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/*
* view.c -- a silly little viewer program
*
* written by Eric S. Raymond <esr@snark.thyrsus.com> December 1994
* to test the scrolling code in ncurses.
*
* Takes a filename argument. It's a simple file-viewer with various
* scroll-up and scroll-down commands.
*
* n -- scroll one line forward
* p -- scroll one line back
*
* Either command accepts a numeric prefix interpreted as a repeat count.
* Thus, typing `5n' should scroll forward 5 lines in the file.
*
* The way you can tell this is working OK is that, in the trace file,
* there should be one scroll operation plus a small number of line
* updates, as opposed to a whole-page update. This means the physical
* scroll operation worked, and the refresh() code only had to do a
* partial repaint.
*/
#include <curses.h>
#include <stdlib.h>
#include <string.h>
#include <ctype.h>
#include <signal.h>
#define MAXLINES 256 /* most lines we can handle */
static void finish(int sig);
static char *lines[MAXLINES];
int main(int argc, char *argv[])
{
FILE *fp;
char buf[BUFSIZ];
int i;
char **lptr, **olptr;
#ifdef TRACE
trace(TRACE_UPDATE);
#endif
if (argc != 2) {
fprintf(stderr, "usage: view file\n");
exit(1);
} else if ((fp = fopen(argv[1], "r")) == (FILE *)NULL) {
perror(argv[1]);
exit(1);
}
(void) signal(SIGINT, finish); /* arrange interrupts to terminate */
(void) initscr(); /* initialize the curses library */
keypad(stdscr, TRUE); /* enable keyboard mapping */
(void) nonl(); /* tell curses not to do NL->CR/NL on output */
(void) cbreak(); /* take input chars one at a time, no wait for \n */
(void) noecho(); /* don't echo input */
scrollok(stdscr, TRUE);
/* slurp the file */
for (lptr = &lines[0]; fgets(buf, BUFSIZ, fp) != (char *)NULL; lptr++) {
if (lptr - lines >= MAXLINES) {
endwin();
(void) fprintf(stderr, "%s: %s is too large\n", argv[0], argv[1]);
exit(1);
}
buf[strlen(buf) - 1] = '\0';
*lptr = (char *)malloc((size_t)(COLS + 1));
(void) strncpy(*lptr, buf, (size_t)COLS);
(*lptr)[COLS] = '\0';
}
(void) fclose(fp);
lptr = lines;
for (;;) {
int n, c;
bool explicit;
for (i = 0; i < LINES; i++) {
move(i, 0);
clrtoeol();
if (lptr[i])
addstr(lptr[i]);
}
explicit = FALSE;
n = 0;
for (;;) {
c = getch();
if (isdigit(c))
n = 10 * n + (c - '0');
else
break;
}
if (!explicit && n == 0)
n = 1;
switch(c) {
case KEY_DOWN:
case 'n':
olptr = lptr;
for (i = 0; i < n; i++)
if (lptr + LINES < lines + MAXLINES && lptr[LINES + 1])
lptr++;
else
break;
wscrl(stdscr, lptr - olptr);
break;
case KEY_UP:
case 'p':
olptr = lptr;
for (i = 0; i < n; i++)
if (lptr > lines)
lptr--;
else
break;
wscrl(stdscr, lptr - olptr);
break;
default:
move (0,0);
clrtoeol ();
printw ("Invalid input: %c", c);
refresh ();
sleep (1);
}
}
finish(0); /* we're done */
}
static void finish(int sig)
{
endwin();
exit(sig != 0);
}
/* view.c ends here */
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