refine core, move specified functions to kernel utility.

trunk/src/kernel/srs_kernel_utility.cpp

@@ -23,8 +23,13 @@ CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 
 #include <srs_kernel_utility.hpp>
 
-#include <sys/time.h>
 #include <unistd.h>
+#include <string.h>
+#include <netdb.h>
+#include <arpa/inet.h>
+#include <sys/time.h>
+
+using namespace std;
 
 #include <srs_kernel_log.hpp>
 
@@ -58,3 +63,122 @@ void srs_update_system_time_ms()
     
     _srs_system_time_us_cache = now_us;
 }
+
+string srs_dns_resolve(string host)
+{
+    if (inet_addr(host.c_str()) != INADDR_NONE) {
+        return host;
+    }
+    
+    hostent* answer = gethostbyname(host.c_str());
+    if (answer == NULL) {
+        return "";
+    }
+    
+    char ipv4[16];
+    memset(ipv4, 0, sizeof(ipv4));
+    for (int i = 0; i < answer->h_length; i++) {
+        inet_ntop(AF_INET, answer->h_addr_list[i], ipv4, sizeof(ipv4));
+        break;
+    }
+    
+    return ipv4;
+}
+
+bool srs_is_little_endian()
+{
+    // convert to network(big-endian) order, if not equals, 
+    // the system is little-endian, so need to convert the int64
+    static int little_endian_check = -1;
+    
+    if(little_endian_check == -1) {
+        union {
+            int32_t i;
+            int8_t c;
+        } little_check_union;
+        
+        little_check_union.i = 0x01;
+        little_endian_check = little_check_union.c;
+    }
+    
+    return (little_endian_check == 1);
+}
+
+string srs_string_replace(string str, string old_str, string new_str)
+{
+    std::string ret = str;
+    
+    if (old_str == new_str) {
+        return ret;
+    }
+    
+    size_t pos = 0;
+    while ((pos = ret.find(old_str, pos)) != std::string::npos) {
+        ret = ret.replace(pos, old_str.length(), new_str);
+    }
+    
+    return ret;
+}
+
+string srs_string_trim_end(string str, string trim_chars)
+{
+    std::string ret = str;
+    
+    for (int i = 0; i < (int)trim_chars.length(); i++) {
+        char ch = trim_chars.at(i);
+        
+        while (!ret.empty() && ret.at(ret.length() - 1) == ch) {
+            ret.erase(ret.end() - 1);
+            
+            // ok, matched, should reset the search
+            i = 0;
+        }
+    }
+    
+    return ret;
+}
+
+string srs_string_trim_start(string str, string trim_chars)
+{
+    std::string ret = str;
+    
+    for (int i = 0; i < (int)trim_chars.length(); i++) {
+        char ch = trim_chars.at(i);
+        
+        while (!ret.empty() && ret.at(0) == ch) {
+            ret.erase(ret.begin());
+            
+            // ok, matched, should reset the search
+            i = 0;
+        }
+    }
+    
+    return ret;
+}
+
+string srs_string_remove(string str, string remove_chars)
+{
+    std::string ret = str;
+    
+    for (int i = 0; i < (int)remove_chars.length(); i++) {
+        char ch = remove_chars.at(i);
+        
+        for (std::string::iterator it = ret.begin(); it != ret.end();) {
+            if (ch == *it) {
+                it = ret.erase(it);
+                
+                // ok, matched, should reset the search
+                i = 0;
+            } else {
+                ++it;
+            }
+        }
+    }
+    
+    return ret;
+}
+
+bool srs_string_ends_with(string str, string flag)
+{
+    return str.rfind(flag) == str.length() - flag.length();
+}