add a UDPSocket class to abstract communication to agents

Source/UDPSocket.cpp

@@ -0,0 +1,70 @@
+//
+//  UDPSocket.cpp
+//  interface
+//
+//  Created by Stephen Birarda on 1/28/13.
+//  Copyright (c) 2013 Rosedale Lab. All rights reserved.
+//
+
+#include "UDPSocket.h"
+#include <sys/socket.h>
+#include <arpa/inet.h>
+#include <fcntl.h>
+
+struct sockaddr_in UDPSocket::sockaddr_util(char* hostname, int port) {
+    sockaddr_in dest_address;
+    
+    dest_address.sin_family = AF_INET;
+    dest_address.sin_addr.s_addr = inet_addr(hostname);
+    dest_address.sin_port = htons((uint16_t)port);
+    
+    return dest_address;
+}
+
+struct sockaddr_in dest_sockaddr;
+
+UDPSocket::UDPSocket(int listeningPort) {
+    // create the socket
+    handle = socket(AF_INET, SOCK_DGRAM, IPPROTO_UDP);
+    
+    if (handle <= 0) {
+        printf("Failed to create socket.\n");
+        return;
+    }
+    
+    // instantiate the re-usable dest_sockaddr with a dummy IP and port
+    dest_sockaddr = UDPSocket::sockaddr_util((char *) "1.0.0.0", 1);
+    
+    // bind the socket to the passed listeningPort
+    sockaddr_in bind_address = UDPSocket::sockaddr_util(INADDR_ANY, listeningPort);
+    
+    if (bind(handle, (const sockaddr*) &bind_address, sizeof(sockaddr_in)) < 0) {
+        printf("Failed to bind socket to port %d.\n", listeningPort);
+        return;
+    }
+    
+    //  set socket as non-blocking
+    int nonBlocking = 1;
+    if (fcntl(handle, F_SETFL, O_NONBLOCK, nonBlocking) == -1) {
+        printf("Failed to set non-blocking socket\n");
+        return;
+    }
+}
+
+int UDPSocket::send(char * dest_address, int dest_port, const void *data, int length_in_bytes) {
+    
+    // change address and port on reusable global to passed variables
+    dest_sockaddr.sin_addr.s_addr = inet_addr(dest_address);
+    dest_sockaddr.sin_port = htons((uint16_t)dest_port);
+    
+    // send data via UDP
+    int sent_bytes = sendto(handle, (const char*)data, length_in_bytes,
+                        0, (sockaddr*)&dest_address, sizeof(sockaddr_in));
+    
+    if (sent_bytes != length_in_bytes) {
+        printf("Failed to send packet: return value = %d\n", sent_bytes);
+        return false;
+    }
+    
+    return sent_bytes;
+}

Source/UDPSocket.h

@@ -0,0 +1,33 @@
+//
+//  UDPSocket.h
+//  interface
+//
+//  Created by Stephen Birarda on 1/28/13.
+//  Copyright (c) 2013 Rosedale Lab. All rights reserved.
+//
+
+#ifndef __interface__UDPSocket__
+#define __interface__UDPSocket__
+
+#include <iostream>
+#include <netinet/in.h>
+
+class UDPSocket {    
+    public:
+        static struct sockaddr_in sockaddr_util(char *address, int port);
+    
+    UDPSocket(int listening_port);
+        int send(char * dest_address, int dest_port, const void *data, int length_in_bytes);
+    private:
+        UDPSocket(); // private default constructor
+        int handle;
+    
+        struct AgentData {
+            char * address;
+            int listening_port;
+        };
+
+        AgentData *known_agents;
+};
+
+#endif /* defined(__interface__UDPSocket__) */

interface.xcodeproj/project.pbxproj

@@ -54,6 +54,7 @@
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 		533BF9D516B31A4700AC31BB /* jeska.raw in CopyFiles */ = {isa = PBXBuildFile; fileRef = 533BF9D316B31A3B00AC31BB /* jeska.raw */; };
 		538BA8A316B1B71E000BF99C /* love.raw in CopyFiles */ = {isa = PBXBuildFile; fileRef = 538BA8A216B1B719000BF99C /* love.raw */; };
+		539853CE16B765EE00B2D585 /* UDPSocket.cpp in Sources */ = {isa = PBXBuildFile; fileRef = 539853CC16B765EE00B2D585 /* UDPSocket.cpp */; };
 		B6BDADE115F44A9D002A07DF /* CoreServices.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = B6BDADDE15F444DB002A07DF /* CoreServices.framework */; };
 		B6BDADE215F44AA5002A07DF /* CoreAudio.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = B6BDADD815F444C1002A07DF /* CoreAudio.framework */; };
 		B6BDADE315F44AB0002A07DF /* AudioToolbox.framework in Frameworks */ = {isa = PBXBuildFile; fileRef = B6BDADDA15F444C9002A07DF /* AudioToolbox.framework */; };
@@ -509,6 +510,8 @@
 		533B578516B2160600FCABF1 /* grayson.raw */ = {isa = PBXFileReference; lastKnownFileType = file; path = grayson.raw; sourceTree = "<group>"; };
 		533BF9D316B31A3B00AC31BB /* jeska.raw */ = {isa = PBXFileReference; lastKnownFileType = file; path = jeska.raw; sourceTree = "<group>"; };
 		538BA8A216B1B719000BF99C /* love.raw */ = {isa = PBXFileReference; lastKnownFileType = file; path = love.raw; sourceTree = "<group>"; };
+		539853CC16B765EE00B2D585 /* UDPSocket.cpp */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.cpp.cpp; path = UDPSocket.cpp; sourceTree = "<group>"; };
+		539853CD16B765EE00B2D585 /* UDPSocket.h */ = {isa = PBXFileReference; fileEncoding = 4; lastKnownFileType = sourcecode.c.h; path = UDPSocket.h; sourceTree = "<group>"; };
 		8DD76F6C0486A84900D96B5E /* interface */ = {isa = PBXFileReference; explicitFileType = "compiled.mach-o.executable"; includeInIndex = 0; path = interface; sourceTree = BUILT_PRODUCTS_DIR; };
 		B6BDADD815F444C1002A07DF /* CoreAudio.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = CoreAudio.framework; path = System/Library/Frameworks/CoreAudio.framework; sourceTree = SDKROOT; };
 		B6BDADDA15F444C9002A07DF /* AudioToolbox.framework */ = {isa = PBXFileReference; lastKnownFileType = wrapper.framework; name = AudioToolbox.framework; path = System/Library/Frameworks/AudioToolbox.framework; sourceTree = SDKROOT; };
@@ -628,6 +631,8 @@
 				5325C24D16AF4DBE0051A40B /* util.cpp */,
 				5325C24E16AF4DBE0051A40B /* util.h */,
 				5325C24F16AF4DBE0051A40B /* world.h */,
+				539853CC16B765EE00B2D585 /* UDPSocket.cpp */,
+				539853CD16B765EE00B2D585 /* UDPSocket.h */,
 			);
 			path = Source;
 			sourceTree = "<group>";
@@ -1368,6 +1373,7 @@
 				5325C26016AF4DBE0051A40B /* texture.cpp in Sources */,
 				5325C26116AF4DBE0051A40B /* util.cpp in Sources */,
 				5325C26416AF4E2C0051A40B /* audio.cpp in Sources */,
+				539853CE16B765EE00B2D585 /* UDPSocket.cpp in Sources */,
 			);
 			runOnlyForDeploymentPostprocessing = 0;
 		};