diff options
| -rw-r--r-- | src/zip.cr | 20 |
1 files changed, 15 insertions, 5 deletions
@@ -1280,23 +1280,33 @@ module Zip raise Error.new("too small for end of central directory") end + # create buffer and memory io around it + buf = Bytes.new(22) + mem_io = MemoryIO.new(buf, false) + curr_pos = end_pos - 22 while curr_pos >= 0 - # seek to current position + # seek to current position and load possible cdr into buffer io.pos = curr_pos + io.read(buf) + + # rewind memory io + mem_io.rewind # read what might be the end_cdr magic - maybe_end_magic = UInt32.from_io(io, LE) + maybe_end_magic = UInt32.from_io(mem_io, LE) if maybe_end_magic == MAGIC[:cdr_footer] # jump to archive commment len (maybe) - maybe_comment_len_pos = curr_pos + 20 - io.pos = maybe_comment_len_pos + mem_io.pos = 20 # get archive commment len (maybe) - maybe_comment_len = UInt16.from_io(io, LE) + maybe_comment_len = UInt16.from_io(mem_io, LE) if curr_pos + 22 + maybe_comment_len == end_pos + # close memio + mem_io.close + # magic and comment line up: probably found end_cdr return { curr_pos, end_pos } end |