Beginnings of support for Unicode variation selectors

These are treated as particularly odd Unicode code points and packed
into the "unicode" field.  Currently only the encoding side is
implemented, withe the slashed zero, <U+0030, U+FE00>, as a motivating
example.

Generating a format 14 'cmap' subtable and properly formatting the
glyph complement are still to come.

diff --git a/bedstead.c b/bedstead.c
index b856ecf753fe2dfd4b1cf70f689916cb9b092a1d..32623ca209d7a6df078127d53daf236e37dc3447 100644 (file)
--- a/bedstead.c
+++ b/bedstead.c
@@ -226,8 +226,15 @@ static struct glyph {
                char const *alias_of;
                int subr_idx;
        };
-       uint_least32_t unicode;
-#define NU (0xFFFFFFFF)
+       uint_least32_t unicode; /* Code point and maybe variation selector. */
+#define U_UVMASK 0x001FFFFF /* Code point of base character. */
+#define U_HASVS  0x00200000 /* Is there a variation selector? */
+#define U_VSMASK 0x0F000000 /* Bottom 4 bits of VS code point. */
+#define U_VSSHIFT 24
+#define VS(uvs) ((((long)uvs << U_VSSHIFT) & U_VSMASK) | U_HASVS)
+#define GET_UV(u) (u & U_UVMASK)
+#define GET_UVS(u) ((u & U_VSMASK) >> U_VSSHIFT)
+#define NU 0xFFFFFFFF /* No Unicode code point. Must be > all valid values. */
        char const *name;
        uint_least16_t flags;
 #define SEP  0x01 /* Separated graphics */
@@ -544,7 +551,8 @@ static struct glyph {
  /* Basic Latin */
  ALIAS("quotesingle.curly", "quoteright"),
  {"\00\00\04\12\21\12\04\00\00", NU, "zero.onum" },
- {"\16\21\23\25\31\21\16\00\00", NU, "zero.zero" },
+ ALIAS("zero.zero", "zero_uniFE00"), /* slashed zero */
+ {"\16\21\23\25\31\21\16\00\00", 0x0030 + VS(0xfe00), "zero_uniFE00" },
  {"\00\00\04\14\04\04\16\00\00", NU, "one.onum" },
  {"\00\00\36\01\16\20\37\00\00", NU, "two.onum" },
  {"\00\00\37\01\02\06\01\21\16", NU, "three.onum" },