X-Git-Url: http://git.nguyen.vg/gitweb/?a=blobdiff_plain;f=src%2Ftree.ml;fp=src%2Ftree.ml;h=9b3d4bc52bdcecdc0685053ccbad4ef8268cdfea;hb=ecec752325cb3d207894a4f8d772936bd7ad9f4a;hp=9c6eff3adb19a51e9afcdbd0cb9f21a702da79b3;hpb=db0ad408721f202e33785958211fe6e4228fce8f;p=SXSI%2Fxpathcomp.git

diff --git a/src/tree.ml b/src/tree.ml
index 9c6eff3..9b3d4bc 100644
--- a/src/tree.ml
+++ b/src/tree.ml
@@ -170,10 +170,22 @@ end
 type bit_vector = string
 
 external bool_of_int : int -> bool = "%identity"
+external int_of_bool : bool -> int = "%identity"
 
 let bit_vector_unsafe_get v i =
   bool_of_int
     (((Char.code (String.unsafe_get v (i lsr 3))) lsr (i land 7)) land 1)
+let chr (c:int) : char = Obj.magic (c land 0xff)
+let bit_vector_unsafe_set v i b =
+  let j = i lsr 3 in
+  let c = Char.code v.[j] in
+  let bit = int_of_bool b in
+  let mask = bit lsl (i land 7) in
+  if b then v.[j] <- chr (c lor mask) else v.[j] <- (chr (c land (lnot mask)))
+
+let bit_vector_create n =
+  let len = if n <= 0 then 0 else (n - 1) / 8 + 1 in
+  String.make len '\000' 
 
 type t = {
   doc : tree;