From c6410257eb2894ee086fda5bb5ce88e33a44011a Mon Sep 17 00:00:00 2001
From: Dave Collins <davec@conformal.com>
Date: Wed, 13 Mar 2019 01:12:53 -0500
Subject: [PATCH] txscript: Make alwaysIllegal accept raw opcode.
This converts the alwaysIllegal function defined on a parsed opcode to a
standalone function named isOpcodeAlwaysIllegal which accepts an opcode
as a byte instead in order to make it more flexible for raw script
analysis.
It also updates all callers accordingly.
---
txscript/engine.go | 16 +++++++++++++++-
txscript/opcode.go | 14 --------------
2 files changed, 15 insertions(+), 15 deletions(-)
diff --git a/txscript/engine.go b/txscript/engine.go
index 00973a03..1c6a124b 100644
--- a/txscript/engine.go
+++ b/txscript/engine.go
@@ -194,6 +194,20 @@ func isOpcodeDisabled(opcode byte) bool {
}
}
+// isOpcodeAlwaysIllegal returns whether or not the opcode is always illegal
+// when passed over by the program counter even if in a non-executed branch (it
+// isn't a coincidence that they are conditionals).
+func isOpcodeAlwaysIllegal(opcode byte) bool {
+ switch opcode {
+ case OP_VERIF:
+ return true
+ case OP_VERNOTIF:
+ return true
+ default:
+ return false
+ }
+}
+
// executeOpcode peforms execution on the passed opcode. It takes into account
// whether or not it is hidden by conditionals, but some rules still must be
// tested in this case.
@@ -206,7 +220,7 @@ func (vm *Engine) executeOpcode(pop *parsedOpcode) error {
}
// Always-illegal opcodes are fail on program counter.
- if pop.alwaysIllegal() {
+ if isOpcodeAlwaysIllegal(pop.opcode.value) {
str := fmt.Sprintf("attempt to execute reserved opcode %s",
pop.opcode.name)
return scriptError(ErrReservedOpcode, str)
diff --git a/txscript/opcode.go b/txscript/opcode.go
index 62c6649d..dc4ec50e 100644
--- a/txscript/opcode.go
+++ b/txscript/opcode.go
@@ -692,20 +692,6 @@ func (pop *parsedOpcode) checkParseableInScript(script []byte, scriptPos int) (i
return scriptPos, nil
}
-// alwaysIllegal returns whether or not the opcode is always illegal when passed
-// over by the program counter even if in a non-executed branch (it isn't a
-// coincidence that they are conditionals).
-func (pop *parsedOpcode) alwaysIllegal() bool {
- switch pop.opcode.value {
- case OP_VERIF:
- return true
- case OP_VERNOTIF:
- return true
- default:
- return false
- }
-}
-
// isConditional returns whether or not the opcode is a conditional opcode which
// changes the conditional execution stack when executed.
func (pop *parsedOpcode) isConditional() bool {