add pager

1 files changed, 109 insertions, 0 deletions

diff --git a/core/pager.c b/core/pager.c
new file mode 100644
index 0000000..cda5300
--- /dev/null
+++ b/core/pager.c
@@ -0,0 +1,109 @@
+#include "../lib/container/container.h"
+#include "../lib/io/io.h"
+#include "../lib/aec/aec.h"
+#include "../lib/tctl/tctl.h"
+#include "../lib/cstr/cstr.h"
+
+
+#define BUFFER_SIZE 128
+char buf[BUFFER_SIZE];
+container_t *string;
+
+
+u64 scroll = 0;
+u64 maxscroll = 0;
+u64 num_lines = 0;
+termios_t original;
+termios_t current;
+
+
+void scroll_delta(int d)
+{
+	scroll += d;
+
+	if ((i64)(scroll) < 0) {
+		scroll = 0;
+	} else if (scroll > maxscroll) {
+		scroll = maxscroll;
+	}
+}
+
+void draw_screen()
+{
+	window_size_t ws = tctl_get_window_size();
+	clear_screen();
+	move_cursor(0, 0);
+
+	substr_t line = getline(string->data, scroll);
+
+	for (int i = 0; i < ws.height - 1 && line.begin; ++i) {
+		write(STDOUT_FD, line.begin, line.end - line.begin + 1);
+		line = nextline(line);
+	}
+
+	move_cursor(0, ws.height);
+	wstdf("%S Line: %i/%i %S", SGR_REVERSE, scroll + 1, num_lines, SGR_REVERSE_OFF);
+
+	flush(STDOUT_FD);
+}
+
+
+int main(int argc, const char **argv)
+{
+	if (argc != 1) {
+		wf(STDERR_FD, "pager\n");
+		return -1;
+	}
+
+	if (!isatty()) {
+		wf(STDERR_FD, "error: stdout is no tty! exiting.\n");
+		return -1;
+	}
+
+	string = new_container(sizeof(char));
+	u64 size;
+
+	while ((size = rstd(buf, BUFFER_SIZE))) {
+		container_append(string, buf, size);
+	}
+
+	container_push(string, 0);
+
+	tcgetattr(STDOUT_FD, &original);
+	current = original;
+	setcanonical(&current, 0);
+	setecho(&current, 0);
+	cursor_enabled(0);
+	tcsetattr(STDOUT_FD, &current);
+
+
+	char key;
+	int running = 1;
+	window_size_t ws = tctl_get_window_size();
+	num_lines = number_of_lines(string->data);
+	maxscroll = num_lines < ws.height ? 0 : num_lines - ws.height + 1;
+
+	draw_screen();
+
+	while (running && read(STDERR_FD, &key, 1) == 1) {
+		switch (key) {
+			case 'j': scroll_delta(1);    break;
+			case 'k': scroll_delta(-1);   break;
+			case 'g': scroll = 0;         break;
+			case 'G': scroll = maxscroll; break;
+
+			case 'q':
+			case '\033': running = 0; break;
+		}
+
+		draw_screen();
+	}
+
+	tcsetattr(STDOUT_FD, &original);
+	cursor_enabled(1);
+
+	clear_screen();
+	move_cursor(0, 0);
+
+	return 0;
+}