ZRJ · September 2, 2019 04:26 · Dec 29, 2014 · Dec 29, 2014
diff --git a/IP17MON.cpp b/IP17MON.cpp
@@ -18,7 +18,7 @@ class IP17MON {
             printf("%m\n");
             return false;
         }
-        // reverse
+        // std vector reserve
         vecDataFile.assign(std::istreambuf_iterator<char>(ifDataFile), std::istreambuf_iterator<char>());
         printf("Load %lu bytes success\n", vecDataFile.size());
 

diff --git a/IP17MON.cpp b/IP17MON.cpp
@@ -0,0 +1,80 @@
+#include <stdio.h>
+#include <stdlib.h>
+#include <string.h>
+#include <string>
+#include <vector>
+#include <fstream>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <assert.h>
+
+class IP17MON {
+public:
+    bool init(const std::string strPathToDataFile = "./17monipdb.dat") {
+        printf("Opening %s\n", strPathToDataFile.c_str());
+        std::ifstream ifDataFile(strPathToDataFile.c_str(), std::ios::binary);
+        if (ifDataFile.is_open() == false) {
+            printf("%m\n");
+            return false;
+        }
+        // reverse
+        vecDataFile.assign(std::istreambuf_iterator<char>(ifDataFile), std::istreambuf_iterator<char>());
+        printf("Load %lu bytes success\n", vecDataFile.size());
+
+        unsigned int uiIndexLen = 0;
+        memcpy(&uiIndexLen, &vecDataFile[0], 4);
+        uiIndexLen = ntohl(uiIndexLen);
+        pIPIndex = &vecDataFile[4];
+        pIPData = &vecDataFile[uiIndexLen];
+
+        return true;
+    }
+    std::string find(const std::string strIP) {        
+        struct sockaddr_in stSockAddrInet = {0};
+        if(inet_aton(strIP.c_str(), &stSockAddrInet.sin_addr) == 0) {
+            //printf("convert error\n");
+            return "";
+        }
+        unsigned int uiIP = ntohl(stSockAddrInet.sin_addr.s_addr);
+
+        // atoi The string can contain additional characters after those 
+        // that form the integral number, which are ignored and have no 
+        // effect on the behavior of this function.
+        int iFirst = atoi(strIP.c_str());
+        int iStart = 0;
+        memcpy(&iStart, pIPIndex+(iFirst*4), 4);
+        int iMaxComLen = pIPData - pIPIndex - 1024 - 4;
+
+        int iIndexOffset = -1;
+        unsigned char ucIndexLength = 0;
+        for (iStart = iStart * 8 + 1024; iStart < iMaxComLen; iStart += 8) {
+            unsigned int uiCurrIP = 0;
+            memcpy(&uiCurrIP, pIPIndex+iStart, 4);
+            uiCurrIP = ntohl(uiCurrIP);
+            if (uiCurrIP >= uiIP) {
+                iIndexOffset = 0;
+                memcpy(&iIndexOffset, pIPIndex+iStart+4, 3);   
+                memcpy(&ucIndexLength, pIPIndex+iStart+7, 1);  
+                break;
+            }
+        }
+
+        if (iIndexOffset == -1) {
+            return "";
+        }
+
+        std::string strRegion(pIPData + iIndexOffset - 1024, ucIndexLength);
+        return strRegion;
+    }
+private:
+    std::vector<char> vecDataFile;
+    char *pIPIndex, *pIPData;
+};
+
+int main() {
+    IP17MON oIP17MON;
+    assert(oIP17MON.init());
+    printf("%s -> %s\n", "14.17.22.40", oIP17MON.find("14.17.22.40").c_str());    
+    return 0;
+}