rename

feature_iter.go

@@ -0,0 +1,273 @@
+package jsoniter
+
+import (
+	"encoding/base64"
+	"fmt"
+	"io"
+)
+
+type ValueType int
+
+const (
+	Invalid ValueType = iota
+	String
+	Number
+	Nil
+	Bool
+	Array
+	Object
+)
+
+var hexDigits []byte
+var valueTypes []ValueType
+
+func init() {
+	hexDigits = make([]byte, 256)
+	for i := 0; i < len(hexDigits); i++ {
+		hexDigits[i] = 255
+	}
+	for i := '0'; i <= '9'; i++ {
+		hexDigits[i] = byte(i - '0')
+	}
+	for i := 'a'; i <= 'f'; i++ {
+		hexDigits[i] = byte((i - 'a') + 10)
+	}
+	for i := 'A'; i <= 'F'; i++ {
+		hexDigits[i] = byte((i - 'A') + 10)
+	}
+	valueTypes = make([]ValueType, 256)
+	for i := 0; i < len(valueTypes); i++ {
+		valueTypes[i] = Invalid
+	}
+	valueTypes['"'] = String
+	valueTypes['-'] = Number
+	valueTypes['0'] = Number
+	valueTypes['1'] = Number
+	valueTypes['2'] = Number
+	valueTypes['3'] = Number
+	valueTypes['4'] = Number
+	valueTypes['5'] = Number
+	valueTypes['6'] = Number
+	valueTypes['7'] = Number
+	valueTypes['8'] = Number
+	valueTypes['9'] = Number
+	valueTypes['t'] = Bool
+	valueTypes['f'] = Bool
+	valueTypes['n'] = Nil
+	valueTypes['['] = Array
+	valueTypes['{'] = Object
+}
+
+// Iterator is a fast and flexible JSON parser
+type Iterator struct {
+	reader io.Reader
+	buf    []byte
+	head   int
+	tail   int
+	Error  error
+}
+
+// Create creates an empty Iterator instance
+func NewIterator() *Iterator {
+	return &Iterator{
+		reader: nil,
+		buf:    nil,
+		head:   0,
+		tail:   0,
+	}
+}
+
+// Parse parses a json buffer in io.Reader into an Iterator instance
+func Parse(reader io.Reader, bufSize int) *Iterator {
+	return &Iterator{
+		reader: reader,
+		buf:    make([]byte, bufSize),
+		head:   0,
+		tail:   0,
+	}
+}
+
+// ParseBytes parses a json byte slice into an Iterator instance
+func ParseBytes(input []byte) *Iterator {
+	return &Iterator{
+		reader: nil,
+		buf:    input,
+		head:   0,
+		tail:   len(input),
+	}
+}
+
+// ParseString parses a json string into an Iterator instance
+func ParseString(input string) *Iterator {
+	return ParseBytes([]byte(input))
+}
+
+// Reset can reset an Iterator instance for another json buffer in io.Reader
+func (iter *Iterator) Reset(reader io.Reader) *Iterator {
+	iter.reader = reader
+	iter.head = 0
+	iter.tail = 0
+	return iter
+}
+
+// ResetBytes can reset an Iterator instance for another json byte slice
+func (iter *Iterator) ResetBytes(input []byte) *Iterator {
+	iter.reader = nil
+	iter.Error = nil
+	iter.buf = input
+	iter.head = 0
+	iter.tail = len(input)
+	return iter
+}
+
+// WhatIsNext gets ValueType of relatively next json object
+func (iter *Iterator) WhatIsNext() ValueType {
+	valueType := valueTypes[iter.nextToken()]
+	iter.unreadByte()
+	return valueType
+}
+
+func (iter *Iterator) skipWhitespacesWithoutLoadMore() bool {
+	for i := iter.head; i < iter.tail; i++ {
+		c := iter.buf[i]
+		switch c {
+		case ' ', '\n', '\t', '\r':
+			continue
+		}
+		iter.head = i
+		return false
+	}
+	return true
+}
+
+func (iter *Iterator) nextToken() byte {
+	// a variation of skip whitespaces, returning the next non-whitespace token
+	for {
+		for i := iter.head; i < iter.tail; i++ {
+			c := iter.buf[i]
+			switch c {
+			case ' ', '\n', '\t', '\r':
+				continue
+			}
+			iter.head = i + 1
+			return c
+		}
+		if !iter.loadMore() {
+			return 0
+		}
+	}
+}
+
+func (iter *Iterator) reportError(operation string, msg string) {
+	if iter.Error != nil {
+		return
+	}
+	peekStart := iter.head - 10
+	if peekStart < 0 {
+		peekStart = 0
+	}
+	iter.Error = fmt.Errorf("%s: %s, parsing %v ...%s... at %s", operation, msg, iter.head,
+		string(iter.buf[peekStart:iter.head]), string(iter.buf[0:iter.tail]))
+}
+
+// CurrentBuffer gets current buffer as string
+func (iter *Iterator) CurrentBuffer() string {
+	peekStart := iter.head - 10
+	if peekStart < 0 {
+		peekStart = 0
+	}
+	return fmt.Sprintf("parsing %v ...|%s|... at %s", iter.head,
+		string(iter.buf[peekStart:iter.head]), string(iter.buf[0:iter.tail]))
+}
+
+func (iter *Iterator) readByte() (ret byte) {
+	if iter.head == iter.tail {
+		if iter.loadMore() {
+			ret = iter.buf[iter.head]
+			iter.head++
+			return ret
+		}
+		return 0
+	}
+	ret = iter.buf[iter.head]
+	iter.head++
+	return ret
+}
+
+func (iter *Iterator) loadMore() bool {
+	if iter.reader == nil {
+		iter.Error = io.EOF
+		return false
+	}
+	for {
+		n, err := iter.reader.Read(iter.buf)
+		if n == 0 {
+			if err != nil {
+				iter.Error = err
+				return false
+			}
+		} else {
+			iter.head = 0
+			iter.tail = n
+			return true
+		}
+	}
+}
+
+func (iter *Iterator) unreadByte() {
+	if iter.head == 0 {
+		iter.reportError("unreadByte", "unread too many bytes")
+		return
+	}
+	iter.head--
+	return
+}
+
+func (iter *Iterator) Read() interface{} {
+	valueType := iter.WhatIsNext()
+	switch valueType {
+	case String:
+		return iter.ReadString()
+	case Number:
+		return iter.ReadFloat64()
+	case Nil:
+		iter.skipFixedBytes(4) // null
+		return nil
+	case Bool:
+		return iter.ReadBool()
+	case Array:
+		arr := []interface{}{}
+		iter.ReadArrayCB(func(iter *Iterator) bool {
+			arr = append(arr, iter.Read())
+			return true
+		})
+		return arr
+	case Object:
+		obj := map[string]interface{}{}
+		iter.ReadObjectCB(func(Iter *Iterator, field string) bool {
+			obj[field] = iter.Read()
+			return true
+		})
+		return obj
+	default:
+		iter.reportError("Read", fmt.Sprintf("unexpected value type: %v", valueType))
+		return nil
+	}
+}
+
+// ReadBase64 reads a json object as Base64 in byte slice
+func (iter *Iterator) ReadBase64() (ret []byte) {
+	src := iter.ReadStringAsSlice()
+	if iter.Error != nil {
+		return
+	}
+	b64 := base64.StdEncoding
+	ret = make([]byte, b64.DecodedLen(len(src)))
+	n, err := b64.Decode(ret, src)
+	if err != nil {
+		iter.Error = err
+		return
+	}
+	return ret[:n]
+}
+