3173bf345e
Implement `StringFromOpcode` function that tries to retrieve `string` to `Op`. Add a comment about neo-go source code that is used for implementation of converters. Signed-off-by: Leonard Lyubich <leonard@nspcc.ru>
59 lines
1.4 KiB
Go
59 lines
1.4 KiB
Go
package event
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import (
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"fmt"
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"github.com/nspcc-dev/neo-go/pkg/encoding/bigint"
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"github.com/nspcc-dev/neo-go/pkg/vm/opcode"
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)
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// Op is wrapper over Neo VM's opcode
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// and its parameter.
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type Op struct {
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code opcode.Opcode
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param []byte
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}
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// Code returns Neo VM opcode.
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func (o Op) Code() opcode.Opcode {
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return o.code
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}
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// Param returns parameter of wrapped
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// Neo VM opcode.
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func (o Op) Param() []byte {
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return o.param
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}
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// Below are the functions which reverse the results of github.com/nspcc-dev/neo-go/pkg/vm/emit.Array function.
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// BytesFromOpcode tries to retrieve bytes from Op.
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func BytesFromOpcode(op Op) ([]byte, error) {
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switch code := op.Code(); code {
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case opcode.PUSHDATA1, opcode.PUSHDATA2, opcode.PUSHDATA4:
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return op.Param(), nil
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default:
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return nil, fmt.Errorf("unexpected ByteArray opcode %s", code)
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}
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}
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// IntFromOpcode tries to retrieve int from Op.
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func IntFromOpcode(op Op) (int64, error) {
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switch code := op.Code(); {
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case code == opcode.PUSHM1:
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return -1, nil
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case code >= opcode.PUSH0 && code <= opcode.PUSH16:
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return int64(code - opcode.PUSH0), nil
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case code <= opcode.PUSHINT256:
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return bigint.FromBytes(op.Param()).Int64(), nil
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default:
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return 0, fmt.Errorf("unexpected INT opcode %s", code)
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}
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}
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// StringFromOpcode tries to retrieve string from Op.
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func StringFromOpcode(op Op) (string, error) {
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// strings are emitted like bytes
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data, err := BytesFromOpcode(op)
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return string(data), err
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}
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