allocate multiple dimensional array in 1D. Support generic types

mat.h

/*
* mat.h
* allocate multiple dimensional array into 1D
* using generic function macro
* with new/free/get functions
* created by Jingtao Liu
* 01/22/2013
*/
#ifndef _MATRIX_H
#define _MATRIX_H
#include <stdlib.h>
#include <stdio.h>

#define MD_TYPE_DEFINE(name, data_t )  \
	typedef struct {	\
		int  dims;	\
		int  *dim_define;\
		int *pre; 	\
		data_t *data;	\
		int  size ;	\
	}matrix_##name##_t ;

#define MD_METHOD_DEFINE(name, data_t)	\
	void matrix_##name##_pre_compute(matrix_##name##_t *mat)\
	{\
		int i,t;\
		for(i=0;i<mat->dims;i++) mat->pre[i]=1;\
		for(i=1,t=1;i<mat->dims; i++){\
			t*=mat->dim_define[i-1];\
			mat->pre[i]=t;\
		}\
	}\
	matrix_##name##_t * matrix_##name##_new( int  dims, int  *dim_define)\
	{\
		int  i, size=1;\
		for(i=0;  i<dims; i++)\
			size*=dim_define[i];\
		matrix_##name##_t *ret=malloc(  sizeof(matrix_##name##_t));\
		ret->size=size; \
		ret->dims=dims;\
		ret->data=calloc(ret->size, sizeof(data_t) );\
		ret->pre=calloc( ret->dims, sizeof(int));\
		ret->dim_define=malloc(sizeof(int )*dims ) ;\
		for(i=0;i<dims;i++)\
			ret->dim_define[i]=dim_define[i] ;\
		matrix_##name##_pre_compute(ret);\
		return ret;\
	}\
	void matrix_##name##_free (matrix_##name##_t * mat)\
	{\
	  if (mat)\
	    {\
	      if (mat->data)\
		free (mat->data);\
	      if (mat->dim_define)\
		free (mat->dim_define);\
	      if (mat->pre)\
		free (mat->pre);\
	      free (mat);\
	    }\
	}\
	inline int matrix_##name##_offset(matrix_##name##_t *mat, int *target) \
	{\
		int i, index;\
		for(i=0,index=0;i<mat->dims;i++)\
			index+=(target[i]*mat->pre[i]);\
		return index;\
	}\
	data_t *matrix_##name##_get(matrix_##name##_t *mat, int *target )\
	{\
		int offset=matrix_##name##_offset(mat, target);\
		if(offset >=0 && offset<mat->size )     \
			return mat->data+offset;\
		else\
			return NULL;\
	}
#define matrix_new(name,dims, dim) matrix_##name##_new(dims, dim )
#define matrix_free(name, m) matrix_##name##_free( m )
#define matrix_get(name, m, target) matrix_##name##_get( m, target )
#define matrix_offset(name, m, target) matrix_##name##_offset( m, target )


#endif //_MATRIX_H

#ifdef _MATRIX_MAIN
//compile : 
//cat mat.h | gcc -xc  -D_MATRIX_MAIN  -
//usage
MD_TYPE_DEFINE(int, int ) ;
MD_METHOD_DEFINE(int, int) 
int main(){
        int dims=1;
        int d[1]={10 };
        int target[1]={7};
        int *dim=d;
        matrix_int_t *m=matrix_new( int,dims, dim);
        *matrix_get(int, m,  target)=17441;
        printf("index %d, value %d\n", matrix_offset(int,m,  target),   *matrix_get(int, m,  target) );
        matrix_free(int,m);

}
#endif //_MATRIX_MAIN