Fresh start

1 files changed, 75 insertions, 0 deletions

diff --git a/jni/ruby/lib/rubygems/text.rb b/jni/ruby/lib/rubygems/text.rb
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+++ b/jni/ruby/lib/rubygems/text.rb
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+require 'rubygems'
+
+##
+# A collection of text-wrangling methods
+
+module Gem::Text
+
+  ##
+  # Wraps +text+ to +wrap+ characters and optionally indents by +indent+
+  # characters
+
+  def format_text(text, wrap, indent=0)
+    result = []
+    work = text.dup
+
+    while work.length > wrap do
+      if work =~ /^(.{0,#{wrap}})[ \n]/ then
+        result << $1.rstrip
+        work.slice!(0, $&.length)
+      else
+        result << work.slice!(0, wrap)
+      end
+    end
+
+    result << work if work.length.nonzero?
+    result.join("\n").gsub(/^/, " " * indent)
+  end
+
+  def min3 a, b, c # :nodoc:
+    if a < b && a < c then
+      a
+    elsif b < c then
+      b
+    else
+      c
+    end
+  end
+
+  # This code is based directly on the Text gem implementation
+  # Returns a value representing the "cost" of transforming str1 into str2
+  def levenshtein_distance str1, str2
+    s = str1
+    t = str2
+    n = s.length
+    m = t.length
+    max = n/2
+
+    return m if (0 == n)
+    return n if (0 == m)
+    return n if (n - m).abs > max
+
+    d = (0..m).to_a
+    x = nil
+
+    str1.each_char.each_with_index do |char1,i|
+      e = i+1
+
+      str2.each_char.each_with_index do |char2,j|
+        cost = (char1 == char2) ? 0 : 1
+        x = min3(
+             d[j+1] + 1, # insertion
+             e + 1,      # deletion
+             d[j] + cost # substitution
+            )
+        d[j] = e
+        e = x
+      end
+
+      d[m] = x
+    end
+
+    return x
+  end
+end
+