1#include "string_util.h"
2
3#include <array>
4#include <cmath>
5#include <cstdarg>
6#include <cstdio>
7#include <memory>
8#include <sstream>
9
10#include "arraysize.h"
11
12namespace benchmark {
13namespace {
14
15// kilo, Mega, Giga, Tera, Peta, Exa, Zetta, Yotta.
16const char kBigSIUnits[] = "kMGTPEZY";
17// Kibi, Mebi, Gibi, Tebi, Pebi, Exbi, Zebi, Yobi.
18const char kBigIECUnits[] = "KMGTPEZY";
19// milli, micro, nano, pico, femto, atto, zepto, yocto.
20const char kSmallSIUnits[] = "munpfazy";
21
22// We require that all three arrays have the same size.
23static_assert(arraysize(kBigSIUnits) == arraysize(kBigIECUnits),
24 "SI and IEC unit arrays must be the same size");
25static_assert(arraysize(kSmallSIUnits) == arraysize(kBigSIUnits),
26 "Small SI and Big SI unit arrays must be the same size");
27
28static const int64_t kUnitsSize = arraysize(kBigSIUnits);
29
30void ToExponentAndMantissa(double val, double thresh, int precision,
31 double one_k, std::string* mantissa,
32 int64_t* exponent) {
33 std::stringstream mantissa_stream;
34
35 if (val < 0) {
36 mantissa_stream << "-";
37 val = -val;
38 }
39
40 // Adjust threshold so that it never excludes things which can't be rendered
41 // in 'precision' digits.
42 const double adjusted_threshold =
43 std::max(thresh, 1.0 / std::pow(10.0, precision));
44 const double big_threshold = adjusted_threshold * one_k;
45 const double small_threshold = adjusted_threshold;
46 // Values in ]simple_threshold,small_threshold[ will be printed as-is
47 const double simple_threshold = 0.01;
48
49 if (val > big_threshold) {
50 // Positive powers
51 double scaled = val;
52 for (size_t i = 0; i < arraysize(kBigSIUnits); ++i) {
53 scaled /= one_k;
54 if (scaled <= big_threshold) {
55 mantissa_stream << scaled;
56 *exponent = i + 1;
57 *mantissa = mantissa_stream.str();
58 return;
59 }
60 }
61 mantissa_stream << val;
62 *exponent = 0;
63 } else if (val < small_threshold) {
64 // Negative powers
65 if (val < simple_threshold) {
66 double scaled = val;
67 for (size_t i = 0; i < arraysize(kSmallSIUnits); ++i) {
68 scaled *= one_k;
69 if (scaled >= small_threshold) {
70 mantissa_stream << scaled;
71 *exponent = -static_cast<int64_t>(i + 1);
72 *mantissa = mantissa_stream.str();
73 return;
74 }
75 }
76 }
77 mantissa_stream << val;
78 *exponent = 0;
79 } else {
80 mantissa_stream << val;
81 *exponent = 0;
82 }
83 *mantissa = mantissa_stream.str();
84}
85
86std::string ExponentToPrefix(int64_t exponent, bool iec) {
87 if (exponent == 0) return "";
88
89 const int64_t index = (exponent > 0 ? exponent - 1 : -exponent - 1);
90 if (index >= kUnitsSize) return "";
91
92 const char* array =
93 (exponent > 0 ? (iec ? kBigIECUnits : kBigSIUnits) : kSmallSIUnits);
94 if (iec)
95 return array[index] + std::string("i");
96 else
97 return std::string(1, array[index]);
98}
99
100std::string ToBinaryStringFullySpecified(double value, double threshold,
101 int precision, double one_k = 1024.0) {
102 std::string mantissa;
103 int64_t exponent;
104 ToExponentAndMantissa(value, threshold, precision, one_k, &mantissa,
105 &exponent);
106 return mantissa + ExponentToPrefix(exponent, false);
107}
108
109} // end namespace
110
111void AppendHumanReadable(int n, std::string* str) {
112 std::stringstream ss;
113 // Round down to the nearest SI prefix.
114 ss << ToBinaryStringFullySpecified(n, 1.0, 0);
115 *str += ss.str();
116}
117
118std::string HumanReadableNumber(double n, double one_k) {
119 // 1.1 means that figures up to 1.1k should be shown with the next unit down;
120 // this softens edge effects.
121 // 1 means that we should show one decimal place of precision.
122 return ToBinaryStringFullySpecified(n, 1.1, 1, one_k);
123}
124
125std::string StrFormatImp(const char* msg, va_list args) {
126 // we might need a second shot at this, so pre-emptivly make a copy
127 va_list args_cp;
128 va_copy(args_cp, args);
129
130 // TODO(ericwf): use std::array for first attempt to avoid one memory
131 // allocation guess what the size might be
132 std::array<char, 256> local_buff;
133 std::size_t size = local_buff.size();
134 // 2015-10-08: vsnprintf is used instead of snd::vsnprintf due to a limitation
135 // in the android-ndk
136 auto ret = vsnprintf(local_buff.data(), size, msg, args_cp);
137
138 va_end(args_cp);
139
140 // handle empty expansion
141 if (ret == 0) return std::string{};
142 if (static_cast<std::size_t>(ret) < size)
143 return std::string(local_buff.data());
144
145 // we did not provide a long enough buffer on our first attempt.
146 // add 1 to size to account for null-byte in size cast to prevent overflow
147 size = static_cast<std::size_t>(ret) + 1;
148 auto buff_ptr = std::unique_ptr<char[]>(new char[size]);
149 // 2015-10-08: vsnprintf is used instead of snd::vsnprintf due to a limitation
150 // in the android-ndk
151 ret = vsnprintf(buff_ptr.get(), size, msg, args);
152 return std::string(buff_ptr.get());
153}
154
155std::string StrFormat(const char* format, ...) {
156 va_list args;
157 va_start(args, format);
158 std::string tmp = StrFormatImp(format, args);
159 va_end(args);
160 return tmp;
161}
162
163#ifdef BENCHMARK_STL_ANDROID_GNUSTL
164/*
165 * GNU STL in Android NDK lacks support for some C++11 functions, including
166 * stoul, stoi, stod. We reimplement them here using C functions strtoul,
167 * strtol, strtod. Note that reimplemented functions are in benchmark::
168 * namespace, not std:: namespace.
169 */
170unsigned long stoul(const std::string& str, size_t* pos, int base) {
171 /* Record previous errno */
172 const int oldErrno = errno;
173 errno = 0;
174
175 const char* strStart = str.c_str();
176 char* strEnd = const_cast<char*>(strStart);
177 const unsigned long result = strtoul(strStart, &strEnd, base);
178
179 const int strtoulErrno = errno;
180 /* Restore previous errno */
181 errno = oldErrno;
182
183 /* Check for errors and return */
184 if (strtoulErrno == ERANGE) {
185 throw std::out_of_range(
186 "stoul failed: " + str + " is outside of range of unsigned long");
187 } else if (strEnd == strStart || strtoulErrno != 0) {
188 throw std::invalid_argument(
189 "stoul failed: " + str + " is not an integer");
190 }
191 if (pos != nullptr) {
192 *pos = static_cast<size_t>(strEnd - strStart);
193 }
194 return result;
195}
196
197int stoi(const std::string& str, size_t* pos, int base) {
198 /* Record previous errno */
199 const int oldErrno = errno;
200 errno = 0;
201
202 const char* strStart = str.c_str();
203 char* strEnd = const_cast<char*>(strStart);
204 const long result = strtol(strStart, &strEnd, base);
205
206 const int strtolErrno = errno;
207 /* Restore previous errno */
208 errno = oldErrno;
209
210 /* Check for errors and return */
211 if (strtolErrno == ERANGE || long(int(result)) != result) {
212 throw std::out_of_range(
213 "stoul failed: " + str + " is outside of range of int");
214 } else if (strEnd == strStart || strtolErrno != 0) {
215 throw std::invalid_argument(
216 "stoul failed: " + str + " is not an integer");
217 }
218 if (pos != nullptr) {
219 *pos = static_cast<size_t>(strEnd - strStart);
220 }
221 return int(result);
222}
223
224double stod(const std::string& str, size_t* pos) {
225 /* Record previous errno */
226 const int oldErrno = errno;
227 errno = 0;
228
229 const char* strStart = str.c_str();
230 char* strEnd = const_cast<char*>(strStart);
231 const double result = strtod(strStart, &strEnd);
232
233 /* Restore previous errno */
234 const int strtodErrno = errno;
235 errno = oldErrno;
236
237 /* Check for errors and return */
238 if (strtodErrno == ERANGE) {
239 throw std::out_of_range(
240 "stoul failed: " + str + " is outside of range of int");
241 } else if (strEnd == strStart || strtodErrno != 0) {
242 throw std::invalid_argument(
243 "stoul failed: " + str + " is not an integer");
244 }
245 if (pos != nullptr) {
246 *pos = static_cast<size_t>(strEnd - strStart);
247 }
248 return result;
249}
250#endif
251
252} // end namespace benchmark
253