增加了 ruby 版本的 内存查找

binding/ruby/ip_2_region.rb

@@ -0,0 +1,76 @@
+class Ip2Region
+  INDEX_BLOCK_LENGTH = 12
+  TOTAL_HEADER_LENGTH = 8192
+  attr_accessor :f, :headerSip, :headerPtr, :headerLen, :indexSPtr, :indexLPtr, :indexCount, :dbBinStr
+
+  def initialize(dbfile = "../../data/ip2region.db")
+    initDatabase(dbfile)
+    true
+  end
+
+  def initDatabase(dbfile = "ip2region.db")
+    @dbBinStr = File.open(dbfile, 'rb').read
+
+    @indexSPtr = getLong(@dbBinStr, 0)
+    @indexLPtr = getLong(@dbBinStr, 4)
+    @indexCount = ((indexLPtr - indexSPtr) / INDEX_BLOCK_LENGTH).to_i + 1
+    # puts "#{@indexSPtr} #{@indexLPtr} #{@indexCount}"
+  end
+
+  def memorySearch(ip)
+    ip = ip2long(ip)
+
+    l, h, dataPtr = 0, indexCount , 0
+    # print(l,h,dataPtr)
+    while l <= h
+      m  = (l + h) >> 1
+      p = m * INDEX_BLOCK_LENGTH + indexSPtr
+      # puts "m = #{m}, p = #{p}"
+      sip = getLong(@dbBinStr, p)
+      # puts "sip =  #{sip}"
+            
+      if ip < sip
+        h = m - 1
+      else
+        eip = getLong(@dbBinStr, p + 4)
+        if ip > eip
+          l = m + 1
+        else
+          dataPtr = getLong(@dbBinStr, p + 8)
+          break
+        end
+      end
+    end
+
+    if dataPtr == 0
+      return nil
+    end
+
+    returnData(dataPtr)
+  end
+
+  def returnData(dataPtr)
+    dataLen = (dataPtr >> 24) & 0xFF
+    dataPtr = dataPtr & 0x00FFFFFF
+    data = @dbBinStr[dataPtr, dataLen]
+    # @dbBinStr.seek(dataPtr)
+    # data = @dbBinStr.read(dataLen)
+    
+    return {
+      :city_id => getLong(data, 0),
+      :region => data[4..-1].force_encoding("utf-8")
+    }
+  end
+
+  def getLong(b, offset)
+    if (b[offset..offset+3] || []).length == 4
+      # puts "unpack = #{b[offset..offset+3].unpack('I')}"
+      return b[offset..offset+3].unpack('I')[0].to_i
+    end
+    0
+  end
+
+  def ip2long(ip)
+    ip.split('.').inject(0) {|s,x| s*256 + x.to_i}
+  end
+end

binding/ruby/ip_2_region_test.rb

@@ -0,0 +1,15 @@
+# 只实现了 memory 版本的， 其他的靠兄弟们实现了
+
+require_relative 'ip_2_region'
+
+s = Ip2Region.new
+
+(1..235).each do |i|
+  ip = "#{i}.#{i}.#{i}.#{i}"
+  answer = s.memorySearch ip
+  puts "#{ip} , answer = #{answer}"
+end
+
+ip = "27.10.228.9"
+answer = s.memorySearch ip
+puts "#{ip} , answer = #{answer}"