nodejs client finish binary search

binding/nodejs/ip2region.js

@@ -1,55 +1,87 @@
 /**
  * ip2region client for nodejs
  *
- * project: https://github.com/lionsoul2016/ip2region
+ * project: https://github.com/lionsoul2014/ip2region
  *
  * @author dongyado<dongyado@gmail.com>
  * */
-
-
-function Ip2region(db_path)
-{
 var fs   = require('fs');
+
 var ipbase = [16777216, 65536, 256, 1]; // for ip2long
-    var db_file_path   = null;
+var ip2region = {};
-    var db_fd          = null;
+ip2region.db_file_path   = null;
-
+ip2region.db_fd          = null;
-    // db file check
-    if (typeof(db_path) == "undefined" || fs.exists(db_path) ) {
-        throw("[ip2region] db file not exists : " + db_path);
-    }
-    
-    db_file_path = db_path; 
-
-    try {
-        db_fd = fs.openSync(db_file_path, 'r');
-    } catch(e) {
-        throw("[ip2region] Can not open ip2region.db file , path : " + db_file_path);
-    }
 
 var totalBlocks         = 0;
 var firstIndexPtr       = 0;
 var lastIndexPtr        = 0;
 var superBlock          = new Buffer(8);
 
-    this.binarySearch = function(ip)
+var indexBlockLength    = 12;
-    {
+var totalHeaderLength   = 4096;
-        if (typeof(ip) == 'string') ip = ip2long(ip);
 
-        // init basic search environment
+
-        if (totalBlocks == 0) {
+/**
-            fs.readSync(ip2r.db_fd, superBlock, 0, 8, 0);
+ * binary search
-            firstIndexPtr = getLong(superBlock, 0);
+ * */
-            lastIndexPtr  = getLong(superBlock, 4);
+ip2region.binarySearch = function(ip)
-        }
+{
+    if( typeof(ip) == 'string' ) 
+        ip = ip2long(ip);
 
     // search
+    var low     = 0;
+    var mid     = 0;
+    var high    = totalBlocks;
+    var dataPos = 0;
+    var pos     = 0;
+    var sip     = 0;
+    var eip     = 0;
+    var indexBuffer = new Buffer(12);
 
-        return ip2long(ip);
+    // binary search
+    while( low <= high ) {
+        mid = ((low + high) >> 1);
+        pos = firstIndexPtr + mid * indexBlockLength;
+        fs.readSync(this.db_fd, indexBuffer, 0, indexBlockLength, pos);
+        sip = getLong(indexBuffer, 0);
+
+        //console.log( ' sip : ' + sip + ' eip : ' + eip );
+        if ( ip < sip) {
+            high = mid - 1;
+        } else {
+            eip = getLong(indexBuffer, 4);
+            if ( ip > eip ) {
+                low = mid + 1;
+            } else {
+                dataPos = getLong(indexBuffer, 8);
+                break;
+            }
+        }
+    }
+
+    // read data
+    if (dataPos == 0) return null;
+    var dataLen = ((dataPos >> 24) & 0xFF);
+    var dataPos = (dataPos & 0x00FFFFFF);
+    var dataBuffer = new Buffer(dataLen);
+
+    fs.readSync(this.db_fd, dataBuffer, 0, dataLen, dataPos);
+
+    var city_id = getLong(dataBuffer, 0);
+    var data    = dataBuffer.toString('utf8', 4, dataLen);
+
+    //console.log(city_id);
+    //console.log(data);
+
+    return { city: city_id, region: data };
 }
 
 
-    this.btreeSearch = function(ip) 
+/**
+ * btree search
+ * */
+ip2region.btreeSearch = function(ip) 
 {
     return ip2long(ip);
 }
@@ -74,13 +106,53 @@ function Ip2region(db_path)
  * */
 function getLong(buffer, offset) 
 {
-        return  (   
+    var val =  (   
         (buffer[offset] & 0x000000FF) | 
         ((buffer[offset + 1] <<  8) & 0x0000FF00) | 
         ((buffer[offset + 2] << 16) & 0x00FF0000) |
         ((buffer[offset + 3] << 24) & 0xFF000000)
     );
+
+    // convert to unsigned int
+    if (val < 0) {
+        val = val >>> 0;
     }
+    return val;
 }
 
-module.exports = Ip2region;
+
+// api for create
+exports.create = function(db_path) {
+
+    // db file check
+    if (typeof(db_path) == "undefined" || fs.exists(db_path) ) {
+        throw("[ip2region] db file not exists : " + db_path);
+    }
+    
+    ip2region.db_file_path = db_path; 
+
+    try {
+        ip2region.db_fd = fs.openSync(ip2region.db_file_path, 'r');
+    } catch(e) {
+        throw("[ip2region] Can not open ip2region.db file , path : "
+                + ip2region.db_file_path);
+    }
+
+    // init basic search environment
+    if (totalBlocks == 0) {
+        fs.readSync(ip2region.db_fd, superBlock, 0, 8, 0);
+        firstIndexPtr = getLong(superBlock, 0);
+        lastIndexPtr  = getLong(superBlock, 4);
+        totalBlocks   = (lastIndexPtr - firstIndexPtr) 
+                            / indexBlockLength + 1;
+    }
+
+    return ip2region;
+}
+
+
+// api for destroy
+exports.destroy = function(ip2rObj){
+    ip2rObj.db_file_path = null;
+    fs.closeSync(ip2rObj.db_fd);
+}

binding/nodejs/test.js

@@ -3,6 +3,13 @@
  * */
 
 var Ip2region = require('./ip2region');
-var ip2region = new Ip2region('../../data/ip2region.db'); 
+//var ip2region = new Ip2region(); 
 
-console.log(ip2region.binarySearch("255.255.255.255"));
+// 1. create a ip2region object
+var ipObj = Ip2region.create('../../data/ip2region.db');
+
+// 2. use
+console.log(ipObj.binarySearch("120.24.78.68"));
+
+// 3. destroy
+Ip2region.destroy(ipObj);