equity/compiler/optimize.go

   1 package compiler
   2
   3 import "strings"
   4
   5 var optimizations = []struct {
   6         before, after string
   7 }{
   8         {"0 ROLL", ""},
   9         {"0 PICK", "DUP"},
  10         {"1 ROLL", "SWAP"},
  11         {"1 PICK", "OVER"},
  12         {"2 ROLL", "ROT"},
  13         {"TRUE VERIFY", ""},
  14         {"SWAP SWAP", ""},
  15         {"OVER OVER", "2DUP"},
  16         {"SWAP OVER", "TUCK"},
  17         {"DROP DROP", "2DROP"},
  18         {"SWAP DROP", "NIP"},
  19         {"5 ROLL 5 ROLL", "2ROT"},
  20         {"3 PICK 3 PICK", "2OVER"},
  21         {"3 ROLL 3 ROLL", "2SWAP"},
  22         {"2 PICK 2 PICK 2 PICK", "3DUP"},
  23         {"1 ADD", "1ADD"},
  24         {"1 SUB", "1SUB"},
  25         {"EQUAL VERIFY", "EQUALVERIFY"},
  26         {"SWAP TXSIGHASH ROT", "TXSIGHASH SWAP"},
  27         {"SWAP EQUAL", "EQUAL"},
  28         {"SWAP EQUALVERIFY", "EQUALVERIFY"},
  29         {"SWAP ADD", "ADD"},
  30         {"SWAP BOOLAND", "BOOLAND"},
  31         {"SWAP BOOLOR", "BOOLOR"},
  32         {"SWAP MIN", "MIN"},
  33         {"SWAP MAX", "MAX"},
  34         {"DUP 2 PICK EQUAL", "2DUP EQUAL"},
  35         {"DUP 2 PICK EQUALVERIFY", "2DUP EQUALVERIFY"},
  36         {"DUP 2 PICK ADD", "2DUP ADD"},
  37         {"DUP 2 PICK BOOLAND", "2DUP BOOLAND"},
  38         {"DUP 2 PICK BOOLOR", "2DUP BOOLOR"},
  39         {"DUP 2 PICK MIN", "2DUP MIN"},
  40         {"DUP 2 PICK MAX", "2DUP MAX"},
  41 }
  42
  43 func optimize(opcodes string) string {
  44         opcodes = " " + opcodes + " "
  45         looping := true
  46         for looping {
  47                 looping = false
  48                 for _, o := range optimizations {
  49                         before := " " + o.before + " "
  50                         var after string
  51                         if o.after == "" {
  52                                 after = " "
  53                         } else {
  54                                 after = " " + o.after + " "
  55                         }
  56                         newOpcodes := strings.Replace(opcodes, before, after, -1)
  57                         if newOpcodes != opcodes {
  58                                 looping = true
  59                                 opcodes = newOpcodes
  60                         }
  61                 }
  62         }
  63         return strings.TrimSpace(opcodes)
  64 }