Add work in progress editor frontend

1 files changed, 106 insertions, 0 deletions

diff --git a/colors.c b/colors.c
new file mode 100644
index 0000000..d1a0357
--- /dev/null
+++ b/colors.c
@@ -0,0 +1,106 @@
+#include <stdbool.h>
+#include <stdlib.h>
+#include <curses.h>
+
+#include "editor.h"
+#include "util.h"
+
+#ifdef NCURSES_VERSION
+# ifndef NCURSES_EXT_COLORS
+#  define NCURSES_EXT_COLORS 0
+# endif
+# if !NCURSES_EXT_COLORS
+#  define MAX_COLOR_PAIRS 256
+# endif
+#endif
+#ifndef MAX_COLOR_PAIRS
+# define MAX_COLOR_PAIRS COLOR_PAIRS
+#endif
+
+static bool has_default_colors;
+static short *color2palette, default_fg, default_bg;
+static short color_pairs_reserved, color_pairs_max, color_pair_current;
+
+static unsigned int color_hash(short fg, short bg)
+{
+	if (fg == -1)
+		fg = COLORS;
+	if (bg == -1)
+		bg = COLORS + 1;
+	return fg * (COLORS + 2) + bg;
+}
+
+short editor_color_get(short fg, short bg)
+{
+	if (fg >= COLORS)
+		fg = default_fg;
+	if (bg >= COLORS)
+		bg = default_bg;
+
+	if (!has_default_colors) {
+		if (fg == -1)
+			fg = default_fg;
+		if (bg == -1)
+			bg = default_bg;
+	}
+
+	if (!color2palette || (fg == -1 && bg == -1))
+		return 0;
+	unsigned int index = color_hash(fg, bg);
+	if (color2palette[index] == 0) {
+		short oldfg, oldbg;
+		for (;;) {
+			if (++color_pair_current >= color_pairs_max)
+				color_pair_current = color_pairs_reserved + 1;
+			pair_content(color_pair_current, &oldfg, &oldbg);
+			unsigned int old_index = color_hash(oldfg, oldbg);
+			if (color2palette[old_index] >= 0) {
+				if (init_pair(color_pair_current, fg, bg) == OK) {
+					color2palette[old_index] = 0;
+					color2palette[index] = color_pair_current;
+				}
+				break;
+			}
+		}
+	}
+
+	short color_pair = color2palette[index];
+	return color_pair >= 0 ? color_pair : -color_pair;
+}
+
+short editor_color_reserve(short fg, short bg)
+{
+	if (!color2palette)
+		editor_init();
+	if (!color2palette || fg >= COLORS || bg >= COLORS)
+		return 0;
+	if (!has_default_colors && fg == -1)
+		fg = default_fg;
+	if (!has_default_colors && bg == -1)
+		bg = default_bg;
+	if (fg == -1 && bg == -1)
+		return 0;
+	unsigned int index = color_hash(fg, bg);
+	if (color2palette[index] >= 0) {
+		if (init_pair(++color_pairs_reserved, fg, bg) == OK)
+			color2palette[index] = -color_pairs_reserved;
+	}
+	short color_pair = color2palette[index];
+	return color_pair >= 0 ? color_pair : -color_pair;
+}
+
+void editor_init(void)
+{
+	if (color2palette)
+		return;
+	pair_content(0, &default_fg, &default_bg);
+	if (default_fg == -1)
+		default_fg = COLOR_WHITE;
+	if (default_bg == -1)
+		default_bg = COLOR_BLACK;
+	has_default_colors = (use_default_colors() == OK);
+	color_pairs_max = MIN(COLOR_PAIRS, MAX_COLOR_PAIRS);
+	if (COLORS)
+		color2palette = calloc((COLORS + 2) * (COLORS + 2), sizeof(short));
+	editor_color_reserve(COLOR_WHITE, COLOR_BLACK);
+}