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gitea/vendor/github.com/mschoch/smat/actionseq.go

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2018-05-19 20:49:46 +08:00
// Copyright (c) 2016 Marty Schoch
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the
// License. You may obtain a copy of the License at
// http://www.apache.org/licenses/LICENSE-2.0
// Unless required by applicable law or agreed to in writing,
// software distributed under the License is distributed on an "AS
// IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either
// express or implied. See the License for the specific language
// governing permissions and limitations under the License.
package smat
// ActionSeq represents a sequence of actions, used for populating a corpus
// of byte sequences for the corresponding fuzz tests
type ActionSeq []ActionID
// ByteEncoding runs the FSM to produce a byte sequence to trigger the
// desired action
func (a ActionSeq) ByteEncoding(ctx Context, setup, teardown ActionID, actionMap ActionMap) ([]byte, error) {
setupFunc, teardownFunc, err := actionMap.findSetupTeardown(setup, teardown)
if err != nil {
return nil, err
}
state, err := setupFunc(ctx)
if err != nil {
return nil, err
}
defer func() {
_, _ = teardownFunc(ctx)
}()
var rv []byte
for _, actionID := range a {
b, err := probeStateForAction(state, actionID)
if err != nil {
return nil, err
}
rv = append(rv, b)
action, ok := actionMap[actionID]
if !ok {
continue
}
state, err = action(ctx)
if err != nil {
return nil, err
}
}
return rv, nil
}
func probeStateForAction(state State, actionID ActionID) (byte, error) {
for i := 0; i < 256; i++ {
nextActionID := state(byte(i))
if nextActionID == actionID {
return byte(i), nil
}
}
return 0, ErrActionNotPossible
}