Boost C++ Libraries

...one of the most highly regarded and expertly designed C++ library projects in the world. Herb Sutter and Andrei Alexandrescu, C++ Coding Standards

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Performance

Tests description
clang-linux-2.8
gcc-4.4
gcc-4.5
gcc-4.6

In most cases boost::lexical_cast is faster than scanf, printf, std::stringstream. For more detailed info you can look at the tables below.

All the tests measure execution speed in milliseconds for 10000 iterations of the following code blocks:

Table 15.1. Tests source code

Test name

Code

lexical_cast

_out = boost::lexical_cast<OUTTYPE>(_in);

std::stringstream with construction

std::stringstream ss;
ss << _in;
if (ss.fail()) throw std::logic_error(descr);
ss >> _out;
if (ss.fail()) throw std::logic_error(descr);

std::stringstream without construction

ss << _in; // ss is an instance of std::stringstream
if (ss.fail()) throw std::logic_error(descr);
ss >> _out;
if (ss.fail()) throw std::logic_error(descr);
/* reseting std::stringstream to use it again */
ss.str(std::string());
ss.clear();

scanf/printf

typename OUTTYPE::value_type buffer[500];
sprintf( (char*)buffer, conv, _in);
_out = buffer;


Fastest results are highlitened with "!!! x !!!". Do not use this results to compare compilers, because tests were taken on different hardware.

Table 15.2. Performance Table (clang-linux-2.8)

From->To

lexical_cast

std::stringstream with construction

std::stringstream without construction

scanf/printf

string->char

!!! <1 !!!

148

14

12

string->signed char

!!! <1 !!!

97

8

7

string->unsigned char

!!! <1 !!!

90

8

13

string->int

!!! 4 !!!

102

19

15

string->short

!!! 4 !!!

105

20

15

string->long int

!!! 4 !!!

105

19

15

string->long long

!!! 4 !!!

115

19

14

string->unsigned int

!!! 4 !!!

102

18

14

string->unsigned short

!!! 4 !!!

101

19

15

string->unsigned long int

!!! 3 !!!

107

20

14

string->unsigned long long

!!! 3 !!!

103

20

14

string->bool

!!! <1 !!!

97

16

8

string->float

!!! 21 !!!

170

61

32

string->double

!!! 18 !!!

206

93

58

string->long double

135

221

94

!!! 57 !!!

char->string

!!! 7 !!!

100

17

13

unsigned char->string

!!! 7 !!!

99

18

16

signed char->string

!!! 7 !!!

101

17

12

int->string

!!! 13 !!!

110

23

15

short->string

!!! 13 !!!

112

24

18

long int->string

!!! 13 !!!

119

23

17

long long->string

!!! 13 !!!

110

23

18

unsigned int->string

!!! 14 !!!

113

24

17

unsigned short->string

!!! 13 !!!

108

24

17

unsigned long int->string

!!! 13 !!!

109

24

16

unsigned long long->string

!!! 13 !!!

110

23

17

bool->string

!!! 7 !!!

105

24

12

float->string

70

192

94

!!! 49 !!!

double->string

106

217

122

!!! 76 !!!

long double->string

120

219

123

!!! 80 !!!

char*->char

!!! 2 !!!

90

9

8

char*->signed char

!!! 2 !!!

87

10

7

char*->unsigned char

!!! 3 !!!

90

10

13

char*->int

!!! 6 !!!

107

21

15

char*->short

!!! 6 !!!

110

19

14

char*->long int

!!! 6 !!!

103

19

14

char*->long long

!!! 7 !!!

104

20

15

char*->unsigned int

!!! 6 !!!

101

20

15

char*->unsigned short

!!! 7 !!!

100

20

14

char*->unsigned long int

!!! 6 !!!

105

22

15

char*->unsigned long long

!!! 7 !!!

106

21

14

char*->bool

!!! 2 !!!

99

18

7

char*->float

!!! 22 !!!

159

67

33

char*->double

!!! 20 !!!

205

94

58

char*->long double

140

214

95

!!! 58 !!!

unsigned char*->char

!!! 2 !!!

92

9

7

unsigned char*->signed char

!!! 2 !!!

89

10

7

unsigned char*->unsigned char

!!! 2 !!!

89

10

14

unsigned char*->int

!!! 6 !!!

104

20

14

unsigned char*->short

!!! 6 !!!

106

21

14

unsigned char*->long int

!!! 6 !!!

105

19

14

unsigned char*->long long

!!! 6 !!!

106

20

15

unsigned char*->unsigned int

!!! 7 !!!

105

19

14

unsigned char*->unsigned short

!!! 6 !!!

103

19

14

unsigned char*->unsigned long int

!!! 6 !!!

106

19

14

unsigned char*->unsigned long long

!!! 6 !!!

104

21

15

unsigned char*->bool

!!! 2 !!!

102

18

7

unsigned char*->float

!!! 23 !!!

160

66

32

unsigned char*->double

!!! 20 !!!

201

95

58

unsigned char*->long double

144

221

95

!!! 60 !!!

unsigned char*->string

!!! 12 !!!

104

23

---

signed char*->char

!!! 2 !!!

90

9

7

signed char*->signed char

!!! 2 !!!

89

9

7

signed char*->unsigned char

!!! 2 !!!

89

10

13

signed char*->int

!!! 6 !!!

106

19

15

signed char*->short

!!! 6 !!!

107

20

15

signed char*->long int

!!! 6 !!!

103

19

14

signed char*->long long

!!! 6 !!!

103

19

14

signed char*->unsigned int

!!! 6 !!!

101

19

15

signed char*->unsigned short

!!! 6 !!!

101

19

16

signed char*->unsigned long int

!!! 6 !!!

105

22

15

signed char*->unsigned long long

!!! 6 !!!

104

21

15

signed char*->bool

!!! 2 !!!

100

18

7

signed char*->float

!!! 23 !!!

161

62

32

signed char*->double

!!! 20 !!!

207

102

57

signed char*->long double

144

216

96

!!! 63 !!!

signed char*->string

!!! 12 !!!

104

23

---

int->int

!!! <1 !!!

110

22

---

float->double

!!! <1 !!!

223

113

---

double->double

!!! <1 !!!

227

111

---

int->int

!!! <1 !!!

231

122

---

int->int

!!! <1 !!!

229

121

---

char->unsigned char

!!! <1 !!!

90

8

---

char->signed char

!!! <1 !!!

88

8

---

unsigned char->char

!!! <1 !!!

89

8

---

signed char->char

!!! <1 !!!

91

9

---


Table 15.3. Performance Table (gcc-4.4)

From->To

lexical_cast

std::stringstream with construction

std::stringstream without construction

scanf/printf

string->char

!!! <1 !!!

90

7

7

string->signed char

!!! <1 !!!

88

7

8

string->unsigned char

!!! <1 !!!

88

8

14

string->int

!!! 3 !!!

103

18

15

string->short

!!! 3 !!!

105

20

15

string->long int

!!! 3 !!!

101

18

16

string->long long

!!! 3 !!!

101

18

15

string->unsigned int

!!! 3 !!!

98

23

14

string->unsigned short

!!! 3 !!!

100

17

14

string->unsigned long int

!!! 3 !!!

100

21

15

string->unsigned long long

!!! 3 !!!

99

19

15

string->bool

!!! <1 !!!

95

16

8

string->float

!!! 13 !!!

160

61

33

string->double

!!! 14 !!!

206

93

59

string->long double

128

217

96

!!! 61 !!!

char->string

!!! 7 !!!

100

17

12

unsigned char->string

!!! 7 !!!

109

17

16

signed char->string

!!! 7 !!!

99

17

12

int->string

!!! 13 !!!

110

21

15

short->string

!!! 14 !!!

110

22

17

long int->string

!!! 14 !!!

109

21

16

long long->string

!!! 13 !!!

114

20

17

unsigned int->string

!!! 13 !!!

109

23

15

unsigned short->string

!!! 14 !!!

109

23

17

unsigned long int->string

!!! 13 !!!

112

23

16

unsigned long long->string

!!! 14 !!!

109

21

17

bool->string

!!! 7 !!!

108

23

11

float->string

63

185

92

!!! 50 !!!

double->string

106

216

116

!!! 75 !!!

long double->string

118

219

119

!!! 80 !!!

char*->char

!!! 1 !!!

93

9

9

char*->signed char

!!! 1 !!!

92

9

9

char*->unsigned char

!!! 1 !!!

92

9

14

char*->int

!!! 4 !!!

107

19

15

char*->short

!!! 5 !!!

109

19

15

char*->long int

!!! 4 !!!

113

19

15

char*->long long

!!! 4 !!!

108

20

15

char*->unsigned int

!!! 4 !!!

106

19

15

char*->unsigned short

!!! 4 !!!

106

18

15

char*->unsigned long int

!!! 4 !!!

103

22

15

char*->unsigned long long

!!! 4 !!!

105

20

15

char*->bool

!!! 1 !!!

104

18

8

char*->float

!!! 15 !!!

164

62

33

char*->double

!!! 16 !!!

203

97

58

char*->long double

132

223

98

!!! 60 !!!

unsigned char*->char

!!! 2 !!!

90

9

8

unsigned char*->signed char

!!! 2 !!!

92

10

8

unsigned char*->unsigned char

!!! 2 !!!

91

9

14

unsigned char*->int

!!! 6 !!!

106

20

15

unsigned char*->short

!!! 6 !!!

106

21

15

unsigned char*->long int

!!! 6 !!!

111

19

15

unsigned char*->long long

!!! 6 !!!

107

20

15

unsigned char*->unsigned int

!!! 6 !!!

105

19

15

unsigned char*->unsigned short

!!! 6 !!!

103

18

15

unsigned char*->unsigned long int

!!! 6 !!!

106

22

14

unsigned char*->unsigned long long

!!! 6 !!!

105

20

14

unsigned char*->bool

!!! 2 !!!

106

18

8

unsigned char*->float

!!! 15 !!!

167

68

33

unsigned char*->double

!!! 17 !!!

203

99

58

unsigned char*->long double

129

216

97

!!! 61 !!!

unsigned char*->string

!!! 13 !!!

111

23

---

signed char*->char

!!! 2 !!!

92

9

8

signed char*->signed char

!!! 2 !!!

91

9

8

signed char*->unsigned char

!!! 2 !!!

91

9

14

signed char*->int

!!! 6 !!!

107

19

15

signed char*->short

!!! 6 !!!

109

24

14

signed char*->long int

!!! 6 !!!

112

19

15

signed char*->long long

!!! 5 !!!

107

20

15

signed char*->unsigned int

!!! 6 !!!

108

20

15

signed char*->unsigned short

!!! 6 !!!

104

18

15

signed char*->unsigned long int

!!! 6 !!!

102

22

15

signed char*->unsigned long long

!!! 6 !!!

104

20

15

signed char*->bool

!!! 2 !!!

104

18

8

signed char*->float

!!! 16 !!!

165

63

33

signed char*->double

!!! 16 !!!

203

98

59

signed char*->long double

129

215

98

!!! 61 !!!

signed char*->string

!!! 13 !!!

109

21

---

int->int

!!! <1 !!!

109

21

---

float->double

!!! <1 !!!

221

102

---

double->double

!!! <1 !!!

223

103

---

int->int

!!! <1 !!!

231

115

---

int->int

!!! <1 !!!

231

115

---

char->unsigned char

!!! <1 !!!

92

8

---

char->signed char

!!! <1 !!!

88

8

---

unsigned char->char

!!! <1 !!!

88

7

---

signed char->char

!!! <1 !!!

89

8

---


Table 15.4. Performance Table (gcc-4.5)

From->To

lexical_cast

std::stringstream with construction

std::stringstream without construction

scanf/printf

string->char

!!! <1 !!!

91

8

7

string->signed char

!!! <1 !!!

91

8

7

string->unsigned char

!!! <1 !!!

90

8

13

string->int

!!! 3 !!!

100

20

14

string->short

!!! 3 !!!

106

20

14

string->long int

!!! 3 !!!

100

18

14

string->long long

!!! 9 !!!

100

18

15

string->unsigned int

!!! 3 !!!

97

20

14

string->unsigned short

!!! 3 !!!

102

17

14

string->unsigned long int

!!! 3 !!!

97

21

14

string->unsigned long long

!!! 3 !!!

97

19

14

string->bool

!!! <1 !!!

95

16

7

string->float

!!! 15 !!!

157

63

32

string->double

!!! 17 !!!

203

95

59

string->long double

129

216

93

!!! 58 !!!

char->string

!!! 8 !!!

100

17

10

unsigned char->string

!!! 8 !!!

96

18

16

signed char->string

!!! 8 !!!

96

18

10

int->string

!!! 14 !!!

105

22

15

short->string

!!! 14 !!!

107

23

17

long int->string

!!! 14 !!!

109

22

17

long long->string

!!! 14 !!!

105

22

18

unsigned int->string

!!! 14 !!!

105

25

15

unsigned short->string

!!! 15 !!!

105

23

17

unsigned long int->string

!!! 14 !!!

109

24

17

unsigned long long->string

!!! 14 !!!

102

23

17

bool->string

!!! 8 !!!

104

23

12

float->string

66

181

92

!!! 49 !!!

double->string

107

215

120

!!! 75 !!!

long double->string

117

221

125

!!! 79 !!!

char*->char

!!! 1 !!!

89

9

7

char*->signed char

!!! 1 !!!

90

9

7

char*->unsigned char

!!! 2 !!!

90

9

13

char*->int

!!! 7 !!!

103

20

15

char*->short

!!! 6 !!!

102

29

14

char*->long int

!!! 7 !!!

101

20

15

char*->long long

!!! 6 !!!

102

20

14

char*->unsigned int

!!! 6 !!!

99

19

14

char*->unsigned short

!!! 6 !!!

101

18

14

char*->unsigned long int

!!! 6 !!!

102

22

14

char*->unsigned long long

!!! 6 !!!

101

21

14

char*->bool

!!! 3 !!!

98

18

7

char*->float

!!! 18 !!!

162

63

31

char*->double

!!! 17 !!!

203

96

58

char*->long double

135

214

98

!!! 58 !!!

unsigned char*->char

!!! 2 !!!

87

9

7

unsigned char*->signed char

!!! 2 !!!

87

9

7

unsigned char*->unsigned char

!!! 3 !!!

87

9

13

unsigned char*->int

!!! 6 !!!

105

20

14

unsigned char*->short

!!! 6 !!!

102

21

14

unsigned char*->long int

!!! 6 !!!

101

20

14

unsigned char*->long long

!!! 6 !!!

102

20

14

unsigned char*->unsigned int

!!! 6 !!!

99

19

14

unsigned char*->unsigned short

!!! 6 !!!

100

18

14

unsigned char*->unsigned long int

!!! 6 !!!

101

24

14

unsigned char*->unsigned long long

!!! 6 !!!

100

20

14

unsigned char*->bool

!!! 3 !!!

99

18

8

unsigned char*->float

!!! 17 !!!

164

64

32

unsigned char*->double

!!! 18 !!!

201

94

58

unsigned char*->long double

133

217

95

!!! 60 !!!

unsigned char*->string

!!! 14 !!!

103

23

---

signed char*->char

!!! 3 !!!

88

10

8

signed char*->signed char

!!! 2 !!!

87

10

7

signed char*->unsigned char

!!! 3 !!!

87

9

13

signed char*->int

!!! 6 !!!

104

20

14

signed char*->short

!!! 6 !!!

105

21

14

signed char*->long int

!!! 6 !!!

104

20

15

signed char*->long long

!!! 6 !!!

106

20

14

signed char*->unsigned int

!!! 6 !!!

99

20

14

signed char*->unsigned short

!!! 6 !!!

100

18

14

signed char*->unsigned long int

!!! 6 !!!

102

23

14

signed char*->unsigned long long

!!! 6 !!!

103

20

14

signed char*->bool

!!! 3 !!!

99

18

7

signed char*->float

!!! 18 !!!

159

60

32

signed char*->double

!!! 18 !!!

203

95

57

signed char*->long double

129

213

97

!!! 56 !!!

signed char*->string

!!! 14 !!!

105

22

---

int->int

!!! <1 !!!

109

22

---

float->double

!!! <1 !!!

226

104

---

double->double

!!! <1 !!!

229

103

---

int->int

!!! <1 !!!

225

115

---

int->int

!!! <1 !!!

227

115

---

char->unsigned char

!!! <1 !!!

90

8

---

char->signed char

!!! <1 !!!

84

8

---

unsigned char->char

!!! <1 !!!

88

8

---

signed char->char

!!! <1 !!!

89

8

---


Table 15.5. Performance Table (gcc-4.6)

From->To

lexical_cast

std::stringstream with construction

std::stringstream without construction

scanf/printf

string->char

!!! <1 !!!

94

8

7

string->signed char

!!! <1 !!!

96

9

7

string->unsigned char

!!! <1 !!!

96

8

13

string->int

!!! 3 !!!

110

18

16

string->short

!!! 3 !!!

111

18

16

string->long int

!!! 3 !!!

109

18

15

string->long long

!!! 3 !!!

111

18

15

string->unsigned int

!!! 3 !!!

110

20

15

string->unsigned short

!!! 3 !!!

111

18

15

string->unsigned long int

!!! 3 !!!

109

18

15

string->unsigned long long

!!! 3 !!!

114

19

15

string->bool

!!! <1 !!!

106

17

8

string->float

!!! 13 !!!

175

70

33

string->double

!!! 14 !!!

182

81

58

string->long double

118

190

87

!!! 58 !!!

char->string

!!! 8 !!!

118

21

12

unsigned char->string

!!! 8 !!!

109

18

16

signed char->string

!!! 8 !!!

108

18

12

int->string

20

121

21

!!! 16 !!!

short->string

!!! 15 !!!

120

22

17

long int->string

!!! 15 !!!

120

22

16

long long->string

!!! 15 !!!

120

22

17

unsigned int->string

!!! 15 !!!

120

22

16

unsigned short->string

!!! 15 !!!

120

22

18

unsigned long int->string

16

118

22

!!! 15 !!!

unsigned long long->string

!!! 15 !!!

117

21

17

bool->string

!!! 8 !!!

117

23

10

float->string

77

218

105

!!! 50 !!!

double->string

108

247

129

!!! 73 !!!

long double->string

120

250

131

!!! 79 !!!

char*->char

!!! 2 !!!

99

9

7

char*->signed char

!!! 2 !!!

98

9

8

char*->unsigned char

!!! 2 !!!

98

9

13

char*->int

!!! 6 !!!

115

22

15

char*->short

!!! 6 !!!

114

22

15

char*->long int

!!! 6 !!!

114

22

16

char*->long long

!!! 6 !!!

119

22

15

char*->unsigned int

!!! 6 !!!

114

20

15

char*->unsigned short

!!! 6 !!!

116

20

15

char*->unsigned long int

!!! 6 !!!

117

22

15

char*->unsigned long long

!!! 6 !!!

118

22

15

char*->bool

!!! 3 !!!

113

18

8

char*->float

!!! 15 !!!

180

78

32

char*->double

!!! 16 !!!

185

89

58

char*->long double

119

193

91

!!! 60 !!!

unsigned char*->char

!!! 2 !!!

99

9

8

unsigned char*->signed char

!!! 2 !!!

99

10

8

unsigned char*->unsigned char

!!! 2 !!!

100

9

15

unsigned char*->int

!!! 6 !!!

118

22

15

unsigned char*->short

!!! 6 !!!

117

26

15

unsigned char*->long int

!!! 6 !!!

119

21

15

unsigned char*->long long

!!! 6 !!!

118

21

14

unsigned char*->unsigned int

!!! 6 !!!

115

22

14

unsigned char*->unsigned short

!!! 6 !!!

117

20

15

unsigned char*->unsigned long int

!!! 6 !!!

115

21

15

unsigned char*->unsigned long long

!!! 6 !!!

117

22

15

unsigned char*->bool

!!! 3 !!!

112

18

8

unsigned char*->float

!!! 15 !!!

181

78

33

unsigned char*->double

!!! 16 !!!

185

92

59

unsigned char*->long double

120

190

89

!!! 58 !!!

unsigned char*->string

!!! 14 !!!

121

22

---

signed char*->char

!!! 2 !!!

99

9

9

signed char*->signed char

!!! 2 !!!

98

9

8

signed char*->unsigned char

!!! 2 !!!

98

9

14

signed char*->int

!!! 6 !!!

119

22

16

signed char*->short

!!! 6 !!!

115

22

15

signed char*->long int

!!! 6 !!!

119

22

15

signed char*->long long

!!! 6 !!!

117

22

15

signed char*->unsigned int

!!! 6 !!!

117

23

15

signed char*->unsigned short

!!! 6 !!!

117

21

14

signed char*->unsigned long int

!!! 7 !!!

119

24

15

signed char*->unsigned long long

!!! 6 !!!

116

22

15

signed char*->bool

!!! 3 !!!

111

18

8

signed char*->float

!!! 16 !!!

180

78

33

signed char*->double

!!! 16 !!!

185

89

59

signed char*->long double

120

191

91

!!! 59 !!!

signed char*->string

!!! 14 !!!

122

23

---

int->int

!!! <1 !!!

120

22

---

float->double

!!! <1 !!!

242

115

---

double->double

!!! <1 !!!

243

115

---

int->int

!!! <1 !!!

265

141

---

int->int

!!! <1 !!!

266

140

---

char->unsigned char

!!! <1 !!!

95

8

---

char->signed char

!!! <1 !!!

95

8

---

unsigned char->char

!!! <1 !!!

94

8

---

signed char->char

!!! <1 !!!

94

8

---



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