/extensions/universalchardet/src/base/nsEUCJPProber.cpp

http://github.com/zpao/v8monkey · C++ · 101 lines · 49 code · 12 blank · 40 comment · 11 complexity · 1e69f990405a66ed45b4e8a28fbe8177 MD5 · raw file

  1. /* -*- Mode: C; tab-width: 4; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
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  37. // for japanese encoding, obeserve characteristic:
  38. // 1, kana character (or hankaku?) often have hight frequency of appereance
  39. // 2, kana character often exist in group
  40. // 3, certain combination of kana is never used in japanese language
  41. #include "nsEUCJPProber.h"
  42. #include "nsDebug.h"
  43. void nsEUCJPProber::Reset(void)
  44. {
  45. mCodingSM->Reset();
  46. mState = eDetecting;
  47. mContextAnalyser.Reset(mIsPreferredLanguage);
  48. mDistributionAnalyser.Reset(mIsPreferredLanguage);
  49. }
  50. nsProbingState nsEUCJPProber::HandleData(const char* aBuf, PRUint32 aLen)
  51. {
  52. NS_ASSERTION(aLen, "HandleData called with empty buffer");
  53. nsSMState codingState;
  54. for (PRUint32 i = 0; i < aLen; i++)
  55. {
  56. codingState = mCodingSM->NextState(aBuf[i]);
  57. if (codingState == eItsMe)
  58. {
  59. mState = eFoundIt;
  60. break;
  61. }
  62. if (codingState == eStart)
  63. {
  64. PRUint32 charLen = mCodingSM->GetCurrentCharLen();
  65. if (i == 0)
  66. {
  67. mLastChar[1] = aBuf[0];
  68. mContextAnalyser.HandleOneChar(mLastChar, charLen);
  69. mDistributionAnalyser.HandleOneChar(mLastChar, charLen);
  70. }
  71. else
  72. {
  73. mContextAnalyser.HandleOneChar(aBuf+i-1, charLen);
  74. mDistributionAnalyser.HandleOneChar(aBuf+i-1, charLen);
  75. }
  76. }
  77. }
  78. mLastChar[0] = aBuf[aLen-1];
  79. if (mState == eDetecting)
  80. if (mContextAnalyser.GotEnoughData() && GetConfidence() > SHORTCUT_THRESHOLD)
  81. mState = eFoundIt;
  82. return mState;
  83. }
  84. float nsEUCJPProber::GetConfidence(void)
  85. {
  86. float contxtCf = mContextAnalyser.GetConfidence();
  87. float distribCf = mDistributionAnalyser.GetConfidence();
  88. return (contxtCf > distribCf ? contxtCf : distribCf);
  89. }