string lite: string algorithms for C++11 and later

Note: this library was previously named string-bare, the original string-lite has been renamed to string-non-lite.

Another attempt at a hopefully generally useful C++ string algorithm library.

I'm still pondering to add functions that take a regular expression, as std::regexand as string (using *_re() function names), and the API to use for that.

For now, have a look at section Documentation of string lite and section string-lite test specification for the functions envisioned / implemented. The in-place modification class of functions is decidedly absent.

Contents

• Example usage
• In a nutshell
• License
• Dependencies
• Installation and use
• Synopsis
• Notes and references
• Appendix

Example usage

// Use nonstd::string's split():

#include "nonstd/string.hpp"
#include <iostream>
#include <sstream>
#include <string>
#include <vector>

template< typename T >
std::string contents(std::vector<T> const & coll)
{
    // using nonstd::to_string() for nonstd::std17::string_view:
    using nonstd::to_string;

    std::stringstream os;
    for ( auto const & elem : coll )
        os << "'" << to_string(elem) << "', ";
    return os.str();
}

template< typename T >
std::ostream & operator<<(std::ostream & os, std::vector<T> const & coll )
{
    return os << "[" << contents(coll) << "]";
}

int main()
{
    std::cout << nonstd::string::split("Hello, world", ", ");
}

Compile and run

prompt> g++ -std=c++11 -Wall -I../include -o 01-basic.exe 01-basic.cpp && 01-basic.exe
['Hello', 'world', ]

In a nutshell

string lite is a single-file header-only library to provide various string algorithms. Firstly meant to get you up and running easily, not necessarily to provide everything that might be useful and in the most efficient manner.

Creating string lite I've had a look at the C++ standard, Boost, Facebook Folly, the Python standard library, the proposal for std::split() and several algorithms I created over time.

In general, functions take string_views and thereby char const *, std::string and std::string_view (note 1) as arguments and produce (return) a bool, size_t, std::string or a collection of string_views.

Note 1: to support use of string_views with C++ versions earlier than C++17, string_views may be accessed as nonstd::string::std17::string_view, supplying a local string_view class or std::string_view if present.

Features and properties of string lite are ease of installation (single header), freedom of dependencies other than the standard library.

License

string lite is distributed under the Boost Software License.

Dependencies

string lite has no other dependencies than the C++ standard library.

Installation and use

string lite is a single-file header-only library. Put string.hpp in the include folder directly into the project source tree or somewhere reachable from your project.

Synopsis

Contents
Documentation of string lite
Configuration

Documentation of string lite

The following table presents types, values and simplified, short prototypes of the functions in string-lite's nonstd namespace.

Kind	Type or function	Notes
Type	[string::]std17::basic_string_view	std::basic_string_view for C++17 and later, polyfill otherwise
	[string::]std17::string_view	character variations as requested, see section Configuration
	[string::]std17::wstring_view;
	[string::]std17::u8string_view;
	[string::]std17::u16string_view;
	[string::]std17::u32string_view;
Value	size_t string::npos	not-found position value, in nonstd::string namespace
Utility	string to_string(string_view sv)	string from local or C++17 std string_view
Comparison	int compare(string_view lhs, string_view rhs)	negative, zero or positive for lsh is less than, equal to or greater than rhs
	bool operator==(string_view lhs, string_view rhs)	true if lhs string is equal to rhs string
	bool operator!=(string_view lhs, string_view rhs)	true if lhs string is not equal to rhs string
	bool operator<(string_view lhs, string_view rhs)	true if lhs string is less than rhs string
	bool operator<=(string_view lhs, string_view rhs)	true if lhs string is less than or equal to rhs string
	bool operator>=(string_view lhs, string_view rhs)	true if lhs string is greater than or equal to rhs string
	bool operator>(string_view lhs, string_view rhs)	true if lhs string is greater than or equal to rhs string
Observer	size_t length(string_view sv)	length of string
	size_t size(string_view sv)	length of string
	bool is_empty(string_view sv)	true if string is empty
contains	bool contains(string_view sv, string_view what)	true if string contains given string
	bool contains_all_of(string_view sv, string_view set)	true if string contains all characters of set
	bool contains_any_of(string_view sv, string_view set)	true if string contains any character of set
	bool contains_none_of(string_view sv, string_view set)	true if string contains no character of set
starts_with	bool starts_with(string_view sv, string_view what)	true if string starts with given string
	bool starts_with_all_of(string_view sv, string_view set)	true if string starts with all characters of set
	bool starts_with_any_of(string_view sv, string_view set)	true if string starts with any character of set
	bool starts_with_none_of(string_view sv, string_view set)	true if string starts with no character of set
ends_with	bool ends_with(string_view sv, string_view what)	true if string ends with given string
	bool ends_with_all_of(string_view sv, string_view set)	true if string ends with all characters of set
	bool ends_with_any_of(string_view sv, string_view set)	true if string ends with any character of set
	bool ends_with_none_of(string_view sv, string_view set)	true if string ends with no character of set
Searching	size_t find_first(string_view sv, string_view what)	position of first occurrence of given string, or npos
	size_t find_first_of(string_view sv, string_view set)	position of first occurrence of character in set, or npos
	size_t find_first_not_of(string_view sv, string_view set)	position of first occurrence of character not in set, or npos
find	size_t find_last(string_view sv, string_view what)	position of last occurrence of given string, or npos
	size_t find_last_of(string_view sv, string_view set)	position of last occurrence of character in set, or npos
	size_t find_last_not_of(string_view sv, string_view set)	position of last occurrence of character not in set, or npos
Modifier	char_t to_lowercase(char_t chr)	character transformed to lowercase
	char_t to_uppercase(char_t chr)	character transformed to uppercase
	string to_lowercase(string_view sv)	string transformed to lowercase
	string to_uppercase(string_view sv)	string transformed to uppercase
case	string capitalize(string_view sv)	string transformed to start with capital
substring	string substring(string_view sv, size_t pos [, size_t count])	substring starting at given position of given length, default up to end
erase	string erase(string_view sv, size_t pos [, size_t count])	string with substring at given position of given length removed, default up to end
	string erase_all(string_view sv, string_view what)	string with all occurrences of 'what' removed
	string erase_first(string_view sv, string_view what)	string with first occurrence of 'what' removed
	string erase_last(string_view sv, string_view what)	string with last occurrence of 'what' removed
insert	string insert(string_view sv, size_t pos, string_view what)	string with substring 'what' inserted at given position
replace	string replace(string_view sv, size_t pos, size_t length, string_view with)	string with substring pos to pos+length replaced with 'with'
	string replace_all(string_view sv, string_view what, string_view with)	string with all occurrences of 'what' replaced with 'with'
	string replace_first(string_view sv, string_view what, string_view with)	string with first occurrence of 'what' replaced with 'with'
	string replace_last(string_view sv, string_view what, string_view with)	string with last occurrence of 'what' replaced with 'with'
strip	string strip(string_view sv [, string_view set])	string with characters given in set stripped from left and right, default " \t\n"
	string strip_left(string_view sv [, string_view set])	string with characters given in set stripped from left, default " \t\n"
	string strip_right(string_view sv [, string_view set])	string with characters given in set stripped from right, default " \t\n"
Combining	string append(string_view head, string_view tail)	string with tail appended to head
	string join(collection<string_view> vec, string_view sep)	string with elements of collection joined with given separator string
Separating	vector<string_view> split(string_view sv, string_view set [, Nsplit])	vector of string_view with elements of string separated by characters from given set, default no limit on elements
	tuple<string_view, string_view> split_left(string_view sv, string_view set [, size_t count])	tuple with head and tail string_view on given string as split at left by characters in given set, default all in set
	tuple<string_view, string_view> split_right(string_view sv, string_view set [, size_t count])	tuple with head and tail string_view on given string as split at right by characters in given set, default all in set

Configuration

Tweak header

If the compiler supports __has_include(), string lite supports the tweak header mechanism. Provide your tweak header as nonstd/string.tweak.hpp in a folder in the include-search-path. In the tweak header, provide definitions as documented below, like #define string_CPLUSPLUS 201103L.

Provided character types

-Dstring_CONFIG_PROVIDE_XXX_T=1
Define the character type to provide the string algorithms for.

string_CONFIG_PROVIDE_XXX_T can be one or more of:

• string_CONFIG_PROVIDE_CHAR_T, default 1
• string_CONFIG_PROVIDE_WCHAR_T, default 0
• string_CONFIG_PROVIDE_CHAR8_T, default 0
• string_CONFIG_PROVIDE_CHAR16_T, default 0
• string_CONFIG_PROVIDE_CHAR32_T, default 0

Provide std::regex functions

TODO: regex function not yet available.

-Dstring_CONFIG_PROVIDE_REGEX=1
Define this to 0 if you want to compile without regular expressions. Default is 1. Note that including regular expressions incurs significant compilation overhead.

Standard selection macro

-Dstring_CPLUSPLUS=199711L
Define this macro to override the auto-detection of the supported C++ standard, if your compiler does not set the __cplusplus macro correctly.

Disable exceptions

-Dstring_CONFIG_NO_EXCEPTIONS=0
Define this to 1 if you want to compile without exceptions. If not defined, the header tries and detect if exceptions have been disabled (e.g. via -fno-exceptions). Default is undefined.

Notes and references

• n3593 - std::split(): An algorithm for splitting strings. / https://isocpp.org/files/papers/n3593.html
• Martin Broadhurst. Exploring String Splitting in C++ Programming. 2023.
• Search GitHub for C++ string algorithms.

Appendix

A.1 Compile-time information

In the test runner, the version of string-lite is available via tag [.version]. The following tags are available for information on the compiler and on the C++ standard library used: [.compiler], [.stdc++], [.stdlanguage] and [.stdlibrary].

A.2 string-lite test specification

click to expand

length: length of given string
size: length of given string
is_empty: true if string is empty
contains: true if string contains substring
contains_all_of: true if string contains all characters of set
contains_any_of: true if string contains any character of set
contains_none_of: true if string contains no character of set
starts_with: true if string starts with substring
starts_with_all_of: true if string starts with all characters of set
starts_with_any_of: true if string starts with any character of set
starts_with_none_of: true if string starts with no character of set
ends_with: true if string ends with substring
ends_with_all_of: true if string ends with all characters of set
ends_with_any_of: true if string ends with any character of set
ends_with_none_of: true if string ends with no character of set
find_first: position of first substring in string
find_last: position of last substring in string
find_first_of: position of first character in string in set
find_last_of: position of last character in string in set
find_first_not_of: position of first character in string not in set
find_last_not_of: position of last character in string not in set
capitalize: string transformed to start with capital
to_lowercase: char transformed to lowercase
to_lowercase: string transformed to lowercase
to_uppercase: char transformed to uppercase
to_uppercase: string transformed to uppercase
append: string with second string concatenated to first string
substring: substring starting at given position of given length, default up to end
erase: string with substring at given position of given length removed - default up to end
erase_all: string with all occurrences of substring removed
erase_first: string with first occurrence of substring removed
erase_last: string with last occurrence of substring removed
insert: string with substring inserted at given position
replace: string with substring given by position and length replaced
replace_all: string with all occurrences of substring replaced
replace_first: string with first occurrence of substring replaced
replace_last: string with last occurrence of substring replaced
strip_left: string with characters in set removed from left of string [" \t\n"]
strip_right: string with characters in set removed from right of string [" \t\n"]
strip: string with characters in set removed from left and right of string [" \t\n"]
join: string with strings from collection joined separated by given separator
split: split string into vector of string_view given set of delimiter characters
split_left: split string into two-element tuple given set of delimiter characters - forward
split_right: split string into two-element tuple given set of delimiter characters - reverse
compare: negative, zero or positive for lsh is less than, equal to or greater than rhs
operator==(): true if lhs string is equal to rhs string
operator!=(): true if lhs string is not equal to rhs string
operator<(): true if lhs string is less than rhs string
operator<=(): true if lhs string is less than or equal to rhs string
operator>=(): true if lhs string is greater than or equal to rhs string
operator>(): true if lhs string is greater than or equal to rhs string
tweak header: Reads tweak header if supported [tweak]