[hackers] [libgrapheme] Optimize the bit extraction a bit || Laslo Hunhold

[git]

commit 52a25d52f16697e74dfd582217de5d169c3790cb
Author:     Laslo Hunhold <d...@frign.de>
AuthorDate: Thu May 28 19:32:01 2020 +0200
Commit:     Laslo Hunhold <d...@frign.de>
CommitDate: Thu May 28 19:32:01 2020 +0200

    Optimize the bit extraction a bit
    
    Thanks Mattias for the suggestion!
    
    Signed-off-by: Laslo Hunhold <d...@frign.de>

diff --git a/src/codepoint.c b/src/codepoint.c
index 8e69151..e20fdf5 100644
--- a/src/codepoint.c
+++ b/src/codepoint.c
@@ -58,9 +58,9 @@ grapheme_cp_decode(uint32_t *cp, const uint8_t *s, size_t n)
                        /*
                         * first byte is within the bounds; fill
                         * p with the the first bits contained in
-                        * the first byte ("upper-lower" is the bitmask)
+                        * the first byte (by subtracting the high bits)
                         */
-                       *cp = s[0] & (lut[off].upper - lut[off].lower);
+                       *cp = s[0] - lut[off].lower;
                        break;
                }
        }