1  
   2  REBOL []
   3  
   4  
   5  do-by-type: func [
   6      value
   7      actions [block!]
   8      /default
   9          def-action [block!]
  10      /local action
  11  ][
  12      either action: select actions type?/word value [
  13          ;print mold action
  14          do bind/copy action 'value
  15      ][
  16          if default [do bind/copy def-action 'value]
  17      ]
  18  ]
  19  
  20  to-binary-ex: func [value] [
  21      do-by-type value [
  22          binary! [value]
  23          string! [to-binary value]
  24          file!   [read/binary value]
  25      ]
  26  ]
  27  
  28  xor-diff: func [
  29      a [binary! string! file!]
  30      b [binary! string! file!]
  31      /local bin-a bin-b
  32  ][
  33      bin-a: to-binary-ex a
  34      bin-b: to-binary-ex b
  35      bin-a xor bin-b
  36  ]
  37  
  38  make-patch: func [
  39      a [binary! string! file!]
  40      b [binary! string! file!]
  41  ][
  42      compress xor-diff a b
  43  ]
  44  
  45  apply-patch: func [
  46      data  [binary! string! file!]
  47      patch [binary! string!]
  48      /local result
  49  ][
  50      result: xor-diff data decompress patch
  51      ; If they gave us a string as the source, return a string.
  52      ;?? If they give us a file, should we write back out to it?
  53      either string? data [to-string result][result]
  54  ]
  55  
  56  
  57  a: "Now is the time for all good men to come to the aid of their country..."
  58  b: {Now is the time for all good men to come to the aid of their country...
  59  whether 'tis nolber to suffer the slings and arrows...}
  60  ;d1: xor-diff a b
  61  p1: make-patch a b
  62  bp: apply-patch a p1
  63  
  64  
  65  
  66  change-dir %./test-files
  67  
  68  files: sort read %.
  69  print mold files
  70  print [files/1 files/2]
  71  fp-1-2: make-patch files/1 files/2
  72  fp-2-3: make-patch files/2 files/3
  73  fp-3-4: make-patch files/3 files/4
  74  fp-a-b: make-patch files/5 files/6
  75  
  76  pp-a-b: apply-patch files/5 fp-a-b
  77  
  78  change-dir %..
  79  
  80  
  81  halt
  82  
  83