lib/dbf/table.rb in dbf-2.0.7 vs lib/dbf/table.rb in dbf-2.0.8

@@ -1,11 +1,14 @@
 module DBF
+  class FileNotFoundError < StandardError
+  end
 
   # DBF::Table is the primary interface to a single DBF file and provides
   # methods for enumerating and searching the records.
   class Table
     include Enumerable
+    include Schema
 
     DBF_HEADER_SIZE = 32
 
     VERSIONS = {
       "02" => "FoxBase",
@@ -57,15 +60,19 @@
     #
     # @param [String, StringIO] data Path to the dbf file or a StringIO object
     # @param [optional String, StringIO] memo Path to the memo file or a StringIO object
     # @param [optional String, Encoding] encoding Name of the encoding or an Encoding object
     def initialize(data, memo = nil, encoding = nil)
-      @data = open_data(data)
-      @data.rewind
-      @header = Header.new(@data.read(DBF_HEADER_SIZE), supports_encoding? || supports_iconv?)
-      @encoding = encoding || header.encoding
-      @memo = open_memo(data, memo)
+      begin
+        @data = open_data(data)
+        @data.rewind
+        @header = Header.new(@data.read(DBF_HEADER_SIZE), supports_encoding?)
+        @encoding = encoding || header.encoding
+        @memo = open_memo(data, memo)
+      rescue Errno::ENOENT => error
+        raise DBF::FileNotFoundError.new("file not found: #{data}")
+      end
     end
 
     # @return [TrueClass, FalseClass]
     def has_memo_file?
       !!@memo
@@ -106,11 +113,11 @@
     # the database.
     #
     # @param [Fixnum] index
     # @return [DBF::Record, NilClass]
     def record(index)
-      seek(index * header.record_length)
+      seek_to_record(index)
       if !deleted_record?
         DBF::Record.new(@data.read(header.record_length), columns, version, @memo)
       end
     end
 
@@ -135,41 +142,10 @@
     # @return [String]
     def version_description
       VERSIONS[version]
     end
 
-    # Generate an ActiveRecord::Schema
-    #
-    # xBase data types are converted to generic types as follows:
-    # - Number columns with no decimals are converted to :integer
-    # - Number columns with decimals are converted to :float
-    # - Date columns are converted to :datetime
-    # - Logical columns are converted to :boolean
-    # - Memo columns are converted to :text
-    # - Character columns are converted to :string and the :limit option is set
-    #   to the length of the character column
-    #
-    # Example:
-    #   create_table "mydata" do |t|
-    #     t.column :name, :string, :limit => 30
-    #     t.column :last_update, :datetime
-    #     t.column :is_active, :boolean
-    #     t.column :age, :integer
-    #     t.column :notes, :text
-    #   end
-    #
-    # @return [String]
-    def schema
-      s = "ActiveRecord::Schema.define do\n"
-      s << "  create_table \"#{File.basename(@data.path, ".*")}\" do |t|\n"
-      columns.each do |column|
-        s << "    t.column #{column.schema_definition}"
-      end
-      s << "  end\nend"
-      s
-    end
-
     # Dumps all records to a CSV file.  If no filename is given then CSV is
     # output to STDOUT.
     #
     # @param [optional String] path Defaults to STDOUT
     def to_csv(path = nil)
@@ -213,43 +189,63 @@
       when :first
         find_first(options)
       end
     end
 
-    # Retrieves column information from the database
+    # All columns
+    #
+    # @return [Array]
     def columns
-      @columns ||= begin
-        @data.seek(DBF_HEADER_SIZE)
-        columns = []
-        while !["\0", "\r"].include?(first_byte = @data.read(1))
-          column_data = first_byte + @data.read(31)
-          name, type, length, decimal = column_data.unpack('a10 x a x4 C2')
-          if length > 0
-            columns << column_class.new(name.strip, type, length, decimal, version, encoding)
-          end
-        end
-        columns
-      end
+      @columns ||= build_columns
     end
 
+    # Column names
+    #
+    # @return [String]
+    def column_names
+      columns.map { |column| column.name }
+    end
+
+    # Is string encoding supported?
+    # String encoding is always supported in Ruby 1.9+.
+    # Ruby 1.8.x requires that Ruby be compiled with iconv support.
     def supports_encoding?
-      String.new.respond_to?(:encoding)
+      supports_string_encoding? || supports_iconv?
     end
 
-    def supports_iconv?
+    # Does String support encoding?  Should be true in Ruby 1.9+
+    def supports_string_encoding?
+      ''.respond_to?(:encoding)
+    end
+
+    def supports_iconv? #nodoc
       require 'iconv'
       true
     rescue
       false
     end
 
-    def foxpro?
-      FOXPRO_VERSIONS.keys.include? version
+    private
+
+    def build_columns #nodoc
+      columns = []
+      @data.seek(DBF_HEADER_SIZE)
+      while !["\0", "\r"].include?(first_byte = @data.read(1))
+        column_data = first_byte + @data.read(DBF_HEADER_SIZE - 1)
+        name, type, length, decimal = column_data.unpack('a10 x a x4 C2')
+        if length > 0
+          columns << column_class.new(self, name, type, length, decimal)
+        end
+      end
+      columns
     end
 
-    private
 
+    def foxpro? #nodoc
+      FOXPRO_VERSIONS.keys.include? version
+    end
+
     def column_class #nodoc
       @column_class ||= foxpro? ? Column::Foxpro : Column::Dbase
     end
 
     def memo_class #nodoc
@@ -308,9 +304,13 @@
       @data.read(1).unpack('a') == ['*']
     end
 
     def seek(offset) #nodoc
       @data.seek header.header_length + offset
+    end
+
+    def seek_to_record(index) #nodoc
+      seek(index * header.record_length)
     end
 
     def csv_class #nodoc
       @csv_class ||= CSV.const_defined?(:Reader) ? FCSV : CSV
     end