1 files changed, 200 insertions, 0 deletions
diff --git a/intl/icu/source/i18n/csrucode.cpp b/intl/icu/source/i18n/csrucode.cpp
new file mode 100644
index 0000000000..a6e6f83f0f
--- /dev/null
+++ b/intl/icu/source/i18n/csrucode.cpp
@@ -0,0 +1,200 @@
+// © 2016 and later: Unicode, Inc. and others.
+// License & terms of use: http://www.unicode.org/copyright.html
+/*
+ **********************************************************************
+ *   Copyright (C) 2005-2013, International Business Machines
+ *   Corporation and others.  All Rights Reserved.
+ **********************************************************************
+ */
+
+#include "unicode/utypes.h"
+
+#if !UCONFIG_NO_CONVERSION
+
+#include "csrucode.h"
+#include "csmatch.h"
+
+U_NAMESPACE_BEGIN
+
+CharsetRecog_Unicode::~CharsetRecog_Unicode()
+{
+    // nothing to do
+}
+
+CharsetRecog_UTF_16_BE::~CharsetRecog_UTF_16_BE()
+{
+    // nothing to do
+}
+
+const char *CharsetRecog_UTF_16_BE::getName() const
+{
+    return "UTF-16BE";
+}
+
+// UTF-16 confidence calculation. Very simple minded, but better than nothing.
+//   Any 8 bit non-control characters bump the confidence up. These have a zero high byte,
+//     and are very likely to be UTF-16, although they could also be part of a UTF-32 code.
+//   NULs are a contra-indication, they will appear commonly if the actual encoding is UTF-32.
+//   NULs should be rare in actual text. 
+
+static int32_t adjustConfidence(char16_t codeUnit, int32_t confidence) {
+    if (codeUnit == 0) {
+        confidence -= 10;
+    } else if ((codeUnit >= 0x20 && codeUnit <= 0xff) || codeUnit == 0x0a) {
+        confidence += 10;
+    }
+    if (confidence < 0) {
+        confidence = 0;
+    } else if (confidence > 100) {
+        confidence = 100;
+    }
+    return confidence;
+}
+
+
+UBool CharsetRecog_UTF_16_BE::match(InputText* textIn, CharsetMatch *results) const
+{
+    const uint8_t *input = textIn->fRawInput;
+    int32_t confidence = 10;
+    int32_t length = textIn->fRawLength;
+
+    int32_t bytesToCheck = (length > 30) ? 30 : length;
+    for (int32_t charIndex=0; charIndex<bytesToCheck-1; charIndex+=2) {
+        char16_t codeUnit = (input[charIndex] << 8) | input[charIndex + 1];
+        if (charIndex == 0 && codeUnit == 0xFEFF) {
+            confidence = 100;
+            break;
+        }
+        confidence = adjustConfidence(codeUnit, confidence);
+        if (confidence == 0 || confidence == 100) {
+            break;
+        }
+    }
+    if (bytesToCheck < 4 && confidence < 100) {
+        confidence = 0;
+    }
+    results->set(textIn, this, confidence);
+    return (confidence > 0);
+}
+
+CharsetRecog_UTF_16_LE::~CharsetRecog_UTF_16_LE()
+{
+    // nothing to do
+}
+
+const char *CharsetRecog_UTF_16_LE::getName() const
+{
+    return "UTF-16LE";
+}
+
+UBool CharsetRecog_UTF_16_LE::match(InputText* textIn, CharsetMatch *results) const
+{
+    const uint8_t *input = textIn->fRawInput;
+    int32_t confidence = 10;
+    int32_t length = textIn->fRawLength;
+
+    int32_t bytesToCheck = (length > 30) ? 30 : length;
+    for (int32_t charIndex=0; charIndex<bytesToCheck-1; charIndex+=2) {
+        char16_t codeUnit = input[charIndex] | (input[charIndex + 1] << 8);
+        if (charIndex == 0 && codeUnit == 0xFEFF) {
+            confidence = 100;     // UTF-16 BOM
+            if (length >= 4 && input[2] == 0 && input[3] == 0) {
+                confidence = 0;   // UTF-32 BOM
+            }
+            break;
+        }
+        confidence = adjustConfidence(codeUnit, confidence);
+        if (confidence == 0 || confidence == 100) {
+            break;
+        }
+    }
+    if (bytesToCheck < 4 && confidence < 100) {
+        confidence = 0;
+    }
+    results->set(textIn, this, confidence);
+    return (confidence > 0);
+}
+
+CharsetRecog_UTF_32::~CharsetRecog_UTF_32()
+{
+    // nothing to do
+}
+
+UBool CharsetRecog_UTF_32::match(InputText* textIn, CharsetMatch *results) const
+{
+    const uint8_t *input = textIn->fRawInput;
+    int32_t limit = (textIn->fRawLength / 4) * 4;
+    int32_t numValid = 0;
+    int32_t numInvalid = 0;
+    bool hasBOM = false;
+    int32_t confidence = 0;
+
+    if (limit > 0 && getChar(input, 0) == 0x0000FEFFUL) {
+        hasBOM = true;
+    }
+
+    for(int32_t i = 0; i < limit; i += 4) {
+        int32_t ch = getChar(input, i);
+
+        if (ch < 0 || ch >= 0x10FFFF || (ch >= 0xD800 && ch <= 0xDFFF)) {
+            numInvalid += 1;
+        } else {
+            numValid += 1;
+        }
+    }
+
+
+    // Cook up some sort of confidence score, based on presence of a BOM
+    //    and the existence of valid and/or invalid multi-byte sequences.
+    if (hasBOM && numInvalid==0) {
+        confidence = 100;
+    } else if (hasBOM && numValid > numInvalid*10) {
+        confidence = 80;
+    } else if (numValid > 3 && numInvalid == 0) {
+        confidence = 100;            
+    } else if (numValid > 0 && numInvalid == 0) {
+        confidence = 80;
+    } else if (numValid > numInvalid*10) {
+        // Probably corrupt UTF-32BE data.  Valid sequences aren't likely by chance.
+        confidence = 25;
+    }
+
+    results->set(textIn, this, confidence);
+    return (confidence > 0);
+}
+
+CharsetRecog_UTF_32_BE::~CharsetRecog_UTF_32_BE()
+{
+    // nothing to do
+}
+
+const char *CharsetRecog_UTF_32_BE::getName() const
+{
+    return "UTF-32BE";
+}
+
+int32_t CharsetRecog_UTF_32_BE::getChar(const uint8_t *input, int32_t index) const
+{
+    return input[index + 0] << 24 | input[index + 1] << 16 |
+           input[index + 2] <<  8 | input[index + 3];
+} 
+
+CharsetRecog_UTF_32_LE::~CharsetRecog_UTF_32_LE()
+{
+    // nothing to do
+}
+
+const char *CharsetRecog_UTF_32_LE::getName() const
+{
+    return "UTF-32LE";
+}
+
+int32_t CharsetRecog_UTF_32_LE::getChar(const uint8_t *input, int32_t index) const
+{
+    return input[index + 3] << 24 | input[index + 2] << 16 |
+           input[index + 1] <<  8 | input[index + 0];
+}
+
+U_NAMESPACE_END
+#endif
+