[unix-history] / usr / src / cmd / pg.c

#include <stdio.h>

#define NL '\n'
#define CLEAR 014
#define HOME 031
#define BACK 037
#define BUFMAX 16384
#define PAGMAX 64

int file;
int cp, hp;
int page[PAGMAX];
int eof;

char buf[BUFMAX];
int bptr, bnxt, bend;


#define incr(a,b) (a++, a&=b-1)
#define decr(a,b) (a--, a&=b-1)


main(argc,argv)
char *argv[];
{
	int n=1;
	if(argc<2)
		print();
	else {
		while(argv[n]!=-1) {
			if((file=open(argv[n],0))>=0) {
				print();
				close(file);
			} else	printf("dk: `%s' cannot open\n",argv[n]);
			n++;
		}
	}
}

print()
{
	register int nlc;
	char buf[2];

	hp=0; cp=0;
	bptr=bnxt=bend=0;
	putchar(CLEAR);
	for(;;) {
		setpage();
		nlc=0;
		putchar(BACK);
		while(nlc<20) {
			char c;
			c = readchar();
			if(eof)
				return;
			if(c==NL) nlc++;
			putchar(c);
		}
		while(read(2,buf,1)==1 && buf[0]!=NL) {
			switch(buf[0]) {
				case '/':
				case HOME:
					putchar(CLEAR);
					getpage(0);
					break;
				case '-':
				case BACK:
					getpage(-1);
					putchar(CLEAR);
					break;
				case '!':
					shell(); buf[0]=NL; break;
			}
		}
	}
}


#include <signal.h>
#define EOR '\n'
shell()
{
	int rc, status, unixpid;
	if( (unixpid=fork())==0 ) {
		close(0); dup(2);
		execl("/bin/sh", "sh", "-t", 0);
		exit(255);
	}
	else if(unixpid == -1)
		return(0);
	else{	signal(SIGINT,SIG_IGN); signal(SIGQUIT,SIG_IGN);
		while( (rc = wait(&status)) != unixpid && rc != -1 ) ;
		signal(SIGINT,SIG_DFL); signal(SIGQUIT,SIG_DFL);
		return(1);
	}
}

readchar()
{
	register char c;
	if(bnxt==bend)
		fillbuf();
	if(eof)
		return(-1);
	c=buf[bnxt];
	incr(bnxt,BUFMAX);
	return(c);
}

fillbuf()
{
	register int r;
	register int len;
	ensure();
	if(eof)
		return;
	r=read(file,&buf[bend],512);
	if(r==-1)
		return;
	bend += r; bend &= BUFMAX-1;
	if(r==0)
		eof++;
	return;
}

ensure()
{
	for(;;) {
		if(bptr<=bend)
			return(BUFMAX-bend-1);
		if(bptr-bend>=512)
			return(512);
		losepage();
	}
}

losepage()
{
	if(hp<cp)
		bptr=page[incr(hp,PAGMAX)];
}

setpage()
{
	incr(cp,PAGMAX);
	if(cp==hp)
		incr(hp,PAGMAX);
	page[cp]=bnxt;
}

getpage(i)
{
	if(i==0)
		cp=hp;
	else	if(cp!=hp)
			decr(cp,PAGMAX);
	bnxt=page[cp];
}
Commit	Line	Data
3b600ead TL	1	#include <stdio.h>
	2
	3	#define NL '\n'
	4	#define CLEAR 014
	5	#define HOME 031
	6	#define BACK 037
	7	#define BUFMAX 16384
	8	#define PAGMAX 64
	9
	10	int file;
	11	int cp, hp;
	12	int page[PAGMAX];
	13	int eof;
	14
	15	char buf[BUFMAX];
	16	int bptr, bnxt, bend;
	17
	18
	19	#define incr(a,b) (a++, a&=b-1)
	20	#define decr(a,b) (a--, a&=b-1)
	21
	22
	23	main(argc,argv)
	24	char *argv[];
	25	{
	26	int n=1;
	27	if(argc<2)
	28	print();
	29	else {
	30	while(argv[n]!=-1) {
	31	if((file=open(argv[n],0))>=0) {
	32	print();
	33	close(file);
	34	} else printf("dk: `%s' cannot open\n",argv[n]);
	35	n++;
	36	}
	37	}
	38	}
	39
	40	print()
	41	{
	42	register int nlc;
	43	char buf[2];
	44
	45	hp=0; cp=0;
	46	bptr=bnxt=bend=0;
	47	putchar(CLEAR);
	48	for(;;) {
	49	setpage();
	50	nlc=0;
	51	putchar(BACK);
	52	while(nlc<20) {
	53	char c;
	54	c = readchar();
	55	if(eof)
	56	return;
	57	if(c==NL) nlc++;
	58	putchar(c);
	59	}
	60	while(read(2,buf,1)==1 && buf[0]!=NL) {
	61	switch(buf[0]) {
	62	case '/':
	63	case HOME:
	64	putchar(CLEAR);
65	getpage(0);
66	break;
67	case '-':
68	case BACK:
69	getpage(-1);
70	putchar(CLEAR);
71	break;
72	case '!':
73	shell(); buf[0]=NL; break;
74	}
75	}
76	}
77	}
78
79
80	#include <signal.h>
81	#define EOR '\n'
82	shell()
83	{
84	int rc, status, unixpid;
85	if( (unixpid=fork())==0 ) {
86	close(0); dup(2);
87	execl("/bin/sh", "sh", "-t", 0);
88	exit(255);
89	}
90	else if(unixpid == -1)
91	return(0);
92	else{ signal(SIGINT,SIG_IGN); signal(SIGQUIT,SIG_IGN);
93	while( (rc = wait(&status)) != unixpid && rc != -1 ) ;
94	signal(SIGINT,SIG_DFL); signal(SIGQUIT,SIG_DFL);
95	return(1);
96	}
97	}
98
99	readchar()
100	{
101	register char c;
102	if(bnxt==bend)
103	fillbuf();
104	if(eof)
105	return(-1);
106	c=buf[bnxt];
107	incr(bnxt,BUFMAX);
108	return(c);
109	}
110
111	fillbuf()
112	{
113	register int r;
114	register int len;
115	ensure();
116	if(eof)
117	return;
118	r=read(file,&buf[bend],512);
119	if(r==-1)
120	return;
121	bend += r; bend &= BUFMAX-1;
122	if(r==0)
123	eof++;
124	return;
125	}
126
127	ensure()
128	{
129	for(;;) {
130	if(bptr<=bend)
131	return(BUFMAX-bend-1);
132	if(bptr-bend>=512)
133	return(512);
134	losepage();
135	}
136	}
137
138	losepage()
139	{
140	if(hp<cp)
141	bptr=page[incr(hp,PAGMAX)];
142	}
143
144	setpage()
145	{
146	incr(cp,PAGMAX);
147	if(cp==hp)
148	incr(hp,PAGMAX);
149	page[cp]=bnxt;
150	}
151
152	getpage(i)
153	{
154	if(i==0)
155	cp=hp;
156	else if(cp!=hp)
157	decr(cp,PAGMAX);
158	bnxt=page[cp];
159	}