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Refactored filetype box to use struct.unpack_from. #130

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John Evans 2014-03-02 07:58:48 -05:00
commit c01079d677
1 changed files with 8 additions and 10 deletions
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18
glymur/jp2box.py
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@ -994,7 +994,7 @@ class DataReferenceBox(Jp2kBox):
@staticmethod
def parse(fptr, offset, length):
"""Parse Label box.
"""Parse data reference box.
Parameters
----------
@ -1124,19 +1124,17 @@ class FileTypeBox(Jp2kBox):
-------
FileTypeBox instance
"""
# Read the brand, minor version.
read_buffer = fptr.read(8)
(brand, minor_version) = struct.unpack('>4sI', read_buffer)
read_buffer = fptr.read(length - 8)
# Extract the brand, minor version.
(brand, minor_version) = struct.unpack_from('>4sI', read_buffer, 0)
if sys.hexversion >= 0x030000:
brand = brand.decode('utf-8')
# Read the compatibility list. Each entry has 4 bytes.
current_pos = fptr.tell()
num_bytes = (offset + length - current_pos) / 4
read_buffer = fptr.read(int(num_bytes) * 4)
# Extract the compatibility list. Each entry has 4 bytes.
num_entries = int((length - 16)/ 4)
compatibility_list = []
for j in range(int(num_bytes)):
entry, = struct.unpack('>4s', read_buffer[4*j:4*(j+1)])
for j in range(int(num_entries)):
entry, = struct.unpack_from('>4s', read_buffer, 8 + j * 4)
if sys.hexversion >= 0x03000000:
entry = entry.decode('utf-8')
compatibility_list.append(entry)