+++ /dev/null
-// © 2017 and later: Unicode, Inc. and others.
-// License & terms of use: http://www.unicode.org/copyright.html#License
-package com.ibm.icu.impl.number.parse;
-
-import com.ibm.icu.lang.UCharacter;
-import com.ibm.icu.text.UnicodeSet;
-
-/**
- * A mutable class allowing for a String with a variable offset and length. The charAt, length, and
- * subSequence methods all operate relative to the fixed offset into the String.
- *
- * TODO: Make sure that this operates only on code point boundaries.
- *
- * @author sffc
- */
-public class StringSegment implements CharSequence {
- private final String str;
- private int start;
- private int end;
- private boolean foldCase;
-
- public StringSegment(String str, int parseFlags) {
- this.str = str;
- this.start = 0;
- this.end = str.length();
- this.foldCase = 0 != (parseFlags & ParsingUtils.PARSE_FLAG_IGNORE_CASE);
- }
-
- public int getOffset() {
- return start;
- }
-
- public void setOffset(int start) {
- assert start <= end;
- this.start = start;
- }
-
- /**
- * Equivalent to <code>setOffset(getOffset()+delta)</code>.
- *
- * <p>
- * This method is usually called by a Matcher to register that a char was consumed. If the char is
- * strong (it usually is, except for things like whitespace), follow this with a call to
- * {@link ParsedNumber#setCharsConsumed}. For more information on strong chars, see that method.
- */
- public void adjustOffset(int delta) {
- assert start + delta >= 0;
- assert start + delta <= end;
- start += delta;
- }
-
- /**
- * Adjusts the offset by the width of the current code point, either 1 or 2 chars.
- */
- public void adjustOffsetByCodePoint() {
- start += Character.charCount(getCodePoint());
- }
-
- public void setLength(int length) {
- assert length >= 0;
- assert start + length <= str.length();
- end = start + length;
- }
-
- public void resetLength() {
- end = str.length();
- }
-
- @Override
- public int length() {
- return end - start;
- }
-
- @Override
- public char charAt(int index) {
- return str.charAt(index + start);
- }
-
- public int codePointAt(int index) {
- return str.codePointAt(index + start);
- }
-
- @Override
- public CharSequence subSequence(int start, int end) {
- throw new AssertionError(); // Never used
- // Possible implementation:
- // return str.subSequence(start + this.start, end + this.start);
- }
-
- /**
- * Returns the first code point in the string segment, or -1 if the string starts with an invalid
- * code point.
- *
- * <p>
- * <strong>Important:</strong> Most of the time, you should use {@link #matches}, which handles case
- * folding logic, instead of this method.
- */
- public int getCodePoint() {
- assert start < end;
- char lead = str.charAt(start);
- char trail;
- if (Character.isHighSurrogate(lead)
- && start + 1 < end
- && Character.isLowSurrogate(trail = str.charAt(start + 1))) {
- return Character.toCodePoint(lead, trail);
- }
- return lead;
- }
-
- /**
- * Returns true if the first code point of this StringSegment equals the given code point.
- *
- * <p>
- * This method will perform case folding if case folding is enabled for the parser.
- */
- public boolean matches(int otherCp) {
- return codePointsEqual(getCodePoint(), otherCp, foldCase);
- }
-
- /**
- * Returns true if the first code point of this StringSegment is in the given UnicodeSet.
- */
- public boolean matches(UnicodeSet uniset) {
- // TODO: Move UnicodeSet case-folding logic here.
- // TODO: Handle string matches here instead of separately.
- int cp = getCodePoint();
- if (cp == -1) {
- return false;
- }
- return uniset.contains(cp);
- }
-
- /**
- * Returns the length of the prefix shared by this StringSegment and the given CharSequence. For
- * example, if this string segment is "aab", and the char sequence is "aac", this method returns 2,
- * since the first 2 characters are the same.
- *
- * <p>
- * This method will perform case folding if case folding is enabled for the parser.
- */
- public int getCommonPrefixLength(CharSequence other) {
- return getPrefixLengthInternal(other, foldCase);
- }
-
- /**
- * Like {@link #getCommonPrefixLength}, but never performs case folding, even if case folding is
- * enabled for the parser.
- */
- public int getCaseSensitivePrefixLength(CharSequence other) {
- return getPrefixLengthInternal(other, false);
- }
-
- private int getPrefixLengthInternal(CharSequence other, boolean foldCase) {
- int offset = 0;
- for (; offset < Math.min(length(), other.length());) {
- // TODO: case-fold code points, not chars
- char c1 = charAt(offset);
- char c2 = other.charAt(offset);
- if (!codePointsEqual(c1, c2, foldCase)) {
- break;
- }
- offset++;
- }
- return offset;
- }
-
- // /**
- // * Case-folds the string if IGNORE_CASE flag is set; otherwise, returns the same string.
- // */
- // public static String maybeFold(String input, int parseFlags) {
- // UnicodeSet cwcf = UnicodeSetStaticCache.get(UnicodeSetStaticCache.Key.CWCF);
- // if (0 != (parseFlags & ParsingUtils.PARSE_FLAG_IGNORE_CASE) && cwcf.containsSome(input)) {
- // return UCharacter.foldCase(input, true);
- // } else {
- // return input;
- // }
- // }
-
- private static final boolean codePointsEqual(int cp1, int cp2, boolean foldCase) {
- if (cp1 == cp2) {
- return true;
- }
- if (!foldCase) {
- return false;
- }
- cp1 = UCharacter.foldCase(cp1, true);
- cp2 = UCharacter.foldCase(cp2, true);
- return cp1 == cp2;
- }
-
- @Override
- public String toString() {
- return str.substring(0, start) + "[" + str.substring(start, end) + "]" + str.substring(end);
- }
-}
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