Add page.c, for paging log

1 files changed, 184 insertions, 0 deletions

diff --git a/page.c b/page.c
new file mode 100644
index 0000000..4e8216d
--- /dev/null
+++ b/page.c
@@ -0,0 +1,184 @@
+/* See LICENSE file for copyright and license details. */
+#include <stdlib.h>
+#include <stdio.h>
+#include <string.h>
+#include <curses.h>
+
+void freefilebuf(char **buffer, ssize_t cnt)
+{
+	if (!buffer || !cnt)
+		return;
+
+	while (cnt)
+		free(buffer[--cnt]);
+
+	free(buffer);
+}
+
+int readfile(FILE *fp, char ***buffer, ssize_t *count, int ncols)
+{
+	char **buf, **tmp;
+	char *line;
+	int ret;
+	size_t chunks, sz;
+	ssize_t cnt, len, cuts, clen;
+#define CHUNKS 128
+
+	if (!fp)
+		return -1;
+
+	buf = malloc(sizeof(char *) * CHUNKS);
+	if (buf == NULL) {
+		perror(NULL);
+		return -1;
+	}
+
+	ret = 0;
+	cnt = 0;
+	chunks = CHUNKS;
+
+	for (cnt = 0; ; cnt++) {
+		if (cnt == chunks-5) {
+			chunks += CHUNKS;
+			tmp = realloc(buf, chunks * sizeof(char *));
+			if (tmp == NULL) {
+				ret = -1;
+				break;
+			}
+			buf = tmp;
+		}
+		line = NULL;
+		sz = 0;
+		if ((len = getdelim(&line, &sz, '\n', fp)) == -1) {
+			if (ferror(fp))
+				ret = -1;
+			break;
+		}
+		line[--len] = '\0'; /* remove the newline */
+		if (len > ncols) {
+			char *p;
+			cuts = 0;
+			clen = len;
+			p = line;
+			while ((clen > 0) && (ret != -1)) {
+				buf[cnt+cuts] = strndup(p, (clen > ncols) ? ncols - 1 : clen);
+				p += ncols - 1;
+				clen -= ncols - 1;
+				cuts++;
+				if (cnt+cuts == chunks-5) {
+					chunks += CHUNKS;
+					tmp = realloc(buf, chunks * sizeof(char *));
+					if (tmp == NULL) {
+						ret = -1;
+						break;
+					}
+					buf = tmp;
+				}
+			}
+			cnt += (cuts - 1);
+			free(line);
+			if (ret == -1)
+				break;
+		}
+		else {
+			buf[cnt] = line;
+		}
+	}
+
+	if (ret == -1) {
+		perror(NULL);
+		freefilebuf(buf, cnt);
+	}
+	else {
+		*buffer = buf;
+		*count = cnt;
+	}
+
+	free(line);
+
+	return ret;
+}
+
+void displayfile(FILE *fp, long fpos, int r, int c, int y, int x)
+{
+	WINDOW *win;
+	char **lbuf;
+	int i, ch, inc, loc;
+	ssize_t n, ctop, start;
+
+	if (fseek(fp, fpos, SEEK_SET) == -1) {
+		perror(NULL);
+		return;
+	}
+
+	if ((readfile(fp, &lbuf, &n, c) == -1) || (n <= r)) {
+		freefilebuf(lbuf, n);
+		return;
+	}
+
+	inc = 0;
+	ctop = start = n - r;
+
+	win = newwin(r, c, y, x);
+	idlok(win, TRUE);
+	scrollok(win, TRUE);
+	wsetscrreg(win, 0, r-1);
+
+	for (i = 0; i < r && i < n; i++)
+		mvwaddnstr(win, i, 0, lbuf[ctop+i], c);
+	wrefresh(win);
+
+	while ((ch = getch()) != 'q') {
+		if (n <=r)
+			continue;
+		switch (ch) {
+			case 'f':
+				if (ctop + r >= n)
+					break;
+				ctop += r;
+				if (ctop > n - r)
+					ctop = (n - r);
+				break;
+			case 'b':
+				if (ctop == 0)
+					break;
+				ctop -= r;
+				if (ctop < 0)
+					ctop = 0;
+				break;
+			case 'j':
+				if (ctop + r >= n)
+					break;
+				inc = 1;
+				ctop++;
+				break;
+			case 'k':
+				if (ctop == 0)
+					break;
+				inc = -1;
+				ctop--;
+				break;
+			default:
+				break;
+		}
+		if (start != ctop) {
+			if (inc) {
+				loc = (inc < 0) ? 0 : r - 1;
+				wscrl(win, inc);
+				mvwaddnstr(win, loc, 0, lbuf[ctop+loc], c);
+				wrefresh(win);
+				inc = 0;
+			}
+			else if (start != ctop) {
+				wclear(win);
+				for (i = 0; i < r; i++)
+					mvwaddnstr(win, i, 0, lbuf[ctop+i], c);
+				wrefresh(win);
+			}
+			start = ctop;
+		}
+	}
+
+	freefilebuf(lbuf, n);
+	delwin(win);
+}