+/*
+ * © 2018 Aaron Taylor <ataylor at subgeniuskitty dot com>
+ * See LICENSE.txt file for copyright and license details.
+ */
+
+#include <stdio.h>
+#include <stdlib.h>
+#include <stdbool.h>
+#include <unistd.h>
+#include <errno.h>
+#include <signal.h>
+#include <string.h>
+#include <sys/types.h>
+#include <sys/socket.h>
+#include <netinet/in.h>
+#include <arpa/inet.h>
+#include <netdb.h>
+#include <SDL2/SDL.h>
+#include <SDL2/SDL_ttf.h>
+
+#define VERSION 1
+
+#define DEFAULT_PORT "4999"
+#define MAX_STRING 255
+#define BITSPERWORD 32
+
+#define WINDOW_HEIGHT 1000
+#define WINDOW_WIDTH 1000
+#define DOT_HEIGHT (WINDOW_HEIGHT / 140)
+#define DOT_WIDTH (WINDOW_WIDTH / 140)
+#define CHUNK_HEIGHT (DOT_HEIGHT * 4)
+#define CHUNK_WIDTH (DOT_WIDTH * 8)
+#define FONT_WIDTH (DOT_WIDTH * 4)
+#define BORDER (DOT_WIDTH * 3)
+
+void
+print_usage(char ** argv)
+{
+ printf( "NED Front Panel v%d (www.subgeniuskitty.com)\n"
+ "Usage: %s\n"
+ " -h Help (prints this message)\n"
+ " -f <path, optional> Path to a TTF file.\n"
+ " Default is './liberation_mono.tff'.\n"
+ " -p <port, optional> Port to listen on for NED snapshots.\n"
+ " Default is 4999.\n"
+ , VERSION, argv[0]
+ );
+}
+
+void
+word_to_leds(uint32_t voffset, uint32_t hoffset, uint32_t word, SDL_Renderer * renderer)
+{
+ SDL_Rect r;
+
+ for (int i=0; i<8; i++) {
+ if (i%2) {
+ SDL_SetRenderDrawColor(renderer, 100, 150, 100, SDL_ALPHA_OPAQUE);
+ } else {
+ SDL_SetRenderDrawColor(renderer, 100, 100, 150, SDL_ALPHA_OPAQUE);
+ }
+ r.x = ((CHUNK_WIDTH * i) + hoffset);
+ r.y = voffset;
+ r.h = CHUNK_HEIGHT;
+ r.w = CHUNK_WIDTH;
+ SDL_RenderFillRect(renderer, &r);
+ }
+
+ for (int i=0; i<BITSPERWORD; i++) {
+ r.x = ((((2 * (BITSPERWORD - i)) * DOT_WIDTH) - (1.5 * DOT_WIDTH)) + hoffset);
+ r.y = (voffset + (2 * DOT_HEIGHT));
+ r.w = DOT_WIDTH;
+ r.h = DOT_HEIGHT;
+ if (((word >> i)) & 1) {
+ SDL_SetRenderDrawColor(renderer, 255, 255, 255, SDL_ALPHA_OPAQUE);
+ } else {
+ SDL_SetRenderDrawColor(renderer, 0, 0, 0, SDL_ALPHA_OPAQUE);
+ }
+ SDL_RenderFillRect(renderer, &r);
+ }
+}
+
+void
+print_text(uint32_t voffset, uint32_t hoffset, char * str, TTF_Font * font, SDL_Renderer * renderer)
+{
+ SDL_Rect r;
+
+ r.x = hoffset;
+ r.y = voffset;
+ r.h = CHUNK_HEIGHT;
+ r.w = (FONT_WIDTH * strnlen(str, MAX_STRING));
+
+ SDL_Color white = {255,255,255};
+
+ SDL_Surface * surface = TTF_RenderText_Solid(font, str, white);
+ SDL_Texture * texture = SDL_CreateTextureFromSurface(renderer, surface);
+ SDL_RenderCopy(renderer, texture, NULL, &r);
+
+ SDL_DestroyTexture(texture);
+ SDL_FreeSurface(surface);
+}
+
+void
+sdl_init(SDL_Window ** window, SDL_Renderer ** renderer, TTF_Font ** font, char * font_path)
+{
+ /* Initialize SDL subsystems. */
+ /* We require the VIDEO subsystem for display. */
+ /* The EVENTS and FILE I/O subsystems are initialized by default. */
+ SDL_Init(SDL_INIT_VIDEO);
+ if(TTF_Init() == -1) printf("TTF_Init: %s\n", TTF_GetError());
+
+ /* Create an SDL window and renderer, and populate the pointers. */
+ SDL_CreateWindowAndRenderer(WINDOW_WIDTH, WINDOW_HEIGHT, SDL_WINDOW_RESIZABLE, window, renderer);
+
+ /* Clear window so it appears normal to user. */
+ SDL_SetRenderDrawColor(*renderer, 128, 128, 128, SDL_ALPHA_OPAQUE);
+ SDL_RenderClear(*renderer);
+ SDL_RenderPresent(*renderer);
+
+ *font = TTF_OpenFont(font_path, 24);
+ if (font == NULL) printf("TTF_OpenFont: %s\n", TTF_GetError());
+}
+
+void
+sigint_handler(int sig)
+{
+ exit(EXIT_SUCCESS);
+}
+
+bool
+valid_sequence_number(uint32_t new_sn)
+{
+ static uint32_t old_sn;
+
+ /* Comparison is "new_sn > old_sn" per RFC1982: Serial Number Arithmetic. */
+ if (
+ ((new_sn < old_sn) && ((old_sn - new_sn) > (0x80000000)))
+ ||
+ ((new_sn > old_sn) && ((new_sn - old_sn) < (0x80000000)))
+ ) {
+ old_sn = new_sn;
+ return true;
+ } else {
+ return false;
+ }
+}
+
+int
+main(int argc, char ** argv)
+{
+ /*
+ * Process command line arguments
+ */
+ int c;
+ char * font_path = NULL;
+ char * fp_port = NULL;
+ while ((c = getopt(argc,argv,"hp:f:")) != -1) {
+ switch (c) {
+ case 'f':
+ // TODO: What do I want to consider valid input?
+ font_path = optarg;
+ break;
+ case 'p':
+ // TODO: What do I want to consider valid input?
+ fp_port = optarg;
+ break;
+ case 'h':
+ print_usage(argv);
+ exit(EXIT_SUCCESS);
+ break;
+ default:
+ break;
+ }
+ }
+
+ /*
+ * Initialization
+ */
+ if (font_path == NULL) asprintf(&font_path, "./liberation_mono.ttf");
+ if (fp_port == NULL) asprintf(&fp_port, "4999");
+
+ signal(SIGINT, sigint_handler);
+
+ SDL_Window * window;
+ SDL_Renderer * renderer;
+ TTF_Font * font;
+
+ sdl_init(&window, &renderer, &font, font_path);
+
+ int sockfd;
+ struct addrinfo hints;
+ struct addrinfo * servinfo;
+ struct addrinfo * p;
+ int rv;
+
+ memset(&hints, 0, sizeof(hints));
+ hints.ai_family = AF_INET;
+ hints.ai_socktype = SOCK_DGRAM;
+ hints.ai_flags = AI_PASSIVE;
+ if ((rv = getaddrinfo(NULL, fp_port, &hints, &servinfo)) != 0) {
+ fprintf(stderr, "ERROR: getaddrinfo: %s\n", gai_strerror(rv));
+ exit(EXIT_FAILURE);
+ }
+ for (p = servinfo; p != NULL; p = p->ai_next) {
+ if ((sockfd = socket(p->ai_family, p->ai_socktype, p->ai_protocol)) == -1) {
+ continue;
+ }
+ if (bind(sockfd, p->ai_addr, p->ai_addrlen) == -1) {
+ close(sockfd);
+ continue;
+ }
+ break;
+ }
+ if (p == NULL) {
+ fprintf(stderr, "ERROR: Failed to bind to socket.\n");
+ exit(EXIT_FAILURE);
+ }
+ freeaddrinfo(servinfo);
+
+ while(1) {
+ /*
+ * Datagram format (all entries are 4 bytes):
+ * Sequence number (See RFC1982)
+ * Currently executing word
+ * PC
+ * SC
+ * PSW
+ * SP
+ * Top 16 stack entries
+ * RAM start address
+ * Top 16 RAM words from start address
+ */
+
+ uint32_t word[39];
+ socklen_t addr_len;
+ int numbytes;
+ struct sockaddr_storage their_addr;
+ char * msg;
+
+ addr_len = sizeof their_addr;
+ if ((numbytes = recvfrom(sockfd, word, 156, 0,
+ (struct sockaddr *) &their_addr, &addr_len)) == -1
+ ) {
+ fprintf(stderr, "WARNING: Unable to receive matching snapshot packet.\n");
+ }
+
+ if ((numbytes == 156) && valid_sequence_number(word[0])) {
+ /* Clear the screen */
+ SDL_SetRenderDrawColor(renderer, 128, 128, 128, SDL_ALPHA_OPAQUE);
+ SDL_RenderClear(renderer);
+
+ /* Write the PC */
+ asprintf(&msg, "PC: 0x%08x", word[2]);
+ print_text((1 * CHUNK_HEIGHT), BORDER, msg, font, renderer);
+ free(msg);
+ word_to_leds((2 * CHUNK_HEIGHT), BORDER, word[2], renderer);
+
+ /* Write the SC */
+ asprintf(&msg, "SC: 0x%08x", word[3]);
+ print_text((4 * CHUNK_HEIGHT), BORDER, msg, font, renderer);
+ free(msg);
+ word_to_leds((5 * CHUNK_HEIGHT), BORDER, word[3], renderer);
+
+ /* Write the stack */
+ asprintf(&msg, "TOS@%u", word[5]);
+ print_text((7 * CHUNK_HEIGHT), BORDER, msg, font, renderer);
+ free(msg);
+ for (int i=0; i<16; i++) {
+ word_to_leds(((i+8) * CHUNK_HEIGHT), BORDER, word[(i+6)], renderer);
+ }
+
+ /* Write the CW */
+ asprintf(&msg, "CW: 0x%08x", word[1]);
+ print_text((1 * CHUNK_HEIGHT), ((WINDOW_WIDTH / 2) + BORDER), msg, font, renderer);
+ free(msg);
+ word_to_leds((2 * CHUNK_HEIGHT), ((WINDOW_WIDTH / 2) + BORDER), word[1], renderer);
+
+ /* Write the PSW */
+ asprintf(&msg, "PSW: 0x%08x", word[4]);
+ print_text((4 * CHUNK_HEIGHT), ((WINDOW_WIDTH / 2) + BORDER), msg, font, renderer);
+ free(msg);
+ word_to_leds((5 * CHUNK_HEIGHT), ((WINDOW_WIDTH / 2) + BORDER), word[4], renderer);
+
+ /* Write the RAM dump */
+ asprintf(&msg, "RAM: 0x%08x", word[22]);
+ print_text((7 * CHUNK_HEIGHT), ((WINDOW_WIDTH / 2) + BORDER), msg, font, renderer);
+ free(msg);
+ for (int i=0; i<16; i++) {
+ word_to_leds(((i+8) * CHUNK_HEIGHT), ((WINDOW_WIDTH / 2) + BORDER), word[(i+23)], renderer);
+ }
+
+ /* Render */
+ SDL_RenderPresent(renderer);
+ }
+ }
+
+ close(sockfd);
+ exit(EXIT_SUCCESS);
+}