/* purpose: conversion of binary data with little-endian to ASCII

    Sep. 8, 2006 by Maosheng Zhao */

 /* I also accounts for the possible different CPU on different platforms,

    and therefore, it should work on different machines without problem */

 #include<stdio.h>

 #define COLS 7200

 #define ROWS 3600

 #define DATA_TYPE unsigned short

 /*$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$*/

 #define IN_FILE_NAME  "Npp_0.05deg_mean.int16"

 #define OUT_FILE_NAME "Npp_0.05deg_mean.ASCII2"

 /*$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$$*/

 int main()

 {

     /* definiation of variables will be used */

     FILE *in_f, *out_f;

     static DATA_TYPE data_in[ROWS][COLS];

     int i,j;

     /* the follow definition is for determination the type of CPU */

     int  is_big_endian=0;

     short one=1;

     char *cp;

     /* define a buffer pointer to swap bytes if it is big-endian CPU */

     char temp_char[sizeof(DATA_TYPE)];

     DATA_TYPE *buffer_data; 

     int m;

     /*################################################################*/

     /* main program starts */

     /* open the data file and read all the data */

     in_f = fopen(IN_FILE_NAME,"rb");

     if(in_f == NULL)

     {

 	printf("cannot open %s, exit...\n",IN_FILE_NAME);

 	exit(0);

     }

     else  /* reading the data */

     {

 	/* tell the type of CPU */

 	cp = (char*)&one;

 	if(*cp == 0)

 	   is_big_endian = 1;  /* yes, this is a big-endian CPU */

 	else

 	   is_big_endian = 0;  /* this is a little-endian CPU */

 	if(is_big_endian == 0)

 	{

 	   printf("This is a little-endian CPU, no need to swap bytes\n");

 	   printf("reading data now, please waiting for...\n");

 	   fread(data_in,sizeof(DATA_TYPE),COLS*ROWS,in_f);

 	}

 	else

 	{

 	   printf("This is a big-endian CPU, which needs to swap bytes\n");

 	   printf("reading data now, please waiting for...\n");

 	   for(i=0;i<ROWS;i++)

 		for(j=0;j<COLS;j++)

 		{

 	   	   for(m=0;m<sizeof(DATA_TYPE);m++)

 			fread(&temp_char[sizeof(DATA_TYPE)-1-m],1,1,in_f);

 		   /* swap the byte order */

 		   buffer_data = (DATA_TYPE*)temp_char;

 		   data_in[i][j] = *buffer_data;

 		} /* end of nested loops for i and j */

 	}

     }

     /* close the input file */

     fclose(in_f);

     /* write the ASCII to a new file */

     out_f = fopen(OUT_FILE_NAME,"w");

     printf("Please waiting for writing data to %s\n",OUT_FILE_NAME);

     for(i=0;i<ROWS;i++)

 	for(j=0;j<COLS;j++)

 	    fprintf(out_f,"%6d\n",data_in[i][j]);

     fclose(out_f);

     printf("Finished conversion of binary to ASCII\n");

     return(0);

 }