ext/bcmath: If the result is 0, n_scale is set to 0. (php#18056)

Author: SakiTakamachi

NEWS

@@ -4,6 +4,7 @@ PHP                                                                        NEWS
 
 - BCMath:
   . Simplify `bc_divide()` code. (SakiTakamachi)
+  . If the result is 0, n_scale is set to 0. (SakiTakamachi)
 
 - CLI:
   . Add --ini=diff to print INI settings changed from the builtin default.

ext/bcmath/bcmath.c

@@ -807,8 +807,8 @@ PHP_FUNCTION(bcround)
 		goto cleanup;
 	}
 
-	bc_round(num, precision, mode, &result);
-	RETVAL_NEW_STR(bc_num2str_ex(result, result->n_scale));
+	size_t scale = bc_round(num, precision, mode, &result);
+	RETVAL_NEW_STR(bc_num2str_ex(result, scale));
 
 	cleanup: {
 		bc_free_num(&num);
@@ -1799,9 +1799,10 @@ PHP_METHOD(BcMath_Number, round)
 	bcmath_number_obj_t *intern = get_bcmath_number_from_zval(ZEND_THIS);
 
 	bc_num ret = NULL;
-	bc_round(intern->num, precision, rounding_mode, &ret);
+	size_t scale = bc_round(intern->num, precision, rounding_mode, &ret);
+	bc_rm_trailing_zeros(ret);
 
-	bcmath_number_obj_t *new_intern = bcmath_number_new_obj(ret, ret->n_scale);
+	bcmath_number_obj_t *new_intern = bcmath_number_new_obj(ret, scale);
 	RETURN_OBJ(&new_intern->std);
 }
 

ext/bcmath/libbcmath/src/bcmath.h

@@ -157,7 +157,7 @@ bool bc_divmod(bc_num num1, bc_num num2, bc_num *quo, bc_num *rem, size_t scale)
 
 bc_num bc_floor_or_ceil(bc_num num, bool is_floor);
 
-void bc_round(bc_num num, zend_long places, zend_long mode, bc_num *result);
+size_t bc_round(bc_num num, zend_long places, zend_long mode, bc_num *result);
 
 typedef enum {
 	OK,

ext/bcmath/libbcmath/src/div.c

@@ -430,6 +430,7 @@ bool bc_divide(bc_num numerator, bc_num divisor, bc_num *quot, size_t scale)
 	_bc_rm_leading_zeros(*quot);
 	if (bc_is_zero(*quot)) {
 		(*quot)->n_sign = PLUS;
+		(*quot)->n_scale = 0;
 	} else {
 		(*quot)->n_sign = numerator->n_sign == divisor->n_sign ? PLUS : MINUS;
 	}

ext/bcmath/libbcmath/src/divmod.c

@@ -74,6 +74,7 @@ bool bc_divmod(bc_num num1, bc_num num2, bc_num *quot, bc_num *rem, size_t scale
 	(*rem)->n_scale = MIN(scale, (*rem)->n_scale);
 	if (bc_is_zero(*rem)) {
 		(*rem)->n_sign = PLUS;
+		(*rem)->n_scale = 0;
 	}
 
 	return true;

ext/bcmath/libbcmath/src/recmul.c

@@ -264,6 +264,7 @@ bc_num bc_multiply(bc_num n1, bc_num n2, size_t scale)
 	_bc_rm_leading_zeros(prod);
 	if (bc_is_zero(prod)) {
 		prod->n_sign = PLUS;
+		prod->n_scale = 0;
 	}
 	return prod;
 }

ext/bcmath/libbcmath/src/round.c

@@ -18,7 +18,8 @@
 #include "private.h"
 #include <stddef.h>
 
-void bc_round(bc_num num, zend_long precision, zend_long mode, bc_num *result)
+/* Returns the scale of the value after rounding. */
+size_t bc_round(bc_num num, zend_long precision, zend_long mode, bc_num *result)
 {
 	/* clear result */
 	bc_free_num(result);
@@ -43,19 +44,19 @@ void bc_round(bc_num num, zend_long precision, zend_long mode, bc_num *result)
 			case PHP_ROUND_HALF_ODD:
 			case PHP_ROUND_TOWARD_ZERO:
 				*result = bc_copy_num(BCG(_zero_));
-				return;
+				return 0;
 
 			case PHP_ROUND_CEILING:
 				if (num->n_sign == MINUS) {
 					*result = bc_copy_num(BCG(_zero_));
-					return;
+					return 0;
 				}
 				break;
 
 			case PHP_ROUND_FLOOR:
 				if (num->n_sign == PLUS) {
 					*result = bc_copy_num(BCG(_zero_));
-					return;
+					return 0;
 				}
 				break;
 
@@ -67,7 +68,7 @@ void bc_round(bc_num num, zend_long precision, zend_long mode, bc_num *result)
 
 		if (bc_is_zero(num)) {
 			*result = bc_copy_num(BCG(_zero_));
-			return;
+			return 0;
 		}
 
 		/* If precision is -3, it becomes 1000. */
@@ -78,7 +79,7 @@ void bc_round(bc_num num, zend_long precision, zend_long mode, bc_num *result)
 		}
 		(*result)->n_value[0] = 1;
 		(*result)->n_sign = num->n_sign;
-		return;
+		return 0;
 	}
 
 	/* Just like bcadd('1', '1', 4) becomes '2.0000', it pads with zeros at the end if necessary. */
@@ -90,7 +91,7 @@ void bc_round(bc_num num, zend_long precision, zend_long mode, bc_num *result)
 			(*result)->n_sign = num->n_sign;
 			memcpy((*result)->n_value, num->n_value, num->n_len + num->n_scale);
 		}
-		return;
+		return precision;
 	}
 
 	/*
@@ -222,7 +223,12 @@ void bc_round(bc_num num, zend_long precision, zend_long mode, bc_num *result)
 	}
 
 check_zero:
-	if (bc_is_zero(*result)) {
-		(*result)->n_sign = PLUS;
+	{
+		size_t scale = (*result)->n_scale;
+		if (bc_is_zero(*result)) {
+			(*result)->n_sign = PLUS;
+			(*result)->n_scale = 0;
+		}
+		return scale;
 	}
 }