-
Notifications
You must be signed in to change notification settings - Fork 25
Commit
This commit does not belong to any branch on this repository, and may belong to a fork outside of the repository.
Merge pull request #34 from Stebalien/steb/optimize
Optimize decoding
- Loading branch information
Showing
8 changed files
with
359 additions
and
245 deletions.
There are no files selected for viewing
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,80 @@ | ||
| package typegen | ||
|
|
||
| import ( | ||
| "bufio" | ||
| "io" | ||
| ) | ||
|
|
||
| // BytePeeker combines the Reader and ByteScanner interfaces. | ||
| type BytePeeker interface { | ||
| io.Reader | ||
| io.ByteScanner | ||
| } | ||
|
|
||
| func GetPeeker(r io.Reader) BytePeeker { | ||
| if r, ok := r.(BytePeeker); ok { | ||
| return r | ||
| } | ||
| return &peeker{reader: r} | ||
| } | ||
|
|
||
| // peeker is a non-buffering BytePeeker. | ||
| type peeker struct { | ||
| reader io.Reader | ||
| peekState int | ||
| lastByte byte | ||
| } | ||
|
|
||
| const ( | ||
| peekEmpty = iota | ||
| peekSet | ||
| peekUnread | ||
| ) | ||
|
|
||
| func (p *peeker) Read(buf []byte) (n int, err error) { | ||
| // Read "nothing". I.e., read an error, maybe. | ||
| if len(buf) == 0 { | ||
| // There's something pending in the | ||
| if p.peekState == peekUnread { | ||
| return 0, nil | ||
| } | ||
| return p.reader.Read(nil) | ||
| } | ||
|
|
||
| if p.peekState == peekUnread { | ||
| buf[0] = p.lastByte | ||
| n, err = p.reader.Read(buf[1:]) | ||
| n += 1 | ||
| } else { | ||
| n, err = p.reader.Read(buf) | ||
| } | ||
| if n > 0 { | ||
| p.peekState = peekSet | ||
| p.lastByte = buf[n-1] | ||
| } | ||
| return n, err | ||
| } | ||
|
|
||
| func (p *peeker) ReadByte() (byte, error) { | ||
| if p.peekState == peekUnread { | ||
| p.peekState = peekSet | ||
| return p.lastByte, nil | ||
| } | ||
| var buf [1]byte | ||
| n, err := p.reader.Read(buf[:]) | ||
| if n == 0 { | ||
| return 0, err | ||
| } | ||
| b := buf[0] | ||
| p.lastByte = b | ||
| p.peekState = peekSet | ||
| return b, err | ||
| } | ||
|
|
||
| func (p *peeker) UnreadByte() error { | ||
| if p.peekState != peekSet { | ||
| return bufio.ErrInvalidUnreadByte | ||
| } | ||
| p.peekState = peekUnread | ||
| return nil | ||
| } |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
| Original file line number | Diff line number | Diff line change |
|---|---|---|
| @@ -0,0 +1,103 @@ | ||
| package typegen | ||
|
|
||
| import ( | ||
| "bufio" | ||
| "bytes" | ||
| "io" | ||
| "testing" | ||
| ) | ||
|
|
||
| func TestPeeker(t *testing.T) { | ||
| buf := bytes.NewBuffer([]byte{0, 1, 2, 3}) | ||
| p := peeker{reader: buf} | ||
| n, err := p.Read(nil) | ||
| if err != nil { | ||
| t.Fatal(err) | ||
| } | ||
| if n != 0 { | ||
| t.Fatal(err) | ||
| } | ||
|
|
||
| err = p.UnreadByte() | ||
| if err != bufio.ErrInvalidUnreadByte { | ||
| t.Fatal(err) | ||
| } | ||
|
|
||
| // read 2 bytes | ||
| var out [2]byte | ||
| n, err = p.Read(out[:]) | ||
| if err != nil { | ||
| t.Fatal(err) | ||
| } | ||
| if n != 2 { | ||
| t.Fatalf("expected 2 bytes, got %d", n) | ||
| } | ||
| if !bytes.Equal(out[:], []byte{0, 1}) { | ||
| t.Fatalf("unexpected output") | ||
| } | ||
|
|
||
| // unread that last byte and read it again. | ||
| err = p.UnreadByte() | ||
| if err != nil { | ||
| t.Fatal(err) | ||
| } | ||
| b, err := p.ReadByte() | ||
| if err != nil { | ||
| t.Fatal(err) | ||
| } | ||
| if b != 1 { | ||
| t.Fatal("expected 1") | ||
| } | ||
|
|
||
| // unread that last byte then read 2 | ||
| err = p.UnreadByte() | ||
| if err != nil { | ||
| t.Fatal(err) | ||
| } | ||
| n, err = p.Read(out[:]) | ||
| if err != nil { | ||
| t.Fatal(err) | ||
| } | ||
| if n != 2 { | ||
| t.Fatalf("expected 2 bytes, got %d", n) | ||
| } | ||
| if !bytes.Equal(out[:], []byte{1, 2}) { | ||
| t.Fatalf("unexpected output") | ||
| } | ||
|
|
||
| // read another byte | ||
| b, err = p.ReadByte() | ||
| if err != nil { | ||
| t.Fatal(err) | ||
| } | ||
| if b != 3 { | ||
| t.Fatal("expected 1") | ||
| } | ||
|
|
||
| // Should read eof at end. | ||
| n, err = p.Read(out[:]) | ||
| if err != io.EOF { | ||
| t.Fatal(err) | ||
| } | ||
| if n != 0 { | ||
| t.Fatal("should have been at end") | ||
| } | ||
| // should unread eof | ||
| err = p.UnreadByte() | ||
| if err != nil { | ||
| t.Fatal(err) | ||
| } | ||
|
|
||
| _, err = p.Read(nil) | ||
| if err != nil { | ||
| t.Fatal(err) | ||
| } | ||
|
|
||
| b, err = p.ReadByte() | ||
| if err != nil { | ||
| t.Fatal(err) | ||
| } | ||
| if b != 3 { | ||
| t.Fatal("expected 1") | ||
| } | ||
| } |
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
Oops, something went wrong.