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package org.graalvm.wasm;

import com.oracle.truffle.api.CompilerDirectives.CompilationFinal;
import org.graalvm.wasm.memory.WasmMemory;

import java.util.function.BiFunction;

public class MemoryRegistry {
    private static final int INITIAL_MEMORIES_SIZE = 4;

    @CompilationFinal(dimensions = 1) private WasmMemory[] memories;
    private int numMemories;

    public MemoryRegistry() {
        this.memories = new WasmMemory[INITIAL_MEMORIES_SIZE];
        this.numMemories = 0;
    }

    private void ensureCapacity() {
        if (numMemories == memories.length) {
            final WasmMemory[] updatedMemories = new WasmMemory[memories.length * 2];
            System.arraycopy(memories, 0, updatedMemories, 0, memories.length);
            memories = updatedMemories;
        }
    }

    public int count() {
        return numMemories;
    }

    private int allocateMemoryWith(WasmMemory memory) {
        ensureCapacity();
        memories[numMemories] = memory;
        int idx = numMemories;
        numMemories++;
        return idx;
    }

    public int allocateExternalMemory(WasmMemory externalMemory) {
        return allocateMemoryWith(externalMemory);
    }

    public int allocateMemory(SymbolTable.MemoryInfo info, BiFunction<Integer, Integer, WasmMemory> makeMemory) {
        return allocateMemoryWith(makeMemory.apply(info.initialSize, info.maximumSize));
    }

    public WasmMemory memory(int index) {
        assert index < numMemories;
        return memories[index];
    }
}