reverse_io.rb in rexec-1.2.3

- old
+ new
@@ -1,70 +1,89 @@
+# Copyright (c) 2007, 2009, 2011 Samuel G. D. Williams. <http://www.oriontransfer.co.nz>
+# 
+# Permission is hereby granted, free of charge, to any person obtaining a copy
+# of this software and associated documentation files (the "Software"), to deal
+# in the Software without restriction, including without limitation the rights
+# to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+# copies of the Software, and to permit persons to whom the Software is
+# furnished to do so, subject to the following conditions:
+# 
+# The above copyright notice and this permission notice shall be included in
+# all copies or substantial portions of the Software.
+# 
+# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+# IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+# FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+# AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+# LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+# THE SOFTWARE.
 
 class File
-  # Seek to the end of the file
-  def seek_end
-    seek(0, IO::SEEK_END)
-  end
-  
-  # Read a chunk of data and then move the file pointer backwards.
-  #
-  # Calling this function multiple times will return new data and traverse the file backwards.
-  #
-  def read_reverse(length)
-    offset = tell
-    
-    if offset == 0
-      return nil
-    end
-    
-    start = [0, offset-length].max
-    
-    seek(start, IO::SEEK_SET)
-    
-    buf = read(offset-start)
-    
-    seek(start, IO::SEEK_SET)
-    
-    return buf
-  end
-  
-  REVERSE_BUFFER_SIZE = 128
+	# Seek to the end of the file
+	def seek_end
+		seek(0, IO::SEEK_END)
+	end
 
-  # This function is very similar to gets but it works in reverse.
-  #
-  # You can use it to efficiently read a file line by line backwards.
-  # 
-  # It returns nil when there are no more lines.
-  def reverse_gets(sep_string=$/)
-    end_pos = tell
-    
-    offset = nil
-    buf = ""
-    
-    while offset == nil
-      chunk = read_reverse(REVERSE_BUFFER_SIZE)
-      return (buf == "" ? nil : buf) if chunk == nil
-      
-      buf = chunk + buf
-      
-      offset = buf.rindex(sep_string)
-    end
-    
-    line = buf[offset...buf.size].sub(sep_string, "")
-    
-    seek((end_pos - buf.size) + offset, IO::SEEK_SET)
-    
-    return line
-  end
-  
-  # Similar to each_line but works in reverse. Don't forget to call
-  # seek_end before you start!
-  def reverse_each_line(sep_string=$/, &block)
-    line = reverse_gets(sep_string)
-    
-    while line != nil
-      yield line
-      
-      line = reverse_gets(sep_string)
-    end
-  end
+	# Read a chunk of data and then move the file pointer backwards.
+	#
+	# Calling this function multiple times will return new data and traverse the file backwards.
+	#
+	def read_reverse(length)
+		offset = tell
+
+		if offset == 0
+			return nil
+		end
+
+		start = [0, offset-length].max
+
+		seek(start, IO::SEEK_SET)
+
+		buf = read(offset-start)
+
+		seek(start, IO::SEEK_SET)
+
+		return buf
+	end
+
+	REVERSE_BUFFER_SIZE = 128
+
+	# This function is very similar to gets but it works in reverse.
+	#
+	# You can use it to efficiently read a file line by line backwards.
+	# 
+	# It returns nil when there are no more lines.
+	def reverse_gets(sep_string=$/)
+		end_pos = tell
+
+		offset = nil
+		buf = ""
+
+		while offset == nil
+			chunk = read_reverse(REVERSE_BUFFER_SIZE)
+			return (buf == "" ? nil : buf) if chunk == nil
+
+			buf = chunk + buf
+
+			offset = buf.rindex(sep_string)
+		end
+
+		line = buf[offset...buf.size].sub(sep_string, "")
+
+		seek((end_pos - buf.size) + offset, IO::SEEK_SET)
+
+		return line
+	end
+
+	# Similar to each_line but works in reverse. Don't forget to call
+	# seek_end before you start!
+	def reverse_each_line(sep_string=$/, &block)
+		line = reverse_gets(sep_string)
+
+		while line != nil
+			yield line
+
+			line = reverse_gets(sep_string)
+		end
+	end
 end