add markdown viewer (mdv)

1 files changed, 238 insertions, 0 deletions

diff --git a/core/mdv.c b/core/mdv.c
new file mode 100644
index 0000000..25b7b28
--- /dev/null
+++ b/core/mdv.c
@@ -0,0 +1,238 @@
+#include "../lib/io/io.h"
+#include "../lib/sys/sizes.h"
+#include "../lib/tctl/tctl.h"
+#include "../lib/aec/aec.h"
+
+#define MAX_WIDTH 80
+
+#define TOGGLE(mask, type, sgron, sgroff) \
+					if (mask & type) { \
+						mask ^= type; \
+						wstdf("%S", sgroff); \
+					} else { \
+						mask |= type; \
+						wstdf("%S", sgron); \
+					}
+
+u16 heading_numbers[6] = { 0 };
+window_size_t ws;
+
+enum Style {
+	ITALIC       = 1,
+	BOLD         = 2,
+	STRIKETROUGH = 4,
+	MARKED       = 8,
+};
+
+
+void next_heading(int type)
+{
+	heading_numbers[type]++;
+
+	for (int i = type + 1; i < 5; ++i)
+		heading_numbers[i] = 0;
+}
+
+
+void show_box()
+{
+	char c;
+	u8 width = 0;
+	read(STDIN_FD, &c, 1);
+	read(STDIN_FD, &c, 1);
+	read(STDIN_FD, &c, 1);
+	u8 use_backup = 0;
+	char backup[3];
+
+	wstd("┌");
+	for (int i = 0; i < MAX_WIDTH - 3; ++i) wstd("─");
+	wstd("┐\n│ ");
+
+	while (use_backup || read(STDIN_FD, &c, 1)) {
+		if (use_backup) {
+			c = backup[3 - use_backup];
+			use_backup--;
+		}
+
+		if (c == '\n') {
+			for (int i = width + 1; i < MAX_WIDTH - 4; ++i) wstd(" ");
+
+			width = 0;
+			read(STDIN_FD, backup, 3);
+
+			if (backup[0] == '`' && backup[1] == '`' && backup[2] == '`')
+				break;
+			
+			use_backup = 3;
+
+			wstd(" │\n│ ");
+		} else {
+			++width;
+
+			if (width == MAX_WIDTH - 4) {
+				wstd(" │\n│ ");
+				width = 1;
+			}
+
+			putchar(c);
+		}
+	}
+
+	wstd(" │\n└");
+	for (int i = 0; i < MAX_WIDTH - 3; ++i) wstd("─");
+	wstd("┘\n\n");
+}
+
+
+void show_and_replace_leading_char(char leading, char *replace)
+{
+	char c;
+	u8 last_was_newline = 0;
+	wstdf("  %s", replace);
+
+	while (read(STDIN_FD, &c, 1)) {
+		if (c == '\n') {
+			if (last_was_newline)
+				break;
+
+			last_was_newline = 1;
+			wstd("\n  ");
+		} else {
+			last_was_newline = 0;
+
+			if (c == leading)
+				wstd(replace);
+			else
+				putchar(c);
+		}
+	}
+
+	wstd("\n");
+}
+
+
+void show_numbered_list()
+{
+	char c;
+	u8 last_was_newline = 0;
+	read(STDIN_FD, &c, 1);
+
+	wstd("  1.");
+
+	while (read(STDIN_FD, &c, 1)) {
+		if (c == '\n') {
+			if (last_was_newline)
+				break;
+
+			last_was_newline = 1;
+			wstd("\n  ");
+		} else {
+			last_was_newline = 0;
+			putchar(c);
+		}
+	}
+
+	wstd("\n");
+}
+
+
+void show_paragraph()
+{
+	u8 last_was_newline = 0;
+	char c;
+	u8 width = 1;
+	u8 markup_mask = 0;
+
+	while (read(STDIN_FD, &c, 1)) {
+		if (c == '\n') {
+			if (last_was_newline)
+				break;
+
+			last_was_newline = 1;
+		} else {
+			last_was_newline = 0;
+			if (width == MAX_WIDTH) {
+				wstd("\n");
+				width = 0;
+			}
+
+			switch (c) {
+				case '*':
+					read(STDIN_FD, &c, 1);
+					if (c == '*') {
+						TOGGLE(markup_mask, BOLD, SGR_BOLD, SGR_INTENSITY_OFF);
+					} else {
+						TOGGLE(markup_mask, ITALIC, SGR_ITALIC, SGR_ITALIC_OFF);
+
+						if (c == '\n') {
+							last_was_newline = 1;
+						} else {
+							putchar(c);
+						}
+					}
+					break;
+				case '~': TOGGLE(markup_mask, STRIKETROUGH, SGR_CROSSED_OUT, SGR_CROSSED_OUT_OFF); break;
+				case '`': TOGGLE(markup_mask, MARKED, SGR_REVERSE, SGR_REVERSE_OFF); break;
+				default: putchar(c); break;
+			}
+
+			++width;
+		}
+	}
+
+	wstdf("\n\n%S", SGR_RESET);
+}
+
+
+void show_heading()
+{
+	u8 heading_type = 1;
+	char c;
+
+	while (read(STDIN_FD, &c, 1) && c == '#') heading_type++;
+
+	if (heading_type > 5)
+		heading_type = 5;
+
+	next_heading(heading_type - 1);
+
+	wstdf("%S%i", SGR_FAINT, heading_numbers[0]);
+
+	for (int i = 1; heading_numbers[i]; ++i)
+		wstdf(".%i", heading_numbers[i]);
+	
+	wstdf("%S  ", SGR_RESET);
+
+	wstdf("%S", SGR_BOLD);
+
+	if (c != ' ') putchar(c);
+
+	while (read(STDIN_FD, &c, 1) && c != '\n') putchar(c);
+	wstdf("\n\n%S", SGR_RESET);
+}
+
+int main(int argc, char **argv)
+{
+	if (argc != 1) {
+		wf(STDERR_FD, "mdv\n");
+		return -1;
+	}
+
+	ws = tctl_get_window_size();
+
+	char c;
+
+	while (read(STDIN_FD, &c, 1)) {
+		switch(c) {
+			case '\n': break;
+			case '#':  show_heading();                          break;
+			case '1':  show_numbered_list();                    break;
+			case '`':  show_box();                              break;
+			case '-':  show_and_replace_leading_char('-', "•"); break;
+			case '>':  show_and_replace_leading_char('>', "│"); break;
+			default: putchar(c); show_paragraph();
+		}
+	}
+
+	return 0;
+}