From fc170098e9e21afe4d1b592b746c97fc5f8cccd9 Mon Sep 17 00:00:00 2001
From: Gregory Eremin <g@erem.in>
Date: Mon, 23 Feb 2015 20:07:19 +0700
Subject: [PATCH] One buffer fits all

---
 buffer/buffer.go    | 50 +++++++++++++++++++++++++++++++++++++++++++++
 buffer/bufferer.go  |  7 -------
 buffer/bytes.go     | 34 ------------------------------
 buffer/stream.go    | 37 ---------------------------------
 lexer/lexer.go      |  6 +++---
 lexer/lexer_test.go |  4 ++--
 main.go             | 15 +++++++++++++-
 parser/parser.go    |  2 +-
 8 files changed, 70 insertions(+), 85 deletions(-)
 create mode 100644 buffer/buffer.go
 delete mode 100644 buffer/bufferer.go
 delete mode 100644 buffer/bytes.go
 delete mode 100644 buffer/stream.go

diff --git a/buffer/buffer.go b/buffer/buffer.go
new file mode 100644
index 0000000..b9c74fa
--- /dev/null
+++ b/buffer/buffer.go
@@ -0,0 +1,50 @@
+package buffer
+
+import (
+	"bufio"
+	"bytes"
+	"io"
+)
+
+type (
+	Buffer struct {
+		input *bufio.Reader
+		ready chan rune
+	}
+)
+
+func NewBytesBuffer(b []byte) *Buffer {
+	return NewReaderBuffer(bytes.NewReader(b))
+}
+
+func NewReaderBuffer(rd io.Reader) *Buffer {
+	return New(bufio.NewReader(rd))
+}
+
+func New(input *bufio.Reader) *Buffer {
+	b := &Buffer{
+		input: input,
+		ready: make(chan rune, 100),
+	}
+	go b.stream()
+	return b
+}
+
+func (b *Buffer) Next() rune {
+	if next, ok := <-b.ready; ok {
+		return next
+	} else {
+		return 0
+	}
+}
+
+func (b *Buffer) stream() {
+	for {
+		if r, _, err := b.input.ReadRune(); err != nil {
+			close(b.ready)
+			break
+		} else {
+			b.ready <- r
+		}
+	}
+}
diff --git a/buffer/bufferer.go b/buffer/bufferer.go
deleted file mode 100644
index 1c34ae4..0000000
--- a/buffer/bufferer.go
+++ /dev/null
@@ -1,7 +0,0 @@
-package buffer
-
-type (
-	Bufferer interface {
-		Next() rune
-	}
-)
diff --git a/buffer/bytes.go b/buffer/bytes.go
deleted file mode 100644
index 5f43595..0000000
--- a/buffer/bytes.go
+++ /dev/null
@@ -1,34 +0,0 @@
-package buffer
-
-import (
-	"bytes"
-	"unicode/utf8"
-)
-
-type (
-	BytesBuffer struct {
-		input []byte
-		size  uint64
-		pos   uint64
-	}
-)
-
-func NewBytesBuffer(input []byte) *BytesBuffer {
-	return &BytesBuffer{
-		input: input,
-		size:  uint64(len(input)),
-	}
-}
-
-func (b *BytesBuffer) Next() rune {
-	var buf bytes.Buffer
-	for b.pos < b.size {
-		buf.WriteByte(b.input[b.pos])
-		b.pos++
-		if ok := utf8.FullRune(buf.Bytes()); ok {
-			r, _ := utf8.DecodeRune(buf.Bytes())
-			return r
-		}
-	}
-	return 0
-}
diff --git a/buffer/stream.go b/buffer/stream.go
deleted file mode 100644
index f274a93..0000000
--- a/buffer/stream.go
+++ /dev/null
@@ -1,37 +0,0 @@
-package buffer
-
-import (
-	"bytes"
-	"io"
-	"unicode/utf8"
-)
-
-type (
-	StreamBuffer struct {
-		input io.Reader
-	}
-)
-
-func NewStreamBuffer(input io.Reader) *StreamBuffer {
-	return &StreamBuffer{
-		input: input,
-	}
-}
-
-func (b *StreamBuffer) Next() rune {
-	var (
-		buf bytes.Buffer
-	)
-	for {
-		rbuf := make([]byte, 1)
-		if n, err := b.input.Read(rbuf); n != 1 || err != nil {
-			return 0
-		}
-		buf.Write(rbuf)
-		if ok := utf8.FullRune(buf.Bytes()); ok {
-			r, _ := utf8.DecodeRune(buf.Bytes())
-			return r
-		}
-	}
-	return 0
-}
diff --git a/lexer/lexer.go b/lexer/lexer.go
index 858235d..955de20 100644
--- a/lexer/lexer.go
+++ b/lexer/lexer.go
@@ -12,7 +12,7 @@ import (
 type (
 	// Holds the state of the scanner
 	Lexer struct {
-		input     buffer.Bufferer
+		input     *buffer.Buffer
 		stack     []rune    // Lexer stack
 		pos       int       // Current stack position
 		lineNum   int       // Line number
@@ -59,10 +59,10 @@ const (
 )
 
 // Creates a new scanner for the input buffer
-func New(input buffer.Bufferer) *Lexer {
+func New(input *buffer.Buffer) *Lexer {
 	return &Lexer{
 		input:   input,
-		items:   make(chan Item),
+		items:   make(chan Item, 100),
 		lineNum: 1,
 		colNum:  0,
 	}
diff --git a/lexer/lexer_test.go b/lexer/lexer_test.go
index a87adce..d23a60e 100644
--- a/lexer/lexer_test.go
+++ b/lexer/lexer_test.go
@@ -152,8 +152,8 @@ func compare(t *testing.T, reality, expectations []Item) {
 	}
 }
 
-func lex(json string) []Item {
-	buf := buffer.NewBytesBuffer([]byte(json))
+func lex(jstr string) []Item {
+	buf := buffer.NewBytesBuffer([]byte(jstr))
 	lex := New(buf)
 	go lex.Run()
 
diff --git a/main.go b/main.go
index da1303a..06524ab 100644
--- a/main.go
+++ b/main.go
@@ -6,6 +6,7 @@ import (
 	"os"
 	"strings"
 
+	"github.com/davecheney/profile"
 	"github.com/localhots/punk/buffer"
 	"github.com/localhots/punk/parser"
 )
@@ -14,8 +15,11 @@ func main() {
 	var (
 		sel     string
 		verbose bool
+		prof    string
 	)
+
 	flag.StringVar(&sel, "s", "", "Selector")
+	flag.StringVar(&prof, "prof", "", "Performance profiling output")
 	flag.BoolVar(&verbose, "v", false, "Verbose parsing")
 	flag.Parse()
 
@@ -24,15 +28,24 @@ func main() {
 		os.Exit(1)
 	}
 
+	if prof != "" {
+		defer profile.Start(&profile.Config{
+			CPUProfile:  true,
+			ProfilePath: prof,
+		}).Stop()
+	}
+
 	sels := strings.Split(sel, " ")
 	if len(sel) == 0 {
 		sels = []string{}
 	}
-	buf := buffer.NewStreamBuffer(os.Stdin)
+
+	buf := buffer.NewReaderBuffer(os.Stdin)
 	pars := parser.New(buf, sels)
 	if verbose {
 		pars.Debug()
 	}
+
 	res := pars.ParseStream()
 	for {
 		if m, ok := <-res; ok {
diff --git a/parser/parser.go b/parser/parser.go
index d33709f..58db05f 100644
--- a/parser/parser.go
+++ b/parser/parser.go
@@ -25,7 +25,7 @@ type (
 )
 
 // Creates a new parser
-func New(buf buffer.Bufferer, sels []string) *Parser {
+func New(buf *buffer.Buffer, sels []string) *Parser {
 	return &Parser{
 		lex: lexer.New(buf),
 		ctx: &context{