Status update, November 2020 November 15, 2020 on Drew DeVault's blog

#include <poll.h>
#include <signal.h>
#include <stdint.h>
#include <stdio.h>
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
#include <sys/mman.h>
#include <sys/socket.h>
#include <sys/un.h>
#include <time.h>
#include <unistd.h>

	typedef int16_t i16; typedef int32_t i32; typedef uint16_t u16;
   typedef uint32_t u32; typedef uint8_t u8; typedef int I; typedef size_t S;
	  typedef struct{int b;u32 a,c,d;char*e;i32 x,y,w,h,s,fmt;}O;
	       typedef struct{char*a;u32 b;I(*c)(I,I,u32,u16);}G;

	  struct pollfd fds[33];char a[0xFFFF];I b=0,c=1,d=-1;u32 e=0;
			      O f[128][128];G g[];

#define AR I z,I y,u32 x,u16 c
#define SN(n) (((n)%4)==0?(n):(n)+(4-((n)%4)))

void u8w(FILE*f,u32 ch){char b[4];for (I i=2;i>0;--i){b[i]=(ch&0x3f)|0x80;ch>>=6
;}b[0]=ch|0xE0;fwrite(b,1,3,f);}void xrgb(u32*data,i32 w,i32 h,i32 s){struct
winsize sz;ioctl(0,TIOCGWINSZ,&sz);--sz.ws_row;printf("\x1b[H\x1b[2J\x1b[3J");
for(I y=0;y<sz.ws_row;++y){for(I x=0;x<sz.ws_col;++x){I i=0;u32 c = 0x2800;const
I f[]={0,3,1,4,2,5,6,7};for(I my=0;my<4;++my)for(I mx=0;mx<2;++mx){u32 p=data[((
y*4+my)*h)/(sz.ws_row*4)*(s/4)+((x*2+mx)*w)/(sz.ws_col*2)];u8 avg=((p&0xFF)+((p
>>8)&0xFF)+((p>>16)&0xFF))/3;if(avg>0x80)c|=1<<f[i++];}u8w(stdout,c);}putchar(
'\n');}fflush(stdout);}O*ao(I z,u32 y,I x){for(S i=0;i<128;++i)if(f[z][i].a==0){
f[z][i].a=y;f[z][i].b=x;return &f[z][i];}return 0;}O*go(I z,u32 y){for(S i=0;i<
128;++i)if(f[z][i].a==y)return &f[z][i];return 0;}void wh(I z,i32 y,i16 x, i16 w
){write(z,&y,4);i32 u=((w+8)<<16)|x;write(z,&u,4);}void ws(I z,char*y){i32 l=
strlen(y)+1;write(z,&l,4);l=SN(l);write(z,y,l);}I rs(I z){u32 l;read(z,&l,4);l=
SN(l);read(z,a,l);return l+4;}I ga(I z,I y,u32 x,u16 w){u32 b,u,t,s=0;read(y,&u,
4);I sz=rs(y)+12;read(y,&b,4);read(y,&t,4);--u;ao(z,t,u);switch(u){case 1:++s;wh
(y,t,0,4);write(y,&s,4);--s;break;case 6:s=0;break;default:return sz;}wh(y,t,0,4
);write(y,&s,4);return sz;}I gb(AR){u32 w,u;read(y,&w,4);I t=d;d=-1;read(y,&u,4);
O *o=ao(z,w,15);o->e=mmap(0,u,PROT_READ,MAP_PRIVATE,t,0);return 8;}I gc(AR){u32
w;read(y,&w,4);ao(z,w,8+c);return 4;}I gd(AR){O*o,*r,*t;i32 u,w;switch(c){case 1
:read(y,&u,4);read(y,&w,4);read(y,&w,4);go(z,x)->d=u;if(!u==0){O *b=go(z,u);xrgb
((u32*)b->e,b->w,b->h,b->s);}wh(y,u,0,0);return 12;case 2:read(y,&u,4);read(y, &
u, 4);read(y, &u, 4);read(y, &u, 4);return 16;case 3:read(y,&w,4);struct timespec
ts={.tv_sec=0,.tv_nsec=1.6e6};nanosleep(&ts,0);wh(y,w,0,4);write(y,&w,4);return
4;case 6:o=go(z,x);r=go(z,o->c);if(r&&r->b==12){t=go(z,r->c);if(t->b==13){u32
s=0; wh(y,t->a,0,12);write(y,&s,4);write(y,&s,4);write(y,&s,4);}wh(y,r->a,0,4);
write(y,&e,4);++e;}break;}return 0;}I ge(AR){u32 w,u;if(c==2){read(y,&w,4);read(
y,&u,4);O*o=ao(z,w,12);o->d=u;go(z,u)->c=w;return 8;}return 0;}I gf(AR){u32 w,ae
;switch(c){case 1:read(y,&w,4);O*obj=ao(z,w,13);obj->d=x;go(z,x)->c=w;return 4;
case 4:read(y,&ae,4);return 4;}return 0;}I gg(AR){I sz;switch(c){case 2:sz=rs(y)
;return sz;}return 0;}I gh(AR){i32 w,u;switch(c){case 0:read(y,&w,4);read(y,&u,4
);O*b=ao(z,w,10);b->e=&go(z,x)->e[u];read(y,&b->w,4);read(y,&b->h,4);read(y,&b->
                  s,4);read(y,&b->fmt,4);return 24;}return 0;}

G g[]={{0,0,ga},{"wl_shm",1,gb},{"wl_compositor",1,gc},{"wl_subcompositor",1,0},
{"wl_data_device_manager",3,0},{"wl_output",3,0},{"wl_seat",7,0},{"xdg_wm_base",
2,ge},{0,0,gd},{0,0,0},{0,0,0},{0,0,0},{0,0,gf},{0,0,gg},{0,0,0},{0,0,gh}};

void gi(AR){u32 w;switch(c){case 0:read(y,&w,4);wh(y,w,0,4);write(y,&w,4);break;
case 1:read(y,&w,4);ao(z,w,0);for(S i=0;i<sizeof(g)/sizeof(g[0]);){G*z=&g[i++];
if(!z->b)continue;I gl=strlen(z->a)+1;wh(y,w,0,4+SN(gl)+4+4);write(y,&i,4);ws(y,
                z->a);write(y,&z->b,4);}break;}}void si(){c=0;}

I main(I _1,char**_2){I z=socket(AF_UNIX,SOCK_STREAM,0);struct sockaddr_un y={.
sun_family=AF_UNIX};char *x=getenv("XDG_RUNTIME_DIR");if(!x)x="/tmp";do{sprintf(
 y.sun_path,"%s/wayland-%d",x,c++);}while(access(y.sun_path,F_OK)==0);bind(z, (
struct sockaddr *)&y,sizeof(y));listen(z,3);for(S i=0;i<sizeof(fds);++i){fds[i].
events=POLLIN|POLLHUP;fds[i].revents=0;fds[i].fd=0;}fds[b++].fd=z;signal(SIGINT,
si);memset(&f,0,sizeof(f));while(poll(fds,b,-1)!=-1&&c){if(fds[0].revents){I u=
accept(z,0,0);fds[b++].fd=u;}for(I i=1;i<b;++i){if(fds[i].revents&POLLHUP){
memmove(&fds[i],&fds[i+1],32-i);memset(f[i-1],0,128*sizeof(**f));--b;continue;}
else if(!fds[i].revents){continue;}I u=i-1;I t=fds[i].fd;u32 s,r;char q[
CMSG_SPACE(8)];struct cmsghdr *p;struct iovec n={.iov_base=&s,.iov_len=4};struct
msghdr m={0};m.msg_iov=&n;m.msg_iovlen=1;m.msg_control=q;m.msg_controllen=sizeof
(q);recvmsg(t,&m,0);p=CMSG_FIRSTHDR(&m);if(p){d=*(I *)CMSG_DATA(p);}read(t,&r,4)
;u16 o=((r>>16)&0xFFFF)-8,c=r&0xFFFF;if(s==1){gi(u,t,s,c);}else{for(S j=0;j<128;
++j){if(f[u][j].a==s&&g[f[u][j].b].c){o-=g[f[u][j].b].c(u,t,s,c);break;}}if(o>0)
                     {read(t,a,o);}}}}unlink(y.sun_path);}