Class: CAStruct::Builder

Inherits:
Object show all
Defined in:
lib/carray/struct.rb

Overview

Struct Builder Class

Defined Under Namespace

Classes: Member

Constant Summary collapse

ALIGN_TABLE = 
{
  CA_FIXLEN   => CA_ALIGN_FIXLEN,
  CA_BOOLEAN  => CA_ALIGN_INT8,
  CA_INT8     => CA_ALIGN_INT8,
  CA_UINT8    => CA_ALIGN_INT8,
  CA_INT16    => CA_ALIGN_INT16,
  CA_UINT16   => CA_ALIGN_INT16,
  CA_INT32    => CA_ALIGN_INT32,
  CA_UINT32   => CA_ALIGN_INT32,
  CA_INT64    => CA_ALIGN_INT64,
  CA_UINT64   => CA_ALIGN_INT64,
  CA_FLOAT32  => CA_ALIGN_FLOAT32,
  CA_FLOAT64  => CA_ALIGN_FLOAT64,
  CA_CMPLX64  => CA_ALIGN_FLOAT32,
  CA_CMPLX128 => CA_ALIGN_FLOAT64,
}
CARRAY_METHODS = 
CArray.instance_methods.map{|m| m.intern }

Instance Method Summary collapse

Constructor Details

#initialize(type, opt = {}) ⇒ Builder 



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# File 'lib/carray/struct.rb', line 336

def initialize (type, opt = {})
  if not opt[:pack].nil? and not opt[:pack].is_a?(Integer)
    raise "invalid alignment given '#{align}'"
  end
  @type      = type       ### :struct or :union
  @align     = opt[:pack] ### nil for alignment, int for pack(n)
  @members   = []         ### array of CArray::Struct::Builder::Member
  @offset    = 0          ### offset of each member and size of struct
  @align_max = 1          ### maximum of alignment among members
  @size      = opt[:size] ### user defined struct size
end

Instance Method Details

#array(*args) ⇒ Object 



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# File 'lib/carray/struct.rb', line 508

def array (*args)
  opt = args.last.is_a?(Hash) ? args.pop : {}   
  if not opt[:type] or not opt[:type].kind_of?(CArray)
    raise "type is not given for array member of struct"
  end
  args.each do |arg|
    member(opt[:type], arg)
  end
end

#define(&block) ⇒ Object 



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# File 'lib/carray/struct.rb', line 348

def define (&block)
  # ---
  case block.arity
  when 1
    block.call(self)      ### struct/union definition block
  when -1, 0
    instance_exec(&block) ### struct/union definition block
  else
    raise "invalid # of block parameters"
  end
  # ---
  case @type
  when :struct
    klass = Class.new(CAStruct)
  when :union
    klass = Class.new(CAUnion)
  end
  # ---
  if @align.nil?
    @offset = alignment(@offset, :align_max)
  end
  if @size
    if @size < @offset
      raise RuntimeError, "struct size exceeds the fixlen size"
    end
    @offset = @size
  end
  klass.const_set(:DATA_SIZE, @offset)   ### required element as data class
  # ---
  table = Hash.new
  names = []
  @members.each do |mem|
    name   = mem.name
    type   = mem.type
    offset = mem.offset
    bytes  = mem.bytes
    if bytes
      table[name] = [offset, type, {:bytes=>bytes}]
    else
      table[name] = [offset, type]
    end
    names.push(name)
  end
  klass.const_set(:MEMBER_TABLE, table)   ### required element as data class
  klass.const_set(:MEMBERS, names)
  # ---
  klass.module_eval {
    names.each do |name|
      define_method(name) {
        return self[name]
      }
      define_method("#{name}=") { |val|
        return self[name] = val
      }
    end
  }
  # ---
  return klass
end

#member(data_type, id = nil, opt = {}) ⇒ Object 



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# File 'lib/carray/struct.rb', line 440

def member (data_type, id = nil, opt = {})
  opt = opt.clone
  if id
    id = id.to_s
  else
    id = "#{@members.size}"
  end
  case @type
  when :struct                           ### struct
    case @align
    when nil                             ### -- aligned
      @offset = alignment(@offset, data_type, opt)
      opt[:offset] = @offset
    else                                 ### -- packed
      if opt[:offset]                    ### ---- explicit offset
        @offset = pack(opt[:offset], @align, opt)
      else
        opt[:offset] = @offset           ### ---- auto offset
      end
    end
    mem = Member.new(id, data_type, opt)
    @members.push(mem)
    @offset += mem.byte_length
  when :union                            ### union
    alignment(0, data_type, opt)
    opt[:offset] = 0
    mem = Member.new(id, data_type, opt)
    @members.push(mem)
    if mem.byte_length > @offset
      @offset = mem.byte_length
    end
  end
end

#struct(*args, &block) ⇒ Object

method for nested struct



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# File 'lib/carray/struct.rb', line 475

def struct (*args, &block)
  opt = args.last.is_a?(Hash) ? args.pop : {}   
  if block
    opt = {:pack => @align}.update(opt)
    st = self.class.new(:struct, opt).define(&block)
  elsif opt[:type] and opt[:type] <= CAStruct
    st = opt[:type]
  else
    raise "type is not given for struct member of struct"
  end
  args.each do |arg|
    member(st, arg)
  end
  return st
end

#union(*args, &block) ⇒ Object

method for nested union



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# File 'lib/carray/struct.rb', line 492

def union (*args, &block)
  opt = args.last.is_a?(Hash) ? args.pop : {}   
  if block
    opt = {:pack => @align}.update(opt)
    st = self.class.new(:union, opt).define(&block)
  elsif opt[:type] and opt[:type] <= CAStruct
    st = opt[:type]
  else
    raise "type is not given for union member of struct"
  end
  args.each do |arg|
    member(st, arg)
  end
  return st
end