--- a/HP3562A/__init__.py	Mon Dec 17 18:59:45 2007 +0100
+++ b/HP3562A/__init__.py	Tue Dec 18 00:23:10 2007 +0100
@@ -12,8 +12,90 @@
 ---------
 
 """
+import struct
+import gpib
 
-from gpib import gpib
+########################################
+# HP3562A internal binary types decoders
+
+def decode_float(s):
+    assert len(s) in [4,8]
+    # exponential term 
+    e = ord(s[-1])
+    if e & 0x80:
+        e = e - 256
+
+    # mantissa
+    m = [ord(x) for x in s[:-1]]
+    M = 0.
+    for i in range(len(s)-1):
+        #M += m[i]<<(i*8)
+        M += float(m[i])/2**((i+1)*8)
+    # XXX how do we deal negative numbers?
+    #if m[0] & 0x80:
+    #    M = M - 2^(len(s))
+    return M * 2**(e+1)
+
+def decode_string(s):
+    nb = ord(s[0])
+    s = s[1:nb+2]
+    r = ""
+    # XXX why do we need to do this? It's not described in the manual...
+    for c in s:
+        r += chr(ord(c) & 0x7F)
+    return r
+
+
+###
+# Some useful functions
+def format_header(header, head_struct, columns=80):
+    """
+    Pretty print a data block (trace, state or coord) 
+    """
+    todisp = []
+    for row in head_struct:
+        key = row[0]        
+        val = header.get(key, "N/A")
+        if isinstance(val, basestring):
+            val = repr(val)
+        else:
+            val = str(val)
+        todisp.append((key+":", val))
+    maxk = max([len(k) for k, v in todisp])
+    maxv = max([len(v) for k, v in todisp])
+    fmt = "%%-%ds %%-%ds"%(maxk, maxv)
+    w = maxk+maxv+4
+    ncols = columns/w
+    nrows = len(todisp)/ncols
+    res = ""
+    for i in range(nrows):
+        res += "| ".join([fmt%todisp[j*nrows+i] for j in range(ncols)]) + "\n"
+    return res
+
+def decode_header(data, header_struct):    
+    d = data
+    typ = d[:2]
+    assert typ == "#A"
+
+    totlen = struct.unpack('>h', d[2:4])[0]
+    idx = 4
+    tt=0
+    header = {}
+    for i, (nam, dtype, fmt, nbytes) in enumerate(header_struct):
+        if dtype == str:
+            val = decode_string(d[idx:])
+        else:
+            if fmt:
+                v = struct.unpack('>'+fmt, d[idx: idx+nbytes])[0]
+                if isinstance(dtype, dict):
+                    val = dtype.get(int(v), "N/A")
+                else:
+                    val = dtype(v)
+            else:
+                val = dtype(d[idx: idx+nbytes])
+        header[nam] = val
+        idx += nbytes
+    return header, idx
 
 #####################
 # HP3562A constants
@@ -102,3 +184,5 @@
                   (0x40, "ACDA", "Accept date"),
                   #...
                   ]
+
+