1 files changed, 83 insertions, 0 deletions
diff --git a/gr-digital/examples/run_length.py b/gr-digital/examples/run_length.py
new file mode 100755
index 000000000..5020655db
--- /dev/null
+++ b/gr-digital/examples/run_length.py
@@ -0,0 +1,83 @@
+#!/usr/bin/env python
+#
+# Copyright 2007 Free Software Foundation, Inc.
+# 
+# This file is part of GNU Radio
+# 
+# GNU Radio is free software; you can redistribute it and/or modify
+# it under the terms of the GNU General Public License as published by
+# the Free Software Foundation; either version 3, or (at your option)
+# any later version.
+# 
+# GNU Radio is distributed in the hope that it will be useful,
+# but WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
+# GNU General Public License for more details.
+# 
+# You should have received a copy of the GNU General Public License
+# along with GNU Radio; see the file COPYING.  If not, write to
+# the Free Software Foundation, Inc., 51 Franklin Street,
+# Boston, MA 02110-1301, USA.
+# 
+
+from optparse import OptionParser
+import sys
+
+def main():
+    parser = OptionParser()
+    parser.add_option("-f", "--file", default=None,
+                      help="Choose file to read data from.")
+    (options, args) = parser.parse_args()
+
+    if options.file == None:
+        print "Must specify file to read from using '-f'."
+        sys.exit(1)
+    print "Using", options.file, "for data."
+
+    f = open(options.file, 'r')
+    runs = []
+    count = 0
+    current = 0
+    bytes = 0
+    bits = 0
+    
+    for ch in f.read():
+        x = ord(ch)
+        bytes = bytes + 1
+        for i in range(7,-1,-1):
+            bits = bits + 1
+            t = (x >> i) & 0x1
+            if t == current:
+                count = count + 1
+            else:
+                if count > 0:
+                    if len(runs) < count:
+                        for j in range(count - len(runs)):
+                            runs.append(0);
+                    runs[count-1] = runs[count-1] + 1
+
+                current = 1-current;
+                count = 1
+
+    # Deal with last run at EOF
+    if len(runs) < count and count > 0:
+        for j in range(count - len(runs)):
+            runs.append(0);
+    runs[count-1] = runs[count-1] + 1
+
+    chk = 0
+    print "Bytes read: ", bytes
+    print "Bits read:  ", bits
+    print
+    for i in range(len(runs)):
+        chk = chk + runs[i]*(i+1)
+        print "Runs of length", i+1, ":", runs[i]
+    print
+    print "Sum of runs:", chk, "bits"
+    print
+    print "Maximum run length is", len(runs), "bits"
+
+if __name__ == "__main__":
+    main()
+
+