(svn r1763) -Add: pool.c / pool.h: generalized routines for dynamic arrays (MemoryPools)

pool.h

@@ -0,0 +1,53 @@
+#ifndef POOL_H
+#define POOL_H
+
+typedef struct MemoryPool MemoryPool;
+
+/* The function that is called after a new block is added
+     start_item is the first item of the new made block */
+typedef void MemoryPoolNewBlock(uint start_item);
+
+/**
+ * Stuff for dynamic vehicles. Use the wrappers to access the MemoryPool
+ *  please try to avoid manual calls!
+ */
+struct MemoryPool {
+	const char name[10];        //! Name of the pool (just for debugging)
+
+	const uint max_blocks;      //! The max amount of blocks this pool can have
+	const uint block_size_bits; //! The size of each block in bits
+	const uint item_size;       //! How many bytes one block is
+
+	MemoryPoolNewBlock *new_block_proc;
+	//!< Pointer to a function that is called after a new block is added
+
+	uint current_blocks;        //! How many blocks we have in our pool
+	uint total_items;           //! How many items we now have in this pool
+
+	byte **blocks;              //! An array of blocks (one block hold all the items)
+};
+
+/**
+ * Those are the wrappers:
+ *   CleanPool cleans the pool up, but you can use AddBlockToPool directly again
+ *     (no need to call CreatePool!)
+ *   AddBlockToPool adds 1 more block to the pool. Returns false if there is no
+ *     more room
+ */
+void CleanPool(MemoryPool *array);
+bool AddBlockToPool(MemoryPool *array);
+
+/**
+ * Adds blocks to the pool if needed (and possible) till index fits inside the pool
+ *
+ * @return Returns false if adding failed
+ */
+bool AddBlockIfNeeded(MemoryPool *array, uint index);
+
+static inline byte *GetItemFromPool(MemoryPool *pool, uint index)
+{
+	assert(index < pool->total_items);
+	return (pool->blocks[index >> pool->block_size_bits] + (index & ((1 << pool->block_size_bits) - 1)) * pool->item_size);
+}
+
+#endif /* POOL_H */