iter_skip.go
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package jsoniter
import "fmt"
// ReadNil reads a json object as nil and
// returns whether it's a nil or not
func (iter *Iterator) ReadNil() (ret bool) {
c := iter.nextToken()
if c == 'n' {
iter.skipThreeBytes('u', 'l', 'l') // null
return true
}
iter.unreadByte()
return false
}
// ReadBool reads a json object as BoolValue
func (iter *Iterator) ReadBool() (ret bool) {
c := iter.nextToken()
if c == 't' {
iter.skipThreeBytes('r', 'u', 'e')
return true
}
if c == 'f' {
iter.skipFourBytes('a', 'l', 's', 'e')
return false
}
iter.ReportError("ReadBool", "expect t or f, but found "+string([]byte{c}))
return
}
// SkipAndReturnBytes skip next JSON element, and return its content as []byte.
// The []byte can be kept, it is a copy of data.
func (iter *Iterator) SkipAndReturnBytes() []byte {
iter.startCapture(iter.head)
iter.Skip()
return iter.stopCapture()
}
type captureBuffer struct {
startedAt int
captured []byte
}
func (iter *Iterator) startCapture(captureStartedAt int) {
if iter.captured != nil {
panic("already in capture mode")
}
iter.captureStartedAt = captureStartedAt
iter.captured = make([]byte, 0, 32)
}
func (iter *Iterator) stopCapture() []byte {
if iter.captured == nil {
panic("not in capture mode")
}
captured := iter.captured
remaining := iter.buf[iter.captureStartedAt:iter.head]
iter.captureStartedAt = -1
iter.captured = nil
if len(captured) == 0 {
copied := make([]byte, len(remaining))
copy(copied, remaining)
return copied
}
captured = append(captured, remaining...)
return captured
}
// Skip skips a json object and positions to relatively the next json object
func (iter *Iterator) Skip() {
c := iter.nextToken()
switch c {
case '"':
iter.skipString()
case 'n':
iter.skipThreeBytes('u', 'l', 'l') // null
case 't':
iter.skipThreeBytes('r', 'u', 'e') // true
case 'f':
iter.skipFourBytes('a', 'l', 's', 'e') // false
case '0':
iter.unreadByte()
iter.ReadFloat32()
case '-', '1', '2', '3', '4', '5', '6', '7', '8', '9':
iter.skipNumber()
case '[':
iter.skipArray()
case '{':
iter.skipObject()
default:
iter.ReportError("Skip", fmt.Sprintf("do not know how to skip: %v", c))
return
}
}
func (iter *Iterator) skipFourBytes(b1, b2, b3, b4 byte) {
if iter.readByte() != b1 {
iter.ReportError("skipFourBytes", fmt.Sprintf("expect %s", string([]byte{b1, b2, b3, b4})))
return
}
if iter.readByte() != b2 {
iter.ReportError("skipFourBytes", fmt.Sprintf("expect %s", string([]byte{b1, b2, b3, b4})))
return
}
if iter.readByte() != b3 {
iter.ReportError("skipFourBytes", fmt.Sprintf("expect %s", string([]byte{b1, b2, b3, b4})))
return
}
if iter.readByte() != b4 {
iter.ReportError("skipFourBytes", fmt.Sprintf("expect %s", string([]byte{b1, b2, b3, b4})))
return
}
}
func (iter *Iterator) skipThreeBytes(b1, b2, b3 byte) {
if iter.readByte() != b1 {
iter.ReportError("skipThreeBytes", fmt.Sprintf("expect %s", string([]byte{b1, b2, b3})))
return
}
if iter.readByte() != b2 {
iter.ReportError("skipThreeBytes", fmt.Sprintf("expect %s", string([]byte{b1, b2, b3})))
return
}
if iter.readByte() != b3 {
iter.ReportError("skipThreeBytes", fmt.Sprintf("expect %s", string([]byte{b1, b2, b3})))
return
}
}