mirror of
https://github.com/nspcc-dev/neo-go.git
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8d4dd2d2e1
This allows easier reuse of opcodes and in some cases allows to eliminate dependencies on the whole vm package, like in compiler that only needs opcodes and doesn't care about VM for any other purpose. And yes, they're opcodes because an instruction is a whole thing with operands, that's what context.Next() returns.
102 lines
2.3 KiB
Go
102 lines
2.3 KiB
Go
package vm
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import (
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"encoding/binary"
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"github.com/CityOfZion/neo-go/pkg/vm/opcode"
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)
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func getNumOfThingsFromInstr(instr opcode.Opcode, param []byte) (int, bool) {
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var nthings int
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switch instr {
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case opcode.PUSH1, opcode.PUSH2, opcode.PUSH3, opcode.PUSH4,
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opcode.PUSH5, opcode.PUSH6, opcode.PUSH7, opcode.PUSH8,
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opcode.PUSH9, opcode.PUSH10, opcode.PUSH11, opcode.PUSH12,
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opcode.PUSH13, opcode.PUSH14, opcode.PUSH15, opcode.PUSH16:
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nthings = int(instr-opcode.PUSH1) + 1
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case opcode.PUSHBYTES1:
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nthings = int(param[0])
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case opcode.PUSHBYTES2:
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nthings = int(binary.LittleEndian.Uint16(param))
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default:
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return 0, false
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}
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if nthings < 1 || nthings > MaxArraySize {
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return 0, false
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}
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return nthings, true
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}
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// IsMultiSigContract checks whether the passed script is a multi-signature
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// contract.
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func IsMultiSigContract(script []byte) bool {
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var nsigs, nkeys int
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ctx := NewContext(script)
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instr, param, err := ctx.Next()
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if err != nil {
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return false
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}
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nsigs, ok := getNumOfThingsFromInstr(instr, param)
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if !ok {
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return false
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}
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for {
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instr, param, err = ctx.Next()
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if err != nil {
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return false
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}
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if instr != opcode.PUSHBYTES33 {
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break
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}
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nkeys++
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if nkeys > MaxArraySize {
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return false
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}
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}
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if nkeys < nsigs {
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return false
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}
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nkeys2, ok := getNumOfThingsFromInstr(instr, param)
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if !ok {
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return false
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}
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if nkeys2 != nkeys {
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return false
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}
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instr, _, err = ctx.Next()
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if err != nil || instr != opcode.CHECKMULTISIG {
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return false
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}
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instr, _, err = ctx.Next()
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if err != nil || instr != opcode.RET || ctx.ip != len(script) {
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return false
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}
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return true
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}
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// IsSignatureContract checks whether the passed script is a signature check
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// contract.
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func IsSignatureContract(script []byte) bool {
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ctx := NewContext(script)
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instr, _, err := ctx.Next()
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if err != nil || instr != opcode.PUSHBYTES33 {
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return false
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}
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instr, _, err = ctx.Next()
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if err != nil || instr != opcode.CHECKSIG {
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return false
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}
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instr, _, err = ctx.Next()
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if err != nil || instr != opcode.RET || ctx.ip != len(script) {
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return false
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}
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return true
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}
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// IsStandardContract checks whether the passed script is a signature or
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// multi-signature contract.
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func IsStandardContract(script []byte) bool {
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return IsSignatureContract(script) || IsMultiSigContract(script)
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}
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