fileform.py 文件源码

def _extract_header(nsis_file, firstheader):
    inflated_data, data_size = inflate_header(nsis_file, firstheader.data_offset)
    header = Header._make(_header_pack.unpack_from(inflated_data))
    firstheader.header = header
    firstheader._raw_header = bytes(inflated_data)
    firstheader._raw_header_c_size = data_size

    # Parse the block headers.
    block_headers = []
    for i in range(BLOCKS_COUNT):
        header_offset = i * _blockheader_pack.size
        block_header = BlockHeader._make(_blockheader_pack.unpack_from(
            header.raw_blocks[header_offset:]))
        block_headers.append(block_header)
    header.blocks = block_headers

    # Parse the install types.
    header.install_types = [
            struct.unpack_from('<I', header.raw_install_types[i:])[0]
                for i in range(0, len(header.raw_install_types), 4)]

    return header