feather-rs · caelunshun · Jun 11, 2020
diff --git a/Cargo.lock b/Cargo.lock
diff --git a/Cargo.toml b/Cargo.toml
@@ -9,6 +9,7 @@ members = [
     "core/biomes",
     "core/chunk",
     "core/chunk_map",
+    "core/crafting",
     "core/entity_metadata",
     "core/item_block",
     "core/items",

diff --git a/core/crafting/Cargo.toml b/core/crafting/Cargo.toml
@@ -0,0 +1,15 @@
+[package]
+name = "feather-crafting"
+version = "0.1.0"
+authors = ["caelunshun <caelunshun@gmail.com>"]
+edition = "2018"
+
+[dependencies]
+feather-items = { path = "../items" }
+
+serde = { version = "1.0", features = ["derive"] }
+serde_json = "1.0"
+smallvec = "1.4"
+arrayvec = { version = "0.5", features = ["serde"] }
+anyhow = "1.0"
+ahash = "0.3"
diff --git a/core/crafting/src/lib.rs b/core/crafting/src/lib.rs
@@ -0,0 +1,19 @@
+//! Loading of recipe files and crafting algorithms ("solving").
+
+use feather_items::Item;
+
+mod model;
+mod recipe;
+mod solver;
+
+pub use recipe::convert;
+pub use solver::{transpose, Solver};
+
+pub const TABLE_WIDTH: usize = 3;
+pub const TABLE_SIZE: usize = TABLE_WIDTH * TABLE_WIDTH;
+
+/// A crafting grid. Origin is at the upper left corner.
+/// Stored in column-major format. Indexing by [x][y]
+/// will yield the item `x` slots from the left
+/// and `y` slots from the top.
+pub type Grid = [[Option<Item>; TABLE_WIDTH]; TABLE_WIDTH];
diff --git a/core/crafting/src/model.rs b/core/crafting/src/model.rs
@@ -0,0 +1,47 @@
+//! Serde data model for recipe files.
+use crate::{TABLE_SIZE, TABLE_WIDTH};
+use arrayvec::{ArrayString, ArrayVec};
+use serde::{Deserialize, Serialize};
+use std::collections::BTreeMap;
+
+pub type TableEntry = ArrayString<[u8; TABLE_WIDTH]>;
+pub type Table = ArrayVec<[TableEntry; TABLE_WIDTH]>;
+
+#[derive(Debug, Serialize, Deserialize)]
+#[serde(tag = "type")]
+pub enum Recipe<'a> {
+    #[serde(rename = "minecraft:crafting_shaped")]
+    Shaped {
+        pattern: Table,
+        #[serde(borrow)]
+        key: BTreeMap<char, Key<'a>>,
+        #[serde(rename = "result")]
+        output: Output<'a>,
+    },
+    #[serde(rename = "minecraft:crafting_shapeless")]
+    Shapeless {
+        ingredients: ArrayVec<[Key<'a>; TABLE_SIZE]>,
+        #[serde(rename = "result")]
+        output: Output<'a>,
+    },
+}
+
+#[derive(Debug, Serialize, Deserialize)]
+#[serde(untagged)]
+#[serde(rename_all = "lowercase")]
+pub enum Key<'a> {
+    Item(&'a str),
+    Tag(&'a str),
+}
+
+#[derive(Debug, Serialize, Deserialize)]
+pub struct Output<'a> {
+    /// Identifier of output item.
+    pub item: &'a str,
+    #[serde(default = "one")]
+    pub count: u8,
+}
+
+const fn one() -> u8 {
+    1
+}
diff --git a/core/crafting/src/recipe.rs b/core/crafting/src/recipe.rs
@@ -0,0 +1,150 @@
+//! Intermediate representation of a recipe used directly
+//! in solving.
+
+use crate::{model, solver, Grid, TABLE_SIZE};
+use anyhow::anyhow;
+use arrayvec::ArrayVec;
+use feather_items::{Item, ItemStack};
+use std::collections::BTreeMap;
+
+#[derive(Clone, Debug)]
+pub struct ShapedRecipe {
+    /// Input grid of required items.
+    /// Normalized to the upper left corner:
+    /// all empty rows on top and all empty
+    /// columns to the left are removed.
+    pub input: Grid,
+    /// Output item stack.
+    pub output: ItemStack,
+}
+
+#[derive(Clone, Debug)]
+pub struct ShapelessRecipe {
+    /// The set of input items required.
+    /// Must be a sorted vector to allow for efficient
+    /// comparison.
+    pub input: ArrayVec<[Item; TABLE_SIZE]>,
+    /// Output item stack.
+    pub output: ItemStack,
+}
+
+#[derive(Clone, Debug)]
+pub enum Recipe {
+    Shaped(ShapedRecipe),
+    Shapeless(ShapelessRecipe),
+}
+
+/// Converts a `model::Recipe` to a `Recipe`.
+pub fn convert(model: model::Recipe) -> anyhow::Result<Recipe> {
+    match model {
+        model::Recipe::Shaped {
+            pattern,
+            key,
+            output,
+        } => convert_shaped(pattern, key, output),
+        model::Recipe::Shapeless {
+            ingredients,
+            output,
+        } => convert_shapeless(&ingredients, output),
+    }
+}
+
+fn convert_shaped(
+    pattern: model::Table,
+    key: BTreeMap<char, model::Key>,
+    output: model::Output,
+) -> anyhow::Result<Recipe> {
+    let mut input = Grid::default();
+
+    for (y, row) in pattern.iter().enumerate() {
+        for (x, slot) in row.as_str().chars().enumerate() {
+            let key = key
+                .get(&slot)
+                .ok_or_else(|| anyhow!("no entry in key for character '{}'", slot))?;
+
+            let item = convert_key(key)?;
+
+            if let Some(item) = item {
+                input[x][y] = Some(item);
+            }
+        }
+    }
+
+    solver::normalize(&mut input);
+
+    let output = convert_output(&output)?;
+
+    Ok(Recipe::Shaped(ShapedRecipe { input, output }))
+}
+
+fn convert_shapeless(ingredients: &[model::Key], output: model::Output) -> anyhow::Result<Recipe> {
+    let mut input = ArrayVec::new();
+
+    for ingredient in ingredients {
+        let item = convert_key(ingredient)?;
+
+        if let Some(item) = item {
+            input.push(item);
+        }
+    }
+
+    input.sort_unstable();
+
+    let output = convert_output(&output)?;
+
+    Ok(Recipe::Shapeless(ShapelessRecipe { input, output }))
+}
+
+fn convert_key(key: &model::Key) -> anyhow::Result<Option<Item>> {
+    match key {
+        model::Key::Item(identifier) => Ok(Some(
+            Item::from_identifier(*identifier)
+                .ok_or_else(|| anyhow!("invalid item '{}'", identifier))?,
+        )),
+        model::Key::Tag(_) => Ok(None), // not implemented
+    }
+}
+
+fn convert_output(output: &model::Output) -> anyhow::Result<ItemStack> {
+    let ty = Item::from_identifier(output.item)
+        .ok_or_else(|| anyhow!("invalid item '{}'", output.item))?;
+    Ok(ItemStack::new(ty, output.count))
+}
+
+#[cfg(test)]
+mod tests {
+    use super::*;
+
+    #[test]
+    fn test_convert_output() {
+        assert_eq!(
+            convert_output(&model::Output {
+                item: "minecraft:stone",
+                count: 5
+            })
+            .unwrap(),
+            ItemStack::new(Item::Stone, 5)
+        );
+    }
+
+    #[test]
+    fn test_convert_output_invalid_item() {
+        assert!(convert_output(&model::Output {
+            item: "minecraft:doesnotexist",
+            count: 1
+        })
+        .is_err());
+    }
+
+    #[test]
+    fn test_convert_key() {
+        assert_eq!(
+            convert_key(&model::Key::Item("minecraft:diamond_sword")).unwrap(),
+            Some(Item::DiamondSword)
+        );
+        assert_eq!(
+            convert_key(&model::Key::Tag("unimplemented")).unwrap(),
+            None
+        );
+    }
+}