add pager

7 files changed, 220 insertions, 8 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;
+}
diff --git a/lib/cstr/cstr.c b/lib/cstr/cstr.c
index f464cf3..9f4ad6f 100644
--- a/lib/cstr/cstr.c
+++ b/lib/cstr/cstr.c
@@ -175,6 +175,50 @@ u64 strip_cstr(char *cstr, char strip)
 	return strip_front(cstr, strip) + strip_back(cstr, strip);
 }
 
+
+u64 number_of_lines(const char *cstr)
+{
+	u64 lines = 0;
+
+	while (*cstr) {
+		if (*cstr == '\n') ++lines;
+		++cstr;
+	}
+
+	return lines;
+}
+
+
+substr_t getline(const char *cstr, u64 n)
+{
+	substr_t line;
+	line.begin = (char *)cstr;
+	line.end = line.begin;
+
+	while (*line.end && *line.end != '\n') ++line.end;
+
+	for (int i = 0; i < n; ++i)
+		line = nextline(line);
+
+	return line;
+}
+
+
+substr_t nextline(substr_t line)
+{
+	if (!(*line.end || *(line.end + 1))) {
+		line.begin = 0;
+		line.end = 0;
+		return line;
+	}
+
+	line.begin = ++line.end;
+
+	while (*line.end && *line.end != '\n') ++line.end;
+
+	return line;
+}
+
 /* DOC
  * @type function
  * @name string_utf8_length
@@ -272,6 +316,12 @@ void u64_to_cstr(u64 n, char *cstr, u64 length)
 		n /= 10;
 	}
 
+	if (p == cstr + length - 1) {
+		*(p--) = '0';
+	}
+
+	*p = 0;
+
 	d = p - cstr + 1;
 
 	for (i = 0; i < length - d; ++i)
diff --git a/lib/cstr/cstr.h b/lib/cstr/cstr.h
index 80dc359..ce27eb0 100644
--- a/lib/cstr/cstr.h
+++ b/lib/cstr/cstr.h
@@ -3,6 +3,11 @@
 
 #include "../sys/sizes.h"
 
+typedef struct {
+	char *begin;
+	char *end;
+} substr_t;
+
 u64        cstr_length(const char *);
 i8         cstr_compare(const char *a, const char *b);
 u64        cstr_split(char *cstr, char split);
@@ -10,6 +15,10 @@ const char *next_split(const char *previous);
 u64        strip_front(char *cstr, char strip);
 u64        strip_back(char *cstr, char strip);
 u64        strip_cstr(char *cstr, char strip);
+u64        number_of_lines(const char *cstr);
+
+substr_t   getline(const char *cstr, u64 n);
+substr_t   nextline(substr_t line);
 
 u64 cstr_utf8_length(const char *);
 u8  next_utf8(const char **);
diff --git a/lib/io/io.c b/lib/io/io.c
index 7dee314..57cfd05 100644
--- a/lib/io/io.c
+++ b/lib/io/io.c
@@ -15,9 +15,9 @@ void wstd(const char *buf)
 }
 
 
-void rstd(char *buf, unsigned long count)
+unsigned long rstd(char *buf, unsigned long count)
 {
-	read(STDIN_FD, buf, count);
+	return read(STDIN_FD, buf, count);
 }
 
 
@@ -26,6 +26,7 @@ void wf(unsigned int fd, char *buf)
 	write(fd, buf, cstr_length(buf));
 }
 
+
 void wstdf__(const char *buf, const void **args)
 {
 	wff__(STDOUT_FD, buf, args);
diff --git a/lib/io/io.h b/lib/io/io.h
index c373cd0..ac25e87 100644
--- a/lib/io/io.h
+++ b/lib/io/io.h
@@ -3,9 +3,9 @@
 
 #include "../sys/io.h"
 
-void wstd(const char *buf);
-void rstd(char *buf, unsigned long count);
-void wf(unsigned int fd, char *buf);
+void          wstd(const char *buf);
+unsigned long rstd(char *buf, unsigned long count);
+void          wf(unsigned int fd, char *buf);
 
 void wstdf__(const char *buf, const void **args);
 void wff__(unsigned int fd, const char *buf, const void **args);
diff --git a/lib/tctl/tctl.c b/lib/tctl/tctl.c
index 187d1a9..d54f2dd 100644
--- a/lib/tctl/tctl.c
+++ b/lib/tctl/tctl.c
@@ -4,6 +4,10 @@
 #define GET_WIN_SIZE 0x5413
 #define SET_WIN_SIZE 0x5414
 #define TC_GET_ATTR  0x5401
+#define TC_SET_ATTR  0x5402
+#define FD_FLUSH     0x000b
+#define ICANON       000002
+#define ECHO         000010
 
 window_size_t tctl_get_window_size()
 {
@@ -24,3 +28,39 @@ int isatty()
 	termios_t term;
 	return ioctl(1, TC_GET_ATTR, &term) == 0;
 }
+
+
+int tcgetattr(int fd, termios_t *termios)
+{
+	return ioctl(fd, TC_GET_ATTR, termios);
+}
+
+
+void tcsetattr(int fd, termios_t *termios)
+{
+	ioctl(fd, TC_SET_ATTR, termios);
+}
+
+
+void setcanonical(termios_t *term, int is_canonical)
+{
+	if (is_canonical)
+		term->c_lflag |= ICANON;
+	else
+		term->c_lflag &= ~ICANON;
+}
+
+
+void setecho(termios_t *term, int is_echo)
+{
+	if (is_echo)
+		term->c_lflag |= ECHO;
+	else
+		term->c_lflag &= ~ECHO;
+}
+
+
+void flush(unsigned int fd)
+{
+	ioctl(fd, FD_FLUSH, 0);
+}
diff --git a/lib/tctl/tctl.h b/lib/tctl/tctl.h
index bdcdb66..d16c9eb 100644
--- a/lib/tctl/tctl.h
+++ b/lib/tctl/tctl.h
@@ -14,13 +14,16 @@ typedef struct {
 	unsigned int  c_cflag;
 	unsigned int  c_lflag;
 	unsigned char c_line;
-	unsigned char c_cc[32];
-	unsigned int  c_ispeed;
-	unsigned int  c_ospeed;
+	unsigned char c_cc[19];
 } termios_t;
 
 window_size_t tctl_get_window_size();
 void          tctl_set_window_size(window_size_t size);
 int           isatty();
+int           tcgetattr(int fd, termios_t *termios);
+void          tcsetattr(int fd, termios_t *termios);
+void          setcanonical(termios_t *term, int is_canonical);
+void          setecho(termios_t *term, int is_echo);
+void          flush(unsigned int fd);
 
 #endif