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  • // Copyright 2015 The Go Authors. All rights reserved.
    // Use of this source code is governed by a BSD-style
    // license that can be found in the LICENSE file.
    
    package big
    
    import (
    
    	"bytes"
    	"encoding/gob"
    
    	"testing"
    )
    
    var floatVals = []string{
    	"0",
    	"1",
    	"0.1",
    	"2.71828",
    	"1234567890",
    	"3.14e1234",
    	"3.14e-1234",
    	"0.738957395793475734757349579759957975985497e100",
    	"0.73895739579347546656564656573475734957975995797598589749859834759476745986795497e100",
    	"inf",
    	"Inf",
    }
    
    
    func TestFloatGobEncoding(t *testing.T) {
    	var medium bytes.Buffer
    
    	enc := gob.NewEncoder(&medium)
    	dec := gob.NewDecoder(&medium)
    
    	for _, test := range floatVals {
    		for _, sign := range []string{"", "+", "-"} {
    			for _, prec := range []uint{0, 1, 2, 10, 53, 64, 100, 1000} {
    
    				for _, mode := range []RoundingMode{ToNearestEven, ToNearestAway, ToZero, AwayFromZero, ToNegativeInf, ToPositiveInf} {
    					medium.Reset() // empty buffer for each test case (in case of failures)
    					x := sign + test
    
    					var tx Float
    					_, _, err := tx.SetPrec(prec).SetMode(mode).Parse(x, 0)
    					if err != nil {
    						t.Errorf("parsing of %s (%dbits, %v) failed (invalid test case): %v", x, prec, mode, err)
    						continue
    					}
    
    					// If tx was set to prec == 0, tx.Parse(x, 0) assumes precision 64. Correct it.
    					if prec == 0 {
    						tx.SetPrec(0)
    					}
    
    					if err := enc.Encode(&tx); err != nil {
    						t.Errorf("encoding of %v (%dbits, %v) failed: %v", &tx, prec, mode, err)
    						continue
    					}
    
    					var rx Float
    					if err := dec.Decode(&rx); err != nil {
    						t.Errorf("decoding of %v (%dbits, %v) failed: %v", &tx, prec, mode, err)
    						continue
    					}
    
    					if rx.Cmp(&tx) != 0 {
    						t.Errorf("transmission of %s failed: got %s want %s", x, rx.String(), tx.String())
    						continue
    					}
    
    					if rx.Prec() != prec {
    						t.Errorf("transmission of %s's prec failed: got %d want %d", x, rx.Prec(), prec)
    					}
    
    					if rx.Mode() != mode {
    						t.Errorf("transmission of %s's mode failed: got %s want %s", x, rx.Mode(), mode)
    					}
    
    					if rx.Acc() != tx.Acc() {
    						t.Errorf("transmission of %s's accuracy failed: got %s want %s", x, rx.Acc(), tx.Acc())
    					}
    
    func TestFloatCorruptGob(t *testing.T) {
    	var buf bytes.Buffer
    	tx := NewFloat(4 / 3).SetPrec(1000).SetMode(ToPositiveInf)
    	if err := gob.NewEncoder(&buf).Encode(tx); err != nil {
    		t.Fatal(err)
    	}
    	b := buf.Bytes()
    
    	var rx Float
    	if err := gob.NewDecoder(bytes.NewReader(b)).Decode(&rx); err != nil {
    		t.Fatal(err)
    	}
    
    
    	if err := gob.NewDecoder(bytes.NewReader(b[:10])).Decode(&rx); err != io.ErrUnexpectedEOF {
    		t.Errorf("got %v want EOF", err)
    
    	b[1] = 0
    	if err := gob.NewDecoder(bytes.NewReader(b)).Decode(&rx); err == nil {
    
    		t.Fatal("got nil want version error")
    
    func TestFloatJSONEncoding(t *testing.T) {
    	for _, test := range floatVals {
    		for _, sign := range []string{"", "+", "-"} {
    			for _, prec := range []uint{0, 1, 2, 10, 53, 64, 100, 1000} {
    
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    				if prec > 53 && testing.Short() {
    					continue
    				}
    
    				x := sign + test
    				var tx Float
    				_, _, err := tx.SetPrec(prec).Parse(x, 0)
    				if err != nil {
    					t.Errorf("parsing of %s (prec = %d) failed (invalid test case): %v", x, prec, err)
    					continue
    				}
    				b, err := json.Marshal(&tx)
    				if err != nil {
    					t.Errorf("marshaling of %v (prec = %d) failed: %v", &tx, prec, err)
    					continue
    				}
    				var rx Float
    				rx.SetPrec(prec)
    				if err := json.Unmarshal(b, &rx); err != nil {
    					t.Errorf("unmarshaling of %v (prec = %d) failed: %v", &tx, prec, err)
    					continue
    				}
    				if rx.Cmp(&tx) != 0 {
    					t.Errorf("JSON encoding of %v (prec = %d) failed: got %v want %v", &tx, prec, &rx, &tx)
    				}
    			}
    		}
    	}
    }
    
    
    func TestFloatGobDecodeShortBuffer(t *testing.T) {
    	for _, tc := range [][]byte{
    		[]byte{0x1, 0x0, 0x0, 0x0},
    		[]byte{0x1, 0xfa, 0x0, 0x0, 0x0, 0x0},
    	} {
    		err := NewFloat(0).GobDecode(tc)
    		if err == nil {
    			t.Error("expected GobDecode to return error for malformed input")
    		}
    	}
    }
    
    
    func TestFloatGobDecodeInvalid(t *testing.T) {
    	for _, tc := range []struct {
    		buf []byte
    		msg string
    	}{
    		{
    			[]byte{0x1, 0x2a, 0x20, 0x20, 0x20, 0x20, 0x0, 0x20, 0x20, 0x20, 0x0, 0x20, 0x20, 0x20, 0x20, 0x0, 0x0, 0x0, 0x0, 0xc},
    			"Float.GobDecode: msb not set in last word",
    		},
    		{
    			[]byte{1, 2, 0, 0, 0, 0, 0, 0, 0, 0, 0},
    			"Float.GobDecode: nonzero finite number with empty mantissa",
    		},
    	} {
    		err := NewFloat(0).GobDecode(tc.buf)
    		if err == nil || !strings.HasPrefix(err.Error(), tc.msg) {
    			t.Errorf("expected GobDecode error prefix: %s, got: %v", tc.msg, err)
    		}
    	}
    }
    
    
    func TestFloatAppendText(t *testing.T) {
    	for _, test := range floatVals {
    		for _, sign := range []string{"", "+", "-"} {
    			for _, prec := range []uint{0, 1, 2, 10, 53, 64, 100, 1000} {
    				if prec > 53 && testing.Short() {
    					continue
    				}
    				x := sign + test
    				var tx Float
    				_, _, err := tx.SetPrec(prec).Parse(x, 0)
    				if err != nil {
    					t.Errorf("parsing of %s (prec = %d) failed (invalid test case): %v", x, prec, err)
    					continue
    				}
    				buf := make([]byte, 4, 32)
    				b, err := tx.AppendText(buf)
    				if err != nil {
    					t.Errorf("marshaling of %v (prec = %d) failed: %v", &tx, prec, err)
    					continue
    				}
    				var rx Float
    				rx.SetPrec(prec)
    				if err := rx.UnmarshalText(b[4:]); err != nil {
    					t.Errorf("unmarshaling of %v (prec = %d) failed: %v", &tx, prec, err)
    					continue
    				}
    				if rx.Cmp(&tx) != 0 {
    					t.Errorf("AppendText of %v (prec = %d) failed: got %v want %v", &tx, prec, &rx, &tx)
    				}
    			}
    		}
    	}
    }
    
    func TestFloatAppendTextNil(t *testing.T) {
    	var x *Float
    	buf := make([]byte, 4, 16)
    	data, _ := x.AppendText(buf)
    	if string(data[4:]) != "<nil>" {
    		t.Errorf("got %q, want <nil>", data[4:])
    	}
    }