LatinIME/java/src/com/android/inputmethod/latin/utils/CapsModeUtils.java

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/*
* Copyright (C) 2013 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.InputType;
import android.text.TextUtils;
import com.android.inputmethod.latin.Constants;
import com.android.inputmethod.latin.WordComposer;
import com.android.inputmethod.latin.settings.SpacingAndPunctuations;
import java.util.Locale;
public final class CapsModeUtils {
private CapsModeUtils() {
// This utility class is not publicly instantiable.
}
/**
* Apply an auto-caps mode to a string.
*
* This intentionally does NOT apply manual caps mode. It only changes the capitalization if
* the mode is one of the auto-caps modes.
* @param s The string to capitalize.
* @param capitalizeMode The mode in which to capitalize.
* @param locale The locale for capitalizing.
* @return The capitalized string.
*/
public static String applyAutoCapsMode(final String s, final int capitalizeMode,
final Locale locale) {
if (WordComposer.CAPS_MODE_AUTO_SHIFT_LOCKED == capitalizeMode) {
return s.toUpperCase(locale);
} else if (WordComposer.CAPS_MODE_AUTO_SHIFTED == capitalizeMode) {
return StringUtils.capitalizeFirstCodePoint(s, locale);
} else {
return s;
}
}
/**
* Return whether a constant represents an auto-caps mode (either auto-shift or auto-shift-lock)
* @param mode The mode to test for
* @return true if this represents an auto-caps mode, false otherwise
*/
public static boolean isAutoCapsMode(final int mode) {
return WordComposer.CAPS_MODE_AUTO_SHIFTED == mode
|| WordComposer.CAPS_MODE_AUTO_SHIFT_LOCKED == mode;
}
/**
* Helper method to find out if a code point is starting punctuation.
*
* This include the Unicode START_PUNCTUATION category, but also some other symbols that are
* starting, like the inverted question mark or the double quote.
*
* @param codePoint the code point
* @return true if it's starting punctuation, false otherwise.
*/
private static boolean isStartPunctuation(final int codePoint) {
return (codePoint == Constants.CODE_DOUBLE_QUOTE || codePoint == Constants.CODE_SINGLE_QUOTE
|| codePoint == Constants.CODE_INVERTED_QUESTION_MARK
|| codePoint == Constants.CODE_INVERTED_EXCLAMATION_MARK
|| Character.getType(codePoint) == Character.START_PUNCTUATION);
}
/**
* Determine what caps mode should be in effect at the current offset in
* the text. Only the mode bits set in <var>reqModes</var> will be
* checked. Note that the caps mode flags here are explicitly defined
* to match those in {@link InputType}.
*
* This code is a straight copy of TextUtils.getCapsMode (modulo namespace and formatting
* issues). This will change in the future as we simplify the code for our use and fix bugs.
*
* @param cs The text that should be checked for caps modes.
* @param reqModes The modes to be checked: may be any combination of
* {@link TextUtils#CAP_MODE_CHARACTERS}, {@link TextUtils#CAP_MODE_WORDS}, and
* {@link TextUtils#CAP_MODE_SENTENCES}.
* @param spacingAndPunctuations The current spacing and punctuations settings.
* @param hasSpaceBefore Whether we should consider there is a space inserted at the end of cs
*
* @return Returns the actual capitalization modes that can be in effect
* at the current position, which is any combination of
* {@link TextUtils#CAP_MODE_CHARACTERS}, {@link TextUtils#CAP_MODE_WORDS}, and
* {@link TextUtils#CAP_MODE_SENTENCES}.
*/
public static int getCapsMode(final CharSequence cs, final int reqModes,
final SpacingAndPunctuations spacingAndPunctuations, final boolean hasSpaceBefore) {
// Quick description of what we want to do:
// CAP_MODE_CHARACTERS is always on.
// CAP_MODE_WORDS is on if there is some whitespace before the cursor.
// CAP_MODE_SENTENCES is on if there is some whitespace before the cursor, and the end
// of a sentence just before that.
// We ignore opening parentheses and the like just before the cursor for purposes of
// finding whitespace for WORDS and SENTENCES modes.
// The end of a sentence ends with a period, question mark or exclamation mark. If it's
// a period, it also needs not to be an abbreviation, which means it also needs to either
// be immediately preceded by punctuation, or by a string of only letters with single
// periods interleaved.
// Step 1 : check for cap MODE_CHARACTERS. If it's looked for, it's always on.
if ((reqModes & (TextUtils.CAP_MODE_WORDS | TextUtils.CAP_MODE_SENTENCES)) == 0) {
// Here we are not looking for MODE_WORDS or MODE_SENTENCES, so since we already
// evaluated MODE_CHARACTERS, we can return.
return TextUtils.CAP_MODE_CHARACTERS & reqModes;
}
// Step 2 : Skip (ignore at the end of input) any opening punctuation. This includes
// opening parentheses, brackets, opening quotes, everything that *opens* a span of
// text in the linguistic sense. In RTL languages, this is still an opening sign, although
// it may look like a right parenthesis for example. We also include double quote and
// single quote since they aren't start punctuation in the unicode sense, but should still
// be skipped for English. TODO: does this depend on the language?
int i;
if (hasSpaceBefore) {
i = cs.length() + 1;
} else {
for (i = cs.length(); i > 0; i--) {
final char c = cs.charAt(i - 1);
if (!isStartPunctuation(c)) {
break;
}
}
}
// We are now on the character that precedes any starting punctuation, so in the most
// frequent case this will be whitespace or a letter, although it may occasionally be a
// start of line, or some symbol.
// Step 3 : Search for the start of a paragraph. From the starting point computed in step 2,
// we go back over any space or tab char sitting there. We find the start of a paragraph
// if the first char that's not a space or tab is a start of line (as in \n, start of text,
// or some other similar characters).
int j = i;
char prevChar = Constants.CODE_SPACE;
if (hasSpaceBefore) --j;
while (j > 0) {
prevChar = cs.charAt(j - 1);
if (!Character.isSpaceChar(prevChar) && prevChar != Constants.CODE_TAB) break;
j--;
}
if (j <= 0 || Character.isWhitespace(prevChar)) {
if (spacingAndPunctuations.mUsesGermanRules) {
// In German typography rules, there is a specific case that the first character
// of a new line should not be capitalized if the previous line ends in a comma.
boolean hasNewLine = false;
while (--j >= 0 && Character.isWhitespace(prevChar)) {
if (Constants.CODE_ENTER == prevChar) {
hasNewLine = true;
}
prevChar = cs.charAt(j);
}
if (Constants.CODE_COMMA == prevChar && hasNewLine) {
return (TextUtils.CAP_MODE_CHARACTERS | TextUtils.CAP_MODE_WORDS) & reqModes;
}
}
// There are only spacing chars between the start of the paragraph and the cursor,
// defined as a isWhitespace() char that is neither a isSpaceChar() nor a tab. Both
// MODE_WORDS and MODE_SENTENCES should be active.
return (TextUtils.CAP_MODE_CHARACTERS | TextUtils.CAP_MODE_WORDS
| TextUtils.CAP_MODE_SENTENCES) & reqModes;
}
if (i == j) {
// If we don't have whitespace before index i, it means neither MODE_WORDS
// nor mode sentences should be on so we can return right away.
return TextUtils.CAP_MODE_CHARACTERS & reqModes;
}
if ((reqModes & TextUtils.CAP_MODE_SENTENCES) == 0) {
// Here we know we have whitespace before the cursor (if not, we returned in the above
// if i == j clause), so we need MODE_WORDS to be on. And we don't need to evaluate
// MODE_SENTENCES so we can return right away.
return (TextUtils.CAP_MODE_CHARACTERS | TextUtils.CAP_MODE_WORDS) & reqModes;
}
// Please note that because of the reqModes & CAP_MODE_SENTENCES test a few lines above,
// we know that MODE_SENTENCES is being requested.
// Step 4 : Search for MODE_SENTENCES.
// English is a special case in that "American typography" rules, which are the most common
// in English, state that a sentence terminator immediately following a quotation mark
// should be swapped with it and de-duplicated (included in the quotation mark),
// e.g. <<Did he say, "let's go home?">>
// No other language has such a rule as far as I know, instead putting inside the quotation
// mark as the exact thing quoted and handling the surrounding punctuation independently,
// e.g. <<Did he say, "let's go home"?>>
if (spacingAndPunctuations.mUsesAmericanTypography) {
for (; j > 0; j--) {
// Here we look to go over any closing punctuation. This is because in dominant
// variants of English, the final period is placed within double quotes and maybe
// other closing punctuation signs. This is generally not true in other languages.
final char c = cs.charAt(j - 1);
if (c != Constants.CODE_DOUBLE_QUOTE && c != Constants.CODE_SINGLE_QUOTE
&& Character.getType(c) != Character.END_PUNCTUATION) {
break;
}
}
}
if (j <= 0) return TextUtils.CAP_MODE_CHARACTERS & reqModes;
char c = cs.charAt(--j);
// We found the next interesting chunk of text ; next we need to determine if it's the
// end of a sentence. If we have a sentence terminator (typically a question mark or an
// exclamation mark), then it's the end of a sentence; however, we treat the abbreviation
// marker specially because usually is the same char as the sentence separator (the
// period in most languages) and in this case we need to apply a heuristic to determine
// in which of these senses it's used.
if (spacingAndPunctuations.isSentenceTerminator(c)
&& !spacingAndPunctuations.isAbbreviationMarker(c)) {
return (TextUtils.CAP_MODE_CHARACTERS | TextUtils.CAP_MODE_WORDS
| TextUtils.CAP_MODE_SENTENCES) & reqModes;
}
// If we reach here, we know we have whitespace before the cursor and before that there
// is something that either does not terminate the sentence, or a symbol preceded by the
// start of the text, or it's the sentence separator AND it happens to be the same code
// point as the abbreviation marker.
// If it's a symbol or something that does not terminate the sentence, then we need to
// return caps for MODE_CHARACTERS and MODE_WORDS, but not for MODE_SENTENCES.
if (!spacingAndPunctuations.isSentenceSeparator(c) || j <= 0) {
return (TextUtils.CAP_MODE_CHARACTERS | TextUtils.CAP_MODE_WORDS) & reqModes;
}
// We found out that we have a period. We need to determine if this is a full stop or
// otherwise sentence-ending period, or an abbreviation like "e.g.". An abbreviation
// looks like (\w\.){2,}. Moreover, in German, you put periods after digits for dates
// and some other things, and in German specifically we need to not go into autocaps after
// a whitespace-digits-period sequence.
// To find out, we will have a simple state machine with the following states :
// START, WORD, PERIOD, ABBREVIATION, NUMBER
// On START : (just before the first period)
// letter => WORD
// digit => NUMBER if German; end with caps otherwise
// whitespace => end with no caps (it was a stand-alone period)
// otherwise => end with caps (several periods/symbols in a row)
// On WORD : (within the word just before the first period)
// letter => WORD
// period => PERIOD
// otherwise => end with caps (it was a word with a full stop at the end)
// On PERIOD : (period within a potential abbreviation)
// letter => LETTER
// otherwise => end with caps (it was not an abbreviation)
// On LETTER : (letter within a potential abbreviation)
// letter => LETTER
// period => PERIOD
// otherwise => end with no caps (it was an abbreviation)
// On NUMBER : (period immediately preceded by one or more digits)
// digit => NUMBER
// letter => LETTER (promote to word)
// otherwise => end with no caps (it was a whitespace-digits-period sequence,
// or a punctuation-digits-period sequence like "11.11.")
// "Not an abbreviation" in the above chart essentially covers cases like "...yes.". This
// should capitalize.
final int START = 0;
final int WORD = 1;
final int PERIOD = 2;
final int LETTER = 3;
final int NUMBER = 4;
final int caps = (TextUtils.CAP_MODE_CHARACTERS | TextUtils.CAP_MODE_WORDS
| TextUtils.CAP_MODE_SENTENCES) & reqModes;
final int noCaps = (TextUtils.CAP_MODE_CHARACTERS | TextUtils.CAP_MODE_WORDS) & reqModes;
int state = START;
while (j > 0) {
c = cs.charAt(--j);
switch (state) {
case START:
if (Character.isLetter(c)) {
state = WORD;
} else if (Character.isWhitespace(c)) {
return noCaps;
} else if (Character.isDigit(c) && spacingAndPunctuations.mUsesGermanRules) {
state = NUMBER;
} else {
return caps;
}
break;
case WORD:
if (Character.isLetter(c)) {
state = WORD;
} else if (spacingAndPunctuations.isSentenceSeparator(c)) {
state = PERIOD;
} else {
return caps;
}
break;
case PERIOD:
if (Character.isLetter(c)) {
state = LETTER;
} else {
return caps;
}
break;
case LETTER:
if (Character.isLetter(c)) {
state = LETTER;
} else if (spacingAndPunctuations.isSentenceSeparator(c)) {
state = PERIOD;
} else {
return noCaps;
}
break;
case NUMBER:
if (Character.isLetter(c)) {
state = WORD;
} else if (Character.isDigit(c)) {
state = NUMBER;
} else {
return noCaps;
}
}
}
// Here we arrived at the start of the line. This should behave exactly like whitespace.
return (START == state || LETTER == state) ? noCaps : caps;
}
}