diff options
Diffstat (limited to 'java/src/com/android/inputmethod/latin/CapsModeUtils.java')
| -rw-r--r-- | java/src/com/android/inputmethod/latin/CapsModeUtils.java | 266 |
1 files changed, 266 insertions, 0 deletions
diff --git a/java/src/com/android/inputmethod/latin/CapsModeUtils.java b/java/src/com/android/inputmethod/latin/CapsModeUtils.java new file mode 100644 index 000000000..1012cd519 --- /dev/null +++ b/java/src/com/android/inputmethod/latin/CapsModeUtils.java @@ -0,0 +1,266 @@ +/* + * 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; + +import android.text.InputType; +import android.text.TextUtils; + +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.toTitleCase(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; + } + + /** + * 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 locale The locale to consider for capitalization rules + * @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 Locale locale, + 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 (c != Constants.CODE_DOUBLE_QUOTE && c != Constants.CODE_SINGLE_QUOTE + && Character.getType(c) != Character.START_PUNCTUATION) { + 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)) { + // 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"?>> + // Hence, specifically for English, we treat this special case here. + if (Locale.ENGLISH.getLanguage().equals(locale.getLanguage())) { + 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 question mark or an exclamation mark, it's the end of + // a sentence. If it's neither, the only remaining case is the period so we get the opposite + // case out of the way. + if (c == Constants.CODE_QUESTION_MARK || c == Constants.CODE_EXCLAMATION_MARK) { + return (TextUtils.CAP_MODE_CHARACTERS | TextUtils.CAP_MODE_SENTENCES) & reqModes; + } + if (c != Constants.CODE_PERIOD || 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,} + // To find out, we will have a simple state machine with the following states : + // START, WORD, PERIOD, ABBREVIATION + // On START : (just before the first period) + // letter => WORD + // 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) + // "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 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 { + return caps; + } + break; + case WORD: + if (Character.isLetter(c)) { + state = WORD; + } else if (c == Constants.CODE_PERIOD) { + 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 (c == Constants.CODE_PERIOD) { + state = PERIOD; + } 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; + } +} |