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// Copyright 2011 Aaron Jacobs. All Rights Reserved.
// Author: aaronjjacobs@gmail.com (Aaron Jacobs)
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
// http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.
package oglematchers
import (
"errors"
"fmt"
"math"
"reflect"
)
// LessThan returns a matcher that matches integer, floating point, or strings
// values v such that v < x. Comparison is not defined between numeric and
// string types, but is defined between all integer and floating point types.
//
// x must itself be an integer, floating point, or string type; otherwise,
// LessThan will panic.
func LessThan(x interface{}) Matcher {
v := reflect.ValueOf(x)
kind := v.Kind()
switch {
case isInteger(v):
case isFloat(v):
case kind == reflect.String:
default:
panic(fmt.Sprintf("LessThan: unexpected kind %v", kind))
}
return &lessThanMatcher{v}
}
type lessThanMatcher struct {
limit reflect.Value
}
func (m *lessThanMatcher) Description() string {
// Special case: make it clear that strings are strings.
if m.limit.Kind() == reflect.String {
return fmt.Sprintf("less than \"%s\"", m.limit.String())
}
return fmt.Sprintf("less than %v", m.limit.Interface())
}
func compareIntegers(v1, v2 reflect.Value) (err error) {
err = errors.New("")
switch {
case isSignedInteger(v1) && isSignedInteger(v2):
if v1.Int() < v2.Int() {
err = nil
}
return
case isSignedInteger(v1) && isUnsignedInteger(v2):
if v1.Int() < 0 || uint64(v1.Int()) < v2.Uint() {
err = nil
}
return
case isUnsignedInteger(v1) && isSignedInteger(v2):
if v1.Uint() <= math.MaxInt64 && int64(v1.Uint()) < v2.Int() {
err = nil
}
return
case isUnsignedInteger(v1) && isUnsignedInteger(v2):
if v1.Uint() < v2.Uint() {
err = nil
}
return
}
panic(fmt.Sprintf("compareIntegers: %v %v", v1, v2))
}
func getFloat(v reflect.Value) float64 {
switch {
case isSignedInteger(v):
return float64(v.Int())
case isUnsignedInteger(v):
return float64(v.Uint())
case isFloat(v):
return v.Float()
}
panic(fmt.Sprintf("getFloat: %v", v))
}
func (m *lessThanMatcher) Matches(c interface{}) (err error) {
v1 := reflect.ValueOf(c)
v2 := m.limit
err = errors.New("")
// Handle strings as a special case.
if v1.Kind() == reflect.String && v2.Kind() == reflect.String {
if v1.String() < v2.String() {
err = nil
}
return
}
// If we get here, we require that we are dealing with integers or floats.
v1Legal := isInteger(v1) || isFloat(v1)
v2Legal := isInteger(v2) || isFloat(v2)
if !v1Legal || !v2Legal {
err = NewFatalError("which is not comparable")
return
}
// Handle the various comparison cases.
switch {
// Both integers
case isInteger(v1) && isInteger(v2):
return compareIntegers(v1, v2)
// At least one float32
case v1.Kind() == reflect.Float32 || v2.Kind() == reflect.Float32:
if float32(getFloat(v1)) < float32(getFloat(v2)) {
err = nil
}
return
// At least one float64
case v1.Kind() == reflect.Float64 || v2.Kind() == reflect.Float64:
if getFloat(v1) < getFloat(v2) {
err = nil
}
return
}
// We shouldn't get here.
panic(fmt.Sprintf("lessThanMatcher.Matches: Shouldn't get here: %v %v", v1, v2))
}
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