1 files changed, 101 insertions, 0 deletions
diff --git a/src/compression/rle.c b/src/compression/rle.c
new file mode 100644
index 0000000..6486137
--- /dev/null
+++ b/src/compression/rle.c
@@ -0,0 +1,101 @@
+/* This code is part of the tng compression routines.
+ *
+ * Written by Daniel Spangberg
+ * Copyright (c) 2010, 2013, The GROMACS development team.
+ *
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public License
+ * as published by the Free Software Foundation; either version 2.1
+ * of the License, or (at your option) any later version.
+ */
+
+
+#include "rle.h"
+
+static void add_rle(unsigned int *rle,
+		    int v,int nsim,
+		    int *j,int min_rle)
+{
+  if (nsim>min_rle)
+    {
+      /* Insert run-length */
+      unsigned int run=((unsigned int)nsim);
+      while (run>1)
+	{
+	  if (run&0x1U)
+	    rle[(*j)++]=1;
+	  else
+	    rle[(*j)++]=0;
+	  run>>=1;
+	}
+      nsim=1;
+    }
+  while (nsim--)
+    rle[(*j)++]=v+2;
+}
+
+/* Run length encoding.
+   Acceptable inputs are about 16 bits (0-0xFFFF)
+   If input is 0-N output will be be values of 0-(N+2) */
+void Ptngc_comp_conv_to_rle(unsigned int *vals, int nvals,
+		      unsigned int *rle, int *nrle,
+		      int min_rle)
+{
+  int i;
+  int j=0;
+  int nsim=0;
+  int v=-1;
+  for (i=0; i<nvals; i++)
+    {
+      if (!nsim)
+	{
+	  v=vals[i];
+	  nsim=1;
+	}
+      else
+	{
+	  if (v==vals[i])
+	    nsim++;
+	  else
+	    {
+	      add_rle(rle,v,nsim,&j,min_rle);
+	      nsim=1;
+	      v=vals[i];
+	    }
+	}
+    }
+  if (nsim!=0)
+    add_rle(rle,v,nsim,&j,min_rle);
+  *nrle=j;
+}
+
+void Ptngc_comp_conv_from_rle(unsigned int *rle,
+			unsigned int *vals, int nvals)
+{
+  int i=0;
+  int j=0;
+  while (i<nvals)
+    {
+      int k;
+      unsigned int len=0;
+      unsigned int mask=0x1;
+      unsigned int v=rle[j++];
+      unsigned int hasrle=0;
+      while (v<2)
+	{
+	  if (v)
+	    len|=mask;
+	  mask<<=1;
+	  hasrle=1;
+	  v=rle[j++];
+	}
+      if (!hasrle)
+	len=1;
+      else
+	len|=mask;
+      for (k=0; k<(int)len; k++)
+	vals[i++]=v-2;
+    }
+}
+