Add an error position iterator class

src/obitools/word/_binary.pyx

@@ -4,6 +4,9 @@ Created on 2 juil. 2009
 @author: coissac
 '''
 
+
+maxword = sizeof(unsigned long int) * 8 /2
+
 cdef import from "math.h":
     double ceil(double x)
     double log(double x)
@@ -216,4 +219,51 @@ cpdef bint matchPattern(unsigned long int word,pattern):
     match|= eq & (eq >> 1) &  pattern.t        
     return match == all
 
+cdef class ErrorPositionIterator:
+        
+    cdef int _wsize
+    cdef int _errors
+    cdef unsigned long int _mask
+    cdef int _errorpos[32]
+    cdef bint _end
+    
+    def __init__(self,wordsize,errorcount):
+        self._wsize=wordsize
+        self._errors=errorcount
+        self._mask=0
+        for i in range(errorcount):
+            self._errorpos[i]=i
+        self._end=False
+            
+    def __iter__(self):
+        return self
+    
+    def next(self):
+        cdef unsigned long int rep
+        cdef bint move=False
+        cdef int i
+        if self._end:
+            raise StopIteration
+        
+        rep = 0
+        for i in range(self._errors):
+            rep |= 1 << self._errorpos[i]
+            print bin2str(rep)
+            
+        move=False
+        i=0
+        while (not move):
+            if self._errorpos[i]<self._errorpos[i+1]-1:
+                 self._errorpos[i]+=1
+                 move=True
+                 i=0
+                 print "pos %d/%d moved" % (i,self._wsize)
+            else:
+                self._errorpos[i]=i
+                i+=1
+            if i==self._errors-1 and self._errorpos[i]==self._wsize:
+                self._end=True
+                move=True
+                
+        return rep