memory pool

memoryPool.c

#include <stdlib.h>
#include <string.h>
#include "memoryPool.h"

/* ストア */
typedef struct _store* store;
struct _store {
	store next;	/* 次ストア */
	void* data;	/* データ */
};

/* プールハンドル */
struct _poolHandle {
	long providableByte;	/* 提供可能なサイズ */
	void* candi;	/* 提供候補 */
	store first;
	store last;
};


poolHandle memoryPool_Create() {
	void* p = NULL;
	p = malloc( sizeof( struct _poolHandle ) );
	if( p ) {
		memset( p, 0x00, sizeof( struct _poolHandle ) );
	}
	return p;
}


void* memoryPool_Alloc( poolHandle handle, long byte ) {
	if( !handle || byte == 0 ) {
		return NULL;
	}
	if( ALLOC_BYTE < byte ) {
		return NULL;
	}

	if( byte <= handle->providableByte ) {
		/* 提供可能 */
		handle->providableByte -= byte;
		void* ret = handle->candi;
		(long)handle->candi += byte + 1;
		return ret;
	}
	else {
		/* 提供不可 */
		store s = ( store )malloc( sizeof( struct _store ) );
		if( !s ) {
			return NULL;
		}
		memset( s, 0x00, sizeof( struct _store ) );
		s->data = malloc( ALLOC_BYTE );
		if( !( s->data ) ) {
			return NULL;
		}
		memset( s->data, 0x00, ALLOC_BYTE );

		if( !( handle->first ) ) {
			/* 既存ストア無し */
			handle->first = handle->last = s;
		}
		else {
			/* 既存ストアあり */
			handle->last->next = s;
			handle->last = s;
		}

		handle->providableByte = ALLOC_BYTE - byte;
		//void* ret = handle->candi;
		handle->candi = (long)s->data + byte + 1;
		return ( long )s->data;
	}
}


void memoryPool_Release( poolHandle handle ) {
	if( !handle ) {
		return;
	}

	store s = handle->first;
	if( !s ) return;

	do {
		store t = s;
		s = s->next;

		free( t->data );
		free( t );
	} while( s );

	free( handle );
}

memoryPool.h

#pragma once


#define ALLOC_BYTE 1024	/* 一括確保サイズ */

typedef struct _poolHandle* poolHandle;	/* プールハンドル */


/**
 *生成。
 *
 *@return NULL以外:プールハンドル、NULL:失敗
*/
poolHandle memoryPool_Create();

/**
 *メモリ確保。
 *ALLOC_BYTEより大きいbyteは指定不可。
 *
 *@param handle プールハンドル
 *@param byte 確保するメモリ量(バイト)
 *@return NULL以外:メモリアドレス、NULL:失敗
*/
void* memoryPool_Alloc( poolHandle handle, long size );

/**
 *解放。
 *
 *@param handle
 */
void memoryPool_Release( poolHandle handle );

test_memoryPool.c

#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include "memoryPool.h"


void test1() {
	poolHandle h = NULL;
	h = memoryPool_Create();
	if( !h ) {
		printf( "memoryPool_Create() err\n" );
		exit( 1 );
	}
	int* i;
	if( !( i = ( int* )memoryPool_Alloc( h, sizeof( int ) ) ) ) {
		printf( "memoryPool_Alloc() err\n" );
		exit( 1 );
	}

	*i = 3;
	printf( "i=%d\n", *i );

	memoryPool_Release( h );
}

void test2() {
	poolHandle h = NULL;
	h = memoryPool_Create();
	if( !h ) {
		printf( "memoryPool_Create() err\n" );
		exit( 1 );
	}
	int* i;
	if( !( i = ( int* )memoryPool_Alloc( h, 1024 ) ) ) {
		printf( "memoryPool_Alloc() err\n" );
		exit( 1 );
	}
	if( !( i = ( int* )memoryPool_Alloc( h, 1024 ) ) ) {
		printf( "memoryPool_Alloc() err\n" );
		exit( 1 );
	}
	if( !( i = ( int* )memoryPool_Alloc( h, 1024 ) ) ) {
		printf( "memoryPool_Alloc() err\n" );
		exit( 1 );
	}

	memoryPool_Release( h );
}

void test4() {
	poolHandle h = NULL;
	h = memoryPool_Create();
	if( !h ) {
		printf( "memoryPool_Create() err\n" );
		exit( 1 );
	}
	

	int* i;
	if( !( i = ( int* )memoryPool_Alloc( h, 1024 ) ) ) {
		printf( "memoryPool_Alloc() err\n" );
		exit( 1 );
	}

	struct st {
		int a;
		long b;
		char* c;
	};

	struct st* p;
	if( !( p = ( struct st* )memoryPool_Alloc( h, sizeof(struct st) ) ) ) {
		printf( "memoryPool_Alloc() err\n" );
		exit( 1 );
	}
	if( !( p->c = ( char* )memoryPool_Alloc( h, 10 ) ) ) {
		printf( "memoryPool_Alloc() err\n" );
		exit( 1 );
	}
	if( !( i = ( int* )memoryPool_Alloc( h, 1024 ) ) ) {
		printf( "memoryPool_Alloc() err\n" );
		exit( 1 );
	}

	p->a = 4;
	p->b = 13;
	strcpy( p->c, "hello...." );

	printf( "a=%d, b=%d, c=%s\n", p->a, p->b, p->c );

	memoryPool_Release( h );
}

void test3() {
	poolHandle h = NULL;
	h = memoryPool_Create();
	if( !h ) {
		printf( "memoryPool_Create() err\n" );
		exit( 1 );
	}

	struct st {
		int a;
		long b;
		char* c;
	};

	struct st* p;
	if( !( p = ( struct st* )memoryPool_Alloc( h, sizeof( struct st ) ) ) ) {
		printf( "memoryPool_Alloc() err\n" );
		exit( 1 );
	}
	if( !( p->c = ( char* )memoryPool_Alloc( h, 10 ) ) ) {
		printf( "memoryPool_Alloc() err\n" );
		exit( 1 );
	}

	p->a = 4;
	p->b = 13;
	strcpy( p->c, "hello...." );

	printf( "a=%d, b=%d, c=%s\n", p->a, p->b, p->c );

	memoryPool_Release( h );
}

int main() {
	test1();
	test2();
	test3();
	test4();

	getchar();
	return 0;
}