HeliBoard/app/src/main/java/helium314/keyboard/latin/common/StringUtils.java
2025-03-02 07:28:37 +01:00

546 lines
23 KiB
Java

/*
* Copyright (C) 2012 The Android Open Source Project
* modified
* SPDX-License-Identifier: Apache-2.0 AND GPL-3.0-only
*/
package helium314.keyboard.latin.common;
import androidx.annotation.NonNull;
import androidx.annotation.Nullable;
import helium314.keyboard.keyboard.internal.keyboard_parser.floris.KeyCode;
import helium314.keyboard.latin.utils.ScriptUtils;
import java.util.Arrays;
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 static final char CHAR_LINE_FEED = 0X000A;
private static final char CHAR_VERTICAL_TAB = 0X000B;
private static final char CHAR_FORM_FEED = 0X000C;
private static final char CHAR_CARRIAGE_RETURN = 0X000D;
private static final char CHAR_NEXT_LINE = 0X0085;
private static final char CHAR_LINE_SEPARATOR = 0X2028;
private static final char CHAR_PARAGRAPH_SEPARATOR = 0X2029;
private StringUtils() {
// This utility class is not publicly instantiable.
}
// Taken from android.text.TextUtils. We are extensively using this method in many places,
// some of which don't have the android libraries available.
/**
* Returns true if the string is null or 0-length.
*
* @param str the string to be examined
* @return true if str is null or zero length
*/
public static boolean isEmpty(@Nullable final CharSequence str) {
return (str == null || str.length() == 0);
}
public static int codePointCount(@Nullable final CharSequence text) {
if (isEmpty(text)) {
return 0;
}
return Character.codePointCount(text, 0, text.length());
}
@NonNull
public static String newSingleCodePointString(final int codePoint) {
if (Character.charCount(codePoint) == 1) {
// Optimization: avoid creating a temporary array for characters that are
// represented by a single char value
return String.valueOf((char) codePoint);
}
// For surrogate pair
return new String(Character.toChars(codePoint));
}
@NonNull
public static String capitalizeFirstCodePoint(@NonNull final String s,
@NonNull final Locale locale) {
if (s.length() <= 1) {
return s.toUpperCase(getLocaleUsedForToTitleCase(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(getLocaleUsedForToTitleCase(locale))
+ s.substring(cutoff);
}
@NonNull
public static String capitalizeFirstAndDowncaseRest(@NonNull final String s,
@NonNull final Locale locale) {
if (s.length() <= 1) {
return s.toUpperCase(getLocaleUsedForToTitleCase(locale));
}
// TODO: fix the bugs below
// - 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(getLocaleUsedForToTitleCase(locale))
+ s.substring(cutoff).toLowerCase(locale);
}
@NonNull
public static int[] toCodePointArray(@NonNull final CharSequence charSequence) {
return toCodePointArray(charSequence, 0, charSequence.length());
}
@NonNull
private static final int[] EMPTY_CODEPOINTS = {};
/**
* Converts a range of a string to an array of code points.
*
* @param charSequence the source string.
* @param startIndex the start index inside the string in java chars, inclusive.
* @param endIndex the end index inside the string in java chars, exclusive.
* @return a new array of code points. At most endIndex - startIndex, but possibly less.
*/
@NonNull
public static int[] toCodePointArray(@NonNull final CharSequence charSequence,
final int startIndex, final int endIndex) {
final int length = charSequence.length();
if (length <= 0) {
return EMPTY_CODEPOINTS;
}
final int[] codePoints =
new int[Character.codePointCount(charSequence, startIndex, endIndex)];
copyCodePointsAndReturnCodePointCount(codePoints, charSequence, startIndex, endIndex,
false /* downCase */);
return codePoints;
}
/**
* Copies the codepoints in a CharSequence to an int array.
* <p>
* This method assumes there is enough space in the array to store the code points. The size
* can be measured with Character#codePointCount(CharSequence, int, int) before passing to this
* method. If the int array is too small, an ArrayIndexOutOfBoundsException will be thrown.
* Also, this method makes no effort to be thread-safe. Do not modify the CharSequence while
* this method is running, or the behavior is undefined.
* This method can optionally downcase code points before copying them, but it pays no attention
* to locale while doing so.
*
* @param destination the int array.
* @param charSequence the CharSequence.
* @param startIndex the start index inside the string in java chars, inclusive.
* @param endIndex the end index inside the string in java chars, exclusive.
* @param downCase if this is true, code points will be downcased before being copied.
* @return the number of copied code points.
*/
public static int copyCodePointsAndReturnCodePointCount(@NonNull final int[] destination,
@NonNull final CharSequence charSequence, final int startIndex, final int endIndex,
final boolean downCase) {
int destIndex = 0;
for (int index = startIndex; index < endIndex;
index = Character.offsetByCodePoints(charSequence, index, 1)) {
final int codePoint = Character.codePointAt(charSequence, index);
// TODO: stop using this, as it's not aware of the locale and does not always do
// the right thing.
destination[destIndex] = downCase ? Character.toLowerCase(codePoint) : codePoint;
destIndex++;
}
return destIndex;
}
@NonNull
public static int[] toSortedCodePointArray(@NonNull final String string) {
final int[] codePoints = toCodePointArray(string);
Arrays.sort(codePoints);
return codePoints;
}
/**
* Construct a String from a code point array
*
* @param codePoints a code point array that is null terminated when its logical length is
* shorter than the array length.
* @return a string constructed from the code point array.
*/
@NonNull
public static String getStringFromNullTerminatedCodePointArray(
@NonNull final int[] codePoints) {
int stringLength = codePoints.length;
for (int i = 0; i < codePoints.length; i++) {
if (codePoints[i] == 0) {
stringLength = i;
break;
}
}
return new String(codePoints, 0 /* offset */, stringLength);
}
// This method assumes the text is not null. For the empty string, it returns CAPITALIZE_NONE.
public static int getCapitalizationType(@NonNull 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(@NonNull final String text) {
final int length = text.length();
int i = 0;
while (i < length) {
final int codePoint = text.codePointAt(i);
if (Character.isLetter(codePoint) && !Character.isUpperCase(codePoint)) {
return false;
}
i += Character.charCount(codePoint);
}
return true;
}
public static boolean isIdenticalAfterDowncase(@NonNull final String text) {
final int length = text.length();
int i = 0;
while (i < length) {
final int codePoint = text.codePointAt(i);
if (Character.isLetter(codePoint) && !Character.isLowerCase(codePoint)) {
return false;
}
i += Character.charCount(codePoint);
}
return true;
}
public static boolean isIdenticalAfterCapitalizeEachWord(@NonNull final String text,
@NonNull final int[] sortedSeparators) {
boolean needsCapsNext = 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 ((needsCapsNext && !Character.isUpperCase(codePoint))
|| (!needsCapsNext && !Character.isLowerCase(codePoint))) {
return false;
}
}
// We need a capital letter next if this is a separator.
needsCapsNext = (Arrays.binarySearch(sortedSeparators, codePoint) >= 0);
}
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.
@NonNull
public static String capitalizeEachWord(@NonNull final String text,
@NonNull final int[] sortedSeparators, @NonNull final Locale locale) {
final StringBuilder builder = new StringBuilder();
boolean needsCapsNext = 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 (needsCapsNext) {
builder.append(nextChar.toUpperCase(locale));
} else {
builder.append(nextChar.toLowerCase(locale));
}
// We need a capital letter next if this is a separator.
needsCapsNext = (Arrays.binarySearch(sortedSeparators, nextChar.codePointAt(0)) >= 0);
}
return builder.toString();
}
/**
* Approximates whether the text before the cursor looks like a URL.
* <p>
* 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.
* <p>
* Note: this method is called quite often, and should be fast.
* <p>
* 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(@NonNull 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.
return hasPeriod && hasSlash;
// Otherwise, it doesn't look like an URL.
}
/**
* Examines the string and returns whether we're inside a double quote.
* <p>
* This is used to decide whether we should put an automatic space before or after a double
* quote character. If we're inside a quotation, then we want to close it, so we want a space
* after and not before. Otherwise, we want to open the quotation, so we want a space before
* and not after. Exception: after a digit, we never want a space because the "inch" or
* "minutes" use cases is dominant after digits.
* In the practice, we determine whether we are in a quotation or not by finding the previous
* double quote character, and looking at whether it's followed by whitespace. If so, that
* was a closing quotation mark, so we're not inside a double quote. If it's not followed
* by whitespace, then it was an opening quotation mark, and we're inside a quotation.
* However, on the way to the double quote we can determine, some double quotes might be
* ignored, e.g. because they are followed by punctuation. These double quotes are counted and
* taken into account.
*
* @param text the text to examine.
* @return whether we're inside a double quote.
*/
public static boolean isInsideDoubleQuoteOrAfterDigit(@NonNull final CharSequence text) {
int i = text.length();
if (0 == i) {
return false;
}
int codePoint = Character.codePointBefore(text, i);
if (Character.isDigit(codePoint)) {
return true;
}
int prevCodePoint = 0;
int ignoredDoubleQuoteCount = 0;
while (i > 0) {
codePoint = Character.codePointBefore(text, i);
if (Constants.CODE_DOUBLE_QUOTE == codePoint) {
// If we see a double quote followed by whitespace, then that
// was a closing quote.
if (Character.isWhitespace(prevCodePoint)) {
return ignoredDoubleQuoteCount % 2 == 1;
}
}
if (Character.isWhitespace(codePoint) && Constants.CODE_DOUBLE_QUOTE == prevCodePoint) {
// If we see a double quote preceded by whitespace, then that
// was an opening quote. No need to continue seeking.
return ignoredDoubleQuoteCount % 2 == 0;
}
if (Constants.CODE_DOUBLE_QUOTE == prevCodePoint) {
ignoredDoubleQuoteCount++;
}
i -= Character.charCount(codePoint);
prevCodePoint = codePoint;
}
// We reached the start of text. If the first char is a double quote, then we're inside
// a double quote. Otherwise we're not.
if (ignoredDoubleQuoteCount % 2 == 0)
return Constants.CODE_DOUBLE_QUOTE == codePoint;
else
return Constants.CODE_DOUBLE_QUOTE != codePoint;
}
public static boolean isEmptyStringOrWhiteSpaces(@NonNull final String s) {
final int N = codePointCount(s);
for (int i = 0; i < N; ++i) {
if (!Character.isWhitespace(s.codePointAt(i))) {
return false;
}
}
return true;
}
private static final String LANGUAGE_GREEK = "el";
@NonNull
private static Locale getLocaleUsedForToTitleCase(@NonNull final Locale locale) {
// In Greek locale {@link String#toUpperCase(Locale)} eliminates accents from its result.
// In order to get accented upper case letter, {@link Locale#ROOT} should be used.
if (LANGUAGE_GREEK.equals(locale.getLanguage())) {
return Locale.ROOT;
}
return locale;
}
@Nullable
public static String toTitleCaseOfKeyLabel(@Nullable final String label,
@NonNull final Locale locale) {
if (label == null || !ScriptUtils.scriptSupportsUppercase(locale)) {
return label;
}
if (label.equals("ß"))
return ""; // upcasing of standalone ß, SS is not useful as s is on the keyboard anyway
return label.toUpperCase(getLocaleUsedForToTitleCase(locale));
}
public static int toTitleCaseOfKeyCode(final int code, @NonNull final Locale locale) {
if (!Constants.isLetterCode(code)) {
return code;
}
final String label = newSingleCodePointString(code);
final String titleCaseLabel = toTitleCaseOfKeyLabel(label, locale);
return codePointCount(titleCaseLabel) == 1
? titleCaseLabel.codePointAt(0) : KeyCode.NOT_SPECIFIED;
}
public static int getTrailingSingleQuotesCount(@NonNull final CharSequence charSequence) {
final int lastIndex = charSequence.length() - 1;
int i = lastIndex;
while (i >= 0 && charSequence.charAt(i) == Constants.CODE_SINGLE_QUOTE) {
--i;
}
return lastIndex - i;
}
/**
* Returns whether the last composed word contains line-breaking character (e.g. CR or LF).
*
* @param text the text to be examined.
* @return {@code true} if the last composed word contains line-breaking separator.
*/
public static boolean hasLineBreakCharacter(@Nullable final String text) {
if (isEmpty(text)) {
return false;
}
for (int i = text.length() - 1; i >= 0; --i) {
final char c = text.charAt(i);
switch (c) {
case CHAR_LINE_FEED:
case CHAR_VERTICAL_TAB:
case CHAR_FORM_FEED:
case CHAR_CARRIAGE_RETURN:
case CHAR_NEXT_LINE:
case CHAR_LINE_SEPARATOR:
case CHAR_PARAGRAPH_SEPARATOR:
return true;
}
}
return false;
}
public static boolean mightBeEmoji(final CharSequence s) {
int offset = 0;
final int length = s.length();
while (offset < length) {
int c = Character.codePointAt(s, offset);
if (mightBeEmoji(c))
return true;
offset += Character.charCount(c);
}
return false;
}
// unicode blocks that contain emojis
// very fast check, but there are very few blocks that exclusively contain emojis,
public static boolean mightBeEmoji(final int c) {
return (0x200D <= c && c <= 0x2BFF) // unicode blocks from General Punctuation to Miscellaneous Symbols and Arrows
|| (0x1F104 <= c && c <= 0x1FAFF) // unicode blocks from Mahjong Tiles to Symbols and Pictographs Extended-A
|| (0xE0000 <= c && c <= 0xE007F) // unicode block Tags
|| c == 0xFE0F; // variation selector emoji with color
}
public static boolean isLowerCaseAscii(final String s) {
final int length = s.length();
for (int i = 0; i < length; i++) {
final int c = s.charAt(i);
if (c < 97 || c > 122) return false;
}
return true;
}
public static int charIndexOfFirstWhitespace(final CharSequence s) {
for (int i = 0; i < s.length() - 1; i++) {
final char c = s.charAt(i);
if (Character.isWhitespace(c)) {
return i + 1;
}
}
return -1;
}
public static int charIndexOfLastWhitespace(final CharSequence s) {
for (int i = s.length() - 1; i >= 0; i--) {
final char c = s.charAt(i);
if (Character.isWhitespace(c)) {
return i + 1;
}
}
return -1;
}
}