StrUtils.hpp

#pragma once
#define PCL_STRUTILS

#include<string>
#include<vector>
#include<set>
#include<functional>

namespace pc{
/**
 * @brief Utilitys for string processing
 */
namespace strutil{
using std::string;
/// @brief Function to decide whether a char is something
typedef std::function<bool(char)> CharType;
/// @brief Pre-defined delimiter functions
namespace Delimiters{
	const CharType Word=	[](char a){return bool(isspace(a));};
	const CharType Name=	[](char a){return !isalnum(a)&&a!='_';};
	const CharType Line=	[](char a){return a=='\r'||a=='\n';};
	const CharType Int=	[](char a){return bool(isspace(a));};
	const CharType Double=	[](char a){return bool(isspace(a));};
	CharType List(std::string_view str){
		return [str](char a){return str.contains(a);};
	}
}
/// @brief Remove leading and trailing whitespace from a string
string Trim(string a)
{
	int j=a.length(),i=0;
	while(i<j&&isspace(a[i]))	i++;
	while(j>i&&isspace(a[j-1]))	j--;
	return a.substr(i,j-i);
}
/// @brief Remove leading and trailing whitespace from a string
string Trim(string a,bool (*isSpace)(char a))
{
	int j=a.length(),i=0;
	while(i<j&&isSpace(a[i]))	i++;
	while(j>i&&isSpace(a[j-1]))	j--;
	return a.substr(i,j-i);
}
/**
 * @brief Get a token breaking with delimiter from string
 * @param isDelimiter Decide whether the char is a delimiter
 * @param modify Whether delete the word form origin string, default `true`
 * @return The gotten token
 */
string ExtractToken(string& a,CharType isDelimiter,bool modify=true)
{
	string ans;
	int i=0,len=a.length();
	while(i<len&&isDelimiter(a[i]))	i++;
	for(;i<len;i++)
		if(isDelimiter(a[i]))	break;
		else	ans+=a[i];
	if(!modify)	return ans;
	a=a.substr(i);
	return ans;
}
inline string ExtractToken(string& a,std::string_view delimiters,bool modify=true){
	return ExtractToken(a,[delimiters](char a){
		return delimiters.contains(a);
	},modify);
}
/// @brief Break by space 
inline string ExtractWord(string& a,bool modify=true){
	return ExtractToken(a,Delimiters::Word,modify);
}
/// @brief Name contains alphabets, numbers and underlines(`_`) 
inline string ExtractName(string& a,bool modify=true){
	return ExtractToken(a,Delimiters::Name,modify);
}
/// @brief Break by enter
inline string ExtractLine(string& a,bool modify=true){
	return ExtractToken(a,Delimiters::Line,modify);
}
/**
 * @warning Inputing `1.23` will get `1` and `.23`!
 * Consider using `ExtractDouble()` for that.
 */
inline int ExtractInt(string& a,bool modify=true){
	string num=ExtractToken(a,Delimiters::Int,modify);
	return std::stoi(num);
}
/// @brief Works literally 
inline double ExtractDouble(string& a,bool modify=true){
	string num=ExtractToken(a,Delimiters::Double,modify);
	return std::stod(num);
}
/// @brief Check if a string is empty (contains only whitespace)
inline bool isEmpty(string a)
{
	for(char i:a)
		if(!isspace(i))
			return false;
	return true;
}

/**
 * @brief Split string with delimiters
 * @param isDelimiter Decide whether the char is a delimiter
 */
std::vector<string> Split(std::string_view str,CharType isDelimiter)
{
	std::vector<string> ans;
	string one;
	for(char i:str)
		if(isDelimiter(i))
			if(!one.empty())
				ans.push_back(one),
				one="";
			else;
		else
			one.push_back(i);
	if(!one.empty())
		ans.push_back(one);
	return ans;
}
/// @brief Split string with delimiters
std::vector<std::string> Split(std::string_view str, std::string_view delimiters){
	return Split(str,Delimiters::List(delimiters));
}
/// @brief Split string with space
std::vector<std::string> Split(std::string_view str)
	{return Split(str,Delimiters::Word);}
string ToLowercase(string a){
	for(char &i:a)
		i=tolower(i);
	return a;
}
string ToUppercase(string a){
	for(char &i:a)
		i=toupper(i);
	return a;
}
string Capitalize(string a){
	if(a.length()>0)
		a[0]=toupper(a[0]);
	return a;
}
/**
 * @brief Escape string so that it is json valid
 * @note For example, 
 * ```text
 * Hello world\tPClib\n \\ \u17
 * ```
 * returns
 * ```text
 * "Hello world\\tPClib\\n \\\\ \\u17"
 * ```
 */
std::string Escape(const std::string_view& str)
{
	std::string ans="\"";
	ans.reserve(str.size()+4);
	for(unsigned char c:str)
		switch(c){
			case '"':	ans += "\\\"";	break;
			case '\\':	ans += "\\\\";	break;
			case '\n':	ans += "\\n";	break;
			case '\r':	ans += "\\r";	break;
			case '\t':	ans += "\\t";	break;
			case '\b':	ans += "\\b";	break;
			case '\f':	ans += "\\f";	break;
			default:
				if(c<0x20)
					ans+=std::format("\\u{:04x}",static_cast<int>(c));
				else	ans+=static_cast<char>(c);
		};
	ans+="\"";
	return ans;
}

} // namespace su
namespace su=strutil;
} // namespace pc