1 files changed, 46 insertions, 0 deletions
diff --git a/extensions/universalchardet/src/base/CharDistribution.cpp b/extensions/universalchardet/src/base/CharDistribution.cpp
new file mode 100644
index 000000000..7030bd85e
--- /dev/null
+++ b/extensions/universalchardet/src/base/CharDistribution.cpp
@@ -0,0 +1,46 @@
+/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */
+/* This Source Code Form is subject to the terms of the Mozilla Public
+ * License, v. 2.0. If a copy of the MPL was not distributed with this
+ * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
+
+#include "CharDistribution.h"
+
+#include "JISFreq.tab"
+#include "mozilla/ArrayUtils.h"
+
+#define SURE_YES 0.99f
+#define SURE_NO  0.01f
+
+//return confidence base on received data
+float CharDistributionAnalysis::GetConfidence(void)
+{ 
+  //if we didn't receive any character in our consideration range, or the
+  // number of frequent characters is below the minimum threshold, return
+  // negative answer
+  if (mTotalChars <= 0 || mFreqChars <= mDataThreshold)
+    return SURE_NO;
+
+  if (mTotalChars != mFreqChars) {
+    float r = mFreqChars / ((mTotalChars - mFreqChars) * mTypicalDistributionRatio);
+
+    if (r < SURE_YES)
+      return r;
+  }
+  //normalize confidence, (we don't want to be 100% sure)
+  return SURE_YES;
+}
+
+SJISDistributionAnalysis::SJISDistributionAnalysis()
+{
+  mCharToFreqOrder = JISCharToFreqOrder;
+  mTableSize = mozilla::ArrayLength(JISCharToFreqOrder);
+  mTypicalDistributionRatio = JIS_TYPICAL_DISTRIBUTION_RATIO;
+}
+
+EUCJPDistributionAnalysis::EUCJPDistributionAnalysis()
+{
+  mCharToFreqOrder = JISCharToFreqOrder;
+  mTableSize = mozilla::ArrayLength(JISCharToFreqOrder);
+  mTypicalDistributionRatio = JIS_TYPICAL_DISTRIBUTION_RATIO;
+}
+