Android 稀疏镜像格式 (android sparse image format)

(原文)http://2net.co.uk/tutorial/android-sparse-image-formatsimg_dump.py. Here is an example:

$ system/core/libsparse/simg_dump.py -v dist_output/target_files-eng/IMAGES/userdata.img 
dist_output/target_files-eng/IMAGES/userdata.img: Total of 524288 4096-byte output blocks in 55 input chunks.
            input_bytes      output_blocks
chunk    offset     number  offset  number
   1         40       4096       0       1 Raw data           
   2       4148       4096       1       1 Raw data           
   3       8256     520192       2     127 Raw data           
   4     528460       8192     129       2 Raw data           
   5     536664    2097152     131     512 Raw data           
   6    2633828   33554432     643    8192 Raw data           
   7   36188272       4096    8835       1 Raw data           
   8   36192380       4096    8836       1 Raw data           
   9   36196488       4096    8837       1 Raw data           
  10   36200596          0    8838   23930 Don't care         
  11   36200608       4096   32768       1 Raw data           
  12   36204716       4096   32769       1 Raw data           
  13   36208824          0   32770     127 Don't care         
  14   36208836       8192   32897       2 Raw data           
  15   36217040          0   32899   32637 Don't care         
  16   36217052       8192   65536       2 Raw data           
  17   36225256          0   65538   32766 Don't care         
  18   36225268       4096   98304       1 Raw data           
  19   36229376       4096   98305       1 Raw data           
  20   36233484          0   98306     127 Don't care         
  21   36233496       8192   98433       2 Raw data           
  22   36241700          0   98435   32637 Don't care         
  23   36241712       8192  131072       2 Raw data           
  24   36249916          0  131074   32766 Don't care         
  25   36249928       4096  163840       1 Raw data           
  26   36254036       4096  163841       1 Raw data           
  27   36258144          0  163842     127 Don't care         
  28   36258156       8192  163969       2 Raw data           
  29   36266360          0  163971   32637 Don't care         
  30   36266372       8192  196608       2 Raw data           
  31   36274576          0  196610   32766 Don't care         
  32   36274588       4096  229376       1 Raw data           
  33   36278696       4096  229377       1 Raw data           
  34   36282804          0  229378     127 Don't care         
  35   36282816       8192  229505       2 Raw data           
  36   36291020          0  229507   32637 Don't care         
  37   36291032       8192  262144       2 Raw data           
  38   36299236          0  262146   32766 Don't care         
  39   36299248       4096  294912       1 Raw data           
  40   36303356       4096  294913       1 Raw data           
  41   36307464          0  294914     127 Don't care         
  42   36307476       8192  295041       2 Raw data           
  43   36315680          0  295043   32637 Don't care         
  44   36315692       8192  327680       2 Raw data           
  45   36323896          0  327682   32766 Don't care         
  46   36323908       8192  360448       2 Raw data           
  47   36332112          0  360450   32766 Don't care         
  48   36332124       8192  393216       2 Raw data           
  49   36340328          0  393218   32766 Don't care         
  50   36340340       8192  425984       2 Raw data           
  51   36348544          0  425986   32766 Don't care         
  52   36348556       8192  458752       2 Raw data           
  53   36356760          0  458754   32766 Don't care         
  54   36356772       8192  491520       2 Raw data           
  55   36364976          0  491522   32766 Don't care         
       36364976             524288         End