optimize lookup speed (ls0f#31)

phone/phone.py

@@ -8,11 +8,11 @@
 
 if sys.version_info > (3, 0):
     def get_record_content(buf, start_offset):
-        end_offset = start_offset + buf[start_offset:-1].find(b'\x00')
+        end_offset = buf.find(b'\x00', start_offset)
         return buf[start_offset:end_offset].decode()
 else:
     def get_record_content(buf, start_offset):
-        end_offset = start_offset + buf[start_offset:-1].find('\x00')
+        end_offset = buf.find('\x00', start_offset)
         return buf[start_offset:end_offset]
 
 
@@ -32,7 +32,7 @@ def __init__(self, dat_file=None):
         self.version, self.first_phone_record_offset = struct.unpack(
             self.head_fmt, self.buf[:self.head_fmt_length])
         self.phone_record_count = (len(
-            self.buf) - self.first_phone_record_offset) / self.phone_fmt_length
+            self.buf) - self.first_phone_record_offset) // self.phone_fmt_length
 
     def get_phone_dat_msg(self):
         print("版本号:{}".format(self.version))
@@ -74,10 +74,12 @@ def _lookup_phone(self, phone_num):
 
         left = 0
         right = self.phone_record_count
+        buflen = len(self.buf)
         while left <= right:
-            middle = int((left + right) / 2)
-            current_offset = int(self.first_phone_record_offset + middle * self.phone_fmt_length)
-            if current_offset >= len(self.buf):
+            middle = (left + right) // 2
+            current_offset = (self.first_phone_record_offset +
+                middle * self.phone_fmt_length)
+            if current_offset >= buflen:
                 return
 
             buffer = self.buf[current_offset: current_offset + self.phone_fmt_length]