--- /dev/null
+#include <stdio.h>
+#include <stdlib.h>
+#include <unistd.h>
+#include <fcntl.h>
+#include <signal.h>
+#include <wait.h>
+
+#define EOR '\n'
+#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)
+
+
+void losepage(void)
+{
+ if(hp<cp)
+ bptr=page[incr(hp,PAGMAX)];
+}
+
+int ensure(void)
+{
+ for(;;) {
+ if(bptr<=bend)
+ return(BUFMAX-bend-1);
+ if(bptr-bend>=512)
+ return(512);
+ losepage();
+ }
+}
+
+
+void fillbuf(void)
+{
+ register int r;
+ ensure();
+ if(eof)
+ return;
+ r=read(file,&buf[bend],512);
+ if(r==-1)
+ return;
+ bend += r; bend &= BUFMAX-1;
+ if(r==0)
+ eof++;
+}
+
+int readchar(void)
+{
+ register char c;
+ if(bnxt==bend)
+ fillbuf();
+ if(eof)
+ return(-1);
+ c=buf[bnxt];
+ incr(bnxt,BUFMAX);
+ return(c);
+}
+
+void setpage(void)
+{
+ incr(cp,PAGMAX);
+ if(cp==hp)
+ incr(hp,PAGMAX);
+ page[cp]=bnxt;
+}
+
+void getpage(int i)
+{
+ if(i==0)
+ cp=hp;
+ else if(cp!=hp)
+ decr(cp,PAGMAX);
+ bnxt=page[cp];
+}
+
+
+int shell(void)
+{
+ 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(SIGCHLD, SIG_DFL);
+ 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);
+ }
+}
+
+void print(void)
+{
+ 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;
+ }
+ }
+ }
+}
+
+
+int main(int argc, char *argv[])
+{
+ int n=1;
+ if(argc<2)
+ print();
+ else {
+ while(argv[n] != NULL) {
+ if((file=open(argv[n],0))>=0) {
+ print();
+ close(file);
+ } else printf("pg: `%s' cannot open\n",argv[n]);
+ n++;
+ }
+ }
+ return 0;
+}
public / FUZIX.git / commitdiff