1package jsoniter 2 3import "fmt" 4 5// ReadNil reads a json object as nil and 6// returns whether it's a nil or not 7func (iter *Iterator) ReadNil() (ret bool) { 8 c := iter.nextToken() 9 if c == 'n' { 10 iter.skipThreeBytes('u', 'l', 'l') // null 11 return true 12 } 13 iter.unreadByte() 14 return false 15} 16 17// ReadBool reads a json object as BoolValue 18func (iter *Iterator) ReadBool() (ret bool) { 19 c := iter.nextToken() 20 if c == 't' { 21 iter.skipThreeBytes('r', 'u', 'e') 22 return true 23 } 24 if c == 'f' { 25 iter.skipFourBytes('a', 'l', 's', 'e') 26 return false 27 } 28 iter.ReportError("ReadBool", "expect t or f, but found "+string([]byte{c})) 29 return 30} 31 32// SkipAndReturnBytes skip next JSON element, and return its content as []byte. 33// The []byte can be kept, it is a copy of data. 34func (iter *Iterator) SkipAndReturnBytes() []byte { 35 iter.startCapture(iter.head) 36 iter.Skip() 37 return iter.stopCapture() 38} 39 40type captureBuffer struct { 41 startedAt int 42 captured []byte 43} 44 45func (iter *Iterator) startCapture(captureStartedAt int) { 46 if iter.captured != nil { 47 panic("already in capture mode") 48 } 49 iter.captureStartedAt = captureStartedAt 50 iter.captured = make([]byte, 0, 32) 51} 52 53func (iter *Iterator) stopCapture() []byte { 54 if iter.captured == nil { 55 panic("not in capture mode") 56 } 57 captured := iter.captured 58 remaining := iter.buf[iter.captureStartedAt:iter.head] 59 iter.captureStartedAt = -1 60 iter.captured = nil 61 if len(captured) == 0 { 62 copied := make([]byte, len(remaining)) 63 copy(copied, remaining) 64 return copied 65 } 66 captured = append(captured, remaining...) 67 return captured 68} 69 70// Skip skips a json object and positions to relatively the next json object 71func (iter *Iterator) Skip() { 72 c := iter.nextToken() 73 switch c { 74 case '"': 75 iter.skipString() 76 case 'n': 77 iter.skipThreeBytes('u', 'l', 'l') // null 78 case 't': 79 iter.skipThreeBytes('r', 'u', 'e') // true 80 case 'f': 81 iter.skipFourBytes('a', 'l', 's', 'e') // false 82 case '0': 83 iter.unreadByte() 84 iter.ReadFloat32() 85 case '-', '1', '2', '3', '4', '5', '6', '7', '8', '9': 86 iter.skipNumber() 87 case '[': 88 iter.skipArray() 89 case '{': 90 iter.skipObject() 91 default: 92 iter.ReportError("Skip", fmt.Sprintf("do not know how to skip: %v", c)) 93 return 94 } 95} 96 97func (iter *Iterator) skipFourBytes(b1, b2, b3, b4 byte) { 98 if iter.readByte() != b1 { 99 iter.ReportError("skipFourBytes", fmt.Sprintf("expect %s", string([]byte{b1, b2, b3, b4}))) 100 return 101 } 102 if iter.readByte() != b2 { 103 iter.ReportError("skipFourBytes", fmt.Sprintf("expect %s", string([]byte{b1, b2, b3, b4}))) 104 return 105 } 106 if iter.readByte() != b3 { 107 iter.ReportError("skipFourBytes", fmt.Sprintf("expect %s", string([]byte{b1, b2, b3, b4}))) 108 return 109 } 110 if iter.readByte() != b4 { 111 iter.ReportError("skipFourBytes", fmt.Sprintf("expect %s", string([]byte{b1, b2, b3, b4}))) 112 return 113 } 114} 115 116func (iter *Iterator) skipThreeBytes(b1, b2, b3 byte) { 117 if iter.readByte() != b1 { 118 iter.ReportError("skipThreeBytes", fmt.Sprintf("expect %s", string([]byte{b1, b2, b3}))) 119 return 120 } 121 if iter.readByte() != b2 { 122 iter.ReportError("skipThreeBytes", fmt.Sprintf("expect %s", string([]byte{b1, b2, b3}))) 123 return 124 } 125 if iter.readByte() != b3 { 126 iter.ReportError("skipThreeBytes", fmt.Sprintf("expect %s", string([]byte{b1, b2, b3}))) 127 return 128 } 129} 130