mirror of
https://github.com/nspcc-dev/neo-go.git
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119 lines
2.7 KiB
Go
119 lines
2.7 KiB
Go
package compiler
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import (
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"encoding/binary"
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"errors"
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"fmt"
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"math/big"
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"github.com/CityOfZion/neo-go/pkg/io"
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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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// emit a VM Instruction with data to the given buffer.
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func emit(w *io.BufBinWriter, instr vm.Instruction, b []byte) {
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w.WriteLE(byte(instr))
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w.WriteVarBytes(b)
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}
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// emitOpcode emits a single VM Instruction the given buffer.
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func emitOpcode(w *io.BufBinWriter, instr vm.Instruction) {
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w.WriteLE(byte(instr))
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}
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// emitBool emits a bool type the given buffer.
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func emitBool(w *io.BufBinWriter, ok bool) {
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if ok {
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emitOpcode(w, vm.PUSHT)
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return
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}
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emitOpcode(w, vm.PUSHF)
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}
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// emitInt emits a int type to the given buffer.
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func emitInt(w *io.BufBinWriter, i int64) {
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switch {
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case i == -1:
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emitOpcode(w, vm.PUSHM1)
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return
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case i == 0:
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emitOpcode(w, vm.PUSHF)
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return
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case i > 0 && i < 16:
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val := vm.Instruction(int(vm.PUSH1) - 1 + int(i))
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emitOpcode(w, val)
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return
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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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emitBytes(w, val)
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}
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// emitString emits a string to the given buffer.
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func emitString(w *io.BufBinWriter, s string) {
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emitBytes(w, []byte(s))
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}
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// emitBytes emits a byte array to the given buffer.
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func emitBytes(w *io.BufBinWriter, b []byte) {
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n := len(b)
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switch {
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case n <= int(vm.PUSHBYTES75):
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emit(w, vm.Instruction(n), b)
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return
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case n < 0x100:
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emit(w, vm.PUSHDATA1, []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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emit(w, vm.PUSHDATA2, 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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emit(w, vm.PUSHDATA4, buf)
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if w.Err != nil {
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return
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}
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}
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w.WriteBytes(b)
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}
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// emitSyscall emits the syscall API to the given buffer.
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// Syscall API string cannot be 0.
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func emitSyscall(w *io.BufBinWriter, api string) {
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if len(api) == 0 {
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w.Err = errors.New("syscall api cannot be of length 0")
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return
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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:], api)
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emit(w, vm.SYSCALL, buf)
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}
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// emitCall emits a call Instruction with label to the given buffer.
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func emitCall(w *io.BufBinWriter, instr vm.Instruction, label int16) {
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emitJmp(w, instr, label)
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}
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// emitJmp emits a jump Instruction along with label to the given buffer.
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func emitJmp(w *io.BufBinWriter, instr vm.Instruction, label int16) {
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if !isInstrJmp(instr) {
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w.Err = fmt.Errorf("opcode %s is not a jump or call type", instr)
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return
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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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emit(w, instr, buf)
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}
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func isInstrJmp(instr vm.Instruction) bool {
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if instr == vm.JMP || instr == vm.JMPIFNOT || instr == vm.JMPIF || instr == vm.CALL {
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return true
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}
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return false
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}
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