/*----------------------------------------------------------
  [jaxamodis2img.c]             A.Kondoh 2005
  JAXA/MODISのSST(CHLA)データを抽出するプログラム
  ２バイト(signed short)をIntel用に変換
  フラグ：雲=0(0)、陸域=-1(65535)、領域外=-2(65534)
  ()内はunsigned charの場合であるが、40℃の場合でも
  DNは5000であるので、signed charで良いと思われる
  ----------------------------------------------------------*/

#include        <stdio.h>
#include        <stdlib.h>
#include        <fcntl.h>
#include        <sys\types.h>
#include        <sys\stat.h>
#include        <io.h>
#include        <string.h>
#include        <memory.h>

/* 適当な大きな数字 */
#define         MAX_BUFFER_SIZE         10000

/* バイト順を変更しながら処理するのでunsigned charで良い */
unsigned char   buffer[MAX_BUFFER_SIZE];

void    main(argc,argv)
int     argc;
char    *argv[];
{
        int             number_of_pixels;
        int             number_of_lines;
        int             buffer_size;
        int             fi,fo;
        int             i,j,pixel2,line2;
        double          ul_lat,ul_lon;  /* 左上経度、左上緯度 */
        double          dx;             /* 緯経度刻み */
        double          slope,offset;   /* slope, offset */
        unsigned char   dummy;
        int             year,month,day,utc_hour,utc_min;

        if(argc!=3){
                printf("Usage: jaxamodis2img [input file name] [output file name]\n");
                exit(-1);
        }

/* ファイル名からピクセル、ライン数ほかを取得 */

        sscanf(&argv[1][5],"%2d",&year);
        sscanf(&argv[1][7],"%2d",&month);
        sscanf(&argv[1][9],"%2d",&day);
        sscanf(&argv[1][11],"%2d",&utc_hour);
        sscanf(&argv[1][13],"%2d",&utc_min);

        sscanf(&argv[1][25],"%5d",&number_of_pixels);
        sscanf(&argv[1][31],"%5d",&number_of_lines);

        buffer_size=number_of_pixels*sizeof(short);
        if(buffer_size>MAX_BUFFER_SIZE){
                fprintf(stderr,"Change MAX_BUFFER_SIZE.\n");
                exit(-1);
        }

        if((fi=open(argv[1],O_RDONLY | O_BINARY))==-1){
                fprintf(stderr,"Can't open %s.\n",argv[1]);
                exit(-1);
        }

        if((fo=open(argv[2],O_CREAT | O_TRUNC | O_RDWR | O_BINARY, S_IREAD | S_IWRITE))==-1){
                fprintf(stderr,"Can't open %s.\n",argv[2]);
        }

/* ヘッダー情報読み取り */

        read(fi,buffer,buffer_size);

        sscanf(buffer,"%d %d %lf %lf %lf %lf %lf"
                     ,&pixel2,&line2,&ul_lon,&ul_lat,&dx,&slope,&offset);

        printf("input pixel line year month day utc_hour utc_min ul_lon ul_lat int slope offset\n");

        printf("%s ",argv[1]);

        printf("%6d ",pixel2);
                if(pixel2!=number_of_pixels){
                        fprintf(stderr,"Error in number_of_pixels.\n");
                        exit(-1);
                }
        printf("%6d ",line2);
                if(line2!=number_of_lines){
                        fprintf(stderr,"Error in number_of_lines.\n");
                        exit(-1);
                }

        printf("%2d ",year);
        printf("%2d ",month);
        printf("%2d ",day);
        printf("%2d ",utc_hour);
        printf("%2d ",utc_min);

        printf("%8.2lf ",ul_lon);
        printf("%8.2lf ",ul_lat);
        printf("%8.2lf ",dx);
        printf("%9.4lf ",slope);
        printf("%9.4lf\n",offset);

/* 画素情報抽出 */

        for(i=0;i<number_of_lines;i++){
                if(!(i%300))    fprintf(stderr,"*");

                if( (read(fi,buffer,buffer_size))==-1){
                        fprintf(stderr,"read err\n");
                        exit(-1);
                }

             /* byte change : Motorola->Intel */

                for(j=0;j<number_of_pixels*2;j+=2){
                        dummy=buffer[j];
                        buffer[j]=buffer[j+1];
                        buffer[j+1]=dummy;
                }

                if( (write(fo,buffer,buffer_size))==-1){
                        fprintf(stderr,"write err\n");
                        exit(-1);
                }

        }/* next line */

}/* end of main */