1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
|
package exifundefined
import (
"bytes"
"fmt"
"encoding/binary"
"github.com/dsoprea/go-logging"
"github.com/dsoprea/go-exif/v3/common"
)
type Tag8828Oecf struct {
Columns uint16
Rows uint16
ColumnNames []string
Values []exifcommon.SignedRational
}
func (oecf Tag8828Oecf) String() string {
return fmt.Sprintf("Tag8828Oecf<COLUMNS=(%d) ROWS=(%d)>", oecf.Columns, oecf.Rows)
}
func (oecf Tag8828Oecf) EncoderName() string {
return "Codec8828Oecf"
}
type Codec8828Oecf struct {
}
func (Codec8828Oecf) Encode(value interface{}, byteOrder binary.ByteOrder) (encoded []byte, unitCount uint32, err error) {
defer func() {
if state := recover(); state != nil {
err = log.Wrap(state.(error))
}
}()
// TODO(dustin): Add test
oecf, ok := value.(Tag8828Oecf)
if ok == false {
log.Panicf("can only encode a Tag8828Oecf")
}
b := new(bytes.Buffer)
err = binary.Write(b, byteOrder, oecf.Columns)
log.PanicIf(err)
err = binary.Write(b, byteOrder, oecf.Rows)
log.PanicIf(err)
for _, name := range oecf.ColumnNames {
_, err := b.Write([]byte(name))
log.PanicIf(err)
_, err = b.Write([]byte{0})
log.PanicIf(err)
}
ve := exifcommon.NewValueEncoder(byteOrder)
ed, err := ve.Encode(oecf.Values)
log.PanicIf(err)
_, err = b.Write(ed.Encoded)
log.PanicIf(err)
return b.Bytes(), uint32(b.Len()), nil
}
func (Codec8828Oecf) Decode(valueContext *exifcommon.ValueContext) (value EncodeableValue, err error) {
defer func() {
if state := recover(); state != nil {
err = log.Wrap(state.(error))
}
}()
// TODO(dustin): Add test using known good data.
valueContext.SetUndefinedValueType(exifcommon.TypeByte)
valueBytes, err := valueContext.ReadBytes()
log.PanicIf(err)
oecf := Tag8828Oecf{}
oecf.Columns = valueContext.ByteOrder().Uint16(valueBytes[0:2])
oecf.Rows = valueContext.ByteOrder().Uint16(valueBytes[2:4])
columnNames := make([]string, oecf.Columns)
// startAt is where the current column name starts.
startAt := 4
// offset is our current position.
offset := startAt
currentColumnNumber := uint16(0)
for currentColumnNumber < oecf.Columns {
if valueBytes[offset] == 0 {
columnName := string(valueBytes[startAt:offset])
if len(columnName) == 0 {
log.Panicf("SFR column (%d) has zero length", currentColumnNumber)
}
columnNames[currentColumnNumber] = columnName
currentColumnNumber++
offset++
startAt = offset
continue
}
offset++
}
oecf.ColumnNames = columnNames
rawRationalBytes := valueBytes[offset:]
rationalSize := exifcommon.TypeSignedRational.Size()
if len(rawRationalBytes)%rationalSize > 0 {
log.Panicf("OECF signed-rationals not aligned: (%d) %% (%d) > 0", len(rawRationalBytes), rationalSize)
}
rationalCount := len(rawRationalBytes) / rationalSize
parser := new(exifcommon.Parser)
byteOrder := valueContext.ByteOrder()
items, err := parser.ParseSignedRationals(rawRationalBytes, uint32(rationalCount), byteOrder)
log.PanicIf(err)
oecf.Values = items
return oecf, nil
}
func init() {
registerDecoder(
exifcommon.IfdExifStandardIfdIdentity.UnindexedString(),
0x8828,
Codec8828Oecf{})
}
|
