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-rw-r--r--src/nyancat.c201
1 files changed, 143 insertions, 58 deletions
diff --git a/src/nyancat.c b/src/nyancat.c
index 7554630..5fa8825 100644
--- a/src/nyancat.c
+++ b/src/nyancat.c
@@ -4,6 +4,16 @@
* Developed by: Kevin Lange
* http://github.com/klange/nyancat
*
+ * This is a simple telnet server / standalone application which renders the
+ * classic Nyan Cat (or "poptart cat") to your terminal.
+ *
+ * It makes use of various ANSI escape sequences to render color, or in the case
+ * of a VT220, simply dumps text to the screen.
+ *
+ * For more information, please see:
+ *
+ * http://miku.acm.uiuc.edu
+ *
* Permission is hereby granted, free of charge, to any person obtaining a copy
* of this software and associated documentation files (the "Software"), to
* deal with the Software without restriction, including without limitation the
@@ -37,54 +47,95 @@
#include <signal.h>
#include "telnet.h"
+/* The animation frames are stored separately. */
#include "animation.h"
+
+/* The color palette is not yet set */
char * colors[256] = {NULL};
+/*
+ * For most modes, we ouput spaces, but for some
+ * we will use block characters.
+ */
char * output = " ";
+/*
+ * These values crop the animation, as we have a full 64x64 stored,
+ * but we only want to display 80x24.
+ */
#define MIN_ROW 20
#define MAX_ROW 44
-
#define MIN_COL 10
#define MAX_COL 50
+/*
+ * In the standalone mode, we want to handle an interrupt signal
+ * (^C) so that we can restore the cursor.
+ */
void SIGINT_handler(int sig){
printf("\033[?25h");
exit(0);
}
+/*
+ * These are the options we want to use as
+ * a telnet server. These are set in set_options()
+ */
unsigned char telnet_options[256] = { 0 };
unsigned char telnet_willack[256] = { 0 };
+/*
+ * These are the values we have set or
+ * agreed to during our handshake.
+ * These are set in send_command(...)
+ */
unsigned char telnet_do_set[256] = { 0 };
unsigned char telnet_will_set[256]= { 0 };
+/*
+ * Set the default options for the telnet server.
+ */
void set_options() {
+ /* We will not echo input */
telnet_options[ECHO] = WONT;
+ /* We will set graphics modes */
telnet_options[SGA] = WILL;
+ /* We will not set new environments */
telnet_options[NEW_ENVIRON] = WONT;
+ /* The client should echo its own input */
telnet_willack[ECHO] = DO;
+ /* The client can set a graphics mode */
telnet_willack[SGA] = DO;
+ /* The client should not change the window size */
telnet_willack[NAWS] = DONT;
+ /* The client should tell us its terminal type (very important) */
telnet_willack[TTYPE] = DO;
+ /* No linemode */
telnet_willack[LINEMODE] = DONT;
+ /* And the client can set a new environment */
telnet_willack[NEW_ENVIRON] = DO;
}
void send_command(int cmd, int opt) {
+ /* Send a command to the telnet client */
if (cmd == DO || cmd == DONT) {
+ /* DO commands say what the client should do. */
if (((cmd == DO) && (telnet_do_set[opt] != DO)) ||
((cmd == DONT) && (telnet_do_set[opt] != DONT))) {
+ /* And we only send them if there is a disagreement */
telnet_do_set[opt] = cmd;
printf("%c%c%c", IAC, cmd, opt);
}
} else if (cmd == WILL || cmd == WONT) {
+ /* Similarly, WILL commands say what the server will do. */
if (((cmd == WILL) && (telnet_will_set[opt] != WILL)) ||
((cmd == WONT) && (telnet_will_set[opt] != WONT))) {
+ /* And we only send them during disagreements */
telnet_will_set[opt] = cmd;
printf("%c%c%c", IAC, cmd, opt);
}
} else {
+ /* Other commands are sent raw */
printf("%c%c", IAC, cmd);
}
}
@@ -92,17 +143,23 @@ void send_command(int cmd, int opt) {
int main(int argc, char ** argv) {
+ /* I have a bad habit of being very C99, so this may not be everything */
+ /* The default terminal is ANSI */
+ char term[1024] = {'a','n','s','i'};
int k, ttype;
uint32_t option = 0, done = 0, sb_mode = 0, do_echo = 0;
- char term[1024] = {'a','n','s','i'};
+ /* Various pieces for the telnet communication */
char sb[1024] = {0};
char sb_len = 0;
if (argc > 1) {
if (!strcmp(argv[1], "-t")) {
+ /* Yes, I know, lame way to get arguments, whatever, we only want one of them. */
+ /* Set the default options */
set_options();
+ /* Let the client know what we're using */
for (option = 0; option < 256; option++) {
if (telnet_options[option]) {
send_command(telnet_options[option], option);
@@ -116,13 +173,15 @@ int main(int argc, char ** argv) {
}
}
+ /* Negotiate options */
while (!feof(stdin) && !done) {
unsigned char i = getchar();
unsigned char opt = 0;
- if (i == 255) {
+ if (i == IAC) {
i = getchar();
switch (i) {
case SE:
+ /* End of extended option mode */
sb_mode = 0;
if (sb[0] == TTYPE) {
strcpy(term, &sb[2]);
@@ -130,11 +189,13 @@ int main(int argc, char ** argv) {
}
break;
case NOP:
+ /* No Op */
send_command(NOP, 0);
fflush(stdout);
break;
case WILL:
case WONT:
+ /* Will / Won't Negotiation */
opt = getchar();
if (!telnet_willack[opt]) {
telnet_willack[opt] = WONT;
@@ -142,70 +203,82 @@ int main(int argc, char ** argv) {
send_command(telnet_willack[opt], opt);
fflush(stdout);
if ((i == WILL) && (opt == TTYPE)) {
+ /* WILL TTYPE? Great, let's do that now! */
printf("%c%c%c%c%c%c", IAC, SB, TTYPE, SEND, IAC, SE);
fflush(stdout);
}
break;
case DO:
case DONT:
+ /* Do / Don't Negotation */
opt = getchar();
if (!telnet_options[opt]) {
telnet_options[opt] = DONT;
}
send_command(telnet_options[opt], opt);
if (opt == ECHO) {
+ /* We don't really need this, as we don't accept input, but,
+ * in case we do in the future, set our echo mode */
do_echo = (i == DO);
}
fflush(stdout);
break;
case SB:
+ /* Begin Extended Option Mode */
sb_mode = 1;
sb_len = 0;
memset(sb, 0, 1024);
break;
case IAC:
- /* Connection Closed */
+ /* Connection Closed During Negotiation */
done = 1;
break;
default:
break;
}
} else if (sb_mode) {
- sb[sb_len] = i;
- sb_len++;
+ /* Extended Option Mode -> Accept character */
+ if (sb_len < 1023) {
+ sb[sb_len] = i;
+ sb_len++;
+ }
}
}
}
} else {
+ /* Otherwise, we were run standalone, find the terminal type from the environement */
char * nterm = getenv("TERM");
strcpy(term, nterm);
}
ready:
+ /* Convert the entire terminal string to lower case */
for (k = 0; k < strlen(term); ++k) {
term[k] = tolower(term[k]);
}
+ /* Do our terminal detection */
if (strstr(term, "xterm")) {
- ttype = 1;
+ ttype = 1; /* 256-color, spaces */
} else if (strstr(term, "linux")) {
- ttype = 3;
+ ttype = 3; /* Spaces and blink attribute */
} else if (strstr(term, "vtnt")) {
- ttype = 5;
+ ttype = 5; /* Extended ASCII fallback == Windows */
} else if (strstr(term, "cygwin")) {
- ttype = 5;
+ ttype = 5; /* Extended ASCII fallback == Windows */
} else if (strstr(term, "vt220")) {
- ttype = 6;
+ ttype = 6; /* No color support */
} else if (strstr(term, "fallback")) {
- ttype = 4;
+ ttype = 4; /* Unicode fallback */
} else if (strstr(term, "rxvt")) {
- ttype = 3;
+ ttype = 3; /* Accepts LINUX mode */
} else {
- ttype = 2;
+ ttype = 2; /* Verything else */
}
- int always_escape = 0;
+ int always_escape = 0; /* Used for text mode */
+ /* Accept ^C -> restore cursor */
signal(SIGINT, SIGINT_handler);
switch (ttype) {
case 1:
@@ -257,63 +330,65 @@ ready:
colors['%'] = "\033[5;45m"; /* Pink cheeks */
break;
case 4:
- colors[','] = "\033[0;34;44m"; /* Blue background */
- colors['.'] = "\033[1;37;47m"; /* White stars */
- colors['\''] = "\033[0;30;40m"; /* Black border */
- colors['@'] = "\033[1;37;47m"; /* Tan poptart */
- colors['$'] = "\033[1;35;45m"; /* Pink poptart */
- colors['-'] = "\033[1;31;41m"; /* Red poptart */
- colors['>'] = "\033[1;31;41m"; /* Red rainbow */
- colors['&'] = "\033[0;33;43m"; /* Orange rainbow */
- colors['+'] = "\033[1;33;43m"; /* Yellow Rainbow */
- colors['#'] = "\033[1;32;42m"; /* Green rainbow */
- colors['='] = "\033[1;34;44m"; /* Light blue rainbow */
- colors[';'] = "\033[0;34;44m"; /* Dark blue rainbow */
- colors['*'] = "\033[1;30;40m"; /* Gray cat face */
- colors['%'] = "\033[1;35;45m"; /* Pink cheeks */
+ colors[','] = "\033[0;34;44m"; /* Blue background */
+ colors['.'] = "\033[1;37;47m"; /* White stars */
+ colors['\''] = "\033[0;30;40m"; /* Black border */
+ colors['@'] = "\033[1;37;47m"; /* Tan poptart */
+ colors['$'] = "\033[1;35;45m"; /* Pink poptart */
+ colors['-'] = "\033[1;31;41m"; /* Red poptart */
+ colors['>'] = "\033[1;31;41m"; /* Red rainbow */
+ colors['&'] = "\033[0;33;43m"; /* Orange rainbow */
+ colors['+'] = "\033[1;33;43m"; /* Yellow Rainbow */
+ colors['#'] = "\033[1;32;42m"; /* Green rainbow */
+ colors['='] = "\033[1;34;44m"; /* Light blue rainbow */
+ colors[';'] = "\033[0;34;44m"; /* Dark blue rainbow */
+ colors['*'] = "\033[1;30;40m"; /* Gray cat face */
+ colors['%'] = "\033[1;35;45m"; /* Pink cheeks */
output = "██";
break;
case 5:
- colors[','] = "\033[0;34;44m"; /* Blue background */
- colors['.'] = "\033[1;37;47m"; /* White stars */
- colors['\''] = "\033[0;30;40m"; /* Black border */
- colors['@'] = "\033[1;37;47m"; /* Tan poptart */
- colors['$'] = "\033[1;35;45m"; /* Pink poptart */
- colors['-'] = "\033[1;31;41m"; /* Red poptart */
- colors['>'] = "\033[1;31;41m"; /* Red rainbow */
- colors['&'] = "\033[0;33;43m"; /* Orange rainbow */
- colors['+'] = "\033[1;33;43m"; /* Yellow Rainbow */
- colors['#'] = "\033[1;32;42m"; /* Green rainbow */
- colors['='] = "\033[1;34;44m"; /* Light blue rainbow */
- colors[';'] = "\033[0;34;44m"; /* Dark blue rainbow */
- colors['*'] = "\033[1;30;40m"; /* Gray cat face */
- colors['%'] = "\033[1;35;45m"; /* Pink cheeks */
+ colors[','] = "\033[0;34;44m"; /* Blue background */
+ colors['.'] = "\033[1;37;47m"; /* White stars */
+ colors['\''] = "\033[0;30;40m"; /* Black border */
+ colors['@'] = "\033[1;37;47m"; /* Tan poptart */
+ colors['$'] = "\033[1;35;45m"; /* Pink poptart */
+ colors['-'] = "\033[1;31;41m"; /* Red poptart */
+ colors['>'] = "\033[1;31;41m"; /* Red rainbow */
+ colors['&'] = "\033[0;33;43m"; /* Orange rainbow */
+ colors['+'] = "\033[1;33;43m"; /* Yellow Rainbow */
+ colors['#'] = "\033[1;32;42m"; /* Green rainbow */
+ colors['='] = "\033[1;34;44m"; /* Light blue rainbow */
+ colors[';'] = "\033[0;34;44m"; /* Dark blue rainbow */
+ colors['*'] = "\033[1;30;40m"; /* Gray cat face */
+ colors['%'] = "\033[1;35;45m"; /* Pink cheeks */
output = "\333\333";
break;
case 6:
- colors[','] = "::"; /* Blue background */
- colors['.'] = "@@"; /* White stars */
- colors['\''] = " "; /* Black border */
- colors['@'] = "##"; /* Tan poptart */
- colors['$'] = "??"; /* Pink poptart */
- colors['-'] = "<>"; /* Red poptart */
- colors['>'] = "##"; /* Red rainbow */
- colors['&'] = "=="; /* Orange rainbow */
- colors['+'] = "--"; /* Yellow Rainbow */
- colors['#'] = "++"; /* Green rainbow */
- colors['='] = "~~"; /* Light blue rainbow */
- colors[';'] = "$$"; /* Dark blue rainbow */
- colors['*'] = ";;"; /* Gray cat face */
- colors['%'] = "()"; /* Pink cheeks */
+ colors[','] = "::"; /* Blue background */
+ colors['.'] = "@@"; /* White stars */
+ colors['\''] = " "; /* Black border */
+ colors['@'] = "##"; /* Tan poptart */
+ colors['$'] = "??"; /* Pink poptart */
+ colors['-'] = "<>"; /* Red poptart */
+ colors['>'] = "##"; /* Red rainbow */
+ colors['&'] = "=="; /* Orange rainbow */
+ colors['+'] = "--"; /* Yellow Rainbow */
+ colors['#'] = "++"; /* Green rainbow */
+ colors['='] = "~~"; /* Light blue rainbow */
+ colors[';'] = "$$"; /* Dark blue rainbow */
+ colors['*'] = ";;"; /* Gray cat face */
+ colors['%'] = "()"; /* Pink cheeks */
always_escape = 1;
break;
default:
break;
}
+ /* Clear the screen */
printf("\033[H\033[2J\033[?25l");
+ /* Display the MOTD */
int countdown_clock = 5;
for (k = 0; k < countdown_clock; ++k) {
printf("\n\n\n");
@@ -333,9 +408,10 @@ ready:
fflush(stdout);
usleep(400000);
- printf("\033[H");
+ printf("\033[H"); /* Reset cursor */
}
+ /* Clear the screen again */
printf("\033[H\033[2J\033[?25l");
int playing = 1;
@@ -343,27 +419,36 @@ ready:
char last = 0;
size_t y, x;
while (playing) {
+ /* Render the frame */
for (y = MIN_ROW; y < MAX_ROW; ++y) {
for (x = MIN_COL; x < MAX_COL; ++x) {
if (always_escape) {
+ /* Text mode (or "Always Send Color Escapse") */
printf("%s", colors[frames[i][y][x]]);
} else {
if (frames[i][y][x] != last && colors[frames[i][y][x]]) {
+ /* Normal Mode, send escape (because the color changed) */
last = frames[i][y][x];
printf("%s%s", colors[frames[i][y][x]], output);
} else {
+ /* Same color, just send the output characters */
printf("%s", output);
}
}
}
+ /* End of row, send newline */
if (y != MAX_ROW - 1)
printf("\n");
}
+ /* Update frame crount */
++i;
if (!frames[i]) {
+ /* Loop animation */
i = 0;
}
+ /* Reset cursor */
printf("\033[H");
+ /* Wait */
usleep(90000);
}
return 0;