khenaidoo | ab1f7bd | 2019-11-14 14:00:27 -0500 | [diff] [blame] | 1 | package jsoniter |
| 2 | |
| 3 | import "fmt" |
| 4 | |
| 5 | // ReadNil reads a json object as nil and |
| 6 | // returns whether it's a nil or not |
| 7 | func (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 |
| 18 | func (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. |
| 34 | func (iter *Iterator) SkipAndReturnBytes() []byte { |
| 35 | iter.startCapture(iter.head) |
| 36 | iter.Skip() |
| 37 | return iter.stopCapture() |
| 38 | } |
| 39 | |
| 40 | // SkipAndAppendBytes skips next JSON element and appends its content to |
| 41 | // buffer, returning the result. |
| 42 | func (iter *Iterator) SkipAndAppendBytes(buf []byte) []byte { |
| 43 | iter.startCaptureTo(buf, iter.head) |
| 44 | iter.Skip() |
| 45 | return iter.stopCapture() |
| 46 | } |
| 47 | |
| 48 | func (iter *Iterator) startCaptureTo(buf []byte, captureStartedAt int) { |
| 49 | if iter.captured != nil { |
| 50 | panic("already in capture mode") |
| 51 | } |
| 52 | iter.captureStartedAt = captureStartedAt |
| 53 | iter.captured = buf |
| 54 | } |
| 55 | |
| 56 | func (iter *Iterator) startCapture(captureStartedAt int) { |
| 57 | iter.startCaptureTo(make([]byte, 0, 32), captureStartedAt) |
| 58 | } |
| 59 | |
| 60 | func (iter *Iterator) stopCapture() []byte { |
| 61 | if iter.captured == nil { |
| 62 | panic("not in capture mode") |
| 63 | } |
| 64 | captured := iter.captured |
| 65 | remaining := iter.buf[iter.captureStartedAt:iter.head] |
| 66 | iter.captureStartedAt = -1 |
| 67 | iter.captured = nil |
| 68 | return append(captured, remaining...) |
| 69 | } |
| 70 | |
| 71 | // Skip skips a json object and positions to relatively the next json object |
| 72 | func (iter *Iterator) Skip() { |
| 73 | c := iter.nextToken() |
| 74 | switch c { |
| 75 | case '"': |
| 76 | iter.skipString() |
| 77 | case 'n': |
| 78 | iter.skipThreeBytes('u', 'l', 'l') // null |
| 79 | case 't': |
| 80 | iter.skipThreeBytes('r', 'u', 'e') // true |
| 81 | case 'f': |
| 82 | iter.skipFourBytes('a', 'l', 's', 'e') // false |
| 83 | case '0': |
| 84 | iter.unreadByte() |
| 85 | iter.ReadFloat32() |
| 86 | case '-', '1', '2', '3', '4', '5', '6', '7', '8', '9': |
| 87 | iter.skipNumber() |
| 88 | case '[': |
| 89 | iter.skipArray() |
| 90 | case '{': |
| 91 | iter.skipObject() |
| 92 | default: |
| 93 | iter.ReportError("Skip", fmt.Sprintf("do not know how to skip: %v", c)) |
| 94 | return |
| 95 | } |
| 96 | } |
| 97 | |
| 98 | func (iter *Iterator) skipFourBytes(b1, b2, b3, b4 byte) { |
| 99 | if iter.readByte() != b1 { |
| 100 | iter.ReportError("skipFourBytes", fmt.Sprintf("expect %s", string([]byte{b1, b2, b3, b4}))) |
| 101 | return |
| 102 | } |
| 103 | if iter.readByte() != b2 { |
| 104 | iter.ReportError("skipFourBytes", fmt.Sprintf("expect %s", string([]byte{b1, b2, b3, b4}))) |
| 105 | return |
| 106 | } |
| 107 | if iter.readByte() != b3 { |
| 108 | iter.ReportError("skipFourBytes", fmt.Sprintf("expect %s", string([]byte{b1, b2, b3, b4}))) |
| 109 | return |
| 110 | } |
| 111 | if iter.readByte() != b4 { |
| 112 | iter.ReportError("skipFourBytes", fmt.Sprintf("expect %s", string([]byte{b1, b2, b3, b4}))) |
| 113 | return |
| 114 | } |
| 115 | } |
| 116 | |
| 117 | func (iter *Iterator) skipThreeBytes(b1, b2, b3 byte) { |
| 118 | if iter.readByte() != b1 { |
| 119 | iter.ReportError("skipThreeBytes", fmt.Sprintf("expect %s", string([]byte{b1, b2, b3}))) |
| 120 | return |
| 121 | } |
| 122 | if iter.readByte() != b2 { |
| 123 | iter.ReportError("skipThreeBytes", fmt.Sprintf("expect %s", string([]byte{b1, b2, b3}))) |
| 124 | return |
| 125 | } |
| 126 | if iter.readByte() != b3 { |
| 127 | iter.ReportError("skipThreeBytes", fmt.Sprintf("expect %s", string([]byte{b1, b2, b3}))) |
| 128 | return |
| 129 | } |
| 130 | } |