encoder.go 2.9 KB

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  1. // Copyright 2013 ChaiShushan <chaishushan{AT}gmail.com>. All rights reserved.
  2. // Use of this source code is governed by a BSD-style
  3. // license that can be found in the LICENSE file.
  4. package mo
  5. import (
  6. "bytes"
  7. "encoding/binary"
  8. "sort"
  9. "strings"
  10. )
  11. type moHeader struct {
  12. MagicNumber uint32
  13. MajorVersion uint16
  14. MinorVersion uint16
  15. MsgIdCount uint32
  16. MsgIdOffset uint32
  17. MsgStrOffset uint32
  18. HashSize uint32
  19. HashOffset uint32
  20. }
  21. type moStrPos struct {
  22. Size uint32 // must keep fields order
  23. Addr uint32
  24. }
  25. func encodeFile(f *File) []byte {
  26. hdr := &moHeader{
  27. MagicNumber: MoMagicLittleEndian,
  28. }
  29. data := encodeData(hdr, f)
  30. data = append(encodeHeader(hdr), data...)
  31. return data
  32. }
  33. // encode data and init moHeader
  34. func encodeData(hdr *moHeader, f *File) []byte {
  35. msgList := []Message{f.MimeHeader.toMessage()}
  36. for _, v := range f.Messages {
  37. if len(v.MsgId) == 0 {
  38. continue
  39. }
  40. if len(v.MsgStr) == 0 && len(v.MsgStrPlural) == 0 {
  41. continue
  42. }
  43. msgList = append(msgList, v)
  44. }
  45. sort.Sort(byMessages(msgList))
  46. var buf bytes.Buffer
  47. var msgIdPosList = make([]moStrPos, len(msgList))
  48. var msgStrPosList = make([]moStrPos, len(msgList))
  49. for i, v := range msgList {
  50. // write msgid
  51. msgId := encodeMsgId(v)
  52. msgIdPosList[i].Addr = uint32(buf.Len() + MoHeaderSize)
  53. msgIdPosList[i].Size = uint32(len(msgId))
  54. buf.WriteString(msgId)
  55. // write msgstr
  56. msgStr := encodeMsgStr(v)
  57. msgStrPosList[i].Addr = uint32(buf.Len() + MoHeaderSize)
  58. msgStrPosList[i].Size = uint32(len(msgStr))
  59. buf.WriteString(msgStr)
  60. }
  61. hdr.MsgIdOffset = uint32(buf.Len() + MoHeaderSize)
  62. binary.Write(&buf, binary.LittleEndian, msgIdPosList)
  63. hdr.MsgStrOffset = uint32(buf.Len() + MoHeaderSize)
  64. binary.Write(&buf, binary.LittleEndian, msgStrPosList)
  65. hdr.MsgIdCount = uint32(len(msgList))
  66. return buf.Bytes()
  67. }
  68. // must called after encodeData
  69. func encodeHeader(hdr *moHeader) []byte {
  70. var buf bytes.Buffer
  71. binary.Write(&buf, binary.LittleEndian, hdr)
  72. return buf.Bytes()
  73. }
  74. func encodeMsgId(v Message) string {
  75. if v.MsgContext != "" && v.MsgIdPlural != "" {
  76. return v.MsgContext + EotSeparator + v.MsgId + NulSeparator + v.MsgIdPlural
  77. }
  78. if v.MsgContext != "" && v.MsgIdPlural == "" {
  79. return v.MsgContext + EotSeparator + v.MsgId
  80. }
  81. if v.MsgContext == "" && v.MsgIdPlural != "" {
  82. return v.MsgId + NulSeparator + v.MsgIdPlural
  83. }
  84. return v.MsgId
  85. }
  86. func encodeMsgStr(v Message) string {
  87. if v.MsgIdPlural != "" {
  88. return strings.Join(v.MsgStrPlural, NulSeparator)
  89. }
  90. return v.MsgStr
  91. }
  92. type byMessages []Message
  93. func (d byMessages) Len() int {
  94. return len(d)
  95. }
  96. func (d byMessages) Less(i, j int) bool {
  97. if a, b := d[i].MsgContext, d[j].MsgContext; a != b {
  98. return a < b
  99. }
  100. if a, b := d[i].MsgId, d[j].MsgId; a != b {
  101. return a < b
  102. }
  103. if a, b := d[i].MsgIdPlural, d[j].MsgIdPlural; a != b {
  104. return a < b
  105. }
  106. return false
  107. }
  108. func (d byMessages) Swap(i, j int) {
  109. d[i], d[j] = d[j], d[i]
  110. }