X-Git-Url: http://git.mutantstargoat.com/user/nuclear/?a=blobdiff_plain;f=src%2Fdos%2Flogger.c;h=197677037eb5aa4c34ddab1b6fcc21f612beac81;hb=HEAD;hp=73860e3cb44428fd94b0ba085d147100de9658de;hpb=8a64d603ee67cd98070360b40938e123ea845154;p=dosdemo

diff --git a/src/dos/logger.c b/src/dos/logger.c
index 73860e3..1976770 100644
--- a/src/dos/logger.c
+++ b/src/dos/logger.c
@@ -1,46 +1,68 @@
-/*
-colcycle - color cycling image viewer
-Copyright (C) 2016  John Tsiombikas <nuclear@member.fsf.org>
-
-This program is free software: you can redistribute it and/or modify
-it under the terms of the GNU General Public License as published by
-the Free Software Foundation, either version 3 of the License, or
-(at your option) any later version.
-
-This program is distributed in the hope that it will be useful,
-but WITHOUT ANY WARRANTY; without even the implied warranty of
-MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
-GNU General Public License for more details.
-
-You should have received a copy of the GNU General Public License
-along with this program.  If not, see <http://www.gnu.org/licenses/>.
-*/
 #include <stdio.h>
-#include <stdarg.h>
+#include <string.h>
+#include <errno.h>
+#include <unistd.h>
+#include <fcntl.h>
 #include "logger.h"
 
-#define LOGFNAME	"demo.log"
+static int logfd = -1, orig_fd1 = -1;
 
-static FILE *logfile;
+int init_logger(const char *fname)
+{
+	if(logfd != -1) return -1;
+
+	if((logfd = open(fname, O_CREAT | O_WRONLY | O_TRUNC, 0644)) == -1) {
+		fprintf(stderr, "init_logger: failed to open %s: %s\n", fname, strerror(errno));
+		return -1;
+	}
+
+	orig_fd1 = dup(1);
+	close(1);
+	close(2);
+	dup(logfd);
+	dup(logfd);
+	return 0;
+}
 
-void logger_output(FILE *fp)
+void stop_logger(void)
 {
-	if(logfile) fclose(logfile);
-	logfile = fp;
+	if(logfd >= 0) {
+		close(logfd);
+		logfd = -1;
+	}
+	if(orig_fd1 >= 0) {
+		close(1);
+		close(2);
+		dup(orig_fd1);
+		dup(orig_fd1);
+		orig_fd1 = -1;
+	}
 }
 
-void printlog(const char *fmt, ...)
+int print_tail(const char *fname)
 {
-	va_list ap;
+	FILE *fp;
+	char buf[64];
+	long lineoffs[16];
+	int wr, rd, c;
 
-	if(!logfile) {
-		if(!(logfile = fopen(LOGFNAME, "w"))) {
-			return;
+	if(!(fp = fopen(fname, "r"))) {
+		return -1;
+	}
+	wr = rd = 0;
+	lineoffs[wr++] = 0;
+	while(fgets(buf, sizeof buf, fp)) {
+		lineoffs[wr] = ftell(fp);
+		wr = (wr + 1) & 0xf;
+		if(wr == rd) {
+			rd = (rd + 1) & 0xf;
 		}
-		setvbuf(logfile, 0, _IOLBF, 0);
 	}
 
-	va_start(ap, fmt);
-	vfprintf(logfile, fmt, ap);
-	va_end(ap);
+	fseek(fp, lineoffs[rd], SEEK_SET);
+	while((c = fgetc(fp)) != -1) {
+		fputc(c, stdout);
+	}
+	fclose(fp);
+	return 0;
 }