/******************************************************************************
 * Spine Runtimes License Agreement
 * Last updated April 5, 2025. Replaces all prior versions.
 *
 * Copyright (c) 2013-2025, Esoteric Software LLC
 *
 * Integration of the Spine Runtimes into software or otherwise creating
 * derivative works of the Spine Runtimes is permitted under the terms and
 * conditions of Section 2 of the Spine Editor License Agreement:
 * http://esotericsoftware.com/spine-editor-license
 *
 * Otherwise, it is permitted to integrate the Spine Runtimes into software
 * or otherwise create derivative works of the Spine Runtimes (collectively,
 * "Products"), provided that each user of the Products must obtain their own
 * Spine Editor license and redistribution of the Products in any form must
 * include this license and copyright notice.
 *
 * THE SPINE RUNTIMES ARE PROVIDED BY ESOTERIC SOFTWARE LLC "AS IS" AND ANY
 * EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
 * WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
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 *****************************************************************************/

#ifndef Spine_BlockAllocator_h
#define Spine_BlockAllocator_h

#include <cstdint>
#include <spine/SpineObject.h>
#include <spine/Extension.h>
#include <spine/MathUtil.h>
#include <spine/Array.h>

namespace spine {
	struct Block {
		int size;
		int allocated;
		uint8_t *memory;

		int free() {
			return size - allocated;
		}

		bool canFit(int numBytes) {
			return free() >= numBytes;
		}

		uint8_t *allocate(int numBytes) {
			uint8_t *ptr = memory + allocated;
			allocated += numBytes;
			return ptr;
		}
	};

	class BlockAllocator : public SpineObject {
		int initialBlockSize;
		Array<Block> blocks;

	public:
		BlockAllocator(int initialBlockSize) : initialBlockSize(initialBlockSize) {
			blocks.add(newBlock(initialBlockSize));
		}

		~BlockAllocator() {
			for (int i = 0, n = (int) blocks.size(); i < n; i++) {
				SpineExtension::free(blocks[i].memory, __FILE__, __LINE__);
			}
		}

		template<typename T>
		T *allocate(size_t num) {
			return (T *) _allocate((int) (sizeof(T) * num));
		}

		void compress() {
			if (blocks.size() == 1) {
				blocks[0].allocated = 0;
				return;
			}
			int totalSize = 0;
			for (int i = 0, n = (int) blocks.size(); i < n; i++) {
				totalSize += blocks[i].size;
				SpineExtension::free(blocks[i].memory, __FILE__, __LINE__);
			}
			blocks.clear();
			blocks.add(newBlock(totalSize));
		}

	private:
		void *_allocate(int numBytes) {
			// 16-byte align allocations
			int alignedNumBytes = numBytes + (numBytes % 16 != 0 ? 16 - (numBytes % 16) : 0);
			Block *block = &blocks[blocks.size() - 1];
			if (!block->canFit(alignedNumBytes)) {
				blocks.add(newBlock(MathUtil::max(initialBlockSize, alignedNumBytes)));
				block = &blocks[blocks.size() - 1];
			}
			return block->allocate(alignedNumBytes);
		}

		Block newBlock(int numBytes) {
			Block block = {MathUtil::max(initialBlockSize, numBytes), 0, nullptr};
			block.memory = SpineExtension::alloc<uint8_t>(block.size, __FILE__, __LINE__);
			return block;
		}
	};
}

#endif