k-space/nyancat-server
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Document, document, document.

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This commit is contained in:
Kevin Lange 2011-12-04 04:03:30 -06:00
parent 24575e61ec
commit 0efd68d3f0
1 changed files with 88 additions and 25 deletions
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99
src/nyancat.c
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@ -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
@ -102,14 +126,21 @@ 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) {
/* 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(&current);
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;