Added scale to bc_compare argument (#14802)

In the original specification, the scale of bc_num was directly changed
and compared.

This becomes a problem when objects are supported, so we will modify it
to compare without changing bc_num.

Author: SakiTakamachi

ext/bcmath/bcmath.c

@@ -638,7 +638,7 @@ PHP_FUNCTION(bccomp)
 		goto cleanup;
 	}
 
-	RETVAL_LONG(bc_compare(first, second));
+	RETVAL_LONG(bc_compare(first, second, scale));
 
 	cleanup: {
 		bc_free_num(&first);

ext/bcmath/libbcmath/src/add.c

@@ -49,7 +49,7 @@ bc_num bc_add(bc_num n1, bc_num n2, size_t scale_min)
 	} else {
 		/* subtraction must be done. */
 		/* Compare magnitudes. */
-		switch (_bc_do_compare(n1, n2, false)) {
+		switch (_bc_do_compare(n1, n2, scale_min, false)) {
 			case BCMATH_RIGHT_GREATER:
 				/* n1 is less than n2, subtract n1 from n2. */
 				sum = _bc_do_sub(n2, n1);

ext/bcmath/libbcmath/src/bcmath.h

@@ -112,7 +112,7 @@ typedef enum {
 	BCMATH_RIGHT_GREATER = -1
 } bcmath_compare_result;
 
-bcmath_compare_result bc_compare(bc_num n1, bc_num n2);
+bcmath_compare_result bc_compare(bc_num n1, bc_num n2, size_t scale);
 
 bool bc_is_zero(bc_num num);
 

ext/bcmath/libbcmath/src/compare.c

@@ -39,7 +39,7 @@
    than N2 and +1 if N1 is greater than N2.  If USE_SIGN is false, just
    compare the magnitudes. */
 
-bcmath_compare_result _bc_do_compare(bc_num n1, bc_num n2, bool use_sign)
+bcmath_compare_result _bc_do_compare(bc_num n1, bc_num n2, size_t scale, bool use_sign)
 {
 	char *n1ptr, *n2ptr;
 
@@ -73,9 +73,12 @@ bcmath_compare_result _bc_do_compare(bc_num n1, bc_num n2, bool use_sign)
 		}
 	}
 
+	size_t n1_scale = MIN(n1->n_scale, scale);
+	size_t n2_scale = MIN(n2->n_scale, scale);
+
 	/* If we get here, they have the same number of integer digits.
 	   check the integer part and the equal length part of the fraction. */
-	size_t count = n1->n_len + MIN (n1->n_scale, n2->n_scale);
+	size_t count = n1->n_len + MIN (n1_scale, n2_scale);
 	n1ptr = n1->n_value;
 	n2ptr = n2->n_value;
 
@@ -104,9 +107,9 @@ bcmath_compare_result _bc_do_compare(bc_num n1, bc_num n2, bool use_sign)
 	}
 
 	/* They are equal up to the last part of the equal part of the fraction. */
-	if (n1->n_scale != n2->n_scale) {
-		if (n1->n_scale > n2->n_scale) {
-			for (count = n1->n_scale - n2->n_scale; count > 0; count--) {
+	if (n1_scale != n2_scale) {
+		if (n1_scale > n2_scale) {
+			for (count = n1_scale - n2_scale; count > 0; count--) {
 				if (*n1ptr++ != 0) {
 					/* Magnitude of n1 > n2. */
 					if (!use_sign || n1->n_sign == PLUS) {
@@ -117,7 +120,7 @@ bcmath_compare_result _bc_do_compare(bc_num n1, bc_num n2, bool use_sign)
 				}
 			}
 		} else {
-			for (count = n2->n_scale - n1->n_scale; count > 0; count--) {
+			for (count = n2_scale - n1_scale; count > 0; count--) {
 				if (*n2ptr++ != 0) {
 					/* Magnitude of n1 < n2. */
 					if (!use_sign || n1->n_sign == PLUS) {
@@ -136,7 +139,7 @@ bcmath_compare_result _bc_do_compare(bc_num n1, bc_num n2, bool use_sign)
 
 
 /* This is the "user callable" routine to compare numbers N1 and N2. */
-bcmath_compare_result bc_compare(bc_num n1, bc_num n2)
+bcmath_compare_result bc_compare(bc_num n1, bc_num n2, size_t scale)
 {
-	return _bc_do_compare(n1, n2, true);
+	return _bc_do_compare(n1, n2, scale, true);
 }

ext/bcmath/libbcmath/src/private.h

@@ -97,7 +97,7 @@ static inline uint64_t BC_BSWAP64(uint64_t u)
 
 
 /* routines */
-bcmath_compare_result _bc_do_compare (bc_num n1, bc_num n2, bool use_sign);
+bcmath_compare_result _bc_do_compare (bc_num n1, bc_num n2, size_t scale, bool use_sign);
 bc_num _bc_do_add (bc_num n1, bc_num n2);
 bc_num _bc_do_sub (bc_num n1, bc_num n2);
 void _bc_rm_leading_zeros (bc_num num);

ext/bcmath/libbcmath/src/raisemod.c

@@ -59,7 +59,7 @@ raise_mod_status bc_raisemod(bc_num base, bc_num expo, bc_num mod, bc_num *resul
 	}
 
 	/* Any integer number mod 1 (or -1) must be equal to 0 */
-	if (_bc_do_compare(mod, BCG(_one_), false) == BCMATH_EQUAL) {
+	if (_bc_do_compare(mod, BCG(_one_), mod->n_scale, false) == BCMATH_EQUAL) {
 		bc_free_num (result);
 		*result = bc_new_num(1, scale);
 		return OK;

ext/bcmath/libbcmath/src/sqrt.c

@@ -51,7 +51,7 @@ bool bc_sqrt(bc_num *num, size_t scale)
 		return true;
 	}
 
-	bcmath_compare_result num_cmp_one = bc_compare(local_num, BCG(_one_));
+	bcmath_compare_result num_cmp_one = bc_compare(local_num, BCG(_one_), local_num->n_scale);
 	/* Square root of 1 is 1 */
 	if (num_cmp_one == BCMATH_EQUAL) {
 		bc_free_num (num);

ext/bcmath/libbcmath/src/sub.c

@@ -49,7 +49,7 @@ bc_num bc_sub(bc_num n1, bc_num n2, size_t scale_min)
 	} else {
 		/* subtraction must be done. */
 		/* Compare magnitudes. */
-		switch (_bc_do_compare(n1, n2, false)) {
+		switch (_bc_do_compare(n1, n2, scale_min, false)) {
 			case BCMATH_RIGHT_GREATER:
 				/* n1 is less than n2, subtract n1 from n2. */
 				diff = _bc_do_sub(n2, n1);