MC ASCII Font Loader

SimpleFontLoader.java

package net.minecraftforge.fml.client;

import com.google.common.base.CharMatcher;
import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import com.google.gson.JsonArray;
import com.google.gson.JsonObject;
import net.minecraft.client.Minecraft;
import net.minecraft.client.gui.FontRenderer;
import net.minecraft.client.gui.fonts.Font;
import net.minecraft.client.gui.fonts.providers.GlyphProviderTypes;
import net.minecraft.client.gui.fonts.providers.IGlyphProvider;
import net.minecraft.client.renderer.texture.TextureManager;
import net.minecraft.resources.FallbackResourceManager;
import net.minecraft.resources.IResourcePack;
import net.minecraft.resources.ResourcePackType;
import net.minecraft.util.JSONUtils;
import net.minecraft.util.ResourceLocation;
import net.minecraftforge.fml.SidedProvider;
import org.apache.commons.io.IOUtils;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;
import java.io.IOException;
import java.io.InputStream;
import java.nio.charset.StandardCharsets;
import java.util.Arrays;
import java.util.function.Function;
import static net.minecraftforge.fml.Logging.SPLASH;

public class SimpleFontLoader
{
    private static Logger LOGGER = LogManager.getLogger();
    private static FallbackResourceManager resourceManager = new FallbackResourceManager(ResourcePackType.CLIENT_RESOURCES);
    private static TextureManager textureManager = new TextureManager(resourceManager);
    private static IResourcePack mcPack = Minecraft.getInstance().getPackFinder().getVanillaPack();

    private static String allowedChars;
    private static CharMatcher disallowedCharMatcher;

    static
    {
        resourceManager.addResourcePack(mcPack);
    }

    public static String stripChars(String message)
    {
        if (disallowedCharMatcher == null) return SidedProvider.STRIPCHARS.<Function<String, String>>get().apply(message);
        return disallowedCharMatcher.removeFrom(net.minecraft.util.StringUtils.stripControlCodes(message));
    }

    public static void cleanup()
    {
        resourceManager = null;
        textureManager = null;
        mcPack = null;
        allowedChars = null;
        disallowedCharMatcher = null;
    }

    public static FontRenderer getFontRenderer()
    {
        return loadFont(new ResourceLocation("font/default.json"), new ResourceLocation("font/ascii.png"));
    }

    private static FontRenderer loadFont(ResourceLocation fontJsonLoc, ResourceLocation fontTextureLoc)
    {
        FontRenderer fontRenderer;
        try(InputStream s = mcPack.getResourceStream(ResourcePackType.CLIENT_RESOURCES, fontJsonLoc))
        {
            Gson gson = (new GsonBuilder()).setPrettyPrinting().disableHtmlEscaping().create();
            JsonArray jsonarray = JSONUtils.getJsonArray(JSONUtils.fromJson(gson, IOUtils.toString(s, StandardCharsets.UTF_8), JsonObject.class), "providers");

            for(int i = jsonarray.size() - 1; i >= 0; --i)
            {
                JsonObject provider = JSONUtils.getJsonObject(jsonarray.get(i), "providers[" + i + "]");
                if (JSONUtils.hasField(provider, "file"))
                {
                    String id = JSONUtils.getString(provider, "file");
                    if (id.equals(fontTextureLoc.toString()))
                    {
                        GlyphProviderTypes providerType = GlyphProviderTypes.byName(JSONUtils.getString(provider, "type"));
                        IGlyphProvider iglyphprovider = providerType.getFactory(provider).create(resourceManager);

                        if (iglyphprovider == null) throw new RuntimeException("Error creating glyph provider");

                        fontRenderer = new FontRenderer(textureManager, new Font(textureManager, new ResourceLocation(id)));
                        fontRenderer.setGlyphProviders(Arrays.asList(iglyphprovider));

                        allowedChars = "";
                        if (JSONUtils.hasField(provider, "chars"))
                        {
                            JsonArray charArray = JSONUtils.getJsonArray(provider, "chars");
                            charArray.forEach(e -> allowedChars = allowedChars.concat(e.getAsString()));
                            disallowedCharMatcher = CharMatcher.anyOf(allowedChars).negate();
                        }
                        else
                        {
                            disallowedCharMatcher = null;
                        }
                        return fontRenderer;
                    }
                }
            }

            throw new RuntimeException("Could not find provider for " + fontTextureLoc);
        }
        catch(IOException | RuntimeException e)
        {
            LOGGER.error(SPLASH,"Error loading font json from file: {}", fontJsonLoc, e);
            throw new RuntimeException(e);
        }
    }
}