implemented simplest possible version of "more"

1 files changed, 75 insertions, 2 deletions

diff --git a/more.c b/more.c
index 11a3c2d..7dbe5f6 100644
--- a/more.c
+++ b/more.c
@@ -1,7 +1,15 @@
 /* See LICENSE file for copyright and license details. */
+#include <fcntl.h>
+#include <sys/stat.h>
+#include <unistd.h>
+#include <stdio.h>
 
 #include "util.h"
 
+#define COLUMNS 80
+#define ROWS 25
+#define BUFSIZE 10
+
 static void
 usage(void)
 {
@@ -11,12 +19,77 @@ usage(void)
 int
 main(int argc, char *argv[])
 {
-	int ret = 0;
+	int fd;
+	char c;
+	int col;
+	int row;
+	int buf[BUFSIZE];
 
 	ARGBEGIN {
 	default:
 		usage();
 	} ARGEND
+
+	if (argc < 1 && isatty(STDIN_FILENO))
+		usage();
+	
+	if (isatty(STDIN_FILENO)) {
+		if ((fd = open(*argv, O_RDONLY)) < 0) {
+			weprintf("open %s:", *argv);
+			return 0;
+			
+		}
+	} else {
+		fd = STDIN_FILENO;
+	}
+	
+	col = 0;
+	row = 0;
+	while (read(fd, &c, 1) != 0) {
+		switch (c) {
+			case '\r':
+				col = 0;
+				break;
+			
+			case '\n':
+				col = 0;
+				row++;
+				break;
+			
+			case '\t':
+				col = ((col+1) | 0x07)+1;
+				break;
+			
+			case '\b':
+				if (col>0) {
+					col--;
+				}
+				break;
+				
+			default:
+				col++;
+				break;
+		}
+		putchar(c);
+		
+		if (row<ROWS) {
+			continue;
+		}
+		
+		puts("--more--");
+		
+		if (read(STDIN_FILENO, &buf, BUFSIZE) < 0) {
+			goto END;
+		}
 		
-	return ret;
+		col = 0;
+		row = 0;		
+	}
+	
+END:
+	if (fd > STDERR_FILENO) {
+		close(fd);
+	}
+	
+	return 0;
 }