From fb0cdfe743869f6592090e441a071f0904a80634 Mon Sep 17 00:00:00 2001
From: tomsmeding <tom.smeding@gmail.com>
Date: Thu, 2 Mar 2017 21:23:39 +0100
Subject: Optimize terminal usage

The ^C-catching stuff will not work on windows; need to look into that
---
 main.cpp         |  22 ++++++--
 screenbuffer.cpp | 152 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 screenbuffer.h   |  24 +++++++++
 world.cpp        |  24 +++++++--
 world.h          |   4 +-
 5 files changed, 216 insertions(+), 10 deletions(-)
 create mode 100644 screenbuffer.cpp
 create mode 100644 screenbuffer.h

diff --git a/main.cpp b/main.cpp
index 3d4a048..d75c253 100644
--- a/main.cpp
+++ b/main.cpp
@@ -8,6 +8,7 @@
 #include <tuple>
 #include <cctype>
 #include <cassert>
+#include <signal.h>
 #include <sys/time.h>
 #include "params.h"
 #include "world.h"
@@ -210,6 +211,16 @@ string preprocess(istream &file){
 }
 
 
+static ScreenBuffer *sb;
+
+static void signalHandler(int sig){
+	if(sig==SIGINT){
+		sb->emergencyDeinit();
+		_exit(130);
+	}
+}
+
+
 int main(int argc,char **argv){
 	struct timeval tv;
 	gettimeofday(&tv,nullptr);
@@ -249,11 +260,14 @@ int main(int argc,char **argv){
 		}
 	}
 
-	world.print();
+	sb=new ScreenBuffer(SIZE*3,SIZE);
+	signal(SIGINT,signalHandler);
+	world.print(*sb);
 	for(int i=0;i<C::autoTimeout;i++){
-		world.tick();
 		usleep(3000);
-		cout<<"\x1B[2J\x1B[H";
-		world.print();
+		world.tick();
+		world.print(*sb);
+		sb->draw();
 	}
+	delete sb;
 }
diff --git a/screenbuffer.cpp b/screenbuffer.cpp
new file mode 100644
index 0000000..a382e82
--- /dev/null
+++ b/screenbuffer.cpp
@@ -0,0 +1,152 @@
+#define _GNU_SOURCE
+#include <iostream>
+#include <cstdarg>
+#include <cstdlib>
+#include <cstring>
+#include <cassert>
+#include <unistd.h>
+#include "screenbuffer.h"
+
+using namespace std;
+
+
+static void initTerminal(){
+	cout<<"\x1B[?1049h"  // start alternate screen
+	      "\x1B[2J"  // clear screen
+	      "\x1B[H"  // move to top left
+	    <<flush;
+}
+
+static void deinitTerminal(){
+	cout<<"\x1B[?1049l"  // end alternate screen
+	    <<flush;
+}
+
+
+ScreenBuffer::ScreenBuffer(int W,int H)
+		:W(W),H(H){
+	screen=new char[W*H];
+	prevscreen=new char[W*H];
+	memset(screen,' ',W*H);
+	memset(prevscreen,' ',W*H);
+	initTerminal();
+}
+
+ScreenBuffer::~ScreenBuffer(){
+	delete[] screen;
+	delete[] prevscreen;
+	deinitTerminal();
+}
+
+void ScreenBuffer::moveto(int x,int y){
+	assert(x>=0&&x<W&&y>=0&&y<H);
+	curx=x;
+	cury=y;
+}
+
+void ScreenBuffer::printstr(const char *buf){
+	int basex=curx;
+	for(int i=0;buf[i];i++){
+		if(buf[i]!='\n'){
+			if(curx==W){
+				if(cury==H-1){
+					curx--;
+					break;
+				}
+				curx=basex;
+				cury++;
+			}
+			screen[W*cury+curx]=buf[i];
+			curx++;
+		} else {
+			if(cury==H-1)break;
+			curx=basex;
+		}
+	}
+
+	if(curx==W){
+		if(cury==H-1){
+			curx--;
+		} else {
+			curx=basex;
+			cury++;
+		}
+	}
+}
+
+__attribute__((format (printf, 2, 3)))
+int ScreenBuffer::printf(const char *format,...){
+	va_list ap;
+	va_start(ap,format);
+	char *buf;
+	int ret=vasprintf(&buf,format,ap);
+	va_end(ap);
+	assert(buf);
+
+	printstr(buf);
+
+	free(buf);
+	return ret;
+}
+
+__attribute__((format (printf, 4, 5)))
+int ScreenBuffer::mvprintf(int x,int y,const char *format,...){
+	moveto(x,y);
+
+	va_list ap;
+	va_start(ap,format);
+	char *buf;
+	int ret=vasprintf(&buf,format,ap);
+	va_end(ap);
+	assert(buf);
+
+	printstr(buf);
+
+	free(buf);
+	return ret;
+}
+
+void ScreenBuffer::draw(){
+	bool changed[W*H];
+	for(int i=0;i<W*H;i++){
+		changed[i]=screen[i]!=prevscreen[i];
+	}
+	for(int y=0;y<H;y++){
+		for(int x=1;x<W-1;x++){
+			changed[W*y+x]|=changed[W*y+x-1]&changed[W*y+x+1];
+		}
+	}
+
+	bool prepped=false;
+
+	for(int y=0;y<H;y++){
+		bool needtomove=true;
+		for(int x=0;x<W;x++){
+			if(!changed[W*y+x]){
+				needtomove=true;
+				continue;
+			}
+			if(!prepped){
+				cout<<"\x1B[?25l";  // invisible cursor
+				prepped=true;
+			}
+			if(needtomove){
+				cout<<"\x1B["<<y+1<<';'<<x+1<<'H';
+				needtomove=false;
+			}
+			cout.put(screen[W*y+x]);
+		}
+	}
+	if(prepped){
+		cout<<"\x1B[?12;25h"  // visible cursor
+		    <<"\x1B["<<H<<';'<<W<<'H'  // move past screen
+		    <<flush;
+	}
+
+	memcpy(prevscreen,screen,W*H);
+}
+
+void ScreenBuffer::emergencyDeinit(){
+	static const char *str="\n\x1B[?1049l\x1B[12;25h^C\n";
+	write(1,str,strlen(str));
+}
diff --git a/screenbuffer.h b/screenbuffer.h
new file mode 100644
index 0000000..49cc5c5
--- /dev/null
+++ b/screenbuffer.h
@@ -0,0 +1,24 @@
+#pragma once
+
+using namespace std;
+
+
+class ScreenBuffer{
+	int W,H;
+	char *prevscreen,*screen;
+	int curx=0,cury=0;
+
+	void printstr(const char *buf);
+
+public:
+	ScreenBuffer(int W,int H);
+	~ScreenBuffer();
+
+	void moveto(int x,int y);
+	int printf(const char *format,...) __attribute__((format (printf, 2, 3)));
+	int mvprintf(int x,int y,const char *format,...) __attribute__((format (printf, 4, 5)));
+
+	void draw();
+
+	void emergencyDeinit();
+};
diff --git a/world.cpp b/world.cpp
index b74e7cb..0af24a2 100644
--- a/world.cpp
+++ b/world.cpp
@@ -316,14 +316,28 @@ Robot* World::targetbot(const Robot *r){
 	return *targetbotptr(r);
 }
 
-void World::print() const {
+void World::print(ostream &os) const {
 	for(int y=0;y<SIZE;y++){
 		for(int x=0;x<SIZE;x++){
-			if(board[y][x]==nullptr)cout<<"..";
-			else cout<<string(2,"^>v<"[board[y][x]->heading%4]);
-			cout<<' ';
+			if(board[y][x]==nullptr)os<<"..";
+			else os<<string(2,"^>v<"[board[y][x]->heading%4]);
+			os<<' ';
+		}
+		os<<endl;
+	}
+}
+
+void World::print(ScreenBuffer &sb) const {
+	for(int y=0;y<SIZE;y++){
+		sb.moveto(0,y);
+		for(int x=0;x<SIZE;x++){
+			if(board[y][x]==nullptr)sb.printf("..");
+			else {
+				char c="^>v<"[board[y][x]->heading%4];
+				sb.printf("%c%c",c,c);
+			}
+			sb.printf(" ");
 		}
-		cout<<endl;
 	}
 }
 
diff --git a/world.h b/world.h
index e964e8d..caaa4f0 100644
--- a/world.h
+++ b/world.h
@@ -6,6 +6,7 @@
 #include <vector>
 #include <cstdint>
 #include "params.h"
+#include "screenbuffer.h"
 
 using namespace std;
 
@@ -100,7 +101,8 @@ public:
 	void tick();
 	Robot* targetbot(const Robot *r);
 
-	void print() const;
+	void print(ostream &os) const;
+	void print(ScreenBuffer &sb) const;
 };
 
 
-- 
cgit v1.2.3-70-g09d2