feat: finish string helper except Split()

- add string lower upper function in string helper.
- add join function in string helper.
- add split function in string helper but implementation is not perfect and should be imporved in future.
This commit is contained in:
yyc12345 2024-05-21 10:24:05 +08:00
parent 6ebb457bd1
commit 9c943705de
3 changed files with 186 additions and 4 deletions

View File

@ -1,4 +1,5 @@
#include "StringHelper.hpp"
#include <algorithm>
namespace YYCC::StringHelper {
@ -32,7 +33,7 @@ namespace YYCC::StringHelper {
strl.resize(count);
int write_result = std::vsnprintf(strl.data(), strl.size() + 1, format, args2);
va_end(args2);
if (write_result < 0 || write_result > count) {
// invalid write result in vsnprintf.
return false;
@ -41,10 +42,10 @@ namespace YYCC::StringHelper {
return true;
}
std::string Printf(const char* format, ...) {
std::string ret;
va_list argptr;
va_start(argptr, format);
VPrintf(ret, format, argptr);
@ -64,4 +65,124 @@ namespace YYCC::StringHelper {
return ret;
}
std::string Join(JoinDataProvider fct_data, const char* decilmer) {
std::string ret;
bool is_first = true;
const char* element;
// fetch element
while ((element = fct_data()) != nullptr) {
// insert decilmer
if (is_first) is_first = false;
else {
// only insert non-nullptr decilmer.
if (decilmer != nullptr)
ret.append(decilmer);
}
// insert element
ret.append(element);
}
return ret;
}
std::string Join(const std::vector<std::string>& data, const char* decilmer, bool reversed) {
if (reversed) {
auto iter = data.crbegin();
auto stop = data.crend();
return Join([&iter, &stop]() -> const char* {
// if we reach tail, return nullptr
if (iter == stop) return nullptr;
// otherwise fetch data, inc iterator and return.
const char* ret = iter->c_str();
++iter;
return ret;
}, decilmer);
} else {
auto iter = data.cbegin();
auto stop = data.cend();
return Join([&iter, &stop]() -> const char* {
// if we reach tail, return nullptr
if (iter == stop) return nullptr;
// otherwise fetch data, inc iterator and return.
const char* ret = iter->c_str();
++iter;
return ret;
}, decilmer);
}
}
template<bool bIsToLower>
void GeneralStringLowerUpper(std::string& strl) {
// https://en.cppreference.com/w/cpp/algorithm/transform
// https://en.cppreference.com/w/cpp/string/byte/tolower
std::transform(
strl.cbegin(), strl.cend(), strl.begin(),
[](unsigned char c) -> char {
if constexpr (bIsToLower) return std::tolower(c);
else return std::toupper(c);
}
);
}
std::string Lower(const char* strl) {
std::string ret;
if (strl == nullptr) return ret;
else ret = strl;
Lower(ret);
return ret;
}
void Lower(std::string& strl) {
GeneralStringLowerUpper<true>(strl);
}
std::string Upper(const char* strl) {
// same as Lower, just replace char transform function.
std::string ret;
if (strl == nullptr) return ret;
else ret = strl;
Upper(ret);
return ret;
}
void Upper(std::string& strl) {
GeneralStringLowerUpper<false>(strl);
}
std::vector<std::string> Split(const char* _strl, const char* _decilmer) {
std::vector<std::string> elems;
// check whether string and decilmer are nullptr
std::string strl, decilmer;
if (_strl == nullptr || _decilmer == nullptr)
return elems;
else {
strl = _strl;
decilmer = _decilmer;
}
// if no decilmer, return the whole string as the only one element of result.
if (decilmer.empty()) {
elems.push_back(strl);
return elems;
}
// start spliting
std::size_t previous = 0;
std::size_t current = strl.find(decilmer.c_str());
while (current != std::string::npos) {
if (current >= previous) {
elems.push_back(strl.substr(previous, current - previous));
}
previous = current + decilmer.size();
current = strl.find(decilmer, previous);
}
if (previous != strl.size()) {
elems.push_back(strl.substr(previous));
}
return elems;
}
}

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@ -1,6 +1,8 @@
#pragma once
#include <string>
#include <cstdarg>
#include <functional>
#include <vector>
namespace YYCC::StringHelper {
@ -10,6 +12,53 @@ namespace YYCC::StringHelper {
std::string Printf(const char* format, ...);
std::string VPrintf(const char* format, va_list argptr);
//std::string Join(const char* decilmer);
/**
* @brief The data provider of general Join function.
* This function pointer return non-null string pointer to represent a element of joined series.
* otherwise return nullptr to terminate the joining process.
*/
using JoinDataProvider = std::function<const char*()>;
/**
* @brief General Join function.
* @details This function use function pointer as a general data provider interface,
* so this function suit for all types container, the user only need write a little bit adaption code.
* @param fct_data[in] The function pointer to data provider.
* @param decilmer[in] The decilmer.
* @return A std::string instance which containing the join result.
*/
std::string Join(JoinDataProvider fct_data, const char* decilmer);
/**
* @brief Specialized Join function for common used container.
* @param data
* @param decilmer
* @param reversed
* @return
*/
std::string Join(const std::vector<std::string>& data, const char* decilmer, bool reversed = false);
/**
* @brief Transform string to lower.
* @param strl
* @return
*/
std::string Lower(const char* strl);
void Lower(std::string& strl);
/**
* @brief Transform string to upper.
* @param strl
* @return
*/
std::string Upper(const char* strl);
void Upper(std::string& strl);
/**
* @brief General Split function.
* @param _strl
* @param _decilmer
* @return
* @remarks This function may be low performance because it just a homebrew Split functon.
* It can works in most toy cases but not suit for high performance scenario.
* Also, this function will produce a copy of original string because it is not zero copy.
*/
std::vector<std::string> Split(const char* _strl, const char* _decilmer);
}

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@ -15,6 +15,18 @@ namespace Testbench {
YYCC::StringHelper::Printf(u8"Translation: %s == %s\n", u8"Hello World", u8"你好世界").c_str(),
stdout
);
std::string test_string(u8"UPPER -> lower\n");
YYCC::TerminalHelper::FPuts(test_string.c_str(), stdout);
YYCC::TerminalHelper::FPuts(YYCC::StringHelper::Lower(test_string.c_str()).c_str(), stdout);
YYCC::TerminalHelper::FPuts(YYCC::StringHelper::Upper(test_string.c_str()).c_str(), stdout);
std::vector<std::string> test_container {
"test1", "test2", "test3", "test4"
};
YYCC::TerminalHelper::FPuts(YYCC::StringHelper::Join(test_container, ", ").c_str(), stdout);
std::string test_split(", 1, 3, 5, 7, 9, ");
YYCC::TerminalHelper::FPuts(YYCC::StringHelper::Join(YYCC::StringHelper::Split(test_split.c_str(), ", "), " -> ").c_str(), stdout);
}
}