diff options
| -rw-r--r-- | src/nyancat.c | 113 |
1 files changed, 88 insertions, 25 deletions
diff --git a/src/nyancat.c b/src/nyancat.c index 46cd6c1..5f4c702 100644 --- a/src/nyancat.c +++ b/src/nyancat.c @@ -47,29 +47,55 @@ #include <signal.h> #include <time.h> #include <setjmp.h> + +/* + * telnet.h contains some #defines for the various + * commands, escape characters, and modes for telnet. + * (it surprises some people that telnet is, really, + * a protocol, and not just raw text transmission) + */ #include "telnet.h" -/* The animation frames are stored separately. */ +/* + * The animation frames are stored separately in + * this header so they don't clutter the core source + */ #include "animation.h" -/* The color palette is not yet set */ +/* + * Color palette to use for final output + * Specifically, this should be either control sequences + * or raw characters (ie, for vt220 mode) + */ char * colors[256] = {NULL}; + /* * For most modes, we ouput spaces, but for some - * we will use block characters. + * we will use block characters (or even nothing) */ char * output = " "; -/* Telnet mode? */ +/* + * Are we currently in telnet mode? + */ int telnet = 0; -/* I refuse to include libm */ -double log10(double x) { - int val = (int)x; +/* + * Environment to use for setjmp/longjmp + * when breaking out of options handler + */ +jmp_buf environment; + + +/* + * I refuse to include libm to keep this low + * on external dependencies. + * */ +int digits(int val) { int d = 1, c; if (val >= 0) for (c = 10; c <= val; c *= 10) d++; else for (c = -10 ; c >= val; c *= 10) d++; - return (c < 0) ? (double)++d : (double)d; + return (c < 0) ? ++d : d; } /* @@ -90,8 +116,6 @@ void SIGINT_handler(int sig){ exit(0); } -jmp_buf environment; - /* * Handle the alarm which breaks us off of options * handling if we didn't receive a terminal @@ -102,16 +126,23 @@ void SIGALRM_handler(int sig) { /* Unreachable */ } +/* + * Telnet requires us to send a specific sequence + * for a line break (\r\000\n), so let's make it happy. + */ void newline(int n) { int i = 0; for (i = 0; i < n; ++i) { - if (telnet) { - putc('\r', stdout); - putc(0, stdout); - putc('\n', stdout); - } else { - putc('\n', stdout); - } + /* We will send `n` linefeeds to the client */ + if (telnet) { + /* Send the telnet newline sequence */ + putc('\r', stdout); + putc(0, stdout); + putc('\n', stdout); + } else { + /* Send a regular line feed */ + putc('\n', stdout); + } } } @@ -155,6 +186,10 @@ void set_options() { telnet_willack[NEW_ENVIRON] = DO; } +/* + * Send a command (cmd) to the telnet client + * Also does special handling for DO/DONT/WILL/WONT + */ void send_command(int cmd, int opt) { /* Send a command to the telnet client */ if (cmd == DO || cmd == DONT) { @@ -234,6 +269,8 @@ int main(int argc, char ** argv) { /* End of extended option mode */ sb_mode = 0; if (sb[0] == TTYPE) { + /* This was a response to the TTYPE command, meaning + * that this should be a terminal type */ alarm(0); strcpy(term, &sb[2]); goto ready; @@ -249,6 +286,7 @@ int main(int argc, char ** argv) { /* Will / Won't Negotiation */ opt = getchar(); if (!telnet_willack[opt]) { + /* We default to WONT */ telnet_willack[opt] = WONT; } send_command(telnet_willack[opt], opt); @@ -264,6 +302,7 @@ int main(int argc, char ** argv) { /* Do / Don't Negotation */ opt = getchar(); if (!telnet_options[opt]) { + /* We default to DONT */ telnet_options[opt] = DONT; } send_command(telnet_options[opt], opt); @@ -281,7 +320,7 @@ int main(int argc, char ** argv) { memset(sb, 0, 1024); break; case IAC: - /* Connection Closed During Negotiation */ + /* IAC IAC? That's probably not right. */ done = 1; break; default: @@ -290,6 +329,13 @@ int main(int argc, char ** argv) { } else if (sb_mode) { /* Extended Option Mode -> Accept character */ if (sb_len < 1023) { + /* Append this character to the SB string, + * but only if it doesn't put us over + * our limit; honestly, we shouldn't hit + * the limit, as we're only collecting characters + * for a terminal type, but better safe than + * sorry (and vulernable). + */ sb[sb_len] = i; sb_len++; } @@ -298,11 +344,20 @@ int main(int argc, char ** argv) { } } } else { - /* Otherwise, we were run standalone, find the terminal type from the environement */ + /* We are running standalone, retrieve the + * terminal type from the environment. */ char * nterm = getenv("TERM"); strcpy(term, nterm); } + /* + * Labels. Yes, and I used a goto. + * If you're going to complain about this, you + * really need to reevaluate your approach to getting + * things done. This works, it works well, and there + * is absolutely, positively nothing wrong with using + * goto in C, so I'm going to do it. + */ ready: /* Convert the entire terminal string to lower case */ @@ -478,10 +533,10 @@ ready: time_t start, current; time(&start); - int playing = 1; - size_t i = 0; - char last = 0; - size_t y, x; + int playing = 1; /* Animation should continue [left here for modifications] */ + size_t i = 0; /* Current frame # */ + char last = 0; /* Last color index rendered */ + size_t y, x; /* x/y coordinates of what we're drawing */ while (playing) { /* Render the frame */ for (y = MIN_ROW; y < MAX_ROW; ++y) { @@ -503,15 +558,23 @@ ready: /* End of row, send newline */ newline(1); } + /* Get the current time for the "You have nyaned..." string */ time(¤t); double diff = difftime(current, start); - double nLen = log10(diff); - int width = (80 - 29 - (int)nLen) / 2; + /* Now count the length of the time difference so we can center */ + int nLen = int(diff); + int width = (80 - 29 - nLen) / 2; + /* Spit out some spaces so that we're actually centered */ while (width) { printf(" "); width--; } + /* You have nyaned for [n] seconds! + * The \033[J ensures that the rest of the line has the dark blue + * background, and the \033[1;37m ensures that our text is bright white + */ printf("\033[1;37mYou have nyaned for %0.0f seconds!\033[J", diff); + /* Reset the last color so that the escape sequences rewrite */ last = 0; /* Update frame crount */ ++i; |