Move util classes to the latin/utils directory

Change-Id: I1c5b27c8edf231680edb8d96f63b9d04cfc6a6fa

1 files changed, 319 insertions, 0 deletions

diff --git a/java/src/com/android/inputmethod/latin/utils/StringUtils.java b/java/src/com/android/inputmethod/latin/utils/StringUtils.java
new file mode 100644
index 000000000..7406d855a
--- /dev/null
+++ b/java/src/com/android/inputmethod/latin/utils/StringUtils.java
@@ -0,0 +1,319 @@
+/*
+ * Copyright (C) 2012 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.
+ */
+
+package com.android.inputmethod.latin.utils;
+
+import android.text.TextUtils;
+
+import com.android.inputmethod.latin.Constants;
+
+import java.util.ArrayList;
+import java.util.Locale;
+
+public final class StringUtils {
+    public static final int CAPITALIZE_NONE = 0;  // No caps, or mixed case
+    public static final int CAPITALIZE_FIRST = 1; // First only
+    public static final int CAPITALIZE_ALL = 2;   // All caps
+
+    private StringUtils() {
+        // This utility class is not publicly instantiable.
+    }
+
+    public static int codePointCount(final String text) {
+        if (TextUtils.isEmpty(text)) return 0;
+        return text.codePointCount(0, text.length());
+    }
+
+    public static boolean containsInArray(final String text, final String[] array) {
+        for (final String element : array) {
+            if (text.equals(element)) return true;
+        }
+        return false;
+    }
+
+    /**
+     * Comma-Splittable Text is similar to Comma-Separated Values (CSV) but has much simpler syntax.
+     * Unlike CSV, Comma-Splittable Text has no escaping mechanism, so that the text can't contain
+     * a comma character in it.
+     */
+    private static final String SEPARATOR_FOR_COMMA_SPLITTABLE_TEXT = ",";
+
+    public static boolean containsInCommaSplittableText(final String text,
+            final String extraValues) {
+        if (TextUtils.isEmpty(extraValues)) {
+            return false;
+        }
+        return containsInArray(text, extraValues.split(SEPARATOR_FOR_COMMA_SPLITTABLE_TEXT));
+    }
+
+    public static String appendToCommaSplittableTextIfNotExists(final String text,
+            final String extraValues) {
+        if (TextUtils.isEmpty(extraValues)) {
+            return text;
+        }
+        if (containsInCommaSplittableText(text, extraValues)) {
+            return extraValues;
+        }
+        return extraValues + SEPARATOR_FOR_COMMA_SPLITTABLE_TEXT + text;
+    }
+
+    public static String removeFromCommaSplittableTextIfExists(final String text,
+            final String extraValues) {
+        if (TextUtils.isEmpty(extraValues)) {
+            return "";
+        }
+        final String[] elements = extraValues.split(SEPARATOR_FOR_COMMA_SPLITTABLE_TEXT);
+        if (!containsInArray(text, elements)) {
+            return extraValues;
+        }
+        final ArrayList<String> result = CollectionUtils.newArrayList(elements.length - 1);
+        for (final String element : elements) {
+            if (!text.equals(element)) {
+                result.add(element);
+            }
+        }
+        return TextUtils.join(SEPARATOR_FOR_COMMA_SPLITTABLE_TEXT, result);
+    }
+
+    /**
+     * Remove duplicates from an array of strings.
+     *
+     * This method will always keep the first occurrence of all strings at their position
+     * in the array, removing the subsequent ones.
+     */
+    public static void removeDupes(final ArrayList<String> suggestions) {
+        if (suggestions.size() < 2) return;
+        int i = 1;
+        // Don't cache suggestions.size(), since we may be removing items
+        while (i < suggestions.size()) {
+            final String cur = suggestions.get(i);
+            // Compare each suggestion with each previous suggestion
+            for (int j = 0; j < i; j++) {
+                final String previous = suggestions.get(j);
+                if (TextUtils.equals(cur, previous)) {
+                    suggestions.remove(i);
+                    i--;
+                    break;
+                }
+            }
+            i++;
+        }
+    }
+
+    public static String capitalizeFirstCodePoint(final String s, final Locale locale) {
+        if (s.length() <= 1) {
+            return s.toUpperCase(locale);
+        }
+        // Please refer to the comment below in
+        // {@link #capitalizeFirstAndDowncaseRest(String,Locale)} as this has the same shortcomings
+        final int cutoff = s.offsetByCodePoints(0, 1);
+        return s.substring(0, cutoff).toUpperCase(locale) + s.substring(cutoff);
+    }
+
+    public static String capitalizeFirstAndDowncaseRest(final String s, final Locale locale) {
+        if (s.length() <= 1) {
+            return s.toUpperCase(locale);
+        }
+        // TODO: fix the bugs below
+        // - This does not work for Greek, because it returns upper case instead of title case.
+        // - It does not work for Serbian, because it fails to account for the "lj" character,
+        // which should be "Lj" in title case and "LJ" in upper case.
+        // - It does not work for Dutch, because it fails to account for the "ij" digraph when it's
+        // written as two separate code points. They are two different characters but both should
+        // be capitalized as "IJ" as if they were a single letter in most words (not all). If the
+        // unicode char for the ligature is used however, it works.
+        final int cutoff = s.offsetByCodePoints(0, 1);
+        return s.substring(0, cutoff).toUpperCase(locale) + s.substring(cutoff).toLowerCase(locale);
+    }
+
+    private static final int[] EMPTY_CODEPOINTS = {};
+
+    public static int[] toCodePointArray(final String string) {
+        final int length = string.length();
+        if (length <= 0) {
+            return EMPTY_CODEPOINTS;
+        }
+        final int[] codePoints = new int[string.codePointCount(0, length)];
+        int destIndex = 0;
+        for (int index = 0; index < length; index = string.offsetByCodePoints(index, 1)) {
+            codePoints[destIndex] = string.codePointAt(index);
+            destIndex++;
+        }
+        return codePoints;
+    }
+
+    // This method assumes the text is not null. For the empty string, it returns CAPITALIZE_NONE.
+    public static int getCapitalizationType(final String text) {
+        // If the first char is not uppercase, then the word is either all lower case or
+        // camel case, and in either case we return CAPITALIZE_NONE.
+        final int len = text.length();
+        int index = 0;
+        for (; index < len; index = text.offsetByCodePoints(index, 1)) {
+            if (Character.isLetter(text.codePointAt(index))) {
+                break;
+            }
+        }
+        if (index == len) return CAPITALIZE_NONE;
+        if (!Character.isUpperCase(text.codePointAt(index))) {
+            return CAPITALIZE_NONE;
+        }
+        int capsCount = 1;
+        int letterCount = 1;
+        for (index = text.offsetByCodePoints(index, 1); index < len;
+                index = text.offsetByCodePoints(index, 1)) {
+            if (1 != capsCount && letterCount != capsCount) break;
+            final int codePoint = text.codePointAt(index);
+            if (Character.isUpperCase(codePoint)) {
+                ++capsCount;
+                ++letterCount;
+            } else if (Character.isLetter(codePoint)) {
+                // We need to discount non-letters since they may not be upper-case, but may
+                // still be part of a word (e.g. single quote or dash, as in "IT'S" or "FULL-TIME")
+                ++letterCount;
+            }
+        }
+        // We know the first char is upper case. So we want to test if either every letter other
+        // than the first is lower case, or if they are all upper case. If the string is exactly
+        // one char long, then we will arrive here with letterCount 1, and this is correct, too.
+        if (1 == capsCount) return CAPITALIZE_FIRST;
+        return (letterCount == capsCount ? CAPITALIZE_ALL : CAPITALIZE_NONE);
+    }
+
+    public static boolean isIdenticalAfterUpcase(final String text) {
+        final int len = text.length();
+        for (int i = 0; i < len; i = text.offsetByCodePoints(i, 1)) {
+            final int codePoint = text.codePointAt(i);
+            if (Character.isLetter(codePoint) && !Character.isUpperCase(codePoint)) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    public static boolean isIdenticalAfterDowncase(final String text) {
+        final int len = text.length();
+        for (int i = 0; i < len; i = text.offsetByCodePoints(i, 1)) {
+            final int codePoint = text.codePointAt(i);
+            if (Character.isLetter(codePoint) && !Character.isLowerCase(codePoint)) {
+                return false;
+            }
+        }
+        return true;
+    }
+
+    public static boolean isIdenticalAfterCapitalizeEachWord(final String text,
+            final String separators) {
+        boolean needCapsNext = true;
+        final int len = text.length();
+        for (int i = 0; i < len; i = text.offsetByCodePoints(i, 1)) {
+            final int codePoint = text.codePointAt(i);
+            if (Character.isLetter(codePoint)) {
+                if ((needCapsNext && !Character.isUpperCase(codePoint))
+                        || (!needCapsNext && !Character.isLowerCase(codePoint))) {
+                    return false;
+                }
+            }
+            // We need a capital letter next if this is a separator.
+            needCapsNext = (-1 != separators.indexOf(codePoint));
+        }
+        return true;
+    }
+
+    // TODO: like capitalizeFirst*, this does not work perfectly for Dutch because of the IJ digraph
+    // which should be capitalized together in *some* cases.
+    public static String capitalizeEachWord(final String text, final String separators,
+            final Locale locale) {
+        final StringBuilder builder = new StringBuilder();
+        boolean needCapsNext = true;
+        final int len = text.length();
+        for (int i = 0; i < len; i = text.offsetByCodePoints(i, 1)) {
+            final String nextChar = text.substring(i, text.offsetByCodePoints(i, 1));
+            if (needCapsNext) {
+                builder.append(nextChar.toUpperCase(locale));
+            } else {
+                builder.append(nextChar.toLowerCase(locale));
+            }
+            // We need a capital letter next if this is a separator.
+            needCapsNext = (-1 != separators.indexOf(nextChar.codePointAt(0)));
+        }
+        return builder.toString();
+    }
+
+    /**
+     * Approximates whether the text before the cursor looks like a URL.
+     *
+     * This is not foolproof, but it should work well in the practice.
+     * Essentially it walks backward from the cursor until it finds something that's not a letter,
+     * digit, or common URL symbol like underscore. If it hasn't found a period yet, then it
+     * does not look like a URL.
+     * If the text:
+     * - starts with www and contains a period
+     * - starts with a slash preceded by either a slash, whitespace, or start-of-string
+     * Then it looks like a URL and we return true. Otherwise, we return false.
+     *
+     * Note: this method is called quite often, and should be fast.
+     *
+     * TODO: This will return that "abc./def" and ".abc/def" look like URLs to keep down the
+     * code complexity, but ideally it should not. It's acceptable for now.
+     */
+    public static boolean lastPartLooksLikeURL(final CharSequence text) {
+        int i = text.length();
+        if (0 == i) return false;
+        int wCount = 0;
+        int slashCount = 0;
+        boolean hasSlash = false;
+        boolean hasPeriod = false;
+        int codePoint = 0;
+        while (i > 0) {
+            codePoint =  Character.codePointBefore(text, i);
+            if (codePoint < Constants.CODE_PERIOD || codePoint > 'z') {
+                // Handwavy heuristic to see if that's a URL character. Anything between period
+                // and z. This includes all lower- and upper-case ascii letters, period,
+                // underscore, arrobase, question mark, equal sign. It excludes spaces, exclamation
+                // marks, double quotes...
+                // Anything that's not a URL-like character causes us to break from here and
+                // evaluate normally.
+                break;
+            }
+            if (Constants.CODE_PERIOD == codePoint) {
+                hasPeriod = true;
+            }
+            if (Constants.CODE_SLASH == codePoint) {
+                hasSlash = true;
+                if (2 == ++slashCount) {
+                    return true;
+                }
+            } else {
+                slashCount = 0;
+            }
+            if ('w' == codePoint) {
+                ++wCount;
+            } else {
+                wCount = 0;
+            }
+            i = Character.offsetByCodePoints(text, i, -1);
+        }
+        // End of the text run.
+        // If it starts with www and includes a period, then it looks like a URL.
+        if (wCount >= 3 && hasPeriod) return true;
+        // If it starts with a slash, and the code point before is whitespace, it looks like an URL.
+        if (1 == slashCount && (0 == i || Character.isWhitespace(codePoint))) return true;
+        // If it has both a period and a slash, it looks like an URL.
+        if (hasPeriod && hasSlash) return true;
+        // Otherwise, it doesn't look like an URL.
+        return false;
+    }
+}