fix: Fixed MP3 header search to not false match on BOMs

src/eyed3/mp3/__init__.py

@@ -1,20 +1,3 @@
-################################################################################
-#  Copyright (C) 2002-2007  Travis Shirk <travis@pobox.com>
-#
-#  This program is free software; you can redistribute it and/or modify
-#  it under the terms of the GNU General Public License as published by
-#  the Free Software Foundation; either version 2 of the License, or
-#  (at your option) any later version.
-#
-#  This program is distributed in the hope that it will be useful,
-#  but WITHOUT ANY WARRANTY; without even the implied warranty of
-#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-#  GNU General Public License for more details.
-#
-#  You should have received a copy of the GNU General Public License
-#  along with this program; if not, see <http://www.gnu.org/licenses/>.
-#
-################################################################################
 import os
 import re
 
@@ -71,6 +54,7 @@ def __init__(self, file_obj, start_offset, tag):
         self.bit_rate = (None, None)
         '''2-tuple, (vrb?:boolean, bitrate:int)'''
 
+        header_pos = 0
         while self.mp3_header is None:
             # Find first mp3 header
             (header_pos,
@@ -116,7 +100,6 @@ def __init__(self, file_obj, start_offset, tag):
         self.size_bytes = os.stat(file_obj.name)[stat.ST_SIZE]
 
         # Compute track play time.
-        tpf = None
         if self.xing_header and self.xing_header.vbr:
             tpf = timePerFrame(self.mp3_header, True)
             self.time_secs = tpf * self.xing_header.numFrames

src/eyed3/mp3/headers.py

@@ -73,19 +73,35 @@ def findHeader(fp, start_pos=0):
     bytes. If no header is found header_int will equal 0.
     """
 
+    def isBOM(buffer, pos):
+        try:
+            return 254 in (buffer[pos + 1], buffer[pos - 1])
+        except IndexError:
+            return False
+
     def find_sync(fp, start_pos=0):
         CHUNK_SIZE = 8192  # Measured as optimal
 
         fp.seek(start_pos)
         data = fp.read(CHUNK_SIZE)
 
         while data:
-            sync_pos = data.find(b'\xff', 0)
-            if sync_pos >= 0:
-                header = data[sync_pos:sync_pos + 4]
-                if len(header) == 4:
-                    return (start_pos + sync_pos, header)
+            pos = 0
+            while pos >= 0 and pos < CHUNK_SIZE:
+                pos = data.find(b"\xff", pos)
+                if pos == -1:
+                    break
+
+                if not isBOM(data, pos):
+                    header = data[pos:pos + 4]
+                    if len(header) == 4:
+                        return (start_pos + pos, header)
+
+                pos += 1
+
+            start_pos += len(data)
             data = fp.read(CHUNK_SIZE)
+
         return (None, None)
 
     sync_pos, header_bytes = find_sync(fp, start_pos)
@@ -103,7 +119,6 @@ def timePerFrame(mp3_header, vbr):
     rate from ``mp3_header`` are used to compute the number of seconds
     (fractional float point value) per mp3 frame. Be sure to set ``vbr`` True
     when dealing with VBR, otherwise playtimes may be incorrect."""
-
     # https://bitbucket.org/nicfit/eyed3/issue/32/mp3audioinfotime_secs-incorrect-for-mpeg2
     if mp3_header.version >= 2.0 and vbr:
         row = _mp3VersionKey(mp3_header.version)

src/test/mp3/test_mp3.py

@@ -1,28 +1,11 @@
-# -*- coding: utf-8 -*-
-################################################################################
-#  Copyright (C) 2009  Travis Shirk <travis@pobox.com>
-#
-#  This program is free software; you can redistribute it and/or modify
-#  it under the terms of the GNU General Public License as published by
-#  the Free Software Foundation; either version 2 of the License, or
-#  (at your option) any later version.
-#
-#  This program is distributed in the hope that it will be useful,
-#  but WITHOUT ANY WARRANTY; without even the implied warranty of
-#  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-#  GNU General Public License for more details.
-#
-#  You should have received a copy of the GNU General Public License
-#  along with this program; if not, see <http://www.gnu.org/licenses/>.
-#
-################################################################################
 import unittest
 import os
 from io import BytesIO
 from .. import DATA_D
 
 import eyed3
 
+
 def testvalidHeader():
     from eyed3.mp3.headers import isValidHeader
 
@@ -59,6 +42,7 @@ def testvalidHeader():
     assert isValidHeader(0xfffb7050)
     assert isValidHeader(0xfffb32c0)
 
+
 def testFindHeader():
     from eyed3.mp3.headers import findHeader
 
@@ -86,7 +70,6 @@ def testFindHeader():
     assert header_int == 0xfffb9064
 
 
-
 @unittest.skipIf(not os.path.exists(DATA_D), "test requires data files")
 def testBasicVbrMp3():
     audio_file = eyed3.load(os.path.join(DATA_D, "notag-vbr.mp3"))