-
-	public final int version;
-	public final Instant startTime;
-	private long i = 0;
-
-	public DslogReader(InputStream reader) throws IOException {
-		this.reader = reader;
-		this.version = Read.i32(reader);
-		switch (this.version) {
-		case 0: // ????-???? 2012
-			this.startTime = Read.LVTimestamp(reader);
-			break;
-		case 1: // ????-???? 2014
-			this.startTime = Read.LVTimestamp(reader);
-			break;
-		case 2: // ????-2015
-			throw new UnsupportedOperationException("TODO: DSLOG v2 support");
-		case 3: // 2016-now
-			this.startTime = Read.LVTimestamp(reader);
-			break;
-		default:
-			throw new UnsupportedOperationException("DSLOG file version ("+this.version+") newer than log reader (3)");
-		}
-	}
-
+class DslogReader implements Closeable, Iterator<DslogReader.Entry> {
 	public static class Entry {
 		public Instant time;
 
@@ -62,14 +38,70 @@ class DslogReader implements Closeable {
 		public short pdpTemperature;
 	}
 
-	/**
-	 * @see https://www.chiefdelphi.com/forums/showthread.php?t=104689
-	 */
-	public Entry readEntry() throws IOException{
-		switch (version) {
+	/*============================================================*\
+	|| Primitive IO                                               ||
+	\*============================================================*/
+
+	private final InputStream reader;
+	public DslogReader(InputStream reader) throws IOException {
+		if (!reader.markSupported()) {
+			reader = new BufferedInputStream(reader);
+		}
+		this.reader = reader;
+	}
+
+	private boolean atEOF() throws IOException {
+		reader.mark(2);
+		boolean eof = (reader.read() < 0);
+		reader.reset();
+		return eof;
+	}
+
+	/*============================================================*\
+	|| Parsing                                                    ||
+	\*============================================================*/
+
+	private int m_version;
+	private boolean m_haveVersion = false;
+	public int version() throws IOException {
+		if (!m_haveVersion) {
+			m_version = Read.i32(reader);
+			m_haveVersion = true;
+		}
+		return m_version;
+	}
+
+	private Instant m_startTime;
+	public Instant startTime() throws IOException {
+		if (m_startTime == null) {
+			switch (version()) {
+			case 0: // ????-???? 2012
+				m_startTime = Read.LVTimestamp(reader);
+				break;
+			case 1: // ????-???? 2014
+				m_startTime = Read.LVTimestamp(reader);
+				break;
+			case 2: // ????-2015
+				throw new UnsupportedVersionException("DSLOG (TODO)", 2);
+			case 3: // 2016-now
+				m_startTime = Read.LVTimestamp(reader);
+				break;
+			default:
+				throw new UnsupportedVersionException("DSLOG", version(), 3);
+			}
+		}
+		return m_startTime;
+	}
+
+	private long i = 0;
+	public Entry readEntry() throws IOException {
+		if (atEOF()) {
+			return null;
+		}
+		switch (version()) {
 		case 0:
 			return new Entry() {{
-				time = startTime.plusMillis(20*i++);
+				time = startTime().plusMillis(20*i++);
 
 				/*  0  = 0 */
 				/*  0+4= 4 */tripTime = Duration.ofNanos((long)(Read.f32(reader)*1000));
@@ -86,9 +118,7 @@ class DslogReader implements Closeable {
 			}};
 		case 1:
 			return new Entry() {{
-				time = startTime.plusMillis(20*i++);
-
-				time = startTime.plusMillis(20*i++);
+				time = startTime().plusMillis(20*i++);
 
 				/*  0  = 0 */
 				/*  0+4= 4 */tripTime = Duration.ofNanos((long)(Read.f32(reader)*1000));
@@ -104,10 +134,10 @@ class DslogReader implements Closeable {
 				/* 13+1=14 */lostPackets = Read.i8(reader);
 			}};
 		case 2:
-			throw new UnsupportedOperationException("TODO: DSLOG v2 support");
+			throw new UnsupportedVersionException("DSLOG (TODO)", 2);
 		case 3:
 			return new Entry() {{
-				time = startTime.plusMillis(20*i++);
+				time = startTime().plusMillis(20*i++);
 				// Read the 35-byte structure
 
 				// Read the 10 bytes of non-PDP data
@@ -147,10 +177,36 @@ class DslogReader implements Closeable {
 				/* 24+1=25 */pdpTemperature = Read.u8(reader);
 			}};
 		default:
-			throw new UnsupportedOperationException("DSLOG file version newer than log reader");
+			throw new UnsupportedVersionException("DSLOG", version(), 3);
 		}
 	}
 
+	/*============================================================*\
+	|| Interfaces                                                 ||
+	\*============================================================*/
+
+	private IOException m_err;
+	private Entry m_next;
+	public boolean hasNext() {
+		if (m_next == null) {
+			try {
+				m_next = readEntry();
+			} catch (IOException e) {
+				m_err = e;
+			}
+		}
+		return m_next != null;
+	}
+	public Entry next() {
+		if (!hasNext()) {
+			throw new NoSuchElementException();
+		}
+		return m_next;
+	}
+	public IOException err() {
+		return m_err;
+	}
+
 	public void close() throws IOException {
 		reader.close();
 	}
diff --git a/dslog/Logdir.java b/dslog/Logdir.java
index 90661bb..b798757 100644
--- a/dslog/Logdir.java
+++ b/dslog/Logdir.java
@@ -42,7 +42,7 @@ class Logdir {
 				if (filename.endsWith(".dslog")) {
 					String setname = filename.substring(0, filename.lastIndexOf('.'));
 					try (DslogReader dslog = new DslogReader(Files.newInputStream(filepath))) {
-						getSet(logsets, setname).dslog = ""+dslog.version;
+						getSet(logsets, setname).dslog = ""+dslog.version();
 					} catch (Exception e) {
 						getSet(logsets, setname).pdplog = "☠";
 						throw e;
@@ -50,7 +50,7 @@ class Logdir {
 				} else if (filename.endsWith(".dsevents")) {
 					String setname = filename.substring(0, filename.lastIndexOf('.'));
 					try (DseventsReader dsevents = new DseventsReader(Files.newInputStream(filepath))) {
-						getSet(logsets, setname).dsevents = ""+dsevents.version;
+						getSet(logsets, setname).dsevents = ""+dsevents.version();
 					} catch (Exception e) {
 						getSet(logsets, setname).pdplog = "☠";
 						throw e;
@@ -58,7 +58,7 @@ class Logdir {
 				} else if (filename.endsWith(".pdplog")) {
 					String setname = filename.substring(0, filename.lastIndexOf('.'));
 					try (PdplogReader pdplog = new PdplogReader(Files.newInputStream(filepath))) {
-						getSet(logsets, setname).pdplog = ""+pdplog.version;
+						getSet(logsets, setname).pdplog = ""+pdplog.version();
 					} catch (Exception e) {
 						getSet(logsets, setname).pdplog = "☠";
 						throw e;
diff --git a/dslog/Main.java b/dslog/Main.java
index 0c95c50..5ea1a64 100644
--- a/dslog/Main.java
+++ b/dslog/Main.java
@@ -14,8 +14,8 @@ class Main {
 		for (String filename : args) {
 			System.out.println("Filename: "+filename);
 			DslogReader file = new DslogReader(Files.newInputStream(Paths.get(filename)));
-			System.out.println("Format Version: "+file.version);
-			System.out.println("Start Time: "+file.startTime);
+			System.out.println("Format Version: "+file.version());
+			System.out.println("Start Time: "+file.startTime());
 			CsvWriter.Dslog2CSV(file, System.out);
 		}
 	}
diff --git a/dslog/PdplogReader.java b/dslog/PdplogReader.java
index 3df9c2b..2618101 100644
--- a/dslog/PdplogReader.java
+++ b/dslog/PdplogReader.java
@@ -1,25 +1,54 @@
 package dslog;
 
+import java.io.BufferedInputStream;
 import java.io.Closeable;
 import java.io.IOException;
 import java.io.InputStream;
-import java.lang.UnsupportedOperationException;
 
 class PdplogReader implements Closeable {
-	private final InputStream reader;
 
-	public final int version;
+	/*============================================================*\
+	|| Primitive IO                                               ||
+	\*============================================================*/
 
+	private final InputStream reader;
 	public PdplogReader(InputStream reader) throws IOException {
+		if (!reader.markSupported()) {
+			reader = new BufferedInputStream(reader);
+		}
 		this.reader = reader;
-		this.version = Read.i32(reader);
-		switch (this.version) {
+	}
+
+	private boolean atEOF() throws IOException {
+		reader.mark(2);
+		boolean eof = (reader.read() < 0);
+		reader.reset();
+		return eof;
+	}
+
+
+	/*============================================================* \
+	|| Parsing                                                    ||
+	\*============================================================*/
+
+	private int m_version;
+	private boolean m_haveVersion = false;
+	public int version() throws IOException {
+		if (!m_haveVersion) {
+			m_version = Read.i32(reader);
+			m_haveVersion = true;
+		}
+		return m_version;
+	}
+
+	public void read() throws IOException {
+		switch (version()) {
 		case 0: // ????-????
-			throw new UnsupportedOperationException("TODO: PDPLOG v0 support");
+			throw new UnsupportedVersionException("PDPLOG (TODO)", 0);
 		case 1: // ????-2015
-			throw new UnsupportedOperationException("TODO: PDPLOG v1 support");
+			throw new UnsupportedVersionException("PDPLOG (TODO)", 1);
 		default:
-			throw new UnsupportedOperationException("Unrecognized PDPLOG version: "+this.version);
+			throw new UnsupportedVersionException("PDPLOG", version(), 1);
 		}
 	}
 
diff --git a/dslog/UnsupportedVersionException.java b/dslog/UnsupportedVersionException.java
new file mode 100644
index 0000000..2667804
--- /dev/null
+++ b/dslog/UnsupportedVersionException.java
@@ -0,0 +1,12 @@
+package dslog;
+
+import java.io.IOException;
+
+class UnsupportedVersionException extends IOException {
+	public UnsupportedVersionException(String thing, int version) {
+		super("Unsupported file format version: "+thing+" v"+version);
+	}
+	public UnsupportedVersionException(String thing, int version, int cur) {
+		super("File format version ("+thing+" v"+version+") new that log reader ("+cur+")");
+	}
+}