Move src/modules/main -> src/kernel

src/kernel/font.cpp

@@ -0,0 +1,88 @@
+#include "font.h"
+
+/* PSF2 header format
+ * Taken from the Linux KBD documentation
+ * http://www.win.tue.nl/~aeb/linux/kbd/font-formats-1.html
+ */
+
+const static uint8_t magic[] = {0x72, 0xb5, 0x4a, 0x86};
+const static uint32_t max_version = 0;
+
+const static uint8_t unicode_sep = 0xff;
+const static uint8_t unicode_start = 0xfe;
+
+/* bits used in flags */
+enum psf2_flags {
+	psf2_has_unicode = 0x00000001
+};
+
+struct psf2_header {
+	uint8_t magic[4];
+	uint32_t version;
+	uint32_t header_size;	// offset of bitmaps in file
+	uint32_t flags;
+	uint32_t length;		// number of glyphs
+	uint32_t charsize;		// number of bytes for each character
+	uint32_t height, width; // max dimensions of glyphs
+};
+
+font
+font::load(void const *data)
+{
+	psf2_header const *psf2 = static_cast<psf2_header const *>(data);
+	for (int i = 0; i < sizeof(magic); ++i) {
+		if (psf2->magic[i] != magic[i]) {
+			return font{};
+		}
+	}
+
+	uint8_t const *font_data = static_cast<uint8_t const *>(data) + psf2->header_size;
+	return font{
+			psf2->height,
+			psf2->width,
+			psf2->length,
+			font_data};
+}
+
+font::font() :
+	m_count(0),
+	m_data(nullptr)
+{}
+
+font::font(unsigned height, unsigned width, unsigned count, uint8_t const *data) :
+	m_size(width, height),
+	m_count(count),
+	m_data(data)
+{}
+
+font::font(const font &other) :
+	m_size(other.m_size),
+	m_count(other.m_count),
+	m_data(other.m_data)
+{}
+
+void
+font::draw_glyph(
+		screen &s,
+		uint32_t glyph,
+		screen::pixel_t fg,
+		screen::pixel_t bg,
+		unsigned x,
+		unsigned y) const
+{
+	unsigned bwidth = (m_size.x+7)/8;
+	uint8_t const *data = m_data + (glyph * glyph_bytes());
+
+	for (int dy = 0; dy < m_size.y; ++dy) {
+		for (int dx = 0; dx < bwidth; ++dx) {
+			uint8_t byte = data[dy * bwidth + dx];
+			for (int i = 0; i < 8; ++i) {
+				if (dx*8 + i >= m_size.x) continue;
+				const uint8_t mask = 1 << (7-i);
+				uint32_t c = (byte & mask) ? fg : bg;
+				s.draw_pixel(x + dx*8 + i, y + dy, c);
+			}
+		}
+	}
+}
+