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

Makefile

@@ -600,6 +600,7 @@ C_SOURCES += order_gui.c
 C_SOURCES += pathfind.c
 C_SOURCES += player_gui.c
 C_SOURCES += players.c
+C_SOURCES += pool.c
 C_SOURCES += queue.c
 C_SOURCES += rail_cmd.c
 C_SOURCES += rail_gui.c

pool.c

@@ -0,0 +1,79 @@
+#include "stdafx.h"
+#include "ttd.h"
+#include "pool.h"
+
+/**
+ * Clean a pool in a safe way (does free all blocks)
+ */
+void CleanPool(MemoryPool *pool)
+{
+	uint i;
+
+	DEBUG(misc, 4)("[Pool] (%s) Cleaing pool..", pool->name);
+
+	/* Free all blocks */
+	for (i = 0; i < pool->current_blocks; i++)
+		free(pool->blocks[i]);
+
+	/* Free the block itself */
+	free(pool->blocks);
+
+	/* Clear up some critical data */
+	pool->total_items = 0;
+	pool->current_blocks = 0;
+	pool->blocks = NULL;
+}
+
+/**
+ * This function tries to increase the size of array by adding
+ *  1 block too it
+ *
+ * @return Returns false if the pool could not be increased
+ */
+bool AddBlockToPool(MemoryPool *pool)
+{
+	/* Is the pool at his max? */
+	if (pool->max_blocks == pool->current_blocks)
+		return false;
+
+	pool->total_items = (pool->current_blocks + 1) * (1 << pool->block_size_bits);
+
+	DEBUG(misc, 4)("[Pool] (%s) Increasing size of pool to %d items (%d bytes)", pool->name, pool->total_items, pool->total_items * pool->item_size);
+
+	/* Increase the poolsize */
+	pool->blocks = realloc(pool->blocks, sizeof(pool->blocks[0]) * (pool->current_blocks + 1));
+	if (pool->blocks == NULL)
+		error("Pool: (%s) could not allocate memory for blocks", pool->name);
+
+	/* Allocate memory to the new block item */
+	pool->blocks[pool->current_blocks] = malloc(pool->item_size * (1 << pool->block_size_bits));
+	if (pool->blocks[pool->current_blocks] == NULL)
+		error("Pool: (%s) could not allocate memory for blocks", pool->name);
+
+	/* Clean the content of the new block */
+	memset(pool->blocks[pool->current_blocks], 0, pool->item_size * (1 << pool->block_size_bits));
+
+	/* Call a custom function if defined (e.g. to fill indexes) */
+	if (pool->new_block_proc != NULL)
+		pool->new_block_proc(pool->current_blocks * (1 << pool->block_size_bits));
+
+	/* We have a new block */
+	pool->current_blocks++;
+
+	return true;
+}
+
+/**
+ * Adds blocks to the pool if needed (and possible) till index fits inside the pool
+ *
+ * @return Returns false if adding failed
+ */
+bool AddBlockIfNeeded(MemoryPool *pool, uint index)
+{
+	while (index >= pool->total_items) {
+		if (!AddBlockToPool(pool))
+			return false;
+	}
+
+	return true;
+}

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 */

ttd.dsp

@@ -276,6 +276,10 @@ SOURCE=.\oldloader.c
 SOURCE=.\pathfind.c
 # End Source File
 
+# Begin Source File
+SOURCE=.\pool.c
+# End Source File
+
 # Begin Source File
 SOURCE=.\players.c
 # End Source File
@@ -513,6 +517,10 @@ SOURCE=.\npf.h
 SOURCE=.\pathfind.h
 # End Source File
 
+# Begin Source File
+SOURCE=.\pool.h
+# End Source File
+
 # Begin Source File
 SOURCE=.\player.h
 # End Source File

ttd.vcproj

@@ -690,6 +690,9 @@
 						BasicRuntimeChecks="3"/>
 				</FileConfiguration>
 			</File>
+			<File
+				RelativePath=".\pool.c">
+			</File>
 			<File
 				RelativePath=".\queue.c">
 			</File>
@@ -1223,6 +1226,9 @@
 			<File
 				RelativePath="player.h">
 			</File>
+			<File
+				RelativePath=".\pool.h">
+			</File>
 			<File
 				RelativePath=".\queue.h">
 			</File>