lib/fonts: Refactor glyph-pattern helpers

Change the signatures of the pattern helpers to align them with other
font-glyph helpers: use the font_glyph_ prefix and pass the glyph
buffer first.

Calculating the position of the involved bit is somewhat obfuscated
in the original implementation. Move it into the new helper
__font_glyph_pos() and use the result as array index and bit position.

Note that these bit helpers use a bit pitch, while other code uses a
byte pitch. This is intentional and required here.

v2:
- fix typos in commit message

Signed-off-by: Thomas Zimmermann <tzimmermann@suse.de>
Signed-off-by: Helge Deller <deller@gmx.de>

diff --git a/lib/fonts/font_rotate.c b/lib/fonts/font_rotate.c
index d107a8d0a2b01ef86ad7170cf67dbd9a295474da..d79ec5eef7123a09b547372107934566bc6054b4 100644 (file)
--- a/lib/fonts/font_rotate.c
+++ b/lib/fonts/font_rotate.c
@@ -15,21 +15,33 @@
 
 #include "font.h"
 
-static inline int pattern_test_bit(u32 x, u32 y, u32 pitch, const char *pat)
+static unsigned int __font_glyph_pos(unsigned int x, unsigned int y, unsigned int bit_pitch,
+                                    unsigned int *bit)
 {
-       u32 tmp = (y * pitch) + x, index = tmp / 8,  bit = tmp % 8;
+       unsigned int off = y * bit_pitch + x;
+       unsigned int bit_shift = off % 8;
 
-       pat += index;
-       return (*pat) & (0x80 >> bit);
+       *bit = 0x80 >> bit_shift; /* MSB has position 0, LSB has position 7 */
+
+       return off / 8;
 }
 
-static inline void pattern_set_bit(u32 x, u32 y, u32 pitch, char *pat)
+static bool font_glyph_test_bit(const unsigned char *glyph, unsigned int x, unsigned int y,
+                               unsigned int bit_pitch)
 {
-       u32 tmp = (y * pitch) + x, index = tmp / 8, bit = tmp % 8;
+       unsigned int bit;
+       unsigned int i = __font_glyph_pos(x, y, bit_pitch, &bit);
+
+       return glyph[i] & bit;
+}
 
-       pat += index;
+static void font_glyph_set_bit(unsigned char *glyph, unsigned int x, unsigned int y,
+                              unsigned int bit_pitch)
+{
+       unsigned int bit;
+       unsigned int i = __font_glyph_pos(x, y, bit_pitch, &bit);
 
-       (*pat) |= 0x80 >> bit;
+       glyph[i] |= bit;
 }
 
 static inline void rotate_cw(const char *in, char *out, u32 width, u32 height)
@@ -42,9 +54,8 @@ static inline void rotate_cw(const char *in, char *out, u32 width, u32 height)
 
        for (i = 0; i < h; i++) {
                for (j = 0; j < w; j++) {
-                       if (pattern_test_bit(j, i, width, in))
-                               pattern_set_bit(height - 1 - i - shift, j,
-                                               height, out);
+                       if (font_glyph_test_bit(in, j, i, width))
+                               font_glyph_set_bit(out, height - 1 - i - shift, j, height);
                }
        }
 }
@@ -81,10 +92,9 @@ static inline void rotate_ud(const char *in, char *out, u32 width, u32 height)
 
        for (i = 0; i < height; i++) {
                for (j = 0; j < width - shift; j++) {
-                       if (pattern_test_bit(j, i, width, in))
-                               pattern_set_bit(width - (1 + j + shift),
-                                               height - (1 + i),
-                                               width, out);
+                       if (font_glyph_test_bit(in, j, i, width))
+                               font_glyph_set_bit(out, width - (1 + j + shift),
+                                                  height - (1 + i), width);
                }
        }
 }
@@ -119,9 +129,8 @@ static inline void rotate_ccw(const char *in, char *out, u32 width, u32 height)
 
        for (i = 0; i < h; i++) {
                for (j = 0; j < w; j++) {
-                       if (pattern_test_bit(j, i, width, in))
-                               pattern_set_bit(i, width - 1 - j - shift,
-                                               height, out);
+                       if (font_glyph_test_bit(in, j, i, width))
+                               font_glyph_set_bit(out, i, width - 1 - j - shift, height);
                }
        }
 }