Class: NCFileWriter

Inherits:
Object
  • Object
show all
Includes:
NC
Defined in:
lib/io/netcdf.rb,
lib/io/netcdf.rb

Defined Under Namespace

Classes: Dim, Var

Constant Summary collapse

TYPEMAP = 
{
  "char" => NC_CHAR,
  "byte" => NC_BYTE,
  "short" => NC_SHORT,
  "int" => NC_INT,
  "float" => NC_FLOAT,
  "double" => NC_DOUBLE,
}

Instance Attribute Summary collapse

Class Method Summary collapse

Instance Method Summary collapse

Methods included from NC

nc_decode, nc_put_att_simple, nc_put_var_all

Constructor Details

#initialize(file, mode = 0, template: nil, compression: 0) ⇒ NCFileWriter

Returns a new instance of NCFileWriter.



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# File 'lib/io/netcdf.rb', line 649

def initialize (file, mode = 0, template: nil, compression: 0)
  @dims     = []
  @name2dim = {}
  @vars     = []
  @name2var = {}
  @compression = compression
  @attributes = nil      
  if template.nil?
    if compression > 0
      @file_id  = nc_create(file, mode|NC_NETCDF4)
    else
      @file_id  = nc_create(file, mode)
    end
  else
    IO.popen("ncgen -o #{file}", "w") { |io|
      io.write(template)
    }
    if compression > 0
      @file_id  = nc_open(file, mode|NC_WRITE|NC_SHARE|NC_NETCDF4)
    else
      @file_id  = nc_open(file, mode|NC_WRITE|NC_SHARE)
    end
    NCFile.open(file) {|nc|
      define nc.definition, define_mode: false
    }
  end
end

Instance Attribute Details

#file_id ⇒ Object (readonly)

Returns the value of attribute file_id.



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# File 'lib/io/netcdf.rb', line 677

def file_id
  @file_id
end

Class Method Details

.convert_attribute_value(value) ⇒ Object 



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# File 'lib/io/netcdf.rb', line 731

def self.convert_attribute_value (value)
  case value
  when Hash
    type, value = *value.first
    case type
    when "char"
      value = CA_UINT8(value)
    when "byte"
      value = CA_BYTE(value)
    when "short"
      value = CA_SHORT(value)
    when "int"
      value = CA_INT(value)
    when "float"
      value = CA_FLOAT(value)
    when "double"
      value = CA_DOUBLE(value)
    end
  end
  return value
end

.scaled_integer(type, value) ⇒ Object 



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# File 'lib/io/netcdf.rb', line 807

def self.scaled_integer (type, value)
  min, max = value.min, value.max
  case type
  when :short
    short_max = (0x7fff-1).to_f
    fillvalue = CA_SHORT(0x7fff+1)[0]
    scale_factor = (max - min)/short_max
    add_offset = min + short_max*scale_factor
    packed = ((value - add_offset)/scale_factor).short
  when :int
    int_max = (0x7fffffff-1).to_f
    fillvalue = CA_INT(0x7fffffff+1)[0]
    scale_factor = (max - min)/int_max
    add_offset = min + int_max*scale_factor
    packed = ((value - add_offset)/scale_factor).int
  else
    raise
  end
  packed.attribute["scale_factor"] = scale_factor
  packed.attribute["add_offset"] = add_offset
  if value.has_mask?
    packed[:is_masked] = fillvalue
    packed.attribute["_FillValue"] = fillvalue
  end
  return packed
end

Instance Method Details

#[](name) ⇒ Object 



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# File 'lib/io/netcdf.rb', line 791

def [] (name)
  return @name2var[name]
end

#[]=(name, value) ⇒ Object 



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# File 'lib/io/netcdf.rb', line 795

def []= (name, value)
  return @name2var[name].put(value)
end

#check_definition(definition) ⇒ Object 



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# File 'lib/io/netcdf.rb', line 691

def check_definition (definition)
  if definition.has_key?("dimensions")
    dim_keys = definition["dimensions"].keys
  else
    raise "NetCDF definition shoud have 'dimensions' entry"
  end
  if definition.has_key?("variables")
    definition["variables"].each do |name, var_def|
      unless var_def.has_key?("type")
        warn "NetCDF Variable '#{name}' does not have 'type' entry in definition"
      else
        unless ["char","byte","short","int","float","double"].include?(var_def["type"])
          raise "invalid type of NetCDF Variable '#{name}'"
        end          
      end 
      unless var_def.has_key?("dim") 
        warn "NetCDF Variable '#{name}' does not have 'dim' entry in definition"
      else
        unless var_def["dim"].is_a?(Array)
          raise "'dim' of NetCDF Variable '#{name}' should be an Array"
        else
          var_def["dim"].each do |dim|
            unless dim_keys.include?(dim)
              raise "invalid dimension '#{dim}' for NetCDF Variable '#{name}'"
            end
          end
        end
      end 
      var_def.each do |k, v|
        case v
        when Hash
          if v.size > 1 or not ["byte","short","int","float","double"].include?(v.keys[0])
            raise "invalid specification in attribute '#{k}' for NetCDF Variable '#{name}'"
          end
        end
      end
    end
  end
end

#close ⇒ Object 



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# File 'lib/io/netcdf.rb', line 799

def close
  nc_close(@file_id)
end

#define(definition, define_mode: true) ⇒ Object 



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# File 'lib/io/netcdf.rb', line 753

def define (definition, define_mode: true)
  definition = normalize_definition(definition)
  check_definition(definition)
  definition["dimensions"].each do |name, len|
    dim = Dim.new(self, name, len.to_i, define_mode)
    @dims.push dim
    @name2dim[name] = dim
  end
  definition["variables"].each do |name, info|
    var = Var.new(self, name, info, @compression, define_mode)
    @vars.push var
    @name2var[name] = var
  end
  if definition.has_key?("attributes")
    @attributes = definition["attributes"]
    if define_mode
      @attributes.each do |name, value|
        value = NCFileWriter.convert_attribute_value(value)
        begin
          nc_put_att(@file_id, NC_GLOBAL, name, value)
        rescue => e
          raise(e.class, e.error_message + " {#{name}: #{value}}")
        end
      end
    end
    @attributes.freeze
  else
    @attributes = {}.freeze
  end
  if define_mode
    nc_enddef(@file_id)
  end
end

#dim(name) ⇒ Object 



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# File 'lib/io/netcdf.rb', line 787

def dim (name)
  return @name2dim[name]
end

#normalize_definition(definition) ⇒ Object

key of Hash in definition should be String



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# File 'lib/io/netcdf.rb', line 680

def normalize_definition (definition)
  out = {}
  definition.each do |key, value|
    if value.is_a?(Hash)
      value = normalize_definition(value)
    end
    out[key.to_s] = value
  end
  return out
end