typedef struct __attribute__((packed)) {
    magic32_t magic;            /* 0x02B50C13 */
    uint8_t compress_algorithm; /* compress method algorithm number */
    uint8_t compress_hint;      /* compress method hint */
    uint32_t uncompress_size;   /* size of the block before compressed */
    uint32_t compress_size;     /* size of the block after compressed */
    uint32_t crc32;             /* CRC value of the block */
} block_header;
typedef struct __attribute__((packed)) {
    magic32_t magic;             
    uint8_t compress_algorithm;  
    uint8_t compress_hint;       
    uint32_t uncompress_size;    
    uint32_t compress_size;      
    uint32_t crc32;              
} block_header;