decimal.go

Documentation: cuelang.org/go/internal/core/adt

     1  // Copyright 2020 CUE Authors
     2  //
     3  // Licensed under the Apache License, Version 2.0 (the "License");
     4  // you may not use this file except in compliance with the License.
     5  // You may obtain a copy of the License at
     6  //
     7  //     http://www.apache.org/licenses/LICENSE-2.0
     8  //
     9  // Unless required by applicable law or agreed to in writing, software
    10  // distributed under the License is distributed on an "AS IS" BASIS,
    11  // WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
    12  // See the License for the specific language governing permissions and
    13  // limitations under the License.
    14  
    15  package adt
    16  
    17  import (
    18  	"cuelang.org/go/internal"
    19  	"github.com/cockroachdb/apd/v3"
    20  )
    21  
    22  func (n *Num) Impl() *apd.Decimal {
    23  	return &n.X
    24  }
    25  
    26  func (n *Num) Negative() bool {
    27  	return n.X.Negative
    28  }
    29  
    30  func (a *Num) Cmp(b *Num) int {
    31  	return a.X.Cmp(&b.X)
    32  }
    33  
    34  func (c *OpContext) Add(a, b *Num) Value {
    35  	return numOp(c, internal.BaseContext.Add, a, b)
    36  }
    37  
    38  func (c *OpContext) Sub(a, b *Num) Value {
    39  	return numOp(c, internal.BaseContext.Sub, a, b)
    40  }
    41  
    42  func (c *OpContext) Mul(a, b *Num) Value {
    43  	return numOp(c, internal.BaseContext.Mul, a, b)
    44  }
    45  
    46  func (c *OpContext) Quo(a, b *Num) Value {
    47  	v := numOp(c, internal.BaseContext.Quo, a, b)
    48  	if n, ok := v.(*Num); ok {
    49  		n.K = FloatKind
    50  	}
    51  	return v
    52  }
    53  
    54  func (c *OpContext) Pow(a, b *Num) Value {
    55  	return numOp(c, internal.BaseContext.Pow, a, b)
    56  }
    57  
    58  type numFunc func(z, x, y *apd.Decimal) (apd.Condition, error)
    59  
    60  func numOp(c *OpContext, fn numFunc, x, y *Num) Value {
    61  	var d apd.Decimal
    62  
    63  	cond, err := fn(&d, &x.X, &y.X)
    64  
    65  	if err != nil {
    66  		return c.NewErrf("failed arithmetic: %v", err)
    67  	}
    68  
    69  	if cond.DivisionByZero() {
    70  		return c.NewErrf("division by zero")
    71  	}
    72  
    73  	k := x.Kind() & y.Kind()
    74  	if k == 0 {
    75  		k = FloatKind
    76  	}
    77  	return c.newNum(&d, k)
    78  }
    79  
    80  func (c *OpContext) IntDiv(a, b *Num) Value {
    81  	return intDivOp(c, (*apd.BigInt).Div, a, b)
    82  }
    83  
    84  func (c *OpContext) IntMod(a, b *Num) Value {
    85  	return intDivOp(c, (*apd.BigInt).Mod, a, b)
    86  }
    87  
    88  func (c *OpContext) IntQuo(a, b *Num) Value {
    89  	return intDivOp(c, (*apd.BigInt).Quo, a, b)
    90  }
    91  
    92  func (c *OpContext) IntRem(a, b *Num) Value {
    93  	return intDivOp(c, (*apd.BigInt).Rem, a, b)
    94  }
    95  
    96  type intFunc func(z, x, y *apd.BigInt) *apd.BigInt
    97  
    98  func intDivOp(c *OpContext, fn intFunc, a, b *Num) Value {
    99  	if b.X.IsZero() {
   100  		return c.NewErrf("division by zero")
   101  	}
   102  
   103  	var x, y apd.Decimal
   104  	_, _ = internal.BaseContext.RoundToIntegralValue(&x, &a.X)
   105  	if x.Negative {
   106  		x.Coeff.Neg(&x.Coeff)
   107  	}
   108  	_, _ = internal.BaseContext.RoundToIntegralValue(&y, &b.X)
   109  	if y.Negative {
   110  		y.Coeff.Neg(&y.Coeff)
   111  	}
   112  
   113  	var d apd.Decimal
   114  
   115  	fn(&d.Coeff, &x.Coeff, &y.Coeff)
   116  
   117  	if d.Coeff.Sign() < 0 {
   118  		d.Coeff.Neg(&d.Coeff)
   119  		d.Negative = true
   120  	}
   121  
   122  	return c.newNum(&d, IntKind)
   123  }
   124
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