# Crow: include/crow/utility.h Source File

utility.h
#pragma once
#include <cstdint>
#include <stdexcept>
#include <tuple>
#include <type_traits>
#include <cstring>
#include <cctype>
#include <functional>
#include <string>
#include <sstream>
#include <unordered_map>
#include <random>
#include <algorithm>
#include "crow/settings.h"
#if defined(CROW_CAN_USE_CPP17) && !defined(CROW_FILESYSTEM_IS_EXPERIMENTAL)
#include <filesystem>
#endif
// TODO(EDev): Adding C++20's [[likely]] and [[unlikely]] attributes might be useful
#if defined(__GNUG__) || defined(__clang__)
#define CROW_LIKELY(X) __builtin_expect(!!(X), 1)
#define CROW_UNLIKELY(X) __builtin_expect(!!(X), 0)
#else
#define CROW_LIKELY(X) (X)
#define CROW_UNLIKELY(X) (X)
#endif
namespace crow
{
/// @cond SKIP
namespace black_magic
{
#ifndef CROW_MSVC_WORKAROUND
/// Out of Range Exception for const_str
struct OutOfRange
{
OutOfRange(unsigned /*pos*/, unsigned /*length*/) {}
};
/// Helper function to throw an exception if i is larger than len
constexpr unsigned requires_in_range(unsigned i, unsigned len)
{
return i >= len ? throw OutOfRange(i, len) : i;
}
/// A constant string implementation.
class const_str
{
const char* const begin_;
unsigned size_;
public:
template<unsigned N>
constexpr const_str(const char (&arr)[N]):
begin_(arr), size_(N - 1)
{
static_assert(N >= 1, "not a string literal");
}
constexpr char operator[](unsigned i) const
{
return requires_in_range(i, size_), begin_[i];
}
constexpr operator const char*() const
{
return begin_;
}
constexpr const char* begin() const { return begin_; }
constexpr const char* end() const { return begin_ + size_; }
constexpr unsigned size() const
{
return size_;
}
};
constexpr unsigned find_closing_tag(const_str s, unsigned p)
{
return s[p] == '>' ? p : find_closing_tag(s, p + 1);
}
/// Check that the CROW_ROUTE string is valid
constexpr bool is_valid(const_str s, unsigned i = 0, int f = 0)
{
return i == s.size() ? f == 0 :
f < 0 || f >= 2 ? false :
s[i] == '<' ? is_valid(s, i + 1, f + 1) :
s[i] == '>' ? is_valid(s, i + 1, f - 1) :
is_valid(s, i + 1, f);
}
constexpr bool is_equ_p(const char* a, const char* b, unsigned n)
{
return *a == 0 && *b == 0 && n == 0 ? true :
(*a == 0 || *b == 0) ? false :
n == 0 ? true :
*a != *b ? false :
is_equ_p(a + 1, b + 1, n - 1);
}
constexpr bool is_equ_n(const_str a, unsigned ai, const_str b, unsigned bi, unsigned n)
{
return ai + n > a.size() || bi + n > b.size() ? false :
n == 0 ? true :
a[ai] != b[bi] ? false :
is_equ_n(a, ai + 1, b, bi + 1, n - 1);
}
constexpr bool is_int(const_str s, unsigned i)
{
return is_equ_n(s, i, "<int>", 0, 5);
}
constexpr bool is_uint(const_str s, unsigned i)
{
return is_equ_n(s, i, "<uint>", 0, 6);
}
constexpr bool is_float(const_str s, unsigned i)
{
return is_equ_n(s, i, "<float>", 0, 7) ||
is_equ_n(s, i, "<double>", 0, 8);
}
constexpr bool is_str(const_str s, unsigned i)
{
return is_equ_n(s, i, "<str>", 0, 5) ||
is_equ_n(s, i, "<string>", 0, 8);
}
constexpr bool is_path(const_str s, unsigned i)
{
return is_equ_n(s, i, "<path>", 0, 6);
}
#endif
template<typename T>
struct parameter_tag
{
static const int value = 0;
};
#define CROW_INTERNAL_PARAMETER_TAG(t, i) \
template<> \
struct parameter_tag<t> \
{ \
static const int value = i; \
}
CROW_INTERNAL_PARAMETER_TAG(int, 1);
CROW_INTERNAL_PARAMETER_TAG(char, 1);
CROW_INTERNAL_PARAMETER_TAG(short, 1);
CROW_INTERNAL_PARAMETER_TAG(long, 1);
CROW_INTERNAL_PARAMETER_TAG(long long, 1);
CROW_INTERNAL_PARAMETER_TAG(unsigned int, 2);
CROW_INTERNAL_PARAMETER_TAG(unsigned char, 2);
CROW_INTERNAL_PARAMETER_TAG(unsigned short, 2);
CROW_INTERNAL_PARAMETER_TAG(unsigned long, 2);
CROW_INTERNAL_PARAMETER_TAG(unsigned long long, 2);
CROW_INTERNAL_PARAMETER_TAG(double, 3);
CROW_INTERNAL_PARAMETER_TAG(std::string, 4);
#undef CROW_INTERNAL_PARAMETER_TAG
template<typename... Args>
struct compute_parameter_tag_from_args_list;
template<>
struct compute_parameter_tag_from_args_list<>
{
static const int value = 0;
};
template<typename Arg, typename... Args>
struct compute_parameter_tag_from_args_list<Arg, Args...>
{
static const int sub_value =
compute_parameter_tag_from_args_list<Args...>::value;
static const int value =
parameter_tag<typename std::decay<Arg>::type>::value ? sub_value * 6 + parameter_tag<typename std::decay<Arg>::type>::value : sub_value;
};
static inline bool is_parameter_tag_compatible(uint64_t a, uint64_t b)
{
if (a == 0)
return b == 0;
if (b == 0)
return a == 0;
int sa = a % 6;
int sb = a % 6;
if (sa == 5) sa = 4;
if (sb == 5) sb = 4;
if (sa != sb)
return false;
return is_parameter_tag_compatible(a / 6, b / 6);
}
static inline unsigned find_closing_tag_runtime(const char* s, unsigned p)
{
return s[p] == 0 ? throw std::runtime_error("unmatched tag <") :
s[p] == '>' ? p :
find_closing_tag_runtime(s, p + 1);
}
static inline uint64_t get_parameter_tag_runtime(const char* s, unsigned p = 0)
{
return s[p] == 0 ? 0 :
s[p] == '<' ? (
std::strncmp(s + p, "<int>", 5) == 0 ? get_parameter_tag_runtime(s, find_closing_tag_runtime(s, p)) * 6 + 1 :
std::strncmp(s + p, "<uint>", 6) == 0 ? get_parameter_tag_runtime(s, find_closing_tag_runtime(s, p)) * 6 + 2 :
(std::strncmp(s + p, "<float>", 7) == 0 ||
std::strncmp(s + p, "<double>", 8) == 0) ?
get_parameter_tag_runtime(s, find_closing_tag_runtime(s, p)) * 6 + 3 :
(std::strncmp(s + p, "<str>", 5) == 0 ||
std::strncmp(s + p, "<string>", 8) == 0) ?
get_parameter_tag_runtime(s, find_closing_tag_runtime(s, p)) * 6 + 4 :
std::strncmp(s + p, "<path>", 6) == 0 ? get_parameter_tag_runtime(s, find_closing_tag_runtime(s, p)) * 6 + 5 :
throw std::runtime_error("invalid parameter type")) :
get_parameter_tag_runtime(s, p + 1);
}
#ifndef CROW_MSVC_WORKAROUND
constexpr uint64_t get_parameter_tag(const_str s, unsigned p = 0)
{
return p == s.size() ? 0 :
s[p] == '<' ? (
is_int(s, p) ? get_parameter_tag(s, find_closing_tag(s, p)) * 6 + 1 :
is_uint(s, p) ? get_parameter_tag(s, find_closing_tag(s, p)) * 6 + 2 :
is_float(s, p) ? get_parameter_tag(s, find_closing_tag(s, p)) * 6 + 3 :
is_str(s, p) ? get_parameter_tag(s, find_closing_tag(s, p)) * 6 + 4 :
is_path(s, p) ? get_parameter_tag(s, find_closing_tag(s, p)) * 6 + 5 :
throw std::runtime_error("invalid parameter type")) :
get_parameter_tag(s, p + 1);
}
#endif
template<typename... T>
struct S
{
template<typename U>
using push = S<U, T...>;
template<typename U>
using push_back = S<T..., U>;
template<template<typename... Args> class U>
using rebind = U<T...>;
};
// Check whether the template function can be called with specific arguments
template<typename F, typename Set>
struct CallHelper;
template<typename F, typename... Args>
struct CallHelper<F, S<Args...>>
{
template<typename F1, typename... Args1, typename = decltype(std::declval<F1>()(std::declval<Args1>()...))>
static char __test(int);
template<typename...>
static int __test(...);
static constexpr bool value = sizeof(__test<F, Args...>(0)) == sizeof(char);
};
// Check Tuple contains type T
template<typename T, typename Tuple>
struct has_type;
template<typename T>
struct has_type<T, std::tuple<>> : std::false_type
{};
template<typename T, typename U, typename... Ts>
struct has_type<T, std::tuple<U, Ts...>> : has_type<T, std::tuple<Ts...>>
{};
template<typename T, typename... Ts>
struct has_type<T, std::tuple<T, Ts...>> : std::true_type
{};
// Find index of type in tuple
template<class T, class Tuple>
struct tuple_index;
template<class T, class... Types>
struct tuple_index<T, std::tuple<T, Types...>>
{
static const int value = 0;
};
template<class T, class U, class... Types>
struct tuple_index<T, std::tuple<U, Types...>>
{
static const int value = 1 + tuple_index<T, std::tuple<Types...>>::value;
};
// Extract element from forward tuple or get default
#ifdef CROW_CAN_USE_CPP14
template<typename T, typename Tup>
typename std::enable_if<has_type<T&, Tup>::value, typename std::decay<T>::type&&>::type
tuple_extract(Tup& tup)
{
return std::move(std::get<T&>(tup));
}
#else
template<typename T, typename Tup>
typename std::enable_if<has_type<T&, Tup>::value, T&&>::type
tuple_extract(Tup& tup)
{
return std::move(std::get<tuple_index<T&, Tup>::value>(tup));
}
#endif
template<typename T, typename Tup>
typename std::enable_if<!has_type<T&, Tup>::value, T>::type
tuple_extract(Tup&)
{
return T{};
}
// Kind of fold expressions in C++11
template<bool...>
struct bool_pack;
template<bool... bs>
using all_true = std::is_same<bool_pack<bs..., true>, bool_pack<true, bs...>>;
template<int N>
struct single_tag_to_type
{};
template<>
struct single_tag_to_type<1>
{
using type = int64_t;
};
template<>
struct single_tag_to_type<2>
{
using type = uint64_t;
};
template<>
struct single_tag_to_type<3>
{
using type = double;
};
template<>
struct single_tag_to_type<4>
{
using type = std::string;
};
template<>
struct single_tag_to_type<5>
{
using type = std::string;
};
template<uint64_t Tag>
struct arguments
{
using subarguments = typename arguments<Tag / 6>::type;
using type =
typename subarguments::template push<typename single_tag_to_type<Tag % 6>::type>;
};
template<>
struct arguments<0>
{
using type = S<>;
};
template<typename... T>
struct last_element_type
{
using type = typename std::tuple_element<sizeof...(T) - 1, std::tuple<T...>>::type;
};
template<>
struct last_element_type<>
{};
// from http://stackoverflow.com/questions/13072359/c11-compile-time-array-with-logarithmic-evaluation-depth
template<class T>
using Invoke = typename T::type;
template<unsigned...>
struct seq
{
using type = seq;
};
template<class S1, class S2>
struct concat;
template<unsigned... I1, unsigned... I2>
struct concat<seq<I1...>, seq<I2...>> : seq<I1..., (sizeof...(I1) + I2)...>
{};
template<class S1, class S2>
using Concat = Invoke<concat<S1, S2>>;
template<unsigned N>
struct gen_seq;
template<unsigned N>
using GenSeq = Invoke<gen_seq<N>>;
template<unsigned N>
struct gen_seq : Concat<GenSeq<N / 2>, GenSeq<N - N / 2>>
{};
template<>
struct gen_seq<0> : seq<>
{};
template<>
struct gen_seq<1> : seq<0>
{};
template<typename Seq, typename Tuple>
struct pop_back_helper;
template<unsigned... N, typename Tuple>
struct pop_back_helper<seq<N...>, Tuple>
{
template<template<typename... Args> class U>
using rebind = U<typename std::tuple_element<N, Tuple>::type...>;
};
template<typename... T>
struct pop_back //: public pop_back_helper<typename gen_seq<sizeof...(T)-1>::type, std::tuple<T...>>
{
template<template<typename... Args> class U>
using rebind = typename pop_back_helper<typename gen_seq<sizeof...(T) - 1>::type, std::tuple<T...>>::template rebind<U>;
};
template<>
struct pop_back<>
{
template<template<typename... Args> class U>
using rebind = U<>;
};
// from http://stackoverflow.com/questions/2118541/check-if-c0x-parameter-pack-contains-a-type
template<typename Tp, typename... List>
struct contains : std::true_type
{};
template<typename Tp, typename Head, typename... Rest>
struct contains<Tp, Head, Rest...> : std::conditional<std::is_same<Tp, Head>::value, std::true_type, contains<Tp, Rest...>>::type
{};
template<typename Tp>
struct contains<Tp> : std::false_type
{};
template<typename T>
struct empty_context
{};
template<typename T>
struct promote
{
using type = T;
};
#define CROW_INTERNAL_PROMOTE_TYPE(t1, t2) \
template<> \
struct promote<t1> \
{ \
using type = t2; \
}
CROW_INTERNAL_PROMOTE_TYPE(char, int64_t);
CROW_INTERNAL_PROMOTE_TYPE(short, int64_t);
CROW_INTERNAL_PROMOTE_TYPE(int, int64_t);
CROW_INTERNAL_PROMOTE_TYPE(long, int64_t);
CROW_INTERNAL_PROMOTE_TYPE(long long, int64_t);
CROW_INTERNAL_PROMOTE_TYPE(unsigned char, uint64_t);
CROW_INTERNAL_PROMOTE_TYPE(unsigned short, uint64_t);
CROW_INTERNAL_PROMOTE_TYPE(unsigned int, uint64_t);
CROW_INTERNAL_PROMOTE_TYPE(unsigned long, uint64_t);
CROW_INTERNAL_PROMOTE_TYPE(unsigned long long, uint64_t);
CROW_INTERNAL_PROMOTE_TYPE(float, double);
#undef CROW_INTERNAL_PROMOTE_TYPE
template<typename T>
using promote_t = typename promote<T>::type;
} // namespace black_magic
namespace detail
{
template<class T, std::size_t N, class... Args>
struct get_index_of_element_from_tuple_by_type_impl
{
static constexpr auto value = N;
};
template<class T, std::size_t N, class... Args>
struct get_index_of_element_from_tuple_by_type_impl<T, N, T, Args...>
{
static constexpr auto value = N;
};
template<class T, std::size_t N, class U, class... Args>
struct get_index_of_element_from_tuple_by_type_impl<T, N, U, Args...>
{
static constexpr auto value = get_index_of_element_from_tuple_by_type_impl<T, N + 1, Args...>::value;
};
} // namespace detail
namespace utility
{
template<class T, class... Args>
T& get_element_by_type(std::tuple<Args...>& t)
{
return std::get<detail::get_index_of_element_from_tuple_by_type_impl<T, 0, Args...>::value>(t);
}
template<typename T>
struct function_traits;
#ifndef CROW_MSVC_WORKAROUND
template<typename T>
struct function_traits : public function_traits<decltype(&T::operator())>
{
using parent_t = function_traits<decltype(&T::operator())>;
static const size_t arity = parent_t::arity;
using result_type = typename parent_t::result_type;
template<size_t i>
using arg = typename parent_t::template arg<i>;
};
#endif
template<typename ClassType, typename R, typename... Args>
struct function_traits<R (ClassType::*)(Args...) const>
{
static const size_t arity = sizeof...(Args);
typedef R result_type;
template<size_t i>
using arg = typename std::tuple_element<i, std::tuple<Args...>>::type;
};
template<typename ClassType, typename R, typename... Args>
struct function_traits<R (ClassType::*)(Args...)>
{
static const size_t arity = sizeof...(Args);
typedef R result_type;
template<size_t i>
using arg = typename std::tuple_element<i, std::tuple<Args...>>::type;
};
template<typename R, typename... Args>
struct function_traits<std::function<R(Args...)>>
{
static const size_t arity = sizeof...(Args);
typedef R result_type;
template<size_t i>
using arg = typename std::tuple_element<i, std::tuple<Args...>>::type;
};
/// @endcond
inline static std::string base64encode(const unsigned char* data, size_t size, const char* key = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/")
{
std::string ret;
ret.resize((size + 2) / 3 * 4);
auto it = ret.begin();
while (size >= 3)
{
*it++ = key[(static_cast<unsigned char>(*data) & 0xFC) >> 2];
unsigned char h = (static_cast<unsigned char>(*data++) & 0x03) << 4;
*it++ = key[h | ((static_cast<unsigned char>(*data) & 0xF0) >> 4)];
h = (static_cast<unsigned char>(*data++) & 0x0F) << 2;
*it++ = key[h | ((static_cast<unsigned char>(*data) & 0xC0) >> 6)];
*it++ = key[static_cast<unsigned char>(*data++) & 0x3F];
size -= 3;
}
if (size == 1)
{
*it++ = key[(static_cast<unsigned char>(*data) & 0xFC) >> 2];
unsigned char h = (static_cast<unsigned char>(*data++) & 0x03) << 4;
*it++ = key[h];
*it++ = '=';
*it++ = '=';
}
else if (size == 2)
{
*it++ = key[(static_cast<unsigned char>(*data) & 0xFC) >> 2];
unsigned char h = (static_cast<unsigned char>(*data++) & 0x03) << 4;
*it++ = key[h | ((static_cast<unsigned char>(*data) & 0xF0) >> 4)];
h = (static_cast<unsigned char>(*data++) & 0x0F) << 2;
*it++ = key[h];
*it++ = '=';
}
return ret;
}
inline static std::string base64encode(std::string data, size_t size, const char* key = "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789+/")
{
return base64encode((const unsigned char*)data.c_str(), size, key);
}
inline static std::string base64encode_urlsafe(const unsigned char* data, size_t size)
{
return base64encode(data, size, "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_");
}
inline static std::string base64encode_urlsafe(std::string data, size_t size)
{
return base64encode((const unsigned char*)data.c_str(), size, "ABCDEFGHIJKLMNOPQRSTUVWXYZabcdefghijklmnopqrstuvwxyz0123456789-_");
}
inline static std::string base64decode(const char* data, size_t size)
{
// We accept both regular and url encoding here, as there does not seem to be any downside to that.
// If we want to distinguish that we should use +/ for non-url and -_ for url.
// Mapping logic from characters to [0-63]
auto key = [](char c) -> unsigned char {
if ((c >= 'A') && (c <= 'Z')) return c - 'A';
if ((c >= 'a') && (c <= 'z')) return c - 'a' + 26;
if ((c >= '0') && (c <= '9')) return c - '0' + 52;
if ((c == '+') || (c == '-')) return 62;
if ((c == '/') || (c == '_')) return 63;
return 0;
};
// Not padded
if (size % 4 == 2) // missing last 2 characters
size = (size / 4 * 3) + 1; // Not subtracting extra characters because they're truncated in int division
else if (size % 4 == 3) // missing last character
size = (size / 4 * 3) + 2; // Not subtracting extra characters because they're truncated in int division
// Padded
else if (data[size - 2] == '=') // padded with '=='
size = (size / 4 * 3) - 2; // == padding means the last block only has 1 character instead of 3, hence the '-2'
else if (data[size - 1] == '=') // padded with '='
size = (size / 4 * 3) - 1; // = padding means the last block only has 2 character instead of 3, hence the '-1'
// Padding not needed
else
size = size / 4 * 3;
std::string ret;
ret.resize(size);
auto it = ret.begin();
// These will be used to decode 1 character at a time
unsigned char odd; // char1 and char3
unsigned char even; // char2 and char4
// Take 4 character blocks to turn into 3
while (size >= 3)
{
// dec_char1 = (char1 shifted 2 bits to the left) OR ((char2 AND 00110000) shifted 4 bits to the right))
odd = key(*data++);
even = key(*data++);
*it++ = (odd << 2) | ((even & 0x30) >> 4);
// dec_char2 = ((char2 AND 00001111) shifted 4 bits left) OR ((char3 AND 00111100) shifted 2 bits right))
odd = key(*data++);
*it++ = ((even & 0x0F) << 4) | ((odd & 0x3C) >> 2);
// dec_char3 = ((char3 AND 00000011) shifted 6 bits left) OR (char4)
even = key(*data++);
*it++ = ((odd & 0x03) << 6) | (even);
size -= 3;
}
if (size == 2)
{
// d_char1 = (char1 shifted 2 bits to the left) OR ((char2 AND 00110000) shifted 4 bits to the right))
odd = key(*data++);
even = key(*data++);
*it++ = (odd << 2) | ((even & 0x30) >> 4);
// d_char2 = ((char2 AND 00001111) shifted 4 bits left) OR ((char3 AND 00111100) shifted 2 bits right))
odd = key(*data++);
*it++ = ((even & 0x0F) << 4) | ((odd & 0x3C) >> 2);
}
else if (size == 1)
{
// d_char1 = (char1 shifted 2 bits to the left) OR ((char2 AND 00110000) shifted 4 bits to the right))
odd = key(*data++);
even = key(*data++);
*it++ = (odd << 2) | ((even & 0x30) >> 4);
}
return ret;
}
inline static std::string base64decode(const std::string& data, size_t size)
{
return base64decode(data.data(), size);
}
inline static std::string base64decode(const std::string& data)
{
return base64decode(data.data(), data.length());
}
inline static std::string normalize_path(const std::string& directoryPath)
{
std::string normalizedPath = directoryPath;
std::replace(normalizedPath.begin(), normalizedPath.end(), '\\', '/');
if (!normalizedPath.empty() && normalizedPath.back() != '/')
normalizedPath += '/';
return normalizedPath;
}
inline static void sanitize_filename(std::string& data, char replacement = '_')
{
if (data.length() > 255)
data.resize(255);
static const auto toUpper = [](char c) {
return ((c >= 'a') && (c <= 'z')) ? (c - ('a' - 'A')) : c;
};
// Check for special device names. The Windows behavior is really odd here, it will consider both AUX and AUX.txt
// a special device. Thus we search for the string (case-insensitive), and then check if the string ends or if
// is has a dangerous follow up character (.:\/)
auto sanitizeSpecialFile = [](std::string& source, unsigned ofs, const char* pattern, bool includeNumber, char replacement) {
unsigned i = ofs;
size_t len = source.length();
const char* p = pattern;
while (*p)
{
if (i >= len) return;
if (toUpper(source[i]) != *p) return;
++i;
++p;
}
if (includeNumber)
{
if ((i >= len) || (source[i] < '1') || (source[i] > '9')) return;
++i;
}
if ((i >= len) || (source[i] == '.') || (source[i] == ':') || (source[i] == '/') || (source[i] == '\\'))
{
source.erase(ofs + 1, (i - ofs) - 1);
source[ofs] = replacement;
}
};
bool checkForSpecialEntries = true;
for (unsigned i = 0; i < data.length(); ++i)
{
// Recognize directory traversals and the special devices CON/PRN/AUX/NULL/COM[1-]/LPT[1-9]
if (checkForSpecialEntries)
{
checkForSpecialEntries = false;
switch (toUpper(data[i]))
{
case 'A':
sanitizeSpecialFile(data, i, "AUX", false, replacement);
break;
case 'C':
sanitizeSpecialFile(data, i, "CON", false, replacement);
sanitizeSpecialFile(data, i, "COM", true, replacement);
break;
case 'L':
sanitizeSpecialFile(data, i, "LPT", true, replacement);
break;
case 'N':
sanitizeSpecialFile(data, i, "NUL", false, replacement);
break;
case 'P':
sanitizeSpecialFile(data, i, "PRN", false, replacement);
break;
case '.':
sanitizeSpecialFile(data, i, "..", false, replacement);
break;
}
}
// Sanitize individual characters
unsigned char c = data[i];
if ((c < ' ') || ((c >= 0x80) && (c <= 0x9F)) || (c == '?') || (c == '<') || (c == '>') || (c == ':') || (c == '*') || (c == '|') || (c == '\"'))
{
data[i] = replacement;
}
else if ((c == '/') || (c == '\\'))
{
if (CROW_UNLIKELY(i == 0)) //Prevent Unix Absolute Paths (Windows Absolute Paths are prevented with `(c == ':')`)
{
data[i] = replacement;
}
else
{
checkForSpecialEntries = true;
}
}
}
}
inline static std::string random_alphanum(std::size_t size)
{
static const char alphabet[] = "0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ";
std::random_device dev;
std::mt19937 rng(dev());
std::uniform_int_distribution<std::mt19937::result_type> dist(0, sizeof(alphabet) - 2);
std::string out;
out.reserve(size);
for (std::size_t i = 0; i < size; i++)
out.push_back(alphabet[dist(rng)]);
return out;
}
inline static std::string join_path(std::string path, const std::string& fname)
{
#if defined(CROW_CAN_USE_CPP17) && !defined(CROW_FILESYSTEM_IS_EXPERIMENTAL)
return (std::filesystem::path(path) / fname).string();
#else
if (!(path.back() == '/' || path.back() == '\\'))
path += '/';
path += fname;
return path;
#endif
}
/**
* @brief Checks two string for equality.
* Always returns false if strings differ in size.
* Defaults to case-insensitive comparison.
*/
inline static bool string_equals(const std::string& l, const std::string& r, bool case_sensitive = false)
{
if (l.length() != r.length())
return false;
for (size_t i = 0; i < l.length(); i++)
{
if (case_sensitive)
{
if (l[i] != r[i])
return false;
}
else
{
if (std::toupper(l[i]) != std::toupper(r[i]))
return false;
}
}
return true;
}
template<typename T, typename U>
inline static T lexical_cast(const U& v)
{
std::stringstream stream;
T res;
stream << v;
stream >> res;
return res;
}
template<typename T>
inline static T lexical_cast(const char* v, size_t count)
{
std::stringstream stream;
T res;
stream.write(v, count);
stream >> res;
return res;
}
/// Return a copy of the given string with its
/// leading and trailing whitespaces removed.
inline static std::string trim(const std::string& v)
{
if (v.empty())
return "";
size_t begin = 0, end = v.length();
size_t i;
for (i = 0; i < v.length(); i++)
{
if (!std::isspace(v[i]))
{
begin = i;
break;
}
}
if (i == v.length())
return "";
for (i = v.length(); i > 0; i--)
{
if (!std::isspace(v[i - 1]))
{
end = i;
break;
}
}
return v.substr(begin, end - begin);
}
} // namespace utility
} // namespace crow
crow
The main namespace of the library. In this namespace is defined the most important classes and functi...