new file mode 100644
--- /dev/null
+++ b/mercurial/mdiff.py
@@ -0,0 +1,76 @@
+#!/usr/bin/python
+import difflib, struct
+from cStringIO import StringIO
+
+def unidiff(a, b, fn):
+ a = a.splitlines(1)
+ b = b.splitlines(1)
+ l = difflib.unified_diff(a, b, fn, fn)
+ return "".join(l)
+
+def textdiff(a, b):
+ return diff(a.splitlines(1), b.splitlines(1))
+
+def sortdiff(a, b):
+ la = lb = 0
+
+ while 1:
+ if la >= len(a) or lb >= len(b): break
+ if b[lb] < a[la]:
+ si = lb
+ while lb < len(b) and b[lb] < a[la] : lb += 1
+ yield "insert", la, la, si, lb
+ elif a[la] < b[lb]:
+ si = la
+ while la < len(a) and a[la] < b[lb]: la += 1
+ yield "delete", si, la, lb, lb
+ else:
+ la += 1
+ lb += 1
+
+ si = lb
+ while lb < len(b):
+ lb += 1
+ yield "insert", la, la, si, lb
+
+ si = la
+ while la < len(a):
+ la += 1
+ yield "delete", si, la, lb, lb
+
+def diff(a, b, sorted=0):
+ bin = []
+ p = [0]
+ for i in a: p.append(p[-1] + len(i))
+
+ if sorted:
+ d = sortdiff(a, b)
+ else:
+ d = difflib.SequenceMatcher(None, a, b).get_opcodes()
+
+ for o, m, n, s, t in d:
+ if o == 'equal': continue
+ s = "".join(b[s:t])
+ bin.append(struct.pack(">lll", p[m], p[n], len(s)) + s)
+
+ return "".join(bin)
+
+def patch(a, bin):
+ last = pos = 0
+ r = []
+
+ while pos < len(bin):
+ p1, p2, l = struct.unpack(">lll", bin[pos:pos + 12])
+ pos += 12
+ r.append(a[last:p1])
+ r.append(bin[pos:pos + l])
+ pos += l
+ last = p2
+ r.append(a[last:])
+
+ return "".join(r)
+
+
+
+
+