string_util.cc

#include"string_util.h"

#include<array>
#ifdef BENCHMARK_STL_ANDROID_GNUSTL
#include<cerrno>
#endif
#include<cmath>
#include<cstdarg>
#include<cstdio>
#include<memory>
#include<sstream>

#include"arraysize.h"
#include"benchmark/benchmark.h"

namespacebenchmark {
namespace {
// kilo, Mega, Giga, Tera, Peta, Exa, Zetta, Yotta.
constchar* constkBigSIUnits[] = {"k", "M", "G", "T", "P", "E", "Z", "Y"};
// Kibi, Mebi, Gibi, Tebi, Pebi, Exbi, Zebi, Yobi.
constchar* constkBigIECUnits[] = {"Ki", "Mi", "Gi", "Ti",
"Pi", "Ei", "Zi", "Yi"};
// milli, micro, nano, pico, femto, atto, zepto, yocto.
constchar* constkSmallSIUnits[] = {"m", "u", "n", "p", "f", "a", "z", "y"};

// We require that all three arrays have the same size.
static_assert(arraysize(kBigSIUnits) == arraysize(kBigIECUnits),
"SI and IEC unit arrays must be the same size");
static_assert(arraysize(kSmallSIUnits) == arraysize(kBigSIUnits),
"Small SI and Big SI unit arrays must be the same size");

staticconstint64_tkUnitsSize = arraysize(kBigSIUnits);

voidToExponentAndMantissa(double val, int precision, double one_k,
 std::string* mantissa, int64_t* exponent) {
 std::stringstream mantissa_stream;

if (val < 0) {
 mantissa_stream << "-";
 val = -val;
 }

// Adjust threshold so that it never excludes things which can't be rendered
// in 'precision' digits.
constdouble adjusted_threshold =
std::max(1.0, 1.0 / std::pow(10.0, precision));
constdouble big_threshold = (adjusted_threshold * one_k) - 1;
constdouble small_threshold = adjusted_threshold;
// Values in ]simple_threshold,small_threshold[ will be printed as-is
constdouble simple_threshold = 0.01;

if (val > big_threshold) {
// Positive powers
double scaled = val;
for (size_t i = 0; i < arraysize(kBigSIUnits); ++i) {
 scaled /= one_k;
if (scaled <= big_threshold) {
 mantissa_stream << scaled;
 *exponent = i + 1;
 *mantissa = mantissa_stream.str();
return;
 }
 }
 mantissa_stream << val;
 *exponent = 0;
 } elseif (val < small_threshold) {
// Negative powers
if (val < simple_threshold) {
double scaled = val;
for (size_t i = 0; i < arraysize(kSmallSIUnits); ++i) {
 scaled *= one_k;
if (scaled >= small_threshold) {
 mantissa_stream << scaled;
 *exponent = -static_cast<int64_t>(i + 1);
 *mantissa = mantissa_stream.str();
return;
 }
 }
 }
 mantissa_stream << val;
 *exponent = 0;
 } else {
 mantissa_stream << val;
 *exponent = 0;
 }
 *mantissa = mantissa_stream.str();
}

std::string ExponentToPrefix(int64_t exponent, bool iec) {
if (exponent == 0) return"";

constint64_tindex = (exponent > 0 ? exponent - 1 : -exponent - 1);
if (index >= kUnitsSize) return"";

constchar* const* array =
 (exponent > 0 ? (iec ? kBigIECUnits : kBigSIUnits) : kSmallSIUnits);

returnstd::string(array[index]);
}

std::string ToBinaryStringFullySpecified(double value, int precision,
 Counter::OneK one_k) {
 std::string mantissa;
int64_t exponent;
ToExponentAndMantissa(value, precision,
 one_k == Counter::kIs1024 ? 1024.0 : 1000.0, &mantissa,
 &exponent);
return mantissa + ExponentToPrefix(exponent, one_k == Counter::kIs1024);
}

std::string StrFormatImp(constchar* msg, va_list args) {
// we might need a second shot at this, so pre-emptivly make a copy
va_list args_cp;
va_copy(args_cp, args);

// TODO(ericwf): use std::array for first attempt to avoid one memory
// allocation guess what the size might be
 std::array<char, 256> local_buff;

// 2015-10-08: vsnprintf is used instead of snd::vsnprintf due to a limitation
// in the android-ndk
auto ret = vsnprintf(local_buff.data(), local_buff.size(), msg, args_cp);

va_end(args_cp);

// handle empty expansion
if (ret == 0) return std::string{};
if (static_cast<std::size_t>(ret) < local_buff.size())
returnstd::string(local_buff.data());

// we did not provide a long enough buffer on our first attempt.
// add 1 to size to account for null-byte in size cast to prevent overflow
 std::size_t size = static_cast<std::size_t>(ret) + 1;
auto buff_ptr = std::unique_ptr<char[]>(newchar[size]);
// 2015-10-08: vsnprintf is used instead of snd::vsnprintf due to a limitation
// in the android-ndk
vsnprintf(buff_ptr.get(), size, msg, args);
returnstd::string(buff_ptr.get());
}

} // end namespace

std::string HumanReadableNumber(double n, Counter::OneK one_k) {
returnToBinaryStringFullySpecified(n, 1, one_k);
}

std::string StrFormat(constchar* format, ...) {
va_list args;
va_start(args, format);
 std::string tmp = StrFormatImp(format, args);
va_end(args);
return tmp;
}

std::vector<std::string> StrSplit(const std::string& str, char delim) {
if (str.empty()) return {};
 std::vector<std::string> ret;
size_t first = 0;
size_t next = str.find(delim);
for (; next != std::string::npos;
 first = next + 1, next = str.find(delim, first)) {
 ret.push_back(str.substr(first, next - first));
 }
 ret.push_back(str.substr(first));
return ret;
}

#ifdef BENCHMARK_STL_ANDROID_GNUSTL
/*
 * GNU STL in Android NDK lacks support for some C++11 functions, including
 * stoul, stoi, stod. We reimplement them here using C functions strtoul,
 * strtol, strtod. Note that reimplemented functions are in benchmark::
 * namespace, not std:: namespace.
*/
unsignedlongstoul(const std::string& str, size_t* pos, int base) {
/* Record previous errno */
constint oldErrno = errno;
 errno = 0;

constchar* strStart = str.c_str();
char* strEnd = const_cast<char*>(strStart);
constunsignedlong result = strtoul(strStart, &strEnd, base);

constint strtoulErrno = errno;
/* Restore previous errno */
 errno = oldErrno;

/* Check for errors and return */
if (strtoulErrno == ERANGE) {
throwstd::out_of_range("stoul failed: " + str +
" is outside of range of unsigned long");
 } elseif (strEnd == strStart || strtoulErrno != 0) {
throwstd::invalid_argument("stoul failed: " + str + " is not an integer");
 }
if (pos != nullptr) {
 *pos = static_cast<size_t>(strEnd - strStart);
 }
return result;
}

intstoi(const std::string& str, size_t* pos, int base) {
/* Record previous errno */
constint oldErrno = errno;
 errno = 0;

constchar* strStart = str.c_str();
char* strEnd = const_cast<char*>(strStart);
constlong result = strtol(strStart, &strEnd, base);

constint strtolErrno = errno;
/* Restore previous errno */
 errno = oldErrno;

/* Check for errors and return */
if (strtolErrno == ERANGE || long(int(result)) != result) {
throwstd::out_of_range("stoul failed: " + str +
" is outside of range of int");
 } elseif (strEnd == strStart || strtolErrno != 0) {
throwstd::invalid_argument("stoul failed: " + str + " is not an integer");
 }
if (pos != nullptr) {
 *pos = static_cast<size_t>(strEnd - strStart);
 }
returnint(result);
}

doublestod(const std::string& str, size_t* pos) {
/* Record previous errno */
constint oldErrno = errno;
 errno = 0;

constchar* strStart = str.c_str();
char* strEnd = const_cast<char*>(strStart);
constdouble result = strtod(strStart, &strEnd);

/* Restore previous errno */
constint strtodErrno = errno;
 errno = oldErrno;

/* Check for errors and return */
if (strtodErrno == ERANGE) {
throwstd::out_of_range("stoul failed: " + str +
" is outside of range of int");
 } elseif (strEnd == strStart || strtodErrno != 0) {
throwstd::invalid_argument("stoul failed: " + str + " is not an integer");
 }
if (pos != nullptr) {
 *pos = static_cast<size_t>(strEnd - strStart);
 }
return result;
}
#endif

} // end namespace benchmark