read_sint <- function(handle) { 
    return(readBin(handle, "int", 1, size=4, signed = TRUE, endian = "big"));
}
read_uint <- function(handle) {   
    return(readBin(handle, "int", 1, size=4, signed = FALSE, endian = "big"));
}

read_real <- function(handle) {
    return(readBin(handle, "numeric", 1, size=4, endian = "big"));
}
 
################
  read_header_Ts.GHCN.CL <- function(handle) {
    len <- read_uint(handle);
    if( len < 9*4 ) {
            print("invalid file format");
         return(NA);
    }
    	vers <- read_sint(handle);  
    unk1 <- read_sint(handle);
    unk2 <- read_sint(handle);
    MTOT <- read_sint(handle);
    MTOT2 <- read_sint(handle);
    iyear1 <- read_sint(handle);
    inv1 <- read_sint(handle);
    inv2 <- read_sint(handle);
    MTOT_again <- read_sint(handle);
    title <- rawToChar(readBin(handle, "raw", len-9*4));
    if( read_uint(handle) != len ) {
         print("invalid file format");
        return(NA);
        }
        return(pairlist(vers=vers, unk1=unk1, unk2=unk2, MTOT=MTOT, MTOT2=MTOT2, iyear1=iyear1, inv1=inv1, inv2=inv2, MTOT_again=MTOT_again, title=title));
  }

  read_record_Ts.GHCN.CL <- function(handle) {
    len <- read_uint(handle);
    if( length(len) == 0 ) {
        # no more data
        return(NA);
    }
        if( len <= 44+16 ) {
        print("invalid file format");
        return(NA);
    }
        temp_data <- readBin(handle, "int", (len-44-16)/4, size=4, signed = TRUE, endian = "big");
    lato <- read_uint(handle);
    longo <- read_uint(handle);
    id <- read_uint(handle);
    ht <- read_uint(handle);
    name <- rawToChar(readBin(handle, "raw", 36));
    vers <- read_uint(handle);
        MTOT <- read_uint(handle);
        if( read_uint(handle) != len ) {
                print("invalid file format");
        return(NA);
    }
        return(pairlist(temp_data=temp_data, lato=lato, longo=longo, id=id, ht=ht, name=name, vers=vers, MTOT=MTOT));
  }



read_GISS_data_Ts.GHCN.CL <- function(handle) {


        header_data <- read_header_Ts.GHCN.CL(handle);
        records <- list();
        while(TRUE) {
                record <- read_record_Ts.GHCN.CL(handle);
                if( length(record) == 1 ) {
                        return(pairlist(header=header_data, records=records));
            } else {
                    records <- append(records, record);
            }
        }
}

#ftp://data.giss.nasa.gov/pub/gistemp/GISS_Obs_analysis/ARCHIVE/2008_05/binary_files/Ts.GHCN.CL.5
#handle <- file("Ts.GHCN.CL.1", "rb");
#data <- read_GISS_data_Ts.GHCN.CL(handle);
#close(handle);

#ftp://data.giss.nasa.gov/pub/gistemp/GISS_Obs_analysis/ARCHIVE/2008_05/binary_files/Ts.GHCN.CL.PA.5

######################################
 read_header_SBBX <- function(handle) {
    len <- read_uint(handle);
    if( len < 8*4 ) {
        print("invalid file format");
        return(NA);
    }
        Mnow <- read_sint(handle);
    unk1 <- read_sint(handle);
    unk2 <- read_sint(handle);
    MONM <- read_sint(handle);
    unk3 <- read_sint(handle);
    IYRBEG <- read_sint(handle);
    BAD <- read_sint(handle);
    unk4 <- read_sint(handle);
    title <- rawToChar(readBin(handle, "raw", len-8*4));
    if( read_uint(handle) != len ) {
        print("invalid file format");
        return(NA);
    }
        return(pairlist(Mnow=Mnow, unk1=unk1, unk2=unk2, MONM=MONM, unk3=unk3, IYRBEG=IYRBEG, BAD=BAD, unk4=unk4, title=title));
  }

  read_record_SBBX <- function(handle, Mnow) {
    len <- read_uint(handle);
    if( length(len) == 0 ) {
        # no more data
        return(NA);
    }
        if( len != (8+Mnow)*4 ) {
        print("invalid file format");
        return(NA);
    }
        Next <- read_sint(handle);
    LATS <- read_sint(handle);
    LATN <- read_sint(handle);
    LONW <- read_sint(handle);
    LONE <- read_sint(handle);
    NR1 <- read_sint(handle);
    NR2 <- read_sint(handle);
    DL <- read_sint(handle);
    temp_data <- readBin(handle, "numeric", Mnow, size=4, endian = "big");
    if( read_uint(handle) != len ) {
        print("invalid file format");
        return(NA);
    }
        return(pairlist(temp_data=temp_data, Next=Next, LATS=LATS, LATN=LATN, LONW=LONW, LONE=LONE, NR1=NR1, NR2=NR2, DL=DL));
  }
 


read_GISS_data_SBBX <- function(handle) {
    header_data <- read_header_SBBX(handle);
    Mnow = header_data$Mnow;
    records <- vector("pairlist", 1);
    num <- 1;
    while(TRUE) {
        record <- read_record_SBBX(handle, Mnow);
        if( length(record) == 1 ) {
            return(pairlist(header=header_data, records=records));
        } else {
                        records[[num]] = record;
                        num <- num+1;
            Mnow = record$Next;
        }
    }
}

 
#handle <- file("SBBX.SSTHadR2", "rb");
#data <- read_GISS_data_SBBX (handle);
#close(handle);
#print(data);

##ftp://data.giss.nasa.gov/pub/gistemp/GISS_Obs_analysis/ARCHIVE/2008_05/binary_files/SBBX1880.Ts.GHCN.CL.PA.250
##ftp://data.giss.nasa.gov/pub/gistemp/GISS_Obs_analysis/ARCHIVE/2008_05/binary_files/SBBX1880.Ts.GHCN.CL.PA.1200
##ftp://data.giss.nasa.gov/pub/gistemp/GISS_Obs_analysis/ARCHIVE/2008_05/binary_files/SBBX.HadR2
#################################

##MAKE GRID INFO
 make.grid.info=function (Data){ 
	f=function(X) unlist(X[2:9])
	grid.info=sapply(Data[[2]],f)
	grid.info=t(grid.info)
	grid.info=data.frame(grid.info)
		#the params LATS, LATN, LONW,LONE define the four parameters of the box
		#decimal values appear to be used
	grid.info[,2:5]=grid.info[,2:5]/100
		#order1=order(-grid.info$LATS,grid.info$LONW)
		#grid.info[order1,][1:100,]
	make.grid.info=grid.info
	make.grid.info
	}