changed STIX_SMOOI_MIN to -STIX_SMOOI_MAX instead of (-STIX_SMOOI_MAX - 1)

fixed tally range check bugs in dic.c/sym.c/gc.c
simplificed some code resulting from STIX_SMOOI_MIN change.

stix/kernel/Stix.st

@@ -115,18 +115,15 @@
 {
 }
 
-#class(#halfword) LargeInteger(Number)
+#class(#liword) LargeInteger(Number)
-## #class(#word) LargeInteger(Number)
 {
 }
 
-#class(#halfword) LargePositiveInteger(LargeInteger)
+#class(#liword) LargePositiveInteger(LargeInteger)
-## #class(#word) LargePositiveInteger(LargeInteger)
 {
 }
 
-#class(#halfword) LargeNegativeInteger(LargeInteger)
+#class(#liword) LargeNegativeInteger(LargeInteger)
-## #class(#word) LargeNegativeInteger(LargeInteger)
 {
 }
 

stix/kernel/test-005.st

@@ -267,6 +267,7 @@ PROCESS TESTING
 		##((-2305843009213693952 * -1) - 1 + 2) dump.
 		((-2305843009213693952 * -2305843009213693952 * 2305843009213693952 * 2305843009213693952 * 2305843009213693952) - 1 + 2) dump.
 		
+
 (2r111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111111 * 128971234897128931) dump.
 
 "

stix/lib/bigint.c

@@ -304,7 +304,7 @@ static stix_oop_t normalize_bigint (stix_t* stix, stix_oop_t oop)
 	count = count_effective_digits (oop);
 
 #if defined(STIX_USE_FULL_WORD)
-	if (count == 1)
+	if (count == 1) /* 1 word */
 	{
 		stix_oow_t w;
 
@@ -315,13 +315,13 @@ static stix_oop_t normalize_bigint (stix_t* stix, stix_oop_t oop)
 		}
 		else
 		{
+			STIX_ASSERT (-STIX_SMOOI_MAX  == STIX_SMOOI_MIN);
 			STIX_ASSERT (STIX_OBJ_GET_CLASS(oop) == stix->_large_negative_integer);
-			/*if (w <= -STIX_SMOOI_MIN) */
+			if (w <= STIX_SMOOI_MAX) return STIX_SMOOI_TO_OOP(-(stix_ooi_t)w);
-			if (w <= ((stix_oow_t)STIX_SMOOI_MAX + 1)) return STIX_SMOOI_TO_OOP(-(stix_ooi_t)w);
 		}
 	}
 #else
-	if (count == 1)
+	if (count == 1) /* 1 half-word */
 	{
 		if (STIX_OBJ_GET_CLASS(oop) == stix->_large_positive_integer)
 		{
@@ -330,10 +330,10 @@ static stix_oop_t normalize_bigint (stix_t* stix, stix_oop_t oop)
 		else
 		{
 			STIX_ASSERT (STIX_OBJ_GET_CLASS(oop) == stix->_large_negative_integer);
-			return STIX_SMOOI_TO_OOP(-(stix_oow_t)((stix_oop_liword_t)oop)->slot[0]);
+			return STIX_SMOOI_TO_OOP(-(stix_ooi_t)((stix_oop_liword_t)oop)->slot[0]);
 		}
 	}
-	else if (count == 2)
+	else if (count == 2) /* 2 half-words */
 	{
 		stix_oow_t w;
 
@@ -344,9 +344,9 @@ static stix_oop_t normalize_bigint (stix_t* stix, stix_oop_t oop)
 		}
 		else
 		{
+			STIX_ASSERT (-STIX_SMOOI_MAX  == STIX_SMOOI_MIN);
 			STIX_ASSERT (STIX_OBJ_GET_CLASS(oop) == stix->_large_negative_integer);
-			/*if (w <= -STIX_SMOOI_MIN) */
+			if (w <= STIX_SMOOI_MAX) return STIX_SMOOI_TO_OOP(-(stix_ooi_t)w);
-			if (w <= ((stix_oow_t)STIX_SMOOI_MAX + 1)) return STIX_SMOOI_TO_OOP(-(stix_ooi_t)w);
 		}
 	}
 #endif
@@ -632,6 +632,40 @@ static STIX_INLINE void rshift_unsigned_array (stix_liw_t* x, stix_oow_t xs, sti
 		STIX_MEMSET (&x[xs - word_shifts], 0, word_shifts * STIX_SIZEOF(stix_liw_t));
 }
 
+static void divide_unsigned_array (
+	const stix_liw_t* x, stix_oow_t xs, 
+	const stix_liw_t* y, stix_oow_t ys, 
+	stix_liw_t* q, stix_liw_t* r)
+{
+	/* TODO: this function needs to be rewritten for performance improvement. */
+
+	/* Perform binary long division.
+	 * http://en.wikipedia.org/wiki/Division_algorithm
+	 * ---------------------------------------------------------------------
+	 * Q := 0                 initialize quotient and remainder to zero
+	 * R := 0                     
+	 * for i = n-1...0 do     where n is number of bits in N
+	 *   R := R << 1          left-shift R by 1 bit    
+	 *   R(0) := X(i)         set the least-significant bit of R equal to bit i of the numerator
+	 *   if R >= Y then
+	 *     R = R - Y               
+	 *     Q(i) := 1
+	 *   end
+	 * end 
+	 */
+
+	stix_liw_t* d;
+	stix_oow_t ds;
+
+/* TODO: */
+	while (!is_less_unsigned_array (d, ds, y, ys)) /* while (y <= d) */
+	{
+		
+	}
+
+	STIX_MEMCPY (r, d, ds);
+}
+
 static stix_oop_t add_unsigned_integers (stix_t* stix, stix_oop_t x, stix_oop_t y)
 {
 	stix_liw_t* a, * b;
@@ -981,6 +1015,7 @@ printf ("%0*lX ", (int)(STIX_SIZEOF(stix_liw_t) * 2), (unsigned long)((stix_oop_
 printf ("\n");
 }
 
+/*
 lshift_unsigned_array (((stix_oop_liword_t)z)->slot, STIX_OBJ_GET_SIZE(z), 16 * 5 + 4);
 { int i;
 printf ("LSHIFT10=>");
@@ -989,7 +1024,7 @@ for (i = STIX_OBJ_GET_SIZE(z); i > 0;)
 printf ("%0*lX ", (int)(STIX_SIZEOF(stix_liw_t) * 2), (unsigned long)((stix_oop_liword_t)z)->slot[--i]);
 }
 printf ("\n");
-}
+}*/
 
 
 	return normalize_bigint (stix, z);
@@ -1001,6 +1036,80 @@ oops_einval:
 
 stix_oop_t stix_divints (stix_t* stix, stix_oop_t x, stix_oop_t y, stix_oop_t* rem)
 {
+	stix_oop_t t;
+
+	if (STIX_OOP_IS_SMOOI(x) && STIX_OOP_IS_SMOOI(y))
+	{
+		stix_ooi_t xv, yv, q, r;
+
+		xv = STIX_OOP_TO_SMOOI(x);
+		yv = STIX_OOP_TO_SMOOI(y);
+
+		if (yv == 0)
+		{
+			stix->errnum = STIX_EDIVBY0;
+			return STIX_NULL;
+		}
+
+		q = xv / yv;
+		STIX_ASSERT (STIX_IN_SMOOI_RANGE(q));
+
+#if 1
+/* TODO : verify this... */
+		r = xv - yv * q;
+		STIX_ASSERT (STIX_IN_SMOOI_RANGE(r));
+
+		/* handle sign difference */
+		if (r && ((yv ^ r) < 0))
+		{
+			/* if the sign bit is different betwen yv and r,
+			 * the sign bit of (yv ^ r) must be set */
+			r += yv;
+			--q;
+
+			STIX_ASSERT (STIX_IN_SMOOI_RANGE(r));
+		}
+#else
+		r = xv % yv;
+		STIX_ASSERT (STIX_IN_SMOOI_RANGE(r));
+#endif
+
+		*rem = STIX_SMOOI_TO_OOP(r);
+		return STIX_SMOOI_TO_OOP((stix_ooi_t)q);
+	}
+	else if (STIX_OOP_IS_SMOOI(x))
+	{
+		if (STIX_OOP_TO_SMOOI(x) == 0)
+		{
+			t = clone_bigint (stix, y, STIX_OBJ_GET_SIZE(y));
+			if (!t) return STIX_NULL;
+
+			*rem = t;
+			return STIX_SMOOI_TO_OOP(0);
+		}
+	}
+	else if (STIX_OOP_IS_SMOOI(y))
+	{
+		stix_ooi_t yv;
+
+		if (yv == 0)
+		{
+			stix->errnum = STIX_EDIVBY0;
+			return STIX_NULL;
+		}
+		else if (yv == 1)
+		{
+			t = clone_bigint (stix, x, STIX_OBJ_GET_SIZE(x));
+			if (!t) return STIX_NULL;
+
+			*rem = STIX_SMOOI_TO_OOP(0);
+			return t;
+		}
+	}
+	else
+	{
+	}
+
 	return STIX_NULL;
 }
 
@@ -1229,7 +1338,8 @@ printf ("\n");
 		w = hwp[0];
 		if (neg) 
 		{
-			if (w <= STIX_SMOOI_MAX + 1) return STIX_SMOOI_TO_OOP(-(stix_ooi_t)w);
+			STIX_ASSERT (-STIX_SMOOI_MAX == STIX_SMOOI_MIN);
+			if (w <= STIX_SMOOI_MAX) return STIX_SMOOI_TO_OOP(-(stix_ooi_t)w);
 		}
 		else 
 		{
@@ -1243,7 +1353,8 @@ printf ("\n");
 		w = MAKE_WORD(hwp[0], hwp[1]);
 		if (neg) 
 		{
-			if (w <= STIX_SMOOI_MAX + 1) return STIX_SMOOI_TO_OOP(-(stix_ooi_t)w);
+			STIX_ASSERT (-STIX_SMOOI_MAX == STIX_SMOOI_MIN);
+			if (w <= STIX_SMOOI_MAX) return STIX_SMOOI_TO_OOP(-(stix_ooi_t)w);
 		}
 		else 
 		{

stix/lib/comp.c

@@ -421,7 +421,6 @@ static int string_to_smint (stix_t* stix, stix_oocs_t* str, int radixed, stix_oo
 	 * it assumes a certain pre-sanity check on the string
 	 * done by the lexical analyzer */
 
-/* TODO: handle floating point numbers, etc, handle radix */
 	int v, negsign, base;
 	const stix_ooch_t* ptr, * end;
 	stix_oow_t value, old_value;
@@ -477,26 +476,15 @@ static int string_to_smint (stix_t* stix, stix_oocs_t* str, int radixed, stix_oo
 		return -1;
 	}
 
-	if (negsign)
+	STIX_ASSERT (-STIX_SMOOI_MAX == STIX_SMOOI_MIN);
-	{
-		/*if (value > -STIX_SMOOI_MIN) */
-		if (value > ((stix_oow_t)STIX_SMOOI_MAX + 1)) 
-		{
-			stix->errnum = STIX_ERANGE;
-			return -1;
-		}
-		*num = value;
-		*num *= -1;
-	}
-	else
-	{
 	if (value > STIX_SMOOI_MAX) 
 	{
 		stix->errnum = STIX_ERANGE;
 		return -1;
 	}
+
 	*num = value;
-	}
+	if (negsign) *num *= -1;
 
 	return 0;
 }
@@ -1860,7 +1848,7 @@ static int add_literal (stix_t* stix, stix_oop_t lit, stix_size_t* index)
 
 static STIX_INLINE int add_character_literal (stix_t* stix, stix_ooch_t ch, stix_size_t* index)
 {
-	return add_literal (stix, STIX_OOP_FROM_CHAR(ch), index);
+	return add_literal (stix, STIX_CHAR_TO_OOP(ch), index);
 }
 
 static int add_string_literal (stix_t* stix, const stix_oocs_t* str, stix_size_t* index)
@@ -3181,8 +3169,9 @@ static int __read_byte_array_literal (stix_t* stix, stix_oop_t* xlit)
 			 * than the range error must not occur */
 			STIX_ASSERT (stix->errnum == STIX_ERANGE);
 
-printf ("NOT IMPLEMENTED LARGE_INTEGER or ERROR?\n");
+			/* if the token is out of the SMOOI range, it's too big or 
-			stix->errnum = STIX_ENOIMPL;
+			 * to small to be a byte */
+			set_syntax_error (stix, STIX_SYNERR_BYTERANGE, &stix->c->tok.loc, &stix->c->tok.name);
 			return -1;
 		}
 		else if (tmp < 0 || tmp > 255)
@@ -3233,28 +3222,13 @@ static int __read_array_literal (stix_t* stix, stix_oop_t* xlit)
 
 			case STIX_IOTOK_NUMLIT:
 			case STIX_IOTOK_RADNUMLIT:
-			{
+				lit = string_to_num (stix, &stix->c->tok.name, stix->c->tok.type == STIX_IOTOK_RADNUMLIT);
-				stix_ooi_t tmp;
+				if (!lit) return -1;
-
-				if (string_to_smint(stix, &stix->c->tok.name, stix->c->tok.type == STIX_IOTOK_RADNUMLIT, &tmp) <= -1)
-				{
-					/* the token reader reads a valid token. no other errors
-					 * than the range error must not occur */
-					STIX_ASSERT (stix->errnum == STIX_ERANGE);
-
-/* TODO: IMPLMENET LARGE INTEGER */
-printf ("LARGE NOT IMPLEMENTED IN COMPILE_ARRAY_LITERAL\n");
-					stix->errnum = STIX_ENOIMPL;
-					return -1;
-				}
-
-				lit = STIX_SMOOI_TO_OOP(tmp);
 				break;
-			}
 
 			case STIX_IOTOK_CHARLIT:
 				STIX_ASSERT (stix->c->tok.name.len == 1);
-				lit = STIX_OOP_FROM_CHAR(stix->c->tok.name.ptr[0]);
+				lit = STIX_CHAR_TO_OOP(stix->c->tok.name.ptr[0]);
 				break;
 
 			case STIX_IOTOK_STRLIT:
@@ -3540,28 +3514,8 @@ printf ("\tpush symbol literal %d\n", (int)index);
 			case STIX_IOTOK_NUMLIT:
 			case STIX_IOTOK_RADNUMLIT:
 			{
-				/* TODO: other types of numbers, negative numbers, etc */
+/* TODO: floating pointer number */
-#if 0
+				/* TODO: other types of numbers, etc */
-/* TODO: proper numbeic literal handling */
-				stix_ooi_t tmp;
-
-				if (string_to_smint(stix, &stix->c->tok.name, stix->c->tok.type == STIX_IOTOK_RADNUMLIT, &tmp) <= -1)
-				{
-					/* the token reader reads a valid token. no other errors
-					 * than the range error must not occur */
-					STIX_ASSERT (stix->errnum == STIX_ERANGE);
-
-printf ("NOT IMPLEMENTED LARGE_INTEGER or ERROR?\n");
-					stix->errnum = STIX_ENOIMPL;
-					return -1;
-				}
-				else
-				{
-printf ("\tpush int literal\n");
-					if (emit_push_smint_literal(stix, tmp) <= -1) return -1;
-				}
-#else
-
 				stix_oop_t tmp;
 				tmp = string_to_num (stix, &stix->c->tok.name, stix->c->tok.type == STIX_IOTOK_RADNUMLIT);
 				if (!tmp) return -1;
@@ -3576,7 +3530,6 @@ printf ("\tpush int literal\n");
 					if (add_literal(stix, tmp, &index) <= -1 ||
 					    emit_single_param_instruction(stix, BCODE_PUSH_LITERAL_0, index) <= -1) return -1;
 				}
-#endif
 
 				GET_TOKEN (stix);
 				break;
@@ -4947,7 +4900,7 @@ printf ("\n");
 
 			case STIX_IOTOK_CHARLIT:
 				STIX_ASSERT (stix->c->tok.name.len == 1);
-				lit = STIX_OOP_FROM_CHAR(stix->c->tok.name.ptr[0]);
+				lit = STIX_CHAR_TO_OOP(stix->c->tok.name.ptr[0]);
 				goto add_literal;
 
 			case STIX_IOTOK_STRLIT:
@@ -4963,27 +4916,8 @@ printf ("\n");
 			case STIX_IOTOK_NUMLIT:
 			case STIX_IOTOK_RADNUMLIT:
 			{
-#if 0
-				stix_ooi_t tmp;
-
-				if (string_to_smint(stix, &stix->c->tok.name, stix->c->tok.type == STIX_IOTOK_RADNUMLIT, &tmp) <= -1)
-				{
-					/* the token reader reads a valid token. no other errors
-					 * than the range error must not occur */
-					STIX_ASSERT (stix->errnum == STIX_ERANGE);
-
-printf ("NOT IMPLEMENTED LARGE_INTEGER or ERROR?\n");
-					stix->errnum = STIX_ENOIMPL;
-					return -1;
-				}
-				else
-				{
-					lit = STIX_SMOOI_TO_OOP(tmp);
-				}
-#else
 				lit = string_to_num (stix, &stix->c->tok.name, stix->c->tok.type == STIX_IOTOK_RADNUMLIT);
 				if (!lit) return -1;
-#endif
 				goto add_literal;
 			}
 

stix/lib/dic.c

@@ -63,7 +63,8 @@ static stix_oop_oop_t expand_bucket (stix_t* stix, stix_oop_oop_t oldbuc)
 
 static stix_oop_association_t find_or_upsert (stix_t* stix, stix_oop_set_t dic, stix_oop_char_t key, stix_oop_t value)
 {
-	stix_oow_t index, tally;
+	stix_ooi_t tally;
+	stix_oow_t index;
 	stix_oop_association_t ass;
 	stix_oow_t tmp_count = 0;
 
@@ -75,6 +76,7 @@ static stix_oop_association_t find_or_upsert (stix_t* stix, stix_oop_set_t dic,
 
 	index = stix_hashchars(key->slot, STIX_OBJ_GET_SIZE(key)) % STIX_OBJ_GET_SIZE(dic->bucket);
 
+	/* find */
 	while (dic->bucket->slot[index] != stix->_nil) 
 	{
 		ass = (stix_oop_association_t)dic->bucket->slot[index];
@@ -86,7 +88,7 @@ static stix_oop_association_t find_or_upsert (stix_t* stix, stix_oop_set_t dic,
 		    stix_equalchars (key->slot, ((stix_oop_char_t)ass->key)->slot, STIX_OBJ_GET_SIZE(key))) 
 		{
 			/* the value of STIX_NULL indicates no insertion or update. */
-			if (value) ass->value = value;
+			if (value) ass->value = value; /* update */
 			return ass;
 		}
 
@@ -101,11 +103,25 @@ static stix_oop_association_t find_or_upsert (stix_t* stix, stix_oop_set_t dic,
 		return STIX_NULL;
 	}
 
+	/* the key is not found. insert it. */
+	STIX_ASSERT (STIX_OOP_IS_SMOOI(dic->tally));
+	tally = STIX_OOP_TO_SMOOI(dic->tally);
+	if (tally >= STIX_SMOOI_MAX)
+	{
+		/* this built-in dictionary is not allowed to hold more than 
+		 * STIX_SMOOI_MAX items for efficiency sake */
+		stix->errnum = STIX_EDFULL;
+		return STIX_NULL;
+	}
+
 	stix_pushtmp (stix, (stix_oop_t*)&dic); tmp_count++;
 	stix_pushtmp (stix, (stix_oop_t*)&key); tmp_count++;
 	stix_pushtmp (stix, &value); tmp_count++;
 
-	tally = STIX_OOP_TO_SMOOI(dic->tally);
+	/* no conversion to stix_oow_t is necessary for tally + 1.
+	 * the maximum value of tally is checked to be STIX_SMOOI_MAX - 1.
+	 * tally + 1 can produce at most STIX_SMOOI_MAX. above all, 
+	 * STIX_SMOOI_MAX is way smaller than STIX_TYPE_MAX(stix_ooi_t). */
 	if (tally + 1 >= STIX_OBJ_GET_SIZE(dic->bucket))
 	{
 		stix_oop_oop_t bucket;
@@ -114,7 +130,7 @@ static stix_oop_association_t find_or_upsert (stix_t* stix, stix_oop_set_t dic,
 			     it just before it gets full. The polcy can be grow it
 			     if it's 70% full */
 
-		/* Enlarge the symbol table before it gets full to
+		/* enlarge the bucket before it gets full to
 		 * make sure that it has at least one free slot left
 		 * after having added a new symbol. this is to help
 		 * traversal end at a _nil slot if no entry is found. */
@@ -138,6 +154,8 @@ static stix_oop_association_t find_or_upsert (stix_t* stix, stix_oop_set_t dic,
 	ass->key = (stix_oop_t)key;
 	ass->value = value;
 
+	/* the current tally must be less than the maximum value. otherwise,
+	 * it overflows after increment below */
 	STIX_ASSERT (tally < STIX_SMOOI_MAX);
 	dic->tally = STIX_SMOOI_TO_OOP(tally + 1);
 	dic->bucket->slot[index] = (stix_oop_t)ass;

stix/lib/exec.c

@@ -688,7 +688,7 @@ static int prim_basic_at (stix_t* stix, stix_ooi_t nargs)
 			break;
 
 		case STIX_OBJ_TYPE_CHAR:
-			v = STIX_OOP_FROM_CHAR(((stix_oop_char_t)rcv)->slot[idx]);
+			v = STIX_CHAR_TO_OOP(((stix_oop_char_t)rcv)->slot[idx]);
 			break;
 
 		case STIX_OBJ_TYPE_HALFWORD:
@@ -1491,7 +1491,7 @@ printf ("CALL MODE 222 ERROR %d %d\n", dcGetError (dc), DC_ERROR_UNSUPPORTED_MOD
 			case 'c':
 			{
 				char r = dcCallChar (dc, f);
-				ACTIVE_STACK_SETTOP (stix, STIX_OOP_FROM_CHAR(r));
+				ACTIVE_STACK_SETTOP (stix, STIX_CHAR_TO_OOP(r));
 				break;
 			}
 

stix/lib/gc.c

@@ -29,18 +29,25 @@
 static void compact_symbol_table (stix_t* stix, stix_oop_t _nil)
 {
 	stix_oop_char_t symbol;
-	stix_oow_t tally, index, i, x, y, z;
+	stix_oow_t i, x, y, z;
-	stix_oow_t bucket_size;
+	stix_oow_t bucket_size, index;
+	stix_ooi_t tally;
 
 #if defined(STIX_SUPPORT_GC_DURING_IGNITION)
 	if (!stix->symtab) return; /* symbol table has not been created */
 #endif
 
-	bucket_size = STIX_OBJ_GET_SIZE(stix->symtab->bucket);
+	/* the symbol table doesn't allow more data items than STIX_SMOOI_MAX.
-
+	 * so stix->symtab->tally must always be a small integer */
+	STIX_ASSERT (STIX_OOP_IS_SMOOI(stix->symtab->tally));
 	tally = STIX_OOP_TO_SMOOI(stix->symtab->tally);
+	STIX_ASSERT (tally >= 0); /* it must not be less than 0 */
 	if (tally <= 0) return;
 
+	/* NOTE: in theory, the bucket size can be greater than STIX_SMOOI_MAX
+	 * as it is an internal header field and is of an unsigned type */
+	bucket_size = STIX_OBJ_GET_SIZE(stix->symtab->bucket);
+
 	for (index = 0; index < bucket_size; )
 	{
 		if (STIX_OBJ_GET_FLAGS_MOVED(stix->symtab->bucket->slot[index]))
@@ -79,6 +86,7 @@ static void compact_symbol_table (stix_t* stix, stix_oop_t _nil)
 		tally--;
 	}
 
+	STIX_ASSERT (tally >= 0);
 	STIX_ASSERT (tally <= STIX_SMOOI_MAX);
 	stix->symtab->tally = STIX_SMOOI_TO_OOP(tally);
 }

stix/lib/stix.h

@@ -49,6 +49,8 @@ enum stix_errnum_t
 	STIX_EINVAL,  /**< invalid parameter or data */
 	STIX_ERANGE,  /**< range error. overflow and underflow */
 	STIX_ENOENT,  /**< no matching entry */
+	STIX_EDFULL,  /**< dictionary full */
+	STIX_EDIVBY0, /**< divide by zero */
 	STIX_EIOERR,  /**< I/O error */
 	STIX_EECERR,  /**< encoding conversion error */
 
@@ -157,12 +159,15 @@ typedef struct stix_obj_word_t*     stix_oop_word_t;
 #define STIX_OOP_IS_CHAR(oop) (((stix_oow_t)oop) & STIX_OOP_TAG_CHAR)
 #define STIX_SMOOI_TO_OOP(num) ((stix_oop_t)((((stix_ooi_t)(num)) << STIX_OOP_TAG_BITS) | STIX_OOP_TAG_SMINT))
 #define STIX_OOP_TO_SMOOI(oop) (((stix_ooi_t)oop) >> STIX_OOP_TAG_BITS)
-#define STIX_OOP_FROM_CHAR(num) ((stix_oop_t)((((stix_oow_t)(num)) << STIX_OOP_TAG_BITS) | STIX_OOP_TAG_CHAR))
+#define STIX_CHAR_TO_OOP(num) ((stix_oop_t)((((stix_oow_t)(num)) << STIX_OOP_TAG_BITS) | STIX_OOP_TAG_CHAR))
 #define STIX_OOP_TO_CHAR(oop) (((stix_oow_t)oop) >> STIX_OOP_TAG_BITS)
 
 #define STIX_SMINT_BITS (STIX_SIZEOF(stix_ooi_t) * 8 - STIX_OOP_TAG_BITS)
 #define STIX_SMOOI_MAX ((stix_ooi_t)(~((stix_oow_t)0) >> (STIX_OOP_TAG_BITS + 1)))
-#define STIX_SMOOI_MIN (-STIX_SMOOI_MAX - 1)
+/* Sacrificing 1 bit pattern for a negative SMOOI makes implementation
+ * a lot eaisier in many parts */
+/*#define STIX_SMOOI_MIN (-STIX_SMOOI_MAX - 1)*/
+#define STIX_SMOOI_MIN (-STIX_SMOOI_MAX)
 #define STIX_IN_SMOOI_RANGE(ooi)  ((ooi) >= STIX_SMOOI_MIN && (ooi) <= STIX_SMOOI_MAX)
 
 /* TODO: There are untested code where smint is converted to stix_oow_t.

stix/lib/sym.c

@@ -60,7 +60,8 @@ static stix_oop_oop_t expand_bucket (stix_t* stix, stix_oop_oop_t oldbuc)
 
 static stix_oop_t find_or_make_symbol (stix_t* stix, const stix_ooch_t* ptr, stix_oow_t len, int create)
 {
-	stix_oow_t index, tally;
+	stix_ooi_t tally;
+	stix_oow_t index;
 	stix_oop_char_t symbol;
 
 	STIX_ASSERT (len > 0);
@@ -95,7 +96,21 @@ static stix_oop_t find_or_make_symbol (stix_t* stix, const stix_ooch_t* ptr, sti
 		return STIX_NULL;
 	}
 
+	/* make a new symbol and insert it */
+	STIX_ASSERT (STIX_OOP_IS_SMOOI(stix->symtab->tally));
 	tally = STIX_OOP_TO_SMOOI(stix->symtab->tally);
+	if (tally >= STIX_SMOOI_MAX)
+	{
+		/* this built-in table is not allowed to hold more than 
+		 * STIX_SMOOI_MAX items for efficiency sake */
+		stix->errnum = STIX_EDFULL;
+		return STIX_NULL;
+	}
+
+	/* no conversion to stix_oow_t is necessary for tally + 1.
+	 * the maximum value of tally is checked to be STIX_SMOOI_MAX - 1.
+	 * tally + 1 can produce at most STIX_SMOOI_MAX. above all, 
+	 * STIX_SMOOI_MAX is way smaller than STIX_TYPE_MAX(stix_ooi_t). */
 	if (tally + 1 >= STIX_OBJ_GET_SIZE(stix->symtab->bucket))
 	{
 		stix_oop_oop_t bucket;
@@ -104,7 +119,7 @@ static stix_oop_t find_or_make_symbol (stix_t* stix, const stix_ooch_t* ptr, sti
 			     it just before it gets full. The polcy can be grow it
 			     if it's 70% full */
 
-		/* Enlarge the symbol table before it gets full to
+		/* enlarge the symbol table before it gets full to
 		 * make sure that it has at least one free slot left
 		 * after having added a new symbol. this is to help
 		 * traversal end at a _nil slot if no entry is found. */