add an internal implementation of bin function (bin2str) that is appeared

only in python 2.6

src/obitools/word/_binary.pyx

@@ -4,6 +4,26 @@ Created on 2 juil. 2009
 @author: coissac
 '''
 
+cdef import from "math.h":
+    double ceil(double x)
+    double log(double x)
+
+cdef int binarywordsize(unsigned long long int x):
+    return <int>ceil(log(x)/log(2))
+
+cpdef str bin2str(unsigned long long int x):
+    cdef str rep=''
+    cdef unsigned long long int i
+    cdef int ws = binarywordsize(x)
+    
+    for i in range(ws):
+        if x & (1 << i):
+            rep = '1' + rep
+        else:
+            rep = '0' + rep
+    return rep
+    
+
 
 cdef class WordPattern :
     cdef public unsigned long long int a 
@@ -22,10 +42,10 @@ cdef class WordPattern :
         self.t=t 
         
     def __str__(self):
-        return b"(a:%s,c:%s,g:%s,t:%s)" % (bin(self.a),
-                                           bin(self.c),
-                                           bin(self.g),
-                                           bin(self.t))
+        return b"(a:%s,c:%s,g:%s,t:%s)" % (bin2str(self.a),
+                                           bin2str(self.c),
+                                           bin2str(self.g),
+                                           bin2str(self.t))
         
 cdef unsigned int bitCount(unsigned long long int x):
     cdef unsigned int i=0