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gbench-stream/benchmark/src/commandlineflags.cc
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// Copyright 2015 Google Inc. All rights reserved.
//
// 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.
#include "commandlineflags.h"
#include <algorithm>
#include <cctype>
#include <cstdlib>
#include <cstring>
#include <iostream>
#include <limits>
#include <map>
#include <utility>
#include "../src/string_util.h"
namespace benchmark {
namespace {
// Parses 'str' for a 32-bit signed integer. If successful, writes
// the result to *value and returns true; otherwise leaves *value
// unchanged and returns false.
bool ParseInt32(const std::string& src_text, const char* str, int32_t* value) {
// Parses the environment variable as a decimal integer.
char* end = nullptr;
const long long_value = strtol(str, &end, 10); // NOLINT
// Has strtol() consumed all characters in the string?
if (*end != '\0') {
// No - an invalid character was encountered.
std::cerr << src_text << " is expected to be a 32-bit integer, "
<< "but actually has value \"" << str << "\".\n";
return false;
}
// Is the parsed value in the range of an Int32?
const int32_t result = static_cast<int32_t>(long_value);
if (long_value == std::numeric_limits<long>::max() ||
long_value == std::numeric_limits<long>::min() ||
// The parsed value overflows as a long. (strtol() returns
// LONG_MAX or LONG_MIN when the input overflows.)
result != long_value
// The parsed value overflows as an Int32.
) {
std::cerr << src_text << " is expected to be a 32-bit integer, "
<< "but actually has value \"" << str << "\", "
<< "which overflows.\n";
return false;
}
*value = result;
return true;
}
// Parses 'str' for a double. If successful, writes the result to *value and
// returns true; otherwise leaves *value unchanged and returns false.
bool ParseDouble(const std::string& src_text, const char* str, double* value) {
// Parses the environment variable as a decimal integer.
char* end = nullptr;
const double double_value = strtod(str, &end); // NOLINT
// Has strtol() consumed all characters in the string?
if (*end != '\0') {
// No - an invalid character was encountered.
std::cerr << src_text << " is expected to be a double, "
<< "but actually has value \"" << str << "\".\n";
return false;
}
*value = double_value;
return true;
}
// Parses 'str' into KV pairs. If successful, writes the result to *value and
// returns true; otherwise leaves *value unchanged and returns false.
bool ParseKvPairs(const std::string& src_text, const char* str,
std::map<std::string, std::string>* value) {
std::map<std::string, std::string> kvs;
for (const auto& kvpair : StrSplit(str, ',')) {
const auto kv = StrSplit(kvpair, '=');
if (kv.size() != 2) {
std::cerr << src_text << " is expected to be a comma-separated list of "
<< "<key>=<value> strings, but actually has value \"" << str
<< "\".\n";
return false;
}
if (!kvs.emplace(kv[0], kv[1]).second) {
std::cerr << src_text << " is expected to contain unique keys but key \""
<< kv[0] << "\" was repeated.\n";
return false;
}
}
*value = kvs;
return true;
}
// Returns the name of the environment variable corresponding to the
// given flag. For example, FlagToEnvVar("foo") will return
// "BENCHMARK_FOO" in the open-source version.
static std::string FlagToEnvVar(const char* flag) {
const std::string flag_str(flag);
std::string env_var;
for (size_t i = 0; i != flag_str.length(); ++i)
env_var += static_cast<char>(::toupper(flag_str.c_str()[i]));
return env_var;
}
} // namespace
BENCHMARK_EXPORT
bool BoolFromEnv(const char* flag, bool default_val) {
const std::string env_var = FlagToEnvVar(flag);
const char* const value_str = getenv(env_var.c_str());
return value_str == nullptr ? default_val : IsTruthyFlagValue(value_str);
}
BENCHMARK_EXPORT
int32_t Int32FromEnv(const char* flag, int32_t default_val) {
const std::string env_var = FlagToEnvVar(flag);
const char* const value_str = getenv(env_var.c_str());
int32_t value = default_val;
if (value_str == nullptr ||
!ParseInt32(std::string("Environment variable ") + env_var, value_str,
&value)) {
return default_val;
}
return value;
}
BENCHMARK_EXPORT
double DoubleFromEnv(const char* flag, double default_val) {
const std::string env_var = FlagToEnvVar(flag);
const char* const value_str = getenv(env_var.c_str());
double value = default_val;
if (value_str == nullptr ||
!ParseDouble(std::string("Environment variable ") + env_var, value_str,
&value)) {
return default_val;
}
return value;
}
BENCHMARK_EXPORT
const char* StringFromEnv(const char* flag, const char* default_val) {
const std::string env_var = FlagToEnvVar(flag);
const char* const value = getenv(env_var.c_str());
return value == nullptr ? default_val : value;
}
BENCHMARK_EXPORT
std::map<std::string, std::string> KvPairsFromEnv(
const char* flag, std::map<std::string, std::string> default_val) {
const std::string env_var = FlagToEnvVar(flag);
const char* const value_str = getenv(env_var.c_str());
if (value_str == nullptr) return default_val;
std::map<std::string, std::string> value;
if (!ParseKvPairs("Environment variable " + env_var, value_str, &value)) {
return default_val;
}
return value;
}
// Parses a string as a command line flag. The string should have
// the format "--flag=value". When def_optional is true, the "=value"
// part can be omitted.
//
// Returns the value of the flag, or nullptr if the parsing failed.
const char* ParseFlagValue(const char* str, const char* flag,
bool def_optional) {
// str and flag must not be nullptr.
if (str == nullptr || flag == nullptr) return nullptr;
// The flag must start with "--".
const std::string flag_str = std::string("--") + std::string(flag);
const size_t flag_len = flag_str.length();
if (strncmp(str, flag_str.c_str(), flag_len) != 0) return nullptr;
// Skips the flag name.
const char* flag_end = str + flag_len;
// When def_optional is true, it's OK to not have a "=value" part.
if (def_optional && (flag_end[0] == '\0')) return flag_end;
// If def_optional is true and there are more characters after the
// flag name, or if def_optional is false, there must be a '=' after
// the flag name.
if (flag_end[0] != '=') return nullptr;
// Returns the string after "=".
return flag_end + 1;
}
BENCHMARK_EXPORT
bool ParseBoolFlag(const char* str, const char* flag, bool* value) {
// Gets the value of the flag as a string.
const char* const value_str = ParseFlagValue(str, flag, true);
// Aborts if the parsing failed.
if (value_str == nullptr) return false;
// Converts the string value to a bool.
*value = IsTruthyFlagValue(value_str);
return true;
}
BENCHMARK_EXPORT
bool ParseInt32Flag(const char* str, const char* flag, int32_t* value) {
// Gets the value of the flag as a string.
const char* const value_str = ParseFlagValue(str, flag, false);
// Aborts if the parsing failed.
if (value_str == nullptr) return false;
// Sets *value to the value of the flag.
return ParseInt32(std::string("The value of flag --") + flag, value_str,
value);
}
BENCHMARK_EXPORT
bool ParseDoubleFlag(const char* str, const char* flag, double* value) {
// Gets the value of the flag as a string.
const char* const value_str = ParseFlagValue(str, flag, false);
// Aborts if the parsing failed.
if (value_str == nullptr) return false;
// Sets *value to the value of the flag.
return ParseDouble(std::string("The value of flag --") + flag, value_str,
value);
}
BENCHMARK_EXPORT
bool ParseStringFlag(const char* str, const char* flag, std::string* value) {
// Gets the value of the flag as a string.
const char* const value_str = ParseFlagValue(str, flag, false);
// Aborts if the parsing failed.
if (value_str == nullptr) return false;
*value = value_str;
return true;
}
BENCHMARK_EXPORT
bool ParseKeyValueFlag(const char* str, const char* flag,
std::map<std::string, std::string>* value) {
const char* const value_str = ParseFlagValue(str, flag, false);
if (value_str == nullptr) return false;
for (const auto& kvpair : StrSplit(value_str, ',')) {
const auto kv = StrSplit(kvpair, '=');
if (kv.size() != 2) return false;
value->emplace(kv[0], kv[1]);
}
return true;
}
BENCHMARK_EXPORT
bool IsFlag(const char* str, const char* flag) {
return (ParseFlagValue(str, flag, true) != nullptr);
}
BENCHMARK_EXPORT
bool IsTruthyFlagValue(const std::string& value) {
if (value.size() == 1) {
char v = value[0];
return isalnum(v) &&
!(v == '0' || v == 'f' || v == 'F' || v == 'n' || v == 'N');
} else if (!value.empty()) {
std::string value_lower(value);
std::transform(value_lower.begin(), value_lower.end(), value_lower.begin(),
[](char c) { return static_cast<char>(::tolower(c)); });
return !(value_lower == "false" || value_lower == "no" ||
value_lower == "off");
} else
return true;
}
} // end namespace benchmark
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