ext/bcmath: Use an enum for comparison result (#14374)

Improve logic of callers of bc_compare

ext/bcmath/libbcmath/src/add.c

@@ -50,16 +50,16 @@ bc_num bc_add(bc_num n1, bc_num n2, size_t scale_min)
 		/* subtraction must be done. */
 		/* Compare magnitudes. */
 		switch (_bc_do_compare(n1, n2, false)) {
-			case -1:
+			case BCMATH_RIGHT_GREATER:
 				/* n1 is less than n2, subtract n1 from n2. */
 				sum = _bc_do_sub(n2, n1);
 				sum->n_sign = n2->n_sign;
 				break;
-			case 0:
+			case BCMATH_EQUAL:
 				/* They are equal! return zero with the correct scale! */
 				sum = bc_new_num (1, MAX(scale_min, MAX(n1->n_scale, n2->n_scale)));
 				break;
-			case 1:
+			case BCMATH_LEFT_GREATER:
 				/* n2 is less than n1, subtract n2 from n1. */
 				sum = _bc_do_sub(n1, n2);
 				sum->n_sign = n1->n_sign;

ext/bcmath/libbcmath/src/bcmath.h

@@ -106,7 +106,13 @@ void bc_int2num(bc_num *num, int val);
 
 long bc_num2long(bc_num num);
 
-int bc_compare(bc_num n1, bc_num n2);
+typedef enum {
+	BCMATH_EQUAL = 0,
+	BCMATH_LEFT_GREATER = 1,
+	BCMATH_RIGHT_GREATER = -1
+} bcmath_compare_result;
+
+bcmath_compare_result bc_compare(bc_num n1, bc_num n2);
 
 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. */
 
-int _bc_do_compare(bc_num n1, bc_num n2, bool use_sign)
+bcmath_compare_result _bc_do_compare(bc_num n1, bc_num n2, bool use_sign)
 {
 	char *n1ptr, *n2ptr;
 
@@ -47,10 +47,10 @@ int _bc_do_compare(bc_num n1, bc_num n2, bool use_sign)
 	if (use_sign && n1->n_sign != n2->n_sign) {
 		if (n1->n_sign == PLUS) {
 			/* Positive N1 > Negative N2 */
-			return (1);
+			return BCMATH_LEFT_GREATER;
 		} else {
 			/* Negative N1 < Positive N1 */
-			return (-1);
+			return BCMATH_RIGHT_GREATER;
 		}
 	}
 
@@ -59,16 +59,16 @@ int _bc_do_compare(bc_num n1, bc_num n2, bool use_sign)
 		if (n1->n_len > n2->n_len) {
 			/* Magnitude of n1 > n2. */
 			if (!use_sign || n1->n_sign == PLUS) {
-				return (1);
+				return BCMATH_LEFT_GREATER;
 			} else {
-				return (-1);
+				return BCMATH_RIGHT_GREATER;
 			}
 		} else {
 			/* Magnitude of n1 < n2. */
 			if (!use_sign || n1->n_sign == PLUS) {
-				return (-1);
+				return BCMATH_RIGHT_GREATER;
 			} else {
-				return (1);
+				return BCMATH_LEFT_GREATER;
 			}
 		}
 	}
@@ -89,16 +89,16 @@ int _bc_do_compare(bc_num n1, bc_num n2, bool use_sign)
 		if (*n1ptr > *n2ptr) {
 			/* Magnitude of n1 > n2. */
 			if (!use_sign || n1->n_sign == PLUS) {
-				return (1);
+				return BCMATH_LEFT_GREATER;
 			} else {
-				return (-1);
+				return BCMATH_RIGHT_GREATER;
 			}
 		} else {
 			/* Magnitude of n1 < n2. */
 			if (!use_sign || n1->n_sign == PLUS) {
-				return (-1);
+				return BCMATH_RIGHT_GREATER;
 			} else {
-				return (1);
+				return BCMATH_LEFT_GREATER;
 			}
 		}
 	}
@@ -110,9 +110,9 @@ int _bc_do_compare(bc_num n1, bc_num n2, bool use_sign)
 				if (*n1ptr++ != 0) {
 					/* Magnitude of n1 > n2. */
 					if (!use_sign || n1->n_sign == PLUS) {
-						return (1);
+						return BCMATH_LEFT_GREATER;
 					} else {
-						return (-1);
+						return BCMATH_RIGHT_GREATER;
 					}
 				}
 			}
@@ -121,9 +121,9 @@ int _bc_do_compare(bc_num n1, bc_num n2, bool use_sign)
 				if (*n2ptr++ != 0) {
 					/* Magnitude of n1 < n2. */
 					if (!use_sign || n1->n_sign == PLUS) {
-						return (-1);
+						return BCMATH_RIGHT_GREATER;
 					} else {
-						return (1);
+						return BCMATH_LEFT_GREATER;
 					}
 				}
 			}
@@ -131,12 +131,12 @@ int _bc_do_compare(bc_num n1, bc_num n2, bool use_sign)
 	}
 
 	/* They must be equal! */
-	return (0);
+	return BCMATH_EQUAL;
 }
 
 
 /* This is the "user callable" routine to compare numbers N1 and N2. */
-int bc_compare(bc_num n1, bc_num n2)
+bcmath_compare_result bc_compare(bc_num n1, bc_num n2)
 {
 	return _bc_do_compare(n1, n2, true);
 }

ext/bcmath/libbcmath/src/private.h

@@ -97,7 +97,7 @@ static inline uint64_t BC_BSWAP64(uint64_t u)
 
 
 /* routines */
-int _bc_do_compare (bc_num n1, bc_num n2, bool use_sign);
+bcmath_compare_result _bc_do_compare (bc_num n1, bc_num n2, 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

@@ -58,6 +58,13 @@ raise_mod_status bc_raisemod(bc_num base, bc_num expo, bc_num mod, bc_num *resul
 		return MOD_IS_ZERO;
 	}
 
+	/* Any integer number mod 1 (or -1) must be equal to 0 */
+	if (_bc_do_compare(mod, BCG(_one_), false) == BCMATH_EQUAL) {
+		bc_free_num (result);
+		*result = bc_new_num(1, scale);
+		return OK;
+	}
+
 	/* Set initial values. */
 	power = bc_copy_num(base);
 	exponent = bc_copy_num(expo);
@@ -66,10 +73,6 @@ raise_mod_status bc_raisemod(bc_num base, bc_num expo, bc_num mod, bc_num *resul
 	bc_init_num(&parity);
 
 	/* Do the calculation. */
-	if (!_bc_do_compare(modulus, BCG(_one_), false)) {
-		bc_free_num (&temp);
-		temp = bc_new_num (1, scale);
-	} else {
 	while (!bc_is_zero(exponent)) {
 		(void) bc_divmod(exponent, BCG(_two_), &exponent, &parity, 0);
 		if (!bc_is_zero(parity)) {
@@ -79,7 +82,6 @@ raise_mod_status bc_raisemod(bc_num base, bc_num expo, bc_num mod, bc_num *resul
 		bc_multiply_ex(power, power, &power, scale);
 		(void) bc_modulo(power, modulus, &power, scale);
 	}
-	}
 
 	/* Assign the value. */
 	bc_free_num (&power);

ext/bcmath/libbcmath/src/sqrt.c

@@ -38,30 +38,32 @@
 
 bool bc_sqrt(bc_num *num, size_t scale)
 {
+	const bc_num local_num = *num;
 	/* Initial checks. */
-	int cmp_res = bc_compare(*num, BCG(_zero_));
+	if (bc_is_neg(local_num)) {
-	if (cmp_res < 0) {
+		/* Cannot take the square root of a negative number */
-		return false; /* error */
+		return false;
-	} else {
+	}
-		if (cmp_res == 0) {
+	/* Square root of 0 is 0 */
+	if (bc_is_zero(local_num)) {
 		bc_free_num (num);
 		*num = bc_copy_num(BCG(_zero_));
 		return true;
 	}
-	}
+
-	cmp_res = bc_compare(*num, BCG(_one_));
+	bcmath_compare_result num_cmp_one = bc_compare(local_num, BCG(_one_));
-	if (cmp_res == 0) {
+	/* Square root of 1 is 1 */
+	if (num_cmp_one == BCMATH_EQUAL) {
 		bc_free_num (num);
 		*num = bc_copy_num(BCG(_one_));
 		return true;
 	}
 
 	/* Initialize the variables. */
-	size_t rscale;
 	size_t cscale;
 	bc_num guess, guess1, point5, diff;
+	size_t rscale = MAX(scale, local_num->n_scale);
 
-	rscale = MAX (scale, (*num)->n_scale);
 	bc_init_num(&guess1);
 	bc_init_num(&diff);
 	point5 = bc_new_num (1, 1);
@@ -69,16 +71,16 @@ bool bc_sqrt(bc_num *num, size_t scale)
 
 
 	/* Calculate the initial guess. */
-	if (cmp_res < 0) {
+	if (num_cmp_one == BCMATH_RIGHT_GREATER) {
 		/* The number is between 0 and 1.  Guess should start at 1. */
 		guess = bc_copy_num(BCG(_one_));
-		cscale = (*num)->n_scale;
+		cscale = local_num->n_scale;
 	} else {
 		/* The number is greater than 1.  Guess should start at 10^(exp/2). */
 		bc_init_num(&guess);
 		bc_int2num(&guess, 10);
 
-		bc_int2num(&guess1, (*num)->n_len);
+		bc_int2num(&guess1, local_num->n_len);
 		bc_multiply_ex(guess1, point5, &guess1, 0);
 		guess1->n_scale = 0;
 		bc_raise_bc_exponent(guess, guess1, &guess, 0);

ext/bcmath/libbcmath/src/sub.c

@@ -50,18 +50,18 @@ bc_num bc_sub(bc_num n1, bc_num n2, size_t scale_min)
 		/* subtraction must be done. */
 		/* Compare magnitudes. */
 		switch (_bc_do_compare(n1, n2, false)) {
-			case -1:
+			case BCMATH_RIGHT_GREATER:
 				/* n1 is less than n2, subtract n1 from n2. */
 				diff = _bc_do_sub(n2, n1);
 				diff->n_sign = (n2->n_sign == PLUS ? MINUS : PLUS);
 				break;
-			case 0: {
+			case BCMATH_EQUAL: {
 				/* They are equal! return zero! */
 				size_t res_scale = MAX (scale_min, MAX(n1->n_scale, n2->n_scale));
 				diff = bc_new_num (1, res_scale);
 				break;
 			}
-			case 1:
+			case BCMATH_LEFT_GREATER:
 				/* n2 is less than n1, subtract n2 from n1. */
 				diff = _bc_do_sub(n1, n2);
 				diff->n_sign = n1->n_sign;