Add spellcheck and word suggestion to the prediction service

third_party/android_prediction/utils/char_utils.h

+/*
+ * Copyright (C) 2010 The Android Open Source Project
+ *
+ * Licensed under the Apache License, Version 2.0 (the "License");
+ * you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *      http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS,
+ * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
+ * See the License for the specific language governing permissions and
+ * limitations under the License.
+ */
+
+#ifndef LATINIME_CHAR_UTILS_H
+#define LATINIME_CHAR_UTILS_H
+
+#include <cctype>
+#include <cstring>
+#include <vector>
+
+#include "third_party/android_prediction/defines.h"
+
+namespace latinime {
+
+class CharUtils {
+ public:
+    static AK_FORCE_INLINE bool isAsciiUpper(int c) {
+        // Note: isupper(...) reports false positives for some Cyrillic characters, causing them to
+        // be incorrectly lower-cased using toAsciiLower(...) rather than latin_tolower(...).
+        return (c >= 'A' && c <= 'Z');
+    }
+
+    static AK_FORCE_INLINE int toAsciiLower(int c) {
+        return c - 'A' + 'a';
+    }
+
+    static AK_FORCE_INLINE bool isAscii(int c) {
+        return isascii(c) != 0;
+    }
+
+    static AK_FORCE_INLINE int toLowerCase(const int c) {
+        if (isAsciiUpper(c)) {
+            return toAsciiLower(c);
+        }
+        if (isAscii(c)) {
+            return c;
+        }
+        return static_cast<int>(latin_tolower(static_cast<unsigned short>(c)));
+    }
+
+    static AK_FORCE_INLINE int toBaseLowerCase(const int c) {
+        return toLowerCase(toBaseCodePoint(c));
+    }
+
+    static AK_FORCE_INLINE bool isIntentionalOmissionCodePoint(const int codePoint) {
+        // TODO: Do not hardcode here
+        return codePoint == KEYCODE_SINGLE_QUOTE || codePoint == KEYCODE_HYPHEN_MINUS;
+    }
+
+    static AK_FORCE_INLINE int getCodePointCount(const int arraySize, const int *const codePoints) {
+        int size = 0;
+        for (; size < arraySize; ++size) {
+            if (codePoints[size] == '\0') {
+                break;
+            }
+        }
+        return size;
+    }
+
+    static AK_FORCE_INLINE int toBaseCodePoint(int c) {
+        if (c < BASE_CHARS_SIZE) {
+            return static_cast<int>(BASE_CHARS[c]);
+        }
+        return c;
+    }
+
+    static AK_FORCE_INLINE int getSpaceCount(const int *const codePointBuffer, const int length) {
+        int spaceCount = 0;
+        for (int i = 0; i < length; ++i) {
+            if (codePointBuffer[i] == KEYCODE_SPACE) {
+                ++spaceCount;
+            }
+        }
+        return spaceCount;
+    }
+
+    static AK_FORCE_INLINE int isInUnicodeSpace(const int codePoint) {
+        return codePoint >= MIN_UNICODE_CODE_POINT && codePoint <= MAX_UNICODE_CODE_POINT;
+    }
+
+    static unsigned short latin_tolower(const unsigned short c);
+    static const std::vector<int> EMPTY_STRING;
+
+    // Returns updated code point count. Returns 0 when the code points cannot be marked as a
+    // Beginning-of-Sentence.
+    static AK_FORCE_INLINE int attachBeginningOfSentenceMarker(int *const codePoints,
+            const int codePointCount, const int maxCodePoint) {
+        if (codePointCount > 0 && codePoints[0] == CODE_POINT_BEGINNING_OF_SENTENCE) {
+            // Marker has already been attached.
+            return codePointCount;
+        }
+        if (codePointCount >= maxCodePoint) {
+            // the code points cannot be marked as a Beginning-of-Sentence.
+            return 0;
+        }
+        memmove(codePoints + 1, codePoints, sizeof(int) * codePointCount);
+        codePoints[0] = CODE_POINT_BEGINNING_OF_SENTENCE;
+        return codePointCount + 1;
+    }
+
+ private:
+    DISALLOW_IMPLICIT_CONSTRUCTORS(CharUtils);
+
+    static const int MIN_UNICODE_CODE_POINT;
+    static const int MAX_UNICODE_CODE_POINT;
+
+    /**
+     * Table mapping most combined Latin, Greek, and Cyrillic characters
+     * to their base characters.  If c is in range, BASE_CHARS[c] == c
+     * if c is not a combined character, or the base character if it
+     * is combined.
+     */
+    static const int BASE_CHARS_SIZE = 0x0500;
+    static const unsigned short BASE_CHARS[BASE_CHARS_SIZE];
+};
+} // namespace latinime
+#endif // LATINIME_CHAR_UTILS_H