Use hb_parse_double in CFF::dict_opset_t::parse_bcd

src/Makefile.sources

@@ -243,6 +243,8 @@ HB_ICU_headers = hb-icu.h
 
 # Sources for libharfbuzz-subset
 HB_SUBSET_sources = \
+	hb-number.cc \
+	hb-number.hh \
 	hb-ot-cff1-table.cc \
 	hb-ot-cff2-table.cc \
 	hb-static.cc \

src/hb-cff-interp-dict-common.hh

@@ -94,130 +94,52 @@ struct dict_opset_t : opset_t<number_t>
     }
   }
 
+  /* Turns CFF's BCD format into strtod understandable string */
   static double parse_bcd (byte_str_ref_t& str_ref)
   {
-    bool    neg = false;
-    double  int_part = 0;
-    uint64_t frac_part = 0;
-    uint32_t  frac_count = 0;
-    bool    exp_neg = false;
-    uint32_t  exp_part = 0;
-    bool    exp_overflow = false;
-    enum Part { INT_PART=0, FRAC_PART, EXP_PART } part = INT_PART;
+    if (unlikely (str_ref.in_error ())) return .0;
+
     enum Nibble { DECIMAL=10, EXP_POS, EXP_NEG, RESERVED, NEG, END };
-    const uint64_t MAX_FRACT = 0xFFFFFFFFFFFFFull; /* 1^52-1 */
-    const uint32_t MAX_EXP = 0x7FFu; /* 1^11-1 */
 
-    double  value = 0.0;
+    char buf[32];
     unsigned char byte = 0;
-    for (uint32_t i = 0;; i++)
+    for (unsigned i = 0, count = 0; count < ARRAY_LENGTH (buf); ++i, ++count)
     {
-      char d;
-      if ((i & 1) == 0)
+      unsigned nibble;
+      if (!(i & 1))
       {
-	if (!str_ref.avail ())
-	{
-	  str_ref.set_error ();
-	  return 0.0;
-	}
+	if (unlikely (!str_ref.avail ())) break;
+
 	byte = str_ref[0];
 	str_ref.inc ();
-	d = byte >> 4;
+	nibble = byte >> 4;
       }
       else
-	d = byte & 0x0F;
+	nibble = byte & 0x0F;
 
-      switch (d)
+      if (unlikely (nibble == RESERVED)) break;
+      else if (nibble == END)
       {
-	case RESERVED:
-	  str_ref.set_error ();
-	  return value;
-
-	case END:
-	  value = (double) (neg ? -int_part : int_part);
-	  if (frac_count > 0)
-	  {
-	    double frac = frac_part / pow (10.0, (double) frac_count);
-	    if (neg) frac = -frac;
-	    value += frac;
-	  }
-	  if (unlikely (exp_overflow))
-	  {
-	    if (value == 0.0)
-	      return value;
-	    if (exp_neg)
-	      return neg ? -DBL_MIN : DBL_MIN;
-	    else
-	      return neg ? -DBL_MAX : DBL_MAX;
-	  }
-	  if (exp_part != 0)
-	  {
-	    if (exp_neg)
-	      value /= pow (10.0, (double) exp_part);
-	    else
-	      value *= pow (10.0, (double) exp_part);
-	  }
-	  return value;
-
-	case NEG:
-	  if (i != 0)
-	  {
-	    str_ref.set_error ();
-	    return 0.0;
-	  }
-	  neg = true;
-	  break;
-
-	case DECIMAL:
-	  if (part != INT_PART)
-	  {
-	    str_ref.set_error ();
-	    return value;
-	  }
-	  part = FRAC_PART;
+	const char *p = buf;
+	double pv;
+	if (unlikely (!hb_parse_double (&p, p + count, &pv, true/* whole buffer */)))
 	  break;
-
-	case EXP_NEG:
-	  exp_neg = true;
-	  HB_FALLTHROUGH;
-
-	case EXP_POS:
-	  if (part == EXP_PART)
-	  {
-	    str_ref.set_error ();
-	    return value;
-	  }
-	  part = EXP_PART;
-	  break;
-
-	default:
-	  switch (part) {
-	    default:
-	    case INT_PART:
-	      int_part = (int_part * 10) + d;
-	      break;
-
-	    case FRAC_PART:
-	      if (likely (frac_part <= MAX_FRACT / 10))
-	      {
-		frac_part = (frac_part * 10) + (unsigned)d;
-		frac_count++;
-	      }
-	      break;
-
-	    case EXP_PART:
-	      if (likely (exp_part * 10 + d <= MAX_EXP))
-	      {
-	      	exp_part = (exp_part * 10) + d;
-	      }
-	      else
-	      	exp_overflow = true;
-	      break;
-	  }
+	return pv;
+      }
+      else
+      {
+	buf[count] = "0123456789.EE?-?"[nibble];
+	if (nibble == EXP_NEG)
+	{
+	  ++count;
+	  if (unlikely (count == ARRAY_LENGTH (buf))) break;
+	  buf[count] = '-';
+	}
       }
     }
 
-    return value;
+    str_ref.set_error ();
+    return .0;
   }
 
   static bool is_hint_op (op_code_t op)