String View

A std::string_view implementation, following the same pattern as the standard with a dp::basic_string_view template and typedefs for the C++98 char types char and wchar_t. An object which contains a non-owning view of a string or contiguous character sequence. As with std::string_view, it is the programmer's responsibility to ensure that their dp::string_view does not outlive the data it is viewing.

Some liberties had to be taken on interface to preserve functionality - the standard typically processes and concatenates strings and views by converting std::string types to std::string_view types; and doing so as part of the interface for std::string. I, of course, modify the std::string types, so have to implement the elsewhere. This was achieved by adding a constructor and conversion operator for std::string types to dp::string_view, and defining the concatenation addition operators here.

Functions

begin cbegin	Returns an iterator to the beginning
end cend	Returns an iterator to the end
rbegin crbegin	Returns a reverse iterator to the beginning
rend crend	Returns a reverse iterator to the end
operator[]	Access a specified element, without bounds checking
at	Access a specified element, with bounds checking
front	Access the first character.
back	Access the last character
data	Access the viewed char array. Not guaranteed to be null-terminated
size length	Returns the number of characters in the view
max_size	Returns the maximum possible number of characters a view can track
empty	Check if the view is empty
remove_prefix	Shrinks the view by moving the front forwards
remove_suffix	Shrinks the view by moving the end backwards
swap	Swaps the contents of two views
copy	Copies characters
substr	Returns a substring
compare	Compares two views
starts_with	Checks if the string_view starts with the given prefix
ends_with	Checks if the string_view ends with the given suffix
contains	Checks if the string_view contains the given substring or character
find	Find characters in a view
rfind	Find the last occurrence of a substring
find_first_of	Find the first occurrence of characters
find_last_of	Find the last occurrence of characters
find_first_not_of	Find the first absence of characters
find_last_not_of	Find the last absence of characters
operator basic_string<CharT, Traits>	Converts a string view into its equivalent std::string type
operator== operator!= operator< operator<= operator> operator>=	Compares contents of two views according to Traits::compare()
operator<<	Performs stream output on a view
operator+ operator+=	Concatenates string_views with each other and with std::string types

Sample Code

#include <string>
#include "cpp98/string_view"

//All operations in this function have no effect on the underlying string
void ExamineString(dp::string_view str){
    if(str.size() > 10) str.remove_suffix(str.size() - 10); //Shrink view to ten characters
    
    if(str.contains("foo")) Print("This string has foo in it");
    
    for(std::size_t i = 0; i < str.size(); ++i){
        Print(i + ' '); //Print the view with a space between each character
    }
}

int main(){
    const char* literal = "Hello world";
    std::string string = "Hello world";
    char C-array[] = "Hello world";

    //No conversions or allocations take place with this call.
    ExamineString(literal);
    ExamineString(string);
    ExamineString(C-array);
}