Code/net/minecraft/util/StringDecomposer.java

package net.minecraft.util;

import java.util.Optional;
import net.minecraft.ChatFormatting;
import net.minecraft.network.chat.FormattedText;
import net.minecraft.network.chat.Style;

public class StringDecomposer {
    private static final char REPLACEMENT_CHAR = '\ufffd';
    private static final Optional<Object> STOP_ITERATION = Optional.of(Unit.INSTANCE);

    private static boolean feedChar(Style p_14333_, FormattedCharSink p_14334_, int p_14335_, char p_14336_) {
        return Character.isSurrogate(p_14336_) ? p_14334_.accept(p_14335_, p_14333_, 65533) : p_14334_.accept(p_14335_, p_14333_, p_14336_);
    }

    public static boolean iterate(String p_14318_, Style p_14319_, FormattedCharSink p_14320_) {
        int i = p_14318_.length();

        for (int j = 0; j < i; j++) {
            char c0 = p_14318_.charAt(j);
            if (Character.isHighSurrogate(c0)) {
                if (j + 1 >= i) {
                    if (!p_14320_.accept(j, p_14319_, 65533)) {
                        return false;
                    }
                    break;
                }

                char c1 = p_14318_.charAt(j + 1);
                if (Character.isLowSurrogate(c1)) {
                    if (!p_14320_.accept(j, p_14319_, Character.toCodePoint(c0, c1))) {
                        return false;
                    }

                    j++;
                } else if (!p_14320_.accept(j, p_14319_, 65533)) {
                    return false;
                }
            } else if (!feedChar(p_14319_, p_14320_, j, c0)) {
                return false;
            }
        }

        return true;
    }

    public static boolean iterateBackwards(String p_14338_, Style p_14339_, FormattedCharSink p_14340_) {
        int i = p_14338_.length();

        for (int j = i - 1; j >= 0; j--) {
            char c0 = p_14338_.charAt(j);
            if (Character.isLowSurrogate(c0)) {
                if (j - 1 < 0) {
                    if (!p_14340_.accept(0, p_14339_, 65533)) {
                        return false;
                    }
                    break;
                }

                char c1 = p_14338_.charAt(j - 1);
                if (Character.isHighSurrogate(c1)) {
                    if (!p_14340_.accept(--j, p_14339_, Character.toCodePoint(c1, c0))) {
                        return false;
                    }
                } else if (!p_14340_.accept(j, p_14339_, 65533)) {
                    return false;
                }
            } else if (!feedChar(p_14339_, p_14340_, j, c0)) {
                return false;
            }
        }

        return true;
    }

    public static boolean iterateFormatted(String p_14347_, Style p_14348_, FormattedCharSink p_14349_) {
        return iterateFormatted(p_14347_, 0, p_14348_, p_14349_);
    }

    public static boolean iterateFormatted(String p_14307_, int p_14308_, Style p_14309_, FormattedCharSink p_14310_) {
        return iterateFormatted(p_14307_, p_14308_, p_14309_, p_14309_, p_14310_);
    }

    public static boolean iterateFormatted(String p_14312_, int p_14313_, Style p_14314_, Style p_14315_, FormattedCharSink p_14316_) {
        int i = p_14312_.length();
        Style style = p_14314_;

        for (int j = p_14313_; j < i; j++) {
            char c0 = p_14312_.charAt(j);
            if (c0 == 167) {
                if (j + 1 >= i) {
                    break;
                }

                char c1 = p_14312_.charAt(j + 1);
                ChatFormatting chatformatting = ChatFormatting.getByCode(c1);
                if (chatformatting != null) {
                    style = chatformatting == ChatFormatting.RESET ? p_14315_ : style.applyLegacyFormat(chatformatting);
                }

                j++;
            } else if (Character.isHighSurrogate(c0)) {
                if (j + 1 >= i) {
                    if (!p_14316_.accept(j, style, 65533)) {
                        return false;
                    }
                    break;
                }

                char c2 = p_14312_.charAt(j + 1);
                if (Character.isLowSurrogate(c2)) {
                    if (!p_14316_.accept(j, style, Character.toCodePoint(c0, c2))) {
                        return false;
                    }

                    j++;
                } else if (!p_14316_.accept(j, style, 65533)) {
                    return false;
                }
            } else if (!feedChar(style, p_14316_, j, c0)) {
                return false;
            }
        }

        return true;
    }

    public static boolean iterateFormatted(FormattedText p_14329_, Style p_14330_, FormattedCharSink p_14331_) {
        return p_14329_.visit((p_14302_, p_14303_) -> iterateFormatted(p_14303_, 0, p_14302_, p_14331_) ? Optional.empty() : STOP_ITERATION, p_14330_).isEmpty();
    }

    public static String filterBrokenSurrogates(String p_14305_) {
        StringBuilder stringbuilder = new StringBuilder();
        iterate(p_14305_, Style.EMPTY, (p_14343_, p_14344_, p_14345_) -> {
            stringbuilder.appendCodePoint(p_14345_);
            return true;
        });
        return stringbuilder.toString();
    }

    public static String getPlainText(FormattedText p_14327_) {
        StringBuilder stringbuilder = new StringBuilder();
        iterateFormatted(p_14327_, Style.EMPTY, (p_14323_, p_14324_, p_14325_) -> {
            stringbuilder.appendCodePoint(p_14325_);
            return true;
        });
        return stringbuilder.toString();
    }
}