Class: String

Inherits:
Object
  • Object
show all
Defined in:
lib/capistrano/gitflow_version/natcmp.rb

Overview

natcmp.rb

Natural order comparison of two strings e.g. “my_prog_v1.1.0” < “my_prog_v1.2.0” < “my_prog_v1.10.0” which does not follow alphabetically

Based on Martin Pool’s “Natural Order String Comparison” originally written in C sourcefrog.net/projects/natsort/

This implementation is Copyright © 2003 by Alan Davies <cs96and_AT_yahoo_DOT_co_DOT_uk>

This software is provided ‘as-is’, without any express or implied warranty. In no event will the authors be held liable for any damages arising from the use of this software.

Permission is granted to anyone to use this software for any purpose, including commercial applications, and to alter it and redistribute it freely, subject to the following restrictions:

  1. The origin of this software must not be misrepresented; you must not claim that you wrote the original software. If you use this software in a product, an acknowledgment in the product documentation would be appreciated but is not required.

  2. Altered source versions must be plainly marked as such, and must not be misrepresented as being the original software.

  3. This notice may not be removed or altered from any source distribution.

Class Method Summary collapse

Class Method Details

.natcmp(str1, str2, caseInsensitive = false) ⇒ Object

‘Natural order’ comparison of two strings



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# File 'lib/capistrano/gitflow_version/natcmp.rb', line 32

def String.natcmp(str1, str2, caseInsensitive=false)
	str1, str2 = str1.dup, str2.dup
	compareExpression = /^(\D*)(\d*)(.*)$/

	if caseInsensitive
		str1.downcase!
		str2.downcase!
	end

	# Remove all whitespace
	str1.gsub!(/\s*/, '')
	str2.gsub!(/\s*/, '')

	while (str1.length > 0) or (str2.length > 0) do
		# Extract non-digits, digits and rest of string
		str1 =~ compareExpression
		chars1, num1, str1 = $1.dup, $2.dup, $3.dup

		str2 =~ compareExpression
		chars2, num2, str2 = $1.dup, $2.dup, $3.dup

		# Compare the non-digits
		case (chars1 <=> chars2)
			when 0 # Non-digits are the same, compare the digits...
				# If either number begins with a zero, then compare alphabetically,
				# otherwise compare numerically
				if (num1[0] != 48) and (num2[0] != 48)
					num1, num2 = num1.to_i, num2.to_i
				end

				case (num1 <=> num2)
					when -1 then return -1
					when 1 then return 1
				end
			when -1 then return -1
			when 1 then return 1
		end # case

	end # while

	# Strings are naturally equal
	return 0
end