Class: JavaClass::ClassFile::ConstantPool

Constants

CONSTANT_TYPE_TAGS = { CLASS_TAG = 7 => Constants::ConstantClass, FIELD_TAG = 9 => Constants::ConstantField, METHOD_TAG = 10 => Constants::ConstantMethod, INTERFACE_METHOD_TAG = 11 => Constants::ConstantInterfaceMethod, STRING_TAG = 8 => Constants::ConstantString, INT_TAG = 3 => Constants::ConstantInt, FLOAT_TAG = 4 => Constants::ConstantFloat, LONG_TAG = 5 => Constants::ConstantLong, DOUBLE_TAG = 6 => Constants::ConstantDouble, NAME_AND_TYPE_TAG = 12 => Constants::ConstantNameAndType, ASCIZ_TAG = 1 => Constants::ConstantAsciz, } Types of constants by their tag.

Attributes

size [R] Size of the whole constant pool in bytes.

Public Class methods

new(data, start=8)

Parse the constant pool from the bytes data beginning at position start (which is usually 8).

[Source]

# File lib/javaclass/classfile/constant_pool.rb, line 34
      def initialize(data, start=8)
        creator = PoolCreator.new(data, start)
        creator.create!
        
        @pool = creator.pool # cnt (Fixnum) => constant class
        @item_count = creator.item_count
        
        @size = @pool.values.inject(0) { |sum, constant| sum + constant.size } + 2
      end

Public Instance methods

[](index)

Return the index‘th pool item. index is the real index in the pool which may skip numbers.

[Source]

# File lib/javaclass/classfile/constant_pool.rb, line 51
      def[](index)
        check_index(index)
        @pool[index]
      end

class_item(index)

Return the constant class from index‘th pool item.

[Source]

# File lib/javaclass/classfile/constant_pool.rb, line 84
      def class_item(index)
        if self[index] && !self[index].const_class?
          raise ClassFormatError, "inconsistent constant pool entry #{index} for class, should be Constant Class"
        end
        self[index]
      end

dump()

Return a debug output of the whole pool.

[Source]

# File lib/javaclass/classfile/constant_pool.rb, line 79
      def dump
        ["  Constant pool:"] + @pool.keys.sort.collect { |k| "const ##{k} = #{self[k].dump}"}
      end

field_item(index)

Return the constant field from index‘th pool item.

[Source]

# File lib/javaclass/classfile/constant_pool.rb, line 92
      def field_item(index)
        if self[index] && !self[index].const_field?
          raise ClassFormatError, "inconsistent constant pool entry #{index} for field, should be Constant Field"
        end
        self[index]
      end

find(*tags)

Return an array of all constants of the given tags types.

[Source]

# File lib/javaclass/classfile/constant_pool.rb, line 69
      def find(*tags)
        items.find_all { |item| tags.include? item.tag }
      end

item_count()

Return the number of pool items. This number might be larger than items available, because long and double constants take two slots.

[Source]

# File lib/javaclass/classfile/constant_pool.rb, line 46
      def item_count
        @item_count - 1
      end

items()

Return an array of the ordered list of constants.

[Source]

# File lib/javaclass/classfile/constant_pool.rb, line 64
      def items
        @pool.keys.sort.collect { |k| self[k] }
      end

method_item(index)

Return the constant method from index‘th pool item.

[Source]

# File lib/javaclass/classfile/constant_pool.rb, line 100
      def method_item(index)
        if self[index] && !self[index].const_method?
          raise ClassFormatError, "inconsistent constant pool entry #{index} for method, should be Constant Method"
        end
        self[index]
      end

strings()

Return all string constants.

[Source]

# File lib/javaclass/classfile/constant_pool.rb, line 74
      def strings
        find(STRING_TAG)
      end

Methods

Constants

Attributes

Public Class methods

Public Instance methods