R/ReadHeader.R

In leachth/ReadEKRaw_updated:

#function [header, frequencies] = readEKRaw_ReadHeader(fid)
#readEKRaw_ReadHeader  Read EK/ES raw data file header
#   [header, frequencies] = readEKRaw_ReadHeader(fid) returns a structure
#       containing file header and transceiver configuration data.
#
#   REQUIRED INPUT:
#               fid:    file handle id
#
#   OPTIONAL PARAMETERS:    None
#
#   OUTPUT:
#       Output is a data structure containing the header and transceiver
#       configuration data.
#
#   REQUIRES:   None
#

#   Rick Towler
#   NOAA Alaska Fisheries Science Center
#   Midwater Assesment and Conservation Engineering Group
#   rick.towler@noaa.gov

#

#  read configuration datagram (file header)
#fread(fid, 1, 'int32', 'l');
#[dgType, dgTime] = readEKRaw_ReadDgHeader(fid, 0);

#configheader = readEKRaw_ReadConfigHeader(fid);
#configheader.time = dgTime;

#  extract individual xcvr configurations and store list of frequencies
#frequencies = zeros(1, configheader.transceivercount);
#for i = 1:configheader.transceivercount
#   configXcvr(i) = readEKRaw_ReadTransceiverConfig(fid);
#    frequencies(i) = configXcvr(i).frequency;
#end

# create the configuration structure - store header and xcvr configs
# header = struct('header',configheader,'transceiver',configXcvr);

#fread(fid, 1, 'int32', 'l');


# R code
ReadHeader = function(fid){
	#  read configuration datagram (file header)
			datagram.header = readBin(
						con  	= fid,
						what 	= 'integer',
						n    	= 1,
						size 	= 4,
						signed  = TRUE,
						endian 	= "little")

# run function ReadDgHeader - returns list dg with dgType and dgTime as elements
			dg = ReadDgHeader(fid)

# run function ReadConfigHeader - returns list configheader
			configheader = ReadConfigHeader(fid)

	# add $time to configheader list
			configheader$time = dg$dgTime

# extract frequencies into list
configXcvr  = list()
frequencies = NULL  # create empty vector
for(i in 1:configheader$transceivercount){
		configXcvr[[i]] = ReadTransceiverConfig(fid)
		frequencies[i] = configXcvr[[i]]$frequency
}
header = list(header = configheader, transceiver = configXcvr)

datagram.length2 = readBin(
    con  	= fid,
    what 	= 'integer',
    n    	= 1,
    size 	= 4,
    signed  = TRUE,
    endian 	= "little")

return(header)

}