98 lines
2.1 KiB
Go
98 lines
2.1 KiB
Go
package vm
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import (
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"encoding/binary"
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)
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func getNumOfThingsFromInstr(instr Instruction, param []byte) (int, bool) {
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var nthings int
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switch instr {
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case PUSH1, PUSH2, PUSH3, PUSH4, PUSH5, PUSH6, PUSH7, PUSH8,
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PUSH9, PUSH10, PUSH11, PUSH12, PUSH13, PUSH14, PUSH15, PUSH16:
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nthings = int(instr-PUSH1) + 1
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case PUSHBYTES1:
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nthings = int(param[0])
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case 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 != 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 != 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 != 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 != 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 != 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 != 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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