mirror of
https://github.com/nspcc-dev/neo-go.git
synced 2024-11-23 13:38:35 +00:00
110 lines
2.2 KiB
Go
110 lines
2.2 KiB
Go
package compiler
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import (
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"bytes"
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"encoding/binary"
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"errors"
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"fmt"
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"io"
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"math/big"
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"github.com/CityOfZion/neo-go/pkg/util"
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"github.com/CityOfZion/neo-go/pkg/vm"
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)
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func emit(w *bytes.Buffer, op vm.Opcode, b []byte) error {
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if err := w.WriteByte(byte(op)); err != nil {
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return err
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}
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_, err := w.Write(b)
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return err
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}
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func emitOpcode(w io.ByteWriter, op vm.Opcode) error {
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return w.WriteByte(byte(op))
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}
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func emitBool(w io.ByteWriter, ok bool) error {
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if ok {
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return emitOpcode(w, vm.Opusht)
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}
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return emitOpcode(w, vm.Opushf)
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}
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func emitInt(w *bytes.Buffer, i int64) error {
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if i == -1 {
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return emitOpcode(w, vm.Opushm1)
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}
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if i == 0 {
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return emitOpcode(w, vm.Opushf)
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}
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if i > 0 && i < 16 {
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val := vm.Opcode(int(vm.Opush1) - 1 + int(i))
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return emitOpcode(w, val)
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}
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bInt := big.NewInt(i)
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val := util.ArrayReverse(bInt.Bytes())
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return emitBytes(w, val)
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}
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func emitString(w *bytes.Buffer, s string) error {
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return emitBytes(w, []byte(s))
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}
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func emitBytes(w *bytes.Buffer, b []byte) error {
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var (
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err error
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n = len(b)
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)
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switch {
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case n <= int(vm.Opushbytes75):
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return emit(w, vm.Opcode(n), b)
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case n < 0x100:
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err = emit(w, vm.Opushdata1, []byte{byte(n)})
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case n < 0x10000:
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buf := make([]byte, 2)
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binary.LittleEndian.PutUint16(buf, uint16(n))
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err = emit(w, vm.Opushdata2, buf)
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default:
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buf := make([]byte, 4)
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binary.LittleEndian.PutUint32(buf, uint32(n))
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err = emit(w, vm.Opushdata4, buf)
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}
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if err != nil {
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return err
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}
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_, err = w.Write(b)
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return err
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}
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func emitSyscall(w *bytes.Buffer, api string) error {
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if len(api) == 0 {
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return errors.New("syscall api cannot be of length 0")
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}
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buf := make([]byte, len(api)+1)
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buf[0] = byte(len(api))
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copy(buf[1:], []byte(api))
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return emit(w, vm.Osyscall, buf)
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}
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func emitCall(w *bytes.Buffer, op vm.Opcode, label int16) error {
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return emitJmp(w, op, label)
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}
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func emitJmp(w *bytes.Buffer, op vm.Opcode, label int16) error {
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if !isOpcodeJmp(op) {
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return fmt.Errorf("opcode %s is not a jump or call type", op)
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}
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buf := make([]byte, 2)
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binary.LittleEndian.PutUint16(buf, uint16(label))
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return emit(w, op, buf)
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}
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func isOpcodeJmp(op vm.Opcode) bool {
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if op == vm.Ojmp || op == vm.Ojmpifnot || op == vm.Ojmpif || op == vm.Ocall {
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return true
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}
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return false
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}
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