/
brain_file.go
209 lines (180 loc) · 4.41 KB
/
brain_file.go
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package ghal
import (
"bytes"
"fmt"
"io"
"io/ioutil"
"os"
"github.com/vmihailenco/msgpack"
)
// LoadBrain reads a serialized brain from the given reader, which must
// be in the format created by Brain.Save.
func LoadBrain(r io.Reader) (*Brain, error) {
var fb fBrain
src, err := ioutil.ReadAll(r)
if err != nil {
return nil, err
}
if len(src) < 4 || !bytes.Equal(src[:4], fMagic) {
return nil, fmt.Errorf("not a brain file")
}
err = msgpack.Unmarshal(src[4:], &fb)
if err != nil {
return nil, fmt.Errorf("invalid brain file: %s", err)
}
if fb.ChainLen != chainLen {
return nil, fmt.Errorf("wrong chain length %d; need %d", fb.ChainLen, chainLen)
}
ret := NewBrain()
wordByIdx := func(i fIndex) Word {
if int(i) >= len(fb.Words) || i < 0 {
return Word{} // invalid
}
return Word{
Text: fb.Words[i].Text,
Tag: fb.Words[i].Tag,
}
}
for i, fc := range fb.Chains {
if got, want := len(fc.Words), chainLen; got != want {
return nil, fmt.Errorf("chain %d has wrong length %d; need %d", i, got, want)
}
var c chain
for i, wi := range fc.Words {
c[i] = wordByIdx(wi)
}
ret.chains.Add(c)
for _, w := range c {
if _, exists := ret.wordChains[w]; !exists {
ret.wordChains[w] = make(chainSet)
}
ret.wordChains[w].Add(c)
}
if _, exists := ret.wordsAfter[c]; !exists {
ret.wordsAfter[c] = make(WordSet)
}
if _, exists := ret.wordsBefore[c]; !exists {
ret.wordsBefore[c] = make(WordSet)
}
for _, wi := range fc.WordsAfter {
ret.wordsAfter[c].Add(wordByIdx(wi))
}
for _, wi := range fc.WordsBefore {
ret.wordsBefore[c].Add(wordByIdx(wi))
}
if fc.CanStart {
ret.startChains.Add(c)
}
if fc.CanEnd {
ret.endChains.Add(c)
}
}
return ret, nil
}
// Save writes a snapshot of the receiving brain's contents into the given
// writer in a binary format that can be reloaded later with LoadBrain.
func (b *Brain) Save(w io.Writer) error {
b.mut.RLock()
defer b.mut.RUnlock()
var fb fBrain
fb.ChainLen = chainLen
fb.Chains = make([]fChain, 0, len(b.chains))
fb.Words = make([]fWord, 0, len(b.wordChains))
wordIdxs := map[Word]fIndex{}
wordIdx := func(w Word) fIndex {
wIdx, exists := wordIdxs[w]
if !exists {
wIdx = fIndex(len(fb.Words))
wordIdxs[w] = wIdx
fb.Words = append(fb.Words, fWord{
Tag: w.Tag,
Text: w.Text,
})
}
return wIdx
}
for c := range b.chains {
var fc fChain
wds := make(fIndices, chainLen)
for i, w := range c {
wds[i] = wordIdx(w)
}
fc.Words = wds
for w := range b.wordsAfter[c] {
fc.WordsAfter = append(fc.WordsAfter, wordIdx(w))
}
for w := range b.wordsBefore[c] {
fc.WordsBefore = append(fc.WordsBefore, wordIdx(w))
}
fc.CanStart = b.startChains.Has(c)
fc.CanEnd = b.endChains.Has(c)
fb.Chains = append(fb.Chains, fc)
}
src, err := msgpack.Marshal(&fb)
if err != nil {
return err
}
_, err = w.Write(fMagic)
if err != nil {
return err
}
_, err = w.Write(src)
return err
}
// LoadBrainFile is like LoadBrain but it first opens the given filename
// and then reads data from it.
func LoadBrainFile(filename string) (*Brain, error) {
f, err := os.Open(filename)
if err != nil {
return nil, err
}
return LoadBrain(f)
}
// SaveFile is like Save but it creates a file with the given filename
// and then writes the data to it.
func (b *Brain) SaveFile(filename string) error {
f, err := os.Create(filename)
if err != nil {
return err
}
return b.Save(f)
}
var fMagic = []byte{'Q', 'W', 'O', 'K'}
type fBrain struct {
ChainLen int64 `msgpack:"chainLen"`
// indices into these lists are used in the other structures to keep the
// file format relatively compact, storing each distinct word and chain
// only once in the file.
Chains []fChain `msgpack:"chains"`
Words []fWord `msgpack:"words"`
}
type fChain struct {
Words fIndices `msgpack:"w"`
WordsAfter fIndices `msgpack:"a"`
WordsBefore fIndices `msgpack:"b"`
CanStart bool `msgpack:"s"`
CanEnd bool `msgpack:"e"`
}
type fWord struct {
Tag string `msgpack:"a"`
Text string `msgpack:"e"`
}
var (
_ msgpack.Marshaler = (*fWord)(nil)
_ msgpack.Unmarshaler = (*fWord)(nil)
)
type fIndex int64
type fIndices []fIndex
func (w fWord) MarshalMsgpack() ([]byte, error) {
return msgpack.Marshal([...]string{w.Text, w.Tag})
}
func (w *fWord) UnmarshalMsgpack(src []byte) error {
var v [2]string
err := msgpack.Unmarshal(src, &v)
if err != nil {
return err
}
w.Text = v[0]
w.Tag = v[1]
return nil
}